WO2018164219A1 - Packaging material for battery, method for manufacturing packaging material for battery, and battery - Google Patents

Abstract

Provided is a packaging material for batteries which is flexible and in which a plurality of films are laminated, the packaging material for batteries comprising a film that can be heat welded, a plurality of gas barrier films disposed laminated on one surface side of the film that can be heat welded, and a plurality of adhesive layers disposed between the plurality of films. The gas barrier films each comprise a resin substrate and a gas barrier membrane which includes an inorganic substance and is disposed on one or both surface sides of the resin substrate. From among the plurality of adhesive layers, at least the adhesive layer positioned between the film that can be heat welded and a gas barrier film exhibits electrolyte solution resistance.

Description

Battery outer packaging material, battery outer packaging material manufacturing method, and battery

The present disclosure relates to a battery outer packaging material, a battery outer packaging manufacturing method, and a battery.

A battery usually has a power generation element such as an electrode and an electrolyte, and an exterior body that seals the power generation element.
As the outer package, for example, a battery outer packaging material that is a laminate having a resin film, a metal layer, and a heat-welded film, and an adhesive layer disposed between the films is used (for example, Patent Document 1). The battery outer packaging material is used, for example, as a battery outer package by sandwiching a power generation element between battery outer packaging materials and thermally welding the outer periphery of the battery outer packaging material. Further, the battery outer packaging material is used after being press-molded according to the thickness, shape, etc. of the power generation element as required.

JP 2013-196947 A

By the way, in recent years, batteries are used in various devices, and their shapes are diversified. As an example, a battery having flexibility is required.
On the other hand, for example, an outer packaging material for a battery having a metal layer as shown in Patent Document 1 usually has formability but low flexibility. Therefore, it is difficult to apply a battery outer packaging material having a metal layer to a battery having flexibility.
Further, the battery outer packaging material is also required to have resistance to an electrolytic solution.
The present disclosure has been made in view of the above circumstances, and has as its main purpose to have a battery outer packaging material having good flexibility and resistance to electrolyte.

The present disclosure is a battery outer packaging material that has flexibility and a plurality of films laminated, and is arranged to be laminated on one surface side of the thermally weldable film and the thermally weldable film. It has a plurality of gas barrier films and a plurality of adhesive layers arranged between the plurality of films, the gas barrier film is arranged on one or both sides of the resin substrate and the resin substrate, A battery barrier film comprising an inorganic substance, and among the plurality of adhesive layers, at least an adhesive layer disposed between the heat-weldable film and the gas barrier film has an electrolyte solution resistance. Providing materials.

Further, the present disclosure is a battery outer packaging material in which a plurality of films are laminated, and a heat-weldable film and a plurality of gas barrier films arranged on one side of the heat-weldable film. And a plurality of adhesive layers disposed between the plurality of films,
The gas barrier film includes a resin base material and a gas barrier film including an inorganic substance disposed on one or both surfaces of the resin base material, and at least the heat-weldable film among the plurality of adhesive layers. And the gas barrier film have an electrolyte solution resistance, and the battery outer packaging material has a tensile elastic modulus (MPa) × (thickness (mm)) ³ <1.0. Provided is a battery outer packaging material that satisfies the relationship of (MPa · mm ³ ).

According to the present disclosure, an outer packaging material for a battery having good flexibility and electrolyte solution resistance can be obtained.

It is a schematic sectional drawing which illustrates the battery outer packaging material of this indication. It is a schematic sectional drawing which illustrates the battery outer packaging material of this indication.

An embodiment of the battery outer packaging material of the present disclosure will be described. In the following description, “battery packaging material” may be simply referred to as “packaging material”.
As described above, in recent years, batteries have been used in various devices, and their shapes have diversified.
For example, in recent years, as a new type of electronic device, a wearable terminal that can be operated while being worn by a user has been rapidly developed. A wearable terminal is required to have high followability to the movement of the user's body. Accordingly, a battery having flexibility is demanded.
On the other hand, for example, an outer packaging material for a battery having a metal layer as shown in Patent Document 1 usually has formability but low flexibility.

One reason for the low flexibility of the battery outer packaging material having a metal layer is that, for example, a relatively thick metal layer of about 40 μm is used. This is because the metal layer in the outer packaging material is configured to impart gas barrier properties, and in order to impart good gas barrier properties, the thickness of the metal layer needs to be relatively thick. Moreover, in the outer packaging material, for example, in order to suppress the occurrence of pinholes in the metal layer during press molding, it is necessary to increase the thickness of the metal layer.

The inventors of the present disclosure have found that desired gas barrier properties and flexibility can be achieved by using a plurality of gas barrier films instead of the metal layer.
On the other hand, it has been found that an outer packaging material using a plurality of gas barrier films has low resistance to electrolytic solution. With regard to this point, as a result of further studies by the inventors of the present disclosure, the electrolytic solution resistance of the adhesive layer disposed between the films constituting the outer packaging material greatly affects the electrolytic solution resistance of the outer packaging material. I found out that The present disclosure is an invention based on the above findings.

That is, the battery outer packaging material of the present disclosure is a battery outer packaging material having flexibility and a plurality of films laminated, and one surface side of the heat-weldable film and the heat-weldable film. A plurality of gas barrier films disposed in a stack and a plurality of adhesive layers disposed between the plurality of films, wherein the gas barrier film comprises a resin substrate and one or both of the resin substrates. A gas barrier film containing an inorganic substance, and among the plurality of adhesive layers, at least an adhesive layer disposed between the heat-weldable film and the gas barrier film is an anti-electrolytic solution. Have sex.

Further, the battery outer packaging material of the present disclosure is a battery outer packaging material in which a plurality of films are laminated, and is arranged by being laminated on one surface side of the thermally weldable film and the thermally weldable film. A plurality of gas barrier films, and a plurality of adhesive layers disposed between the plurality of films, the gas barrier film being disposed on one or both sides of the resin base material and the resin base material. A gas barrier film containing an inorganic substance, and among the plurality of adhesive layers, at least an adhesive layer disposed between the heat-weldable film and the gas barrier film has an electrolyte resistance. The battery outer packaging material satisfies the relationship of tensile elastic modulus (MPa) × (thickness (mm)) ³ <1.0 (MPa · mm ³ ).

In addition, in the present disclosure, “gas barrier property” and “gas barrier performance” mean functions to prevent permeation of gas such as oxygen and / or water vapor unless otherwise specified.

(Flexibility)
In the present disclosure, “the outer packaging material has flexibility” means that when the outer packaging material is bent, the film and the adhesive layer constituting the outer packaging material are not damaged to such an extent that the gas barrier property can be maintained. Specifically, “the outer packaging material has flexibility” means that at least one of the following characteristics 1 and 2 is satisfied. The outer packaging material of the present invention particularly preferably satisfies both characteristics 1 and 2.

Characteristic 1: About the test piece (outer packaging material) after the third bending treatment, the water vapor permeability is 0.5 g / (m ² · 24 h) or less and the oxygen permeability is 0.5 cc / (m ² · 24 h).・ Atm) It must be below.
Characteristic 2: The outer packaging material satisfies the relationship of tensile elastic modulus (Mpa) × (thickness (mm)) ³ <1.0 (MPa · mm ³ ).

In flexible batteries, it is important that the outer packaging material has such flexibility. For example, a flexible battery used for a wearable terminal having high followability to the movement of the user's body is required to use an outer packaging material having resistance to such bendability.

Regarding the characteristic 1, the third bending process is performed under the following conditions. A rectangular test piece having a width of 210 mm and a length of 297 mm (A4 size) is prepared, and bending processing is performed three times using a gelboflex tester (manufactured by Tester Sangyo Co., Ltd., model name: BE1006) in accordance with ASTM F392. . Moreover, the measuring method of water vapor permeability and oxygen permeability is the same as the method described in the section “2. Characteristics of outer packaging material” described later. From the viewpoint of particularly excellent flexibility, the water vapor permeability of the outer packaging material after the third bending treatment is 0.3 g / (m ² · 24 h) or less, and the oxygen permeability after the third bending treatment is 0.3 cc. / (M ² · 24h · atm) or less is particularly preferable. Examples of the lower limit of water vapor permeability include 0.0 g / (m ² · 24 h) and 0.1 g / (m ² · 24 h). ^{0cc / (m 2 · 24h ·} atm), 0.1cc / (m 2 · 24h · atm) , and the like.

Regarding the characteristic 2, the tensile elastic modulus of the outer packaging material is determined as follows. The tensile modulus was measured in accordance with JIS K7161-1: 2014 (Plastics-Determination of tensile properties-Part 1: General rules), and the outer packaging material was cut into a rectangle with a width of 15 mm, and a sample was collected. Using a tensile tester, a method is used in which the tensile elastic modulus is measured under the conditions that the distance between chucks is 100 mm, the tensile speed is 100 mm / min, and the reserve force is used. The measurement environment is an environment with a temperature of 23 ° C. and a relative humidity of 55%. The length of the sample is determined within a range in which a gripping tool is attached so that the length of the sample coincides with the axis of the testing machine and the gripping portion does not shift during measurement, and is, for example, about 120 mm. The tensile tester is preferably Instron 5565 (Instron Japan). Reserve, for example, ₀ stress sigma, and when suitable elastic modulus and the stress for the elastic modulus as E _t (reserve is unknown by the test in advance determined the predictive value of the elastic modulus and stress ( _Et / 10000) ≦ σ ₀ ≦ (E _t / 3000). In addition, since the value of a tensile elasticity modulus may change with directions in the surface of an outer packaging material, use of an in-plane average value is preferable. The average of the values of the eight conditions obtained by changing the condition in the in-plane direction of the outer packaging material by approximately 22.5 degrees can be regarded as the in-plane average value. In addition, when the sample of the eight conditions changed by 22.5 degrees cannot be collected because the outer packaging material is small, for example, the condition in the in-plane direction of the outer packaging material is substantially uniform (that is, 180 degrees is The possible number of samples are acquired so that the tensile elastic modulus of the outer packaging material is obtained.

From the viewpoint of excellent flexibility, the outer packaging material preferably satisfies the relationship 0.5 ≦ tensile modulus (Mpa) × (thickness (mm)) ³ ≦ 0.9 (MPa · mm ³ ), It is particularly preferable that the relationship of 0.5 ≦ tensile modulus (Mpa) × (thickness (mm)) ³ ≦ 0.7 (MPa · mm ³ ) is satisfied.

Further, the tensile modulus of the outer packaging material is not particularly limited, but from the viewpoint of excellent flexibility, it is preferably 1.0 GPa or more and 3.0 GPa or less, more preferably 1.1 GPa or more and 2.9 GPa or less, and further preferably 1 3 GPa or more and 2.8 GPa or less. In addition, the measuring method of a tensile elasticity modulus is as above-mentioned.

The outer packaging material of the present disclosure will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view illustrating an outer packaging material of the present disclosure. The outer packaging material 10 has flexibility. The outer packaging material 10 is a member in which a plurality of films are laminated. The outer packaging material 10 includes a heat-weldable film 1, a plurality of gas barrier films 2 disposed on one side of the heat-weldable film 1, and a plurality of adhesives disposed between the plurality of films. Layer 3. FIG. 1 shows an example in which two gas barrier films 2a and 2b are laminated and disposed on one surface side of a film 1 that can be thermally welded. The adhesive layer 3 is usually disposed between the heat-weldable film 1, the gas barrier film 2a, and the gas barrier film 2b. In the present disclosure, among the adhesive layers 3a and 3b, at least the adhesive layer 3a disposed between the heat-weldable film 1 and the gas barrier film 2a has an electrolytic solution resistance.
In addition, when the outer packaging material 10 is normally used for a battery, the heat-weldable film 1 is disposed on the power generation element side.

According to the present disclosure, by having a plurality of gas barrier films and an adhesive layer having an electrolytic solution resistance, it is possible to provide a battery packaging material having good flexibility and an electrolytic solution resistance.

Moreover, since the outer packaging material of this indication has favorable flexibility, the application to the outer packaging material of the battery which can track the motion of a wearable terminal is possible, for example.
Moreover, since the outer packaging material of this indication has favorable flexibility, it can make workability high. Therefore, it can be applied to, for example, a battery of various shapes, a small battery, and a thin film battery.
Hereinafter, details of the outer packaging material of the present disclosure will be described.

1. Configuration of outer packaging material The outer packaging material of the present disclosure has a structure in which a plurality of films are laminated. The outer packaging material includes a heat-weldable film, a plurality of gas barrier films, and an adhesive layer.

The thickness of the outer packaging material is not particularly limited, but from the viewpoint of flexibility, the upper limit is preferably 150 μm or less, 140 μm or less, 130 μm or less, 100 μm or less, 90 μm or less, and the lower limit is preferably 50 micrometers or more, 55 micrometers or more, 60 micrometers or more are mentioned. Further, preferable ranges of the thickness of the outer packaging material are 50 μm to 150 μm, 55 μm to 150 μm, 60 μm to 150 μm, 50 μm to 140 μm, 55 μm to 140 μm, 60 μm to 140 μm, 50 μm to 130 μm, 55 μm to 130 μm. In the following, 60 μm to 130 μm, 50 μm to 100 μm, 55 μm to 100 μm, 60 μm to 100 μm, 50 μm to 90 μm, 55 μm to 90 μm, 60 μm to 90 μm.

(1) Adhesive layer The adhesive layer in this indication is a layer arranged between a plurality of films. That is, the adhesive layer is disposed between all the films constituting the outer packaging material.
In the present disclosure, among the plurality of adhesive layers, at least the adhesive layer disposed between the heat-weldable film and the gas barrier film has an electrolytic solution resistance.
In the present disclosure, it is preferable that all of the plurality of adhesive layers have electrolytic solution resistance. Specifically, in the outer packaging material 10 shown in FIG. 1, it is preferable that all of the adhesive layers 3 a and 3 b have an electrolytic solution resistance. In the outer packaging material 10 shown in FIG. 2, the adhesive layers 3 a, 3 b, and 3 c All of these preferably have resistance to electrolytic solution.

“The adhesive layer has resistance to an electrolytic solution” usually means that the adhesive layer is hardly lowered by the electrolytic solution. The deterioration of the adhesive layer is usually defined by the peel strength.
The electrolytic solution resistance of the adhesive layer is, for example, the ratio of the peel strength (N / 15 mm) of the adhesive layer after the electrolytic solution resistance test to the peel strength (N / 15 mm) of the adhesive layer before the electrolytic solution resistance test described below ( The peel strength maintenance ratio) is 50% or more, preferably 70% or more, more preferably 80% or more, and still more preferably 90% or more.

Conditions for the electrolyte resistance test are as follows.
First, the outer packaging material is cut into 60 mm (vertical direction) × 150 mm (horizontal direction). Next, the cut battery packaging material is folded in two so that the films that can be thermally welded in the lateral direction are opposed to each other, and the laterally opposed one side and the longitudinal side are thermally welded. A bag-shaped outer packaging material having one side opened is produced. Next, 3 g of electrolytic solution is injected from the opening, and the opening is heat-welded with a width of 7 mm. Next, the part where the opening part of the packaging material for batteries was located is faced up, and it is left still for 24 hours in an 85 degreeC thermostat.

The measurement conditions for the peel strength of the adhesive layer are as follows.
A test piece cut into a strip shape with a width of 15 mm is prepared. Using a tensile tester (for example, a tensile tester manufactured by Shimadzu Corporation (trade name Tensilon Universal Material Tester RTG-1210 manufactured by A & D)) at 50 mm / mm, using two films in contact with the adhesive layer to be measured. Pull at a rate of minutes and measure the peel strength (N / 15 mm) of the specimen.

The adhesive layer only needs to have the above-described electrolytic solution resistance with respect to the electrolytic solution of the battery in which the outer packaging material of the present disclosure is used. For example, as a solvent, ethylene carbonate, diethyl carbonate: dimethyl It is preferable to have an electrolytic solution resistance to an electrolytic solution using a mixed solvent mixed at a ratio of carbonate = 1: 1: 1 and lithium hexafluorophosphate as an electrolyte.

The adhesive layer used in the present disclosure is not particularly limited as long as it has the above-described electrolytic solution resistance, and can be appropriately selected according to the type of the electrolytic solution in the battery in which the outer packaging material is used.
As the inventors of the present disclosure repeatedly researched, an acid-modified polyolefin having a melting temperature (melting point) of 50 ° C. or higher and 120 ° C. or lower is used as a main agent, and an epoxy resin having a weight average molecular weight of 50 or more and 2000 or lower is used as a curing agent. It was found that an adhesive layer using an adhesive exhibits good electrolytic solution resistance.

That is, in the present disclosure, the adhesive layer having an electrolytic solution resistance includes a cured product of an acid-modified polyolefin having a melting temperature of 50 ° C. or more and 120 ° C. or less and an epoxy resin having a weight average molecular weight of 50 or more and 2000 or less. Is preferred.
The structure and properties of the cured product contained in the adhesive layer vary depending on, for example, the type of acidic polyolefin, the type of epoxy resin, the presence or absence of additives, curing conditions, etc., and thus it is usually difficult to specify directly. is there. Therefore, hereinafter, the cured product contained in the adhesive layer will be described with reference to the components of the adhesive before curing.

As the acid-modified polyolefin, it is preferable to use a polyolefin modified with an unsaturated carboxylic acid or an acid anhydride thereof. Furthermore, the acid-modified polyolefin may be further modified with a (meth) acrylic acid ester. The modified polyolefin further modified with (meth) acrylic acid ester is obtained by acid-modifying polyolefin by using unsaturated carboxylic acid or its acid anhydride and (meth) acrylic acid ester in combination. is there. In the present disclosure, “(meth) acrylic acid ester” means “acrylic acid ester” or “methacrylic acid ester”. One type of acid-modified polyolefin may be used alone, or two or more types may be used in combination.

The polyolefin to be acid-modified is not particularly limited as long as it is a resin containing an olefin as at least a monomer unit. The polyolefin can be composed of, for example, at least one of polyethylene and polypropylene, and is preferably composed of polypropylene. The polyethylene can be composed of, for example, at least one of homopolyethylene and ethylene copolymer. Polypropylene can be composed of, for example, at least one of homopolypropylene and propylene copolymer. Examples of the propylene copolymer include copolymers of propylene and other olefins such as ethylene-propylene copolymer, propylene-butene copolymer, and ethylene-propylene-butene copolymer. The proportion of propylene units contained in polypropylene is preferably 50 mol% or more and 100 mol% or less, and more preferably 80 mol% or more and 100 mol% or less, from the viewpoint of further improving the insulation and durability of the outer packaging material. More preferred. Moreover, it is preferable to set it as 50 mol% or more and 100 mol% or less, and the ratio of the ethylene unit contained in polyethylene shall be 80 mol% or more and 100 mol% or less from a viewpoint of improving the insulation and durability of an outer packaging material. It is more preferable. Each of the ethylene copolymer and the propylene copolymer may be a random copolymer or a block copolymer. In addition, the ethylene copolymer and the propylene copolymer may each be crystalline or amorphous, and may be a copolymer or a mixture thereof. The polyolefin may be formed of one type of homopolymer or copolymer, or may be formed of two or more types of homopolymer or copolymer.

Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid, and crotonic acid. Moreover, as an acid anhydride, the acid anhydride of the unsaturated carboxylic acid illustrated above is preferable, and maleic anhydride and itaconic anhydride are more preferable. The acid-modified polyolefin may be one modified with one type of unsaturated carboxylic acid or its acid anhydride, or one modified with two or more types of unsaturated carboxylic acid or its acid anhydride. Also good.

Examples of the (meth) acrylic acid ester include an esterified product of (meth) acrylic acid and an alcohol having 1 to 30 carbon atoms, preferably (meth) acrylic acid and an alcohol having 1 to 20 carbon atoms. Examples include esterified products. Specific examples of (meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, (meth) Examples include octyl acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, and the like. In modification of polyolefin, only one type of (meth) acrylic acid ester may be used, or two or more types may be used.

The ratio of the unsaturated carboxylic acid or its acid anhydride in the acid-modified polyolefin is preferably 0.1% by mass or more and 30% by mass or less, and preferably 0.1% by mass or more and 20% by mass or less. More preferred. By setting it as such a range, the insulation and durability of an outer packaging material can be improved more.

The ratio of (meth) acrylic acid ester in the acid-modified polyolefin is preferably 0.1% by mass or more and 40% by mass or less, and more preferably 0.1% by mass or more and 30% by mass or less. By setting it as such a range, the insulation and durability of an outer packaging material can be improved more.

The weight average molecular weight of the acid-modified polyolefin is preferably 6000 or more and 200000 or less, and more preferably 8000 or more and 150,000 or less. In the present disclosure, the weight average molecular weight of the acid-modified polyolefin is a value measured by gel permeation chromatography (GPC) measured under conditions using polystyrene as a standard sample. Specific measurement conditions are as follows.

For gel permeation chromatography (GPC) measurement, “Waters, Alliance 2695” is used, three columns are used, and THF (tetrahydrofuran) is used as an eluent. As experimental conditions, an experiment is performed using a sample concentration of 0.5%, a flow rate of 1.0 ml / min, a sample injection amount of 50 μl, a measurement temperature of 40 ° C., and an RI detector. The calibration curve is prepared from “polystyrene standard sample TSK standard” manufactured by Tosoh Corporation.

The melting temperature of the acid-modified polyolefin is preferably 50 ° C. or higher and 120 ° C. or lower, and more preferably 50 ° C. or higher and 100 ° C. or lower. In the present disclosure, the melting temperature of the acid-modified polyolefin refers to a melting peak temperature in differential scanning calorimetry. Moreover, in this indication, it is preferable that the melting temperature of the hardened | cured material which comprises an contact bonding layer is the numerical range mentioned above. The melting temperature (melting temperature) of the cured product in the present disclosure can be measured using, for example, EXSTAR6000 manufactured by Seiko Instruments Inc. in accordance with the provisions of JIS K 7121: 2012.

In the acid-modified polyolefin, the method for modifying the polyolefin is not particularly limited, and for example, an unsaturated carboxylic acid or an acid anhydride thereof or a (meth) acrylic acid ester may be copolymerized with the polyolefin. Examples of such copolymerization include random copolymerization, block copolymerization, graft copolymerization (graft modification), and the like, and preferably graft copolymerization.

The epoxy resin is not particularly limited as long as it is a resin capable of forming a crosslinked structure with an epoxy group present in the molecule, and a known epoxy resin can be used. In the present disclosure, the weight average molecular weight of the epoxy resin may be in the range of 50 or more and 2000 or less. From the viewpoint of further improving the insulation and durability of the outer packaging material, the weight average molecular weight of the epoxy resin is preferably 100 or more and 1000 or less, more preferably 200 or more and 800 or less. In the present disclosure, the weight average molecular weight of the epoxy resin is a value measured by gel permeation chromatography (GPC) measured under conditions using polystyrene as a standard sample. Since the specific measurement conditions are the same as the measurement conditions for the acid-modified polyolefin described above, description thereof is omitted here.

(2) Gas barrier film The gas barrier film in this indication has a resin base material and the gas barrier film which is arranged on the single side or both sides of the resin base material and contains an inorganic substance. The said gas barrier film is arrange | positioned at the one surface side of the film which can be heat-welded, and mainly contributes to the gas barrier property of an outer packaging material.

(I) Gas barrier film | membrane The said gas barrier film | membrane is a film | membrane which is arrange | positioned at the single side | surface or both surfaces of the resin base material, and contains an inorganic substance. The gas barrier film mainly contributes to the gas barrier property of the gas barrier film.
Examples of inorganic substances include metals (including alloys) and inorganic compounds. As the gas barrier film containing an inorganic substance, for example, a metal film, a film containing an inorganic compound as a main component (hereinafter sometimes referred to as an inorganic compound film), and a mixed compound of an organic portion and an inorganic portion are used as a main component. And a film (sometimes referred to as an organic-inorganic composite film).

Examples of the metal constituting the metal film include metals such as aluminum, stainless steel, titanium, nickel, iron, copper, and alloys containing these metals. From the viewpoint of flexibility, the metal film is particularly preferably aluminum.

Examples of the inorganic compound constituting the inorganic compound film include compounds containing metal elements or non-metal elements such as silicon, aluminum, magnesium, calcium, potassium, tin, sodium, titanium, boron, yttrium, zirconium, cerium, and zinc. Is mentioned. Examples of the inorganic compound include inorganic oxides, inorganic oxynitrides, inorganic nitrides, inorganic oxide carbides, inorganic oxycarbonitrides, and silicon oxide zinc. Specifically, silicon oxide such as SiO ₂ , aluminum oxide such as Al ₂ O ₃ , magnesium oxide, titanium oxide, tin oxide, silicon zinc alloy oxide, indium alloy oxide, silicon nitride, Examples thereof include aluminum nitride, titanium nitride, and silicon oxynitride. An inorganic compound may be used independently and may mix and use the above-mentioned material in arbitrary ratios.

Examples of the mixed compound of the organic part and the inorganic part constituting the organic-inorganic composite film include a mixed compound of a resin part and an inorganic part. As resin which comprises an organic part, resin illustrated as a constituent material of the resin base material mentioned later can be used, for example. As an inorganic substance which comprises an inorganic part, the inorganic compound illustrated as a material of an inorganic compound film | membrane can be used, for example. Moreover, what shows gas barrier property independently among the things mentioned later as a material of an overcoat layer can be used. Specifically, Clarista CF manufactured by Kuraray Co., Ltd. can be used.

The gas barrier film may be a coating film by coating or the like, or may be a vapor deposition film. Among these, a deposited film is preferable from the viewpoint of high adhesion to a resin base material and high gas barrier performance. The gas barrier film may be a single film formed by a single vapor deposition or a multilayer film formed by a plurality of vapor depositions.
When the gas barrier film is a multilayer film, films having the same composition may be combined, or films having different compositions may be combined. When the gas barrier film is a multi-layer film, the entire multi-layer film is equivalent to one gas barrier film.

The thickness of the gas barrier film is not particularly limited as long as a desired gas barrier property can be exhibited, and can be appropriately set according to the type of the gas barrier film. The thickness of the gas barrier film can be, for example, in the range of 5 nm to 200 nm, and preferably in the range of 10 nm to 100 nm. In addition, when the gas barrier film is a multilayer film, the above thickness means a thickness per one time.
If the thickness of the gas barrier film is less than the above range, film formation may be insufficient and desired gas barrier properties may not be exhibited. In addition, the strength may not be ensured, and deterioration with time may occur. On the other hand, if the thickness of the gas barrier film exceeds the above range, defects may easily occur when subjected to mechanical stress such as bending, and flexibility may be reduced. In addition, when the gas barrier film is composed of a metal film, the preferable thickness is 8 μm or less and 6 μm or less as a preferable thickness from the viewpoint of both flexibility and gas barrier properties, and the preferable range is 1 μm or more. 8 micrometers or less, 2 micrometers or more and 6 micrometers or less are mentioned.

The method for forming the gas barrier film may be any method that can form a film with a desired thickness on one or both sides of the resin base material, and a conventionally known method according to the type of the gas barrier film, such as a coating method, a vapor deposition method, or a pressure bonding method. Can be used.

(Ii) Resin base material The resin base material is not particularly limited as long as it can support the gas barrier film. For example, a resin film or a resin sheet is preferably used. When the resin base material is a resin film, the resin film may be unstretched or uniaxially or biaxially stretched. In the present disclosure, “film” and “sheet” are synonymous.

The resin used for the resin substrate is not particularly limited. For example, a polyolefin resin such as polyethylene or polypropylene; a polyester resin such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polybutylene terephthalate (PBT); a cyclic polyolefin Resin; Polystyrene resin; Acrylonitrile-styrene copolymer (AS resin); Acrylonitrile-butadiene-styrene copolymer (ABS resin); Poly (meth) acrylic resin; Polycarbonate resin; Polyvinyl alcohol (PVA) resin, Ethylene-vinyl alcohol Polyvinyl alcohol resins such as copolymer (EVOH) resins; Polyamide resins such as various nylons; Polyimide resins; Polyurethane resins; Acetal resins; Various resins such as cellulose resins It can be used.

When a plurality of gas barrier films are used for the outer packaging material, it is preferable to use a hydrophilic group-containing resin for the resin base material of the gas barrier film disposed at a position closer to the heat-weldable film. This is because the hydrophilic group-containing resin exhibits a good barrier property against oxygen even at a high temperature, so that the oxygen barrier performance as an outer packaging material can be improved. The “hydrophilic group” refers to an atomic group that forms a weak bond with a water molecule by electrostatic interaction or hydrogen bond, and has an affinity for water, such as a hydroxy group (—OH), An atomic group containing a polar group or a dissociating group such as a carboxy group (—COOH), an amino group (—NH ₂ ), a carbonyl group (> CO), or a sulfo group (—SO ₃ H) shows its properties. Examples of the hydrophilic group-containing resin include natural polymers such as PVA resin, (meth) acrylic resin, cellulose resin, and polysaccharide.

The resin base material may contain various plastic compounding agents and additives. Examples of the additive include a lubricant, a crosslinking agent, an antioxidant, an ultraviolet absorber, a light stabilizer, a filler, a reinforcing agent, an antistatic agent, a pigment, and a modifying resin. The resin base material may be subjected to a surface treatment. This is because the adhesion to the gas barrier film can be improved.

The thickness of the resin substrate is not particularly limited, but can be, for example, in the range of 6 μm to 200 μm, and preferably in the range of 9 μm to 100 μm.

(Iii) Overcoat layer The gas barrier film may have an overcoat layer on the surface of the gas barrier film opposite to the resin substrate. It is because the gas barrier property of the gas barrier film can be further improved by having the overcoat layer.

The material constituting the overcoat layer is not particularly limited, and a material generally used as an overcoat agent can be used. For example, a mixed compound containing an organic portion and an inorganic portion can be used as the main component of the overcoat layer.

There are various kinds of the above mixed compounds. For example, an alumina phosphate mixed compound such as Clarista CF (registered trademark) manufactured by Kuraray Co., Ltd., an acrylic such as Besera (registered trademark) manufactured by Toppan Printing Co., Ltd. A gas barrier resin composition comprising a zinc acid-based mixed compound, a resin and an inorganic layered compound, or a general formula R ¹ _n M (OR ² ) _m (wherein R ¹ and R ² are each having 1 carbon atom) As described above, it represents an organic group of 8 or less, M represents a metal atom, n represents an integer of 0 or more, m represents an integer of 1 or more, and n + m represents the valence of M. One or more alkoxides represented and a water-soluble polymer can be used, and further, a sol-gel compound using a raw material liquid obtained by polycondensation by a sol-gel method can be used. Examples of the water-soluble polymer include polyvinyl alcohol resin, ethylene / vinyl alcohol copolymer, acrylic acid resin, natural polymer methylcellulose, carboxymethylcellulose, cellulose nanofiber, and polysaccharides. In the present disclosure, it is preferable to use a sol-gel compound for the overcoat layer. This is because the sol-gel compound has a high adhesive strength at the interface and can perform the treatment during film formation at a relatively low temperature, thereby suppressing thermal deterioration of the resin base material and the like.

The thickness of the overcoat layer is not particularly limited, but can be, for example, in the range of 50 nm to 500 nm.

(Iv) Others The outer packaging material of the present disclosure has at least two gas barrier films. The number of gas barrier films is not particularly limited, but is preferably in the range of 2 or more and 4 or less, more preferably in the range of 2 or more and 3 or less, particularly 3 sheets. Is preferred. That is, in the present disclosure, it is preferable to have three gas barrier films 2a, 2b, and 2c as shown in FIG. The configuration of each gas barrier film may be the same or different.

In the outer packaging material of the present disclosure, a plurality of gas barrier films are laminated and disposed on one surface side of a heat-weldable film. In the outer packaging material, the order of the resin base material and the gas barrier film in the gas barrier film is not particularly limited, and is appropriately determined according to the layer configuration of each layer other than the gas barrier film, the number of gas barrier films, etc. used together in the outer packaging material. Can be set. Further, when used in a battery, the order of the resin base material and the gas barrier film is not particularly limited in the outermost gas barrier film. For example, as shown in FIG. 1, the resin base material 21 side of the gas barrier film 2b may be disposed so as to face the heat-weldable film 1. Moreover, as shown in FIG. 2, the gas barrier film 22 side of the gas barrier film 2c may be disposed so as to face the heat-weldable film 1.

In the present disclosure, for example, when the gas barrier film 22 is disposed only on one side of the resin base material 21, as shown in FIG. 1, in the gas barrier film 2 a adjacent to the thermally weldable film 1, It is preferable to arrange the resin base material 21 side so as to face the heat-weldable film 1. As shown in FIGS. 1 and 2, the two gas barrier films 2 a and 2 b adjacent to the heat-weldable film 1 are arranged so that the resin base material 21 side faces the heat-weldable film 1. It is preferable. Since the resin base material 21 side is arranged so as to face the heat-weldable film 1, the gas barrier film 22 is arranged on the center side in the thickness direction of the outer packaging material. A gas barrier film 22 is disposed on the opposite side of the heat-weldable film 1 that is easily deformed by heat. For this reason, since the stress applied to the gas barrier film 22 can be suppressed even when the outer packaging material is bent or exposed to heat, the occurrence of cracks in the gas barrier film 22 can be suppressed.

(3) Heat-weldable film The heat-weldable film in the present disclosure can be heat-welded, and is a part that comes into contact with a power generation element when a battery is formed using an outer packaging material. Moreover, it is a site | part which forms the heat welding surface which heat-welds the edge part of the outer packaging materials which oppose.

As a film material that can be thermally welded, a thermoplastic resin is preferable because it can be melted and fused by heating. For example, polyethylene such as linear short-chain branched polyethylene (LLDPE) or unstretched polypropylene ( Polyolefin such as CPP), Polyester such as polyethylene terephthalate (PET), Polyethylene naphthalate (PEN), Polybutylene terephthalate (PBT), Polyamide resins such as polyvinyl acetate, polyvinyl chloride, (meth) acryl, polyurethane, nylon And polyvinyl alcohol such as polyvinyl alcohol (PVA) and ethylene-vinyl alcohol copolymer (EVOH).

In the present disclosure, among the above-described materials, it is preferable that the material of the heat-weldable film is unstretched polypropylene (CPP). This is because unstretched polypropylene (CPP) has high heat resistance and can be used as an outer packaging material having good durability against heat generation from the power generation element. In addition, polypropylene as a raw material for polypropylene film includes a homopolymer produced using a single monomer and a copolymer produced using two or more monomers. The above-mentioned copolymers can be further classified according to the sequence of the monomers, and include random copolymers having no order in the sequence of monomers and block copolymers having a sequence in which the same type of monomers are continuously long. In the present disclosure, unstretched polypropylene made of a homopolymer is preferred. This is because an unstretched polypropylene film made of a homopolymer has a high indentation elastic modulus and good pinhole resistance of the outer packaging material.

Further, acid-modified polyolefin may be used as a material for the film that can be heat-welded. The acid-modified polyolefin is a polymer obtained by modifying the above polyolefin by block polymerization or graft polymerization with carboxylic acid or the like. Examples of the carboxylic acid used for modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, itaconic anhydride and the like.

The melting temperature (melting point) of the heat-weldable film is preferably, for example, in the range of 80 ° C. or higher and 300 ° C. or lower, and more preferably in the range of 100 ° C. or higher and 250 ° C. or lower. If the melting temperature of the heat-weldable film is too low, the sealing surface of the outer packaging material may peel off under the usage environment of the battery formed using the outer packaging material of the present disclosure. In addition, if the melting temperature of the heat-weldable film is too high, the outer packaging material needs to be heat-welded at a high temperature, so that the gas barrier film or the like used together as the outer packaging material may be deteriorated by heat.

The thickness of the heat-weldable film is not particularly limited, and is preferably in the range of 15 μm or more and 100 μm or less, for example. When the thickness of the heat-weldable film is larger than the above range, the gas barrier property of the outer packaging material may be deteriorated. When the thickness is smaller than the above range, a desired adhesive force cannot be obtained. There is. The thickness of the heat-weldable film is more preferably in the range of 25 μm or more and 90 μm or less, and further preferably in the range of 30 μm or more and 80 μm or less.

The heat-weldable film in the present disclosure preferably has an indentation elastic modulus within a predetermined range. Specifically, the indentation elastic modulus of the heat-weldable film is preferably 0.5 GPa or more and 5 GPa or less, more preferably 0.5 GPa or more and 4.5 GPa or less, and 0.5 GPa or more and 1.2 GPa or less. More preferably, it is as follows. Moreover, it is also preferable that it is 1.0 GPa or more and 4.5 GPa or less.
This is because if the indentation elastic modulus of the heat-weldable film is too low, stress concentration tends to occur on the gas barrier film and the gas barrier film may be easily broken when the outer packaging material is bent. On the other hand, if the indentation elastic modulus is too high, a film that can be thermally welded may be easily broken due to stress concentration when the outer packaging material is bent. Moreover, it is because the flexibility of an outer packaging material may fall.
In this indication, it can be set as an outer packaging material with favorable pinhole resistance by making the indentation elastic modulus of the film which can be heat-sealed into the range mentioned above.

In particular, when the heat-weldable film is a polypropylene film (such as an unstretched polypropylene film), the indentation elastic modulus is preferably 0.8 GPa or more, and more preferably 0.8 GPa or more and 5.0 GPa or less. 1.0 GPa or more and 4.0 GPa or less is more preferable. When the heat-weldable film is a polyethylene film, the indentation elastic modulus is preferably 1.0 GPa or less, more preferably 0.2 GPa or more and 1.0 GPa or less, and 0.3 GPa or more and 0.0. More preferably, it is 8 GPa or less. The reason why the preferable indentation elastic modulus varies depending on the type of resin constituting the heat-weldable film is, for example, when using a polypropylene film such as an unstretched polypropylene film, the indentation elastic modulus of the heat-welded layer is set to the above value. As a result, the rigidity of the entire outer packaging material is increased, and the bending resistance is improved. On the other hand, in the case of a polyethylene film, by setting the indentation elastic modulus to the above value, the flexibility of the entire outer packaging material is enhanced and the bending resistance is improved.

The indentation elastic modulus is measured in accordance with ISO 14577: 2015, and a Vickers indenter (a square pyramid diamond indenter with a face angle of 136 °) is attached to the cross section of the sample in an environment of about 23 ° C. and about 60% RH. A method of measuring indentation elastic modulus using an ultra-micro load hardness tester. The measurement is performed at an indentation speed of 0.1 μm / second, an indentation depth of 2 μm, a holding time of 5 seconds, and an extraction speed of 0.1 μm / second. Picodenter HM500 (manufactured by Fischer Instruments) is preferable as the ultra micro load hardness tester. In one condition, at least five samples are measured, and the average of the measured values is used as the value of the indentation elastic modulus of the condition. The cross section of the sample is a cross section where the outer periphery of the sample is fixed by fixing with a cured resin adhesive, the fixed sample is cut in the thickness direction with a diamond knife, and the sample is exposed.
Moreover, the thickness of each film at the time of calculating the indentation elasticity index can be measured by measuring the cut section with an optical microscope.

(4) Protective film The outer packaging material of this indication may have a protective film other than the heat-weldable film and gas barrier film mentioned above. It is because each film used together as an outer packaging material, such as a heat-weldable film and a gas barrier film, can be protected from damage and deterioration by having the protective film as a protective film. The protective film can be distinguished from the above-described films in that no layer having a gas barrier property is disposed on either side of the protective film. Although the arrangement position in the outer packaging material of the protective film is not particularly limited, it is preferably arranged on the surface side opposite to the heat-weldable film of the gas barrier film, and when forming the battery, the outermost layer ( It is more preferable that a protective film is disposed at a position to be the outermost layer.

As the protective film, it is preferable to use a resin having a higher melting point than the heat-weldable film, and it may be in the form of a sheet or film. As such a protective film, for example, nylon, polyester, polyamide, polypropylene, polyurethane, amino resin, silicone resin, epoxy resin, thermosetting resin such as polyimide (PI), polyvinyl chloride (PVC), polycarbonate (PC) , Polystyrene (PS), polyvinyl alcohol (PVA), ethylene / vinyl acetate copolymer (EVAL), polyacrylonitrile (PAN), cellulose nanofiber (CNF), etc. ), Polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), expanded polypropylene (OPP), polyvinyl chloride (PVC) and the like are preferably used.

The protective film may be a single layer, or may be a multilayer formed by laminating layers made of the same material or layers made of different materials. The protective film may be subjected to a surface treatment such as a corona discharge treatment from the viewpoint of improving the adhesion with other layers. The thickness of the protective film is not particularly limited, but is generally in the range of 5 μm or more and 80 μm or less.

The protective film may contain other materials such as an anti-blocking agent, a lubricant, a flame retardant, and a filler. These materials can be composed of inorganic compounds. Alternatively, a hard coat layer containing an inorganic compound may be formed.

2. Characteristics of outer packaging material The outer packaging material of the present disclosure has a gas barrier property that can suppress deterioration of the power generation element due to air. Outer cover material of the present disclosure, the oxygen permeability of ^{0.5cc / (m 2 · 24h ·} atm) or less, preferably ^{0.1cc / (m 2 · 24h ·} atm) or less, particularly 0.05cc / (m ² · 24h -Preferably atm) or less. Further, the outer packaging material of the present disclosure has a water vapor permeability of 0.5 g / (m ² · 24 h) or less, preferably 0.1 g / (m ² · 24 h) or less, particularly 0.05 g / (m ² · 24h) or less. This is because the power generation element can be satisfactorily sealed by having the gas barrier property within the above-described range.

Oxygen permeability is measured according to JIS K7126-2: 2006 (Plastics-Film and sheet-Gas permeability test method-Part 2: Isobaric method, Appendix A: Test method of oxygen gas permeability by electrolytic sensor method) In conformity, it can be measured using an oxygen gas permeability measuring device under conditions of a temperature of 23 ° C. and a humidity of 60% RH. As an oxygen gas permeability measuring device, for example, OXTRAN manufactured by MOCON, USA can be used. The measurement is carried out by mounting in the apparatus such that the surface located on the gas barrier film side is in contact with oxygen gas with respect to the film that can be heat-welded in the thickness direction of the outer packaging material among the surfaces of the outer packaging material. It is performed under the condition of 50 cm ² . The said measurement is performed in the following procedures. First, the carrier gas is purged by supplying the carrier gas at a flow rate of 10 cc / min for 60 minutes or more. As the carrier gas, nitrogen gas containing about 5% hydrogen can be used. After purging, the test gas is allowed to flow through the apparatus, and after 12 hours have been secured as the time from the start of flowing until the equilibrium state is reached, the measurement is started under the temperature and humidity conditions described above. The test gas is dry oxygen containing at least 99.5% (volume) oxygen. In one condition, at least three samples are measured, and the average of the measured values is taken as the oxygen permeability value for that condition. The oxygen permeability described in this specification can be measured using the same method as described above.

The water vapor transmission rate is measured at a temperature of 40 ° C. in accordance with JIS K7129-B: 2008 (Plastics-Films and Sheets—Method of obtaining water vapor transmission rate (instrument measurement method), Appendix B: Infrared sensor method). Under the condition of 90% RH (Condition 3), using the water vapor permeability measuring device, the outer side of the outer packaging material (the side where the gas barrier film of the heat-weldable film is disposed) is the high humidity side (the water vapor supply side) Thus, a measurement method is used under the condition of a transmission area of 50 cm ² . The water vapor permeability measuring device is preferably Permatran (PERMATRAN-W (registered trademark) Model 3/33, manufactured by MOCON, an American company). NIST film # 3 is used as a standard test piece. Under one condition, at least three samples are measured, and the average of the measured values is taken as the value of the water vapor permeability of the condition. The oxygen permeability described in this specification can be measured using the same method as described above.

In the present disclosure, the ash content of the outer packaging material may be 1.0% by mass or more and 20.0% by mass or less, may be 1.0% by mass or more and 16.0% by mass or less, 1.0 mass% or more and 15.0 mass% or less may be sufficient, and also in the range of 1.0 mass% or more and 5.0 mass% or less may be sufficient. The ash content of the outer packaging material approximates the content of the inorganic compound component in the entire outer packaging material. In general, inorganic compounds are more fragile than organic compounds and are more likely to have defects than organic compounds when subjected to the same stress. As the content of the inorganic compound component in the entire outer packaging material is larger, fine defects tend to occur more easily. In the present disclosure, since the ash content of the outer packaging material is in the above range, generation of minute defects when bent can be particularly suppressed.

In addition, regarding the ease of generation of minute defects when bent due to the inorganic compound, for example, it is conceivable to specify the thickness of each film or layer in which the inorganic compound is used. Examples of the inorganic compound component contained in the outer packaging material include a gas barrier film of a gas barrier film. However, as the gas barrier film, a film formed by various methods such as foil, vapor deposition, or coating is appropriately used. Moreover, in vapor deposition and application | coating, the density of the film | membrane obtained, for example according to formation conditions differs, and an organic compound component may be contained in a film | membrane. For this reason, it is difficult to evaluate the ease of occurrence of minute defects when bent only by the thickness of the gas barrier film. In addition, it is difficult to determine the content of the inorganic compound component only from the thickness of the gas barrier film. Furthermore, an inorganic compound component may be contained for various purposes in a resin substrate, a heat-weldable film, an adhesive layer, and the like, and the influence of the inorganic compound component needs to be considered. However, as with the gas barrier film, there are various methods for forming these films and layers, their conditions, and raw materials. Therefore, it is easy to generate microscopic defects when folded by only their thickness. Is difficult to evaluate. The ash content of the outer packaging material is, for example, a usage mode of an inorganic compound, such as a case where an inorganic compound is used in a configuration other than a gas barrier film such as a resin base material, a heat-weldable film, a protective film, or an adhesive layer. Is complicated, it has a great advantage as a comprehensive indicator of the occurrence of minute defects when bent.

Ash content is to examine the proportion of non-flammable inorganic compounds remaining after the outer packaging material burns out in the mass of the entire outer packaging material. In the present disclosure, the mass of the measurement sample is measured using a thermogravimetric / differential thermal analyzer (TG-DTA) and then heated in an aluminum pan and in an air atmosphere at a heating rate of 10 ° C./min. After the temperature is raised from room temperature to 600 ° C., the measurement sample is incinerated by heating at 600 ° C. for 30 minutes as it is, and the value obtained by expressing the mass after heating with respect to the mass before heating as a percentage is defined as ash. As the thermogravimetric / differential thermal simultaneous analyzer at this time, TG8120 manufactured by Rigaku Corporation can be used.

3. Other Examples of the manufacturing method of the outer packaging material of the present disclosure include, for example, a dry lamination process in which each film formed in advance is bonded using an adhesive, each material of a gas barrier film that has been thermally melted, a T-die, and the like. It can be used by extruding and laminating, and laminating a film that can be heat-welded via an adhesive to the obtained laminate.

Note that the present disclosure is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has the same configuration as the technical idea described in the claims of the present disclosure and has the same function and effect regardless of the present embodiment. It is included in the technical scope of the disclosure.

Hereinafter, the present disclosure will be described more specifically with reference to examples and comparative examples.

The abbreviations of the films used in the production of the outer packaging material are as follows. Details of each film are shown in Table 1.
Al-deposited PET12: Polyethylene terephthalate (PET) film (thickness 12 μm) with an aluminum (Al) film (thickness 55 nm) deposited on one side
・ Al vapor deposition EVOH15: An ethylene-vinyl alcohol copolymer (EVOH) film (thickness 15 μm) having an aluminum (Al) film (thickness 55 nm) deposited on one side
・ SiO ₂ deposition ON15: Nylon film (thickness 15 μm) with a silicon dioxide (SiO ₂ ) film (thickness 10 nm) deposited on one side
Barrier PET12: Polyethylene terephthalate (PET) film (thickness: 12 μm) having a barrier coat layer (hereinafter referred to as Al ₂ O ₃ + P-based coat layer) having a mixed composition of aluminum oxide and phosphoric acid on one surface
CPP20: unstretched polypropylene film (thickness 20 μm)
CPP40: unstretched polypropylene film (thickness 40 μm)
LLDPE50: linear short chain branched polyethylene film (thickness 50 μm)
PET12: Biaxially stretched polyethylene terephthalate film (thickness 12 μm)
ON15: Biaxially stretched nylon film (thickness 15 μm)
・ Al40: Aluminum foil (thickness 40 μm)
CPP80: unstretched polypropylene film (thickness 80 μm)
ON25: biaxially stretched nylon film (thickness 25 μm)
Al-deposited PET12-2: Polyethylene terephthalate (PET) film (thickness 12 μm) with an aluminum (Al) film (thickness 35 nm) deposited on one side
Al vapor deposition EVOH12: An ethylene-vinyl alcohol copolymer (EVOH) film (thickness 12 μm) in which an aluminum (Al) film (thickness 55 nm) is vapor-deposited on one side
LLDPE30: linear short chain branched polyethylene film (thickness 30 μm)

[Example 1]
(Preparation of adhesive)
An acid-modified polypropylene having a solid content of 20% by mass and a melting temperature (melting point) of 50 ° C. was prepared as the main agent. Moreover, solid content is 10 mass% as a hardening | curing agent, and the weight average molecular weight 500 epoxy resin was prepared. The weight average molecular weight was 3 by using “Waters, Alliance 2695” as a gel permeation chromatography (GPC) measurement, and “Shodex GPC LF-804 (Showa Denko, 8.0 mm ID × 300 mm)” as a column. This was measured using THF (tetrahydrofuran) as an eluent. As experimental conditions, the experiment was conducted using a sample concentration of 0.5%, a flow rate of 1.0 ml / min, a sample injection amount of 50 μl, a measurement temperature of 40 ° C., and an RI detector. The calibration curve was prepared from “polystyrene standard sample TSK standard” manufactured by Tosoh Corporation.
10 parts by weight of acid-modified polypropylene and 0.5 parts by weight of epoxy resin were mixed to obtain an adhesive.

(Production of outer packaging material)
An outer packaging material was obtained by laminating CPP ₂₀ as a heat welding film, Al vapor-deposited PET 12 as a first gas barrier film, Al vapor-deposited PET 12 as a second gas barrier film, and SiO ₂ vapor-deposited ON 15 as a third gas barrier film in this order. The first gas barrier film and the second gas barrier film are arranged so that the PET film side of the first gas barrier film faces the Al vapor deposition film side of the second gas barrier film, and the third gas barrier film is composed of the SiO ₂ vapor deposition film. The film was placed so as to face the heat-weldable film side.
The adhesive layer was arrange | positioned between each film layer using the adhesive agent mentioned above, and each film was joined by the adhesive layer.
The specific joining method of each film is as follows. Of the two films arranged adjacent to each other in the outer packaging material, the adhesive described above was applied to one film so that the applied amount was 1.5 g / m ² to form an adhesive layer. Next, the film was joined by pressing the film on which the adhesive layer was disposed and the other film with the adhesive layer interposed therebetween.
The outer packaging material was obtained by the above procedure.

[Example 2]
An outer packaging material was obtained by laminating LLDPE50 as a heat-welded film, Al-deposited PET12 as a first gas barrier film, Al-deposited PET12 as a second gas barrier film, and barrier PET12 as a third gas barrier film in this order. The orientation of the resin base material and the gas barrier film of each gas barrier film is the same as in Example 1.
As the adhesive, the two-component curable adhesive described in Example 1 was applied so that the application amount was 1.5 g / m ² , the adhesive layer was disposed, and the respective films were joined. The outer packaging material was obtained by the above procedure.

[Comparative Example 1]
(Preparation of adhesive)
A main component (product name: RU-77T, manufactured by Rock Paint Co., Ltd.) mainly composed of polyester polyol, a curing agent containing an aliphatic polyisocyanate (product name: H-7 manufactured by Rock Paint Co., Ltd.), and a solvent of ethyl acetate. A two-pack curable adhesive was prepared in which the weight ratio was main agent: curing agent: solvent = 10: 1: 14.

(Production of outer packaging material)
An outer packaging material was obtained by laminating LLDPE50 as a heat-welded film, Al-deposited EVOH15 as a first gas barrier film, Al-deposited PET12 as a second gas barrier film, and barrier PET12 as a third gas barrier film in this order. The first gas barrier film and the second gas barrier film are arranged so that the Al vapor deposition film side of the first gas barrier film faces the Al vapor deposition film side of the second gas barrier film, and the gas barrier film is heated by the third gas barrier film. It arranged so that the film side which can be welded faced.
As the adhesive, the two-component curable adhesive described above was applied so that the application amount was 3.5 g / m ² , an adhesive layer was disposed, and each film was bonded in the same manner as in Example 1. The outer packaging material was obtained by the above procedure.

[Comparative Example 2]
An outer packaging material was obtained by laminating CPP 40 as the heat welding film, Al vapor-deposited PET 12 as the first gas barrier film, Al vapor-deposited PET 12 as the second gas barrier film, and SiO ₂ vapor-deposited ON 15 as the third gas barrier film in this order. The directions of the resin base material and the gas barrier film of each gas barrier film are the same as in Comparative Example 1.
As the adhesive, the two-component curable adhesive described in Comparative Example 1 was applied so that the application amount was 3.5 g / m ² , an adhesive layer was disposed, and each film was joined in the same manner as in Example 1. . The outer packaging material was obtained by the above procedure.

[Comparative Example 3]
An outer packaging material was obtained by laminating CPP80 as a heat welding film, Al40 as a first gas barrier film, ON15 as a first protective film, and PET12 as a second protective film in this order.
As the adhesive, the two-component curable adhesive described in Comparative Example 1 was applied so that the application amount was 3.5 g / m ² , an adhesive layer was disposed, and each film was joined in the same manner as in Example 1. . The outer packaging material was obtained by the above procedure.

[Comparative Example 4]
An outer packaging material was obtained by laminating CPP 40 as the heat-welded film, Al-deposited PET12 as the first gas barrier film, Al-deposited PET12 as the second gas barrier film, and Al-deposited PET12 as the third gas barrier film in this order. The directions of the resin base material and the gas barrier film of each gas barrier film are the same as in Comparative Example 1.
As the adhesive, the two-component curable adhesive described in Comparative Example 1 was applied so that the application amount was 3.5 g / m ² , an adhesive layer was disposed, and each film was joined in the same manner as in Example 1. . The outer packaging material was obtained by the above procedure.

[Comparative Example 5]
An outer packaging material was obtained by laminating CPP ₂₀ as a heat welding film, Al vapor-deposited PET 12 as a first gas barrier film, Al vapor-deposited PET 12 as a second gas barrier film, and SiO ₂ vapor-deposited ON 15 as a third gas barrier film in this order. The directions of the resin base material and the gas barrier film of each gas barrier film are the same as in Comparative Example 1.
As the adhesive, the two-component curable adhesive described in Comparative Example 1 was applied so that the application amount was 3.5 g / m ² , an adhesive layer was disposed, and each film was joined in the same manner as in Example 1. . The outer packaging material was obtained by the above procedure.

[Comparative Example 6]
An outer packaging material was obtained by laminating LLDPE50 as a heat-welded film, Al-deposited EVOH12 as a first gas barrier film, Al-deposited PET12-2 as a second gas barrier film, and ON25 as a first protective film in this order. The directions of the resin base material and the gas barrier film of each gas barrier film are the same as in Comparative Example 1.
As the adhesive, the two-component curable adhesive described in Comparative Example 1 was applied so that the application amount was 3.5 g / m ² , an adhesive layer was disposed, and each film was joined in the same manner as in Example 1. . The outer packaging material was obtained by the above procedure.

[Comparative Example 7]
LLDPE30 as a heat-bonding film, Al vapor-deposited PET12 as a first gas barrier film, barrier PET12 as a second gas barrier film, barrier PET12 as a third gas barrier film, and barrier PET12 as a fourth gas barrier film are laminated in this order to enclose I got the material. The first gas barrier film and the second gas barrier film are arranged so that the Al vapor deposition film side of the first gas barrier film and the barrier coat layer of the second gas barrier film face each other, and the third gas barrier film and the fourth gas barrier film are respectively The barrier coat layer was disposed so as to face the heat-weldable film side.
Each film was the same as in Example 1 except that the two-component curable adhesive described in Comparative Example 1 was applied as an adhesive so that the applied amount was 3.5 g / m ² and an adhesive layer was disposed. Were joined. The outer packaging material was obtained by the above procedure.

The structure of the outer packaging material of Examples and Comparative Examples 1 to 7 is shown. In addition, the “configuration of the outer packaging material” in Table 2 indicates the overlapping order of the films, and the description of the adhesive layer disposed between the films is omitted. In Table 2, “/” indicates the interface of each film.

[Evaluation]
(Electrolytic solution resistance)
Each outer packaging material was subjected to an electrolyte resistance test, and the peel strength between the heat-welded film and the barrier film before and after the test was measured.
The conditions for thermal welding at the time of producing the bag-shaped outer packaging material were a temperature of 190 ° C., a surface pressure of 1.0 MPa, and a heating / pressurizing time of 3 seconds. The electrolytic solution was obtained by mixing lithium hexafluorophosphate with a solution mixed at a volume ratio of ethylene carbonate: diethyl carbonate: dimethyl carbonate = 1: 1: 1. The electrolytic solution resistance test and the peel strength measurement conditions are as described in the above-mentioned section “1. Configuration of outer packaging material (1) Adhesive layer”. The results are shown in Table 3.

As shown in Table 3, in Comparative Example 3, since Al40 (aluminum foil having a thickness of 40 μm) is used as the gas barrier film, resistance to electrolytic solution is hardly lowered due to dissolution of the gas barrier film in the electrolytic solution. In addition, the retention rate (the tensile rupture strength after the test ÷ the tensile rupture strength before the test × 100) with respect to the initial value of the peel strength shows a high value. In contrast, as in Comparative Examples 1 to 2 and 4 to 7, the use of the laminate of the Al deposition PET 12, Al deposition EVOH15, gas barrier film and the resin base material such as SiO ₂ deposition ON15 as a gas barrier film, Since Al vapor deposition which constitutes the gas barrier film is easily dissolved in the electrolytic solution, the problem of improving the electrolytic solution resistance of the outer packaging material becomes remarkable. However, in Examples 1 and 2, since the adhesive layer is formed using an adhesive excellent in electrolytic solution resistance, it can be seen that this problem has been suitably solved.

(Water vapor permeability)
The water vapor permeability at 40 ° C. and 90% RH in the outer packaging materials of Examples and Comparative Examples 1 to 7 was measured. The details of the measuring method are as described in the section “2. Characteristics of the outer packaging material”. The results are shown in Table 4.

(Oxygen permeability)
The oxygen permeability of 23 ° C. and 60% RH in the outer packaging materials of Examples and Comparative Examples 1 to 7 was measured. The details of the measuring method are as described in the section “2. Characteristics of the outer packaging material”. The results are shown in Table 4.

(Flexibility evaluation)
The flexibility of the outer packaging materials of Examples and Comparative Examples 1 to 7 was evaluated. The details of the evaluation method are as described above in the section “The outer packaging material has flexibility”. The results are shown in Table 4.

(Ashes evaluation)
The ash content of the outer packaging materials of Examples and Comparative Examples 1 to 7 was evaluated. The details of the evaluation method are as described in the section “2. Characteristics of the outer packaging material”. The results are shown in Table 4.

(Indentation modulus of heat-weldable film)
The indentation elastic modulus of the heat-weldable films of the outer packaging materials of Examples and Comparative Examples 1 to 7 was measured. The details of the measurement method are as described in the section of “1. Structure of outer packaging material (3) Film capable of being thermally welded”. The results are shown in Table 4.

As is apparent from the results shown in Table 4, the outer packaging materials of Examples 1 and 2 have a water vapor permeability of 0.5 g / (m ² · 24 h) or less of the test piece after the third bending treatment, and The oxygen permeability is 0.5 cc / (m ² · 24 h · atm) or less, and further satisfies the relationship of tensile modulus × (thickness) ³ <1.0. Therefore, it can be seen that the outer packaging materials of Examples 1 and 2 have excellent flexibility. In contrast, in the outer packaging material of Comparative Example 3, the oxygen permeability of the test piece after the third bending treatment exceeds 0.5 cc / (m ² · 24 h · atm). In the outer packaging material of Comparative Example 4, the water vapor permeability of the test piece after the third bending treatment exceeds 0.5 g / (m ² · 24 h), and the oxygen permeability is 0.5 cc / (m ² · 24h · atm). Further, in the outer packaging materials of Comparative Examples 6 and 7, the water vapor permeability of the test piece after the third bending treatment exceeds 0.5 g / (m ² · 24 h). For this reason, it turns out that these outer packaging materials do not have suitable flexibility compared with Examples 1 and 2. In Comparative Examples 1 to 4, 6 to 7, the outer packaging material does not satisfy the relationship of tensile elastic modulus × (thickness) ³ <1.0. It can be seen that it does not have suitable flexibility.

DESCRIPTION OF SYMBOLS 1 ... Heat-weldable film 2, 2a, 2b, 2c ... Gas barrier film 3, 3a, 3b, 3c ... Adhesive layer 10 ... Battery outer packaging material 21 ... Resin base material 22 ... Gas barrier film

Claims (12)

A battery outer packaging material having a plurality of flexible films,
A heat-weldable film, a plurality of gas barrier films disposed on one side of the heat-weldable film, and a plurality of adhesive layers disposed between the plurality of films,
The gas barrier film has a resin base material and a gas barrier film disposed on one or both surfaces of the resin base material and containing an inorganic substance.
An outer packaging material for a battery, wherein an adhesive layer disposed between at least the heat-weldable film and the gas barrier film among the plurality of adhesive layers has an electrolytic solution resistance. A battery outer packaging material in which a plurality of films are laminated,
A heat-weldable film, a plurality of gas barrier films disposed on one side of the heat-weldable film, and a plurality of adhesive layers disposed between the plurality of films,
The gas barrier film has a resin base material and a gas barrier film disposed on one or both surfaces of the resin base material and containing an inorganic substance.
Among the plurality of adhesive layers, at least the adhesive layer disposed between the heat-weldable film and the gas barrier film has an electrolyte resistance,
The battery outer packaging material satisfies the relationship of tensile elastic modulus (MPa) × (thickness (mm)) ³ <1.0 (MPa · mm ³ ). The battery outer packaging material according to claim 1, wherein all of the plurality of adhesive layers have resistance to an electrolytic solution. The adhesive layer having resistance to electrolytic solution is a cured product of a resin composition containing at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and a compound having an epoxy group. The outer packaging material for a battery according to any one of claims 1 to 3. Curing of a resin composition comprising a curing agent in which the adhesive layer having resistance to electrolytic solution has at least one selected from the group consisting of an oxygen atom, a heterocyclic ring, a C═N bond, and a C—O—C bond. The battery outer packaging material according to any one of claims 1 to 3, which is a product. The said adhesion layer which has electrolyte solution resistance contains at least 1 sort (s) selected from the group which consists of a urethane resin, ester resin, and an epoxy resin, The claim in any one of Claim 1 to 3 Battery outer packaging material. The outer packaging material for a battery according to any one of claims 1 to 6, wherein the water vapor permeability in an atmosphere of temperature 40 ° C and humidity 90% RH is 0.1 g / (m ² · 24h) or less. . The battery outer packaging material according to any one of claims 1 to 7, wherein an indentation elastic modulus of the heat-weldable film is 0.5 GPa or more. The battery outer packaging material according to any one of claims 1 to 8, wherein an ash content measured by the following method is 1.0 mass% or more and 20.0 mass% or less.
(Measurement method of ash)
After measuring the mass of the measurement sample using a thermogravimetric / differential thermal analyzer, the temperature was raised from room temperature to 600 ° C. at a rate of temperature rise of 10 ° C./min in an aluminum pan and in an air atmosphere. The measurement sample is ashed by heating at 600 ° C. for 30 minutes, and the value obtained by expressing the mass after heating with respect to the mass before heating as a percentage is defined as ash. A battery in which a battery element including at least a positive electrode, a negative electrode, and an electrolyte is accommodated in a package formed by the battery outer packaging material according to any one of claims 1 to 9. A method for producing an outer packaging material for a battery having flexibility and a plurality of films laminated,
A step of laminating a heat-weldable film, a plurality of gas barrier films, and a plurality of adhesive layers;
The plurality of gas barrier films are arranged by laminating on one surface side of the thermally weldable film,
The plurality of adhesive layers are disposed between the plurality of films,
The gas barrier film has a resin base material and a gas barrier film disposed on one or both surfaces of the resin base material and containing an inorganic substance.
The manufacturing method of the outer packaging material for batteries by which the contact bonding layer arrange | positioned between the film which can be heat-welded among the several contact bonding layers, and the said gas barrier film has electrolyte solution resistance. A method for producing a battery outer packaging material in which a plurality of films are laminated,
A step of laminating a heat-weldable film, a plurality of gas barrier films, and a plurality of adhesive layers;
The plurality of gas barrier films are arranged by laminating on one surface side of the thermally weldable film,
The plurality of adhesive layers are disposed between the plurality of films,
The gas barrier film has a resin base material and a gas barrier film disposed on one or both surfaces of the resin base material and containing an inorganic substance.
Among the plurality of adhesive layers, at least the adhesive layer disposed between the heat-weldable film and the gas barrier film has an electrolyte resistance,
The battery outer packaging material satisfies the relationship of tensile elastic modulus (MPa) × (thickness (mm)) ³ <1.0 (MPa · mm ³ ).

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