JP2002151023A - Flat type battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flat type battery superior in the reliability, packaged by a light-weighted and thin-walled battery sheath body wherein a short circuit between a reed terminal and the sheath body in an electrode terminal seal part can be reduced. SOLUTION: In the flat type battery in which an electrode laminated body is housed in the sheath body consisting of a laminated film composed of a metallic foil and a heat-fusible resin layer, an insulating resin layer composed of 4-methyl-1-pentene based resin as the main component is installed between a reed terminal and the metallic foil of the sheath body laminated film of the seal part to heat seal the reed terminal, and a short circuit is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery used as a power source for electronic equipment, and more particularly, to a laminated film material in which a positive electrode, a negative electrode, an ion transfer medium, and the like are formed by laminating a metal foil and a resin film. The present invention relates to a flat battery having a structure in which a lead terminal of a positive electrode and a lead terminal of a negative electrode are taken out to the outside.

[0002]

2. Description of the Related Art Recent advances in downsizing, lightening, and thinning of electronic devices have been remarkable, and the batteries used as power sources for mobile phones, personal computers, electronic notebooks, electronic still cameras, and the like have also become lighter. However, the need for thinning is increasing. In response to these demands, conventional batteries have a power generation element sealed in a cylindrical, square, or button-shaped container made by pressing a metal plate such as iron, creating a lightweight and thin battery. Not suitable for For this reason, a flat battery using a laminated film of a metal foil such as an aluminum foil and a resin film as an outer package instead of a metal can has been developed.

[0003] In this flat type battery, the sealing method uses a heat seal using a polymer material instead of the conventional battery caulking, laser welding, or hermetic seal. The feature is that the thickness can be reduced. The flat battery using the polymer laminated film for such an outer package has a structure in which metal lead terminals connected to the positive and negative electrode current collectors are respectively taken out of the bag-shaped outer package. In addition, heat sealing is performed while being sandwiched between the heat-fusible resin layers inside the exterior body.

Conventionally, however, there has been a problem that in the process of heat sealing of the package at the lead terminal take-out portion, the metal foil of the package laminated film and the metal lead terminal come into contact with each other, resulting in a short circuit. Some proposals have been made so far to avoid this short circuit, for example, Japanese Patent Application Laid-Open No. 61-8 / 1986.
In Japanese Patent No. 2662, an insulating inorganic film is vapor-deposited in place of the outer metal foil, or another barrier resin layer (Japanese Patent Application Laid-Open Nos. 6-124692 and 9-77).
No. 884) has been proposed. However, none of them has a sufficient steam barrier property, so that there is a problem that the battery performance decreases with time.

Japanese Patent Application Laid-Open No. 9-265974 discloses that
It is disclosed that an ethylene vinyl alcohol resin layer is provided on a lead terminal portion as an insulating layer that does not melt at the heat sealing temperature of the exterior body. However, since the melting point of ethylene vinyl alcohol resin is not so high, it is necessary to set the sealing temperature low so as not to melt it.Select a material with relatively low heat resistance as the heat-fusible resin layer of the exterior body. There is an inevitable restriction. In addition, when the degree of saponification of the ethylene vinyl alcohol resin is low, there is a concern that the ethylene vinyl alcohol resin may swell with an electrolytic solution.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and uses a battery package comprising a laminated film of a metal foil and a heat-fusible resin layer. It is an object of the present invention to provide a flat battery having high sealing reliability, which prevents a contact short circuit at the time of heat sealing between an electrode lead terminal and a metal foil of an exterior body and does not peel off a seal under high-temperature storage.

[0007]

Means for Solving the Problems The present inventor studied the above problems in various ways and found that a heat-resistant insulating resin layer between the lead terminal and the outer casing metal foil which did not melt at the sealing temperature was used.
A 4-methyl-1-pentene resin layer mainly composed of 4-methyl-1-pentene resin having a melting point of 5 ° C. is provided, and if necessary, an acid-modified olefin resin layer is provided on the lead terminal side. By providing such a battery, it was found that a battery having high sealing reliability and excellent charge / discharge cycle properties was obtained, and the present invention was completed.

Hereinafter, the present invention will be described in detail. The present invention is directed to a power generation element such as a positive electrode, a negative electrode, an ion transfer medium, and the like, in which a battery outer casing is formed of a laminated film in which a metal foil such as aluminum and a heat-fusible resin layer are overlaid. And hermetically sealed. At that time, each of the lead terminals connected to the positive electrode and the negative electrode current collectors has a structure in which the lead terminals are taken out of the outer package through the space between the innermost heat-fusible resin layers of the outer package. Is hermetically sealed in a state sandwiching it.

The first invention includes an outer package, an ion transfer medium encapsulated in the outer package, a positive electrode including a positive electrode active material layer, and a negative electrode including a negative electrode active material layer. The layer and the negative electrode active material layer constitute an electrode laminate that is stacked so as to face each other with the ion transfer medium layer interposed therebetween, and in a battery housed together with the ion transfer medium inside the outer cover, the outer cover is A laminated film comprising at least a metal foil and a heat-fusible resin layer, the outer peripheral portion is sealed so that the electrode laminate is wrapped and sealed,
The metal lead terminals connected to the positive electrode and the negative electrode are respectively taken out of the exterior body, and the lead terminals are also sealed, and at least the lead terminal sealing portion of the exterior body includes the lead terminal and the exterior body metal foil. And 4-methyl-
A flat type battery in which an insulating resin layer made of 1-pentene resin is provided and heat-sealed.

According to a second aspect of the present invention, an adhesive resin (A) layer is disposed at a portion in contact with a lead terminal at least in a lead terminal sealing portion of an exterior body.
2. The flat battery according to claim 1, comprising a composition of a 4-methyl-1-pentene resin and an acid-modified polyolefin resin. The third invention includes an outer package, an ion transfer medium sealed inside the outer package, a positive electrode including a positive electrode active material layer, and a negative electrode including a negative electrode active material layer. The positive electrode and the negative electrode include a positive electrode active material layer and a negative electrode. In a battery in which the active material layers are stacked so as to face each other with the ion transfer medium layer interposed therebetween, and the battery is housed together with the ion transfer medium inside the outer cover, the outer cover is at least a metal foil. And a heat-fusible resin layer and a laminated film,
The outer periphery of the outer package is sealed so that the electrode laminate is wrapped and sealed, the metal lead terminals connected to the positive electrode and the negative electrode are respectively taken out of the outer package, and the lead terminals are also sealed. The sealing material provided on the peripheral portion of the lead terminal has at least three layers of an adhesive resin (A) layer / insulating resin layer / adhesive resin (B) layer. The insulating resin is made of a composition containing a methyl-1-pentene resin and an acid-modified polyolefin resin, the insulating resin is made of a 4-methyl-1-pentene resin, and the adhesive resin (B) is made of 4-methyl-1 -Penten resin and α
An adhesive resin (A) layer is disposed on the lead terminal side, and an adhesive resin (B) layer is disposed on the heat-fusible resin layer side of the package; And a heat-sealed flat battery.

[0011] The laminated film to be the battery casing is composed of, for example, a heat-fusible resin layer, a barrier layer, and a film to be an outer layer, and the laminating method for laminating them is usually a laminating method. Lamination may be performed by either a dry lamination method or an extrusion lamination method, and a laminating agent used at that time is preferably an electrolyte-resistant one. As the heat-fusible resin layer, an olefin resin is usually used from the viewpoint of resistance to an electrolytic solution, and polyethylene and polypropylene are particularly preferably used.
Examples of the polypropylene system include homo-, copolymer, and acid-modified polypropylene.

As the barrier layer, a metal foil is used, and aluminum or an aluminum alloy is lightweight,
It is preferable because of excellent workability. As the outer layer,
Thickness of biaxially stretched polyester, nylon, etc. 12 to 50
Those having a size of about μm are preferably used. In the present invention,
The insulating resin layer made of 4-methyl-1-pentene resin is provided entirely between the barrier layer and the heat-fusible resin layer of the outer laminate film, or only at the peripheral portion of the seal portion of the lead terminal. Although a method of attaching it is conceivable, any method may be used.

The 4-methyl-1-pentene resin is
(A) 50% by weight or more of a 4-methyl-1-pentene polymer and (b-1) poly-1-butene and / or (b-
2) When one or both of the polypropylenes are composed of a composition having a total amount of 0 to 50% by weight, the sealing temperature of the outer package can be sufficiently increased, so that a better effect can be obtained. When the insulating resin layer is provided only on the periphery of the lead terminal seal portion, as shown in FIG. 4, it is preferable that both ends of the seal portion are extended by about 2 mm in the length direction of the lead terminal. The insulating resin layer may be attached to the lead terminal in advance, or may be attached to the periphery of the lead terminal immediately before sealing the lead terminal and the package, and then heat-sealed. In the case where the adhesive is provided only on the periphery of the lead terminal seal portion, an adhesive resin (A) layer for promoting adhesion between the 4-methyl-1-pentene resin and the lead terminal is provided on both sides of the insulating resin layer; It is preferable to provide an adhesive resin (B) layer for promoting adhesion between the -methyl-1-pentene resin and the heat-fusible resin layer of the package.

In order to take such a structure, a method of arranging a sealing material composed of three layers of an adhesive resin (A) layer / insulating resin layer / adhesive resin (B) layer on the periphery of the lead terminal is known. No. This three-layered sealing material can be prepared by any method such as a laminating method and a co-extrusion method. In this case, it is preferable that the film thickness of the adhesive resin (A) layer is 1/4 or more and 2 times or less of the thickness of the lead terminal. If the thickness is smaller than 1/4, it is difficult to sufficiently seal the peripheral portion of the lead terminal. In particular, if the thickness is larger than 2 times, a large step is formed between a portion having a sealing material and a portion having no sealing material. A problem arises in the sealing performance with the seal.

The adhesive resin (A) layer is made of 4-methyl-1-
It is a mixture of 25 to 95% by weight of a pentene-based polymer and 5 to 75% by weight of an acid-modified polyolefin-based resin. More specifically, the acid-modified polyolefin-based resin is composed of propylene, butene-1, and 4- Methyl-1-
A mixture of an unsaturated carboxylic acid-modified α-olefin polymer selected from the group consisting of pentene and an unsaturated carboxylic acid-modified ethylene / α-olefin copolymer is preferred. The adhesive resin (B) layer is preferably a mixture of 40 to 97.5% by weight of a 4-methyl-1-pentene-based polymer and 2.5 to 60% by weight of a 1-butene-based polymer. The 4-methyl-1-pentene-based polymer referred to here includes a 4-methyl-1-pentene homopolymer, a copolymer containing at least 85 mol% of 4-methyl-1-pentene constituent units, or The modified product can be used.

The sealing temperature of the battery package of the present invention is 140
It is preferable to select from the range of ° C to 240 ° C. More preferably, the temperature is from 160C to 210C. As the sealing method, use direct heating such as heat sealing or impulse sealing, friction heating such as spin welding, external heating such as laser, infrared ray, hot jet, internal heating such as high frequency sealing, ultrasonic sealing, etc. Can be. Which sealing method is used may be determined in consideration of the type and structure of the heat-fusible resin layer constituting the exterior body. Further, the heat-fusible resin layers can be joined and sealed by an adhesive, a pressure-sensitive adhesive or the like.

In the present invention, the battery is a battery in which the electrode laminate is housed in a bag made of an outer package, and is a non-aqueous battery and a non-aqueous organic solvent or a non-solvent battery. Examples of this battery include a lithium battery and a lithium ion battery. As the electrode laminate, a battery can be constituted by various electrode materials as a primary battery and a secondary battery. For example, as an electrode material used in a lithium ion secondary battery, a positive electrode material is lithium cobalt oxide, lithium nickelate, lithium manganate, etc., a negative electrode material is a carbon material such as graphite and coke, lithium metal, lithium alloy and metal. A material that can form an intermetallic compound can be used. Usually, a form in which these electrode materials are powdered and coated with a binder, or a continuous form formed by a method such as sintering, rolling, vapor deposition, or sputtering can be used.

Further, as the ion transfer medium between the electrodes,
The materials described below can be used. Various woven fabrics,
Non-woven, paper, foam sheet, or polyethylene, poly
Polio such as propylene or a combination thereof
Porous resin film represented by refining microporous membrane
It is possible to use a material impregnated with a non-aqueous solvent-based electrolyte
It is possible. Or aluminum oxide, silicon oxide,
Titanium oxide, zirconium oxide, titanium nitride, aluminum nitride
Minium, silicon carbide, zircon, zeolite, etc.
Inorganic particles represented, polyethylene, polypropylene,
Polystyrene, aramid, polyamide resin, polyimide
Organic particles represented by resin, polyacetal resin, etc.
Insulation with three-dimensional mesh void structure composed of
A porous layer consisting of aggregates of material particles,
A layer is formed directly on at least one electrode active material layer surface;
Using a material impregnated with a non-aqueous solvent electrolyte
It is possible to Alternatively, use non-aqueous solvent electrolyte
Material that is impregnated and swelled uniformly or unevenly
For example, polyacrylonitrile, polyethylene oxide
, Polymethyl methacrylate, poly (styrene-acryl
Ronitrile), polyvinyl acetate, polyvinyl chloride, poly
(Vinyl chloride-vinylidene fluoride), polyvinylidene fluoride
Den, poly (vinylidene fluoride-hexafluoropropyl)
Poly (vinylidene fluoride) such as
Molecular weight represented by lonitrile-butadiene rubber, etc.
Large polymer plasticized with non-aqueous electrolyte
Can be used. Alternatively, ion coordination
Ions that can migrate to rimers and / or ceramic materials
Material containing, for example, polyethylene oxide,
Polyethers such as propylene oxide and polyether
Stele, polyimine, polysulfide, polyether frame
Donor type represented by bridges and polyether derivatives
A composite material of a polymer having a polar group and an electrolyte salt, Li
_{3 + x}A_1-xB_xO_Four(A = P, V, As, B = Si, Ge,
Ti), LiM_Two(PO_Four)_Three(M = Zr, Ge, Ti,
Hf), Li_{1 + x}M_xTi_2-x(PO_Four)_Three(M = Al, S
c, Y, La), LiI, LiI.Al_TwoO_Three, Li_ThreeP
O_Four・ Li_TwoS ・ SiS_TwoGlass, Li _TwoS ・ SiS_Twosystem
Glass, Li_xPO_yN_zPhosphorus oxynitride represented by
Inorganic materials, such as rubber, or their composites
Etc. can be used.

As the structure of the electrode laminate, an element structure including a positive electrode / an ion transfer medium / anode and a structure in which the element structures are stacked in series or in parallel can be used. Further, a lead terminal for extracting a current from the electrode is connected to the electrode to form a battery structure. As the shape of the electrode laminated body, a simple laminated shape of a flat electrode, a wound laminated shape of a strip electrode, or the like can be used. As described above, the battery component, structure, and form of the present invention can be selected from various types according to applications and purposes. The structure of the outer package can be designed in accordance with the structure of these electrode laminates, and the electrode laminate is arranged inside the outer package to form a structure in which each of the lead terminals is sealed inside and outside the outer package. It can be.

[0020]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, when an insulating resin layer made of a 4-methyl-1-pentene-based resin is attached to the entire area between the barrier layer and the heat-fusible resin layer of the exterior laminate film to form a battery, The sectional view of the seal part of the positive electrode lead terminal taken out from the exterior body to the outside is shown.

The outer laminate film (X) 5 comprises a stretched nylon film 1 as an outer layer, an aluminum foil 2 as a barrier layer, and a 4-methyl-1-pentene resin film 4 as an insulating resin layer. It consists of four layers with the polypropylene film 3 which is a heat-fusible resin layer. The package laminate film (X) 5 has a bag shape with the polypropylene film 3 inside, and contains an electrode laminate (not shown). An acid-modified polypropylene film 7 is heat-sealed between the lead terminal 8 and the package laminate film (X) 5 for the purpose of increasing the adhesive strength. The lead terminal 8 does not directly contact the polypropylene film 3,
Heat sealing is performed with the acid-modified polypropylene film 7 sandwiched therebetween. As a result, the adhesive strength of the lead terminal portion is strengthened, and it is effective in preventing liquid leakage. The acid-modified polypropylene film 7 exerts an adhesive force by completely covering the lead terminal 8 at least on the sealing surface, and as shown in FIG. Demonstrate.

FIG. 2 is a cross-sectional view of the sealing portion of the positive electrode lead terminal taken out of the outer package when a battery is manufactured by attaching an insulating resin layer only to the peripheral portion of the sealing portion of the lead terminal. Show. Outer body laminated film (Y)
Reference numeral 6 comprises three layers: a stretched nylon film 1 as an outer layer, an aluminum foil 2 as a barrier layer, and a polypropylene film 3 as a heat-fusible resin layer. The package laminate film (Y) 6 has a bag shape with the polypropylene film 3 inside, and contains an electrode laminate (not shown). Heat sealing is performed with the sealing material (P) 12 interposed between the lead terminal 8 and the package laminate film (Y) 6. The sealing material (P) 12 is made of the adhesive resin (B) layer 1
1, an insulating resin layer 10, and an adhesive resin (A) layer 9. The adhesive resin (B) layer 11 and the polypropylene film 3, the adhesive resin (A) layer 9, the lead terminals 8, Are arranged in such a manner that they are in contact with each other. The sealing material (P) 12 exerts an adhesive force by completely covering the lead terminals 8 at least on the sealing surface.
As shown in (1), by arranging it wider than the lead terminals 8, a sufficient effect is exhibited.

<Preparation of Electrode Stack> An electrode and a method of preparing an electrode stack using the electrode will be described. [Positive electrode]
LiCoO ₂ Lithium Cobalt 100 as active material
Parts by weight, 2.5 parts by weight of flaky graphite and acetylene black as conductive agents, and 3.5 parts by weight of polyvinylidene fluoride (PVdF) as a binder, N-
A slurry was prepared by dispersing in methylpyrrolidone (NMP). This slurry is used as a positive electrode current collector with a thickness of 20
Coating both sides of aluminum foil of μm with die coater,
After drying at 130 ° C. for 3 minutes, compression molding was performed with a roll press. At this time, the active material basis weight of the positive electrode was 250 g / m ² ,
The double-sided positive electrode sheet was prepared such that the bulk density of the active material was 3.00 g / cm ³ . Similarly, a single-sided positive electrode sheet in which only one side of an aluminum foil was coated with a die coater was prepared.

[Negative electrode] Mesophase pitch carbon fiber (MCF) 9 graphitized as an active material
A slurry was prepared by dispersing 0 parts by weight, 10 parts by weight of flaky graphite, 1.4 parts by weight of an ammonium salt of carboxymethyl cellulose as a binder, and 1.8 parts by weight of a styrene-butadiene copolymer latex in purified water. This slurry was used as a negative electrode current collector to a thickness of 12 μm.
The both surfaces of the copper foil are coated with a die coater, dried at 120 ° C. for 3 minutes, and then compression-molded by a roll press. At this time, a double-sided negative electrode sheet was prepared such that the basis weight of the active material of the negative electrode was 106 g / m ² and the bulk density of the active material was 1.35 g / cm ³ .

[Electrode Laminated Body] (1) From the obtained positive electrode sheet on both sides and one side, a width of 100 mm and a length of 100 m
m of the electrode plate (10 mm in the length direction is an uncoated portion of the active material layer), and a width of 102 mm,
An electrode plate having a length of 102 mm (10 mm in the length direction, an uncoated portion of the active material layer) was cut out. 110mm in width and 19 in length
A 0 mm polyethylene microporous membrane separator was bent at the center in the length direction, and two sides in the length direction were heat-sealed with a heat sealer (180 ° C.) with a width of 2 mm and a width of 110 m.
m, a separator bag having a rectangular shape with a length of 95 mm and a width direction opened by one side was prepared.

The negative electrode plate is inserted into the bag-shaped separator so that the uncoated portion of the active material is exposed, and the positive electrode active material layer and the negative electrode active material layer face each other with the separator interposed therebetween. The positive electrode active material layers are stacked so as not to protrude from the negative electrode active material layers. At this time, the uppermost layer and the lowermost layer were single-sided positive electrodes (the aluminum foil was on the outside), and between them, six double-sided negative electrodes and five double-sided positive electrodes were alternately stacked to prepare an electrode laminate. Further, the current collectors of the uncoated portion of the negative electrode active material layer of the electrode laminate were put together to form a copper foil strip (width 5 mm, length 30 m).
m, 150 μm in thickness) and ultrasonic welding together with the lead terminal, and similarly collectively collect the current collector in the uncoated portion of the positive electrode active material layer,
Aluminum foil strip (width 5mm, length 30mm, thickness 1
It was ultrasonically welded together with a lead terminal of 50 μm (electrode laminate 1).

(2) An electrode laminate was prepared using another form as an ion transfer medium between the electrodes. First, ethylene carbonate and γ-butyrolactone were mixed at a volume ratio of 1: 2, and lithium tetrafluoroborate was mixed at 1 mol / mol.
Dissolved to a liter. A polyacrylonitrile powder (average molecular weight: 150,000) was added to this solvent so that the polyacrylonitrile became 15 mol%, and 1
The temperature was raised to 00 ° C., and the mixture was heated and stirred for about 30 minutes to form a highly viscous solution. This was allowed to cool to obtain a gel electrolyte. Next, a gel electrolyte is applied to a positive electrode plate and a negative electrode plate of the same size as in the preparation of the electrode laminate (1), and then a plurality of sheets are stacked so as not to be shifted. Created.

Further, the current collector in the uncoated portion of the negative electrode active material layer of the electrode laminate was put together and ultrasonically welded together with a copper foil strip (width 5 mm, length 30 mm, thickness 150 μm) lead terminal. Similarly, the current collectors of the uncoated portion of the positive electrode active material layer are collectively collected into aluminum foil strips (width 5 mm, length 30 mm,
It was ultrasonically welded together with the lead terminal having a thickness of 150 μm (electrode laminate 2).

<Preparation of Sealing Material> Next, a method of preparing a sealing material used when the insulating resin layer is provided only on the peripheral portion of the sealing portion of the lead terminal will be described.

As the adhesive resin (A), 4-methyl-1
A mixture of 50% by weight of a pentene homopolymer, 25% by weight of an unsaturated carboxylic acid-modified propylene polymer, and 25% by weight of an unsaturated carboxylic acid-modified ethylene / propylene copolymer was prepared. Similarly, a mixture of 50% by weight of a 4-methyl-1-pentene homopolymer and 50% by weight of a 1-butene-based polymer was prepared as the adhesive resin (B). In addition, a 4-methyl-1-pentene homopolymer was prepared as an insulating resin, the adhesive resin was 250 ° C., and the insulating resin was 28 ° C.
Adhesive resin (A) layer / insulating resin layer / adhesive resin (B) using a three-layer coextrusion molding machine at a molding temperature of 0 ° C.
A laminated film sealing material having a three-layer structure was prepared.

A laminated film having an adhesive resin (A) layer of 40 μm, an insulating resin layer and an adhesive resin (B) layer of 20 μm each and a total thickness of 80 μm was used as a sealing material (P). The adhesive resin (A) layer and the insulating resin layer each having a thickness of 20 μm, and the adhesive resin (B) layer having a thickness of 40 μm.
m, and a laminated film having a total thickness of 80 μm is defined as a sealing material (Q).

[0032]

Example 1 As an exterior body, a stretched nylon film (film thickness 15 μm), aluminum foil (film thickness 40 μm),
Methyl-1-pentene resin film [manufactured by Mitsui Chemicals, Inc.
Opylan X44B (film thickness 25 μm)] and a polypropylene film (film thickness 20 μm) were sequentially laminated to prepare a laminated film (X) (dry lamination method). A rectangular piece having a width of 120 mm and a length of 240 mm was cut out from the laminated film, and the center in the length direction was bent so that the polypropylene layer was on the inner side, to obtain a width of 120 mm and a length of 12 mm.
A two-layer laminated film piece of 0 mm was prepared. Then, one side in the length direction of the obtained film piece was heat-sealed with a heat sealer (180 ° C.) having a width of 5 mm to prepare an exterior body in which the width and the length direction were opened one by one.

An electrode laminate 1 separately prepared is inserted into the package so that the lead terminal extends outside the side corresponding to the width of the package, and an acid-modified polypropylene film ( 80 μm thick, 10 m wide
m, length of 10 mm) is arranged so that the length direction protrudes about 2 mm from the exterior body, and 5 mm together with the exterior body from above.
Twenty pieces were heat-sealed with a width heat sealer (200 ° C.). First, the insulation resistance between the positive and negative lead terminals was measured. This insulation resistance value is 20MΩ
Only those that passed above were judged to be acceptable and proceeded to the next step.

After injecting 20 g of the electrolytic solution from the remaining unsealed side of the package into which the electrode laminate is inserted, the pressure is reduced and the electrolytic solution is sufficiently impregnated under vacuum, and then carbon dioxide gas is introduced. Then, the insides of the package members were heat-sealed with a heat sealer (180 ° C.) having a width of 5 mm to form a lithium ion secondary battery. As an electrolytic solution, ethylene carbonate and γ-butyrolactone were mixed at a volume ratio of 1: 2, and lithium tetrafluoroborate was mixed at 1 mol / mol.
A solution dissolved to a liter was used.

The battery thus manufactured was evaluated under the following conditions. After measuring the weight of the battery, the battery was placed in an atmosphere of 25 ° C., charged at a current value of 1.7 A to a battery voltage of 4.2 V, and further reduced in current value from 1.7 A to maintain 4.2 V. By the method of starting, the first charge after the battery was manufactured was performed for a total of 6 hours. Then, after being left for 2 weeks in an atmosphere of 25 ° C., the weight of the battery was measured.
After being left for one week in an atmosphere of ° C., the battery weight was measured again. Table 1 shows the evaluation results. All of the 20 samples measured had sufficient inter-terminal insulation resistance, had no problem in charging, no change in weight was measured even after long-term storage, and there was no electrolyte leakage from the seal portion.

[0036]

Example 2 Stretched nylon film (film thickness 15 μm),
A laminated film (Y) in which an aluminum foil (film thickness: 40 μm) and a polypropylene film (film thickness: 20 μm) were sequentially laminated was prepared by a dry lamination method. A rectangular piece having a width of 120 mm and a length of 240 mm was cut out from the laminated film, and the central portion in the length direction was bent so that the polypropylene layer was on the inside, and the width was 120 mm and the length was 120 m.
m was prepared. Then, one side in the length direction of the obtained film piece was heat-sealed with a heat sealer (180 ° C.) having a width of 5 mm to prepare an exterior body in which the width and the length direction were opened one by one.

The separately prepared electrode laminate 1 was inserted into this package so that the lead terminals protruded outside the side corresponding to the width of the package, and the electrode laminate 1 prepared separately was provided in the seal between the lead terminal and the package. Sealing material (P) consisting of a laminated film of adhesive resin (A) layer / insulating resin layer / adhesive resin (B) layer
(Film thickness: 80 μm, width: 10 mm, length: 10 mm), and the length direction is set so that the adhesive resin (A) layer is on the lead terminal side, the adhesive resin (B) layer is on the exterior body side, and the length direction is 2 mm.
It was arranged so as to protrude by about mm from the exterior body, and heat-sealed with a heat sealer (200 ° C.) having a width of 5 mm together with the exterior body from above. Thereafter, in the same manner as in Example 1, a lithium ion secondary battery was prepared and evaluated. This evaluation result,
The results are shown in Table 1. All of the 20 samples measured had sufficient inter-terminal insulation resistance, had no problem in charging, no change in weight was measured even after long-term storage, and there was no electrolyte leakage from the seal portion.

[0038]

[Example 3] [Electrode laminate] Twenty lithium ion secondary batteries were prepared in the same manner as in Example 2 except that the electrode laminate 2 using the gel electrolyte prepared by the preparation method (2) was used. did. Thereafter, the prepared battery was evaluated in the same manner as in Example 2. Table 1 shows the evaluation results. 20 measured
All of them had sufficient insulation resistance between terminals, had no problem in charging, and no change in weight was measured even after long-term storage.

[0039]

Embodiment 4 Instead of using the sealing material (P) for the sealing portion between the lead terminal and the package, a separately prepared sealing material (Q) is bonded to the lead terminal side with the adhesive resin (A) layer. Twenty lithium ion secondary batteries were produced in the same manner as in Example 2, except that the conductive resin (B) layer was arranged so as to be on the side of the outer package and heat sealed with a heat sealer (180 ° C.). Thereafter, the prepared battery was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results.

[0040]

Comparative Example 1 Instead of using a sealing material (P) composed of a laminated film of an adhesive resin (A) layer / insulating resin layer / adhesive resin (B) layer in a seal portion between a lead terminal and an exterior body,
A lithium ion secondary battery was prepared in the same manner as in Example 2, except that an ionomer resin film (80 μm in thickness) was used. Thereafter, the prepared battery was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results. In Comparative Example 1, only 12 out of the 20 terminals measured had sufficient inter-terminal insulation, and the weight of these 12 terminals also decreased in the high-temperature storage test.

[0041]

Comparative Example 2 Example 2 was repeated except that a 4-methyl-1-pentene resin film (80 μm thick) was used instead of the sealing material (P) for the seal between the lead terminal and the package. In the same manner as in the above, a lithium ion secondary battery was prepared. Thereafter, the prepared battery was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results. In Comparative Example 2, the insulation between the terminals was maintained, but the adhesiveness to the lead terminals was poor and the openings were opened immediately, so that the weight change could not be evaluated.

[0042]

[Comparative Example 3] Instead of using the sealing material (P) for the sealing portion between the lead terminal and the exterior body, a separately prepared sealing material (Q) is bonded to the lead terminal side with the adhesive resin (B) layer. Twenty lithium ion secondary batteries were prepared in the same manner as in Example 2 except that the conductive resin (A) layer was arranged so as to be on the side of the outer package and heat sealed with a heat sealer (180 ° C.). Thereafter, the prepared battery was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results. The battery of Comparative Example 3 obtained sufficient inter-terminal insulation resistance and appeared to adhere to the lead terminals, but the weight was reduced by long-term storage.

[0043]

[Table 1]

[0044]

According to the present invention, in a light-weight and thin-walled battery using a laminated film composed of a metal foil and a heat-fusible resin layer as an outer package, a short circuit between terminals of an electrode lead terminal portion is greatly reduced. In addition, the sealing property is enhanced, and the reliability and stability of the battery can be greatly improved.

[Brief description of the drawings]

FIG. 1 shows an example of a cross section of a positive electrode lead terminal sealing portion before heat sealing in Example 1 of the present invention.

FIG. 2 shows an example of a cross section before heat sealing of a positive electrode lead terminal sealing portion in Example 2 of the present invention.

FIG. 3 is a perspective view of a battery according to a second embodiment of the present invention.

[Description of Signs] 1 Stretched nylon film 2 Aluminum foil 3 Polypropylene film 4 4-Methyl-1-pentene resin film 5 Laminated film (X) 6 Laminated film (Y) 7 Acid-modified polypropylene film 8 Positive electrode lead terminal 9 Adhesion Resin (A) layer 10 Insulating resin layer (4-methyl-1-pentene resin film) 11 Adhesive resin (B) layer 12 Sealing material (P)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H011 AA03 AA17 CC02 CC10 FF04 GG09 HH02 HH13 5H029 AJ12 AJ15 AK03 AL07 AL08 AL12 AM00 AM03 AM04 AM05 AM16 BJ04 DJ02 DJ03 DJ05 EJ11

Claims (3)

[Claims] The present invention includes an outer package, an ion transfer medium enclosed in the outer package, a positive electrode including a positive electrode active material layer, and a negative electrode including a negative electrode active material layer, wherein the positive electrode and the negative electrode include a positive electrode active material layer and a negative electrode active material. In a battery that is configured with an electrode stack that is stacked so that the material layers face each other with the ion transfer medium layer interposed therebetween, and that is housed together with the ion transfer medium inside the exterior body,
The exterior body is a laminated film comprising at least a metal foil and a heat-fusible resin layer, the periphery of the exterior body is sealed so that the electrode laminate is wrapped and sealed, and the metal connected to the positive electrode and the negative electrode The lead terminals are each taken out of the package and the lead terminals are also sealed, and at least the lead terminal seal portion of the package is provided between the metal foil and the heat-fusible resin layer. A flat battery, wherein an insulating resin layer made of a methyl-1-pentene resin is provided and heat-sealed. 2. An adhesive resin (A) layer as a heat-fusible resin layer is disposed on at least the lead terminal sealing portion of the package, and the adhesive resin (A) is made of 4-methyl-1-
The flat battery according to claim 1, comprising a composition containing a pentene-based resin and an acid-modified polyolefin-based resin. 3. An outer package, an ion transport medium enclosed in the outer package, a positive electrode including a positive electrode active material layer, and a negative electrode including a negative electrode active material layer. The positive electrode and the negative electrode include a positive electrode active material layer and a negative electrode active material. In a battery that is configured with an electrode stack that is stacked so that the material layers face each other with the ion transfer medium layer interposed therebetween, and that is housed together with the ion transfer medium inside the exterior body,
The exterior body is a laminated film comprising at least a metal foil and a heat-fusible resin layer, the periphery of the exterior body is sealed so that the electrode laminate is wrapped and sealed, and the metal connected to the positive electrode and the negative electrode Each of the lead terminals is taken out of the exterior body, and the lead terminals are also sealed. The sealing material provided on the periphery of the lead terminals is made of an adhesive resin (A).
Layer / insulating resin layer / adhesive resin (B) layer at least 3
The adhesive resin (A) has a layer structure, and 4-methyl-1
-A composition comprising a pentene-based resin and an acid-modified polyolefin-based resin, wherein the insulating resin comprises a 4-methyl-1-pentene-based resin, and the adhesive resin (B) comprises a 4-methyl-1-pentene-based resin. It consists of a composition containing a resin and an α-olefin-based polymer, and has a surface of an adhesive resin (A) layer on the lead terminal side and an adhesive resin (B) on the heat-fusible resin layer side of the package.
A non-aqueous battery having a layer surface arranged and heat sealed.