JP2002319378A - Packaging material for battery, and battery using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow stable sealing without generating short-circuiting between a barrier layer of an armor body and a lead wire caused by heat and pressure in heat seal, when a battery body is inserted into the armor body using a polypropylene resin as a heat seal layer to seal its peripheral edge by the heat seal, in a battery packaging. SOLUTION: This packaging material for forming the armor body for a battery for inserting the battery body to seal its peripheral edge part by the heat seal consists of a packaging material for the battery comprising a layered body constituted of at least a base material layer 11, aluminum 12, a formation- treated layer, an adhesive layer 13, and a sealant layer 14, wherein at least the innermost layer of the sealant layer is an acid-modified polyolefin, and in which a polyolefin layer cross-linked to be brought into at least 0.5%-80% of gel fraction is contained between the acid-modified polyolefin and the aluminum.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a battery packaging material comprising:
Used in batteries with a liquid or solid organic electrolyte (polymer polymer electrolyte) having moisture resistance and content resistance, or in fuel cells, capacitors, capacitors, etc., short-circuits between the barrier layer of the outer package and the lead wires. TECHNICAL FIELD The present invention relates to an exterior body that wraps a battery main body that does not occur and a battery using the same.

[0002]

2. Description of the Related Art A battery in the present invention includes a device including a device for converting chemical energy into electrical energy, for example, a lithium ion battery, a lithium polymer battery, a fuel cell, or the like, or a liquid, solid ceramic, or organic material. 1 shows an electrolytic capacitor such as a liquid capacitor, a solid capacitor, and a double-layer capacitor including a dielectric such as Battery applications include personal computers, mobile terminal devices (mobile phones, PDAs
Etc.), video cameras, electric vehicles, storage batteries for energy storage, robots, satellites, etc. As the outer package of the battery, a metal can formed by pressing a metal into a cylindrical or rectangular parallelepiped container, or a plastic film, a laminate of a composite film obtained by laminating a metal foil or the like into a bag shape. (Hereinafter, an exterior body) was used. There were the following problems as a battery exterior. In a metal can, the shape of the battery itself is determined because the outer wall of the container is rigid. Therefore, since the hardware side is designed to match the battery, the size of the hardware using the battery is determined by the battery, and the degree of freedom of the shape is reduced. Therefore, there is a tendency to use the bag-shaped exterior body. The material composition of the outer package is composed of at least a base material layer, a barrier layer, a heat seal layer and an adhesive layer for bonding the respective layers, from the necessary physical properties, workability, economy, and the like as a battery, and intermediate if necessary. A layer may be provided. A pouch is formed from the laminated body having the above-described configuration of a battery, or at least one side is press-molded to form a battery storage portion, and a battery body is stored therein, and a pouch type or an embossed type (covering a lid) is formed. , Necessary parts of the respective peripheral edges are sealed by heat sealing to form a battery. As the heat sealing layer, a lead wire (metal) together with the heat sealing property of the heat sealing layers.
Is also required to have heat sealability, and by using an acid-modified polyolefin resin having metal adhesiveness as the heat seal layer, adhesion to the lead wire portion is ensured.

However, when an acid-modified polyolefin resin is laminated as a heat seal layer of an exterior body, its workability is inferior to that of a general polyolefin resin.
Due to the high cost etc., a general polyolefin resin layer is used as the heat seal layer of the exterior body, and a lead wire film that can be thermally bonded to both the heat seal layer and the lead wire is interposed in the lead wire part Was adopted.
Specifically, as shown in FIG. 7A, between the lead wire 4 and the heat seal layer 14 'of the laminate 10', heat seal is performed on both the metal and the heat seal layer of the exterior material. By interposing the lead film 6 'having the property, the sealing performance at the lead wire portion is ensured. As the lead wire film, a film made of the unsaturated carboxy-grafted polyolefin, metal cross-linked polyethylene, or a copolymer of ethylene or propylene with acrylic acid or methacrylic acid can be used.

[0004]

However, in the case where the heat seal layer of the laminate constituting the outer package of the battery (hereinafter referred to as "exterior package") is made of a polyolefin resin, the battery main body is housed in the outer package and the periphery thereof is covered. Seal and seal, for example,
When using a lead film 6 ′ composed of an acid-modified polyolefin single layer, in a portion where a lead wire is present,
As shown in FIG. 7 (b), the heat seal layer 14 'and the lead wire film layer 6' of the outer package are both melted by heat and pressure for heat sealing, May be extruded out of the area. As a result, the aluminum foil, which is the barrier layer 12 'of the exterior body 10', and the lead wire 4 'made of metal may contact (S) and cause a short circuit. An object of the present invention is to provide a battery package, in which a battery body is inserted into a package having a polyolefin-based resin as a heat sealing layer, and the periphery thereof is heat-sealed and sealed. An object of the present invention is to provide a battery packaging material that can stably seal without causing a short between a barrier layer and a lead wire.

[0005]

The above objects can be attained by the present invention described below. That is, claim 1
The invention described in (1) is a packaging material for forming a battery exterior body in which a battery main body is inserted and a peripheral portion is sealed by heat sealing, wherein at least a base material layer, an adhesive layer 1, aluminum,
It is composed of a laminate composed of a chemical conversion treatment layer, an adhesive layer 2, and a multilayer sealant layer. The innermost layer of the multilayer sealant layer is an acid-modified polyolefin, and at least a gel fraction between the acid-modified polyolefin and aluminum is 0. 5% to 80
% Of a packaging material comprising a polyolefin layer that has been cross-linked so as to obtain a polyolefin layer. According to a second aspect of the present invention, the laminate according to the first aspect includes a base material layer, an adhesive layer 1, a chemical conversion layer 1, aluminum, a chemical conversion layer 2, an adhesive layer 2, and a multilayer sealant layer. It is characterized by the following. The invention described in claim 3 is characterized in that the polyolefin described in claim 1 or 2 is polypropylene. The invention described in claim 4 is characterized in that the polyolefin described in claim 1 or 2 is polyethylene. The invention described in claim 5 is the adhesive layer 1 to claim 4
Wherein the adhesive layer 1 and the adhesive layer 2 are formed by a dry lamination method. The invention described in claim 6 is characterized in that the adhesive layer 2 according to any one of claims 1 to 4 is a coating baking layer of an acid-modified polyolefin. The invention described in claim 7 is characterized in that the adhesive layer 2 according to any one of claims 1 to 4 is an extruded layer of an acid-modified polyolefin. According to an eighth aspect of the present invention, an adhesive film is interposed between an outer package of a battery formed from the packaging material according to any one of the first to seventh aspects and a lead wire of the battery body. It is characterized by the following. The invention described in claim 9 is claim 1 to claim 1
A battery is characterized in that the battery body is inserted into the battery outer package made of the battery packaging material according to any one of claims 8 and heat-sealed at the periphery thereof.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The battery packaging material of the present invention comprises at least a substrate layer, an adhesive layer, a chemical conversion layer 1, aluminum,
In a battery outer package composed of a sealant layer in which the chemical conversion treatment layer 2, the adhesive layer and the heat seal layer are acid-modified polyolefin layers, at least a gel fraction of at least 0.5 between the acid-modified polyolefin and aluminum. % ~
What is claimed is: 1. A packaging material comprising a polyolefin layer cross-linked to 80%, wherein the sealant layer containing the cross-linked layer has excellent heat resistance and is cross-linked even when hermetically sealing the exterior body. The sealant layer is made of a material that retains the film shape and does not cause a short circuit due to contact between the aluminum and the metal lead wire. The details will be described below with reference to the drawings and the like.

FIG. 1 is a view for explaining a battery packaging material of the present invention. FIG. 1A is a cross-sectional view showing the positional relationship between a battery packaging material showing a layer structure and a lead wire, and FIG. FIG. 3C is a cross-sectional view illustrating a state where a lead wire and a package before heat sealing are in contact with each other, and FIG. 4C is a schematic cross-sectional view of the lead wire portion after heat sealing. (D), (e), and (f) are the same explanatory diagrams at the time of using the battery packaging material which has another sealant composition. FIG. 2 is a cross-sectional view illustrating an example of a layer configuration of a stacked body that forms an exterior body of a battery.
FIG. 3 is a perspective view illustrating a pouch type exterior body of the battery. FIG. 4 is a perspective view illustrating an embossed type exterior body of the battery. Figure 5 illustrates the molding in embossed type, (a) a perspective view, (b) embossing the molded outer body, (c) X ₂ -X ₂ parts cross-sectional view, with (d) Y ₁ part enlarged view is there. FIG. 6 is a diagram illustrating a method of mounting a lead wire film in bonding a battery packaging material and a lead wire.

[0008] The lead wire of the battery is made of an elongated plate-shaped or rod-shaped metal.
The thickness is about 50 to 2000 μm, the width is about 2.5 to 20 mm, and the material is AL, Cu (including Ni plating), Ni, or the like.

[0009] The battery exterior is required to have the performance of maintaining the performance of the battery body for a long period of time, and a base layer, a barrier layer, a heat seal layer, and the like are laminated by various lamination methods. In particular, when the heat seal layer of the laminate constituting the battery outer package (hereinafter referred to as “package”) is made of a polyolefin-based resin or the like, when the battery main body is housed in the package and the periphery thereof is sealed and sealed, the lead is In the case where an acid-modified polyolefin is used as a film for a lead wire in a portion where a wire exists, for example, as shown in FIG. 7A and FIG. The seal layer and the lead film layer are both melted, and the layer inside the barrier layer 12 ′ of the outer package and the lead film layer 6 ′, both of which have been an insulating layer, are both pressed by pressure. It may be pushed out of the area of the pressing section. As a result, the aluminum foil serving as the barrier layer 12 'of the outer package may come into contact with the lead wire 4' made of a metal, resulting in a short circuit S.

The present inventors have conducted intensive studies on the prevention of the short-circuit S, and as a result, have found that a laminate of battery packaging materials comprises a base material layer and a multilayer sealant layer in which a heat seal layer is an acid-modified polyolefin, By providing a packaging material characterized by including a polyolefin layer cross-linked so that the gel fraction is at least 0.5% to 80% between the acid-modified polyolefin and aluminum of the multilayer sealant, The inventors have found that short-circuit between the barrier layer and the lead wire due to heat and pressure during sealing can be prevented, and have completed the present invention.

As shown in FIG. 2 (a), the battery packaging material of the present invention comprises at least a base material layer 11, an adhesive layer 16, aluminum 12, a chemical conversion layer 15, an adhesive layer 13d, and a multilayer sealant layer 14. In the case where an exterior body described later is an embossed type, as shown in FIG.
6, chemical conversion treatment layer 15 (1), aluminum 12, chemical conversion treatment layer 15 (2), adhesive layer 13d, multilayer sealant layer 14
It is desirable that

The sealant of the battery packaging material according to the present invention is, for example, as shown in FIG.
An acid-modified polyolefin resin S2e is formed on one side of a polyolefin film S1 crosslinked to 5% to 80% by extrusion. When the package material is hermetically sealed, the layer structure before pressurization at the lead wire portion shown in FIG. 1A is changed to the cross-linked polyolefin film S1 after heat seal as shown in FIG. 1C. Remains as a film and functions as an insulating film. Further, as shown in FIG. 1 (d), the sealant of the battery packaging material of the present invention is a laminate of a polyolefin resin S1 crosslinked to a gel fraction of 0.5% to 80% and an acid-modified polyolefin resin S2c. After formation, the laminate may be crosslinked to a gel fraction of 0.5% to 80%. The laminate may be formed by a co-extrusion method,
The polyolefin film may be formed by extruding an acid-modified polyolefin into an extruded film. In this case, since it is cross-linked as a laminate, when the package material is hermetically sealed, the layer structure before pressurization at the lead wire portion shown in FIG. As shown in the figure, a polyolefin film S1 was used as the crosslinked laminate.
And the acid-modified polyolefin layer S2c remains as a film and functions as an insulating film. Gel fraction referred to in the present invention,
An index indicating the degree of cross-linking of cross-linked polyolefin by electron beam, ultraviolet ray, gamma ray, thermal cross-linking, etc., and indicates the percentage of gel (insoluble polymer chain) in cross-linked polyolefin resin insoluble in solvents such as xylene. Things.

The crosslinking will be described. When a polyethylene resin is irradiated with an electron beam or the like, the polyethylene resin undergoes electron beam cross-linking, thereby causing cross-linking within the molecule. At room temperature, of course, mechanical strength at high temperatures above the melting point, such as tensile strength, piercing strength, and compressive strength. Is improved. For example, polyethylene having a melting point of 105 ° C. and a gel fraction of 20% and 50%
%, The crosslinked resin material is 190 ° C., the surface pressure is 1.0 MPa, the high temperature at 3 seconds, the amount of compressive strain is less than the uncrosslinked resin material, and the uncrosslinked resin is 80%. 20%
The gel content is 60% for the resin material and 40% for the 50% gel product. However, ordinary polypropylene is decomposed by irradiation with an electron beam or the like. However, polypropylene has a polyethylene component, a butene component, and ethylene, butene, and propylene.
Terpolymer component consisting of component copolymer, density 900
kg / m ³ of low-crystalline ethylene-butene copolymer, amorphous ethylene-propylene copolymer, propylene α
-By adding 5% or more of an olefin copolymer component, a butadiene component, etc., these are cross-linked by electron beams, thereby causing cross-linking in the molecule. Tensile strength, piercing strength,
Compressive strength is improved.

For example, a component consisting of a copolymer of ethylene and butene is added to 10% so that the ethylene content is 10%.
% Of a polypropylene having a melting point of 145 ° C. and a crosslinked resin having a gel fraction of 20% and 50% is 190 ° C. and a surface pressure of 1.0 MPa compared with an uncrosslinked resin.
a, High temperature at 3 seconds, small amount of compressive strain, 50% for 20% gel fraction resin, 35% for 50% gel fraction product compared to 70% for uncrosslinked product. Further, even when compared at the same thickness, the crosslinked polyethylene, acid-modified polyethylene, polypropylene and acid-modified polypropylene have a small edge (so-called burr) on the tab 4 at the time of heat sealing as compared with the uncrosslinked polyethylene. This also has the effect of preventing a short circuit due to a pinhole generated in the above.

As the polypropylene, homotype polypropylene, random type polypropylene and block type polypropylene can be used. As the polyethylene, high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, or the like can be used. In addition, acid-modified polypropylene, propylene grafted unsaturated carboxylic acid,
As the acid-modified polyethylene, it is preferable to use a polyethylene grafted with an unsaturated carboxylic acid. Alternatively, as the acid-modified polyolefin resin, an unsaturated carboxy-grafted polyolefin, a metal cross-linked polyethylene, a copolymer of ethylene and an acrylic acid or methacrylic acid derivative, a copolymer of ethylene and phenol acetate, or the like can also be used. .

The electron-crosslinked acid-modified polypropylene used as a heat seal layer of the battery packaging material of the present invention has an adhesive property to a metal and has no adhesive property to a metal in a heat seal layer. In addition, it is not necessary to interpose a heat-sealing film for a lead wire on both the heat seal layer and the lead wire between the battery lead wire portion and the package. However, when the suitability for heat sealing is reduced due to the crosslinking, a film for a lead wire may be used for the purpose of low-temperature sealing and the like, as shown in FIG. A lead film 6 is interposed between the exterior body 5 and the lead wire 4.
As shown in (a) and FIG. 6 (b), an outer package is provided by placing lead film 6 above and below the hermetically sealed portion of the lead wire 4 of the battery body 2 (actually fixed by a temporary seal). 5
And heat-seal it while holding the lead wire portion to seal. FIG. 6D or FIG. 6E shows a method of interposing the lead wire film 6 in the lead wire 4.
As shown in (1), a film of the lead wire film 6 may be wound around a predetermined position of the lead wire 4.

When the film for a lead wire is used, specifically, a film made of an acid-modified polyolefin having thermal adhesion to both the cross-linked acid-modified polyolefin and the lead wire is used. Examples of the acid-modified polyolefin resin include unsaturated carboxy-grafted polyolefin, metal-crosslinked polyethylene, a copolymer of ethylene and an acrylic acid or methacrylic acid derivative, a simple substance of a copolymer of ethylene and phenol acetate, or a blend thereof. Can be used.

The thickness of the lead wire film 20 may be at least 1/3 of the thickness of the lead wire used. For example, if the lead wire has a thickness of 100 μm, the lead wire film 20 may have a thickness of 100 μm. Should be about 30 μm or more.

When an exterior body is formed using the battery packaging material of the present invention, and the battery body is inserted into the exterior body and the periphery is sealed by heat sealing, the sealing state at the lead wire portion is as shown in FIG. c) or as shown in FIG. 1 (f), the sealant layer or a part of the sealant layer cross-linked between the barrier layer and the lead remains in the form of a film, so that a short circuit which is an object of the present invention can be avoided. Things.

The battery packaging material forms an outer package for packaging the battery body. Depending on the type of the outer package, a pouch type as shown in FIG. 3 and a pouch type as shown in FIGS. 4 (a) and 4 (b) are used. ) Or an embossed type as shown in FIG. The pouch type includes a bag type such as a three-sided seal, a four-sided seal, and a pillow type.
Is illustrated as a pillow type. The embossed type may have a concave portion on one side as shown in FIG. 4 (a) or a concave portion on both sides as shown in FIG. The four sides may be heat sealed. There is also a type in which a concave portion is formed on both sides of a folded portion as shown in FIG. 4C, and the battery is housed and three sides are heat-sealed. When the battery packaging material is an embossed type, as shown in FIGS. 5A to 5D, the laminated packaging material 10 is press-formed to form the concave portion 7.

Next, each layer constituting the battery packaging material of the present invention will be described. The base material layer 11 in the exterior body
Is made of a stretched polyester or nylon film. At this time, examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolymerized polyester, and polycarbonate. Nylon is a polyamide resin, that is, nylon 6, nylon 6,6, nylon 6 and nylon 6,6.
And nylon 6,10, polymethaxylylene adipamide (MXD6) and the like. The base material layer 1
Reference numeral 1 denotes a portion which is in direct contact with hardware when used as a battery, and thus a resin layer having an insulating property is basically preferable. In consideration of the presence of pinholes in the film alone and the occurrence of pinholes during processing, the base material layer needs to have a thickness of 6 μm or more, and a preferred thickness is 12 to 30 μm.
μm.

The base layer 11 can be laminated to improve the pinhole resistance and the insulation when the battery is used as an outer package. When the base material layer is formed into a laminate, the base material layer includes at least one resin layer of two or more layers, and each layer has a thickness of 6 μm or more, preferably 12 to 30 μm.
Examples of laminating the substrate layer include the following 1) to 8). 1) Stretched polyethylene terephthalate / stretched nylon 2) Stretched nylon / stretched stretched polyethylene terephthalate Also, the mechanical suitability of packaging materials (stability of transportation in packaging machines and processing machines), surface protection (heat resistance, electrolyte resistance) ) When the exterior body for batteries is embossed as a secondary process, the purpose is to reduce the frictional resistance between the mold and the substrate layer during embossing, or to protect the substrate layer when an electrolytic solution is attached. In order to do so, the base material layer is multi-layered, and a fluorine-based resin layer, an acrylic-based resin layer, a silicone-based resin layer, a polyester-based resin layer, or a resin layer made of a blend thereof is provided on the surface of the base material layer. preferable. For example, 3) Fluorine-based resin / stretched polyethylene terephthalate (fluorine-based resin is formed into a film or liquid coating and then dried) 4) Silicone-based resin / stretched polyethylene terephthalate (silicone-based resin is film-like or liquid 5) Fluorine resin / stretched polyethylene terephthalate /
Stretched nylon 6) Silicone resin / Stretched polyethylene terephthalate / Stretched nylon 7) Acrylic resin / Stretched nylon (Acrylic resin is cured in film form or liquid coating and then dried) 8) Acrylic resin + polysiloxane graft acrylic resin / Stretched nylon (acrylic resin film
Or cured by drying after liquid coating)

The barrier layer 12 is a layer for preventing water vapor from particularly entering the inside of the battery from the outside, and stabilizes pinholes and processing suitability (pouching, embossability) of the barrier layer alone. Metal having a thickness of 15 μm or more, such as aluminum or nickel, or an inorganic compound, for example, silicon oxide, alumina or the like, and a film formed by vapor deposition of alumina or the like to have a pinhole resistance. Is 20-80 μm aluminum. In order to further improve the occurrence of pinholes and to make the type of the battery exterior body an embossed type, in order to prevent the occurrence of cracks and the like in the embossing, the present inventors made the material of aluminum used as the barrier layer However, by setting the iron content to 0.3 to 9.0% by weight, preferably 0.7 to 2.0% by weight, the extensibility of aluminum is better than that of aluminum not containing iron. It has also been found that the occurrence of pinholes due to bending as a laminate is reduced, and that the side walls can be easily formed when the embossed type exterior body is molded. When the iron content is less than 0.3% by weight, effects such as prevention of pinhole generation and improvement of embossability are not recognized, and the iron content of the aluminum exceeds 9.0% by weight. In such a case, the flexibility as aluminum is impaired, and the bag-making properties of the laminate deteriorate.

Further, the aluminum produced by cold rolling has its flexibility and flexibility under the conditions of annealing (so-called annealing treatment).
Although the strength and hardness of the waist change, the aluminum used in the present invention is harder than the hard treated product without annealing.
Aluminum with a tendency to soften slightly or completely annealed is preferred. The degree of flexibility, waist strength, and hardness of aluminum, that is, the conditions of annealing,
What is necessary is just to select suitably according to workability (pouching, embossing). For example, in order to prevent wrinkles and pinholes during embossing, it is desirable to use annealed soft aluminum according to the degree of forming.

The present inventors have been able to obtain a laminate that is satisfactory as the packaging material by subjecting the front and back surfaces of aluminum, which is the barrier layer 12 of the battery packaging material, to a chemical conversion treatment. The chemical conversion treatment specifically includes forming an acid-resistant film such as a phosphate, a chromate, a fluoride, and a triazine thiol compound. Chrome (3)
Phosphoric acid chromate treatment using a compound composed of a compound and phosphoric acid is favorable. Alternatively, a chemical conversion treating agent containing a metal such as molybdenum, titanium, zircon, or a metal salt in a resin component containing at least a phenol resin was good. The formation of the acid-resistant film prevents the delamination between aluminum and the substrate layer during embossing, and dissolves and corrodes the aluminum surface by hydrogen fluoride generated by the reaction between the battery electrolyte and moisture. In particular, it prevents the aluminum oxide present on the surface of aluminum from dissolving and corroding, and improves the adhesiveness (wetting) of the aluminum surface.
The effect of preventing delamination between the base material layer 11 and the aluminum 12 during heat sealing and the effect of preventing delamination on the inner surface of the aluminum by hydrogen fluoride generated by the reaction between the electrolyte and moisture were obtained. As a result of studying the effect of chemical conversion treatment on the aluminum surface using various substances, among the above-mentioned acid-resistant film-forming substances, phenolic resin, chromium fluoride (3) compound, and phosphoric acid The phosphoric acid chromate treatment using the treated product was good. Or a resin component containing at least a phenolic resin, a metal such as molybdenum, titanium, zircon,
Alternatively, the chemical conversion treatment containing a metal salt was good.

When the exterior body is of a pouch type, the chemical conversion treatment of aluminum may be performed on one side of only the heat seal layer side or on both sides of the base material layer side and the heat seal layer side. When the battery exterior body is an embossed type, delamination between aluminum and the base layer during embossing can be prevented by performing a chemical conversion treatment on both surfaces of aluminum.

As described above, the sealant layer of the battery packaging material of the present invention comprises a laminate comprising a multilayer sealant layer, wherein the innermost layer of the multilayer sealant layer is an acid-modified polyolefin. It contains a polyolefin layer cross-linked with aluminum so that the gel fraction is at least 0.5% to 80%.

In the case of laminating the battery packaging material of the present invention, the adhesion between the chemical conversion treatment layer provided on the barrier layer and the sealant layer may be caused, for example, by a reaction between a liquid electrolyte and water in a lithium ion battery or the like. In order to prevent delamination due to hydrofluoric acid or the like, it is desirable to perform the following lamination and adhesion stabilization treatment.

The present inventors have conducted intensive studies on a laminating method showing a stable adhesive strength. As a result, after dry-laminating at least the chemical conversion-treated barrier layer 12 and the base material layer 11 on the surface on which the sealant layer is to be laminated, FIG. As shown in FIG. 2 (a) or FIG. 2 (b), lamination 13d is performed by a dry lamination method as an adhesion method between the chemical conversion treatment layer provided on the barrier layer and the sealant layer, or FIG.
As shown in (c), after the emulsion of the acid-modified polyolefin is applied to the chemical conversion treatment layer and dried and baked (13h), a film serving as a sealant layer is laminated by a heat lamination method to obtain a predetermined adhesion. It was confirmed that strength was obtained.

Further, it was confirmed that stable adhesive strength could be obtained by the following laminating method. For example, the base material layer 11 and one surface of the barrier layer 12 are dry-laminated, and as shown in FIG. 2D, an acid-modified polyolefin 13e is extruded on the other surface (chemical conversion treatment layer) of the barrier layer 12 to form a sealant. When the layer 14 is sandwich-laminated, or after the acid-modified polyolefin resin 13 and the sealant layer are co-extruded to form a laminate, the obtained laminate is subjected to conditions in which the acid-modified polyolefin resin 13e has a softening point or higher. Thus, a laminate having a predetermined adhesive strength could be obtained. As a specific method of the heating, there are methods such as a hot roll contact type, a hot air type, near or far infrared rays, but any heating method may be used in the present invention, and as described above, the adhesive resin is softened. What is necessary is just to be able to heat above the point temperature.

As another method, the above-mentioned sandwich lamination or co-extrusion lamination may be performed by heating the aluminum 12 to a condition that the surface temperature of the sealant layer side of the aluminum 12 reaches the softening point of the acid-modified polyolefin resin. A laminate having stable adhesive strength was obtained. It is also possible to use a polyethylene resin as the adhesive resin, but in this case, it is desirable to laminate the extruded polyethylene molten resin film while performing ozone treatment on the laminating surface on the aluminum side.

In the battery packaging material of the present invention, the above-mentioned layers in the laminate forming the outer package have appropriate film-forming properties, lamination processing, and suitability for secondary processing of final products (pouching, embossing). For the purpose of improvement and stabilization, surface activation treatment such as corona treatment, blast treatment, oxidation treatment, and ozone treatment may be performed.

[0033]

EXAMPLES The packaging material for a battery of the present invention will be described more specifically with reference to examples. (1) Chemical conversion treatment layer The chemical conversion treatment applied to the barrier layer of the exterior body was performed by a roll coating method using an aqueous solution containing a phenol resin, a chromium fluoride (3) compound, and phosphoric acid as a treatment liquid in both the examples and the comparative examples. And baked under the condition that the film temperature is 180 ° C. or higher. The amount of chromium applied is 1 mg / m ²
(Dry weight). (2) Type of exterior body In the following examples and comparative examples, the pouch type exterior body has a width of 30 mm and a length of 50 mm (both inner dimensions), and in the case of an embossed type exterior body, 2. Each of them was a single-sided embossed type, the shape of the concave portion (cavity) of the mold was 30 mm × 50 mm, and the depth was 3.
It was press-molded at 5 mm and the moldability was evaluated. In each of the examples of the embossed type, a non-molded one of the embossed laminate was used as the lid. (3) Lead wire Each of the lead wires had a thickness of 100 μm and a width of 4 mm. (4) Sealant Layer and Adhesive Resin Layer The acid-modified polyethylene used for the sealant layer and the adhesive resin layer is an unsaturated carboxylic acid-grafted polyethylene, and the acid-modified polypropylene is an unsaturated carboxylic acid-grafted random propylene (ethylene component amount 4%). %). (5) Crosslinking Treatment The crosslinking treatment was performed by an electron beam irradiation method. The treatment was carried out at a predetermined gel fraction between 100 and 400 KGy. In addition, the gel fraction was heated with xylene (100 ° C.) for 8 hours to determine the ratio of the amount of insoluble matter. (6) The abbreviations were as follows. Copolymer of ethylene, propylene and butene: EPB Copolymer of ethylene and butene: EB Copolymer of ethylene and propylene: EP Copolymer of propylene and butene: PB Polypropylene: PP Low-density polyethylene: LDPE Linear low High-density polyethylene: LLDPE Medium-density polyethylene: MDPE (7) Heat sealing conditions The heat sealing conditions for the lead wire portion in each of the Examples and Comparative Examples were performed under the following three conditions, and the presence or absence of short circuit after sealing was confirmed. Heat sealing conditions 200 ° C, 2.0MPa, 5.0s
ec [Example 1] A chemical conversion treatment was applied to both surfaces of 20 μm of aluminum, a stretched polyester film 12 μm was bonded to one surface of the chemical conversion treatment by a dry lamination method, and then a sealant was applied to the other surface of the chemical conversion-treated aluminum. Lamination was performed by a dry lamination method. A pouch was formed using the obtained laminate. Sealant is LDP
30 μm of E film was crosslinked so as to have a gel fraction of 0.8%, and on one surface thereof, an acid-modified polyethylene (unsaturated carboxylic acid grafted polyethylene) was extruded to a thickness of 20 μm. At the time of dry lamination, the crosslinked LDPE layer was used as a laminate surface. The battery body was inserted into a pouch and hermetically sealed by heat sealing to obtain Sample Example 1. Example 2 A chemical conversion treatment was applied to both surfaces of aluminum 20 μm, and a stretched polyester film 12 μm was adhered to one surface of the chemical conversion treatment by dry lamination, and then a sealant was dried on the other surface of the chemical conversion treated aluminum. They were bonded by a lamination method. A pouch was formed using the obtained laminate. Sealant layer is RP
EP was blended with P so that the ethylene content was 15%, and a film was formed to a thickness of 30 μm, and then crosslinked so as to have a gel fraction of 50%.
Extrusion film formation was performed to a thickness of 0 μm. When laminating the sealant, the crosslinked RPP was used as the laminate surface. Battery body,
It was inserted into a pouch and hermetically sealed by heat sealing to obtain Sample Example 2. Example 3 A chemical conversion treatment was applied to both surfaces of aluminum 20 μm, and a stretched polyester film 12 μm was bonded to one surface of the chemical conversion treatment by a dry lamination method. Is applied and dried (dry film thickness 5μ)
m) Further, after baking at a temperature of 195 ° C., a sealant film was bonded by a heat lamination method. A pouch was formed using the obtained laminate. The composition of the sealant film is MDPE 30 μm with a gel fraction of 30%.
Was extruded on one side to form a film. At the time of heat lamination, the surface of MDPE was used as the bonding surface. The battery body was inserted into a pouch and hermetically sealed by heat sealing to obtain Sample Example 3. Example 4 A chemical conversion treatment was performed on both surfaces of aluminum 20 μm, and a stretched polyester film 12 μm was bonded to one surface of the chemical conversion treatment by dry lamination, and then an acid-modified polypropylene was coated on the other surface of the chemical conversion treatment aluminum. Is applied and dried (dry film thickness 3μ)
m) Further, after baking at a temperature of 195 ° C., a sealant was bonded by a heat lamination method. A pouch was formed from the obtained laminate. The composition of the sealant is such that the amount of ethylene component is 15% in RPP.
A resin blended with a resin in a ratio of EP: EB: BP = 4: 2: 4 was formed into a film having a thickness of 30 μm, and crosslinked by electron beam irradiation so as to have a gel fraction of 75%. On one side, 20 μm of an acid-modified polypropylene resin was extruded to form a film. Example 5 A chemical conversion treatment was applied to both sides of 40 μm aluminum and a stretched nylon film 2 was applied to one surface of the chemical conversion treatment.
5 μm is laminated by a dry lamination method, and then
A sealant was bonded to another surface of the chemically treated aluminum by a dry lamination method. The obtained laminate was molded into a tray, and the unmolded laminate was used as a lid. The sealant layer was formed by extrusion-forming an acid-modified polyethylene on a 50 μm-crosslinked LLDPE film having a gel fraction of 42%. When laminating the sealant, LLDP
The E layer was a laminate surface. The battery main body was placed in a molding tray, the lid was covered, and the periphery thereof was hermetically sealed by heat sealing to obtain Sample Example 5. [Example 6] A chemical conversion treatment was applied to both surfaces of 40 µm of aluminum, and a stretched nylon film 2 was applied to one surface of the chemical conversion treatment.
5 μm is laminated by a dry lamination method, and then
A sealant film of 50 μm was dry-laminated on the other surface of the chemically treated aluminum. The obtained laminate was molded into a tray, and the unmolded laminate was used as a lid. The sealant film is formed by forming a resin in which EB is blended to a thickness of 30 μm so that the amount of the ethylene component is 9% in RPP, and cross-linking the gel fraction to be 0.8%. Then, an acid-modified polypropylene resin was extruded to a thickness of 20 μm. When laminating the sealant,
The PP layer was used as a laminate surface. The battery body was placed in a molding tray, the lid was covered, and the periphery thereof was hermetically sealed by heat sealing to obtain Sample Example 6.

[Comparative Example 1] A chemical conversion treatment was applied to both surfaces of 20 μm of aluminum, and a stretched polyester film 12 μm was adhered to one surface of the chemical conversion treatment by a dry laminating method. The sealant was attached by a dry lamination method. A pouch was formed using the obtained laminate. The sealant was formed by extruding an acid-modified polyethylene (unsaturated carboxylic acid grafted polyethylene) to a thickness of 20 μm on one side of a 30 μm LDPE film. At the time of dry lamination, the crosslinked LDPE layer was used as a laminate surface. The battery body was inserted into a pouch and hermetically sealed by heat sealing to obtain Sample Comparative Example 1. [Comparative Example 2] A chemical conversion treatment was applied to both surfaces of 20 μm of aluminum, a 12 μm stretched polyester film was bonded to one surface of the chemical conversion treatment by a dry lamination method, and then a sealant was dried on the other surface of the aluminum subjected to the chemical conversion treatment. They were bonded by a lamination method. A pouch was formed using the obtained laminate. Sealant layer is RP
An acid-modified polypropylene was extruded to a thickness of 20 on one side of a P30 μm thick film. When laminating the sealant, the crosslinked RPP was used as the laminate surface. The battery body was inserted into a pouch and hermetically sealed by heat sealing to obtain Sample Comparative Example 2. [Comparative Example 3] A chemical conversion treatment was applied to both surfaces of 40 μm aluminum, and a stretched nylon film 2 was applied to one surface of the chemical conversion treatment.
5 μm is laminated by a dry lamination method, and then
The other surface of the chemically treated aluminum was extruded with an acid-modified polypropylene resin as an adhesive resin, and a sealant was sandwich-laminated. A tray was formed using the obtained laminate, and a laminate that was not formed was used as a lid. The sealant is LLDPE 30μm and acid-modified polyethylene 20μm
Were co-extruded to form a film. When sandwich lamination,
Lamination was performed using the LLDPE surface as a laminate surface. The battery body was placed in a molding tray, the lid was covered, and the periphery thereof was hermetically sealed by heat sealing to obtain Sample Comparative Example 3. [Comparative Example 4] A stretched nylon film 25 µm was bonded to one surface of aluminum 40 µm by dry lamination, and then extruded to the other surface of aluminum to a thickness of 15 µm using an acid-modified polypropylene resin as an adhesive resin, and a sealant was applied. Sandwich lamination was performed, and the laminate was heated to a temperature higher than the softening point of the adhesive resin. A tray was formed using the obtained laminate, and a laminate that was not formed was used as a lid.
The sealant was formed by coextrusion of 30 μm of RPP and 20 μm of acid-modified polypropylene. At the time of sandwich lamination, RPP was used as a laminate surface. The battery body was placed in a molding tray, the lid was covered, and the periphery thereof was hermetically sealed by heat sealing to obtain Sample Comparative Example 4.

<Evaluation Method> (1) Presence / absence of short circuit between the lead wire and the barrier layer of the exterior body The short-circuit state between the lead wire section and the exterior body is determined by cutting the heat-sealed portion of the lead wire section and photographing the cross section. Check and, for those with a risk of short-circuit between the lead wire and the barrier layer of the exterior body, check the contact with a tester. According to the cross-sectional photograph, no film is seen between the lead wire and the barrier layer of the exterior body. The sample was on the verge of a short, and among them, the sample for which a short was confirmed by the tester was regarded as the number of shorts. 2) Confirmation of leakage and delamination The heat-sealed product was stored at 80 ° C. for 24 hours, and leakage of the content from the lead wire portion and delamination (hereinafter, delamination) on the content side of the laminate were confirmed. Contents: 3 g of a mixed solution of ethylene carbonate, diethyl carbonate, and dimethyl carbonate (1: 1: 1) so that the electrolytic solution becomes 1M LiPF ₆ .

<Results> In Examples 1 to 6,
Under each heat sealing condition, there was no short circuit or leakage of the contents at the lead wire portion. There was no delamination. In Comparative Example 1, 4 samples out of 500 samples were on the verge of a short, and 2 samples actually short-circuited. There were no leaks. In Comparative Example 2,
In 12 of the 500 samples, short-circuiting was about to occur, and 6 actually short-circuited. There were no leaks. In Comparative Example 3, short-circuit occurred in 15 out of 500 samples, and there was no leakage. Delamination was observed in 200 out of 500 samples between the aluminum and the adhesive resin layer. In Comparative Example 4, 15 samples out of 500 samples were on the verge of short-circuiting, and 12 samples actually short-circuited. There was no leakage, but 500
Delamination occurred between aluminum and the adhesive resin layer in 190 of the samples.

[0037]

As described above, in the battery packaging material of the present invention, the sealant layer is composed of a laminate composed of multiple layers, and the innermost layer of the multilayer sealant layer is an acid-modified polyolefin. By including a polyolefin layer crosslinked so that the gel fraction is at least 0.5% to 80%, the battery body is housed in the pouch or embossed portion of the outer package, and the periphery thereof is heat-sealed and sealed. In this case, since the cross-linked sealant layer functions as an insulating layer, there is no possibility that the barrier layer of the exterior body and the lead wire will contact (short). Also,
The chemical conversion treatment applied to both surfaces of the aluminum of the exterior body can prevent delamination between the base material layer and the aluminum at the time of embossing and heat sealing. When formed by a laminating method, a heat laminating method, a sandwich laminating method, or a co-extrusion laminating method, the heat generated by the reaction between the electrolyte of the battery and moisture due to heating during the formation of the laminate or heating after the formation of the laminate. This is an exterior body that can prevent corrosion of the aluminum surface due to hydrogen chloride, thereby also preventing delamination between the aluminum and the content-side layer.

[Brief description of the drawings]

FIG. 1 is a view illustrating a battery packaging material of the present invention;
(A) a cross-sectional view showing a positional relationship between a packaging material for a battery, a film for a lead wire, and a lead wire showing a layer structure,
(B) is a cross-sectional view illustrating a state in which the lead wire, the lead wire film, and the outer package are in contact with each other at the lead wire portion before heat sealing, and (c) is a schematic cross-sectional view of the lead wire portion after heat sealing. is there. (D), (e), and (f) are the same explanatory diagrams at the time of using the battery packaging material which has another sealant composition.

FIG. 2 is a cross-sectional view illustrating an example of a layer configuration of a laminate forming an exterior body of a battery.

FIG. 3 is a perspective view illustrating a pouch type exterior body of a battery.

FIG. 4 is a perspective view illustrating an embossed type exterior body of the battery.

FIG. 5 illustrates molding in an emboss type.
(A) a perspective view, (b) an embossed exterior body body,
(C) X ₂ -X ₂ parts cross-sectional view, an enlarged view (d) Y ₁ parts.

FIG. 6 is a diagram illustrating a method of mounting a lead wire film in bonding a battery packaging material and a lead wire.

FIG. 7 is a sectional view showing a state in which a barrier layer and a lead wire are short-circuited using a conventional lead wire film.

[Explanation of symbols]

 S Short-circuit portion between lead wire and barrier layer H Heat seal hot plate 1 Battery 2 Battery body 3 Cell (power storage unit) 4 Lead wire (electrode) 5 Outer body 6 Lead film 7 Depression 8 Side wall 9 Sealing 10 Lamination Body (packaging material for battery) 11 Base layer 12 Aluminum (barrier layer) 13 Adhesive layer 13d Dry laminate layer 13h Baking layer of acid-modified polyolefin 13e Extruded layer of acid-modified polyolefin 14 Sealant layer S1 Outer layer of sealant layer S2 Sealant layer Intermediate layer S3 Inner layer of sealant layer 15 Chemical conversion treatment layer 16 Substrate side dry laminate layer 20 Press molded part 21 Male type 22 Female type 23 Cavity

Continued on the front page (72) Inventor Masataka Okushita 1-1-1 Ichigaya-Kaga-cho, Shinjuku-ku, Tokyo F-term within Dai Nippon Printing Co., Ltd. 5H011 AA03 CC02 CC06 CC10 DD03 DD09 DD13 DD14 DD23 EE04 FF04 GG08 HH02 HH13 KK02

Claims (9)

[Claims] 1. A packaging material for forming a battery exterior body in which a battery main body is inserted and a peripheral portion is sealed by heat sealing, wherein at least a base layer, an adhesive layer 1, aluminum, a chemical conversion treatment layer, an adhesive layer 2, It is composed of a laminate composed of a multilayer sealant layer, wherein the innermost layer of the multilayer sealant layer is an acid-modified polyolefin, and the gel fraction between the acid-modified polyolefin and aluminum is at least 0.5% to 80%. A packaging material comprising a crosslinked polyolefin layer. 2. The laminate according to claim 1, wherein the laminate comprises a base material layer, an adhesive layer 1, a chemical conversion layer 1, aluminum, a chemical conversion layer 2, an adhesive layer 2, and a multilayer sealant layer. Packaging materials for batteries. 3. The battery packaging material according to claim 1, wherein the polyolefin is polypropylene. 4. The battery packaging material according to claim 1, wherein the polyolefin is polyethylene. 5. The battery packaging material according to claim 1, wherein said adhesive layer 1 and said adhesive layer 2 are formed by a dry lamination method. 6. The packaging material for a battery according to claim 1, wherein at least the adhesive layer 2 is a coating and baking layer of an acid-modified polyolefin. 7. The packaging material for a battery according to claim 1, wherein at least the adhesive layer 2 is an extruded layer of an acid-modified polyolefin. 8. The packaging material for a battery according to claim 1, wherein an adhesive film is interposed between the outer package of the battery and a lead wire portion of the battery main body. 9. A battery, wherein the battery body is inserted into an outer package of the battery comprising the battery packaging material according to any one of claims 1 to 8, and the periphery is heat-sealed to seal the battery.