JP2003086252A - Lithium secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lithium secondary battery, of which the manufacturing costs are reduced while its manufacturing is simple, and which is excellent in the cycle characteristic. SOLUTION: It is the lithium secondary battery equipped with an electrode body 1, in which a positive-electrode board 2 and a negative-electrode board 3 are wound or laminated through an insulator. The insulator 15 is formed in one body on the surface, which should abut the other electrode board 3 of at least one electrode board 2 of the electrode body 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithium secondary battery which has a reduced manufacturing cost and is excellent in battery performance, particularly cycle characteristics.

[0002]

2. Description of the Related Art In recent years, a lithium secondary battery has been widely used as a small and chargeable secondary battery having a large energy density, which serves as a power source for electronic devices such as portable communication devices and notebook personal computers. Is starting to appear. In addition, as interest in resource saving and energy saving is increasing against the backdrop of international protection of the global environment, lithium secondary batteries are being used for motor drive of electric vehicles, which are being actively introduced into the market in the automobile industry. It is also expected as a means for effectively using electric power by storing a battery or night electric power, and commercialization of a large-capacity lithium secondary battery suitable for these applications is urgently needed.

In a lithium secondary battery, a lithium transition metal composite oxide or the like is generally used as a positive electrode active material, and a carbonaceous material such as hard carbon or graphite is used as a negative electrode active material. Since the reaction potential of the lithium secondary battery is as high as about 4.1 V, it is not possible to use a conventional aqueous electrolyte solution as an electrolyte solution. Therefore, a non-aqueous electrolyte prepared by dissolving a lithium compound, which is an electrolyte, in an organic solvent is used. A liquid is used. Then, the charging reaction causes Li ⁺ in the positive electrode active material to
It occurs by passing through the non-aqueous electrolyte to the negative electrode active material and being captured, and the reverse battery reaction occurs during discharge.

In a lithium secondary battery having a relatively large capacity, as shown in FIG. 3, positive and negative electrode plates 2 and 3 (electrode leads 5 and 6 (positive electrode lead 5 and negative electrode lead 6) are attached. A wound-type electrode body 1 formed by winding the positive electrode plate 2 and the negative electrode plate 3) around the outer periphery of the winding core 13 with the separator 4 interposed therebetween so as not to contact each other is preferably used.

Here, the separator 4 interposed between the positive electrode plate and the negative electrode plate is a member made of a porous film such as polyolefin, which is capable of impregnating a non-aqueous electrolytic solution and at the same time ion (Li ⁺ ) Movement is not hindered, and
It is a constituent member having a function of insulating the positive electrode and the negative electrode.

[0006]

Usually, although slightly, a phenomenon in which a separator interferes with the movement of ions (Li ⁺ ) and causes polarization can occur. Polarization tends to become remarkable especially when high-current charging / discharging is applied, but damage is accumulated in the battery especially when charging / discharging is repeated many times, and the charging / discharging cycle characteristics of the battery (repeating charging / discharging It is also assumed that the battery capacity change characteristic due to the above (hereinafter referred to as “cycle characteristic”) is deteriorated.

In general, when a separator having a large pore size is used, the polarization becomes small, so that the cycle characteristics are improved. Therefore, if the pore size of the separator is increased in order to improve the cycle characteristics, the shape of the separator gradually becomes difficult to maintain, and it becomes difficult to handle the separator as an independent member and to sandwich it between the electrode plates. That is,
Since it is necessary for the separator to maintain its shape by itself, there is a limit to improving the cycle characteristics of the battery by increasing the pore size of the separator.

A battery may be required to be charged and discharged with a large current depending on the purpose of use and the situation of use. For example, for lithium secondary batteries with a relatively large capacity, such as those used in vehicles and for storage of electric power, charging and discharging of a large current many times are repeated over a long period of time, which suppresses deterioration of the cycle characteristics of the battery and shortens the battery life. Prolonging life is an important issue. Therefore, the industry is demanding the development of a battery that eliminates such inconvenience and has a long life even under severe usage conditions.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is that the manufacturing is simple, the manufacturing cost is reduced, and the cycle characteristics are excellent. To provide a lithium secondary battery.

[0010]

Means for Solving the Problems That is, according to the present invention, there is provided a lithium secondary battery including an electrode body in which a positive electrode plate and a negative electrode plate are wound or laminated with an insulator interposed between the positive electrode plate and the negative electrode plate. Provided is a lithium secondary battery in which the insulator is integrally formed on a surface of at least one electrode plate of the body to be in contact with the other electrode plate.

In the present invention, the insulator is preferably an organic polymer compound or an inorganic powder material, or a mixture of an organic polymer compound and an inorganic powder material.

Further, in the present invention, the organic polymer compound is preferably at least one selected from the group consisting of a polyethylene oxide resin, a polyolefin resin, and a fluorine resin, and further, the organic polymer compound is It is preferably a foamed resin.

In the present invention, the inorganic powder is preferably at least one selected from the group consisting of alumina, zirconia, titania, magnesia, and calcia.

Further, in the present invention, the pore size of the insulator is preferably 1 μm or more, and 10 to 100 μm.
Is more preferable.

The lithium secondary battery of the present invention is suitably used for a large battery having a battery capacity of 2 Ah or more, and is also used as a power source for driving a motor of an electric vehicle or a hybrid electric vehicle that frequently discharges a large current. It is preferably used.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments. It should be understood that design changes, improvements, etc. can be appropriately made based on the knowledge of.

The present invention is a lithium secondary battery including an electrode body in which a positive electrode plate and a negative electrode plate are wound or laminated with an insulator interposed therebetween, and the other electrode plate in at least one electrode plate of the electrode body. The insulator is integrally formed on the surface to be contacted with. The details will be described below.

FIG. 1 is a view showing an embodiment of a wound electrode body used in a lithium secondary battery according to the present invention, where (a) is a perspective view of the whole and (b) is (a). It is an enlarged view of part A. On the other hand, FIG. 3 is a perspective view showing an embodiment of a wound electrode body used in a conventional lithium secondary battery.
In the wound-type electrode body shown in FIG. 1, a state in which the electrode plate integrated insulator 15 is provided on each surface of the positive electrode plate 2 and the negative electrode plate 3 that is in contact with the other electrode body is It is shown. On the other hand, the conventional wound electrode body 1 shown in FIG.
In Fig. 1, the separator 4 is provided as an independent component. That is, in the electrode body used in the lithium secondary battery of the present invention, there is no separator which has conventionally existed as an independent component separate from the electrode plate, and the insulator is formed integrally with the electrode plate. .

Therefore, in the lithium secondary battery of the present invention, it is possible to increase the pore size of the insulator as compared with the pore size of the separator used in the conventional lithium secondary battery. It is possible to further suppress the occurrence of polarization. Therefore, the lithium secondary battery of the present invention is superior in cycle characteristics to the conventional lithium secondary battery including the separator that is an independent component.

Further, the separator is one of the relatively expensive members among the constituent members of the lithium secondary battery, and the method of forming the insulator on the surface of the electrode plate is the same as in the production of ordinary lithium secondary batteries. Since it can be easily introduced into the process, the lithium secondary battery of the present invention that does not use a separator is also considered in terms of manufacturing cost.

Further, in the lithium secondary battery of the present invention, if the insulator is formed only on the surface of at least one of the electrode plates constituting the electrode body, the positive electrode plate and the negative electrode plate are effectively insulated from each other. However, it may be formed on the surfaces of the two electrode plates which are in contact with each other. That is,
Considering the physical and chemical properties of the formed insulator,
The surface on which the insulator is formed is appropriately determined.

The lithium secondary battery of the present invention is not limited to the use of the wound electrode body 1 shown in FIG. 1 described above, but may be of the type such as the laminated electrode body 7 shown in FIG. And other electrode bodies may be used. That is,
The lithium secondary battery of the present invention has a positive electrode plate, a negative electrode plate, or an electrode body having an electrode body on which an electrode plate-integrated insulator is formed on both surfaces. It is not limited.

The insulator formed on the surface of the positive electrode plate or the negative electrode plate of the lithium secondary battery of the present invention, or both of the electrode plates is preferably an organic polymer compound or an inorganic powder material. This is because these materials can effectively insulate both electrode plates, and can easily form an insulator integrated with the electrode plates. Further, in the present invention, from the same viewpoint, it is also preferable that the insulator is a mixture of an organic polymer compound and an inorganic powder material.

Further, in the present invention, the organic polymer compound is preferably at least one selected from the group consisting of polyethylene oxide resins, polyolefin resins, and fluorine resins, and the inorganic powder material Is preferably at least one selected from the group consisting of alumina, zirconia, titania, magnesia, and calcia. The thickness of the insulator formed of these materials can be adjusted arbitrarily, and
This is because it is cheap and easily available. In addition, from the viewpoint of ease of adjusting the thickness of the above-mentioned insulator and availability, the organic polymer compound is preferably a foamed resin.

The lithium secondary battery of the present invention is characterized in that the insulator is formed integrally with the electrode plate on the surface of the electrode plate, and there are no restrictions on other materials or battery structure. There is no. The main members and structure of the lithium secondary battery will be outlined below.

First, the structure of the wound electrode body 1 shown in FIG. 1 will be described as an example. The positive electrode plate 2 is manufactured by applying a positive electrode active material on both surfaces of a current collecting substrate.
As the current collector substrate, a metal foil such as an aluminum foil or a titanium foil having good corrosion resistance against a positive electrode electrochemical reaction is used, but a punching metal or a mesh (mesh) may be used instead of the foil. As the positive electrode active material, lithium manganate (LiMn ₂ O ₄ ), lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (Li) is used.
Although a lithium transition metal composite oxide such as NiO ₂ ) is preferably used, lithium manganate is particularly preferable in the present invention, and the resistance of the positive electrode active material layer is higher than that when other positive electrode active material is used. Can be made smaller. It is preferable to add fine carbon powder such as acetylene black to these positive electrode active materials as a conductive additive.

The lithium manganate is not limited to such a stoichiometric composition (stoichiometric composition), and a general formula in which a part of Mn is replaced with one or more other elements is given. _{LiM X Mn 2-X O 4} (M is a substituted element, X represents. the amount of substitution) lithium manganate represented by also suitably used. In the lithium manganate that has undergone such element substitution, the Li / Mn ratio exceeds 0.5.

The substituting element M is listed below by the element symbols, but Li, Fe, Mn, Ni, Mg, Zn,
B, Al, Co, Cr, Si, Ti, Sn, P, V, S
b, Nb, Ta, Mo, and W can be mentioned, and theoretically, Li has a +1 valence, and Fe, Mn, Ni, Mg, and Zn have +.
Divalent, B, Al, Co, Cr +3, Si, Ti, S
n is +4 valence, P, V, Sb, Nb, Ta is +5 valence, M
o and W are +6 valent ions and are elements that form a solid solution in LiMn ₂ O ₄ . However, when Co and Sn are +2 valence, and when Fe, Sb and Ti are +3 valence, M
+3 valence for n, +4 valence for Cr, + for Cr
It may be tetravalent or +6.

Therefore, the various substitutional elements M may exist in a state having mixed valences, and the amount of oxygen needs to be 4 as represented by the stoichiometric composition. Alternatively, it may be deficient or excessively present within the range for maintaining the crystal structure.

The positive electrode active material is applied by coating a current collector substrate with a slurry or paste prepared by adding a solvent, a binder and the like to positive electrode active material powder using a roll coater method or the like.
It is performed by drying, and thereafter, a pressing process or the like is performed if necessary.

The negative electrode plate 3 can be manufactured in the same manner as the positive electrode plate 2. As the current collector substrate of the negative electrode plate 3, a metal foil such as a copper foil or a nickel foil having a good corrosion resistance against a negative electrode electrochemical reaction is preferably used. As the negative electrode active material, an amorphous carbonaceous material such as soft carbon or hard carbon, or highly graphitized carbonaceous powder such as artificial graphite or natural graphite is used.

The lithium secondary battery of the present invention has an electrode plate-integrated insulator formed on the surface of the electrode plate. Examples of the material of the formed electrode plate-integrated insulator include organic polymer compounds such as polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVD).
F), polyethylene (PE) and the like, or a mixture thereof, and alumina, zirconia, titania, magnesia, calcia, etc., or a mixture thereof are preferably used as an example of the inorganic powder material. Furthermore, it is also preferable to appropriately mix these organic polymer compounds and inorganic powders.

The material for forming the above-mentioned electrode plate-integrated insulator is made into a molten material by, for example, heat treatment,
Dispersion, a solution, or a preparation such as a paste is obtained, and in the obtained preparation, an electrode plate on which an electrode plate-integrated insulator is to be formed is immersed, or a suitable device such as a sprayer, After spraying and coating the preparation on the surface of the electrode plate using a coating machine, etc., leave it at room temperature or
The electrode plate-integrated insulator can be formed by drying under an appropriate heating condition.

The thickness of the electrode plate-integrated insulator to be formed can be easily adjusted by, for example, changing the concentration of the preparation, the immersion time of the electrode plate, or the like. The pore size of the electrode plate-integrated insulator can also be adjusted by, for example, changing the concentration of the preparation, the immersion time of the electrode plate, or the like. In addition, the size of the pore diameter is the pore diameter (0.1 to 1 μm) of the conventionally used separator.
A pore size larger than that is preferable from the viewpoint of suppressing the occurrence of polarization and providing a lithium secondary battery having excellent cycle characteristics. Specifically, it is preferably 1 μm or more, and more preferably 10 to 100 μm. If it exceeds 100 μm, the possibility of short circuit due to contact between the electrode plate particles increases, which is not preferable.

During the winding operation of the electrode plates 2 and 3 having the electrode plate integrated insulator 15 formed on the surface thereof, the electrode active material is not coated on the electrode plates 2 and 3 and the electrode plate 1 and 3 are not coated. The electrode leads 5 and 6 are attached to the exposed portions of the current collecting substrate on which the body-type insulator 15 is not formed. As the electrode leads 5 and 6, foil-shaped ones made of the same material as the current collecting substrates of the electrode plates 2 and 3 are preferably used. To attach the electrode leads 5 and 6 to the electrode plates 2 and 3,
It can be performed using ultrasonic welding or spot welding.

Next, the non-aqueous electrolyte used in the lithium secondary battery of the present invention will be described. Examples of the solvent include carbonate-based ones such as ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC) and propylene carbonate (PC), and single solvents or mixed solvents such as γ-butyrolactone, tetrahydrofuran and acetonitrile. It is preferably used.

Examples of the electrolyte include lithium complex fluoride compounds such as lithium hexafluorophosphate (LiPF ₆ ) and lithium borofluoride (LiBF ₄ ), or lithium halides such as lithium perchlorate (LiClO ₄ ). One kind or two or more kinds are dissolved in the above-mentioned organic solvent (mixed solvent) and used. In particular, it is preferable to use LiPF ₆ which does not easily undergo oxidative decomposition and has high conductivity of the non-aqueous electrolyte.

When assembling the lithium secondary battery,
First, the wound electrode body 1 thus prepared is inserted into the battery case and held at a stable position while ensuring electrical continuity between the terminals for taking out an electric current and the electrode leads 5 and 6.
Then, a lithium secondary battery can be manufactured by impregnating the above-mentioned non-aqueous electrolyte and sealing the battery case.

As described above, the lithium secondary battery according to the present invention has been described with reference to the exemplary embodiment mainly using the wound electrode body. However, the present invention is not limited to the above-described exemplary embodiment. It goes without saying that it is not limited. In addition, the lithium secondary battery according to the present invention is particularly preferably used for a large battery having a battery capacity of 2 Ah or more, but it does not prevent application to a battery having such a capacity or less. Further, the lithium secondary battery of the present invention,
It is preferably used as an in-vehicle battery that takes advantage of the features of large capacity, low cost, and high reliability, and further preferably used for an electric vehicle or a hybrid electric vehicle and for starting an engine that requires a high voltage. be able to.

[0040]

EXAMPLES The concrete results of the present invention will be described below. (Production of Electrode Plate) A positive electrode agent slurry prepared by adding LiMn ₂ O ₄ spinel as a positive electrode active material and adding 4% by mass of acetylene black as a conductive additive in an external ratio to the positive electrode active material was further added a solvent and a binder. A positive electrode plate was produced by coating both sides of an aluminum foil having a thickness of 20 μm to a thickness of about 100 μm. Further, graphite powder was applied as a negative electrode active material to both sides of a copper foil having a thickness of 10 μm so as to have a thickness of about 80 μm, to prepare a negative electrode plate.

Example 1 A polytetrafluoroethylene (PTFE) aqueous dispersion having a concentration of 10% by mass was prepared. The PTFE particles in the aqueous dispersion had a spherical shape, and the average particle diameter was 0.3 μm.
The above-mentioned positive electrode plate and negative electrode plate were immersed in this aqueous dispersion. Then, by drying at 100 ° C. for 12 hours in a dryer, a film-shaped electrode plate integrated insulator was formed. In addition, the film thickness of the formed electrode plate integrated insulator is
Both of the electrode plates had a thickness of about 50 μm on one side, and when the electric resistance was measured in the thickness direction of the film, both electrodes had a resistance of 200 MΩ or more.

A wound electrode body 1 as shown in FIG. 1 was produced using the produced positive and negative electrode plates on which the electrode plate integrated insulator was formed. This was housed in a battery case and filled with a non-aqueous electrolyte, and the battery case was sealed to produce a lithium secondary battery. The non-aqueous electrolyte is EC and D
LiPF ₆ as electrolyte in 1 volume mixed solvent of EC
It was prepared by dissolving so as to have a concentration of mol / l.

Example 2 An N-methyl-2-pyrrolidone (NMP) solution of polyvinylidene fluoride (PVDF) having a concentration of 5% by mass was prepared. This solution was sprayed on the positive electrode plate and the negative electrode plate described above. Then, in the dryer 120
By drying at 12 ° C. for 12 hours, a film-shaped electrode plate integrated insulator was formed. The film thickness of the formed electrode plate-integrated insulator was about 50 μm on each side of both electrode plates, and the electric resistance was measured in the thickness direction of the film.
It was 0 MΩ or more. Using the produced positive / negative electrode plate having the electrode plate-integrated insulator formed thereon, a lithium secondary battery was produced by the same operation procedure as in the case of Example 1.

Example 3 Polyethylene (PE) was added to 13
It was melted at 0 ° C. and sprayed on the positive electrode plate and the negative electrode plate described above. Then, by cooling to room temperature, a film-shaped electrode plate integrated insulator was formed. The thickness of the formed electrode plate-integrated insulator is about 50 on each side of both electrode plates.
The electric resistance was measured in the thickness direction of the film, and both electrodes were 200 MΩ or more. Using the produced positive and negative electrode plates with the electrode plate integrated insulator formed,
A lithium secondary battery was produced by the same operation procedure as in the case of Example 1.

Example 4 An Al ₂ O ₃ aqueous dispersion having a concentration of 10% by mass was prepared. The average particle size of Al ₂ O ₃ particles in the aqueous dispersion was 10 μm. The above-mentioned positive electrode plate and negative electrode plate were immersed in this aqueous dispersion. Then, by drying at 100 ° C. for 12 hours in a dryer, a film-shaped electrode plate integrated insulator was formed. The film thickness of the formed electrode plate-integrated insulator was about 50 μm on both surfaces of both electrode plates, and the electric resistance was measured in the thickness direction of the film, and both electrodes were 200 MΩ or more. Using the produced positive / negative electrode plate having the electrode plate-integrated insulator formed thereon, a lithium secondary battery was produced by the same operation procedure as in Example 1.

Example 5 An N-methyl-2-pyrrolidone (NMP) solution of polyvinylidene fluoride (PVDF) having a concentration of 5% by mass was prepared, and Al ₂ O ₃ was mixed with the solution to 10% by mass. Then, a dispersion was prepared. The obtained dispersion was used to coat the positive electrode plate and the negative electrode plate described above using a coater. Then, by drying in a dryer at 120 ° C. for 12 hours, a film-shaped electrode plate integrated insulator was formed. The film thickness of the formed electrode plate-integrated insulator was about 50 μm on both surfaces of both electrode plates, and the electric resistance was measured in the thickness direction of the film, and both electrodes were 200 MΩ or more. Using the produced positive and negative electrode plates on which the electrode plate integrated type insulator was formed, Example 1 was used.
A lithium secondary battery was produced by the same operation procedure as in the above.

(Comparative Example 1) Example 1 except that a positive / negative electrode plate without forming an electrode plate-integrated insulator and a polyolefin separator (film thickness (one side): about 25 μm) were used as the insulator. A lithium secondary battery was produced by the same operation procedure as in the case of 1.

(Cycle Test) The cycle test was carried out by repeating the charge / discharge cycle shown in FIG. 4 as one cycle. That is, in one cycle, a battery in a charged state with a discharge depth of 50% was discharged for 9 seconds at a current of 100 A corresponding to 10 C (discharge rate), then paused for 18 seconds, then charged at 70 A for 6 seconds, and then at 18 A for 27 seconds. The battery was charged, and the pattern was set to bring the battery into a 50% charged state again. By finely adjusting the current value of the second charge (18 A), the deviation of the depth of discharge in each cycle was minimized. In addition, in order to know the change in battery capacity during this endurance test, the capacity was measured at a charge stop voltage of 4.1 V and a discharge stop voltage of 2.5 V at a current strength of 0.2 C, and the predetermined number of cycles was determined. The relative discharge capacity (%) was obtained from the value obtained by dividing the battery capacity in (times) by the initial battery capacity. The results of the cycle test on the batteries of Examples 1 to 5 and Comparative Example 1 are shown in Table 1 and FIG.

[0049]

[Table 1]

(Discussion) As is apparent from the results shown in Table 1 and FIG. 5, the batteries of Examples 1 to 5 according to the present invention are 2
It was found that a capacity retention rate of 80% or more was achieved after the 0000 cycle test, and that the cycle performance was extremely good as compared with the battery of Comparative Example 1. this is,
By replacing the separator used in the conventional lithium secondary battery with an electrode plate integrated insulator,
Since the pore size of the insulator separating the positive electrode plate and the negative electrode plate is increased, the movement of ions (Li ⁺ ) is not hindered,
That is, it is considered that the cycle life was improved as a result because the polarization was reduced.

[0051]

As described above, in the lithium secondary battery of the present invention, since the predetermined insulator is integrally formed on the surface of the electrode plate constituting the electrode body, the conventional insulator As compared with the separator used as, the pore size can be increased and the cycle characteristics are excellent. Further, the lithium secondary battery has a reduced manufacturing cost because it does not require a separator which is an independent component and can form an insulator by a simple operation procedure.

[Brief description of drawings]

1A and 1B are drawings showing an embodiment of a wound electrode body used in a lithium secondary battery according to the present invention, in which FIG. 1A is an overall perspective view, and FIG. 1B is an enlarged view of part A of FIG. It is a figure.

FIG. 2 is a perspective view showing an embodiment of a laminated electrode body used in the lithium secondary battery according to the present invention.

FIG. 3 is a perspective view showing an embodiment of a wound electrode body used in a conventional lithium secondary battery.

FIG. 4 is a graph showing a charge / discharge pattern in a cycle test.

FIG. 5 is a graph showing the results of a cycle test.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Wound type electrode body, 2 ... Positive electrode plate, 3 ... Negative electrode plate, 4 ... Separator, 5 ... Electrode lead, 6 ... Electrode lead, 7 ... Laminated electrode body, 8 ... Positive electrode plate, 9 ... Negative electrode plate, 10 … Separator,
11 ... Electrode lead, 12 ... Electrode lead, 13 ... Winding core, 1
5 ... Insulator integrated with electrode plate.

Continued front page    F term (reference) 5H029 AJ05 AJ14 AK03 AL06 AL07                       AM03 AM04 AM05 AM07 BJ02                       BJ12 BJ13 BJ14 CJ08 CJ22                       DJ16 EJ03 EJ12 HJ06 HJ19                 5H050 AA07 AA19 BA05 CA08 CA09                       CB07 CB08 DA02 DA03 EA01                       EA23 FA04 FA17 GA10 GA22                       HA06 HA19

Claims (12)

[Claims] 1. A lithium secondary battery comprising an electrode body in which a positive electrode plate and a negative electrode plate are wound or laminated with an insulator interposed therebetween, wherein at least one of the electrode plates is the other electrode plate. A lithium secondary battery, wherein the insulator is integrally formed on a surface to be contacted with. 2. The lithium secondary battery according to claim 1, wherein the insulator is an organic polymer compound or an inorganic powder material. 3. The lithium secondary battery according to claim 1, wherein the insulator is a mixture of an organic polymer compound and an inorganic powder material. 4. The lithium secondary battery according to claim 2, wherein the organic polymer compound is at least one selected from the group consisting of polyethylene oxide resin, polyolefin resin, and fluorine resin. 5. The lithium secondary battery according to claim 2, wherein the organic polymer compound is a foamed resin. 6. The inorganic powder material is alumina, zirconia,
The lithium secondary battery according to claim 2 or 3, which is at least one selected from the group consisting of titania, magnesia, and calcia. 7. The lithium secondary battery according to claim 1, wherein the insulator has a pore size of 1 μm or more. 8. The lithium secondary battery according to claim 1, wherein the insulator has a pore size of 10 to 100 μm. 9. A battery having a battery capacity of 2 Ah or more.
8. The lithium secondary battery according to any one of items 8. 10. The lithium secondary battery according to claim 1, which is a vehicle-mounted battery. 11. The lithium secondary battery according to claim 10, which is used in an electric vehicle or a hybrid electric vehicle. 12. The method according to claim 1, which is used for starting an engine.
The lithium secondary battery according to 0 or 11.