JP3410027B2 - Non-aqueous electrolyte battery - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte battery. 2. Description of the Related Art In recent years, electronic devices such as portable radio telephones, portable personal computers, and portable video cameras have been developed, and various electronic devices have been miniaturized so as to be portable. Along with this, a battery having a high energy density and a light weight is also adopted as a built-in battery. A typical battery that satisfies such requirements is an active material such as lithium metal or lithium alloy, and a lithium ion as a host material (here, the host material refers to a material that can occlude and release lithium ions). LiClO ₄ , LiPF ₆
This is a lithium secondary battery using an aprotic organic solvent in which a lithium salt such as the above is dissolved as an electrolyte. A lithium secondary battery has a negative electrode plate in which the above-mentioned negative electrode material is held on a negative electrode current collector as a support, and a reversible electrochemical reaction with lithium ions, such as a lithium nickel composite oxide. A positive electrode plate holding the positive electrode active material to be supported on a positive electrode current collector as a support, and a separator that holds an electrolyte and intervenes between the negative electrode plate and the positive electrode plate to prevent a short circuit between the two electrodes. I have. In the case of a strip-shaped or cylindrical battery, the positive electrode plate, the separator, and the negative electrode plate are each formed by sequentially laminating thin sheets or foils, or spirally winding and then wrapped in a battery container. Is stored in. In addition, as the current collector of the electrode plate,
Since it is necessary to have its own conductivity, a metal foil such as copper or aluminum has been used. [0004] Further, in the case of a device using a battery as a power source, not limited to a lithium-based secondary battery, the demand for weight reduction and safety of the whole device is not exhausted. In addition, users who prefer battery performance that is higher than existing products, lighter, and safer. In order to achieve the object, a non-aqueous electrolyte secondary battery characterized by using an electrically insulating thin film such as a resin for a battery container has already been proposed (Japanese Patent Application No. 10-1).
00038). [0005] In this proposed battery, a metal laminated resin sheet is used in a battery case (hereinafter, referred to as a battery case).
Used as a laminate case). Then, the metal laminated resin sheet is heat-sealed to seal the battery.
Compared to a conventionally used metal rigid case, the laminate case is weak against external force and easily deformed. Therefore, especially when left at high temperatures, the electrolyte is vaporized, or the electrochemical or thermal decomposition of the electrolyte by oxidation or reduction on the surface of the positive electrode / negative electrode active material,
An excessive gas is generated in the battery, and the battery using the laminate case expands and deforms due to an increase in the battery internal pressure. On the other hand, in a lithium-based battery, since a high voltage can be obtained, it is desirable to select an electrolyte having excellent withstand voltage characteristics. Propylene carbonate is a candidate, and a carbon material is used for a negative electrode. In this case, propylene carbonate is decomposed. Therefore, propylene carbonate was not suitable for use as an electrolyte for a non-aqueous electrolyte battery using a carbon material as a negative electrode, even though it has advantages as an electrolyte. Accordingly, the present invention has been made in view of the above problems, and has as its object to provide a non-aqueous electrolyte battery excellent in high temperature resistance, withstand voltage characteristics and the like. [0008] A non-aqueous electrolyte battery according to the first invention is a wound flat plate having a positive electrode, a separator and a negative electrode made of a carbon material in a battery container made of a metal laminated resin sheet. A power generating element, comprising an electrolytic solution, wherein the solvent of the electrolytic solution is a mixed solvent of vinylene carbonate, propylene carbonate, and a chain carbonate ;
The composition of the above vinylene carbonate with respect to all the solvents is expressed as A volume.
% Relative to the total solvent of the propylene carbonate.
Assuming that the composition is B volume%, 10 ≦ (A + B) ≦ 50 (
However, and wherein this <br/> and is A ≠ 0 and B ≠ 0) and 3 ≦ A ≦ 20. In the battery according to the present invention, the weight of the battery can be reduced by providing a conductive thin film on both or one side of the electrically insulating thin film as a current collector. Is possible. As the salt contained in the electrolytic solution, LiPF ₆ used in the electrolytic solution of the conventional non-aqueous electrolyte battery may be used, but the lithium imide salt does not cause a thermal decomposition reaction up to around 300 ° C. , LiPF ₆ is much more excellent in thermal stability as compared with pyrolysis at around 45 ° C., so that LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiCF ₃ C
When used in a mixture with at least one salt selected from the group consisting of O ₂ and LiCF ₃ SO ₃ , it is possible to effectively reduce the amount of gas generated when the battery is left at a high temperature. A greater effect can be obtained by combining with the solvent in the above. An embodiment of the present invention will be described based on an embodiment. The solvent in the electrolytic solution was propylene carbonate, which was 10, 20, 30, and 40 of the total solvent.
Vol% was used as a base, and each having a composition in which the volume ratio of vinylene carbonate to diethyl carbonate was changed. First, the case where propylene carbonate is 10 vol% in the solvent composition in the electrolytic solution will be described. Embodiment 1 FIG. 2 shows a cross-sectional structure of a nonaqueous electrolyte secondary battery according to Embodiment 1 of the present invention. In FIG. 2, reference numeral 100 denotes a non-aqueous electrolyte secondary battery. A battery power generating element 30 formed by winding a tape-shaped electrode plate in a flat shape is impregnated with an electrolytic solution, and then hermetically sealed into a battery container 9 made of an aluminum laminated sheet. Has become. FIG. 1 shows a cross section of an electrode plate constituting a battery power generating element 30. In FIG. 1, reference numeral 1 denotes a positive electrode mixture layer, 2 denotes a positive electrode current collector layer, and 3 denotes an insulating material. The insulator layer 4, the negative electrode current collector layer 5, the negative electrode mixture layer 6, and the separator 6 are separators, and these are sequentially laminated to form the electrode plate 20.
The separator 6 is a polyethylene microporous membrane here. The positive electrode mixture layer 1 comprises 6 parts by weight of polyvinylidene fluoride as a binder, 3 parts by weight of acetylene black as a conductive agent, and LiCo _0.15 Ni _0.82 Al _{0.03 as} an active material.
An active material paste obtained by appropriately adding N-methylpyrrolidone as a solvent to 91 parts by weight of O ₂ and mixing the resultant was coated on the positive electrode current collector layer 2 so that the coating weight after drying was 2.44 g / 100 cm ^2. It was dried and pressed to a thickness of 70 μm. However, the positive electrode mixture layer 2 was not applied to the lead attachment portion. The positive electrode current collector layer 2 is formed by depositing aluminum foil having a thickness of 2 μm on both surfaces of the insulator layer 3. As the insulator layer 3, a polyethylene terephthalate resin film having a thickness of 10 μm was used. The negative electrode mixture layer 5 has a coating weight of 1.20 g / 100 cm ^{2 of} a negative electrode paste obtained by appropriately mixing N-methylpyrrolidone with a mixture of 92 parts by weight of graphite and 8 parts by weight of polyvinylidene fluoride. It was applied to the negative electrode current collector layer 4, dried, and pressed to a thickness of 80 μm. The negative electrode current collector layer 4 was made of copper having a thickness of 3 μm, and was formed by first depositing nickel and then electroplating copper having a thickness of 3 μm. However, the negative electrode mixture layer 5 was not applied to the lead attachment portion. Next, a terminal lead (not shown) was attached to each of the positive and negative electrodes to the current collector of the electrode plate. Next, a laminate of the electrode plate and the separator 6 was wound to produce a flat electrode body. Next, a positive electrode terminal and a negative electrode terminal are taken out from the positive electrode current collector layer 2 and the negative electrode current collector layer 4, respectively.
As shown in FIG. 2, LiPF ₆ was placed in an aluminum laminate case 9 and mixed with propylene carbonate (PC), vinylene carbonate (VC) and diethyl carbonate (DEC) at a volume ratio of 10: 3: 87, and LiPF ₆ was mixed with 1M.
After impregnating 2.5 g of the dissolved electrolyte in a vacuum, the aluminum laminate case 9 was sealed by heat sealing to obtain a design capacity of 60.
100 batteries according to the present invention with 0 mAh were produced. Here, the aluminum laminate case 9 for the hermetically sealed port has a 12 μm PET as a surface protective layer on the outermost layer.
A 15 μm aluminum foil as a barrier layer under the film, and a 50 μm
It consists of a laminated sheet having m acid-modified LDPE (low density polyethylene). The lead terminal is made of a 50-100 μm acid-modified LDP as an adhesive layer with a metal conductor such as copper, aluminum, nickel or the like of 50-100 μm.
One provided with an E layer is exemplified. Here, aluminum is used for the positive electrode lead terminal and copper is used for the negative electrode lead terminal. However, the configuration of the aluminum laminate case 9 and the leads, the lead extraction from the aluminum laminate case 9, and the like may be achieved by a known method. Embodiment 2 In the battery manufacturing method shown in Embodiment 1,
The electrolyte solvent is propylene carbonate (PC), vinylene carbonate (VC) and diethyl carbonate (DE
100 similar batteries were produced except that the volume ratio of C) was changed to 10: 5: 85. Embodiment 3 In the battery manufacturing method shown in Embodiment 1,
The electrolyte solvent is propylene carbonate (PC), vinylene carbonate (VC) and diethyl carbonate (DE
100 similar batteries were produced except that the volume ratio of C) was changed to 10:10:60. Embodiment 4 In the battery manufacturing method shown in Embodiment 1,
The electrolyte solvent is propylene carbonate (PC), vinylene carbonate (VC) and diethyl carbonate (DE
100 similar batteries were produced except that the volume ratio of C) was changed to 10:20:70. Comparative Example 1 In the battery manufacturing method shown in Example 1, the electrolyte solvent was propylene carbonate (P
C), and 100 similar batteries were produced except that the volume ratio of vinylene carbonate (VC) and diethyl carbonate (DEC) was 10: 1: 89. Comparative Example 2 In the battery manufacturing method shown in Example 1, the electrolyte solvent was propylene carbonate (P
C), 100 similar batteries were produced except that the volume ratio of vinylene carbonate (VC) to diethyl carbonate (DEC) was 10:40:50. Comparative Example 3 In the battery manufacturing method shown in Example 1, the electrolyte solvent was propylene carbonate (P
C), 100 similar batteries were produced except that the volume ratio of vinylene carbonate (VC) to diethyl carbonate (DEC) was 10:50:40. Comparative Example 4 In the battery manufacturing method shown in Example 1, the electrolyte solvent was propylene carbonate (P
C), 100 similar batteries were produced except that the volume ratio of vinylene carbonate (VC) to diethyl carbonate (DEC) was 10:60:30. Next, the case where the solvent composition in the electrolytic solution is 20 vol% of propylene carbonate will be described. Embodiment 5 In the battery manufacturing method shown in Embodiment 1,
The electrolyte solvent is propylene carbonate (PC), vinylene carbonate (VC) and diethyl carbonate (DE
100 similar batteries were produced except that the volume ratio of C) was changed to 20: 3: 77. Embodiment 6 In the battery manufacturing method shown in Embodiment 1,
The electrolyte solvent is propylene carbonate (PC), vinylene carbonate (VC) and diethyl carbonate (DE
100 similar batteries were manufactured except that the volume ratio of C) was changed to 20: 5: 75. Embodiment 7 In the battery manufacturing method shown in Embodiment 1,
The electrolyte solvent is propylene carbonate (PC), vinylene carbonate (VC) and diethyl carbonate (DE
100 similar batteries were produced except that the volume ratio of C) was changed to 20:10:70. Embodiment 8 In the battery manufacturing method shown in Embodiment 1,
The electrolyte solvent is propylene carbonate (PC), vinylene carbonate (VC) and diethyl carbonate (DE
100 similar batteries were produced except that the volume ratio of C) was changed to 20:20:60. Comparative Example 5 In the battery manufacturing method shown in Example 1, the electrolyte solvent was propylene carbonate (P
C), and 100 similar batteries were produced except that the volume ratio of vinylene carbonate (VC) and diethyl carbonate (DEC) was 20: 1: 79. Comparative Example 6 In the battery manufacturing method shown in Example 1, the electrolyte solvent was propylene carbonate (P
C), 100 similar batteries were produced except that the volume ratio of vinylene carbonate (VC) to diethyl carbonate (DEC) was 20:30:50. Comparative Example 6 In the battery manufacturing method shown in Example 1, the electrolyte solvent was propylene carbonate (P
C), 100 similar batteries were produced except that the volume ratio of vinylene carbonate (VC) to diethyl carbonate (DEC) was 20:40:40. Next, the case where propylene carbonate is 30 vol% in the solvent composition in the electrolytic solution will be described. Embodiment 9 In the battery manufacturing method shown in Embodiment 1,
The electrolyte solvent is propylene carbonate (PC), vinylene carbonate (VC) and diethyl carbonate (DE
100 similar batteries were produced except that C) was changed to a volume ratio of 30: 3: 67. Example 10 In the battery manufacturing method shown in Example 1, the electrolyte solvent was propylene carbonate (PC), vinylene carbonate (VC) and diethyl carbonate (DEC) in a volume ratio of 30: 5: 65. Except for the above, 100 similar batteries were manufactured. EXAMPLE 11 In the battery manufacturing method shown in Example 1, the electrolyte solvent was propylene carbonate (PC), vinylene carbonate (VC) and diethyl carbonate (DEC) in a volume ratio of 30:10:60. Except for the above, 100 similar batteries were manufactured. Example 12 In the battery manufacturing method shown in Example 1, the electrolyte solvent was propylene carbonate (PC), vinylene carbonate (VC) and diethyl carbonate (DEC) in a volume ratio of 30:20:50. Except for the above, 100 similar batteries were manufactured. Comparative Example 8 In the battery manufacturing method shown in Example 1, the electrolyte solvent was propylene carbonate (P
C), 100 similar batteries were produced except that the volume ratio of vinylene carbonate (VC) to diethyl carbonate (DEC) was 30: 1: 69. Comparative Example 9 In the battery manufacturing method shown in Example 1, the electrolyte solvent was propylene carbonate (P
C), except that the volume ratio of vinylene carbonate (VC) and diethyl carbonate (DEC) was 30:30:40, 100 similar batteries were manufactured. Comparative Example 10 In the battery manufacturing method shown in Example 1, the electrolyte solvent was propylene carbonate (PC), vinylene carbonate (VC) and diethyl carbonate (DEC) in a volume ratio of 30:40:30. Except for the above, 100 similar batteries were manufactured. Next, the case where the solvent composition in the electrolytic solution is 40 vol% of propylene carbonate will be described. Example 13 In the battery manufacturing method shown in Example 1, the electrolyte solvent was propylene carbonate (PC), vinylene carbonate (VC) and diethyl carbonate (DEC) in a volume ratio of 40: 3: 57. Except for the above, 100 similar batteries were manufactured. EXAMPLE 14 In the battery manufacturing method shown in Example 1, the electrolyte solvent was propylene carbonate (PC), vinylene carbonate (VC) and diethyl carbonate (DEC) in a volume ratio of 40: 5: 55. Except for the above, 100 similar batteries were manufactured. Embodiment 15 In the battery manufacturing method shown in Embodiment 1, the electrolyte solvent was propylene carbonate (PC), vinylene carbonate (VC) and diethyl carbonate (DEC) in a volume ratio of 40:10:50. Except for the above, 100 similar batteries were manufactured. Comparative Example 11 In the battery manufacturing method shown in Example 1, the electrolyte solvent was propylene carbonate (PC), vinylene carbonate (VC) and diethyl carbonate (DEC) at a volume ratio of 40: 1: 59. Except for the above, 100 similar batteries were manufactured. [Comparative Example 12] In the battery manufacturing method shown in Example 1, the electrolyte solvent was propylene carbonate (PC), vinylene carbonate (VC) and diethyl carbonate (DEC) in a volume ratio of 40:20:40. Except for the above, 100 similar batteries were manufactured. The batteries according to the present invention obtained in Examples 1 to 15 and the batteries of Comparative Examples 1 to 12 were allowed to stand for several hours.
The battery was charged at a constant current and a constant voltage up to 4.2 V with a current of 5 C for 3 hours to obtain a fully charged state. Then at 85 ° C for 30
Left at high temperature for days. At this time, Tables 1 to 4 show the measurement results of the number of batteries whose laminated case was opened due to the gas pressure generated by the gas generated in the batteries and the battery capacity after high temperature storage. In addition, the numerical value of the capacity retention rate in Tables 1-4 is an average value of the battery which did not open after standing. [Table 1] [Table 2] [Table 3] [Table 4] A battery similar to that of Example 1 was manufactured, and the battery using only PC as the electrolyte could not be charged / discharged for the first time, but the battery containing 1 vol% of VC in the electrolyte had an electrolyte containing PC. Charge / discharge was possible even with a liquid. From these tables, it can be seen that, at 85 ° C. in the charged state, 3
The sum of the cyclic carbonates of PC and VC was 10 to 50 v for the number of openings of the laminate case during leaving for 0 days.
In the case where an electrolytic solution containing 3% to 20% by volume of VC and a VC content of 3% to 20% by volume was used, the case numerical aperture of the battery was 0.
The amount of increase in the battery thickness of the battery of the present example after being left was very small as compared with that of the battery of the comparative example. Then, when these batteries were disassembled and the gas volume in the batteries was investigated, it was found that the gas amount of the example of the present invention was smaller than the gas volume in the battery of the comparative example. That is, although the detailed reaction mechanism has not been elucidated, the amount of gas generated in the battery is small even when the battery is left at a high temperature. Is considered to be resistant to redox decomposition and thermal decomposition. In particular, in a battery using a laminate case, when used in a high temperature state, the amount of increase in thickness can be greatly reduced, and the rate of occurrence of openings in the laminate case can be significantly reduced. In addition, it is possible to prevent the battery contents from leaking when the laminate case is opened. In addition, from Tables 1 to 4, it was clarified that the battery of the example of the present invention had a higher capacity retention ratio than the battery of the comparative example after being left at a high temperature. In the examples, LiPF ₆ was used as the lithium salt dissolved in the electrolytic solution. However, the lithium salt is not limited to this, and LiBF ₄ ,
LiAsF ₆ , LiCF ₃ CO ₂ , LiCF ₃ SO ₃ , Li
N (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ CF ₂ CF ₃ ) ₂ , L
iN (COCF ₃ ) ₂ and LiN (COCF ₂ CF ₃ ) ₂
Or a mixture thereof. In Examples, propylene carbonate and vinylene carbonate were used as the cyclic carbonate as the solvent for the electrolytic solution, and diethyl carbonate was used as the chain carbonate, and a mixed solution of these was used. However, the chain carbonate is not limited to this, and dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate or a mixture thereof may be used. Further, although the separator is used in this embodiment as the separator used in the battery according to the present invention, a lithium ion conductive polymer solid electrolyte membrane can be used or used in combination as the separator. In this case, if the electrolytic solution contained in the lithium ion conductive polymer solid electrolyte is the solvent composition of the electrolytic solution in the present invention, the same effects as those of the batteries described in the examples can be obtained. In addition, the solid electrolyte membrane used or used in combination as the separator is not limited to the above organic material, but may be any of an inorganic material and a mixture thereof. When the solid electrolyte membrane is an organic solid material such as polyethylene oxide, polyacrylonitrile, polyethylene glycol and a modified product thereof, the solid electrolyte membrane is lighter and more flexible than the inorganic solid material, and is less likely to crack during winding because it is flexible. . On the other hand, when the solid electrolyte is a lithium ion conductive inorganic solid material such as lithium lanthanum perovskite, the solid electrolyte has heat resistance and thus has excellent reliability at high temperatures. In addition, when the electrolyte membrane is a mixture of an organic material and an inorganic material, both can compensate for the other disadvantage while providing both advantages. That is, even if the organic substance in the mixture is dissolved, the organic substance is retained by the inorganic substance and thus does not flow away. Even if the amount of the inorganic substance is large, the organic substance functions as a binder and does not break. When the electrolyte membrane is a mixture, if one component is an electrolyte, the other component is an inorganic material (inorganic filler) such as magnesium oxide, silicon oxide, or a calcium salt of silicon oxide, or a mixture of these inorganic materials. An electrolyte may be used. The composition may be, for example, 70 to 85% of an inorganic substance, 10 to 15% of an organic solid material, and others (such as a binder). Further, in the above embodiment, LiCo as a compound capable of inserting and extracting lithium as a positive electrode material was used as LiCo.
_{Although 0.15} Ni _0.82 Al _0.03 O ₂ is used, the cathode material is not limited to this. In addition, as the inorganic compound, a composition formula Li _x MO ₂ or Li _y M ₂ O
₄ (where M is a transition metal, 0 ≦ x ≦ 1, 0 ≦ y ≦ 2)
Embedded image, oxides having tunnel-like vacancies, and metal chalcogenides having a layered structure can be used. Specific examples thereof include LiCoO ₂ , LiNiO
₂ , LiMn ₂ O ₄ , Li ₂ Mn ₂ O ₄ , MnO ₂ , Fe
O ₂ , V ₂ O ₅ , V ₆ O ₁₃ , TiO ₂ , TiS _{2 and the} like can be mentioned. Examples of the organic compound include a conductive polymer such as polyaniline. Further, the above-mentioned various active materials may be mixed and used irrespective of an inorganic compound or an organic compound. Further, in the above embodiment, graphite is used as a material for storing and releasing lithium as a negative electrode material. However, the negative electrode material is not limited to this, and is a carbon material capable of storing and releasing lithium. If it exists, it can be used as a negative electrode material. According to the nonaqueous electrolyte battery according to the present invention,
Even when the battery is left at a high temperature, decomposition of the electrolytic solution and generation of steam inside the battery are extremely effectively suppressed. As a result, the battery thickness does not significantly increase and the battery internal pressure does not increase. Moreover, since propylene carbonate having excellent withstand voltage characteristics, cycle characteristics, and low-temperature characteristics can be used as a main solvent in the electrolyte, a nonaqueous electrolyte battery having excellent battery characteristics can be provided. Furthermore, it is possible to provide a non-aqueous electrolyte battery which is capable of preventing the opening of a battery container having a component of metal and resin, for example, a laminate case, and which is excellent in volume energy density and extremely lightweight. Can be. In addition, it is possible to provide a non-aqueous electrolyte battery that has a small decrease in charge / discharge performance before and after the history even if the battery has experienced a high-temperature history. As described above, the battery according to the present invention is safe and excellent in battery characteristics in a wide temperature range from a low temperature to a high temperature. Therefore, the present invention is of great industrial value.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a cross section of an electrode plate constituting a power generating element of a nonaqueous electrolyte secondary battery according to Example 1 of the present invention. FIG. 2 is a diagram showing a cross-sectional structure of a non-aqueous electrolyte secondary battery according to Example 1 of the present invention. [Description of Signs] 1 Positive electrode mixture layer 2 Positive electrode current collector layer 3 Insulating material 4 Negative electrode current collector layer 5 Negative electrode mixture layer 6 Isolator 20 Electrode plate 30 Power generation element 100 Nonaqueous electrolyte secondary battery

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-8-45545 (JP, A) JP-A-11-339851 (JP, A) JP-A-11-283667 (JP, A) JP-A-11-283667 67266 (JP, A) JP-A-11-260401 (JP, A) JP-A-11-121032 (JP, A) JP-A-11-339849 (JP, A) JP-A-7-122296 (JP, A) JP-A-8-96852 (JP, A) JP-A-9-199173 (JP, A) JP-A-7-220756 (JP, A) JP-A-6-52887 (JP, A) JP-A-9-199179 (JP, A) JP-A-9-199178 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 10/40 H01M 4/02 H01M 4/58

Claims (1)

(57) [Claim 1] A battery container made of a metal-laminated resin sheet is provided with a wound flat power generation element having a positive electrode, a separator, and a negative electrode made of a carbon material, and an electrolytic solution. Yes,
The solvent of the electrolytic solution is a mixed solvent of vinylene carbonate, propylene carbonate, and a chain carbonate ,
The composition of the above vinylene carbonate with respect to all solvents is Form A
%, Based on the total solvent of the propylene carbonate.
If the composition is B volume%, 10 ≦ (A + B) ≦ 50
(However, A ≠ 0 and B ≠ 0) and 3 ≦ A ≦ 20
Nonaqueous electrolyte battery, characterized in that that.