JP2001319639A - Battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable battery. SOLUTION: A lithium secondary battery 10a comprises a positive electrode current collector 2 and a separator 8, and provide active material 7a containing lithium oxide, polymer 7b, and conductive materials 7c arranged between the positive electrode current collector 2 and the separator 8. A volume of the polymer 7b based on the total volume of the positive active material 7a, the polymer 7b, and the conductive material 7c is 50 to 80%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery, and more particularly to a battery used for portable equipment such as a portable telephone.

[0002]

2. Description of the Related Art In recent years, with the spread of portable telephones and notebook personal computers, research on batteries used for them has been advanced. Secondary batteries which can be used repeatedly are used as these batteries.

[0003] Many of the secondary batteries currently used are nickel-cadmium batteries. However, this battery has the disadvantage that the electromotive force is small.

Therefore, development of a so-called lithium secondary battery using a lithium oxide as a positive electrode active material has been advanced.

FIG. 11 is a sectional view of a conventional lithium secondary battery. Referring to FIG. 11, lithium secondary battery 100
Are a package can 1, a positive electrode current collector 2, a negative electrode current collector 3, a negative electrode terminal 4, an insulator 5, a negative electrode active material layer 6, a positive electrode active material layer 107, a separator 8, Liquid 9.

[0006] An outer can 1 contains a positive electrode current collector 2, a negative electrode current collector 3, a negative electrode active material layer 6, a positive electrode active material layer 107, a separator 8 and an electrolytic solution 9.

The outer can 1 is made of an aluminum alloy, and the outer can 1 is provided with a through-hole, into which the negative electrode current collector 3 is inserted. An insulator 5 is provided between the outer can 1 and the negative electrode current collector 3, and the negative electrode current collector 3 and the outer can 1 are electrically insulated according to a so-called glass hermetic method. The portion projecting from the outer can 1 constitutes the negative electrode terminal 4. The outer can 1 functions as a positive electrode terminal.

A positive electrode current collector 2 is connected to the inner wall surface of the outer can 1. The positive electrode current collector 2 and the outer can 1 are connected by spot welding. The positive electrode current collector 2 is made of, for example, aluminum and has a thin plate shape. The positive electrode current collector 2 faces the negative electrode current collector 3, and the positive electrode active material layer 107, the separator 8, and the negative electrode active material layer 6 are provided between the negative electrode current collector 3 and the positive electrode current collector 2.

A positive electrode active material layer 107 is provided so as to be in contact with positive electrode current collector 2. For the positive electrode active material layer 107, for example, a material in which lithium and a transition metal are combined to form an oxide is used.

[0010] A separator 8 is provided in contact with the positive electrode active material layer 107. The separator 8 is made of an insulator, but the separator 8 is a porous body. Therefore, electrons and ions can pass through the separator 8 and move from the positive electrode active material layer 107 to the negative electrode active material layer 6 or from the negative electrode active material layer 6 to the positive electrode active material layer 107. The separator 8 functions to prevent direct contact between the positive electrode active material layer 107 and the negative electrode active material layer 6. The negative electrode active material layer 6 is provided so as to be in contact with the separator 8.
Metallic lithium can be used for the negative electrode active material layer 6.

A negative electrode current collector 3 is provided so as to be in contact with negative electrode active material layer 6. The negative electrode current collector 3 is made of a copper foil and has a thin plate shape. An electrolytic solution 9 is filled in the outer can 1. The electrolytic solution 9 is composed of an organic solution in order to prevent a reaction with lithium.

[0012]

The problems which occur in the conventional lithium secondary battery will be described below. When the conventional lithium secondary battery 100 is used and the electromotive force decreases,
Charging is performed. In this case, a relatively high potential is applied to the negative electrode terminal 4, and a relatively low potential is applied to the outer casing 1, which is the positive electrode terminal. As a result, a current flows from the negative electrode current collector 3 to the positive electrode current collector 2. In addition, when the current flows as described above, lithium ions in the positive electrode active material layer 107 are precipitated as lithium in the negative electrode active material layer 6. When charging is completed, the lithium secondary battery 100 can be used again.

In normal charging, the outer can 1 serving as a positive electrode terminal
The potential difference between the negative electrode terminal 4 and the negative terminal 4 is about 4 V, and a larger potential difference is applied to the negative terminal 4 and the outer can 1.
So-called overcharging may be performed. In this case, the oxide of the composite of lithium and the transition metal constituting the positive electrode active material layer 107 has a high electric resistance.
7 does not flow much in the inside of the cathode active material layer 107.
A lot of current flows on the surface of the. Accordingly, heat is generated on the surface of the positive electrode active material layer 107, and the oxide of the composite of lithium and the transition metal constituting the positive electrode active material layer 107 is inactivated,
There was a problem that the battery failed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to provide a highly reliable battery that does not cause a failure.

[0015]

A battery according to the present invention comprises a positive electrode current collector layer, a positive electrode active material layer, an insulating layer, a negative electrode active material layer, and a negative electrode current collector layer sequentially laminated. Formed. The positive electrode active material layer includes a positive electrode active material containing a lithium metal oxide, a polymer, and a conductive material. The ratio of the volume of the polymer to the total volume of the positive electrode active material, the polymer, and the conductive material is 50% or more and 80% or less.

In this specification, "lithium metal oxide"
The term refers to an oxide obtained by combining lithium and a metal.

In the battery thus configured, since the positive electrode active material layer contains a polymer, the electric resistance between the positive electrode current collector layer and the insulating layer is substantially uniform. Therefore, a large amount of current does not flow to only a part, and the lithium metal oxide which is an active material is not inactivated. As a result, failure of the battery can be prevented.

The ratio of the volume of the polymer to the total volume of the positive electrode active material, the polymer and the conductive material is 50% or more and 80% or more.
%, The capacity of the battery does not decrease even when the charge / discharge cycle is repeated, and a high capacity can be maintained. If the ratio of the volume of the polymer to the total volume of the positive electrode active material, the polymer, and the conductor is less than 50%,
Since the proportion of the polymer is small, the current easily flows only in a part. Therefore, when the charge / discharge cycle is repeated, the capacity of the battery is reduced because the positive electrode active material is inactivated at that portion. If the above ratio exceeds 80%, the ratio of the positive electrode active material becomes small, so that the capacity of the battery decreases. for that reason,
The proportion of the polymer must be 50% or more and 80% or less.

Further, since the positive electrode active material layer contains a conductive material, the electric resistance between the positive electrode current collector layer and the insulating layer can be reduced. As a result, the internal resistance of the battery can be reduced, and the capacity of the battery can be improved.

Preferably, the battery further includes an electrolyte surrounding the positive electrode current collector layer. The polymer includes a portion that dissolves in the electrolyte. In this case, since the polymer contains a portion that dissolves in the electrolyte, the electrolyte is gelled and the electrolyte does not move, so that the safety is improved.

[0021] Preferably, the positive electrode active material layer further contains ceramic powder. In this case, the surface area of the polymer increases because the ceramic powder contacts the polymer and deforms the polymer. As a result, the polymer is more uniformly dispersed, and the reliability of the battery can be further improved.

Preferably, the positive electrode active material layer contains a binder for bonding the conductive material and the polymer. In this case, since the conductive material does not separate from the polymer, the electric resistance between the positive electrode current collector layer and the insulating layer can be reduced even when the battery is used for a long time.

More preferably, the ratio of the volume of the polymer to the positive electrode active material is relatively large on the insulating layer side and relatively small on the positive electrode current collector layer side. In this case, by increasing the volume ratio of the polymer on the insulating layer side, it is possible to prevent current concentration on the insulating layer side and to prevent inactivation of the positive electrode active material.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a sectional view of a lithium secondary battery according to Embodiment 1 of the present invention. Referring to FIG. 1, a lithium secondary battery 10a includes an outer can 1
A positive electrode current collector 2 as a positive electrode current collector layer; a negative electrode current collector 3 as a negative electrode current collector layer; a negative electrode terminal 4;
, A negative electrode active material layer 6, a positive electrode active material layer 7, a separator 8 as an insulating layer, and an electrolytic solution 9.

A positive electrode current collector 2, a negative electrode current collector 3, a negative electrode active material layer 6, a positive electrode active material layer 7, a separator 8 and an electrolytic solution 9 are housed in an outer can 1.

The outer can 1 is made of an aluminum alloy, extends in the longitudinal direction, and has a substantially rectangular parallelepiped shape. The outer can 1 functions as a housing for the lithium secondary battery 10a. The outer can 1 is provided with a through hole, and the insulator 5 is fitted into the through hole.

A negative electrode current collector 3 is provided inside the outer can. The negative electrode current collector 3 is inserted into a through hole provided on one end surface of the outer can 1, and a part thereof extends so as to protrude from the one end surface of the outer can 1, and the protruding portion forms the negative electrode terminal 4. I do.

A positive electrode current collector 2 is provided so as to be in contact with the other end surface of the outer can 1. The positive electrode current collector 2 is made of an aluminum alloy, and is electrically connected to the outer can 1 by spot welding. The positive electrode current collector 2 has a single thin plate shape.

The negative electrode current collector 3 and the positive electrode current collector 2 are
The negative electrode active material layer 6, the separator 8, and the positive electrode active material layer 7 are provided between them. It is also possible to make the negative electrode current collector 3 and the positive electrode current collector 2 face each other in a spiral shape and increase the facing area thereof to increase the capacity of the battery.

A positive electrode active material layer 7 is provided on the surface of the positive electrode current collector 2. The positive electrode active material layer 7 includes a positive electrode active material that is an oxide of lithium, a polymer, and a conductive material.

A separator 8 is provided in contact with the positive electrode active material layer 7. The separator 8 is made of an insulating material. The separator 8 has a porous structure, and ions and electrons can pass through holes in the separator. Therefore, ions and electrons can move from the positive electrode active material layer 7 to the negative electrode active material layer 6 or from the negative electrode active material layer 6 to the positive electrode active material layer 7.

The negative electrode active material layer 6 is provided so as to be in contact with the separator 8. Negative electrode active material layer 6 contains, for example, metallic lithium.

Note that a laminated film may be used instead of the outer can 1. In this case, the positive electrode current collector 2 and the negative electrode current collector 3 are respectively taken out from the laminate film. Further, copper, nickel, iron, aluminum, or the like can be used as the negative electrode current collector 3.

Further, the positive electrode current collector 2 and the negative electrode current collector 3
Some kind of insulating member may be provided between the positive electrode current collector 2 and the negative electrode current collector 3 and the outer can 1 in order to prevent direct contact between the outer can 1 and the outer can 1.

When the outer can 1 is made of iron,
The positive electrode current collector 2 is projected from one end face of the outer can 1, and the negative electrode current collector 3 is electrically connected to the outer can 1.

FIG. 2 is an enlarged sectional view showing a portion surrounded by a dotted line II in FIG. Referring to FIG. 2, a lithium secondary battery 10a according to the present invention includes a positive electrode current collector 2;
The battery includes a separator and a positive electrode active material layer disposed between the positive electrode current collector and the separator. Positive electrode active material layer 7
Is composed of a positive electrode active material 7a containing a lithium metal oxide, a polymer 7b for dispersing a current, and a conductive material 7c for reducing the electric resistance of the positive electrode active material layer 7.

The positive electrode active material 7a is made of LiMn ₂ O ₄ , Li ₂
It can be composed of Mn ₄ O ₉ , LiMnO ₂ , Li ₂ MnO ₃ or a mixture thereof. In addition, the positive electrode active material 7a
Can be composed of LiFeO ₂ , LiFe ₂ O ₄ , Li ₂ FeO ₃ or a mixture thereof. The positive electrode active material 7a is made of LiCoO ₂ , LiCo ₂ O ₄ , Li ₂ CoO
₃ or a mixture thereof. Further, the positive electrode active material 7a is made of LiTiO ₂ , LiTi ₂ O ₄ ,
It can be composed of Li ₂ TiO ₃ or a mixture thereof.

As the polymer 7b, a methacrylic acid-based polymer such as polymethyl methacrylate, an acrylic acid-based polymer such as polyacrylonitrile, polyvinylidene fluoride, polyethylene glycol, or the like can be used. The polymer 7b includes a portion that dissolves in the electrolytic solution 9 and dissolves in the electrolytic solution to cause the electrolytic solution 9 to gel. Further, the particle diameter of the particles of the polymer 7b can be 0.1 to 5 μm. The particle size of polymethyl methacrylate is 0.25 μm, the particle size of polyacrylonitrile is 3 μm, the particle size of polyvinylidene fluoride is 0.3 to 3 μm, and the particle size of polyethylene glycol is 3
μm. The particle size of the polymer 7b is smaller than the particle size of the positive electrode active material 7a. The polymer 7b is dispersed between the positive electrode active materials 7a. The positive electrode active material 7 a forms the skeleton of the positive electrode active material layer 7.

In the positive electrode active material layer 7 between the positive electrode current collector 2 and the separator 8, a conductive material 7c is dispersed. The conductive material 7c is made of acetylene black having a particle size of 1 to 5 μm. It is preferable that the conductive material 7c has low electric resistance and is chemically stable.
The particle size of the conductive material 7c made of acetylene black is smaller than the particle size of the positive electrode active material 7a.

The method for producing the positive electrode active material layer 7 includes the following method. First, LiMn ₂ O ₄ , LiMnO
_2. A positive electrode active material such as Li ₂ MnO ₃ , a polymer, and acetylene black are mixed.

Next, the mixture is impregnated with an electrolyte solution having a temperature of 10 to 150 ° C., and the polymer is gelled and fired. After that, firing is performed at a temperature of 400 ° C. or lower in an air atmosphere to form the positive electrode active material layer 7. The mixture may be baked at a temperature of 400 ° C. or lower without impregnating the electrolyte with the electrolyte.

As the electrolytic solution 9, a mixed solution of propylene carbonate (PC) and dimethyl ether (DME) can be used. Further, as the electrolytic solution 9, a mixed solution of ethylene carbonate (EC) and dimethyl carbonate (DMC) can be used.

The relationship between the volume of the polymer in the positive electrode active material layer 7 and the charge / discharge capacity of the lithium secondary battery 10a as shown in FIG. 1 was examined. In the lithium secondary battery 10a as shown in FIG. 1, samples were prepared in which the volume of the polymer 7b was variously changed with respect to the total volume of the positive electrode active material 7a, the polymer 7b, and the conductive material 7c constituting the positive electrode active material layer. . For these samples,
In each case, the capacity of the battery was measured. Next, these samples were repeatedly charged and discharged 300 times, and the capacity after that was examined. For each sample, it was examined how much the capacity of the battery after the charge / discharge was performed 300 times was lower than the capacity of the battery before the charge / discharge was performed 300 times. The result is shown in FIG.

The “rate of change in charge / discharge capacity after 300 cycles” on the vertical axis in FIG. 3 is a value obtained by dividing the capacity of the battery after 300 cycles of charge / discharge by the capacity of the battery before 300 cycles of charge / discharge. Yes, if this value becomes 1, it indicates that the capacity of the battery does not change even if charging and discharging are repeated 300 times. FIG. 3 shows that if the ratio of the volume of the polymer to the total volume of the positive electrode active material, the polymer and the conductive material is 50% or more, 300
It can be seen that the capacity of the battery does not change even after repeated charging and discharging.

Next, the relationship between the volume of the polymer in the positive electrode active material layer and the capacity of the battery was determined. That is, samples were prepared in which the volume of the polymer was variously changed with respect to the total volume of the positive electrode active material 7a, the polymer 7b, and the conductive material 7c constituting the positive electrode active material layer 7. The battery capacity was measured for these samples. FIG. 4 shows the results.

FIG. 4 shows that when the volume ratio of the polymer exceeds 80%, the capacity of the battery decreases. Therefore, in the present invention, the ratio of the volume of the polymer to the total volume of the positive electrode active material, the polymer, and the conductive material is set to 5 in order to maintain the battery capacity at a high level even when the charge / discharge cycle is repeated.
It turned out that it is necessary to set it to 0% to 80%.

Therefore, in the product of the present invention, the positive electrode active material 7
a, the ratio of the volume of the polymer 7b to the total volume of the polymer 7b and the conductive material 7c is 50% or more and 80% or less.

The lithium secondary battery 1 configured as described above
In the case of 0a, first, since the polymer 7b is contained in the positive electrode active material 7a, the electric resistance can be made uniform over the entire positive electrode active material 7a, so that the current does not concentrate on a part. As a result, the oxide of lithium, which is the positive electrode active material, is not inactivated, and battery failure can be prevented. Furthermore, since the ratio of the volume of the polymer is optimized according to the data shown in FIGS. 3 and 4, the lithium secondary battery 10a
Of the battery can be kept high, and the capacity of the battery does not decrease even if the charge / discharge cycle is repeated. Further, since acetylene black is included as a conductive material, the internal resistance of the lithium secondary battery 10a can be reduced.

(Embodiment 2) FIG. 5 is a sectional view of a lithium secondary battery according to Embodiment 2 of the present invention. FIG. 6 is an enlarged sectional view showing a portion surrounded by a dotted line VI in FIG. Referring to FIGS. 5 and 6, lithium secondary battery 10 b differs from lithium secondary battery 10 a shown in FIG. 2 in that ceramic particles 7 d are provided between positive electrode current collector 2 and separator 8. different.

The ceramic particles 7d are composed of hard particles such as alumina, aluminum nitride, etc.
To increase the surface area of the polymer 7b. The ceramic particles 7d preferably have non-rounded corners in order to deform the polymer 7b. The ceramic particles 7 d are dispersed throughout the positive electrode active material layer 7. The particle size of the ceramic particles 7d can be 0.1 to 0.9 μm.

The lithium secondary battery 1 configured as described above
0b has the same effect as the lithium secondary battery 10a according to the first embodiment.

Further, the polymer 7b is deformed by the action of the ceramic particles 7d to increase its surface area, so that the polymer 7b can be more uniformly dispersed.
Thereby, the capacity (output) of the battery can be increased. Specifically, when the volume of the polymer 7b in the positive electrode active material layer 7 is 50%, the lithium secondary battery 10b
Can be 160 Wh / kg.

(Embodiment 3) FIG. 7 is a sectional view of a lithium secondary battery according to Embodiment 3 of the present invention. FIG. 8 is an enlarged sectional view showing a portion surrounded by a dotted line VIII in FIG. Referring to FIGS. 7 and 8, in lithium secondary battery 10c, binder 7e for bonding conductive material 7c and polymer 7b between positive electrode current collector 2 and separator 8
Is different from the lithium secondary battery 10b shown in FIGS. 5 and 6. The binder 7e has a particle size of 1 to
It consists of 5 μm polyvinylidene fluoride. Binder 7e
Is made of an organic material having good adhesion to other substances, and is deformed and adheres to other particles.

The lithium secondary battery 1 configured as described above
0c has the same effect as the lithium secondary battery 10b shown in the second embodiment. Further, since the binder 7e exists, the conductive material 7c does not separate from the polymer 7b. Therefore, the electric resistance between the separator 8 and the positive electrode current collector 2 is further reduced, and the lithium secondary battery 10c
Can be reduced, and the capacity of the battery can be improved. Specifically, the positive electrode active material 7
When the volume ratio of a is 50%, the capacity per unit mass of the lithium secondary battery 10c can be 170 Wh / kg.

(Embodiment 4) FIG. 9 is a sectional view of a lithium secondary battery according to Embodiment 4 of the present invention. Referring to FIG. 9, lithium secondary battery 10 d differs from lithium secondary battery 10 a shown in FIG. 1 in that positive electrode surface layer 17 is provided between separator 8 and positive electrode active material layer 7. The positive electrode surface layer 17 also contains a lithium metal oxide acting as a positive electrode active material.

For example, the volume ratio between the positive electrode active material and the polymer in the positive electrode active material layer 7 is 50:50, and the positive electrode surface layer 1
The volume ratio between the positive electrode active material and the polymer in 7 is 20:80. As described above, the volume ratio of the polymer to the positive electrode active material is relatively large on the separator 8 side and relatively small on the positive electrode current collector 2 side. The positive electrode surface layer 17 is interposed between the positive electrode active material layer 7 and the separator 8. The positive electrode surface layer 17 is sufficiently thinner and thinner than the positive electrode active material layer 7.

The thus configured lithium secondary battery 1
0d has the same effect as the lithium secondary battery 10a described in the first embodiment. Furthermore, since the ratio of the polymer on the side of the separator 8 is large, the electric resistance in this portion can be made more uniform. As a result, the failure of the battery can be more effectively prevented without inactivating the positive electrode active material near the separator 8.

(Fifth Embodiment) FIG. 10 is a sectional view of a lithium secondary battery according to a fifth embodiment of the present invention.
Referring to FIG. 10, lithium secondary battery 10e has a structure in which a polymer layer 27 containing no positive electrode active material is provided between positive electrode active material layer 7 and separator 8, and thus lithium secondary battery 10e shown in FIG. Different from battery 10d. The polymer layer 27 does not contain any positive electrode active material. Therefore, the volume ratio of the polymer to the positive electrode active material is relatively large on the separator 8 side and relatively small on the positive electrode current collector 2 side. The polymer layer 27 is interposed between the positive electrode active material layer 7 and the separator 8. The polymer layer 27 is sufficiently thinner and thinner than the positive electrode active material layer 7.

The lithium secondary battery 1 configured as described above
0e, the lithium secondary battery 10 according to Embodiment 5
It has the same effect as d.

Although the embodiment of the present invention has been described above, the embodiment shown here can be variously modified. First, lithium oxide was described as a positive electrode active material of a lithium secondary battery, but it can be manufactured by various methods. For example, when constituting a positive electrode active material composed of an oxide of lithium and manganese, MnO ₂ and LiOH are reacted to form an oxide of lithium and manganese (LiMnO). At this time, the ratio of lithium and manganese in the oxide of lithium and manganese (LiMnO) can be changed by variously changing the ratio of manganese dioxide (MnO ₂ ) and lithium hydroxide (LiOH). Also,
As the lithium-containing raw material, not only lithium hydroxide but also organic lithium can be used. In the course of the reaction, the lithium hydroxide and the organic lithium form water (H
₂ O). This water is particularly preferable because the polymer gels the polymer, so that the polymer easily adheres to the positive electrode active material.

As the electrolytic solution, not only the above-mentioned ones but also any organic electrolytic solution usually used as an electrolytic solution for a lithium secondary battery can be used.

The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[0064]

According to the present invention, a highly reliable battery can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a lithium secondary battery according to Embodiment 1 of the present invention.

FIG. 2 is an enlarged sectional view showing a portion surrounded by a dotted line II in FIG.

FIG. 3 is a graph showing a relationship between a volume of a polymer with respect to a total volume of a positive electrode active material, a polymer, and a conductive material and a change in capacity of a battery after a charge / discharge cycle.

FIG. 4 is a graph showing a relationship between a ratio of a volume of a polymer to a total volume of a positive electrode active material, a polymer, and a conductive material and a capacity of a battery.

FIG. 5 is a sectional view of a lithium secondary battery according to Embodiment 2 of the present invention.

FIG. 6 is an enlarged sectional view showing a portion surrounded by a dotted line VI in FIG. 5;

FIG. 7 is a sectional view of a lithium secondary battery according to a third embodiment of the present invention.

FIG. 8 is an enlarged sectional view showing a part surrounded by a dotted line VIII in FIG. 7;

FIG. 9 is a sectional view of a lithium secondary battery according to Embodiment 4 of the present invention.

FIG. 10 is a sectional view of a lithium secondary battery according to a fifth embodiment of the present invention.

FIG. 11 is a cross-sectional view of a conventional lithium secondary battery.

[Explanation of symbols]

2 positive electrode current collector, 7 positive electrode active material layer, 7a positive electrode active material, 7b polymer, 7c conductive material, 7d ceramic particles, 7e binder, 8 separator, 10a to 10e
Lithium secondary battery, 17 positive electrode surface layer, 27 polymer layer.

Continued on front page F-term (reference) 5H029 AJ01 AK03 AL12 AM03 AM04 AM05 AM07 AM16 BJ02 BJ12 CJ23 DJ07 DJ08 DJ12 DJ16 EJ04 EJ05 EJ08 EJ12 HJ07 5H050 AA01 AA19 BA16 CA07 CA08 CA09 CB12 DA09 DA10 DA11 FA12 EA08 EA08 EA08 GA23 HA07

Claims (5)

[Claims] 1. A battery formed by sequentially laminating a positive electrode current collector layer, a positive electrode active material layer, an insulating layer, a negative electrode active material layer, and a negative electrode current collector layer, The material layer includes a positive electrode active material containing a lithium metal oxide, a polymer, and a conductive material, and a ratio of the volume of the polymer to the total volume of the positive electrode active material, the polymer, and the conductive material is 50%. More than 80%
The following is a battery. 2. The battery according to claim 1, further comprising an electrolyte surrounding the positive electrode current collector layer, wherein the polymer includes a portion that dissolves in the electrolyte. 3. The battery according to claim 1, wherein the positive electrode active material layer further contains a ceramic powder. 4. The battery according to claim 1, wherein the positive electrode active material layer includes a binder for bonding the conductive material and the polymer. 5. The positive electrode active material according to claim 1, wherein a volume ratio of the polymer to the positive electrode active material is relatively large on the insulating layer side and relatively small on the positive electrode current collector layer side. The battery according to the item.