JP6555407B2 - Non-aqueous electrolyte secondary battery and non-aqueous electrolyte - Google Patents

Description

The present invention relates to a non-aqueous electrolyte secondary battery, and more specifically, a non-aqueous electrolyte secondary battery comprising a non-aqueous electrolyte solution containing a compound having a carbon-carbon triple bond and a separator containing a specific element in a specific ratio. The present invention relates to a battery and a non-aqueous electrolyte provided in the non-aqueous electrolyte secondary battery.

Non-aqueous electrolyte secondary batteries such as lithium secondary batteries are widely used as power sources for so-called portable electronic devices such as mobile phones and notebook computers, to in-vehicle power sources for automobiles and large power sources for stationary applications. It is being put into practical use. However, with the recent high performance of electronic devices and the application to in-vehicle power supplies for driving and large power supplies for stationary applications, the demand for applied secondary batteries is increasing, and the high performance of the battery characteristics of secondary batteries is increasing. For example, it is required to achieve high levels of improvement in capacity, high temperature storage characteristics, cycle characteristics, and the like.

A non-aqueous electrolyte used for a non-aqueous electrolyte secondary battery is usually composed mainly of an electrolyte and a non-aqueous solvent. The main components of the non-aqueous solvent include cyclic carbonates such as ethylene carbonate and propylene carbonate; chain carbonates such as dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate; cyclic carboxylic acid esters such as γ-butyrolactone and γ-valerolactone. It is used.

In addition, various nonaqueous solvents, electrolytes, auxiliaries, and the like have been proposed in order to improve battery characteristics such as load characteristics, cycle characteristics, storage characteristics, and low temperature characteristics of batteries using these nonaqueous electrolyte solutions. . For example, by using vinylene carbonate and its derivatives, or vinyl ethylene carbonate derivatives, cyclic carbonates with double bonds react preferentially with the negative electrode to form a good quality film on the negative electrode surface, thereby preserving the battery. Patent Documents 1 and 2 disclose that characteristics and cycle characteristics are improved.

Further, for example, Patent Document 3 discloses that by using a specific ethylene carbonate derivative in combination with a triple bond-containing compound and / or a pentafluorophenyloxy compound, gas generation is reduced and cycle characteristics are improved. Yes.
In addition, it is known that a separator as a member constituting a non-aqueous electrolytic secondary battery is generally mixed with various metals in a polyolefin resin manufacturing process. For example, when a Ziegler-Natta catalyst is used for polymerization of polyolefin resin, Al, Mg, etc. remain.

In addition, antioxidants are introduced to prevent polyolefins from oxidizing during storage,
At the same time, it is disclosed in Patent Documents 4 to 6 that Ca and Zn are used in the metal soap introduced as a neutralizing agent for the antioxidant, and these also remain.

JP-A-8-45545 JP-A-4-87156 WO 2006-077763 WO2008-035674 WO2008-059806 WO2009-136648

As described above, the demand for higher performance of non-aqueous electrolyte secondary batteries in recent years has increased, and the characteristics of non-aqueous electrolyte secondary batteries have been improved. There is a need for improvement.
Under such a background, in the non-aqueous electrolyte secondary battery using the cyclic carbonate having a double bond as the non-aqueous electrolyte described in Patent Documents 1 and 2, the electrode surface is protected and the storage characteristics and Although battery durability such as cycle characteristics is improved, when a charged battery is left at a high temperature or a continuous charge / discharge cycle is performed, unsaturated cyclic carbonate or its derivative is oxidized and decomposed on the positive electrode to generate carbon dioxide gas. There was a problem that occurred. If carbon dioxide gas is generated in such a use environment, the battery itself may become unusable due to, for example, activation of a battery safety valve or expansion of the battery.

Moreover, in the nonaqueous electrolyte secondary battery using a triple bond-containing compound as a nonaqueous electrolyte described in Patent Document 3, a triple bond-containing compound or the like is used as a nonaqueous electrolyte.
When the electrode density is increased to increase the capacity, there is a problem that the reactivity with the electrolytic solution is large and the cycle characteristics are difficult to improve.
Moreover, in the non-aqueous electrolyte secondary battery using the separator containing elements such as Ca and Al as described in Patent Documents 4 to 6, when trying to improve the durability, these Depending on the contamination species and the contamination amount, battery performance may be greatly affected.

Therefore, the present invention provides a non-aqueous electrolyte secondary battery in which durability characteristics such as cycle are improved while solving the above-mentioned various problems that are expressed with respect to required performance in recent secondary batteries. Another object of the present invention is to provide a non-aqueous electrolyte suitable for the non-aqueous electrolyte secondary battery.

As a result of intensive studies to solve the above problems, the inventors have developed a technique for significantly improving battery durability by using a non-aqueous electrolyte containing a compound having a carbon-carbon triple bond. Further, it was found that durability is specifically improved by using the separator together with a separator containing calcium element and having a calcium element concentration of 300 ppm or less in the separator. The invention has been completed.

That is, the gist of the present invention is as follows.
Nonaqueous electrolyte solution comprising a nonaqueous electrolyte solution containing an electrolyte and a nonaqueous solvent that dissolves the electrolyte, a negative electrode capable of occluding and releasing lithium ions, a positive electrode, and a separator having a polyolefin resin as a component. An electrolyte secondary battery,
The non-aqueous electrolyte contains a compound having a carbon-carbon triple bond,
The separator contains a calcium element, and the concentration of the calcium element contained in the separator is 300 ppm or less. (Claim 1)
Another gist of the present invention resides in a non-aqueous electrolyte secondary battery characterized in that the concentration of calcium element contained in the separator according to claim 1 is 150 ppm or less. (Claim 2)
Another gist of the present invention is a non-aqueous electrolyte secondary battery characterized in that the concentration of calcium element contained in the separator according to claim 1 or 2 is 100 ppm or less. Exist. (Claim 3)
Another gist of the present invention is that the separator according to any one of claims 1 to 3 contains an aluminum element, and the concentration of the aluminum element contained in the separator is 150 ppm or less. The present invention resides in a non-aqueous electrolyte secondary battery. (
(Claim 4)
Another gist of the present invention is a non-aqueous electrolyte solution characterized in that the concentration of aluminum contained in the separator according to any one of claims 1 to 4 is 50 ppm or less. Next battery. (Claim 5)
Another gist of the present invention is that a non-aqueous electrolyte solution containing an electrolyte and a non-aqueous solvent for dissolving the electrolyte, a negative electrode capable of occluding and releasing lithium ions, a positive electrode, and a polyolefin resin A non-aqueous electrolyte secondary battery comprising a separator as a part, wherein the non-aqueous electrolyte contains a compound containing a carbon-carbon triple bond, the separator contains an aluminum element, and The concentration of aluminum contained in the separator is 15
The present invention resides in a non-aqueous electrolyte secondary battery characterized by being 0 ppm or less. (Claim 6)
Another gist of the present invention is that the compound having a carbon-carbon triple bond according to any one of claims 1 to 6 is a carbonate ester skeleton, a sulfonate ester skeleton, a sulfate ester skeleton, or a sulfite. The present invention resides in a non-aqueous electrolyte secondary battery, which is a compound having an ester skeleton. (Claim 7)
Further, another gist of the present invention is characterized in that the compound having a carbon-carbon triple bond according to any one of claims 1 to 7 is a compound having a cyclic carbonate skeleton. , Non-aqueous electrolyte secondary battery. (Claim 8)
Another gist of the present invention is that the compound having a carbon-carbon triple bond according to any one of claims 1 to 8 is represented by the following general formula (1) and / or (2): The present invention resides in a non-aqueous electrolyte secondary battery, which is a compound represented by: (Claim 9)

(In the formula _{(1) ~ (2),} R 1 ~R 9 are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, 3 to 6 carbon atoms a cycloalkyl group or having 6 to 12 carbon atoms Represents an aryl group, R
₂ and R ₃ , R ₅ and R ₆ , R ₇ and R ₈ may be bonded to each other to form a cycloalkyl group having 3 to 6 carbon atoms. x and y represent an integer of 1 or 2. Y ₁ and Y ₂ are represented by the formula (3)
It may be the same or different.

Z ₁ represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms. )
Another gist of the present invention is that the compound having the carbon-carbon triple bond according to any one of claims 1 to 8 is a compound represented by the following general formula (4). The present invention resides in a non-aqueous electrolyte secondary battery. (Claim 10)

(In the formula (4), X and Z are CR ¹ ₂ , C═O, C═N—R ¹ , C═P—R ¹ , O, S, N—
R ¹ and P—R ¹ are the same or different. Y is CR ¹ ₂ , C = O, S = O,
Represents a ^{_{S (= O) 2, P}} (= O) -R 2, P (= O) -OR 3. In the formula, R and R ¹ are hydrogen, halogen, or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and may be the same or different. R ² is a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. R ³ is Li, NR ⁴ ₄ or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. R ⁴ is a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and may be the same as or different from each other. n and m represent an integer of 0 or more. W
Is synonymous with R, and may be the same as or different from R. )
Another gist of the present invention is that the compound represented by the general formula (4) according to claim 10 is:
(5) There is a non-aqueous electrolyte secondary battery, which is a compound represented by the formula: (
(Claim 11)

(In the formula (5), Y is _{C = O, S = O,} S (= O) 2, P (= O) -R 2, P (= O) -O
R ³ is represented. )
Another gist of the present invention resides in a non-aqueous electrolyte characterized by being used for the non-aqueous electrolyte secondary battery according to any one of claims 1 to 11. (Claim 12)

The present invention provides a non-aqueous electrolyte battery and a non-aqueous electrolyte in which durability characteristics such as battery cycle are improved particularly in the design of a lithium secondary battery with high voltage and high capacity.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to these embodiments, and can be arbitrarily modified and implemented.
The non-aqueous electrolyte secondary battery of the present invention is suitable for use as, for example, an electrolyte for a lithium secondary battery among non-aqueous electrolyte batteries. The non-aqueous electrolyte secondary battery of the present invention can adopt a known structure, and typically includes a negative electrode and a positive electrode capable of occluding and releasing ions (for example, lithium ions), an aqueous electrolyte, and a separator. Is provided.

1. Non-aqueous electrolyte The non-aqueous electrolyte of the present invention relates to a non-aqueous electrolyte containing an electrolyte and a non-aqueous solvent for dissolving the electrolyte, and contains a compound having a carbon-carbon triple bond. And
1-1. Compound having carbon-carbon triple bond The non-aqueous electrolyte solution of the present invention is characterized by containing a compound having a carbon-carbon triple bond. A compound having a carbon-carbon triple bond is not particularly limited because it contributes to improving durability by suitably forming an interface protective film with an electrode. And a cyclic compound having a carbon-carbon triple bond.

Examples of the chain compound having a carbon-carbon triple bond include the following general formula (1) and / or formula (2
One or more alkyne derivatives represented by

(In the formula _{(1) ~ (2),} R 1 ~R 9 are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, 3 to 6 carbon atoms a cycloalkyl group or having 6 to 12 carbon atoms Represents an aryl group, R
₂ and R ₃ , R ₅ and R ₆ , R ₇ and R ₈ may be bonded to each other to form a cycloalkyl group having 3 to 6 carbon atoms. x and y represent an integer of 1 or 2. Y ₁ and Y ₂ are represented by the formula (3)
It may be the same or different.

Z ₁ represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms. )
Among the compounds represented by the general formula (1), 2-propynylmethyl carbonate, 1-methyl-2-propynylmethyl carbonate, 1,1-dimethyl-2-propynylmethyl carbonate, 2-propynylethyl carbonate, 1-methyl 2-propynyl ethyl carbonate, 1,1-dimethyl-2-propynyl ethyl carbonate, 2-butynyl methyl carbonate, 1-methyl-2-butynyl methyl carbonate, 1,1-dimethyl-2-
Butynylmethyl carbonate, formic acid-2-propynyl, formic acid-1-methyl-2-propynyl, formic acid-1,1-dimethyl-2-propynyl, formic acid-2-butynyl, formic acid-1-methyl-2-butynyl, formic acid -1,1-dimethyl-2-butynyl acetate, 2-propynyl acetate, 1-methyl-2-propynyl acetate, 1,1-dimethyl-2-propynyl acetate, 2-acetate
Butynyl, 1-methyl-2-butynyl acetate, 1,1-dimethyl-2-butynyl acetate,
2-propynylmethyl oxalate, 1-methyl-2-propynylmethyl oxalate,
1,1-dimethyl-2-propynylmethyl oxalate, 2-butynylmethyl oxalate, 1-methyl-2-butynylmethyl oxalate, 1,1-dimethyl-2-butynylmethyl oxalate, 2-propynyl Ethyl oxalate, 1-methyl-2-propynyl ethyl oxalate, 1,1-dimethyl-2-propynyl ethyl oxalate, 2-butynyl ethyl oxalate, 1-methyl-2-butynyl ethyl oxalate, 1, 1-dimethyl-2-butynylethyl oxalate, methanesulfonic acid-2-propynyl, methanesulfonic acid-1-methyl-2-propynyl, methanesulfonic acid-1,1-dimethyl-2-propynyl, methanesulfonic acid- 2-butynyl, methanesulfonic acid-1-methyl-2-butynyl, methanesulfonic acid-1, -Dimethyl-2-butynyl, trifluoromethanesulfonic acid-2-propynyl, trifluoromethanesulfonic acid-1-methyl-2-propynyl, trifluoromethanesulfonic acid-1,1-dimethyl-2-propynyl, trifluoromethanesulfonic acid-2 -Butynyl, trifluoromethanesulfonic acid-1-methyl-2-butynyl, trifluoromethanesulfonic acid-1,1-dimethyl-2-butynyl, trifluoroethanesulfonic acid-2-propynyl, trifluoroethanesulfonic acid-1-methyl 2-propynyl, trifluoroethanesulfonic acid-1,1-dimethyl-2-propynyl, trifluoroethanesulfonic acid-2-butynyl, trifluoroethanesulfonic acid-1-methyl-2
-Butynyl, trifluoroethanesulfonic acid-1,1-dimethyl-2-butynyl, benzenesulfonic acid-2-propynyl, benzenesulfonic acid-1-methyl-2-propynyl, benzenesulfonic acid-1,1-dimethyl-2 -Propynyl, benzenesulfonic acid-2-butynyl, benzenesulfonic acid-1-methyl-2-butynyl, benzenesulfonic acid-1,1-
Dimethyl-2-butynyl, p-toluenesulfonic acid-2-propynyl, p-toluenesulfonic acid-1-methyl-2-propynyl, p-toluenesulfonic acid-1,1-dimethyl-2
-Propynyl, p-toluenesulfonic acid-2-butynyl, p-toluenesulfonic acid-1-
Methyl-2-butynyl, p-toluenesulfonic acid-1,1-dimethyl-2-butynyl, methylsulfuric acid-2-propynyl, methylsulfuric acid-1-methyl-2-propynyl, methylsulfuric acid-1
, 1-dimethyl-2-propynyl, methyl sulfate-2-butynyl, methyl sulfate-1-methyl-2-butynyl, methyl sulfate-1,1-dimethyl-2-propynyl, ethyl sulfate-2-propynyl, ethyl sulfate- 1-methyl-2-propynyl, ethyl sulfate-1,1-dimethyl-
2-propynyl, ethyl sulfate-2-butynyl, ethyl sulfate-1-methyl-2-butynyl,
One or more selected from ethyl sulfate-1,1-dimethyl-2-butynyl is preferred,
2-propynylmethyl carbonate, 1-methyl-2-propynylmethyl carbonate, 1,1-dimethyl-2-propynylmethyl carbonate, 2-propynylethyl carbonate, 2-butynylmethyl carbonate, formic acid-2-propynyl, formic acid-1 -Methyl-
2-propynyl, formic acid-1,1-dimethyl-2-propynyl, formate-2-butynyl acetate, 2-propynyl acetate, 1-methyl-2-propynyl acetate, 1,1-dimethyl-2-acetate
Propynyl, 2-butynyl acetate, 2-propynylmethyl oxalate, 1-methyl-2
-Propynylmethyl oxalate, 1,1-dimethyl-2-propynylmethyl oxalate, 2-butynylmethyl oxalate, methanesulfonic acid-2-propynyl, methanesulfonic acid-1-methyl-2-propynyl, methanesulfonic acid -1,1-dimethyl-2-propynyl, methanesulfonic acid-2-butynyl, methanesulfonic acid-1-methyl-2-butynyl, methylsulfuric acid-2-propynyl, methylsulfuric acid-1-methyl-2-propynyl, methyl It is preferable to contain one or more selected from sulfuric acid-1,1-dimethyl-2-propynyl and methylsulfuric acid-2-butynyl.

Among the compounds represented by the general formula (2), di (2-propynyl) carbonate, di (2
-Butynyl) carbonate, di (1-methyl-2-propynyl) carbonate, di (1-
Methyl-2-butynyl) carbonate, di (1,1-dimethyl-2-propynyl) carbonate, di (1,1-dimethyl-2-butynyl) carbonate, di (2-propynyl) oxalate, di (2-butynyl) Oxalate, di (1-methyl-2-propynyl) oxalate, di (1-methyl-2-butynyl) oxalate, di (1,1-dimethyl-2-
Propynyl) oxalate, di (1,1-dimethyl-2-butynyl) oxalate, di (
2-propynyl) sulfite, di (2-butynyl) sulfite, di (1-methyl-2)
-Propynyl) sulfite, di (1-methyl-2-butynyl) sulfite, di (1,
1-dimethyl-2-propynyl) sulfite, di (1,1-dimethyl-2-butynyl)
Sulfite, di (2-propynyl) sulfuric acid, di (2-butynyl) sulfuric acid, di (1-methyl-
2-propynyl) sulfuric acid, di (1-methyl-2-butynyl) sulfuric acid, di (1,1-dimethyl-
One or more selected from 2-propynyl) sulfuric acid and di (1,1-dimethyl-2-butynyl) sulfuric acid are preferred,
Di (2-propynyl) carbonate, di (2-butynyl) carbonate, di (2-propynyl) oxalate, di (2-butynyl) oxalate, di (2-propynyl) sulfuric acid,
It is preferable to contain one or more selected from di (2-butynyl) sulfuric acid.

Among the alkyne derivatives, the most preferred compounds are 2-propynylmethyl carbonate, 2-propynylethyl carbonate, 2-butynylmethyl carbonate, and formic acid-2.
-Propynyl, 2-butynyl formate, 2-propynyl acetate, 2-butynyl acetate, 2-
Propynylmethyl oxalate, 2-butynylmethyl oxalate, methanesulfonic acid
2-propynyl, 2-butynyl methanesulfonate, 1-methyl-2 methanesulfonate
-Butynyl, methyl sulfate-2-propynyl, methyl sulfate-2-butynyl, di (2-propynyl) carbonate, di (2-butynyl) carbonate, di (2-propynyl) oxalate, di (2-butynyl) oxalate, di It is at least one compound selected from (2-propynyl) sulfuric acid and di (2-butynyl) sulfuric acid.

The compounds represented by the general formulas (1) to (2) may be used alone or in combination of two or more in any combination and ratio. Moreover, the compounding quantity of the compound represented by General formula (1)-(2) is not restrict | limited in particular, As long as the effect of this invention is not impaired remarkably, it is arbitrary.
The compounding amount of the compounds represented by the general formulas (1) to (2) is 100% by mass of the non-aqueous electrolyte solution.
Preferably, it is 0.001% by mass or more, more preferably 0.01% by mass or more, further preferably 0.1% by mass or more, and preferably 5% by mass or less, more preferably 4% by mass.
Hereinafter, it is more preferably 3% by mass or less. Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient cycle characteristics improving effect, and the high temperature storage characteristics are reduced, the amount of gas generated is increased, and the discharge capacity maintenance rate is reduced. Easy to avoid. On the other hand, if the amount is too small, the effects of the present invention may not be sufficiently exerted. If the amount is too large, the resistance may increase and the output and load characteristics may decrease.
When the compound having a carbon-carbon triple bond is a cyclic compound, the following general formula (
It is preferable that it is a compound represented by 4).

(In the formula (4), X and Z are CR ¹ ₂ , C═O, C═N—R ¹ , C = P—R ¹ , O, S, N.
-R ^1, represents a ^{P-R 1,} may be the same or different. Y is CR ¹ ₂ , C = O, S =
Represents _O, ^{S (= O) 2, P} (= O) -R 2, P (= O) -OR 3. In the formula, R and R ¹ are hydrogen, halogen, or an optionally substituted hydrocarbon group having 1 to 20 carbon atoms,
They may be the same or different. R ² may have a substituent having 1 to 2 carbon atoms
0 hydrocarbon group. R ³ is Li, NR ⁴ ₄ or 1 carbon atom which may have a substituent.
To 20 hydrocarbon groups. R ⁴ is a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and may be the same as or different from each other. n and m represent an integer of 0 or more. W has the same meaning as R, and may be the same as or different from R. )
In general formula (4), X and Z is not particularly limited as long as the scope described in the aforementioned general formula (4), _{^{preferably, CR 1 2, O, S}} , N-R 1 is more preferred. Y is also the general formula (4)
Is not particularly limited, but preferably C═O, S═O, S (═O) _2.
, P (═O) —R ² and P (═O) —OR ³ are more preferable. R and R ¹ are not particularly limited as long as they are within the range described in formula (4), but preferably have hydrogen, fluorine, a saturated aliphatic hydrocarbon group which may have a substituent, or a substituent. Examples thereof may include an unsaturated aliphatic hydrocarbon group which may be substituted, and an aromatic hydrocarbon group which may have a substituent.

R ² and R ⁴ are not particularly limited as long as they are within the range described in the general formula (4), but are preferably a saturated aliphatic hydrocarbon group that may have a substituent or a substituent. Examples thereof include unsaturated aliphatic hydrocarbons and optionally substituted aromatic hydrocarbons / aromatic heterocycles.
R ³ is not particularly limited as long as it is in the range described in the general formula (4), but preferably Li,
Examples thereof include a saturated aliphatic hydrocarbon which may have a substituent, an unsaturated aliphatic hydrocarbon which may have a substituent, and an aromatic hydrocarbon / aromatic heterocycle which may have a substituent.

Substituents of saturated aliphatic hydrocarbons which may have substituents, unsaturated aliphatic hydrocarbons which may have substituents, aromatic hydrocarbons and aromatic heterocycles which may have substituents Is not particularly limited, but preferably has a saturated aliphatic hydrocarbon group, which may have a substituent such as halogen, carboxylic acid, carbonic acid, sulfonic acid, phosphoric acid, phosphorous acid, etc. And an unsaturated aliphatic hydrocarbon group that may be substituted, an ester of an aromatic hydrocarbon group that may have a substituent, and the like, more preferably halogen, and most preferably fluorine.

Preferable saturated aliphatic hydrocarbons include, specifically, methyl group, ethyl group, fluoromethyl group, difluoromethyl group, trifluoromethyl group, 1-fluoroethyl group, 2-fluoroethyl group, 1,1-difluoroethyl. Group, 1,2-difluoroethyl group, 2,2-difluoroethyl group, 1,1,2-trifluoroethyl group, 1,2,2-trifluoroethyl group, 2,2,2-trifluoroethyl group A phenyl group, a cyclopentyl group, and a cyclohexyl group are preferred.

Specific preferred unsaturated aliphatic hydrocarbons include ethenyl, 1-fluoroethenyl, 2-fluoroethenyl, 1-methylethenyl, 2-propenyl, and 2-fluoro-2-propenyl. 3-fluoro-2-propenyl group, ethynyl group, 2-fluoroethynyl group, 2-propynyl group, and 3-fluoro-2propynyl group are preferable.
Preferred aromatic hydrocarbons include phenyl group, 2-fluorophenyl group, 3-fluorophenyl group, 2,4-difluorophenyl group, 2,6-difluorophenyl group, 3, 5
-A difluorophenyl group, 2,4,6-trifluorophenyl group is preferable.

Preferred aromatic heterocycles are 2-furanyl group, 3-furanyl group, 2-thiophenyl group, 3-thiophenyl group, 1-methyl-2-pyrrolyl group, and 1-methyl-3-pyrrolyl group.
Among these, methyl group, ethyl group, fluoromethyl group, trifluoromethyl group, 2
-Fluoroethyl group, 2,2,2-trifluoroethyl group, ethenyl group, ethynyl group, and phenyl group are preferable.

More preferably, a methyl group, an ethyl group, and an ethynyl group are preferable.
n and m are not particularly limited as long as they are in the range described in the general formula (4).
Or 1, more preferably n = m = 1 or n = 1, m = 0.
The molecular weight is preferably 50 or more. Moreover, Preferably it is 500 or less. If it is this range, it will be easy to ensure the solubility of the unsaturated cyclic carbonate with respect to a non-aqueous electrolyte solution, and the effect of this invention will fully be expressed easily.

Moreover, it is preferable that R is hydrogen, a fluorine, or an ethynyl group from both the reactivity and stability of the compound of the general formula (1). In the case of other substituents, the reactivity is lowered, and the expected properties may be lowered. Moreover, when it is halogen other than fluorine, there is a possibility that the reactivity is too high and the side reaction increases.
The number of fluorine or ethynyl groups in R is preferably within 2 in total. If the number is too large, the compatibility with the electrolytic solution may be deteriorated, and the reactivity may be too high to increase the side reaction.

Among these, n = 1 and m = 0 are preferable. When both are 0, stability deteriorates from the distortion of the ring, the reactivity becomes too high, and there is a possibility that side reactions increase. N =
Even if it is 2 or more or n = 1, if m = 1 or more, there is a possibility that the chain is more stable than the ring and the initial characteristics may not be exhibited.
Furthermore, wherein, X and Z are, ^CR _{1 2} or O are more preferred. In cases other than these, the reactivity may be too high and side reactions may increase.

The molecular weight is more preferably 100 or more, and more preferably 200 or less. If it is this range, it will be easy to ensure further the solubility of General formula (4) with respect to a non-aqueous electrolyte solution, and the effect of this invention will be fully further easily expressed.
More preferably, R is all hydrogen. In this case, the side reaction is most likely to be suppressed while maintaining the expected characteristics. When Y is C = O or S = O,
When either one of X and Z is O, Y is S (═O) ₂ , P (═O) —R ² , P (
In the case of ═O) —OR ³ , X and Z are both O or CH ₂ , or either X or Z is O
And the other is preferably CH ₂ . When Y is C═O or S═O, if both X and Z are CH ₂ , the reactivity may be too high and side reactions may increase.
Specific examples of these compounds are shown below.

Of the compounds represented by the general formula (4), the compound represented by the general formula (5) is preferable from the viewpoint of ease of industrial production.

In the above formula (5), Y represents C═O, S═O, S (═O) ₂ , P (═O) —R ² , P (═O) —.
Represents OR ³ Specific examples of these compounds having preferable conditions are shown below.

The said compound which has a carbon-carbon triple bond may be used individually by 1 type, or may have 2 or more types together by arbitrary combinations and ratios. Moreover, the compounding quantity of the compound which has a carbon-carbon triple bond is not restrict | limited especially, unless the effect of this invention is impaired remarkably. The compounding amount of the compound having a carbon-carbon triple bond is preferably 0.00% in 100% by mass of the non-aqueous electrolyte solution.
1% by mass or more, more preferably 0.01% by mass or more, further preferably 0.1% by mass or more, preferably 5% by mass or less, more preferably 4% by mass or less, and further preferably 3% by mass. It is as follows. Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient cycle characteristics improving effect, and the high temperature storage characteristics are reduced, the amount of gas generated is increased, and the discharge capacity maintenance rate is reduced. Easy to avoid. On the other hand, if the amount is too small, the effects of the present invention may not be sufficiently exerted. If the amount is too large, the resistance may increase and the output and load characteristics may decrease.

1-2. Electrolyte <Lithium salt>
As the electrolyte, a lithium salt is usually used. The lithium salt is not particularly limited as long as it is known to be used in this application, and any lithium salt can be used.
Specific examples include the following.

For _{example, LiPF 6, LiBF 4, LiClO} 4, LiAlF 4, LiSbF 6, Li
Inorganic lithium salts such as NbF ₆ , LiTaF ₆ and LiWF ₇ ;
Lithium fluorophosphates such as LiPO ₃ F and LiPO ₂ F ₂ ;
Lithium tungstates such as LiWOF ₅ ;
HCO ₂ Li, CH ₃ CO ₂ Li, CH ₂ FCO ₂ Li, CHF ₂ CO ₂ Li, CF ₃
CO ₂ Li, CF ₃ CH ₂ CO ₂ Li, CF ₃ CF ₂ CO ₂ Li, CF ₃ CF ₂ CF ₂ C
Carboxylic acid lithium salts such as O ₂ Li, CF ₃ CF ₂ CF ₂ CF ₂ CO ₂ Li;
FSO ₃ Li, CH ₃ SO ₃ Li, CH ₂ FSO ₃ Li, CHF ₂ SO ₃ Li, CF ₃
SO ₃ Li, CF ₃ CF ₂ SO ₃ Li, CF ₃ CF ₂ CF ₂ SO ₃ Li, CF ₃ CF ₂ C
Sulfonic acid lithium salts such as F ₂ CF ₂ SO ₃ Li;
LiN (FCO) ₂ , LiN (FCO) (FSO ₂ ), LiN (FSO ₂ ) ₂ , LiN
(FSO ₂ ) (CF ₃ SO ₂ ), LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ )
₂ , lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3
- perfluoropropane _{disulfonylimide, LiN (CF 3 SO 2)} (C 4 F 9 SO 2
) Lithium imide salts;
Lithium metide salts such as LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ ;
Lithium oxalatoborate salts such as lithium difluorooxalatoborate and lithium bis (oxalato) borate;
Lithium oxalate phosphate salts such as lithium tetrafluorooxalatophosphate, lithium difluorobis (oxalato) phosphate, lithium tris (oxalato) phosphate;
In addition, LiPF ₄ (CF ₃ ) ₂ , LiPF ₄ (C ₂ F ₅ ) ₂ , LiPF ₄ (CF ₃ S
O ₂ ) ₂ , LiPF ₄ (C ₂ F ₅ SO ₂ ) ₂ , LiBF ₃ CF ₃ , LiBF ₃ C ₂ F ₅ ,
LiBF ₃ C ₃ F ₇ , LiBF ₂ (CF ₃ ) ₂ , LiBF ₂ (C ₂ F ₅ ) ₂ , LiBF ₂
Fluorine-containing organic lithium salts such as (CF ₃ SO ₂ ) ₂ and LiBF ₂ (C ₂ F ₅ SO ₂ ) ₂ ;
Etc.

Among them, LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiTaF ₆ , LiPO ₂ F ₂ , F
SO ₃ Li, CF ₃ SO ₃ Li, LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ S
O ₂ ), LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2
-Perfluoroethane disulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂
F ₅ SO ₂ ) ₃ , lithium bisoxalatoborate, lithium difluorooxalatoborate, lithium tetrafluorooxalatophosphate, lithium difluorobisoxalatophosphate, lithium tris (oxalato) phosphate, LiBF ₃ CF ₃
, LiBF ₃ C ₂ F ₅ , LiPF ₃ (CF ₃ ) ₃ , LiPF ₃ (C ₂ F ₅ ) _{3 and the} like are effective in improving output characteristics, high-rate charge / discharge characteristics, high-temperature storage characteristics, cycle characteristics, and the like. Particularly preferred.

These lithium salts may be used alone or in combination of two or more. A preferable example in the case of using 2 or more types together is LiPF ₆ and LiBF ₄ , LiPF ₆ and FSO ₃ Li, Li
The combination of PF ₆ and LiPO ₂ F ₂ has the effect of improving load characteristics and cycle characteristics. Among these, the combined use of LiPF ₆ and FSO ₃ Li, or LiPF ₆ and LiPO ₂ F ₂ is preferable because the effect is remarkable.

When LiPF ₆ and LiBF ₄ , LiPF ₆ and FSO ₃ Li are used in combination, the concentration of LiBF ₄ or FSO ₃ Li with respect to 100% by mass of the total amount of the non-aqueous electrolyte is not limited, and the effect of the present invention is not significantly impaired. As long as it is optional, it is usually 0.01% by mass or more, preferably 0.1% by mass or more, and the upper limit is usually 30% by mass or less, preferably 20% with respect to the non-aqueous electrolyte solution of the present invention. It is below mass%. On the other hand, even when LiPF ₆ and LiPO ₂ F ₂ are used in combination, the concentration of LiPO ₂ F ₂ with respect to 100% by mass of the entire non-aqueous electrolyte is not limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. However, with respect to the non-aqueous electrolyte solution of the present invention, it is usually 0.001% by mass or more, preferably 0.01% by mass or more, while its upper limit is usually 10% by mass or less, preferably 5% by mass or less. is there. Within this range, effects such as output characteristics, load characteristics, low temperature characteristics, cycle characteristics, and high temperature characteristics are improved. On the other hand, if it is too much, it may be deposited at low temperature to deteriorate the battery characteristics, and if it is too little, the effect of improving the low temperature characteristics, cycle characteristics, high temperature storage characteristics, etc. may be reduced.

Here, the preparation of the electrolyte solution in the case of incorporating the LiPO ₂ F ₂ in the electrolyte solution, Ya separately active material method and later be added to the electrolytic solution containing LiPF ₆ and LiPO ₂ F ₂ synthesized by a known method A method of generating LiPO ₂ F ₂ in the system when water is allowed to coexist in a battery component such as an electrode plate and assembling a battery using an electrolyte containing LiPF ₆ is used. You may use the method of.

The method for measuring the content of LiPO ₂ F ₂ in the non-aqueous electrolyte and the non-aqueous electrolyte battery is not particularly limited, and any known method can be used. Examples include ion chromatography and F nuclear magnetic resonance spectroscopy (hereinafter sometimes abbreviated as NMR).
Another example is the combined use of an inorganic lithium salt and an organic lithium salt, and the combined use of both has the effect of suppressing deterioration due to high-temperature storage. As an organic lithium salt, CF ₃ SO ₃
Li, LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ SO ₂ ), LiN (CF ₃ S
O ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, Li
C (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ , lithium bisoxalatoborate, lithium difluorooxalatoborate, lithium tetrafluorooxalatophosphate, lithium difluorobisoxa Latophosphate, Li
BF ₃ CF ₃ , LiBF ₃ C ₂ F ₅ , LiPF ₃ (CF ₃ ) ₃ , LiPF ₃ (C ₂ F ₅ )
_It is preferably ₃ etc. In this case, the ratio of the organic lithium salt to 100% by mass of the whole non-aqueous electrolyte is preferably 0.1% by mass or more, particularly preferably 0.5% by mass or more, preferably 30% by mass or less, particularly preferably. It is 20 mass% or less.

The concentration of these lithium salts in the non-aqueous electrolyte solution is not particularly limited as long as the effects of the present invention are not impaired, but the electric conductivity of the electrolyte solution is in a good range, and good battery performance is ensured. Therefore, the total molar concentration of lithium in the non-aqueous electrolyte is preferably 0.3 mol /
L or more, more preferably 0.4 mol / L or more, still more preferably 0.5 mol / L or more, preferably 3 mol / L or less, more preferably 2.5 mol / L or less, still more preferably 2.0 mol. / L or less. If it is this range, effects, such as a low temperature characteristic, cycling characteristics, and a high temperature characteristic, will improve. On the other hand, if the total molar concentration of lithium is too low, the electrical conductivity of the electrolyte may be insufficient. On the other hand, if the concentration is too high, the electrical conductivity may decrease due to an increase in viscosity. May decrease.

The lithium salt is not particularly limited, and can be used even if it is synthesized using any method or obtained. For example, the synthesis method of FSO ₃ Li is not particularly limited, but a method of obtaining lithium fluorosulfonate by reacting lithium fluoride or a lithium silicon fluoride compound with sulfur trioxide, or reacting fluorosulfonic acid with lithium. A method of obtaining lithium fluorosulfonate, a method of obtaining lithium fluorosulfonate by reacting ammonium fluorosulfonate with lithium, a reaction of lithium fluorocarboxylate with lithium fluorosulfonate by ion exchange method And a method of obtaining a metal salt of fluorosulfonic acid by reacting fluorosulfonic acid and lithium halide. Examples of the method for obtaining lithium fluorosulfonate by ion exchange include a copolymer of styrene and divinylbenzene, a copolymer of methacrylic acid and divinylbenzene, and a copolymer of acrylic acid and divinylbenzene. Inorganic, such as lithium hydroxide, using a known styrene resin having a three-dimensional network structure, methacrylic acid resin or acrylic acid resin, preferably using an ion exchange resin in which a cation exchange group such as carboxylic acid is introduced A method in which a lithium alkoxide such as an aqueous lithium salt solution or lithium methoxide is allowed to act on the resin to carry a lithium cation and then fluorosulfonic acid is allowed to act on the resin to obtain lithium fluorosulfonate is suitably used. The

1-3. Solvent As the non-aqueous solvent, a saturated cyclic carbonate, a cyclic carbonate having a fluorine atom, a chain carbonate, a cyclic and chain carboxylic acid ester, an ether compound, a sulfone compound, and the like can be used.
<Saturated cyclic carbonate>
Examples of the saturated cyclic carbonate include those having an alkylene group having 2 to 4 carbon atoms.

Specifically, as the saturated cyclic carbonate having 2 to 4 carbon atoms, ethylene carbonate,
Examples include propylene carbonate and butylene carbonate. Among these, ethylene carbonate and propylene carbonate are particularly preferable from the viewpoint of improving battery characteristics resulting from an improvement in the degree of lithium ion dissociation.
A saturated cyclic carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios.

The blending amount of the saturated cyclic carbonate is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The lower limit of the blending amount when one kind is used alone is 5% in 100% by volume of the non-aqueous solvent. Volume% or more, more preferably 10 volume% or more. By setting this range, the decrease in electrical conductivity resulting from the decrease in the dielectric constant of the non-aqueous electrolyte is avoided, and the large current discharge characteristics, negative electrode stability, and cycle characteristics of the non-aqueous electrolyte secondary battery are good. It becomes easy to be in a range. Moreover, an upper limit is 95 volume% or less, More preferably, it is 90 volume% or less, More preferably, it is 85 volume% or less. By setting it as this range, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, a decrease in ionic conductivity is suppressed, and as a result, the load characteristics of the non-aqueous electrolyte secondary battery are easily set in a favorable range.

Moreover, one of the preferable combinations when using 2 or more types of saturated cyclic carbonates by arbitrary combinations is a combination to ethylene carbonate and propylene carbonate. In this case, the volume ratio of ethylene carbonate to propylene carbonate is 99: 1 to 40:
60 is preferable, and 95: 5 to 50:50 is particularly preferable. Furthermore, the amount of propylene carbonate in the entire non-aqueous solvent is 0.1% by volume or more, preferably 1% by volume or more, more preferably 2% by volume or more, and the upper limit is usually 20% by volume or less, preferably 8% by volume. %Less than,
More preferably, it is 5 volume% or less. When propylene carbonate is contained in this range,
This is preferable because the low temperature characteristics are further excellent while maintaining the combination characteristics of ethylene carbonate and dialkyl carbonates.

<Cyclic carbonate having a fluorine atom>
The cyclic carbonate having a fluorine atom (hereinafter sometimes abbreviated as “fluorinated cyclic carbonate”) is not particularly limited as long as it is a cyclic carbonate having a fluorine atom.
Examples of the fluorinated cyclic carbonate include derivatives of cyclic carbonates having an alkylene group having 2 to 6 carbon atoms, such as ethylene carbonate derivatives. Examples of the ethylene carbonate derivative include fluorinated products of ethylene carbonate or ethylene carbonate substituted with an alkyl group (for example, an alkyl group having 1 to 4 carbon atoms), and particularly those having 1 to 8 fluorine atoms. Is preferred.

Specifically, monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, 4-fluoro-4-methylethylene carbonate, 4,5-difluoro-4-methylethylene carbonate, 4- Fluoro-
5-methylethylene carbonate, 4,4-difluoro-5-methylethylene carbonate, 4- (fluoromethyl) -ethylene carbonate, 4- (difluoromethyl) -ethylene carbonate, 4- (trifluoromethyl) -ethylene carbonate, 4 -(Fluoromethyl) -4-fluoroethylene carbonate, 4- (fluoromethyl) -5-fluoroethylene carbonate, 4-fluoro-4,5-dimethylethylene carbonate, 4,
5-difluoro-4,5-dimethylethylene carbonate, 4,4-difluoro-5,5
-Dimethyl ethylene carbonate etc. are mentioned.

Among them, at least one selected from the group consisting of monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, and 4,5-difluoro-4,5-dimethylethylene carbonate has high ionic conductivity. It is more preferable in terms of imparting properties and suitably forming an interface protective film.
A fluorinated cyclic carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios. The blending amount of the fluorinated cyclic carbonate is not particularly limited,
It is optional as long as the effects of the present invention are not significantly impaired, but in 100% by volume of the non-aqueous solvent, preferably 0.01% by volume or more, more preferably 0.1% by volume or more, and further preferably 0.2% by volume or more. Moreover, it is preferably 95% by volume or less, more preferably 90% by volume or less. Within this range, the non-aqueous electrolyte secondary battery tends to exhibit a sufficient cycle characteristic improvement effect, and avoids a decrease in discharge capacity maintenance rate due to a decrease in high-temperature storage characteristics or an increase in the amount of gas generated. Cheap.

In addition, the cyclic carbonate which has a fluorine atom expresses an effective function not only as a solvent but also as an auxiliary agent described in the following 1-3. There is no clear boundary in the blending amount when used as a cyclic carbonate solvent / auxiliary having a fluorine atom, and the blending amount described in the previous paragraph can be followed as it is.

<Chain carbonate>
As a chain carbonate, a C3-C7 thing is preferable.
Specifically, as the chain carbonate having 3 to 7 carbon atoms, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-
Propyl isopropyl carbonate, ethyl methyl carbonate, methyl-n-propyl carbonate, n-butyl methyl carbonate, isobutyl methyl carbonate, t-butyl methyl carbonate, ethyl-n-propyl carbonate, n-butyl ethyl carbonate, isobutyl ethyl carbonate, t- Examples include butyl ethyl carbonate.

Among them, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethyl methyl carbonate, and methyl n-propyl carbonate are preferable, and dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate are particularly preferable. is there.
Also, chain carbonates having fluorine atoms (hereinafter referred to as “fluorinated chain carbonate”)
Can also be used preferably. The number of fluorine atoms contained in the fluorinated chain carbonate is not particularly limited as long as it is 1 or more, but is usually 6 or less, preferably 4 or less. When the fluorinated chain carbonate has a plurality of fluorine atoms, they may be bonded to the same carbon or may be bonded to different carbons. Examples of the fluorinated chain carbonate include a fluorinated dimethyl carbonate derivative, a fluorinated ethyl methyl carbonate derivative, and a fluorinated diethyl carbonate derivative.

Fluorinated dimethyl carbonate derivatives include fluoromethyl methyl carbonate,
Difluoromethyl methyl carbonate, trifluoromethyl methyl carbonate, bis (
Fluoromethyl) carbonate, bis (difluoro) methyl carbonate, bis (trifluoromethyl) carbonate and the like.
Fluorinated ethyl methyl carbonate derivatives include 2-fluoroethyl methyl carbonate, ethyl fluoromethyl carbonate, 2,2-difluoroethyl methyl carbonate, 2-fluoroethyl fluoromethyl carbonate, ethyl difluoromethyl carbonate, 2,2,2-trimethyl Examples include fluoroethyl methyl carbonate, 2,2-difluoroethyl fluoromethyl carbonate, 2-fluoroethyl difluoromethyl carbonate, and ethyl trifluoromethyl carbonate.

Fluorinated diethyl carbonate derivatives include ethyl- (2-fluoroethyl) carbonate, ethyl- (2,2-difluoroethyl) carbonate, bis (2-fluoroethyl) carbonate, ethyl- (2,2,2-trifluoro). Ethyl) carbonate, 2,
2-difluoroethyl-2′-fluoroethyl carbonate, bis (2,2-difluoroethyl) carbonate, 2,2,2-trifluoroethyl-2′-fluoroethyl carbonate, 2,2,2-trifluoroethyl- 2 ', 2'-difluoroethyl carbonate, bis (2,2,2-trifluoroethyl) carbonate, etc. are mentioned.

A chain carbonate may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
The amount of the chain carbonate is preferably 5% by volume or more, more preferably 10% by volume or more, and further preferably 15% by volume or more in 100% by volume of the non-aqueous solvent. By setting the lower limit in this way, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, the decrease in ionic conductivity is suppressed, and the large current discharge characteristics of the non-aqueous electrolyte secondary battery are easily set to a favorable range. Become. The chain carbonate is 90% by volume or less, more preferably 8% in 100% by volume of the non-aqueous solvent.
It is preferably 5% by volume or less. By setting the upper limit in this way, it is easy to avoid a decrease in electrical conductivity due to a decrease in the dielectric constant of the non-aqueous electrolyte and to make the large current discharge characteristics of the non-aqueous electrolyte secondary battery in a favorable range. .

The battery performance can be remarkably improved by combining ethylene carbonate at a specific blending amount with respect to the specific chain carbonate.
For example, when dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate is selected as the specific chain carbonate, the blending amount of ethylene carbonate is 10 volume% or more and 80 volume% or less, dimethyl carbonate, ethyl methyl carbonate, or diethyl It is preferable that the blending amount of carbonate is 20% by volume or more and 90% by volume or less. By selecting such a blending amount, the low-temperature deposition temperature of the electrolyte is lowered, the viscosity of the nonaqueous electrolytic solution is also lowered to improve the ionic conductivity, and a high output can be obtained even at a low temperature.

It is also preferable to use two or more types of specific chain carbonates in combination. When dimethyl carbonate and ethyl methyl carbonate are used in combination with a specific chain carbonate, the blending amount of ethylene carbonate is 10% by volume or more and 60% by volume or less, and the blending amount of dimethyl carbonate is 10% by volume or more and 70% by volume or less. The amount of ethyl methyl carbonate is 10% by volume
As mentioned above, what is 80 volume% or less is especially preferable. When a specific chain carbonate is used in combination with dimethyl carbonate and diethyl carbonate, the blending amount of ethylene carbonate is 10% by volume or more and 60% by volume or less, and the blending amount of dimethyl carbonate is 10% by volume or more and 70% by volume. Hereinafter, the blending amount of diethyl carbonate is 10% by volume or more and 70% by volume.
The following are particularly preferred. Further, when ethyl methyl carbonate and diethyl carbonate are used in combination with a specific chain carbonate, the blending amount of ethylene carbonate is 1
0 volume% or more, 60 volume% or less, the amount of ethyl methyl carbonate is 10 volume% or more,
Particularly preferred is 80% by volume or less and a blending amount of diethyl carbonate of 10% by volume or more and 70% by volume or less.

<Cyclic carboxylic acid ester>
Examples of the cyclic carboxylic acid ester include those having 3 to 12 total carbon atoms in the structural formula.
Specifically, gamma butyrolactone, gamma valerolactone, gamma caprolactone,
Epsilon caprolactone and the like. Among these, gamma butyrolactone is particularly preferable from the viewpoint of improving battery characteristics resulting from an improvement in the degree of lithium ion dissociation.

The amount of the cyclic carboxylic acid ester is usually 5% by volume or more, more preferably 10% by volume or more, in 100% by volume of the non-aqueous solvent. By setting the lower limit in this manner, the electrical conductivity of the non-aqueous electrolyte solution is improved, and the large current discharge characteristics of the non-aqueous electrolyte secondary battery are easily improved. The amount of the cyclic carboxylic acid ester is preferably 50% by volume or less,
More preferably, it is 40 volume% or less. By setting the upper limit in this way, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, a decrease in electrical conductivity is avoided, an increase in negative electrode resistance is suppressed, and a large current discharge of the non-aqueous electrolyte secondary battery is performed. It becomes easy to make a characteristic into a favorable range.

<Chain carboxylic acid ester>
Examples of the chain carboxylic acid ester include those having 3 to 7 carbon atoms in the structural formula.
Specifically, methyl acetate, ethyl acetate, acetic acid-n-propyl, isopropyl acetate, acetic acid-n-butyl, isobutyl acetate, acetic acid-t-butyl, methyl propionate, ethyl propionate, propionate-n-propyl, Isopropyl propionate, propionate-n-
Examples include butyl, isobutyl propionate, t-butyl propionate, methyl butyrate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, methyl isobutyrate, ethyl isobutyrate, n-propyl isobutyrate, and isopropyl isobutyrate. .

Among them, methyl acetate, ethyl acetate, acetate-n-propyl acetate-n-butyl acetate, methyl propionate, ethyl propionate, propionate-n-propyl, isopropyl propionate, methyl butyrate, ethyl butyrate, etc. It is preferable from the viewpoint of improvement of ionic conductivity.
The amount of the chain carboxylic acid ester is usually 100% by volume in the non-aqueous solvent, preferably 10%.
Volume% or more, more preferably 15 volume% or more. By setting the lower limit in this way,
The electric conductivity of the non-aqueous electrolyte solution is improved, and the large current discharge characteristics of the non-aqueous electrolyte secondary battery are easily improved. Moreover, the compounding quantity of chain | strand-shaped carboxylic acid ester is 60 volume% or less preferably in 100 volume% of nonaqueous solvents, More preferably, it is 50 volume% or less. By setting the upper limit in this manner, an increase in negative electrode resistance is suppressed, and the large current discharge characteristics and cycle characteristics of the non-aqueous electrolyte secondary battery are easily set in a favorable range.

<Ether compound>
As the ether compound, a part of hydrogen atoms may be substituted with fluorine atoms having 3 to 3 carbon atoms.
10 chain ethers and C3-C6 cyclic ethers are preferred.
Examples of the chain ether having 3 to 10 carbon atoms include diethyl ether, di (2-fluoroethyl) ether, di (2,2-difluoroethyl) ether, di (2,2,2-trifluoroethyl) ether, ethyl (2-fluoroethyl) ether, ethyl (2,2,2-trifluoroethyl) ether, ethyl (1,1,2,2-tetrafluoroethyl) ether, (2-fluoroethyl) (2,2,2 -Trifluoroethyl) ether, (2-fluoroethyl) (1,1,2,2-tetrafluoroethyl) ether, (2,2,2-trifluoroethyl) (1,1,2,2-tetrafluoro) Ethyl) ether, ethyl-n-propyl ether, ethyl (3-fluoro-n-propyl) ether, ethyl (3,3,3-
Trifluoro-n-propyl) ether, ethyl (2,2,3,3-tetrafluoro-n
-Propyl) ether, ethyl (2,2,3,3,3-pentafluoro-n-propyl)
Ether, 2-fluoroethyl-n-propyl ether, (2-fluoroethyl) (3-
Fluoro-n-propyl) ether, (2-fluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (2-fluoroethyl) (2,2,3,3-tetrafluoro-n- Propyl) ether, (2-fluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, 2,2,2-trifluoroethyl-n-propyl ether, (2,2, 2-trifluoroethyl) (3-fluoro-n-propyl) ether,
(2,2,2-trifluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (2,2,2-trifluoroethyl) (2,2,3,3-tetrafluoro- n-propyl) ether, (2,2,2-trifluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, 1,1,2,2-tetrafluoroethyl-n -Propyl ether, (1,1,2,2-tetrafluoroethyl) (3-fluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl) (3,3,3-trifluoro -N-propyl) ether, (1,1,2,2-tetrafluoroethyl) (2,2,3,
3-tetrafluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di-n-propylether , (N-propyl) (3-fluoro-n-propyl) ether, (n-propyl) (3,3,3-trifluoro-n-propyl) ether, (n-propyl) (2,2
, 3,3-tetrafluoro-n-propyl) ether, (n-propyl) (2,2,3,
3,3-pentafluoro-n-propyl) ether, di (3-fluoro-n-propyl)
Ether, (3-fluoro-n-propyl) (3,3,3-trifluoro-n-propyl) ether, (3-fluoro-n-propyl) (2,2,3,3-tetrafluoro-n-
Propyl) ether, (3-fluoro-n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (3,3,3-trifluoro-n-propyl) ether, (3,3,3-trifluoro-n-propyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (3,3,3-trifluoro-n-propyl) (2,2 , 3
, 3,3-pentafluoro-n-propyl) ether, di (2,2,3,3-tetrafluoro-n-propyl) ether, (2,2,3,3-tetrafluoro-n-propyl) (
2,2,3,3,3-pentafluoro-n-propyl) ether, di (2,2,3,3)
3-pentafluoro-n-propyl) ether, di-n-butyl ether, dimethoxymethane, methoxyethoxymethane, methoxy (2-fluoroethoxy) methane, methoxy (
2,2,2-trifluoroethoxy) methanemethoxy (1,1,2,2-tetrafluoroethoxy) methane, diethoxymethane, ethoxy (2-fluoroethoxy) methane, ethoxy (2,2,2-trifluoro) Ethoxy) methane, ethoxy (1,1,2,2-tetrafluoroethoxy) methane, di (2-fluoroethoxy) methane, (2-fluoroethoxy) (2,2,2-trifluoroethoxy) methane, (2 -Fluoroethoxy) (1,1
, 2,2-tetrafluoroethoxy) methanedi (2,2,2-trifluoroethoxy) methane, (2,2,2-trifluoroethoxy) (1,1,2,2-tetrafluoroethoxy) methane, di (1,1,2,2-tetrafluoroethoxy) methane, dimethoxyethane, methoxyethoxyethane, methoxy (2-fluoroethoxy) ethane, methoxy (2,
2,2-trifluoroethoxy) ethane, methoxy (1,1,2,2-tetrafluoroethoxy) ethane, diethoxyethane, ethoxy (2-fluoroethoxy) ethane, ethoxy (2,2,2-trifluoroethoxy) ) Ethane, ethoxy (1,1,2,2-tetrafluoroethoxy) ethane, di (2-fluoroethoxy) ethane, (2-fluoroethoxy) (2,2,2-trifluoroethoxy) ethane, (2- Fluoroethoxy) (1,1,
2,2-tetrafluoroethoxy) ethane, di (2,2,2-trifluoroethoxy) ethane, (2,2,2-trifluoroethoxy) (1,1,2,2-tetrafluoroethoxy) ethane, Examples include di (1,1,2,2-tetrafluoroethoxy) ethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether.

Examples of the cyclic ether having 3 to 6 carbon atoms include tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxane, 2-methyl-1,3-dioxane, 4-methyl-1,3-dioxane, 1 , 4-dioxane and the like, and fluorinated compounds thereof.
Among them, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether have high solvating ability to lithium ions and improve ion dissociation. Of these, dimethoxymethane, diethoxymethane, and ethoxymethoxymethane are preferable because they have low viscosity and give high ionic conductivity.

The compounding amount of the ether compound is usually in 100% by volume of the non-aqueous solvent, preferably 5% by volume or more, more preferably 10% by volume or more, further preferably 15% by volume or more, and preferably 70% by volume or less. More preferably, it is 60 volume% or less, More preferably, it is 50 volume% or less. If it is this range, it is easy to ensure the improvement effect of the lithium ion dissociation degree of chain ether, and the improvement of the ionic conductivity derived from a viscosity fall. It is easy to avoid a situation where the capacity is reduced due to co-insertion.

<Sulfone compound>
As the sulfone compound, a cyclic sulfone having 3 to 6 carbon atoms and a chain sulfone having 2 to 6 carbon atoms are preferable. The number of sulfonyl groups in one molecule is preferably 1 or 2.
Examples of the cyclic sulfone include trimethylene sulfones, tetramethylene sulfones, and hexamethylene sulfones that are monosulfone compounds; trimethylene disulfones, tetramethylene disulfones, and hexamethylene disulfones that are disulfone compounds. Among these, from the viewpoint of dielectric constant and viscosity, tetramethylene sulfones, tetramethylene disulfones, hexamethylene sulfones, and hexamethylene disulfones are more preferable, and tetramethylene sulfones (sulfolanes) are particularly preferable.

The sulfolane is preferably sulfolane and / or a sulfolane derivative (hereinafter sometimes abbreviated as “sulfolane” including sulfolane). As the sulfolane derivative, one in which one or more hydrogen atoms bonded to the carbon atom constituting the sulfolane ring are substituted with a fluorine atom or an alkyl group is preferable. Among them, 2-methylsulfolane, 3-methylsulfolane, 2-fluorosulfolane, 3-fluorosulfolane, 2,2-difluorosulfolane, 2,3-difluorosulfolane, 2,4-difluorosulfolane, 2,5-difluorosulfolane, 3,4-difluorosulfolane, 2-fluoro-3-methylsulfolane, 2
-Fluoro-2-methylsulfolane, 3-fluoro-3-methylsulfolane, 3-fluoro-2-methylsulfolane, 4-fluoro-3-methylsulfolane, 4-fluoro-2-
Methyl sulfolane, 5-fluoro-3-methyl sulfolane, 5-fluoro-2-methyl sulfolane, 2-fluoromethyl sulfolane, 3-fluoromethyl sulfolane, 2-difluoromethyl sulfolane, 3-difluoromethyl sulfolane, 2-trifluoromethyl Sulfolane, 3-trifluoromethylsulfolane, 2-fluoro-3- (trifluoromethyl) sulfolane, 3-fluoro-3- (trifluoromethyl) sulfolane, 4-fluoro-
3- (Trifluoromethyl) sulfolane, 5-fluoro-3- (trifluoromethyl) sulfolane and the like are preferable because of high ionic conductivity and high input / output.

As the chain sulfone, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, n-propyl ethyl sulfone, di-n-propyl sulfone, isopropyl methyl sulfone, isopropyl ethyl sulfone, diisopropyl sulfone, n- Butyl methyl sulfone, n-butyl ethyl sulfone, t-butyl methyl sulfone, t-butyl ethyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone, monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, Trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl trif Oromethylsulfone, perfluoroethylmethylsulfone, ethyltrifluoroethylsulfone, ethylpentafluoroethylsulfone, di (trifluoroethyl) sulfone, perfluorodiethylsulfone, fluoromethyl-n-propylsulfone, difluoromethyl-n-propylsulfone , Trifluoromethyl-n-
Propylsulfone, fluoromethylisopropylsulfone, difluoromethylisopropylsulfone, trifluoromethylisopropylsulfone, trifluoroethyl-n-propylsulfone, trifluoroethylisopropylsulfone, pentafluoroethyl-n-
Propyl sulfone, pentafluoroethyl isopropyl sulfone, trifluoroethyl
Examples thereof include n-butyl sulfone, trifluoroethyl-t-butyl sulfone, pentafluoroethyl-n-butyl sulfone, pentafluoroethyl-t-butyl sulfone.

Among them, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, isopropyl methyl sulfone, n-butyl methyl sulfone, t-butyl methyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone , Monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl trifluoromethyl sulfone, ethyl trifluoroethyl sulfone, ethyl pentafluoro Ethyl sulfone, trifluoromethyl-n-propyl sulfone, trifluoromethyl isopropyl sulfone, tri Ruoroechiru -n- butyl sulfone, trifluoroethyl -t- butyl sulfone, trifluoromethyl -n- butyl sulfone, trifluoromethyl -t- butyl sulfone is preferred because a higher high output ionic conductivity.

The compounding amount of the sulfone compound is usually 0.3% by volume or more, more preferably 0.5% by volume or more, and further preferably 1% by volume or more in 100% by volume of the nonaqueous solvent. Is 40% by volume or less, more preferably 35% by volume or less, and still more preferably 30% by volume or less. Within this range, durability improvement effects such as cycle characteristics and storage characteristics can be easily obtained, and the viscosity of the non-aqueous electrolyte can be set to an appropriate range to avoid a decrease in electrical conductivity. When charging / discharging an aqueous electrolyte secondary battery at a high current density, it is easy to avoid a situation in which the charge / discharge capacity retention rate decreases.

1-4. Auxiliary agent In the non-aqueous electrolyte battery of the present invention, an auxiliary agent may be appropriately used according to the purpose in addition to the compound having a carbon-carbon triple bond. Examples of the auxiliary agent include a cyclic carbonate having an unsaturated bond shown below, an unsaturated cyclic carbonate having a fluorine atom, an overcharge inhibitor, and other auxiliary agents.

<Cyclic carbonate having an unsaturated bond>
In the non-aqueous electrolyte of the present invention, in order to form a film on the negative electrode surface of the non-aqueous electrolyte battery and achieve a long battery life, in addition to the compound having a carbon-carbon triple bond, a carbon-carbon triple bond is used. A cyclic carbonate having an unsaturated bond excluding a compound having a bond (hereinafter sometimes abbreviated as “unsaturated cyclic carbonate”) can be used.

The unsaturated cyclic carbonate is not particularly limited as long as it is a cyclic carbonate having a carbon-carbon double bond, and any unsaturated carbonate can be used. The cyclic carbonate having an aromatic ring is also included in the unsaturated cyclic carbonate.
Examples of the unsaturated cyclic carbonate include vinylene carbonates, ethylene carbonates substituted with a substituent having an aromatic ring or a carbon-carbon double bond, phenyl carbonates,
Examples thereof include vinyl carbonates, allyl carbonates, catechol carbonates and the like.

As vinylene carbonates, vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, phenyl vinylene carbonate, 4,5-
Examples thereof include diphenyl vinylene carbonate, vinyl vinylene carbonate, 4,5-vinyl vinylene carbonate, allyl vinylene carbonate, 4,5-diallyl vinylene carbonate.

Specific examples of ethylene carbonates substituted with an aromatic ring or a substituent having a carbon-carbon double bond include vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate, 4-methyl-5-vinyl ethylene carbonate, 4- Allyl-5-vinylethylene carbonate, phenylethylene carbonate, 4,5-diphenylethylene carbonate,
4-phenyl-5-vinylethylene carbonate, 4-allyl-5-phenylethylene carbonate, allylethylene carbonate, 4,5-diallylethylene carbonate, 4
-Methyl-5-allylethylene carbonate and the like.

Among them, particularly preferable unsaturated cyclic carbonates for use in combination with a compound having a carbon-carbon triple bond include vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, vinyl vinylene carbonate, and 4,5-vinyl vinylene carbonate. , Allyl vinylene carbonate, 4,5-diallyl vinylene carbonate, vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate, 4-methyl-5-
Since vinyl ethylene carbonate, allyl ethylene carbonate, 4,5-diallyl ethylene carbonate, 4-methyl-5-allyl ethylene carbonate, 4-allyl-5-vinyl ethylene carbonate form a stable interface protective film, it is more preferable. Used.

The molecular weight of the unsaturated cyclic carbonate is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight is preferably 50 or more and 250 or less. If it is this range, it will be easy to ensure the solubility of the unsaturated cyclic carbonate with respect to a non-aqueous electrolyte solution, and the effect of this invention will fully be expressed easily. The molecular weight of the unsaturated cyclic carbonate is more preferably 80
It is above, More preferably, it is 150 or less. The production method of the unsaturated cyclic carbonate is not particularly limited, and can be produced by arbitrarily selecting a known method.

An unsaturated cyclic carbonate may be used individually by 1 type, or may have 2 or more types by arbitrary combinations and ratios. Moreover, the compounding quantity of unsaturated cyclic carbonate is not restrict | limited in particular, As long as the effect of this invention is not impaired remarkably, it is arbitrary. The amount of the unsaturated cyclic carbonate is 100% by mass in the non-aqueous electrolyte solution, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and further preferably 0.2% by mass or more. Moreover, preferably 5 mass% or less,
More preferably, it is 4 mass% or less, More preferably, it is 3 mass% or less. Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient cycle characteristics improving effect, and the high temperature storage characteristics are reduced, the amount of gas generated is increased, and the discharge capacity maintenance rate is reduced. Easy to avoid. On the other hand, if the amount is too small, the effect of the present invention may not be sufficiently exerted,
If the amount is too large, the resistance may increase and the output and load characteristics may deteriorate.

<Fluorinated unsaturated cyclic carbonate>
As the fluorinated cyclic carbonate, it is also preferable to use a cyclic carbonate having an unsaturated bond and a fluorine atom (hereinafter sometimes abbreviated as “fluorinated unsaturated cyclic carbonate”). If the number of fluorine atoms in the fluorinated unsaturated cyclic carbonate is 1 or more,
There is no particular limitation. Among them, the number of fluorine atoms is usually 6 or less, preferably 4 or less, and most preferably 1 or 2 fluorine atoms.

Examples of the fluorinated unsaturated cyclic carbonate include fluorinated vinylene carbonate derivatives, fluorinated ethylene carbonate derivatives substituted with an aromatic ring or a substituent having a carbon-carbon double bond.
As a fluorinated vinylene carbonate derivative, 4-fluoro vinylene carbonate,
Examples include 4-fluoro-5-methyl vinylene carbonate, 4-fluoro-5-phenyl vinylene carbonate, 4-allyl-5-fluoro vinylene carbonate, 4-fluoro-5-vinyl vinylene carbonate.

Examples of the fluorinated ethylene carbonate derivative substituted with an aromatic ring or a substituent having a carbon-carbon double bond include 4-fluoro-4-vinylethylene carbonate, 4-fluoro-
4-allylethylene carbonate, 4-fluoro-5-vinylethylene carbonate, 4
-Fluoro-5-allylethylene carbonate, 4,4-difluoro-4-vinylethylene carbonate, 4,4-difluoro-4-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate, 4,5-difluoro -4-allylethylene carbonate, 4-fluoro-4,5-divinylethylene carbonate, 4-fluoro-4
, 5-diallylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate, 4,5-difluoro-4,5-diallylethylene carbonate, 4-fluoro-4-phenylethylene carbonate, 4-fluoro-5 -Phenylethylene carbonate, 4,4-difluoro-5-phenylethylene carbonate, 4,5-difluoro-4-phenylethylene carbonate and the like.

Among them, particularly preferred fluorinated unsaturated cyclic carbonates for use in combination with a compound having a carbon-carbon triple bond include 4-fluorovinylene carbonate, 4-fluoro-5-
Methyl vinylene carbonate, 4-fluoro-5-vinyl vinylene carbonate, 4-allyl-5-fluoro vinylene carbonate, 4-fluoro-4-vinyl ethylene carbonate, 4-fluoro-4-allyl ethylene carbonate, 4-fluoro-5- Vinylethylene carbonate, 4-fluoro-5-allylethylene carbonate, 4,4-difluoro-4-vinylethylene carbonate, 4,4-difluoro-4-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate, 4,5-difluoro-
4-allylethylene carbonate, 4-fluoro-4,5-divinylethylene carbonate, 4-fluoro-4,5-diallylethylene carbonate, 4,5-difluoro-4,
5-Divinylethylene carbonate and 4,5-difluoro-4,5-diallylethylene carbonate are more preferably used because they form a stable interface protective film.

The molecular weight of the fluorinated unsaturated cyclic carbonate is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight is preferably 50 or more and 250 or less. If it is this range, it will be easy to ensure the solubility of the fluorinated cyclic carbonate with respect to a non-aqueous electrolyte solution, and the effect of this invention will be easy to be expressed. The production method of the fluorinated unsaturated cyclic carbonate is not particularly limited, and can be produced by arbitrarily selecting a known method. The molecular weight is more preferably 100 or more, and more preferably 200 or less.

A fluorinated unsaturated cyclic carbonate may be used individually by 1 type, and may have 2 or more types by arbitrary combinations and ratios. Moreover, the compounding quantity of a fluorinated unsaturated cyclic carbonate is not restrict | limited in particular, As long as the effect of this invention is not impaired remarkably, it is arbitrary. The compounding amount of the fluorinated unsaturated cyclic carbonate is usually 0.01% by mass or more, more preferably 0.1% by mass or more, further preferably 0.2% by mass or more, in 100% by mass of the nonaqueous electrolytic solution. Moreover, it is preferably 5% by mass or less, more preferably 4% by mass or less, and further preferably 3% by mass or less. Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient cycle characteristics improving effect, and the high temperature storage characteristics are reduced, the amount of gas generated is increased, and the discharge capacity maintenance rate is reduced. Easy to avoid. On the other hand, if the amount is too small, the effects of the present invention may not be sufficiently exhibited. If the amount is too large, the resistance may increase and the output and load characteristics may decrease.

<Overcharge prevention agent>
In the non-aqueous electrolyte solution of the present invention, an overcharge inhibitor can be used in order to effectively suppress battery explosion / ignition when the non-aqueous electrolyte secondary battery is in an overcharged state or the like. .
As an overcharge inhibitor, aromatic compounds such as biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, dibenzofuran; 2-fluorobiphenyl, o
-Partially fluorinated products of the above aromatic compounds such as cyclohexylfluorobenzene and p-cyclohexylfluorobenzene; 2,4-difluoroanisole, 2,5-difluoroanisole, 2,6-difluoroanisole, 3,5-difluoroanisole and the like And fluorine-containing anisole compounds. Of these, aromatic compounds such as biphenyl, alkylbiphenyl, terphenyl, terphenyl partially hydrogenated, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, and dibenzofuran are preferable. These may be used alone or in combination of two or more. When two or more kinds are used in combination, in particular, a combination of cyclohexylbenzene and t-butylbenzene or t-amylbenzene, biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, Using at least one selected from aromatic compounds not containing oxygen, such as t-amylbenzene, and at least one selected from oxygen-containing aromatic compounds such as diphenyl ether, dibenzofuran, and the like is an overcharge prevention property and a high temperature storage property. From the standpoint of balance.

The amount of the overcharge inhibitor is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The overcharge inhibitor is preferably 0.1% by mass or more and 5% by mass or less in 100% by mass of the non-aqueous electrolyte solution. If it is this range, it will be easy to fully express the effect of an overcharge inhibiting agent, and it will be easy to avoid the situation where the battery characteristics, such as a high temperature storage characteristic, fall. The overcharge inhibitor is more preferably 0.2% by mass or more, further preferably 0.3% by mass or more, particularly preferably 0.5% by mass or more, and more preferably 3% by mass or less, still more preferably. Is 2% by mass or less.

<Other auxiliaries>
Other known auxiliary agents can be used in the non-aqueous electrolyte solution of the present invention. Other auxiliaries include carbonate compounds such as erythritan carbonate, spiro-bis-dimethylene carbonate, methoxyethyl-methyl carbonate; succinic anhydride, glutaric anhydride, maleic anhydride, citraconic anhydride, glutaconic anhydride, anhydrous Carboxylic anhydrides such as itaconic acid, diglycolic anhydride, cyclohexanedicarboxylic anhydride, cyclopentanetetracarboxylic dianhydride and phenylsuccinic anhydride; 2,4,8,10-tetraoxaspiro [5.5 ] Spiro compounds such as undecane, 3,9-divinyl-2,4,8,10-tetraoxaspiro [5.5] undecane; ethylene sulfite, 1,3-propane sultone, 1-fluoro-1,3- Propane sultone, 2-fluoro-1,3-propane sultone, 3-ph Oro-1,3-propane sultone, 1-propene-1,3-sultone,
1-fluoro-1-propene-1,3-sultone, 2-fluoro-1-propene-1,3
-Sultone, 3-fluoro-1-propene-1,3-sultone, 1,4-butane sultone, 1-butene-1,4-sultone, 3-butene-1,4-sultone, methyl fluorosulfonate, fluorosulfone Sulfur-containing compounds such as ethyl acetate, methyl methanesulfonate, ethyl methanesulfonate, busulfan, sulfolene, diphenylsulfone, N, N-dimethylmethanesulfonamide, N, N-diethylmethanesulfonamide; 1-methyl-2-pyrrolidinone 1-methyl-2-piperidone, 3-methyl-2-oxazolidinone, 1,3-
Nitrogen-containing compounds such as dimethyl-2-imidazolidinone and N-methylsuccinimide; hydrocarbon compounds such as heptane, octane, nonane, decane, cycloheptane, and the like, such as fluorobenzene, difluorobenzene, hexafluorobenzene and benzotrifluoride Fluoroaromatic compounds and the like can be mentioned. These may be used alone or in combination of two or more. By adding these auxiliaries, capacity maintenance characteristics and cycle characteristics after high temperature storage can be improved.

The blending amount of other auxiliary agents is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The other auxiliary agent is preferably 0.01% by mass or more and 5% by mass or less in 100% by mass of the non-aqueous electrolyte solution. Within this range, the effects of other auxiliaries can be sufficiently exhibited, and it is easy to avoid a situation in which battery characteristics such as high-load discharge characteristics deteriorate.
The blending amount of other auxiliaries is more preferably 0.1% by mass or more, further preferably 0.2% by mass or more, more preferably 3% by mass or less, and further preferably 1% by mass or less. .

The non-aqueous electrolyte solution described above includes those existing inside the non-aqueous electrolyte battery according to the present invention. Specifically, the components of the non-aqueous electrolyte solution such as lithium salt, solvent, and auxiliary agent are separately synthesized, and the non-aqueous electrolyte solution is prepared from what is substantially isolated by the method described below. In the case of a nonaqueous electrolyte solution in a nonaqueous electrolyte battery obtained by pouring into a separately assembled battery, the components of the nonaqueous electrolyte solution of the present invention are individually placed in the battery, In order to obtain the same composition as the non-aqueous electrolyte solution of the present invention by mixing in a non-aqueous electrolyte battery, the compound constituting the non-aqueous electrolyte solution of the present invention is further generated in the non-aqueous electrolyte battery. The case where the same composition as the aqueous electrolyte is obtained is also included.

2. Separator In the non-aqueous electrolyte secondary battery of the present invention, a separator is interposed between the positive electrode and the negative electrode in order to prevent a short circuit. In this case, the nonaqueous electrolytic solution of the present invention is usually used by impregnating the separator.
The material and shape of the separator are not particularly limited, and known ones can be arbitrarily adopted as long as the effects of the present invention are not significantly impaired. Among them, the present invention is characterized by using a separator formed of a material that is stable with respect to the non-aqueous electrolyte solution of the present invention and having a polyolefin resin as a part of the constituent components. , Other resins,
Glass fiber, an inorganic substance, etc. can also be used. As the shape, it is preferable to use a porous sheet excellent in liquid retention or a non-woven fabric.

It is important that the separator used in the present invention has a polyolefin-based resin as a part of the constituent components. Specific examples of the polyolefin resin include polyethylene resin, polypropylene resin, 1-polymethylpentene, and polyphenylene sulfide.
Examples of polyethylene resins include low-density polyethylene, linear low-density polyethylene, linear ultra-low-density polyethylene, medium-density polyethylene, high-density polyethylene, and copolymers based on ethylene, that is, ethylene and propylene, butene -1, pentene-1, hexene-1, heptene-1, octene-1, etc., α-olefins having 3 to 10 carbon atoms; vinyl esters such as vinyl acetate and vinyl propionate; methyl acrylate, ethyl acrylate, methacryl A copolymer or multi-component copolymer with one or more comonomers selected from unsaturated carboxylic acid esters such as methyl acrylate and ethyl methacrylate, and unsaturated compounds such as conjugated and non-conjugated dienes, or The mixed composition is mentioned. The ethylene unit content of the ethylene polymer is usually more than 50% by mass.

Among these polyethylene resins, at least one polyethylene resin selected from low density polyethylene, linear low density polyethylene, and high density polyethylene is preferable, and high density polyethylene is most preferable.
Moreover, there is no restriction | limiting in particular in the polymerization catalyst of a polyethylene-type resin, Any things, such as a Ziegler type catalyst, a Phillips type catalyst, and a Kaminsky type catalyst, may be used. As a polymerization method of the polyethylene resin, there are a one-stage polymerization, a two-stage polymerization, or a multistage polymerization more than that, and any method of the polyethylene resin can be used.

The melt flow rate (MFR) of the polyethylene resin is not particularly limited, but usually the MFR is preferably 0.03 to 15 g / 10 minutes, preferably 0.3 to 10 g /
It is preferably 10 minutes. If the MFR is in the above range, the back pressure of the extruder does not become too high during the molding process and the productivity is excellent. The MFR in the present invention is based on JISK7210, and is a measured value under conditions of a temperature of 190 ° C. and a load of 2.16 kg.

The production method of the polyethylene resin is not particularly limited, and is a known polymerization method using a known olefin polymerization catalyst, for example, a multisite catalyst represented by a Ziegler-Natta type catalyst or a metallocene catalyst. A polymerization method using a single site catalyst may be mentioned.
Next, an example of a polypropylene resin will be described. The polypropylene resin in the present invention is homopolypropylene (propylene homopolymer), or propylene and ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene or 1-decene. And a random copolymer or a block copolymer with an α-olefin. Among these, when used for a battery separator, homopolypropylene is more preferably used from the viewpoint of mechanical strength.

The polypropylene resin preferably has an isotactic pentad fraction exhibiting stereoregularity of 80 to 99%, more preferably 83 to 98%, and still more preferably 85 to 97%. use. If the isotactic pentad fraction is too low,
The mechanical strength of the battery separator may be reduced. On the other hand, the upper limit of the isotactic pentad fraction is defined by the upper limit that can be obtained industrially at present, but this is not the case when a more regular resin is developed in the industrial level in the future. is not.
The isotactic pentad fraction is a three-dimensional structure in which five methyl groups that are side chains are located in the same direction with respect to the main chain of carbon-carbon bonds composed of arbitrary five consecutive propylene units. Or the ratio is meant. Signal assignment of the methyl group region is as follows. Za
mbellietatal. (Macromol. 8, 687 (1975)).

In addition, the polypropylene resin has a Mw / Mn which is a parameter indicating a molecular weight distribution of 1.
It is preferably 5 to 10.0. More preferably, it is 2.0-8.0, More preferably, it is 2.
. What is 0-6.0 is used. This means that the smaller the Mw / Mn, the narrower the molecular weight distribution. However, if the Mw / Mn is less than 1.5, problems such as a decrease in extrusion moldability occur, and it is difficult to produce industrially. There are many cases. On the other hand, when Mw / Mn exceeds 10.0, the low molecular weight component increases, and the mechanical strength of the obtained battery separator tends to decrease.
Mw / Mn is obtained by GPC (gel per emission chromatography) method.

Further, the melt flow rate (MFR) of the polypropylene resin is not particularly limited, but usually, the MFR is preferably 0.1 to 15 g / 10 min, and preferably 0.5 to 10
More preferably, it is g / 10 minutes. When the MFR is less than 0.1 g / 10 minutes, the melt viscosity of the resin during the molding process is high, and the productivity is lowered. On the other hand, when it exceeds 15 g / 10 minutes, practical problems such as insufficient strength of the obtained battery separator tend to occur. MFR is JI
In accordance with SK7210, measurement is performed under conditions of a temperature of 230 ° C. and a load of 2.16 kg.

Examples of polypropylene resins include trade names “NOVATEC PP” and “WINTEC”.
(Manufactured by Nippon Polypro), "Versify""Notio""ToughmerXR" (Mitsui Chemicals), "Zeras""Thermorun" (Mitsubishi Chemical), "Sumitomo Noblen""ToughSelenium" (
Sumitomo Chemical Co., Ltd.), “Prime TPO” (Prime Polymer Co., Ltd.), “Adflex”, “A
dsyl "" HMS-PP (PF814) "(manufactured by Sun Allomer)," Inspire "(
Commercially available products such as Dow Chemical Co.) can be used.

As materials for other resins and glass fiber separators, for example, aromatic polyamide, polytetrafluoroethylene, polyethersulfone, glass filter, and the like can be used in combination with the polyolefin resin. These materials may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
In addition, separators that contain polyolefin resin as a component include polyolefin resin that contains elements such as Al and Mg that remain due to the use of Ziegler-Natta catalyst in the production process. Since elements such as Ca and Zn remain due to the use of a metal soap introduced as a neutralizing agent for antioxidants, it usually contains calcium element or Al element.

In the present invention, the concentration of the calcium element contained in the separator is 300 ppm or less. Above all, the concentration of calcium element contained in the separator is 150 pp.
m or less, more preferably 100 ppm or less, 50 ppm
The following is more preferable.
In the present invention, the concentration of the aluminum element contained in the separator is 150 ppm or less. Above all, the concentration of aluminum contained in the separator is 50
It is preferably at most ppm. In addition, it is preferable to adjust the concentration of the aluminum element as described above together with the case where the concentration of the calcium element contained in the separator is set to a specific amount or less.

Here, it is preferable that the separator used in the present invention contains an antioxidant so that the separator is not easily oxidized even in a storage state before battery assembly. Antioxidants include phenolic antioxidants such as “IRGANOX” (manufactured by Ciba Specialty Chemicals), “Yoshinox” (manufactured by API Corporation), and “IRGASTAB” (manufactured by Ciba Specialty Chemicals). Amine antioxidants such as “IRGAFOS” (manufactured by Ciba Specialty Chemicals), phosphorous antioxidants such as “Smilizer” (manufactured by Sumitomo Chemical Co., Ltd.), and the like.

It is also preferred that a neutralizing agent is contained in order to neutralize such an antioxidant. A metal soap such as calcium stearate is preferably used as the neutralizing agent.
Here, the present inventors, when the compound having a carbon-carbon triple bond contained in the non-aqueous electrolyte of the present invention contains a polymerization catalyst residue, an antioxidant and its neutralizer in the separator In addition, when the content thereof is too large, it has been found that the compound having a carbon-carbon triple bond tends to inhibit the “characteristic of suitably forming an interface protective film with an electrode”. By using it in combination with a separator whose concentration of the residue, antioxidant and its neutralizing agent is less than a specific amount, a compound having a carbon-carbon triple bond “properly forms an interface protective coating with an electrode” "

When a battery is prepared using a separator in which such a polymerization catalyst residue, an antioxidant or its neutralizer is excessively left or added, the polymerization catalyst residue, the antioxidant or its neutralizer is used as an electrode. It causes side reactions such as decomposition or precipitation on the surface, reducing the charge capacity or discharge capacity, increasing the battery resistance, generating a large amount of decomposition gas during battery operation, and swelling the battery, Cycle capacity may be reduced.

A compound containing a carbon-carbon triple bond has a highly developed protective film derived from polymerization by a compound containing a carbon-carbon triple bond on the electrode surface, and suppresses side decomposition reactions caused by electrolyte components other than the above. This has the effect of improving the durability characteristics of the battery. However, if the concentration of the polymerization catalyst residue, antioxidant or its neutralizer is too high, the polymerization catalyst residue, antioxidant or its neutralizer will protect the compound containing the carbon-carbon triple bond. A side reaction occurs preferentially on the electrode surface over the formation of the film, and as a result, it becomes difficult for the compound containing a carbon-carbon triple bond to exert its inherent effect.

Thus, by effectively functioning a compound containing a carbon-carbon triple bond, the initial efficiency,
In order to obtain a battery having high durability such as cycle characteristics and storage characteristics, it is preferable that the polymerization catalyst residue, the antioxidant and the neutralizing agent are less, so that the preferable concentration as described above can be defined. .
The thickness of the separator is arbitrary, but is usually 1 μm or more, preferably 5 μm or more, and 8
More preferably, it is 50 μm or less, preferably 40 μm or less,
More preferably, it is 30 μm or less. If the separator is too thin than the above range, the insulating properties and mechanical strength may decrease. On the other hand, if it is thicker than the above range, not only the battery performance such as the rate characteristic may be lowered, but also the energy density of the whole non-aqueous electrolyte secondary battery may be lowered.

Furthermore, when a porous material such as a porous sheet or nonwoven fabric is used as the separator, the porosity of the separator is arbitrary, but is usually 20% or more, preferably 35% or more, and 45%
The above is more preferable, and it is usually 90% or less, preferably 85% or less, and more preferably 75% or less. If the porosity is too smaller than the above range, the membrane resistance tends to increase and the rate characteristics tend to deteriorate. Moreover, when larger than the said range, it exists in the tendency for the mechanical strength of a separator to fall and for insulation to fall.

The average pore diameter of the separator is also arbitrary, but is usually 0.5 μm or less and 0.2 μm.
The following is preferable and is usually 0.05 μm or more. If the average pore diameter exceeds the above range, a short circuit tends to occur. On the other hand, below the above range, the film resistance may increase and the rate characteristics may deteriorate.
On the other hand, as inorganic materials, for example, oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, and sulfates such as barium sulfate and calcium sulfate are used. Used.

As the form, a thin film shape such as a non-woven fabric, a woven fabric, or a microporous film is used. In the thin film shape, those having a pore diameter of 0.01 to 1 μm and a thickness of 5 to 50 μm are preferably used.
In addition to the above-mentioned independent thin film shape, a separator formed by forming a composite porous layer containing the inorganic particles on the surface layer of the positive electrode and / or the negative electrode using a resin binder can be used. For example, a porous layer may be formed by using alumina particles having a 90% particle size of less than 1 μm on both surfaces of the positive electrode and using a fluororesin as a binder.

3. Negative electrode The negative electrode active material used for the negative electrode is described below. The negative electrode active material is not particularly limited as long as it can electrochemically occlude and release lithium ions. As a specific example,
Examples thereof include carbonaceous materials, alloy materials, and lithium-containing metal composite oxide materials. These are 1
You may use a seed | species independently and may use it combining 2 or more types arbitrarily.

<Negative electrode active material>
Examples of the negative electrode active material include carbonaceous materials, alloy materials, lithium-containing metal composite oxide materials, and the like.
As a carbonaceous material used as a negative electrode active material,
(1) natural graphite,
(2) a carbonaceous material obtained by heat-treating an artificial carbonaceous material and an artificial graphite material at least once in the range of 400 to 3200 ° C;
(3) a carbonaceous material in which the negative electrode active material layer is made of carbonaceous materials having at least two or more different crystallinities and / or has an interface in contact with the different crystalline carbonaceous materials,
(4) A carbonaceous material in which the negative electrode active material layer is made of carbonaceous materials having at least two or more different orientations and / or has an interface in contact with the carbonaceous materials having different orientations,
Is preferably a good balance between initial irreversible capacity and high current density charge / discharge characteristics. Moreover, the carbonaceous materials (1) to (4) may be used alone or in combination of two or more in any combination and ratio.

Examples of the artificial carbonaceous material and artificial graphite material of (2) above include natural graphite, coal-based coke, petroleum-based coke, coal-based pitch, petroleum-based pitch, those obtained by oxidizing these pitches, needle coke, pitch coke and Carbon materials that are partially graphitized, furnace black, acetylene black, organic pyrolysis products such as pitch-based carbon fibers, carbonizable organic materials and their carbides, or carbonizable organic materials are benzene, toluene, xylene, quinoline And a solution dissolved in a low-molecular organic solvent such as n-hexane, and carbides thereof.

As an alloy material used as the negative electrode active material, as long as lithium can be occluded / released, lithium alone, simple metals and alloys forming lithium alloys, or oxides, carbides, nitrides, silicides, sulfides thereof Any of compounds such as products or phosphides may be used and is not particularly limited. The single metal and alloy forming the lithium alloy are preferably materials containing group 13 and group 14 metal / metalloid elements (that is, excluding carbon), more preferably aluminum, silicon and tin (hereinafter referred to as “ Simple metals) and alloys or compounds containing these atoms (sometimes abbreviated as “specific metal elements”). These may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

As a negative electrode active material having at least one kind of atom selected from a specific metal element, a metal simple substance of any one specific metal element, an alloy composed of two or more specific metal elements, one type or two or more specific types An alloy comprising a metal element and one or more other metal elements, and 1
Examples thereof include compounds containing a seed or two or more kinds of specific metal elements, and complex compounds such as oxides, carbides, nitrides, silicides, sulfides or phosphides of the compounds. By using these simple metals, alloys or metal compounds as the negative electrode active material, the capacity of the battery can be increased.

In addition, a compound in which these complex compounds are complexly bonded to several kinds of elements such as a simple metal, an alloy, or a nonmetallic element is also included. Specifically, for example, in silicon and tin, an alloy of these elements and a metal that does not operate as a negative electrode can be used. For example, in the case of tin, a complex compound containing 5 to 6 kinds of elements in combination with a metal that acts as a negative electrode other than tin and silicon, a metal that does not operate as a negative electrode, and a nonmetallic element may be used. it can.

Among these negative electrode active materials, since the capacity per unit mass is large when a battery is formed, any one simple metal of a specific metal element, an alloy of two or more specific metal elements, oxidation of a specific metal element In particular, silicon and / or tin metal simple substance, alloy, oxide, carbide, nitride and the like are preferable from the viewpoint of capacity per unit mass and environmental load.

The lithium-containing metal composite oxide material used as the negative electrode active material is not particularly limited as long as it can occlude and release lithium, but a material containing titanium and lithium is preferable from the viewpoint of high current density charge / discharge characteristics, A lithium-containing composite metal oxide material containing titanium is more preferable, and a composite oxide of lithium and titanium (hereinafter sometimes abbreviated as “lithium titanium composite oxide”). That is, it is particularly preferable to use a lithium titanium composite oxide having a spinel structure in a negative electrode active material for a non-aqueous electrolyte battery because the output resistance is greatly reduced.

In addition, lithium and titanium of the lithium titanium composite oxide are other metal elements such as Na.
Also preferable are those substituted with at least one element selected from the group consisting of K, Co, Al, Fe, Ti, Mg, Cr, Ga, Cu, Zn and Nb.
The metal oxide is a lithium titanium composite oxide represented by the general formula (A). In the general formula (A), 0.7 ≦ x ≦ 1.5, 1.5 ≦ y ≦ 2.3, It is preferable that 0 ≦ z ≦ 1.6 because the structure upon doping and dedoping of lithium ions is stable.

Li _x Ti _y M _z O ₄ (A)
[In general formula (A), M is Na, K, Co, Al, Fe, Ti, Mg, Cr, Ga, Cu.
Represents at least one element selected from the group consisting of Zn and Nb. ]
Among the compositions represented by the general formula (A),
(A) 1.2 ≦ x ≦ 1.4, 1.5 ≦ y ≦ 1.7, z = 0
(B) 0.9 ≦ x ≦ 1.1, 1.9 ≦ y ≦ 2.1, z = 0
(C) 0.7 ≦ x ≦ 0.9, 2.1 ≦ y ≦ 2.3, z = 0
This structure is particularly preferable because of a good balance of battery performance.
A particularly preferred representative composition of the above compounds is Li _4/3 Ti _5/3 O ₄ , (a), (
In b), Li ₁ Ti ₂ O ₄ , and in (c), Li _4/5 Ti _11/5 O ₄ .
As for the structure of Z ≠ 0, for example, Li _4/3 Ti _4/3 Al _1/3 O ₄ is preferable.

<Physical properties of carbonaceous materials>
When using a carbonaceous material as a negative electrode active material, it is desirable to have the following physical properties.
(X-ray parameters)
The d value (interlayer distance) of the lattice plane (002 plane) determined by X-ray diffraction by the Gakushin method of carbonaceous materials is preferably 0.335 nm or more, and is usually 0.360 nm or less.
. 350 nm or less is preferable and 0.345 nm or less is more preferable. Further, the crystallite size (Lc) of the carbonaceous material obtained by X-ray diffraction by the Gakushin method is preferably 1.0 nm or more, and more preferably 1.5 nm or more.

(Volume-based average particle size)
The volume-based average particle diameter of the carbonaceous material is a volume-based average particle diameter (median diameter) obtained by a laser diffraction / scattering method, and is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and 7 μm. The above is particularly preferable, and is usually 100 μm or less, 50
μm or less is preferable, 40 μm or less is more preferable, 30 μm or less is more preferable, and 2 μm or less is preferable.
5 μm or less is particularly preferable.

If the volume-based average particle size is below the above range, the irreversible capacity may increase, leading to loss of initial battery capacity. On the other hand, when the above range is exceeded, when an electrode is produced by coating, an uneven coating surface tends to be formed, which may be undesirable in the battery production process.
The volume-based average particle size is measured by dispersing carbon powder in a 0.2% by weight aqueous solution (about 10 mL) of polyoxyethylene (20-mer) sorbitan monolaurate, which is a surfactant, and using a laser diffraction / scattering method. This is performed using a particle size distribution meter (LA-700, manufactured by Horiba, Ltd.). The median diameter determined by the measurement is defined as the volume-based average particle diameter of the carbonaceous material of the present invention.

(Raman R value, Raman half width)
The Raman R value of the carbonaceous material is a value measured using an argon ion laser Raman spectrum method, and is usually 0.01 or more, preferably 0.03 or more, more preferably 0.1 or more, and usually 1.5 or less, preferably 1.2 or less, more preferably 1 or less, and particularly preferably 0.5 or less.

When the Raman R value is below the above range, the crystallinity of the particle surface becomes too high, and there are cases where the number of sites where Li enters between layers decreases with charge / discharge. That is, charge acceptance may be reduced. In addition, when the negative electrode is densified by applying it to the current collector and then pressing it, the crystals are likely to be oriented in a direction parallel to the electrode plate, which may lead to a decrease in load characteristics. In particular, when the Raman R value is 0.1 or more, a suitable film can be formed on the surface of the negative electrode, whereby storage characteristics, cycle characteristics, and load characteristics can be improved.

On the other hand, if it exceeds the above range, the crystallinity of the particle surface is lowered, the reactivity with the non-aqueous electrolyte is increased, and the efficiency may be lowered and the gas generation may be increased.
Further, the Raman half-width in the vicinity of 1580 cm ^{−1 of the} carbonaceous material is not particularly limited, but is usually 10 cm ⁻¹ or more, preferably 15 cm ⁻¹ or more, and usually 100 cm ⁻¹ or less, and 80 cm ⁻¹ or less. Preferably, 60 cm ⁻¹ or less is more preferable, and 40 cm ^−
1 or less is particularly preferable.

If the Raman half width is less than the above range, the crystallinity of the particle surface becomes too high, and there are cases where the number of sites where Li enters between layers decreases with charge and discharge. That is, charge acceptance may be reduced. In addition, when the negative electrode is densified by applying it to the current collector and then pressing it, the crystals are likely to be oriented in a direction parallel to the electrode plate, which may lead to a decrease in load characteristics. on the other hand,
When the above range is exceeded, the crystallinity of the particle surface is lowered, the reactivity with the non-aqueous electrolyte is increased, and the efficiency may be lowered and the gas generation may be increased.

The measurement of the Raman spectrum, using a Raman spectrometer (manufactured by JASCO Corporation Raman spectrometer), the sample is naturally dropped into the measurement cell and filled, and while irradiating the sample surface in the cell with argon ion laser light, This is done by rotating the cell in a plane perpendicular to the laser beam. Regarding the obtained Raman spectrum, the intensity I _A of the peak P _A near 1580 cm ⁻¹ and 1
The intensity _{I B} of 360 cm ^-1 vicinity of the peak _{P B} is measured, the intensity ratio _{R (R = I B / I} A
) Is calculated. The Raman R value calculated by the measurement is defined as the Raman R value of the carbonaceous material of the present invention. Further, the half width of the peak P _A in the vicinity of 1580 cm ^-1 of the resulting Raman spectrum was measured, which is defined as the Raman half-value width of the carbonaceous material of the present invention.

Moreover, said Raman measurement conditions are as follows.
Argon ion laser wavelength: 514.5nm
-Laser power on the sample: 15-25 mW
・ Resolution: 10-20cm ^-1
Measurement range: 1100 cm ^{−1 to} 1730 cm ⁻¹
・ Raman R value, Raman half-width analysis: Background processing ・ Smoothing processing: Simple average, 5 points of convolution

(BET specific surface area)
BET specific surface area of the carbonaceous material is a value of the measured specific surface area using the BET method is usually 0.1 m ² · ^{g -1} or more, 0.7 m ² · ^{g -1} or more, 1. 0m ²・ g ^−
1 or more is more preferable, 1.5 m ² · g ⁻¹ or more is particularly preferable, and usually 100 m.
And a ² · ^{g -1} or less, preferably ^{25 m} 2 · ^{g -1} or less, ^{15 m} 2 · ^{g -1} and more preferably less, ^{10 m} 2 · ^{g -1} or less are especially preferred.

When the value of the BET specific surface area is less than this range, the acceptability of lithium tends to deteriorate during charging when it is used as a negative electrode material, lithium tends to precipitate on the electrode surface, and stability may be lowered. On the other hand, if it exceeds this range, when used as a negative electrode material, the reactivity with the non-aqueous electrolyte increases, gas generation tends to increase, and a preferable battery may be difficult to obtain.

The specific surface area was measured by the BET method using a surface area meter (a fully automated surface area measuring device manufactured by Okura Riken), preliminarily drying the sample at 350 ° C. for 15 minutes under nitrogen flow, Using a nitrogen helium mixed gas accurately adjusted so that the value of the relative pressure becomes 0.3, the nitrogen adsorption BET one-point method by the gas flow method is used. The specific surface area determined by the measurement is defined as the BET specific surface area of the carbonaceous material of the present invention.

(Roundness)
When the circularity is measured as the degree of the sphere of the carbonaceous material, it is preferably within the following range. The circularity is “circularity = (peripheral length of an equivalent circle having the same area as the particle projection shape) /
(Actual perimeter of the projected particle shape) ”, and when the circularity is 1, a theoretical sphere is obtained.
The degree of circularity of particles having a carbonaceous material particle size in the range of 3 to 40 μm is preferably closer to 1,
Moreover, 0.1 or more is preferable, and 0.5 or more is preferable, 0.8 or more is more preferable, 0.85 or more is further more preferable, and 0.9 or more is particularly preferable. High current density charge / discharge characteristics improve as the degree of circularity increases. Therefore, when the circularity is less than the above range, the filling property of the negative electrode active material is lowered, the resistance between particles is increased, and the high current density charge / discharge characteristics may be lowered for a short time.

The circularity is measured using a flow type particle image analyzer (FPIA manufactured by Sysmex Corporation). About 0.2 g of a sample is dispersed in a 0.2% by mass aqueous solution (about 50 mL) of polyoxyethylene (20) sorbitan monolaurate, which is a surfactant, and an output of 28 kHz ultrasonic waves is output 60.
After irradiating with W for 1 minute, the detection range is specified as 0.6 to 400 μm, and the measurement is performed on particles having a particle size in the range of 3 to 40 μm. The circularity determined by the measurement is defined as the circularity of the carbonaceous material of the present invention.

The method for improving the circularity is not particularly limited, but a sphere-shaped sphere is preferable because the shape of the interparticle void when the electrode body is formed is preferable. Examples of spheroidizing treatment include a method of mechanically approaching a sphere by applying a shearing force and a compressive force, a mechanical / physical processing method of granulating a plurality of fine particles by the binder or the adhesive force of the particles themselves, etc. Is mentioned.

(Tap density)
The tap density of the carbonaceous material is usually 0.1 g · cm ⁻³ or more, and 0.5 g · cm ^−3.
The above is preferable, 0.7 g · cm ⁻³ or more is more preferable, 1 g · cm ⁻³ or more is particularly preferable, 2 g · cm ⁻³ or less is preferable, 1.8 g · cm ⁻³ or less is more preferable, 1 It is particularly preferably not more than .6 g · cm ⁻³ . When the tap density is below the above range, the packing density is difficult to increase when used as a negative electrode, and a high-capacity battery may not be obtained. On the other hand, when the above range is exceeded, there are too few voids between particles in the electrode, it is difficult to ensure conductivity between the particles, and it may be difficult to obtain preferable battery characteristics.

The tap density is measured by passing through a sieve having an opening of 300 μm, dropping the sample onto a 20 cm ³ tapping cell and filling the sample to the upper end surface of the cell, and then measuring a powder density measuring device (for example, manufactured by Seishin Enterprise Co., Ltd.). Tap tapping with a stroke length of 10 mm
This is performed 0 times, and the tap density is calculated from the volume at that time and the mass of the sample. The tap density calculated by the measurement is defined as the tap density of the carbonaceous material of the present invention.

(Orientation ratio)
The orientation ratio of the carbonaceous material is usually 0.005 or more, preferably 0.01 or more,
It is more preferably 15 or more, and usually 0.67 or less. When the orientation ratio is below the above range, the high-density charge / discharge characteristics may deteriorate. The upper limit of the above range is the theoretical upper limit value of the orientation ratio of the carbonaceous material.

The orientation ratio is measured by X-ray diffraction after pressure-molding the sample. 0.47 g of sample diameter 1
X-ray diffraction is measured by setting a molded body obtained by filling a molding machine of 7 mm and compressing at 58.8 MN · m ^{-2 so} that it is flush with the surface of the measurement sample holder. . From the (110) diffraction and (004) diffraction peak intensities of the obtained carbon, (110) diffraction peak intensity / (
004) Calculate the ratio represented by the diffraction peak intensity. The orientation ratio calculated by the measurement is defined as the orientation ratio of the carbonaceous material of the present invention.

The X-ray diffraction measurement conditions are as follows. “2θ” indicates a diffraction angle.
・ Target: Cu (Kα ray) graphite monochromator ・ Slit:
Divergence slit = 0.5 degree Light receiving slit = 0.15 mm
Scattering slit = 0.5 degree / measurement range and step angle / measurement time:
(110) plane: 75 degrees ≦ 2θ ≦ 80 degrees 1 degree / 60 seconds (004) plane: 52 degrees ≦ 2θ ≦ 57 degrees 1 degree / 60 seconds

(Aspect ratio (powder))
The aspect ratio of the carbonaceous material is usually 1 or more and usually 10 or less, preferably 8 or less, and more preferably 5 or less. If the aspect ratio exceeds the above range, streaking or a uniform coated surface cannot be obtained when forming an electrode plate, and the high current density charge / discharge characteristics may deteriorate. In addition,
The lower limit of the above range is the theoretical lower limit value of the aspect ratio of the carbonaceous material.

The aspect ratio is measured by magnifying and observing the carbonaceous material particles with a scanning electron microscope. Carbonaceous material particles when three-dimensional observation is performed by selecting arbitrary 50 graphite particles fixed to the end face of a metal having a thickness of 50 μm or less and rotating and tilting the stage on which the sample is fixed. The longest diameter A and the shortest diameter B orthogonal thereto are measured, and the average value of A / B is obtained. The aspect ratio (A / B) obtained by the measurement is defined as the aspect ratio of the carbonaceous material of the present invention.

<Configuration and production method of negative electrode>
Any known method can be used for producing the electrode as long as the effects of the present invention are not significantly impaired. For example, it is formed by adding a binder, a solvent, and, if necessary, a thickener, a conductive material, a filler, etc. to a negative electrode active material to form a slurry, which is applied to a current collector, dried and then pressed. Can do.
In addition, when using an alloy-based material, by techniques such as vapor deposition, sputtering, plating,
A method of forming a thin film layer (negative electrode active material layer) containing the above-described negative electrode active material is also used.

(Current collector)
As the current collector for holding the negative electrode active material, a known material can be arbitrarily used. Examples of the current collector for the negative electrode include metal materials such as aluminum, copper, nickel, stainless steel, and nickel-plated steel. Copper is particularly preferable from the viewpoint of ease of processing and cost.
In addition, the shape of the current collector may be, for example, a metal foil, a metal cylinder, a metal coil, a metal plate, a metal thin film, an expanded metal, a punch metal, a foam metal, or the like when the current collector is a metal material. Among them, a metal thin film is preferable, a copper foil is more preferable, and a rolled copper foil by a rolling method and an electrolytic copper foil by an electrolytic method are more preferable, and both can be used as a current collector.
The thickness of the current collector is usually 1 μm or more, preferably 5 μm or more, and is usually 100 μm or less, preferably 50 μm or less. This is because if the thickness of the negative electrode current collector is too thick, the capacity of the entire battery may be too low, and conversely if it is too thin, handling may be difficult.

(Thickness ratio between current collector and negative electrode active material layer)
The ratio of the thickness of the current collector to the negative electrode active material layer is not particularly limited, but the value of “(the thickness of the negative electrode active material layer on one side immediately before the nonaqueous electrolyte injection) / (thickness of the current collector)” However, 150 or less is preferable, 20 or less is more preferable, 10 or less is particularly preferable, 0.1 or more is preferable, 0.4 or more is more preferable, and 1 or more is particularly preferable. When the ratio of the thickness of the current collector to the negative electrode active material layer exceeds the above range, the current collector may generate heat due to Joule heat during high current density charge / discharge. On the other hand, below the above range, the volume ratio of the current collector to the negative electrode active material increases, and the battery capacity may decrease.

(Binder)
The binder for binding the negative electrode active material is not particularly limited as long as it is a material that is stable with respect to the non-aqueous electrolyte solution and the solvent used in manufacturing the electrode.
Specific examples include resin-based polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, polyimide, cellulose, and nitrocellulose; SBR (styrene-butadiene rubber), isoprene rubber, butadiene rubber, fluorine rubber, Rubber polymers such as NBR (acrylonitrile / butadiene rubber) and ethylene / propylene rubber; styrene / butadiene / styrene block copolymer or hydrogenated product thereof; EPDM (ethylene / propylene / diene terpolymer), styrene / Thermoplastic elastomeric polymers such as ethylene / butadiene / styrene copolymers, styrene / isoprene / styrene block copolymers or hydrogenated products thereof; syndiotactic-1,2-
Soft resin polymers such as polybutadiene, polyvinyl acetate, ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer; polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene Fluorine polymers such as ethylene copolymers; polymer compositions having alkali metal ion (especially lithium ion) ion conductivity, and the like. These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios.

The ratio of the binder to the negative electrode active material is preferably 0.1% by mass or more, 0.5% by mass
The above is more preferable, 0.6% by mass or more is particularly preferable, 20% by mass or less is preferable, 15% by mass or less is more preferable, 10% by mass or less is further preferable, and 8% by mass or less is particularly preferable. When the ratio of the binder with respect to a negative electrode active material exceeds the said range, the binder ratio from which the amount of binders does not contribute to battery capacity may increase, and the fall of battery capacity may be caused. On the other hand, below the above range, the strength of the negative electrode may be reduced.

In particular, when a rubbery polymer typified by SBR is contained as a main component, the ratio of the binder to the negative electrode active material is usually 0.1% by mass or more, preferably 0.5% by mass or more, and 0 .6% by mass or more is more preferable, and is usually 5% by mass or less, preferably 3% by mass or less, and more preferably 2% by mass or less. When the main component contains a fluorine-based polymer typified by polyvinylidene fluoride, the ratio to the negative electrode active material is usually 1% by mass or more, preferably 2% by mass or more, and more preferably 3% by mass or more. It is preferably 15% by mass or less, preferably 10% by mass or less, and more preferably 8% by mass or less.

(Slurry forming solvent)
The solvent for forming the slurry is not particularly limited as long as it is a solvent capable of dissolving or dispersing the negative electrode active material, the binder, and the thickener and conductive material used as necessary. Alternatively, either an aqueous solvent or an organic solvent may be used.
Examples of the aqueous solvent include water and alcohol. Examples of the organic solvent include N-methylpyrrolidone (NMP), dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, N, N- Examples include dimethylaminopropylamine, tetrahydrofuran (THF), toluene, acetone, diethyl ether, dimethylacetamide, hexamethylphosphalamide, dimethyl sulfoxide, benzene, xylene, quinoline, pyridine, methylnaphthalene, hexane, and the like.
In particular, when an aqueous solvent is used, it is preferable to add a dispersant or the like in addition to the thickener and slurry it using a latex such as SBR. In addition, these solvents may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and a ratio.

(Thickener)
A thickener is usually used to adjust the viscosity of the slurry. The thickener is not particularly limited, and specific examples include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and salts thereof. These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios.

Further, when using a thickener, the ratio of the thickener to the negative electrode active material is usually 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 0.6% by mass or more, Moreover, it is 5 mass% or less normally, 3 mass% or less is preferable, and 2 mass% or less is more preferable.
When the ratio of the thickener to the negative electrode active material is less than the above range, applicability may be significantly reduced. Moreover, when it exceeds the said range, the ratio of the negative electrode active material which occupies for a negative electrode active material layer will fall, and the problem that the capacity | capacitance of a battery falls and the resistance between negative electrode active materials may increase.

(Electrode density)
The electrode structure when the negative electrode active material is made into an electrode is not particularly limited, but the density of the negative electrode active material present on the current collector is preferably 1 g · cm ⁻³ or more, and 1.2 g · cm ⁻³ or more. but more preferably, particularly preferably 1.3 g · ^{cm -3} or more, preferably 2.2 g · ^{cm -3} or less, more preferably 2.1 g · ^{cm -3} or less, 2.0 g · ^{cm -3} or less Further preferred is 1.9 g · cm ⁻³ or less. When the density of the negative electrode active material existing on the current collector exceeds the above range, the negative electrode active material particles are destroyed, and the initial irreversible capacity increases or non-aqueous system near the current collector / negative electrode active material interface. There is a case where high current density charge / discharge characteristics are deteriorated due to a decrease in permeability of the electrolytic solution. On the other hand, if the amount is less than the above range, the conductivity between the negative electrode active materials decreases, the battery resistance increases, and the capacity per unit volume may decrease.

(Thickness of negative electrode plate)
The thickness of the negative electrode plate is designed according to the positive electrode plate to be used, and is not particularly limited. However, the thickness of the composite layer obtained by subtracting the thickness of the metal foil of the core is usually 15 μm or more, preferably 20 μm.
m or more, more preferably 30 μm or more, and usually 300 μm or less, preferably 280 μm
m or less, more preferably 250 μm or less.

(Surface coating of negative electrode plate)
Moreover, you may use what adhered the substance of the composition different from this to the surface of the said negative electrode plate. Surface adhering substances include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate And sulfates such as aluminum sulfate and carbonates such as lithium carbonate, calcium carbonate and magnesium carbonate.

4). Positive electrode <Positive electrode active material>
The positive electrode active material used for the positive electrode is described below.
(composition)
The positive electrode active material is not particularly limited as long as it can electrochemically occlude and release lithium ions. For example, a material containing lithium and at least one transition metal is preferable. Specific examples include lithium transition metal composite oxides and lithium-containing transition metal phosphate compounds.

As the transition metal of the lithium transition metal composite oxide, V, Ti, Cr, Mn, Fe, Co,
Ni, Cu and the like are preferable. Specific examples include lithium / cobalt composite oxides such as LiCoO ₂ , lithium / nickel composite oxides such as LiNiO ₂ , LiMnO ₂ , and LiMn ₂ O _4.
, Li ₂ MnO _{4 and} other lithium-manganese composite oxides, and some of the transition metal atoms that are the main components of these lithium transition metal composite oxides are Na, K, B, F, Al, Ti, V, Cr, Mn
Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn,
Examples thereof include those substituted with other elements such as W. Specific examples of the substituted one include, for example, LiNi _0.5 Mn _0.5 O ₂ , LiNi _0.85 Co _0.10 Al _0.05 O ₂ ,
LiNi _0.33 Co _0.33 Mn _0.33 O ₂ , LiNi _0.45 Co _0.10 Al _{0
. 45 O 2, LiMn 1.8 Al 0.2} O 4, LiMn 1.5 Ni 0.5 O 4 and the like.

As transition metals of lithium-containing transition metal phosphate compounds, V, Ti, Cr, Mn, Fe
, Co, Ni, Cu and the like are preferable, and specific examples include, for example, LiFePO ₄ , Li ₃ F
e ₂ (PO ₄ ) ₃ , iron phosphates such as LiFeP ₂ O ₇ , cobalt phosphates such as LiCoPO ₄ , and some of the transition metal atoms that are the main components of these lithium transition metal phosphate compounds are Al,
Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Nb
And those substituted with other elements such as Si.

In addition, it is preferable to include lithium phosphate in the positive electrode active material because continuous charge characteristics are improved. Although there is no restriction | limiting in the use of lithium phosphate, It is preferable to mix and use the said positive electrode active material and lithium phosphate. The lower limit of the amount of lithium phosphate used is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and still more preferably 0.5% by mass with respect to the total of the positive electrode active material and lithium phosphate. %, And the upper limit is preferably 10% by mass or less, more preferably 8% by mass or less, and further preferably 5% by mass or less.

(Surface coating)
Moreover, you may use what the substance of the composition different from this adhered to the surface of the said positive electrode active material. Surface adhering substances include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate And sulfates such as aluminum sulfate, carbonates such as lithium carbonate, calcium carbonate, and magnesium carbonate, and carbon.

These surface adhering substances are, for example, dissolved or suspended in a solvent and impregnated and added to the positive electrode active material,
According to a method of drying, a method in which a surface adhering substance precursor is dissolved or suspended in a solvent and impregnated and added to the positive electrode active material, and then reacted by heating, a method of adding to the positive electrode active material precursor and firing simultaneously, etc. It can be made to adhere to the positive electrode active material surface. In addition, when making carbon adhere, the method of making carbonaceous adhere mechanically later in the form of activated carbon etc. can also be used, for example.

The amount of the surface adhering substance is a mass with respect to the positive electrode active material, and the lower limit is preferably 0.8.
1 ppm or more, more preferably 1 ppm or more, more preferably 10 ppm or more, and the upper limit is preferably 20% or less, more preferably 10% or less, and even more preferably 5% or less. The surface adhering substance can suppress the oxidation reaction of the electrolyte solution on the surface of the positive electrode active material and can improve the battery life. However, when the amount of the adhering quantity is too small, the effect is not sufficiently manifested. If it is too high, the resistance may increase in order to inhibit the entry and exit of lithium ions.
In the present invention, the “positive electrode active material” includes a material having a composition different from the surface attached to the surface of the positive electrode active material.

(shape)
Examples of the shape of the particles of the positive electrode active material include a lump shape, a polyhedron shape, a sphere shape, an oval sphere shape, a plate shape, a needle shape, and a column shape as conventionally used. Moreover, primary particles may aggregate to form secondary particles.
(Tap density)
The tap density of the positive electrode active material is preferably 0.5 g / cm ³ or more, more preferably 0.8
g / cm ³ or more, more preferably 1.0 g / cm ³ or more. If the tap density of the positive electrode active material is lower than the lower limit, the amount of the required dispersion medium increases when the positive electrode active material layer is formed, and the necessary amount of conductive material and binder increases, so that the positive electrode to the positive electrode active material layer The filling rate of the active material is restricted, and the battery capacity may be restricted. By using a complex oxide powder having a high tap density, a high-density positive electrode active material layer can be formed. In general, the larger the tap density, the better.
There is no particular upper limit, but if it is too large, the diffusion of lithium ions using the electrolytic solution as a medium in the positive electrode active material layer becomes rate-limiting, and the load characteristics are likely to deteriorate. Therefore, the upper limit is preferably 4.0 g. / Cm ³ or less, more preferably 3.7 g / cm ³ or less, and even more preferably 3.5 g / cm ³ or less.
In the present invention, the tap density is defined as the powder packing density (tap density) g / cc when 5 to 10 g of the positive electrode active material powder is put in a 10 ml glass measuring cylinder and tapped 200 times with a stroke of about 20 mm. Ask.

(Median diameter d ₅₀ )
The median diameter d ₅₀ of the positive electrode active material particles (secondary particle diameter when primary particles are aggregated to form secondary particles) is preferably 0.3 μm or more, more preferably 0.5 μm or more, and further The upper limit is preferably 30 μm or less, more preferably 27 μm or less, still more preferably 25 μm or less, and most preferably 22 μm or less. If the lower limit is not reached, a high tap density product may not be obtained. If the upper limit is exceeded, it takes time to diffuse lithium in the particles, so that the battery performance may be lowered, or the positive electrode of the battery, that is, the active material When a conductive material, a binder, or the like is slurried with a solvent and applied as a thin film, problems such as streaking may occur. Here, different median size d ₅₀ by mixing 2 or more kinds of positive electrode active material with, it is possible to further improve the filling property at the time of the positive electrode creation.

In the present invention, the median diameter d ₅₀ is measured by a known laser diffraction / scattering particle size distribution measuring apparatus. When using LA-920 manufactured by HORIBA as a particle size distribution analyzer,
As a dispersion medium used in the measurement, a 0.1% by mass sodium hexametaphosphate aqueous solution is used, and after measuring the ultrasonic dispersion for 5 minutes, a measurement refractive index of 1.24 is set and measured.

(Average primary particle size)
When primary particles are aggregated to form secondary particles, the average primary particle diameter of the positive electrode active material is preferably 0.05 μm or more, more preferably 0.1 μm or more, and still more preferably 0.8 μm. The upper limit is preferably 5 μm or less, more preferably 4 μm or less, still more preferably 3 μm or less, and most preferably 2 μm or less. If the above upper limit is exceeded, it is difficult to form spherical secondary particles, which adversely affects the powder filling property, or the specific surface area is greatly reduced, so that there is a high possibility that battery performance such as output characteristics will deteriorate. is there. On the other hand, when the value falls below the lower limit, there is a case where problems such as inferior reversibility of charge / discharge are usually caused because crystals are not developed.

In the present invention, the primary particle diameter is measured by observation using a scanning electron microscope (SEM). Specifically, in a photograph at a magnification of 10000 times, the longest value of the intercept by the left and right boundary lines of the primary particles with respect to the horizontal straight line is obtained for any 50 primary particles and obtained by taking the average value. It is done.

(BET specific surface area)
The BET specific surface area of the positive electrode active material is preferably 0.1 m ² / g or more, more preferably 0.8 m.
2 m ² / g or more, more preferably 0.3 m ² / g or more, and the upper limit is 50 m ² / g or less, preferably 40 m ² / g or less, more preferably 30 m ² / g or less. If the BET specific surface area is smaller than this range, the battery performance tends to be lowered. If the BET specific surface area is larger, the tap density is difficult to increase, and a problem may occur in applicability when forming the positive electrode active material layer.
In the present invention, the BET specific surface area is determined by subjecting the sample to preliminary drying at 150 ° C. for 30 minutes under a nitrogen flow using a surface area meter (for example, a fully automatic surface area measuring device manufactured by Okura Riken),
It is defined by a value measured by a nitrogen adsorption BET one-point method using a gas flow method using a nitrogen-helium mixed gas accurately adjusted so that the value of the relative pressure of nitrogen with respect to atmospheric pressure is 0.3.

(Method for producing positive electrode active material)
As a manufacturing method of the positive electrode active material, a general method is used as a manufacturing method of the inorganic compound.
In particular, various methods are conceivable for preparing a spherical or elliptical active material. For example, a transition metal source material is dissolved or pulverized and dispersed in a solvent such as water, and the pH is adjusted while stirring. A spherical precursor is prepared and recovered, and dried as necessary, and then LiOH, Li ₂ CO
₃ , a method of obtaining an active material by adding a Li source such as LiNO ₃ and baking at a high temperature.

For the production of the positive electrode, the positive electrode active material may be used alone, or one or more of different compositions may be used in any combination or ratio. A preferred combination in this case is LiMn ₂ O such as LiCoO ₂ and LiNi _0.33 Co _0.33 Mn _0.33 O _2.
4 or a combination with a part of Mn substituted with another transition metal or the like, or
Combinations of those obtained by substituting a part of LiCoO ₂ or the Co in other transition metals.

<Configuration and manufacturing method of positive electrode>
The structure of the positive electrode will be described below. In the present invention, the positive electrode can be produced by forming a positive electrode active material layer containing a positive electrode active material and a binder on a current collector. Manufacture of the positive electrode using a positive electrode active material can be performed by a conventional method. That is, a positive electrode active material and a binder, and if necessary, a conductive material and a thickener mixed in a dry form into a sheet form are pressure-bonded to the positive electrode current collector, or these materials are liquid media A positive electrode can be obtained by forming a positive electrode active material layer on the current collector by applying it to a positive electrode current collector and drying it as a slurry by dissolving or dispersing in a slurry.

The content of the positive electrode active material in the positive electrode active material layer is preferably 80% by mass or more, more preferably 82% by mass or more, and particularly preferably 84% by mass or more. The upper limit is preferably 99.
It is at most mass%, more preferably at most 98 mass%. If the content of the positive electrode active material in the positive electrode active material layer is low, the electric capacity may be insufficient. Conversely, if the content is too high, the strength of the positive electrode may be insufficient.

In order to increase the packing density of the positive electrode active material, the positive electrode active material layer obtained by coating and drying
It is preferable to perform consolidation by hand press, roller press or the like. The density of the positive electrode active material layer is preferably 1.5 g / cm ³ or more as a lower limit, more preferably 2 g / cm ³ , still more preferably 2.2 g / cm ³ or more, and the upper limit is preferably 5 g / cm 3. ³ or less
More preferably, it is 4.5 g / cm < ³ > or less, More preferably, it is the range of 4 g / cm < ³ > or less. If it exceeds this range, the permeability of the electrolyte solution to the vicinity of the current collector / active material interface decreases, and the charge / discharge characteristics particularly at a high current density decrease, and a high output may not be obtained. On the other hand, if it is lower, the conductivity between the active materials is lowered, the battery resistance is increased, and high output may not be obtained.

(Conductive material)
A known conductive material can be arbitrarily used as the conductive material. Specific examples include metal materials such as copper and nickel; graphite such as natural graphite and artificial graphite (graphite); carbon black such as acetylene black; and carbon materials such as amorphous carbon such as needle coke. In addition, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio. The conductive material is usually 0.01% by mass or more, preferably 0% in the positive electrode active material layer.
. The upper limit is usually 50% by mass or less, preferably 30% by mass or less, more preferably 15% by mass or less. If the content is lower than this range, the conductivity may be insufficient. Conversely, if the content is higher than this range, the battery capacity may decrease.

(Binder)
The binder used in the production of the positive electrode active material layer is not particularly limited, and in the case of the coating method, any material that can be dissolved or dispersed in the liquid medium used during electrode production may be used. , Polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polyimide, aromatic polyamide, cellulose, nitrocellulose, and other resin polymers; SBR (styrene-butadiene rubber), NBR (acrylonitrile-butadiene rubber), fluororubber, isoprene rubber Rubber polymers such as butadiene rubber and ethylene-propylene rubber; styrene / butadiene / styrene block copolymers or hydrogenated products thereof, EP
Thermoplastic elastomeric polymers such as DM (ethylene / propylene / diene terpolymer), styrene / ethylene / butadiene / ethylene copolymer, styrene / isoprene / styrene block copolymer, or hydrogenated products thereof; Syndiotac Soft resinous polymers such as tic-1,2-polybutadiene, polyvinyl acetate, ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer; polyvinylidene fluoride (PVdF), polytetrafluoroethylene, fluorinated Fluorine polymers such as polyvinylidene fluoride and polytetrafluoroethylene / ethylene copolymers; polymer compositions having ion conductivity of alkali metal ions (particularly lithium ions), and the like. In addition, these substances may be used individually by 1 type.
You may use a seed or more together by arbitrary combinations and ratios.

The ratio of the binder in the positive electrode active material layer is usually 0.1% by mass or more, preferably 1% by mass or more,
More preferably, it is 1.5 mass% or more, and the upper limit is usually 80 mass% or less, preferably 6
It is 0 mass% or less, More preferably, it is 40 mass% or less, Most preferably, it is 10 mass% or less. When the ratio of the binder is too low, the positive electrode active material cannot be sufficiently retained and the positive electrode has insufficient mechanical strength, which may deteriorate battery performance such as cycle characteristics. On the other hand, if it is too high, battery capacity and conductivity may be reduced.

(Slurry forming solvent)
As the solvent for forming the slurry, the positive electrode active material, the conductive material, the binder, and a solvent capable of dissolving or dispersing the thickener used as necessary may be used. There is no restriction, and either an aqueous solvent or an organic solvent may be used. Examples of the aqueous medium include water, a mixed medium of alcohol and water, and the like. Examples of the organic medium include aliphatic hydrocarbons such as hexane; aromatic hydrocarbons such as benzene, toluene, xylene, and methylnaphthalene; heterocyclic compounds such as quinoline and pyridine; ketones such as acetone, methyl ethyl ketone, and cyclohexanone. Esters such as methyl acetate and methyl acrylate; amines such as diethylenetriamine and N, N-dimethylaminopropylamine; ethers such as diethyl ether, propylene oxide and tetrahydrofuran (THF); N-methylpyrrolidone (NMP) Amides such as dimethylformamide and dimethylacetamide; and aprotic polar solvents such as hexamethylphosphalamide and dimethylsulfoxide.

In particular, when an aqueous medium is used, it is preferable to make a slurry using a thickener and a latex such as styrene-butadiene rubber (SBR). A thickener is usually used to adjust the viscosity of the slurry. The thickener is not particularly limited, and specific examples include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and salts thereof. These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios. When a thickener is further added, the ratio of the thickener to the active material is 0.
1% by mass or more, preferably 0.2% by mass or more, more preferably 0.3% by mass or more,
Moreover, as an upper limit, it is 5 mass% or less, Preferably it is 3 mass% or less, More preferably, it is the range of 2 mass% or less. Below this range, applicability may be significantly reduced. Above that,
The ratio of the active material in the positive electrode active material layer may decrease, and there may be a problem that the capacity of the battery decreases and a problem that the resistance between the positive electrode active materials increases.

(Current collector)
The material of the positive electrode current collector is not particularly limited, and a known material can be arbitrarily used.
Specific examples include metal materials such as aluminum, stainless steel, nickel plating, titanium, and tantalum; and carbon materials such as carbon cloth and carbon paper. Of these, metal materials, particularly aluminum, are preferred.

Examples of the shape of the current collector include metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punch metal, and foam metal in the case of a metal material. A thin film, a carbon cylinder, etc. are mentioned. Of these, metal thin films are preferred. In addition, you may form a thin film suitably in mesh shape. The thickness of the thin film is arbitrary, but is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and the upper limit is usually 1 mm or less.
Preferably it is 100 micrometers or less, More preferably, it is 50 micrometers or less. If the thin film is thinner than this range, the strength required for the current collector may be insufficient. Conversely, if the thin film is thicker than this range, the handleability may be impaired.

Moreover, it is also preferable from the viewpoint of reducing the electronic contact resistance between the current collector and the positive electrode active material layer that a conductive additive is applied to the surface of the current collector. Examples of the conductive assistant include noble metals such as carbon, gold, platinum, and silver.
The ratio of the thickness of the current collector to the positive electrode active material layer is not particularly limited, but the value of (thickness of the positive electrode active material layer on one side immediately before electrolyte injection) / (thickness of the current collector) is 20 The lower limit is preferably 15 or less, most preferably 10 or less, and the lower limit is preferably 0.5 or more, more preferably 0.8 or more, and most preferably 1 or more. Above this range, the current collector may generate heat due to Joule heat during high current density charge / discharge. Below this range, the volume ratio of the current collector to the positive electrode active material increases and the battery capacity may decrease.

(Electrode area)
When using the non-aqueous electrolyte of the present invention, it is preferable that the area of the positive electrode active material layer is larger than the outer surface area of the battery outer case from the viewpoint of increasing the stability at high output and high temperature. Specifically, the sum of the electrode areas of the positive electrode with respect to the surface area of the exterior of the secondary battery is preferably 15 times or more, and more preferably 40 times or more. The outer surface area of the outer case is the total area obtained by calculation from the vertical, horizontal, and thickness dimensions of the case part filled with the power generation element excluding the protruding part of the terminal in the case of a bottomed square shape. . In the case of a bottomed cylindrical shape,
It is a geometric surface area that approximates a case portion filled with a power generation element excluding a protruding portion of a terminal as a cylinder. The total electrode area of the positive electrode is the geometric surface area of the positive electrode mixture layer facing the mixture layer containing the negative electrode active material, and in the structure in which the positive electrode mixture layer is formed on both sides via the current collector foil. , The sum of the areas where each surface is calculated separately.

(Thickness of positive plate)
The thickness of the positive electrode plate is not particularly limited, but from the viewpoint of high capacity and high output, the thickness of the composite layer obtained by subtracting the metal foil thickness of the core material is preferably as a lower limit with respect to one side of the current collector. Is 10 μm or more, more preferably 20 μm or more, and the upper limit is preferably 500 μm or less, more preferably 450 μm or less.

(Positive electrode surface coating)
Moreover, you may use what adhered the substance of the composition different from this to the surface of the said positive electrode plate. Surface adhering substances include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate And sulfates such as aluminum sulfate, carbonates such as lithium carbonate, calcium carbonate, and magnesium carbonate, and carbon.

5). Battery design <Electrode group>
The electrode group has a laminated structure in which the positive electrode plate and the negative electrode plate are interposed via the separator,
Any of those having a structure in which the positive electrode plate and the negative electrode plate are wound in a spiral shape with the separator interposed therebetween may be used. The ratio of the volume of the electrode group to the internal volume of the battery (hereinafter referred to as electrode group occupancy) is usually 40% or more, preferably 50% or more, and usually 90% or less.
80% or less is preferable.

When the electrode group occupancy is below the above range, the battery capacity decreases. Also, if the above range is exceeded, the void space is small, the battery expands, and the member expands or the vapor pressure of the electrolyte liquid component increases and the internal pressure rises. In some cases, the gas release valve that lowers various characteristics such as storage at high temperature and the like, or releases the internal pressure to the outside is activated.

<Current collection structure>
The current collecting structure is not particularly limited, but in order to more effectively realize the high current density charge / discharge characteristics by the non-aqueous electrolyte solution of the present invention, a structure that reduces the resistance of the wiring part and the joint part is used. It is preferable. Thus, when internal resistance is reduced, the effect of using the non-aqueous electrolyte solution of this invention is exhibited especially favorable.

In the case where the electrode group has the above laminated structure, a structure formed by bundling the metal core portions of the electrode layers and welding them to the terminals is preferably used. When the area of one electrode increases, the internal resistance increases. Therefore, it is also preferable to provide a plurality of terminals in the electrode to reduce the resistance. When the electrode group has the winding structure described above, the internal resistance can be lowered by providing a plurality of lead structures for the positive electrode and the negative electrode, respectively, and bundling the terminals.

<Exterior case>
The material of the outer case is not particularly limited as long as it is a substance that is stable with respect to the non-aqueous electrolyte used. Specifically, a nickel-plated steel plate, stainless steel, aluminum, an aluminum alloy, a metal such as a magnesium alloy, or a laminated film (laminate film) of a resin and an aluminum foil is used. From the viewpoint of weight reduction, an aluminum or aluminum alloy metal or a laminate film is preferably used.

In an exterior case using metals, the metal is welded together by laser welding, resistance welding, or ultrasonic welding to form a sealed sealed structure, or a caulking structure using the above metals via a resin gasket. Things. Examples of the outer case using the laminate film include a case where a resin-sealed structure is formed by heat-sealing resin layers. In order to improve sealing performance, a resin different from the resin used for the laminate film may be interposed between the resin layers. In particular, when a resin layer is heat-sealed through a current collecting terminal to form a sealed structure, a metal and a resin are joined, so that a resin having a polar group or a modified group having a polar group introduced as an intervening resin is used. Resins are preferably used.

<Protective element>
As a protection element, PTC (PositiveTe) that increases resistance when abnormal heat generation or excessive current flows
mperature Coefficient), temperature fuse, thermistor, and a valve (current cutoff valve) that shuts off the current flowing in the circuit due to a sudden rise in the internal pressure or internal temperature of the battery when abnormal heat is generated. It is preferable to select a protective element that does not operate under normal use at a high current, and it is more preferable that the protective element is designed so as not to cause abnormal heat generation or thermal runaway even without the protective element.

<Exterior body>
The non-aqueous electrolyte secondary battery of the present invention is usually configured by housing the non-aqueous electrolyte, the negative electrode, the positive electrode, the separator, and the like in an exterior body. This exterior body is not particularly limited, and any known one can be arbitrarily adopted as long as the effects of the present invention are not significantly impaired. Specifically, the material of the exterior body is arbitrary, but usually, for example, nickel-plated iron, stainless steel, aluminum or an alloy thereof, nickel, titanium, or the like is used.
The shape of the exterior body is also arbitrary, and may be any of a cylindrical shape, a square shape, a laminate shape, a coin shape, a large size, and the like.

6). Battery Performance The non-aqueous electrolyte secondary battery of the present invention can be used without particular limitation, but can be preferably used for a battery having a high voltage or a high capacity.
For example, in the case of a lithium ion secondary battery, the increase in voltage is usually 4.25 V or more, preferably 4.3 or more.
The increase in capacity is usually 2600 mAh or more, preferably 2800 mAh or more, more preferably 3000 mAh or more in the case of an 18650 type battery, for example.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.
[Example A]
[Production of negative electrode]
98 parts by mass of a carbonaceous material, 100 parts by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of 1% by mass of sodium carboxymethylcellulose) and an aqueous dispersion of styrene-butadiene rubber (as a thickener and a binder, respectively)
1 part by mass of styrene-butadiene rubber (concentration: 50% by mass) was added and mixed with a disperser to form a slurry. The obtained slurry was applied to a copper foil having a thickness of 10 μm, dried, and rolled with a press, and the size of the active material layer was 30 mm wide, 40 mm long, and 5 mm wide,
It cut out into the shape which has an uncoated part of length 9mm, and it was set as the negative electrode used for Example 1 and Comparative Examples 1-3, respectively.

[Production of positive electrode]
90% by mass of Li _1.1 Ni _0.45 Mn _0.45 Co _0.1 O ₂ as a positive electrode active material, 5% by mass of acetylene black as a conductive material, and polyvinylidene fluoride (PVdF) 5 as a binder
% By mass was mixed in N-methylpyrrolidone solvent to make a slurry. The obtained slurry was applied to an aluminum foil having a thickness of 15 μm, dried, and rolled with a press. The active material layer was 30 mm in width, 40 mm in length, 5 mm in width, and 9 mm in length. It cut out into the shape which has a process part, and it was set as the positive electrode used for Example 1 and Comparative Examples 1-3, respectively.

[Manufacture of electrolyte 1]
Under a dry argon atmosphere, ethylene carbonate (EC) and dimethyl carbonate (DM
A basic electrolyte solution was prepared by dissolving LiPF ₆ dried in a mixture of C) and ethyl methyl carbonate (EMC) (volume ratio 30:30:40) at a ratio of 1 mol / L. The basic electrolyte solution was mixed with the compounds shown in Table 1 to obtain electrolyte solutions used in Examples 1 to 11 and Comparative Examples 1 to 8, respectively.

[Manufacture of lithium secondary batteries]
The positive electrode, the negative electrode, and a separator containing the amount of calcium element described in Table 1 were stacked in the order of the negative electrode, the separator, and the positive electrode to prepare a battery element. In addition, this separator was produced so that it might become a three-layer structure of polypropylene-polyethylene-polypropylene, and thickness was 25 micrometers. The content of aluminum element in the separator used was 45 ppm. The battery element was inserted into a bag made of a laminate film in which both surfaces of aluminum (thickness: 40 μm) were coated with a resin layer while projecting positive and negative terminals, and each of the electrolyte solutions shown in Table 1 was placed in the bag. And a vacuum-sealing was performed to produce a sheet-like battery, which was used for Examples 1 to 11 and Comparative Examples 1 to 8, respectively.

[Run-in operation]
In a state where the lithium secondary battery is sandwiched between glass plates in order to improve the adhesion between the electrodes,
The running-in operation was performed at a constant current corresponding to 0.2C. Here, 1C represents a current value that discharges the reference capacity of the battery in one hour, 2C represents a current value that is twice that, and 0.2C represents a current value that is 1/5 of the current value.

[Evaluation of cycle characteristics]
The battery that had been subjected to the running-in operation was charged at a constant current of 2C at 60 ° C. and then discharged at a constant current of 2C, and 300 cycles were performed. The discharge capacity retention ratio was calculated from the formula of (discharge capacity at 300th cycle) ÷ (discharge capacity at the first cycle) × 100. The evaluation results are shown in Table 1.

[Example B]
[Production of negative electrode]
98 parts by mass of a carbonaceous material, 100 parts by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of 1% by mass of sodium carboxymethylcellulose) and an aqueous dispersion of styrene-butadiene rubber (as a thickener and a binder, respectively)
1 part by mass of styrene-butadiene rubber (concentration: 50% by mass) was added and mixed with a disperser to form a slurry. The obtained slurry was applied to a copper foil having a thickness of 10 μm, dried, and rolled with a press, and the size of the active material layer was 30 mm wide, 40 mm long, and 5 mm wide,
Cut into a shape having an uncoated part with a length of 9 mm, Examples 12 to 17 and Comparative Example 9 respectively.
10 was used as the negative electrode.

[Production of positive electrode]
85% by mass of LiNi _0.33 Mn _0.33 Co _0.33 O ₂ as a positive electrode active material, 10% by mass of acetylene black as a conductive material, and polyvinylidene fluoride (PVdF) 5 as a binder
% By mass was mixed in N-methylpyrrolidone solvent to make a slurry. The obtained slurry was applied to an aluminum foil having a thickness of 15 μm, dried, and rolled with a press. The active material layer was 30 mm in width, 40 mm in length, 5 mm in width, and 9 mm in length. It cut out into the shape which has a process part, and it was set as the positive electrode used for Examples 12-17 and Comparative Examples 9 and 10, respectively.

[Manufacture of electrolyte 2]
Under a dry argon atmosphere, ethylene carbonate (EC) and dimethyl carbonate (DM
A basic electrolyte solution was prepared by dissolving LiPF ₆ dried in a mixture of C) and ethyl methyl carbonate (EMC) (volume ratio 30:30:40) at a ratio of 1 mol / L. The basic electrolyte solution was mixed with the compounds shown in Table 2 to obtain electrolyte solutions used in Examples 12 to 15 and Comparative Examples 9 and 10, respectively.

[Manufacture of electrolyte 3]
Under a dry argon atmosphere, fluoroethylene carbonate (FEC) and sulfolane (SL
F), LiPF ₆ dried in a mixture (volume ratio 10: 20: 30: 40) of dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC) so as to have a ratio of 1 mol / L is dissolved in the basic electrolyte. Was prepared. The basic electrolyte solution was mixed with the compounds shown in Table 2 to obtain electrolyte solutions used in Examples 16 and 17, respectively.

[Manufacture of lithium secondary batteries]
The positive electrode, the negative electrode, and a separator containing the amount of calcium element described in Table 1 were stacked in the order of the negative electrode, the separator, and the positive electrode to prepare a battery element. In addition, this separator was produced so that it might become a three-layer structure of polypropylene-polyethylene-polypropylene, and thickness was 25 micrometers. The content of aluminum element in the separator used was 45 ppm. The battery element was inserted into a bag made of a laminate film in which both surfaces of aluminum (thickness: 40 μm) were covered with a resin layer while projecting positive and negative terminals, and each electrolyte solution shown in Table 2 was then placed in the bag. And a vacuum-sealing was performed to produce a sheet-like battery, which was used for Examples 12 to 17 and Comparative Examples 9 and 10, respectively.

[Run-in operation]
In a state where the lithium secondary battery is sandwiched between glass plates in order to improve the adhesion between the electrodes,
The running-in operation was performed at a constant current corresponding to 0.2C. Here, 1C represents a current value that discharges the reference capacity of the battery in one hour, 2C represents a current value that is twice that, and 0.2C represents a current value that is 1/5 of the current value.

[Evaluation of cycle characteristics]
The battery that had been subjected to the running-in operation was charged at a constant current of 2C at 60 ° C. and then discharged at a constant current of 2C, and 300 cycles were performed. 0 every 100 cycles
. The capacity was confirmed at 2C. The discharge capacity retention rate was determined from the formula of (discharge capacity at 300th cycle (0.2 C)) / (discharge capacity at first cycle (0.2 C)) × 100. The evaluation results are shown in Table 2.

As is clear from Tables 1 and 2, in the battery using the electrolytic solution in which the compound containing the carbon-carbon triple bond is introduced, compared to the case where the compound not containing the carbon-carbon triple bond is not introduced. Excellent discharge capacity retention rate. In the compound containing a carbon-carbon triple bond, a protective coating derived from polymerization or the like by a compound containing a carbon-carbon triple bond is highly developed on the surface of the electrode, and the side decomposition reaction caused by electrolyte components other than the above is suppressed. It is estimated that the durability characteristic of the battery is improved by the mechanism.

Here, when attention is paid to the relationship between the Ca concentration and the discharge capacity retention rate, in a battery using an electrolytic solution into which a compound containing a carbon-carbon triple bond is introduced, the discharge capacity retention rate tends to decrease as the Ca concentration increases. It is in. When the separator contains more than a certain amount of Ca, C in the separator
a, a counter anion of Ca, a compound containing Ca, etc.
It is presumed that the electrode protection effect of the compound containing a carbon triple bond does not function effectively. Thus, in order to improve the discharge capacity maintenance rate of the battery, it is preferable that a compound containing a carbon-carbon triple bond is introduced, but when a large amount of Ca or the like is mixed, the carbon-carbon triple bond is introduced. The durability improvement effect of the compound containing a bond tends to be easily impaired.

On the other hand, even in the case of a compound having a structure similar to that of the example, when a compound containing a carbon-carbon double bond instead of a carbon-carbon triple bond is introduced, or without these compounds being added, the electrolyte And a solvent only (Comparative Examples 1 and 2), a stable coating is not formed on the electrode surface, and the discharge capacity retention rate is at a very low level.
It is assumed that even if the concentration changes, it is not reflected in the discharge capacity maintenance rate.

From the above results, in order to improve the discharge capacity retention rate in the advanced durability test, it is necessary not only to simply introduce a compound containing a carbon-carbon triple bond, but also to sufficiently reduce the impurity concentration in the separator. It shows that there is.

The non-aqueous electrolyte solution of the present invention is extremely useful because the durability characteristics of the non-aqueous electrolyte secondary battery can be improved to a high degree. Therefore, the non-aqueous electrolyte solution of the present invention and the non-aqueous electrolyte secondary battery using the same can be used for various known applications. As a specific example, for example,
Notebook PC, pen input PC, mobile PC, electronic book player, mobile phone, mobile fax, mobile copy, mobile printer, headphone stereo, video movie, LCD TV, handy cleaner, portable CD, mini-disc, transceiver, electronic notebook, calculator , Memory cards, portable tape recorders, radios, backup power supplies, motors, automobiles, motorcycles, motorbikes, bicycles, lighting equipment, toys, game equipment, watches, power tools, strobes, cameras, load leveling power supplies, natural energy Examples include a storage power source.

Claims (3)

Nonaqueous electrolyte solution comprising a nonaqueous electrolyte solution containing an electrolyte and a nonaqueous solvent that dissolves the electrolyte, a negative electrode capable of occluding and releasing lithium ions, a positive electrode, and a separator having a polyolefin resin as a component. An electrolyte secondary battery,
The non-aqueous electrolyte contains a compound having a carbon-carbon triple bond represented by the following general formula (1) and / or (2),
And the compounding quantity of the compound which has this carbon-carbon triple bond is 0.01 mass% or more and 5 mass% or less in 100 mass% of this non-aqueous electrolyte solution,
The separator contains calcium element, and the concentration of the calcium element contained in the separator is 100 ppm or less;
The non-aqueous electrolyte secondary battery, wherein the separator contains an aluminum element, and the concentration of the aluminum element contained in the separator is 150 ppm or less.

(In the formula _{(1) ~ (2),} R 1 ~R 9 are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, 3 to 6 carbon atoms a cycloalkyl group or having 6 to 12 carbon atoms Represents an aryl group, R
₂ and R ₃ , R ₅ and R ₆ , R ₇ and R ₈ may be bonded to each other to form a cycloalkyl group having 3 to 6 carbon atoms. x and y represent an integer of 1 or 2. Y ₁ and Y ₂ are represented by the formula (3)
It may be the same or different.

Z ₁ is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms,
An aryl group having 6 to 12 carbon atoms or an aralkyl group having 7 to 12 carbon atoms is shown. ) The nonaqueous electrolyte secondary battery according to claim 1, wherein a concentration of calcium element contained in the separator is 30 ppm or less. The non-aqueous electrolyte according to claim 1 or 2, wherein the compound having a carbon-carbon triple bond is a compound having a carbonate ester skeleton, a sulfonate ester skeleton, a sulfate ester skeleton, or a sulfite ester skeleton. Secondary battery.