JPH11102674A - Thin secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily release its gas outside, and prevent a burst when internal pressure increases since gas is generated at overcharge time by arranging a slit part in a resin film part which has rigidity of an enclosing material opposed to a hole arranged in a thermally fusible resin film of an enclosing material inside surface and is put in a nonadhesive condition to metallic foil. SOLUTION: A power generation element 5 is sealed by seal parts 6a, 6b and 6c by mutually and thermally fusing a thermally fusible resin film of its inside surface on the three side edges of an enclosing material 4. The power generation element 5 is layered in order of a positive electrode connected to an external positive electrode lead 13, a polymer electrolyte layer being a separator and a negative electrode connected to an external negative electrode lead 17. A cross-shaped slit part 19 is arranged in a resin film part which has rigidity of the enclosing material 4 opposed to a circular hole 18 arranged in the thermally fusible resin film of the inside surface of the enclosing material 4 and is put in a nonadhesive condition to metallic foil. Therefore, when internal pressure increases since gas is generated, a burst is prevented by realeasing its gas outside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thin secondary battery, and more particularly, to a thin secondary battery provided with a gas release mechanism.

[0002]

2. Description of the Related Art In recent years, a thin secondary battery having a thickness of about 0.5 mm, such as a polymer lithium ion secondary battery, has attracted attention as a power source for cordless devices such as portable personal computers, which emphasize small size and light weight. It is being actively developed.

[0003] Important element technologies for putting the thin secondary battery into practical use include selection of active materials for a positive electrode and a negative electrode, a technology for constructing a battery, and a technology for sealing a thin power generation element pond with an exterior material. Can be When the sealing property of the thin power generating element by the exterior material is reduced, not only does the electrolyte constituting the power generating element volatilize and leak to reduce the battery reaction, but also moisture easily enters from the outside to reduce the performance. Invite.

[0004] For this reason, the conventional thin secondary battery includes a thin power generating element having a positive electrode, a separator, and a negative electrode in an exterior material having a heat-fusible resin film disposed on an inner surface thereof. The external power source connected to the current collector is housed so as to extend from an opening edge of the exterior material, and the heat-fusible resin films are heat-sealed to each other at the opening edge, thereby forming the power generation element. Is sealed in the exterior material. The exterior material is, for example, a laminated film in which a heat-fusible resin film, a barrier film such as an aluminum foil, and a rigid resin film such as a polyethylene terephthalate film are laminated at least in this order.

However, when gas is generated inside the thin secondary battery due to overcharging or the like, the internal pressure increases. For this reason, the laminated film as the exterior material expands and eventually bursts. When a thin secondary battery ruptures, its contents (especially electrolyte) are scattered, and if it is directly mounted on the device, the device will be damaged, and if it is a battery pack, the case will be damaged. Cause damage.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to prevent a gas from being easily escaping to the outside when a gas is generated and its internal pressure rises during overcharging or the like, thereby preventing the gas from bursting. It is an object of the present invention to provide a thin secondary battery capable of performing the following.

[0007]

SUMMARY OF THE INVENTION A thin secondary battery according to the present invention is an exterior material comprising a laminated film in which a heat-fusible resin film, a metal foil, and a rigid resin film are laminated in this order from the inner surface side. In the positive electrode, a separator and a thin-type power generating element having a negative electrode are housed such that external terminals electrically connected to the positive and negative electrodes respectively extend from an opening edge of the exterior material, and at the opening edge. In a thin secondary battery in which the heat-fusible resin films on the inner surface of the outer material are heat-sealed to each other and the power generation element is sealed in the outer material, a part of the heat-fusible resin film on the inner surface of the outer material And a resin film portion having rigidity of the exterior material facing the hole was made to be in a non-adhered state with respect to the metal foil, and a cut portion was provided in the resin film portion in the non-adhered state. That It is an butterfly.

[0008] Another thin secondary battery according to the present invention has a positive electrode, a positive electrode, a heat-fusible resin film, a metal foil and a rigid resin film laminated in this order from the inner surface side. A thin-type power generating element having a separator and a negative electrode is housed such that external terminals electrically connected to the positive and negative electrodes respectively extend from an opening edge of the exterior material, and the interior surface of the exterior material at the opening edge. In a thin secondary battery in which the heat-fusible resin films are heat-sealed to each other and the power generation element is sealed in the exterior material, one of the heat-fusible resin film and the rigid resin film of the exterior material The holes are opened at least in the portions so as to face each other.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a thin secondary battery according to the present invention, for example, a thin polymer electrolyte secondary battery will be described in detail with reference to the drawings. 1 is a perspective view showing a thin polymer electrolyte secondary battery according to the present invention, FIG. 2 is an exploded perspective view of the secondary battery shown in FIG. 1, FIG. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 4 is a sectional view taken along line IV-IV in FIG.

As shown in FIG. 3, an exterior material 4 composed of a laminated film in which a heat-fusible resin film 1, a metal foil 2, and a rigid resin film 3 are laminated in this order from the inner surface side.
A thin power generating element 5 is housed therein, and the heat generating resin film 1 on the inner surface is heat-sealed to each other at, for example, three sides of the exterior material 4 by the sealing portions 6a, 6b, 6c. 5 is sealed. The power generating element 5 has a structure in which a positive electrode 7, a polymer electrolyte layer 8 as a separator, and a negative electrode 9 are laminated in this order.

The positive electrode 7 is made of a current collector 1 made of aluminum.
0 has a structure in which the positive electrode layer 11 is supported on both surfaces. The current collector 10 has a terminal portion 12 made of strip-shaped aluminum foil.
An external positive electrode lead 13 made of aluminum is connected to the terminal portion 12 by ultrasonic welding. The external lead 13 extends outside from the sealing portion 6b of the exterior material 4.

The negative electrode 9 has a structure in which a negative electrode layer 15 is supported on both surfaces of a current collector 14 made of copper. The current collector 14
Has a terminal portion 16 made of a strip-shaped copper foil.
6 is connected to an external negative electrode lead 17 by ultrasonic welding or the like. The external lead 17 extends outside from the sealing portion 6b of the exterior material 4.

A hole, for example, a circular hole 18 is provided in the heat-fusible resin film 1 on the inner surface of the exterior material 4 corresponding to the surface of the power generating element 5 as shown in FIGS. The rigid resin film 3 portion of the exterior material 4 facing the circular hole 18 is in a non-adhered state with the metal foil 2,
In addition, a cut portion, for example, a cross-shaped cut portion 19 is provided in the resin film portion 3 in an unbonded state.

Such a thin polymer electrolyte secondary battery is manufactured, for example, by the following method. First, a circular hole 18 is punched in a predetermined portion of the heat-fusible resin film, and a metal foil is heat-sealed to the resin film. Subsequently, after a cut portion, for example, a cross-shaped cut portion 19 is formed by a cross-shaped punch or the like in a portion corresponding to the circular hole of the rigid resin film, the cut portion of the resin film is formed in the metal foil. Dry lamination is performed so as to be in a non-adhered state, thereby producing, for example, a band-shaped laminated film 20 having a three-layer structure. Subsequently, the thin film power generating element 5 to which the external terminals 13 and 17 of the positive and negative electrodes are attached is connected to the laminated film 20 in which the circular hole 18 is not opened with respect to a bending line 21 located at a central portion parallel to the short side. After the external terminals 13 and 17 are mounted on the portion so as to extend from the end face of the short side of the laminated film 20,
Is bent so as to wrap the power generating element 5 at the bending line 21. Then, the power generating element 5 is sealed by heat-sealing the three sides except for the bent portion, as shown in FIG.
Is manufactured.

The package 4, the positive electrode 7, the negative electrode 9 and the electrolyte layer 8 have the following configuration. 1) Exterior material 4 The exterior material 4 is a heat-fusible resin film 1 from the inner surface side.
It is composed of a laminated film in which a metal foil 2 and a rigid resin film 3 are laminated in this order. Examples of the heat-fusible resin include polyethylene (PE), ionomer,
Ethylene vinyl acetate (EVA) or the like can be used. As the metal foil, for example, an Al foil, a Ni foil, or the like can be used, but an Al foil that can be thinned is preferable. As the rigid resin, for example, polyethylene terephthalate (PET), nylon or the like can be used. However, the rigid resin film may be a combination of two or more films.

As a specific laminated film, a laminated film of PE / Al foil / PET laminated from the sealing surface side to the outer surface; a laminated film of PE / Al foil / nylon;
Laminated film of ionomer / Al foil / PET; Laminated film of ionomer / Al foil / Nylon; Laminated film of ionomer / Ni foil / PET; EVA / Al foil /
A PET laminated film or the like can be used.

The exterior material is formed by bending the laminated film so that the heat-fusible resin film is located on the inner surface (sealing surface), and heat-sealing the end parallel to the bending line to produce a cylindrical material. An external terminal electrically connected to the positive electrode of the thin power generating element extends from one opening, and an external terminal electrically connected to the negative electrode extends from the other opening. And the power generating element may be sealed by heat sealing the two openings.

2) Positive Electrode 7 The positive electrode 7 has a structure in which a positive electrode layer 11 containing an active material, a non-aqueous electrolyte and a polymer holding the electrolyte is supported on both surfaces of a current collector 10 made of aluminum.

As the active material, various oxides (for example, lithium manganese composite oxide such as LiMn ₂ O ₄ ,
Manganese dioxide, for example, a lithium-containing nickel oxide such as LiNiO ₂ , for example, a lithium-containing cobalt oxide such as LiCoO ₂ , a lithium-containing nickel cobalt oxide, and an amorphous vanadium pentoxide containing lithium.
And chalcogen compounds (for example, titanium disulfide, molybdenum disulfide, and the like). Among them, it is preferable to use a lithium manganese composite oxide, a lithium-containing cobalt oxide, and a lithium-containing nickel oxide.

The non-aqueous electrolyte is prepared by dissolving an electrolyte in a non-aqueous solvent. As the non-aqueous solvent,
Ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DE
C), ethyl methyl carbonate (EMC), γ-butyrolactone (γ-BL), sulfolane, acetonitrile, 1,2-dimethoxyethane, 1,3-dimethoxypropane, dimethyl ether, tetrahydrofuran (TH
F) and 2-methyltetrahydrofuran. The non-aqueous solvents may be used alone or as a mixture of two or more.

Examples of the electrolyte include lithium perchlorate (LiClO ₄ ) and lithium hexafluorophosphate (Li
PF ₆ ), lithium borotetrafluoride (LiBF ₄ ), lithium arsenic hexafluoride (LiAsF ₆ ), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ), lithium bistrifluoromethylsulfonylimide [LiN (C
F ₃ SO ₃ ) ₂ ].

The amount of the electrolyte dissolved in the non-aqueous solvent is desirably 0.2 mol / L to 2 mol / L. Examples of the polymer holding the nonaqueous electrolyte include a polyethylene oxide derivative, a polypropylene oxide derivative, a polymer containing the derivative, and a copolymer of vinylidene fluoride (VdF) and hexafluoropropylene (HFP). Can be. The copolymerization ratio of the HFP depends on the method of synthesizing the copolymer, but is usually at most about 20% by weight.

The positive electrode layer may include a conductive material from the viewpoint of improving conductivity. Examples of the conductive material include artificial graphite, carbon black (eg, acetylene black), nickel powder, and the like.

As the current collector, for example, expanded metal made of aluminum, mesh made of aluminum, punched metal made of aluminum, or the like can be used. The positive electrode may have a structure in which a positive electrode layer is supported on one surface of a current collector.

3) Negative Electrode 9 The negative electrode 9 has a structure in which a negative electrode layer 15 containing an active material, a non-aqueous electrolyte and a polymer holding the electrolyte is supported on both surfaces of a current collector 14 made of copper.

Examples of the active material include carbonaceous materials that occlude and release lithium ions. Such carbonaceous materials include, for example, those obtained by firing organic polymer compounds (eg, phenolic resin, polyacrylonitrile, cellulose, etc.), those obtained by firing coke and mesophase pitch, and those made by artificial graphite. And carbonaceous materials represented by natural graphite and the like. Among them, 500
It is preferable to use a carbonaceous material obtained by calcining the mesophase pitch at a temperature of from ℃ to 3,000 ℃ under normal pressure or reduced pressure.

As the non-aqueous electrolyte and the polymer, the same ones as described for the positive electrode described above are used. The negative electrode layer is allowed to contain conductive materials such as artificial graphite, natural graphite, carbon black, acetylene black, Ketjen black, nickel powder, and polyphenylene derivatives, and fillers such as olefin polymers and carbon fibers.

As the current collector, for example, a copper expanded metal, a copper mesh, a copper punched metal, or the like can be used. The negative electrode may have a structure in which a positive electrode layer is supported on one surface of a current collector.

4) Polymer Electrolyte Layer 8 This electrolyte layer 8 contains a non-aqueous electrolyte and a polymer holding the electrolyte. As the non-aqueous electrolyte and the polymer, the same ones as described for the positive electrode described above are used.

The electrolyte layer may contain an inorganic filler such as SiO ₂ powder for improving the compressive strength. The power generating element is not limited to one layer, and two or more layers may be housed in the exterior material.

The hole opened in the heat-fusible resin film of the exterior material is not limited to a circle, but may be any shape such as a square or a polygon. The cut portion provided in the rigid resin film of the exterior material is not limited to the cross shape, but may be a linear shape.

Next, another thin secondary battery according to the present invention,
For example, a thin polymer electrolyte secondary battery will be described with reference to FIGS. FIG. 5 is a perspective view showing another thin polymer electrolyte secondary battery according to the present invention, and FIG. 6 is a sectional view taken along line VI-VI of FIG. In addition, the same members as those in FIGS.

In this thin polymer electrolyte secondary battery, holes (for example, circular holes) are formed in a part of the heat-fusible resin film 1 and the rigid resin film 3 of the exterior member 4 located on the surface of the thin power generating element 5. ) 22 and 23 are open to face each other. That is, the metal foil 2 constituting the exterior material 4 is exposed from the inner surface side and the outer surface side at the locations of the circular holes 22 and 23.

The hole is not limited to a circle, but may be a rectangle, a polygon, or the like. The holes (for example, circular holes) opened in a part of the heat-fusible resin film and the rigid resin film do not necessarily have to have the same dimensions. For example, the holes are opened in the heat-fusible resin film. The round hole formed may be larger than the circular hole opened in the rigid resin film.

In order to increase the volume energy density of the thin type secondary battery, the external terminals 13 and 17 of FIG. 1 or FIG. 5 are bent toward the surfaces of the parallel seal portions 6a and 6c except for the seal portion 6b extending therefrom. May be fixed.

According to the present invention shown in FIGS. 1 to 4 described above, a circular hole 18 is opened in the heat-fusible resin film 1 on the inner surface of the exterior material 4 in which the power generating element 5 is stored.
The resin film 3 having rigidity of the exterior material 4 facing the metal foil 8 is not bonded to the metal foil 2, and a cross-shaped cut 19 is provided in the resin film 3 in the non-bonded state. Accordingly, even if gas is generated from the power generating element 5 due to overcharging or the like and the internal pressure rises, the gas is broken at the location of the metal foil 2 of the exterior material 4 where the circular hole 18 and the cross-shaped notch 19 are located. The gas can escape before the exterior material 4 itself bursts.

That is, as shown in FIG. 7, when gas is generated inside the exterior material 4 and the exterior material 4 expands, the exterior material exposed from the circular hole 18 of the heat-fusible resin film 1 of the exterior material 4 is formed. The metal foil 2 of the material 4 is bent outward, and the unbonded rigid resin film 3 portion located in the metal foil 2 facing the circular hole 18 is opened outward along the cut portion 19. , A hole is formed. As a result, a force is applied to the metal foil 2 to bend outward toward the hole, so that the metal foil 2 is finally broken without being able to withstand the force.

Therefore, when a gas is generated at the time of overcharging and the internal pressure rises, the gas is easily escaping to the outside due to the breakage of the metal foil constituting the exterior material, and the exterior material is ruptured. Can be prevented beforehand. For this reason, it is possible to provide a thin secondary battery capable of avoiding scattering of contents (especially, an electrolytic solution) due to the rupture of the exterior material, and preventing damage to the device when directly mounted on the device.

On the other hand, according to the present invention shown in FIGS. 5 and 6, a circular hole is formed in a part of the heat-fusible resin film 1 and the rigid resin film 3 of the exterior material 4 in which the thin power generating element 5 is housed. When the exterior material 4 expands by generating gas due to overcharging or the like by opening the openings 22 and 23 at least so as to face each other, the above-mentioned portions exposed from the inner surface side and the outer surface side at the circular holes 22 and 23 are provided. Metal foil 2 of exterior material 4
Is subjected to a force curving outward toward the outer recording hole 23, and is finally broken without being able to withstand the force. As a result, when the gas is generated and the internal pressure rises, the gas is easily escaping to the outside due to the breakage of the metal foil constituting the exterior material, thereby preventing the exterior material from being ruptured. it can. Therefore, it is possible to provide a thin secondary battery capable of avoiding scattering of contents (especially, electrolyte solution) due to the rupture of the exterior material and preventing damage to the device when the battery is directly mounted on the device.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. (Example 1) <Preparation of positive electrode> A copolymer of vinylidene fluoride-hexafluoropropylene (VdF-HFP) in acetone (trade name, manufactured by Elphatochem Co., Ltd .; KYNAR2801, copolymerization ratio [VdF: HFP] is 88:12) After dissolving the powder, the acetone solution was mixed with dibutyl phthalate (DB).
P) and a lithium-containing cobalt oxide (manufactured by Nippon Heavy Industries, Ltd.) having a composition formula of LiCoO ₂ as an active material were added to prepare a positive electrode paste. Subsequently, a positive electrode paste having the above composition was applied to a porous current collector made of an aluminum mesh using a knife coater, and dried with dry air, so that a positive electrode not impregnated with electrolyte on both surfaces of the porous current collector was applied. A positive electrode material on which a layer was formed was produced.

<Preparation of Negative Electrode> A vinylidene fluoride-hexafluoropropylene copolymer similar to that used for the positive electrode was dissolved in acetone to prepare an acetone solution, and dibutyl phthalate (D
After adding BP), a mesophase pitch-based carbon fiber (manufactured by Petka Corporation) was added as an active material and mixed to prepare a paste for a negative electrode. This negative electrode paste was applied to a porous current collector made of a copper mesh using a knife coater, and dried with dry air to form a negative electrode having an electrolyte-impregnated negative electrode layer formed on both surfaces of the porous current collector. The material was made.

<Preparation of Solid Polymer Electrolyte Layer> A copolymer of vinylidene fluoride-hexafluoropropylene similar to that used for the positive electrode was dissolved in acetone to prepare an acetone solution. After adding dibutyl phthalate (DBP), the mixture was mixed to prepare an electrolyte layer paste. After applying the paste on a smooth glass plate, dried in the same manner as the positive and negative electrodes,
By peeling off the glass plate, a solid polymer electrolyte material not impregnated with an electrolyte was prepared.

<Preparation of Nonaqueous Electrolyte> A nonaqueous solvent in which ethylene carbonate (EC) and dimethyl carbonate (DMC) were mixed at a volume ratio of 1: 1 was mixed with LiPF ₆ as an electrolyte at a concentration of 1 mol / mol. 1 to prepare a non-aqueous electrolyte.

The obtained positive electrode material, solid polymer electrolyte material and negative electrode material were stacked in this order,
And laminated by heating and pressing with a rigid roll heated to a thickness of 1.0 mm and an outer dimension of 40 mm × 60 mm. Subsequently, the laminate was immersed in methanol to elute DBP in the positive electrode material, the negative electrode material, and the polymer electrolyte material, and these members were used as a porous electrolyte-unimpregnated power generating element having a porous structure. Continued,
External terminals were respectively connected to the strip-shaped terminal portions of the positive and negative porous current collectors of the power generating element by ultrasonic welding or the like.

Next, a thickness of 50 μm and an outer dimension of 70 mm
An outer diameter of 6 is set at a point 35 mm inside the long side of the band-shaped ionomer resin film of 153 mm and 43 mm inside the short side.
An aluminum foil having a thickness of 10 μm was heat-sealed to this resin film. Then, thickness 12
After forming a cross-shaped notch of 5 mm in length and width with a cross-shaped punch at a position corresponding to the circular hole of a PET film of μm, the resin film is so bonded to the Al foil that the position of the cut is not bonded. Dry lamination was performed to produce a three-layer strip-shaped laminated film. Continued,
After placing the electrolyte-impregnated impregnated power generating element to which the external terminals of the positive and negative electrodes are attached so that the external terminals extend from the short side of the laminated film, the laminated film is parallel to the short side at the center. It was folded so as to enclose the electrolyte-unimpregnated power generating element. Continued, width 10mm excluding the bent part
Were heat sealed on three sides. However, a part of one of the two sides excluding the side from which the external terminal extends was left as an unsealed portion. Thereafter, the non-aqueous electrolytic solution is injected into the interior through the unsealed portion, and the unsealed portion is again heat-sealed to form the thin power generating element 5 in the exterior material 4 made of the laminated film shown in FIG. Is sealed and housed, and the exterior material 4 corresponding to the surface of the power generation element 5 is provided.
A circular hole 18 is formed in the ionomer resin film 1 and a cross-shaped notch 19 is formed in the PET film 3 of the exterior material 4 facing the circular hole 18. The thickness is 1.2 mm. 75mm, electric capacity 1
100 thin polymer electrolyte secondary batteries of 00 mAh were manufactured.

(Embodiment 2) Instead of the cut portion, the outer diameter 5
The same configuration as in Example 1 except that a circular hole having a thickness of 10 mm was opened in the PET film of the exterior material.
Zero thin polymer electrolyte secondary batteries were manufactured.

Comparative Example 1 100 thin polymer electrolyte secondary batteries having the same dimensions and electric capacity as in Example 1 except that a circular hole was not formed in the ionomer resin film of the laminated film and a cut portion was not formed in the PET film. Was manufactured.

The obtained secondary batteries of Examples 1 and 2 and Comparative Example 1 were prepared using an internal space of 72 mm × 77 mm × 4.0 m.
Each battery was housed in a polypropylene case having external connection terminals of 75 mm × 80 mm × 6.0 mm and external dimensions of 75 mm × 80 mm × 6.0 mm such that the external terminals of the positive and negative electrodes of each battery were connected to the external connection terminals to assemble a pack-type battery.

An overcharge test was performed on each of the pack-type batteries under the conditions of 1 C and 3 hours, and the amount of deformation of the battery pack case in the thickness direction was measured. The results are shown in Table 1 below. Table 1 Case deformation number Average deformation amount of deformed case Example 10-Example 20-Comparative example 1 100 2.4 mm As is clear from Table 1, the thin secondary batteries of Examples 1 and 2 are packed. When the batteries were used, no deformation of the case was observed. On the other hand, when the thin secondary battery of Comparative Example 1 was a pack-type battery, deformation was observed in 100 out of 100 batteries. When the pack-type batteries of Examples 1 and 2 were disassembled and the thin polymer electrolyte secondary batteries inside the case were examined, all the secondary batteries had circular holes opened in the ionomer resin film constituting the exterior material. A exposed from
It was found that the film had been broken at the point of 1 foil.

[0050]

As described in detail above, according to the present invention, when gas is generated at the time of overcharging and the internal pressure rises,
It is possible to provide a highly safe thin secondary battery capable of easily escaping the gas to the outside and preventing the gas from exploding.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a thin polymer electrolyte secondary battery according to the present invention.

FIG. 2 is an exploded perspective view of the secondary battery of FIG.

FIG. 3 is a sectional view taken along the line III-III in FIG. 1;

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 1;

FIG. 5 is a perspective view showing another thin polymer electrolyte secondary battery according to the present invention.

FIG. 6 is a sectional view taken along the line VI-VI of FIG. 5;

FIG. 7 is a partial cross-sectional view for explaining the operation of the thin polymer electrolyte secondary battery according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Heat-fusible resin film, 2 ... Metal foil, 3 ... Rigid resin film, 4 ... Exterior material, 5 ... Thin power generation element, 7 ... Positive electrode, 8 ... Polymer electrolyte layer, 9 ... Negative electrode, 13, 17: external terminal, 18, 22, 23: circular hole, 19: notch.

Claims (2)

[Claims] 1. A thin power generating element having a positive electrode, a separator, and a negative electrode in an exterior material formed of a laminated film in which a heat-fusible resin film, a metal foil, and a rigid resin film are laminated in this order from the inner surface side. External terminals electrically connected to the positive and negative electrodes, respectively, are housed so as to extend from the opening edge of the exterior material, and the heat-fusible resin films on the inner surface of the exterior material are thermally fused to each other at the opening edge. A thin secondary battery in which the power generation element is attached and sealed in the exterior material, wherein the exterior material has a hole in a part of the heat-fusible resin film on the inner surface of the exterior material, and faces the hole. A thin secondary battery characterized in that a resin film portion having the rigidity described above is not bonded to the metal foil, and a cut portion is provided in the resin film portion in the non-bonded state. 2. A thin power generating element having a positive electrode, a separator, and a negative electrode in an exterior material made of a laminated film in which a heat-fusible resin film, a metal foil, and a rigid resin film are laminated in this order from the inner surface side. External terminals electrically connected to the positive and negative electrodes, respectively, are housed so as to extend from the opening edge of the exterior material, and the heat-fusible resin films on the inner surface of the exterior material are thermally fused to each other at the opening edge. In the thin secondary battery in which the power generation element is attached and sealed in the exterior material, the heat-fusible resin film of the exterior material and a part of the rigid resin film have openings that are at least opposed to each other. A thin secondary battery characterized by the following.