WO2018066672A1

WO2018066672A1 - Packaging material for battery, manufacturing method therefor, and battery

Info

Publication number: WO2018066672A1
Application number: PCT/JP2017/036386
Authority: WO
Inventors: かおる津森; 山下　力也; 山下　孝典
Original assignee: 大日本印刷株式会社
Priority date: 2016-10-05
Filing date: 2017-10-05
Publication date: 2018-04-12
Also published as: JPWO2018066672A1; JP7151484B2; CN109964333B; CN109964333A

Abstract

Provided is a packaging material for a battery, said packaging material being highly insulating and durable. A packaging material for a battery, said packaging material being composed from a layered body that comprises at least a substrate layer, a barrier layer, a curable resin layer, and a thermally fusible resin layer, in this order, wherein according to a thermomechanical analysis that measures the amount of displacement of a probe, where the probe is positioned on a surface of the curable resin layer in a cross-section of the layered body, the measured value of deflection of the probe at the start of measurement is -4V, and the temperature increase speed is 5°C/min, when the probe is heated under these conditions from 40°C to 220°C, the location of the probe does not fall below an initial value.

Description

Battery packaging material, manufacturing method thereof and battery

The present invention relates to a battery packaging material, a method for producing the same, and a battery.

Conventionally, various types of batteries have been developed. In these batteries, a battery element composed of an electrode, an electrolyte and the like needs to be sealed with a packaging material or the like. Metal packaging materials are frequently used as battery packaging materials.

In recent years, batteries having various shapes have been demanded with the improvement in performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones and the like. The battery is also required to be thin and light. However, it is difficult to follow the diversification of battery shapes with metal packaging materials that have been widely used in the past. Further, since it is made of metal, there is a limit to reducing the weight of the packaging material.

Therefore, as a battery packaging material that can be easily processed into various shapes and can be made thinner and lighter, there is a film-like laminate in which a base material layer / barrier layer / heat-sealable resin layer are sequentially laminated. Proposed.

Patent Document 1 includes a base material layer, an adhesive layer, an aluminum foil layer provided with a corrosion prevention treatment layer, an adhesive resin layer, a sealant layer provided on the opposite side of the adhesive resin layer to the base material layer, and Are sequentially laminated, and an exterior material for a lithium ion battery in which an adhesive resin layer contains an acid-modified polyolefin resin and an elastomer is disclosed.

JP 2013-258162 A

However, as a result of intensive studies by the inventor, in the battery packaging material disclosed in Patent Document 1, when the battery packaging material is applied to a battery, the insulation and durability may be reduced. The problem was found.

Therefore, as a result of further earnest studies by the present inventors, in the battery manufacturing process, there may be cases where minute foreign matters such as electrode active material and electrode tab fragments adhere to the surface of the heat-fusible resin layer, It has been clarified that the portion of the heat-fusible resin layer to which foreign matter has adhered may become thin depending on the heat and pressure when the battery element is heat-sealed with the battery packaging material. For example, there is a problem that the insulation and durability of the battery packaging material may be insufficient when the heat-fusible resin layer becomes thin in a portion where the heat-fusible resin layers are heat-sealed. is there.

Furthermore, minute foreign matters such as electrode active material and electrode tab fragments have electrical conductivity. When conductive foreign matter exists between the electrode tab and the heat-fusible resin layer, if the foreign matter penetrates the heat-fusible resin layer due to heat and pressure during heat sealing, the electrode tab and battery The barrier layer of the packaging material may be electrically connected to cause a short circuit.

The present invention has been made in view of these problems. That is, the main object of the present invention is to provide a battery packaging material having high insulation and durability.

The present inventor has intensively studied to solve the above problems. As a result, a thermomechanical analysis in which the battery packaging material is constituted by a laminate including a base material layer, a barrier layer, a cured resin layer, and a heat-fusible resin layer in this order, and measures the displacement of the probe. In the above, a probe is set on the surface of the cured resin layer in the cross section of the battery packaging material (the laminate), the deflection setting value of the probe at the start of measurement is −4 V, and the temperature rising rate is 5 ° C./min. It was found that when the probe was heated from 40 ° C. to 220 ° C. under the conditions, the position of the probe did not fall below the initial value, and thus a battery packaging material having high insulation and durability could be obtained.

The present invention has been completed by further studies based on these findings. That is, this invention provides the invention of the aspect hung up below.
Item 1. It is composed of a laminate including at least a base material layer, a barrier layer, a cured resin layer, and a heat-fusible resin layer in this order,
In the thermomechanical analysis for measuring the displacement of the probe, the probe is set on the surface of the cured resin layer in the cross section of the laminate, and the set value of the deflection of the probe at the start of the measurement is −4 V, the heating rate is 5 A battery packaging material in which, when the probe is heated from 40 ° C. to 220 ° C. under the condition of ° C./min, the position of the probe does not fall below the initial value.
Item 2. In the thermomechanical analysis for measuring the displacement of the probe, the probe is set on the surface of the cured resin layer in the cross section of the laminate, and the set value of the deflection of the probe at the start of the measurement is −4 V, the heating rate is 5 When the probe was heated from 40 ° C. to 220 ° C. under the condition of ° C./min, the amount of increase in the position of the probe when heated from 140 ° C. to 220 ° C. was when heated from 80 ° C. to 120 ° C. Item 2. The battery packaging material according to Item 1, wherein the battery packaging material is larger than the amount of increase in the position of the probe.
Item 3. Item 3. The battery packaging material according to

Item

1 or 2, wherein the cured resin layer is a cured product of a resin composition containing an acid-modified polyolefin.
Item 4. The acid-modified polyolefin of the cured resin layer is maleic anhydride-modified polypropylene,
Item 4. The battery packaging material according to Item 3, wherein the heat-fusible resin layer contains polypropylene.
Item 5. Item 5. The battery packaging material according to any one of Items 1 to 4, wherein the resin constituting the cured resin layer contains a polyolefin skeleton.
Item 6. Item 5. The cured resin layer 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, an epoxy resin, and a urethane resin. The battery packaging material according to any one of the above.
Item 7. The cured resin layer is a cured product of a resin composition containing a curing agent having 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 packaging material according to any one of 1 to 6.
Item 8. Item 7. The battery packaging material according to any one of Items 1 to 6, wherein the cured resin layer contains at least one selected from the group consisting of urethane resins, ester resins, and epoxy resins.
Item 9. Item 9. The battery packaging material according to any one of Items 1 to 8, wherein the thickness of the cured resin layer is 0.6 μm or more and 11 μm or less.
Item 10. Item 10. The battery packaging material according to any one of Items 1 to 9, wherein a softening temperature of the cured resin layer is in a range of 180 ° C. or higher and 260 ° C. or lower.
Item 11. Item 11. The battery packaging material according to any one of Items 1 to 10, wherein the thickness of the heat-fusible resin layer is in the range of 10 μm to 40 μm.
Item 12. Item 12. The battery packaging material according to any one of Items 1 to 11, wherein the heat-fusible resin layer has fine irregularities on the surface thereof.
Item 13. At least a layering step of obtaining a laminate including a base material layer, a barrier layer, a cured resin layer, and a heat-fusible resin layer in this order;
In the thermomechanical analysis for measuring the displacement of the probe, the probe is installed on the surface of the cured resin layer at the end of the laminate, and the deflection setting value of the probe at the start of measurement is −4 V, the heating rate A method for producing a packaging material for a battery, wherein a material in which the position of the probe does not lower than an initial value when the probe is heated from 40 ° C. to 220 ° C. under a condition of 5 ° C./min is used as the cured resin layer.

According to the battery packaging material of the present invention, a battery packaging material having high insulation and durability can be provided. That is, by sealing the battery element with the battery packaging material of the present invention, the insulation and durability of the battery can be enhanced.

It is a schematic sectional drawing of an example of the packaging material for batteries which concerns on this invention. It is a schematic sectional drawing of an example of the packaging material for batteries which concerns on this invention. It is a schematic sectional drawing of an example of the packaging material for batteries which concerns on this invention. FIG. 5 is an example of a cross-sectional structure of a battery packaging material, and is a diagram for illustrating a position where a probe is installed (an adhesive layer surface of a cross section of the battery packaging material) in a thermomechanical analysis for measuring a displacement amount of the probe. It is a conceptual diagram of the position change of the probe in the thermomechanical analysis which measures the displacement amount of a probe. It is a schematic diagram for demonstrating the method of "durability evaluation" in an Example. It is a schematic diagram for demonstrating the method of "insulation evaluation with respect to foreign material biting" in an Example. The probe is installed on the surface of the cured resin layer in the cross section of the battery packaging material obtained in Example 3, and the relationship between the heating temperature when the probe is heated from 40 ° C. to 250 ° C. and the displacement of the probe position is shown. It is a graph. The probe is installed on the surface of the cured resin layer in the cross section of the battery packaging material obtained in Comparative Example 3, and the relationship between the heating temperature and the displacement of the probe position when the probe is heated from 40 ° C. to 250 ° C. is shown. It is a graph. In the thermomechanical analysis which measures the displacement amount of a probe, it is a schematic perspective view for showing the position (5 places) where a probe is installed.

In the present invention, the battery packaging material is composed of a laminate including at least a base material layer, a barrier layer, a cured resin layer, and a heat-fusible resin layer in this order. In the thermomechanical analysis to be measured, a probe is placed on the surface of the cured resin layer in the cross section of the laminate, and the probe deflection setting value at the start of measurement is -4V and the temperature rise rate is 5 ° C / min. It is characterized in that the position of the probe does not fall below the initial value when the is heated from 40 ° C. to 220 ° C. Hereinafter, the battery packaging material of the present invention, the manufacturing method thereof, and the battery of the present invention in which the battery element is sealed with the battery packaging material of the present invention will be described in detail with reference to FIGS. 1 to 3.

In this specification, the numerical range indicated by “to” means “above” or “below”. For example, the notation of 2 to 15 mm means 2 mm or more and 15 mm or less.

1. As shown in FIG. 1, the battery packaging material of the present invention comprises at least a base material layer 1, a barrier layer 3, a cured resin layer 4, and a heat-fusible resin layer 5 in this order. It consists of a provided laminate. In the battery packaging material of the present invention, the base material layer 1 is the outermost layer side, and the heat-fusible resin layer 5 is the innermost layer. That is, at the time of battery assembly, the heat sealing resin layers 5 positioned at the periphery of the battery element are thermally fused together to seal the battery element, thereby sealing the battery element.

As shown in FIG. 2, the battery packaging material of the present invention includes an adhesive layer 2 between the base material layer 1 and the barrier layer 3 as necessary for the purpose of enhancing the adhesiveness thereof. Also good. As shown in FIG. 3, a surface coating layer 6 may be provided on the surface of the base material layer 1 opposite to the barrier layer 3.

The thickness of the laminate constituting the battery packaging material of the present invention is not particularly limited, but preferably from the viewpoint of exhibiting high insulation and durability while reducing the thickness of the laminate as much as possible. 160 μm or less, more preferably about 35 to 155 μm, still more preferably about 45 to 120 μm. Even when the thickness of the laminate constituting the battery packaging material of the present invention is as thin as 160 μm or less, for example, the present invention can exhibit excellent insulation. For this reason, the packaging material for batteries of this invention can contribute to the improvement of the energy density of a battery.

2. Each layer forming the battery packaging material [base material layer 1]
In the battery packaging material of the present invention, the base material layer 1 is a layer located on the outermost layer side. The material for forming the base material layer 1 is not particularly limited as long as it has insulating properties. Examples of the material for forming the base material layer 1 include resin films such as polyester resin, polyamide resin, epoxy resin, acrylic resin, fluorine resin, polyurethane resin, silicon resin, phenol resin, and mixtures and copolymers thereof. Can be mentioned. Moreover, you may form the base material layer 1 by apply | coating resin. Among these, Preferably a polyester resin and a polyamide resin are mentioned, More preferably, a biaxially stretched polyester resin and a biaxially stretched polyamide resin are mentioned. Specific examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolyester, and polycarbonate. Specific examples of the polyamide resin include nylon 6, nylon 66, a copolymer of nylon 6 and nylon 66,

nylon

6,10, polymetaxylylene adipamide (MXD6), and the like.

The base material layer 1 may be formed of a single resin film, but may be formed of two or more resin films in order to improve pinhole resistance and insulation. Specific examples include a multilayer structure in which a polyester film and a nylon film are laminated, a multilayer structure in which a plurality of nylon films are laminated, and a multilayer structure in which a plurality of polyester films are laminated. When the base material layer 1 has a multilayer structure, a laminate of a biaxially stretched nylon film and a biaxially stretched polyester film, a laminate of a plurality of biaxially stretched nylon films, and a laminate of a plurality of biaxially stretched polyester films The body is preferred. For example, when the base material layer 1 is formed from two resin films, the polyester resin and the polyester resin are laminated, the polyamide resin and the polyamide resin are laminated, or the polyester resin and the polyamide resin are laminated. It is preferable to use a structure in which polyethylene terephthalate and polyethylene terephthalate are laminated, a structure in which nylon and nylon are laminated, or a structure in which polyethylene terephthalate and nylon are laminated. In addition, since the polyester resin is difficult to discolor when, for example, the electrolytic solution adheres to the surface, it is preferable to laminate the base material layer 1 so that the polyester resin is located in the outermost layer in the laminated configuration. When the base material layer 1 has a multilayer structure, the thickness of each layer is preferably about 2 to 25 μm.

When the base material layer 1 is formed of a multilayer resin film, two or more resin films may be laminated via an adhesive component such as an adhesive or an adhesive resin, and the type and amount of the adhesive component used. Is the same as that of the adhesive layer 2 described later. In addition, it does not restrict | limit especially as a method of laminating | stacking two or more resin films, A well-known method can be employ | adopted, for example, a dry lamination method, a sandwich lamination method, etc. are mentioned, Preferably the dry lamination method is mentioned. When laminating by a dry laminating method, it is preferable to use a polyurethane adhesive as the adhesive layer. At this time, the thickness of the adhesive layer is, for example, about 2 to 5 μm.

In the present invention, it is preferable that a lubricant is present on the surface of the base material layer 1 from the viewpoint of improving the moldability of the battery packaging material. Although it does not restrict | limit especially as a lubricant, Preferably an amide type lubricant is mentioned. Specific examples of the amide-based lubricant include saturated fatty acid amide, unsaturated fatty acid amide, substituted amide, methylolamide, saturated fatty acid bisamide, unsaturated fatty acid bisamide, and the like. Specific examples of the saturated fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxy stearic acid amide and the like. Specific examples of the unsaturated fatty acid amide include oleic acid amide and erucic acid amide. Specific examples of the substituted amide include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide and the like. Specific examples of methylolamide include methylol stearamide. Specific examples of saturated fatty acid bisamides include methylene bis stearamide, ethylene biscapric amide, ethylene bis lauric acid amide, ethylene bis stearic acid amide, ethylene bishydroxy stearic acid amide, ethylene bisbehenic acid amide, hexamethylene bis stearic acid amide. And acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N, N′-distearyl adipic acid amide, N, N′-distearyl sebacic acid amide, and the like. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide Etc. Specific examples of the fatty acid ester amide include stearoamidoethyl stearate. Specific examples of the aromatic bisamide include m-xylylene bis stearic acid amide, m-xylylene bishydroxy stearic acid amide, N, N′-distearyl isophthalic acid amide and the like. One type of lubricant may be used alone, or two or more types may be used in combination.

When a lubricant is present on the surface of the base material layer 1, the amount of the lubricant is not particularly limited, but is preferably about 3 mg / m ² or more, more preferably 4 to 15 mg / m in an environment of a temperature of 24 ° C. and a humidity of 60%. ^{About 2} , more preferably about 5 to 14 mg / m ² .

The base material layer 1 may contain a lubricant. Further, the lubricant present on the surface of the base material layer 1 may be obtained by leaching the lubricant contained in the resin constituting the base material layer 1 or by applying a lubricant to the surface of the base material layer 1. It may be.

The thickness of the base material layer 1 is not particularly limited as long as it functions as a base material layer. For example, the thickness is about 3 to 50 μm, preferably about 10 to 35 μm.

[Adhesive layer 2]
In the battery packaging material of the present invention, the adhesive layer 2 is a layer provided between the base material layer 1 and the barrier layer 3 as necessary in order to firmly bond them.

The adhesive layer 2 is formed of an adhesive capable of bonding the base material layer 1 and the barrier layer 3 together. The adhesive used for forming the adhesive layer 2 may be a two-component curable adhesive or a one-component curable adhesive. Further, the adhesive used for forming the adhesive layer 2 is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a heat melting type, a hot pressure type, and the like.

Specific examples of adhesive components that can be used to form the adhesive layer 2 include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolyester; polyethers Polyurethane adhesives; epoxy resins; phenolic resins; polyamide resins such as nylon 6, nylon 66, nylon 12, copolymer polyamides; polyolefins such as polyolefins, carboxylic acid modified polyolefins, metal modified polyolefins Resin, polyvinyl acetate resin; cellulosic adhesive; (meth) acrylic resin; polyimide resin; polycarbonate; amino resin such as urea resin and melamine resin; chloroprene rubber, nitrile rubber, - Len rubbers such as butadiene rubber, silicone-based resins. These adhesive components may be used individually by 1 type, and may be used in combination of 2 or more type. Among these adhesive components, a polyurethane adhesive is preferable.

The polyurethane adhesive is, for example, a polyurethane adhesive containing a main component containing a polyol component (A) and a curing agent containing a polyisocyanate component (B), and the polyol component (A) is a polyester. Polyester polyol containing a polyol (A1), wherein the polyester polyol (A1) is composed of a polybasic acid component and a polyhydric alcohol component and having a number average molecular weight of 5,000 to 50,000, in 100 mol% of the polybasic acid component, The aromatic polybasic acid component is contained in an amount of 45 to 95 mol%, and the tensile stress at 100% elongation of the adhesive layer is 100 kg / cm ² or more and 500 kg / cm ² or less. Also, for example, a polyurethane adhesive for battery packaging materials containing a main agent and a polyisocyanate curing agent, wherein the main agent is a polyester polyol (A1) having a glass transition temperature of 40 ° C. or more and 5 to 50% by weight and glass. Polyester polyol (A2) having a transition temperature of less than 40 ° C. A polyol component (A) containing 95 to 50% by weight and a silane coupling agent (B), and the total of hydroxyl groups and carboxyl groups derived from the polyol component (A) And an equivalent ratio [NCO] / ([OH] + [COOH]) of isocyanate groups contained in the curing agent to 1 to 30 may be mentioned.

Further, the adhesive layer 2 may contain a colorant. When the adhesive layer 2 includes a colorant, the battery packaging material can be colored. As the colorant, known ones such as pigments and dyes can be used. Moreover, only 1 type may be used for a coloring agent, and 2 or more types may be mixed and used for it.

For example, specific examples of inorganic pigments preferably include carbon black and titanium oxide. Specific examples of organic pigments preferably include azo pigments, phthalocyanine pigments, and condensed polycyclic pigments. Examples of azo pigments include soluble pigments such as watching red and force-min 6C; insoluble azo pigments such as monoazo yellow, disazo yellow, pyrazolone orange, pyrazolone red, and permanent red, and phthalocyanine pigments include copper phthalocyanine pigments. And blue pigments and green pigments as metal-free phthalocyanine pigments, and condensed polycyclic pigments include dioxazine violet and quinacridone violet. As the pigment, a pearl pigment, a fluorescent pigment, or the like can be used.

Among the colorants, for example, carbon black is preferable in order to make the appearance of the battery packaging material black.

The average particle diameter of the pigment is not particularly limited, and examples thereof include about 0.05 to 5 μm, preferably about 0.08 to 2 μm. In addition, let the average particle diameter of a pigment be the median diameter measured with the laser diffraction / scattering type particle size distribution measuring apparatus.

The content of the pigment in the adhesive layer 2 is not particularly limited as long as the battery packaging material is colored, and examples thereof include about 5 to 60% by mass.

The thickness of the adhesive layer 2 is not particularly limited as long as it functions as a cured resin layer, and for example, it may be about 1 to 10 μm, preferably about 2 to 5 μm.

[Colored layer]
The colored layer is a layer provided as necessary between the base material layer 1 and the adhesive layer 2 (illustration is omitted). By providing the colored layer, the battery packaging material can be colored.

The colored layer can be formed, for example, by applying an ink containing a colorant to the surface of the base material layer 1 or the surface of the barrier layer 3. As the colorant, known ones such as pigments and dyes can be used. Moreover, only 1 type may be used for a coloring agent, and 2 or more types may be mixed and used for it.

Specific examples of the colorant contained in the colored layer are the same as those exemplified in the column of [Adhesive layer 2].

[Barrier layer 3]
In the battery packaging material, the barrier layer 3 is a layer having a function of preventing water vapor, oxygen, light and the like from entering the battery, in addition to improving the strength of the battery packaging material. The barrier layer 3 can be formed of a metal foil, a metal vapor-deposited film, an inorganic oxide vapor-deposited film, a carbon-containing inorganic oxide vapor-deposited film, a film provided with these vapor-deposited layers, or the like, and is a layer formed of metal. Preferably there is. Specific examples of the metal constituting the barrier layer 3 include aluminum, stainless steel, titanium steel, and preferably aluminum. The barrier layer 3 can be formed by, for example, a metal foil, a metal vapor-deposited film, an inorganic oxide vapor-deposited film, a carbon-containing inorganic oxide vapor-deposited film, a film provided with these vapor-deposited films, etc. It is more preferable to form with aluminum foil or stainless steel foil. From the viewpoint of preventing the generation of wrinkles and pinholes in the barrier layer 3 during the production of the battery packaging material, the barrier layer is made of, for example, annealed aluminum (JIS H4160: 1994 A8021H-O, JIS H4160: 1994 A8079H-O, JIS H4000: 2014 A8021P-O, JIS H4000: 2014 A8079P-O) and the like are more preferable.

Also, examples of the stainless steel foil include austenitic stainless steel foil and ferritic stainless steel foil. The stainless steel foil is preferably made of austenitic stainless steel.

Specific examples of the austenitic stainless steel constituting the stainless steel foil include SUS304, SUS301, SUS316L, and among these, SUS304 is particularly preferable.

The thickness of the barrier layer 3 is not particularly limited as long as it functions as a barrier layer such as water vapor. For example, the upper limit is preferably about 85 μm or less, more preferably about 50 μm or less, and still more preferably 40 μm or less. The lower limit is preferably about 10 μm or more, and the thickness range is about 10 to 80 μm, preferably about 10 to 50 μm. When the barrier layer 3 is made of stainless steel foil, the thickness of the stainless steel foil is preferably about 85 μm or less, more preferably about 50 μm or less, still more preferably about 40 μm or less, and further preferably about 30 μm or less. Particularly preferred is about 25 μm or less, and the lower limit is about 10 μm or more, and the preferred thickness range is about 10 to 85 μm, about 10 to 50 μm, more preferably about 10 to 40 μm, more preferably About 10 to 30 μm, more preferably about 15 to 25 μm.

The barrier layer 3 is preferably subjected to chemical conversion treatment on at least one side, preferably both sides, in order to stabilize adhesion, prevent dissolution and corrosion, and the like. Here, the chemical conversion treatment refers to a treatment for forming an acid-resistant film on the surface of the barrier layer. When an acid resistant film is formed on the surface of the barrier layer 3 of the present invention, the barrier layer 3 includes an acid resistant film. As the chemical conversion treatment, for example, chromate chromate using chromic acid compounds such as chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, chromic acetyl acetate, chromium chloride, potassium sulfate chromium, etc. Treatment: Phosphoric acid chromate treatment using a phosphoric acid compound such as sodium phosphate, potassium phosphate, ammonium phosphate, polyphosphoric acid; aminated phenol having a repeating unit represented by the following general formulas (1) to (4) Examples include chromate treatment using a polymer. In the aminated phenol polymer, the repeating units represented by the following general formulas (1) to (4) may be contained singly or in any combination of two or more. Also good.

In the general formulas (1) to (4), X represents a hydrogen atom, a hydroxyl group, an alkyl group, a hydroxyalkyl group, an allyl group or a benzyl group. R ¹ and R ² are the same or different and each represents a hydroxyl group, an alkyl group, or a hydroxyalkyl group. In the general formulas (1) to (4), examples of the alkyl group represented by X, R ¹ and R ² include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, Examples thereof include a linear or branched alkyl group having 1 to 4 carbon atoms such as a tert-butyl group. Examples of the hydroxyalkyl group represented by X, R ¹ and R ² include a hydroxymethyl group, a 1-hydroxyethyl group, a 2-hydroxyethyl group, a 1-hydroxypropyl group, a 2-hydroxypropyl group, 3- C1-C4 straight or branched chain in which one hydroxyl group such as hydroxypropyl group, 1-hydroxybutyl group, 2-hydroxybutyl group, 3-hydroxybutyl group, 4-hydroxybutyl group is substituted An alkyl group is mentioned. In the general formulas (1) to (4), the alkyl group and hydroxyalkyl group represented by X, R ¹ and R ² may be the same or different. In the general formulas (1) to (4), X is preferably a hydrogen atom, a hydroxyl group or a hydroxyalkyl group. The number average molecular weight of the aminated phenol polymer having a repeating unit represented by the general formulas (1) to (4) is preferably about 500 to 1,000,000, for example, about 1,000 to 20,000. More preferred.

Further, as a chemical conversion treatment method for imparting corrosion resistance to the barrier layer 3, a phosphoric acid is coated with a metal oxide such as aluminum oxide, titanium oxide, cerium oxide, tin oxide, or barium sulfate fine particles dispersed therein. A method of forming an acid-resistant film on the surface of the barrier layer 3 by performing a baking treatment at 150 ° C. or higher can be mentioned. Further, a resin layer obtained by crosslinking a cationic polymer with a crosslinking agent may be further formed on the acid resistant film. Here, examples of the cationic polymer include polyethyleneimine, an ionic polymer complex composed of a polymer having polyethyleneimine and a carboxylic acid, a primary amine graft acrylic resin obtained by graft polymerization of a primary amine on an acrylic main skeleton, and polyallylamine. Or the derivative, aminophenol, etc. are mentioned. As these cationic polymers, only one type may be used, or two or more types may be used in combination. Examples of the crosslinking agent include a compound having at least one functional group selected from the group consisting of an isocyanate group, a glycidyl group, a carboxyl group, and an oxazoline group, and a silane coupling agent. As these crosslinking agents, only one type may be used, or two or more types may be used in combination.

As a specific method of providing an acid-resistant film, for example, as an example, at least the surface on the inner layer side of an aluminum foil (barrier layer) is first subjected to an alkali dipping method, electrolytic cleaning method, acid cleaning method, electrolytic A degreasing treatment is performed by a known treatment method such as an acid cleaning method or an acid activation method, and then a phosphoric acid Cr (chromium) salt, phosphoric acid Ti (titanium) salt, phosphoric acid Zr (zirconium) salt, phosphorus Treatment liquid (aqueous solution) mainly composed of a metal phosphate such as Zn (zinc) salt and a mixture of these metals, or a mixture of a non-metal phosphate and a mixture of these non-metals A treatment liquid (aqueous solution) or a mixture of these with a water-based synthetic resin such as an acrylic resin, a phenol resin, or a polyurethane resin. By coating in a known coating method of the immersion method, it is possible to form the acid-resistant coating. For example, when treated with a Cr (chromium) phosphate-based treatment solution, CrPO ₄ (chromium phosphate), AlPO ₄ (aluminum phosphate), Al ₂ O ₃ (aluminum oxide), Al (OH) _x (water Zn ₂ PO ₄ · 4H ₂ O (zinc phosphate hydrate) when treated with an acid-resistant film made of aluminum oxide), AlF _x (aluminum fluoride), etc. ), AlPO ₄ (aluminum phosphate), Al ₂ O ₃ (aluminum oxide), Al (OH) _x (aluminum hydroxide), AlF _x (aluminum fluoride), and the like.

In addition, as another example of a specific method for providing an acid-resistant film, for example, at least the surface on the inner layer side of the aluminum foil, first, an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, an acid activity An acid-resistant film can be formed by performing a degreasing process by a known processing method such as a chemical conversion method and then performing a known anodizing process on the degreasing surface.

As another example of the acid-resistant film, a film of a phosphorus compound (for example, phosphate-based) or a chromium compound (for example, chromic acid-based) can be given. Examples of the phosphate system include zinc phosphate, iron phosphate, manganese phosphate, calcium phosphate, and chromium phosphate. Examples of the chromic acid system include chromium chromate.

In addition, as another example of an acid-resistant film, by forming an acid-resistant film such as a phosphorus compound (phosphate, etc.), a chromium compound (chromate, etc.), a fluoride, a triazine thiol compound, etc., during emboss molding Prevention of delamination between aluminum and base material layer, and dissolution and corrosion of aluminum surface, especially aluminum oxide existing on the surface of aluminum, due to hydrogen fluoride generated by reaction between electrolyte and moisture In addition, the adhesion (wetting) of the aluminum surface is improved, the delamination between the base material layer and aluminum during heat sealing is prevented, and in the embossed type, the delamination between the base material layer and aluminum during press molding is performed. Shows the effect of preventing lamination. Among substances that form an acid-resistant film, an aqueous solution composed of three components of a phenolic resin, a chromium fluoride (3) compound, and phosphoric acid is applied to the aluminum surface, and the dry baking treatment is good.

The acid-resistant film includes a layer having cerium oxide, phosphoric acid or phosphate, an anionic polymer, and a crosslinking agent that crosslinks the anionic polymer, and the phosphoric acid or phosphate is 1 to 100 parts by mass may be blended with 100 parts by mass of cerium oxide. It is preferable that the acid-resistant film has a multilayer structure further including a layer having a cationic polymer and a crosslinking agent for crosslinking the cationic polymer.

Furthermore, it is preferable that the anionic polymer is poly (meth) acrylic acid or a salt thereof, or a copolymer containing (meth) acrylic acid or a salt thereof as a main component. Moreover, it is preferable that the said crosslinking agent is at least 1 sort (s) chosen from the group which has a functional group in any one of an isocyanate group, a glycidyl group, a carboxyl group, and an oxazoline group, and a silane coupling agent.

The phosphoric acid or phosphate is preferably condensed phosphoric acid or condensed phosphate.

As the chemical conversion treatment, only one type of chemical conversion treatment may be performed, or two or more types of chemical conversion processing may be performed in combination. Furthermore, these chemical conversion treatments may be carried out using one kind of compound alone, or may be carried out using a combination of two or more kinds of compounds. Among the chemical conversion treatments, chromic acid chromate treatment, chromate treatment combining a chromic acid compound, a phosphoric acid compound, and an aminated phenol polymer are preferable.

Specific examples of the acid-resistant film include those containing at least one of phosphates, chromates, fluorides, and triazine thiol compounds. An acid resistant film containing a cerium compound is also preferable. As the cerium compound, cerium oxide is preferable.

Specific examples of the acid resistant film include a phosphate film, a chromate film, a fluoride film, and a triazine thiol compound film. As an acid-resistant film, one of these may be used, or a plurality of combinations may be used. Furthermore, as an acid-resistant film, after degreasing the chemical conversion treatment surface of the barrier layer, from a treatment liquid composed of a mixture of a metal phosphate and an aqueous synthetic resin, or a mixture of a non-metal phosphate and an aqueous synthetic resin It may be formed with a treatment liquid.

The composition of the acid resistant film can be analyzed using, for example, time-of-flight secondary ion mass spectrometry.

The amount of the acid-resistant film formed on the surface of the barrier layer 3 in the chemical conversion treatment is not particularly limited. For example, if the above chromate treatment is performed, the chromic acid compound is present per 1 m ² of the surface of the barrier layer 3. About 0.5 to 50 mg, preferably about 1.0 to 40 mg in terms of chromium, about 0.5 to 50 mg, preferably about 1.0 to 40 mg in terms of phosphorus, and 1. It is desirable that it is contained in a proportion of about 0 to 200 mg, preferably about 5.0 to 150 mg.

The thickness of the acid-resistant film is not particularly limited, but is preferably about 1 nm to 20 μm, more preferably about 1 nm to 100 nm, from the viewpoint of the cohesive strength of the film and the adhesive strength with the barrier layer and the heat-fusible resin layer. More preferably, about 1 nm to 50 nm is mentioned. The thickness of the acid-resistant film can be measured by observation with a transmission electron microscope, or a combination of observation with a transmission electron microscope and energy dispersive X-ray spectroscopy or electron energy loss spectroscopy. By analyzing the composition of the acid-resistant film using time-of-flight secondary ion mass spectrometry, for example, at least one secondary ion composed of Ce, P and O (for example, Ce ₂ PO ₄ ⁺ , CePO ₄ ^−, etc.) ) Or a peak derived from a secondary ion composed of Cr, P, and O (for example, at least one kind of CrPO ₂ ⁺ , CrPO ₄ ^−, etc.) is detected.

In the chemical conversion treatment, a solution containing a compound used for forming an acid-resistant film is applied to the surface of the barrier layer by a bar coating method, a roll coating method, a gravure coating method, a dipping method, etc., and then the temperature of the barrier layer is 70. It is performed by heating to about 200 ° C. In addition, before the chemical conversion treatment is performed on the barrier layer, the barrier layer may be previously subjected to a degreasing treatment by an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, or the like. By performing the degreasing process in this manner, it is possible to more efficiently perform the chemical conversion process on the surface of the barrier layer.

[Curing resin layer 4]
In the present invention, the cured resin layer 4 is a layer provided between the barrier layer 3 and the heat-fusible resin layer 5 in order to enhance the insulation and durability of the battery packaging material.

In the present invention, in the thermomechanical analysis for measuring the displacement of the probe, the cured resin layer 4 is provided with a probe on the surface of the cured resin layer in the cross section of the battery packaging material (laminate), When the probe is heated from 40 ° C. to 220 ° C. under the conditions of the deflection set value of −4 V and the heating rate of 5 ° C./min, the probe position is not lowered from the initial value.

In the thermomechanical analysis for measuring the displacement of the probe, for example, as shown in the conceptual diagram of FIG. 5, first, the thermomechanical analysis apparatus is applied to the surface of the cured resin layer 4 in the cross section of the battery packaging material (laminate). The probe 10 is installed (measurement start A in FIG. 5). The cross section at this time is a portion where the cross section of the cured resin layer 4 obtained by cutting in the thickness direction so as to pass through the center of the battery packaging material is exposed. Cutting can be performed using a commercially available rotary microtome or the like. When the amount of displacement is measured for battery packaging materials used in batteries encapsulating electrolytes, etc., the portions where the heat-fusible resin layers of the battery packaging materials are heat-sealed together. , Measure. As a thermomechanical analysis device, an atomic force microscope to which a cantilever with a heating mechanism can be attached can be used. For example, an afm plus system manufactured by ANASIS INSTRUMENTS is used, and a cantilever ThermoLever AN2-200 (spring) A constant of 0.5-3 N / m) can be used. The tip radius of the probe 10 is 30 nm or less, the set value of the deflection of the probe 10 is −4 V, and the temperature rising rate is 5 ° C./min. Next, when the probe is heated in this state, the surface of the cured resin layer 4 expands by the heat from the probe as shown in FIG. 5B, the probe 10 is pushed up, and the position of the probe 10 is set to the initial value (probe of the probe). The temperature rises more than the position when the temperature is 40 ° C. When the temperature further increases, the cured resin layer 4 softens, and the probe 10 pierces the cured resin layer 4 as shown in FIG. 5C, and the position of the probe 10 decreases. In thermomechanical analysis for measuring the displacement of the probe, the battery packaging material to be measured is in a room temperature (25 ° C.) environment, and a probe heated to 40 ° C. is placed on the surface of the cured resin layer 4. Start the measurement. The displacement of the probe is measured by preparing a cross section along the thickness direction of the battery packaging material, measuring five sections of the cross section (see FIG. 10), and adopting the average value as the measurement value. Note that the thickness direction and the vertical direction of the cross section may be any direction (for example, TD), and the temperature at which the position of the probe is lower than the initial value in any direction may be 130 ° C. or lower. . Also, calibration is performed five times and an average value is adopted.

In the present invention, since the displacement of the probe is measured from the cross section of the laminate of the battery packaging material, when measuring from the surface of the material forming the adhesive layer (before becoming the battery packaging material) In comparison, the thermal behavior of only the adhesive layer can be measured in a state close to the state of use in a battery. That is, when the material for the adhesive layer is applied to a film substrate or the like, and the softening temperature or the like is measured from the surface by TMA or the like, the thickness required for the measurement is 10 times or more thicker than the actual thickness of the adhesive layer. The thermal behavior differs because the degree of curing and the bonding state when actually used as a battery packaging material are different. In this case, the influence of the thermal behavior of the film substrate or the like may overlap, and it cannot be said that the thermomechanical properties of only the adhesive layer are measured.

In the battery packaging material of the present invention, from the viewpoint of further improving the insulation and durability, the probe deflection setting value at the start of measurement is −4 V, and the temperature rising rate is 5 ° C./min. Is heated from 40 ° C. to 220 ° C., the position of the probe 10 installed on the surface of the cured resin layer 4 is not lowered from the initial value (position when the probe temperature is 40 ° C.), and further 160 ° C. It is more preferable that the position of the probe 10 installed on the surface of the cured resin layer 4 is not lowered when heated to 200 ° C. The step of heat-sealing the heat-fusible resin layers of the battery packaging material to seal the battery element is usually performed by heating at about 160 ° C. to 200 ° C. For this reason, when the probe is heated from 160 ° C. to 200 ° C., the battery packaging material in which the position of the probe 10 placed on the surface of the cured resin layer 4 does not decrease can exhibit particularly high insulation and durability. . From the viewpoint of further increasing the insulation and durability, when the probe is heated from 40 ° C. to 250 ° C., the position of the probe 10 installed on the surface of the cured resin layer 4 does not decrease from the initial value, and further, 160 ° C. It is more preferable that the position of the probe 10 installed on the surface of the cured resin layer 4 is not lowered when heated to 200 ° C.

From the same viewpoint, in thermomechanical analysis for measuring the displacement of the probe 10, the probe 10 is placed on the surface of the cured resin layer 4 in the cross section of the battery packaging material (laminate), and the probe is moved from 40 ° C. to 220 ° C. It is preferable that the amount of increase in the position of the probe 10 when heated from 140 ° C. to 220 ° C. is larger than the amount of increase in the position of the probe 10 when heated from 80 ° C. to 120 ° C. When the probe is heated from 40 ° C. to 250 ° C., the amount of increase in the position of the probe 10 when heated from 140 ° C. to 250 ° C. is greater than the amount of increase in the position of the probe 10 when heated from 80 ° C. to 120 ° C. Is preferably larger. Further, the difference between the amount of increase in the position of the probe 10 when heated from 80 ° C. to 120 ° C. and the amount of increase in the position of the probe 10 when heated from 140 ° C. to 220 ° C. is preferably 0 V or more, 0 .05V or more, 0.1V or more.

As described above, in the battery manufacturing process, minute foreign matters such as electrode active material and electrode tab fragments may adhere to the surface of the heat-fusible resin layer. A thin part and a through-hole are produced, and there exists a possibility that insulation may fall. On the other hand, the battery packaging material of the present invention has the above-mentioned characteristics in the thermomechanical analysis for measuring the displacement amount of the probe 10. Insulation and durability of battery packaging materials even when minute foreign matter is present at the heat-sealed parts such as the interface between heat-sealable resin layers or between electrode tabs and heat-sealable resin layers Sexuality is enhanced.

In the present invention, the cured resin layer 4 only needs to be composed of a cured resin that exhibits the above characteristics. From the viewpoint of firmly bonding the barrier layer 3 and the heat-fusible resin layer 5 to exhibit high insulation and durability in the battery packaging material, the cured resin layer 4 is a resin composition containing an acid-modified polyolefin. The cured product is preferably.

In the present invention, 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 invention, “(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 the propylene unit contained in the polypropylene is preferably about 50 to 100 mol%, more preferably about 80 to 100 mol%, from the viewpoint of further improving the insulation and durability of the battery packaging material. . Further, the proportion of the ethylene unit contained in the polyethylene is preferably about 50 to 100 mol%, more preferably about 80 to 100 mol%, from the viewpoint of further improving the insulation and durability of the battery packaging material. More preferred. 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.

In the cured resin layer 4, among the acid-modified polyolefins, maleic anhydride-modified polyolefin, and further maleic anhydride-modified polypropylene are particularly preferable.

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 (meth) acrylic acid esters include esterification products of (meth) acrylic acid and alcohols having 1 to 30 carbon atoms, preferably esterification products of (meth) acrylic acid and alcohols having 1 to 20 carbon atoms. Is mentioned. 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 the acid anhydride thereof in the acid-modified polyolefin is preferably about 0.1 to 30% by mass, more preferably about 0.1 to 20% by mass. By setting it as such a range, the insulation and durability of the packaging material for batteries can be improved more.

Further, the ratio of (meth) acrylic acid ester in the acid-modified polyolefin is preferably about 0.1 to 40% by mass, and more preferably about 0.1 to 30% by mass. By setting it as such a range, the insulation and durability of the packaging material for batteries can be improved more.

The weight average molecular weight of the acid-modified polyolefin is preferably about 6000 to 200000, and more preferably about 8000 to 150,000, respectively. In the present invention, 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. The melting peak temperature of the acid-modified polyolefin is preferably about 50 to 120 ° C., more preferably about 50 to 100 ° C. In the present invention, the melting peak temperature of the acid-modified polyolefin refers to an endothermic peak temperature in differential scanning calorimetry.

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.

Further, from the viewpoint of firmly bonding the barrier layer 3 and the heat-fusible resin layer 5 and exhibiting high insulation and durability in the battery packaging material, the cured resin layer 4 is a compound having an isocyanate group, It is preferably a cured product of a resin composition containing at least one selected from the group consisting of a compound having an oxazoline group, an epoxy resin, and a urethane resin, and a resin containing at least one of these and the acid-modified polyolefin More preferably, it is a cured product of the composition. That is, the resin constituting the cured resin layer 4 may or may not include a polyolefin skeleton, and preferably includes a polyolefin skeleton. The fact that the resin constituting the cured resin layer 4 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography mass spectrometry, etc., and the analysis method is not particularly limited. For example, when measuring the infrared spectroscopy at a maleic anhydride-modified polyolefin, a peak derived from maleic acid is detected in the vicinity of the wave number of 1760 cm ^-1 and near the wave number 1780 cm ^-1. However, if the acid modification degree is low, the peak may be small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy. The cured resin layer 4 preferably includes at least one selected from the group consisting of urethane resins, ester resins, and epoxy resins, and more preferably includes urethane resins and epoxy resins. As the ester resin, for example, an amide ester resin is preferable. Amide ester resins are generally formed by the reaction of carboxyl groups and oxazoline groups. The cured resin layer 4 is more preferably a cured product of a resin composition containing at least one of these resins and the acid-modified polyolefin. In the case where an unreacted product of a curing agent such as a compound having an isocyanate group, a compound having an oxazoline group, or an epoxy resin remains in the cured resin layer 4, the presence of the unreacted material is, for example, infrared spectroscopy. It can be confirmed by a method selected from Raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and the like.

The compound having an isocyanate group is not particularly limited, but a polyfunctional isocyanate compound is preferably used from the viewpoint of exhibiting high insulation and durability in the battery packaging material. The polyfunctional isocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of the polyfunctional isocyanate-based curing agent include isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), those obtained by polymerizing or nurating these, Examples thereof include mixtures and copolymers with other polymers.

The content of the compound having an isocyanate group in the cured resin layer 4 is preferably in the range of 0.5 to 15% by mass in the resin composition constituting the cured resin layer 4, and is preferably 1 to 12% by mass. More preferably, it is in the range. Thereby, the insulation and durability of the battery packaging material can be further improved.

The compound having an oxazoline group is not particularly limited as long as it is a compound having an oxazoline skeleton. Specific examples of the compound having an oxazoline group include those having a polystyrene main chain and those having an acrylic main chain. Moreover, as a commercial item, the Epocross series by Nippon Shokubai Co., Ltd. etc. are mentioned, for example.

The ratio of the compound having an oxazoline group in the cured resin layer 4 is preferably in the range of 0.5 to 15% by mass in the resin composition constituting the cured resin layer 4, and in the range of 1 to 12% by mass. More preferably. Thereby, the insulation and durability of the battery packaging material can be further improved.

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. The weight average molecular weight of the epoxy resin is preferably about 50 to 2000, more preferably about 100 to 1000, and still more preferably about 200 to 800. In the present invention, 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.

Specific examples of the epoxy resin include bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolac glycidyl ether, glycerin polyglycidyl ether, and polyglycerin polyglycidyl ether. An epoxy resin may be used individually by 1 type, and may be used in combination of 2 or more types.

The ratio of the epoxy resin in the cured resin layer 4 is preferably in the range of 0.5 to 15% by mass, preferably in the range of 1 to 12% by mass in the resin composition constituting the cured resin layer 4. Is more preferable. Thereby, the insulation and durability of the battery packaging material can be further improved.

The urethane resin is not particularly limited, and a known urethane resin can be used. The cured resin layer 4 may be, for example, a cured product of a two-component curable urethane resin.

The ratio of the urethane resin in the cured resin layer 4 is preferably in the range of 0.5 to 20% by mass, preferably in the range of 1 to 15% by mass in the resin composition constituting the cured resin layer 4. Is more preferable. Thereby, the insulation and durability of the battery packaging material can be further improved. The cured resin layer 4 may be made of a urethane resin.

In the present invention, the cured resin layer 4 is a resin composition comprising at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and an epoxy resin, and the acid-modified polyolefin. In the case of a cured product, the acid-modified polyolefin functions as a main agent, and the compound having an isocyanate group, the compound having an oxazoline group, and the epoxy resin each function as a curing agent.

Further, from the viewpoint of further improving the adhesion between the barrier layer 3 (or acid-resistant film), the heat-fusible resin layer 5 and the cured resin layer 4, the cured resin layer 4 has an oxygen atom, a heterocyclic ring, and a C = N bond. And a cured product of a resin composition containing a curing agent having at least one selected from the group consisting of C—O—C bonds. Examples of the curing agent having a heterocyclic ring include a curing agent having an oxazoline group and a curing agent having an epoxy group. Examples of the curing agent having a C═N bond include a curing agent having an oxazoline group and a curing agent having an isocyanate group. Examples of the curing agent having a C—O—C bond include a curing agent having an oxazoline group, a curing agent having an epoxy group, and a urethane resin. The cured resin layer 4 is a cured product of a resin composition containing these curing agents, for example, gas chromatography mass spectrometry (GCMS), infrared spectroscopy (IR), time-of-flight secondary ion mass spectrometry ( It can be confirmed by a method such as TOF-SIMS) or X-ray photoelectron spectroscopy (XPS).

The cured resin layer 4 may contain an additive such as an anti-blocking agent (such as silica), and the additive may be contained in the resin composition.

The softening temperature of the cured resin layer 4 is preferably about 180 ° C. to 260 ° C., more preferably about 200 to 240 ° C. The softening temperature of the cured resin layer 4 is a value measured by a method in accordance with the provisions of JIS K7196: 2012 “Softening temperature test method by thermomechanical analysis of thermoplastic film and sheet”. These are values measured by the method described in the examples.

The solid content of the cured resin layer 4 is not particularly limited, but is preferably about 0.5 to 10 g / m ² , more preferably 0.8 to 5.2 g from the viewpoint of further improving the insulation and durability. / M ² or so. From the same viewpoint, the thickness of the cured resin layer 4 is preferably about 0.6 to 11 μm, more preferably about 0.9 to 5.8 μm. In addition, the thickness of the cured resin layer 4 may be measured with respect to a cross section obtained by cutting the laminate constituting the battery packaging material, or may be applied to the resin composition constituting the cured resin layer. It may be calculated from the amount and the density, and any one may be within these ranges.

[Heat-fusion resin layer 5]
In the battery packaging material of the present invention, the heat-fusible resin layer 5 corresponds to the innermost layer, and is a layer that heat-fuses the heat-fusible resin layers together to seal the battery element when the battery is assembled.

The resin component used in the heat-fusible resin layer 5 of the present invention is not particularly limited as long as it can be heat-sealed, and examples thereof include polyolefins and acid-modified polyolefins. That is, the resin constituting the heat-fusible resin layer 5 may or may not contain a polyolefin skeleton, and preferably contains a polyolefin skeleton. The fact that the resin constituting the heat-fusible resin layer 5 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography mass spectrometry, etc., and the analysis method is not particularly limited. For example, when measuring the infrared spectroscopy at a maleic anhydride-modified polyolefin, a peak derived from maleic acid is detected in the vicinity of the wave number of 1760 cm ^-1 and near the wave number 1780 cm ^-1. However, if the acid modification degree is low, the peak may be small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

Specific examples of polyolefins include polyethylenes such as low density polyethylene, medium density polyethylene, high density polyethylene, and linear low density polyethylene; homopolypropylene, polypropylene block copolymers (for example, block copolymers of propylene and ethylene), polypropylene Polypropylenes such as random copolymers (for example, random copolymers of propylene and ethylene); ethylene-butene-propylene terpolymers; and the like. Among these polyolefins, polyethylene and polypropylene are preferable, and polypropylene is more preferable.

The polyolefin may be a cyclic polyolefin. The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefin that is a constituent monomer of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. It is done. In addition, examples of the cyclic monomer that is a constituent monomer of the cyclic polyolefin include cyclic alkenes such as norbornene; specifically, cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, norbornadiene, and the like. Among these polyolefins, cyclic alkene is preferable, and norbornene is more preferable.

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 acid-modified polyolefin may be an acid-modified cyclic polyolefin. The acid-modified cyclic polyolefin is a copolymer obtained by copolymerizing a part of the monomer constituting the cyclic polyolefin in place of the α, β-unsaturated carboxylic acid or its anhydride, or α, β-unsaturated with respect to the cyclic polyolefin. It is a polymer obtained by block polymerization or graft polymerization of a saturated carboxylic acid or its anhydride. The cyclic polyolefin to be acid-modified is the same as described above. The carboxylic acid used for modification is the same as that used for modification of the acid-modified cycloolefin copolymer.

Among these resin components, preferred are polyolefins, and more preferred are propylene copolymers. 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 the propylene unit contained in the polypropylene is preferably about 50 to 100 mol%, more preferably about 80 to 100 mol%, from the viewpoint of further improving the insulation and durability of the battery packaging material. . Further, the proportion of the ethylene unit contained in the polyethylene is preferably about 50 to 100 mol%, more preferably about 80 to 100 mol%, from the viewpoint of further improving the insulation and durability of the battery packaging material. More preferred. Each of the ethylene copolymer and the propylene copolymer may be a random copolymer or a block copolymer, and a random propylene copolymer is preferred.

The heat-fusible resin layer 5 of the present invention preferably has polypropylene, and preferably has a layer formed of polypropylene. The heat-fusible resin layer 5 may be formed of one kind of resin component alone or may be formed of a blend polymer in which two or more kinds of resin components are combined. Furthermore, the heat-fusible resin layer 5 may be formed of only one layer, but may be formed of two or more layers using the same or different resin components.

When the heat-fusible resin layer 5 of the present invention is formed of a plurality of layers, the innermost layer (the side opposite to the barrier layer 3) of the heat-fusible resin layer 5 is formed by a dry laminating method or extrusion molding. It is preferable that it is a layer. Thereby, insulation and a moldability can be improved further.

The heat-fusible resin layer 5 of the present invention preferably has fine irregularities on the surface (the innermost layer side surface). Thereby, a moldability can be improved further. In addition, as a method of forming fine irregularities on the surface of the heat-fusible resin layer 5, a method of adding additives exemplified in the surface coating layer 6 described later to the heat-fusible resin layer 5, and irregularities on the surface. For example, a method may be used in which the cooling roll is brought into contact with the mold. As the fine irregularities, the ten-point average roughness of the surface of the heat-fusible resin layer 5 is preferably about 0.3 to 35 μm, more preferably about 0.3 to 10 μm, and still more preferably 0.5 to About 2 μm may be mentioned. The ten-point average roughness is a value measured using a Keyence laser microscope VK-9710 under the measurement conditions of 50 times objective lens and no cutoff in a method in accordance with JIS B0601: 1994.

In the present invention, a lubricant is preferably present on the surface of the heat-fusible resin layer 5 from the viewpoint of improving the moldability of the battery packaging material. The lubricant is not particularly limited, and a known lubricant can be used, and examples thereof include those exemplified in the base material layer 1 described above. One type of lubricant may be used alone, or two or more types may be used in combination. The amount of lubricant present on the surface of the heat-fusible resin layer 5 is not particularly limited. From the viewpoint of improving the moldability of the electronic packaging material, it is preferably 10 to 50 mg at a temperature of 24 ° C. and a humidity of 60%. / M ² , more preferably about 15 to 40 mg / m ² .

The heat-fusible resin layer 5 may contain a lubricant. Further, the lubricant present on the surface of the heat-fusible resin layer 5 may be one obtained by leaching the lubricant contained in the resin constituting the heat-fusible resin layer 5, or the heat-fusible resin layer. 5 may be obtained by applying a lubricant to the surface.

In addition, the thickness of the heat-fusible resin layer 5 of the present invention is not particularly limited as long as it exhibits the function as the heat-fusible resin layer. From the viewpoint of further improving the insulation and durability, for example, The thickness is about 10 to 40 μm, preferably about 15 to 40 μm.

[Surface coating layer 6]
In the battery packaging material of the present invention, for the purpose of improving design properties, electrolytic solution resistance, scratch resistance, moldability, etc., the base material layer 1 (barrier layer of the base material layer 1) is optionally formed. If necessary, a surface coating layer 6 may be provided on the side opposite to (3). The surface coating layer 6 is a layer located in the outermost layer when the battery is assembled.

The surface coating layer 6 can be formed of, for example, polyvinylidene chloride, a polyester resin, a urethane resin, an acrylic resin, an epoxy resin, or the like. Of these, the surface coating layer 6 is preferably formed of a two-component curable resin. Examples of the two-component curable resin for forming the surface coating layer 6 include a two-component curable urethane resin, a two-component curable polyester resin, and a two-component curable epoxy resin. Moreover, you may mix | blend an additive with the surface coating layer 6. FIG. The additive to be added may function as, for example, a matting agent, and the surface coating layer may function as a mat layer.

Examples of the additive include fine particles having a particle size of about 0.5 nm to 5 μm. The material of the additive is not particularly limited, and examples thereof include metals, metal oxides, inorganic substances, and organic substances. Further, the shape of the additive is not particularly limited, and examples thereof include a spherical shape, a fibrous shape, a plate shape, an indeterminate shape, and a balloon shape. Specific additives include talc, silica, graphite, kaolin, montmorilloid, montmorillonite, synthetic mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, Neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotubes, high Melting | fusing point nylon, crosslinked acrylic, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold | metal | money, aluminum, copper, nickel etc. are mentioned. These additives may be used individually by 1 type, and may be used in combination of 2 or more type. Among these additives, silica, barium sulfate, and titanium oxide are preferable from the viewpoint of dispersion stability and cost. In addition, the surface of the additive may be subjected to various surface treatments such as insulation treatment and high dispersibility treatment.

The method for forming the surface coating layer 6 is not particularly limited, and examples thereof include a method in which a two-component curable resin for forming the surface coating layer 6 is applied to one surface of the base material layer 1. When blending the additive, the additive may be added to the two-component curable resin, mixed, and then applied.

The thickness of the surface coating layer 6 is not particularly limited as long as it exhibits the above function as the surface coating layer, and may be about 0.5 to 10 μm, preferably about 1 to 5 μm.

3. Production method of battery packaging material The production method of the battery packaging material of the present invention is not particularly limited as long as a laminate in which layers of a predetermined composition are laminated is obtained, and at least a base material layer and a barrier layer In the thermomechanical analysis for measuring the amount of displacement of the probe, the curing of the cross section of the laminate is provided. When the probe is installed on the surface of the resin layer and the probe is heated from 40 ° C. to 220 ° C. under the conditions that the deflection setting of the probe at the start of measurement is −4 V and the temperature rising rate is 5 ° C./min. A method in which a probe whose position of the probe does not fall below an initial value is used as the cured resin layer can be employed. That is, as the cured resin layer 4, the battery packaging material of the present invention can be manufactured by laminating each layer using the layer described in the section “2. Each layer forming the battery packaging material”. .

An example of the method for producing the battery packaging material of the present invention is as follows. First, a laminate including the base material layer 1, the adhesive layer 2, and the barrier layer 3 in this order (hereinafter also referred to as “laminate A”) is formed. Specifically, the laminate A is formed by extruding an adhesive used for forming the adhesive layer 2 on the base material layer 1 or the barrier layer 3 whose surface is subjected to chemical conversion treatment, if necessary, by extrusion, gravure coating After applying and drying by a coating method such as a method or a roll coating method, the barrier layer 3 or the base material layer 1 can be laminated and the adhesive layer 2 can be cured by a dry laminating method.

Next, the cured resin layer 4 and the heat-fusible resin layer 5 are laminated on the barrier layer 3 of the laminate A. When the cured resin layer 4 and the heat-fusible resin layer 5 are laminated on the barrier layer 3, for example, (1) the cured resin layer 4 and the heat-fusible resin layer on the barrier layer 3 of the laminate A (2) Separately, a laminate in which the cured resin layer 4 and the heat-fusible resin layer 5 are laminated is formed, and this is used as a barrier for the laminate A. A method of laminating on the layer 3 by a thermal laminating method; (3) applying the above resin composition for forming the cured resin layer 4 on the barrier layer 3 of the laminate A by a gravure coating method, a roll coating method or the like. After the coating and drying by the method, the heat-fusible resin layer is laminated and the cured resin layer 4 is cured, and (4) the barrier layer 3 of the laminate A and the heat previously formed into a sheet shape Pour the molten cured resin layer 4 between the fusible resin layer 5 While, and a method of bonding a laminate A and the heat-welding resin layer 5 via the cured resin layer 4 (sandwich lamination method). Among these methods, the method (3) is preferable. When the method (3) is employed, it is preferable that the above resin composition for forming the cured resin layer 4 is laminated on the barrier layer 3 and then dried at a temperature of about 60 to 120 ° C. When the heat-fusible resin layer 5 is a plurality of layers, the innermost layer of the heat-fusible resin layer 5 is preferably a layer formed by a dry lamination method or extrusion molding.

When the surface coating layer 6 is provided, the surface coating layer 6 is laminated on the surface of the base material layer 1 opposite to the barrier layer 3. The surface coating layer 6 can be formed, for example, by applying the above-described resin for forming the surface coating layer 6 to the surface of the base material layer 1. The order of the step of laminating the barrier layer 3 on the surface of the base material layer 1 and the step of laminating the surface coating layer 6 on the surface of the base material layer 1 are not particularly limited. For example, after forming the surface coating layer 6 on the surface of the base material layer 1, the barrier layer 3 may be formed on the surface of the base material layer 1 opposite to the surface coating layer 6.

The method of causing the lubricant to be present on the surface of the base material layer 1 or the heat-fusible resin layer 5 is not particularly limited. For example, a lubricant is blended with the resin constituting the base material layer 1 or the heat-fusible resin layer 5. In addition, a method of leaching the lubricant to the surface as necessary, a method of applying the lubricant to the surface of the base material layer 1 or the heat-fusible resin layer 5, and the like can be mentioned.

As described above, the surface coating layer 6, the base material layer 1, the adhesive layer 2 provided if necessary, the barrier layer 3 whose surface is subjected to chemical conversion treatment if necessary, the cured resin layer 4. A laminate comprising the heat-fusible resin layer 5 is formed in this order, but in order to strengthen the adhesiveness of the adhesive layer 2 and the cured resin layer 4 provided as necessary, further heat You may use for heat processing, such as a roll contact type, a hot air type, a near-infrared type, or a far-infrared type. Examples of such heat treatment conditions include a temperature of about 150 to 250 ° C. and a time of about 1 to 5 minutes.

In the battery packaging material of the present invention, each layer constituting the laminate improves or stabilizes film forming properties, lamination processing, suitability for final processing (pouching, embossing), etc., as necessary. Therefore, surface activation treatment such as corona treatment, blast treatment, oxidation treatment, ozone treatment may be performed.

4). Application of Battery Packaging Material The battery packaging material of the present invention is used as a packaging material for sealing and housing battery elements such as a positive electrode, a negative electrode, and an electrolyte.

Specifically, a battery element including at least a positive electrode, a negative electrode, and an electrolyte is formed using the battery packaging material of the present invention, with the metal terminals connected to each of the positive electrode and the negative electrode protruding outward. By covering the periphery of the element so that a flange portion (region where the heat-fusible resin layers are in contact with each other) can be formed, and heat-sealing the heat-fusible resin layers of the flange portion to seal the battery A battery using the packaging material is provided. In addition, when accommodating a battery element using the battery packaging material of the present invention, the battery packaging material of the present invention is used so that the heat-fusible resin portion is on the inner side (surface in contact with the battery element).

The battery packaging material of the present invention may be used for either a primary battery or a secondary battery, but is preferably a secondary battery. The type of secondary battery to which the battery packaging material of the present invention is applied is not particularly limited. For example, a lithium ion battery, a lithium ion polymer battery, a lead battery, a nickel / hydrogen battery, a nickel / cadmium battery , Nickel / iron livestock batteries, nickel / zinc livestock batteries, silver oxide / zinc livestock batteries, metal-air batteries, polyvalent cation batteries, capacitors, capacitors and the like. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries are suitable applications for the battery packaging material of the present invention.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.

The weight average molecular weight of the resin is a value measured by gel permeation chromatography (GPC) measured under conditions using polystyrene as a standard sample. Moreover, the melting peak temperature of the main component of the cured resin layer was measured using a differential scanning calorimeter in accordance with the provisions of JIS K7121: 2012. The softening temperature of the cured film of the cured resin layer was calculated from the penetration temperature in the TMA penetration mode in accordance with the provisions of JIS K7196: 2012. As an apparatus, EXSTAR6000 manufactured by Seiko Instruments Inc. was used.

<Examples 1 to 5 and Comparative Examples 1 to 3>
On a nylon film (thickness 25 μm) as a base material layer, a barrier layer made of an aluminum foil (thickness 35 μm) subjected to chemical conversion treatment on both surfaces was laminated by a dry laminating method. Specifically, a two-component urethane adhesive (a polyol compound and an aromatic isocyanate compound) was applied to one surface of the aluminum foil, and an adhesive layer (thickness 3 μm) was formed on the barrier layer. Subsequently, after laminating the adhesive layer and the base material layer on the barrier layer, an aging treatment was carried out at 40 ° C. for 24 hours to prepare a laminate of the base material layer, the adhesive layer, and the barrier layer. In addition, the chemical conversion treatment of the aluminum foil used as the barrier layer is performed by roll coating a treatment liquid composed of a phenol resin, a chromium fluoride compound, and phosphoric acid so that the coating amount of chromium is 10 mg / m ² (dry mass). The coating was performed on both surfaces of the aluminum foil by the method and baked for 20 seconds under the condition that the film temperature was 180 ° C. or higher. The thickness of the acid-resistant film formed on both surfaces of the aluminum foil was 5 nm, respectively.

Next, the resin composition containing the main agent and the curing agent described in Table 1 was applied to the other surface of the barrier layer of the obtained laminate so that the application amount (dry mass) described in Table 1 was obtained. And dried at 80 ° C. for 60 seconds to form a cured resin layer. Next, from above the cured resin layer, a polypropylene film (thickness 35 μm) was laminated by a dry lamination method to form a heat-fusible resin layer. Through the above steps, a laminate including a base material layer, an adhesive layer, a barrier layer, a cured resin layer, and a heat-fusible resin layer was obtained in this order. In addition, from the viewpoint of improving the moldability of the battery packaging material, erucic acid amide was present as a lubricant on the innermost layer side (the side opposite to the barrier layer) of the unstretched polypropylene film. Next, each of the obtained laminates was aged in a 70 ° C. environment for 24 hours to obtain battery packaging materials of Examples 1 to 6 and Comparative Examples 1 to 4. In addition, Table 1 shows the thickness of the cured resin layer converted from the coating amount and density. MDI in Table 1 is diphenylmethane diisocyanate.

<Example 6>
A battery packaging material was obtained in the same manner as in Example 1 except that stainless steel foil (austenitic stainless steel foil, thickness 20 μm) was used as the barrier layer instead of aluminum foil.

<Comparative example 4>
A battery packaging material was obtained in the same manner as in Comparative Example 1 except that stainless steel foil (austenitic stainless steel foil, thickness 20 μm) was used as the barrier layer instead of aluminum foil.

<10-point average roughness of the surface of the heat-fusible resin layer>
With respect to the surface of the heat-fusible resin layer of each battery packaging material obtained in Examples 1 to 6, the ten-point average roughness was measured by a method in accordance with JIS B0601: 1994. The measurement was performed using a Keyence laser microscope VK-9710 under the measurement conditions of an objective lens 50 times and no cutoff. As a result, the ten-point average roughness was 1.1 μm in Examples 1, 2, and 4, and 1.2 μm in Examples 3, 5, and 6.

<Thermo-mechanical analysis to measure probe displacement>
A probe is placed on the surface of the cured resin layer in the cross section of each battery packaging material obtained above (probe tip radius is 30 nm or less, probe deflection is set to -4V), and the probe is 40 ° C. To 250 ° C. (heating rate 5 ° C./min), and the displacement of the probe was measured. The results are shown in Table 1. Moreover, the graph which shows the relationship between heating temperature and the displacement of the position of a probe is shown in FIG. 8 (Example 3) and FIG. 9 (comparative example 3), respectively. Details of the measurement conditions are as follows. An afm plus system manufactured by ANASIS INSTRUMENTS was used as a thermomechanical analysis apparatus, and a cantilever ThermoLever AN2-200 (spring constant 0.5-3 N / m) was used as a probe. For calibration, three types of attached samples (polycaprolactam (melting peak temperature 55 ° C.), polyethylene (melting peak temperature 116 ° C.), polyethylene terephthalate (melting peak temperature 235 ° C.)) were used, and the applied voltage was 0.1-10 V The speed was 0.2 V / sec, and the set value of the deflection was -4V. The displacement of the position (Defection (V)) represents the position (warp) of the probe tip, and the larger the value, the higher the probe tip is (the probe is warped upward). For the probe displacement measurement, cross sections along the TD and the thickness direction were prepared for the battery packaging material, and measurements were taken at five locations on the cross section (see FIG. 10), and an average value was adopted. In addition, calibration was performed 5 times, and an average value was adopted.

In addition, for each battery packaging material, the amount of increase in the probe position when heating from 140 ° C. to 220 ° C. (Defection (V)) and the amount of increase in the position of the probe when heated from 80 ° C. to 120 ° C. ( Definition (V)) is shown in Table 2.

<Durability evaluation>
Each battery packaging material obtained above was cut into 60 mm (MD (Machine Direction)) × 150 mm (TD (Transverse Direction)) as shown in the schematic diagram of FIG. 6 (FIG. 6A). . Next, the cut battery packaging material was folded in half so that the heat-fusible resin layers face each other in TD (FIG. 6B). Next, one side E opposite to the TD and one side F of the MD were heat-sealed (the width of the heat-sealed portion S was 7 mm) to produce a bag-shaped battery packaging material in which one side of the TD opened. (FIG. 6 (c) opening G). The heat sealing conditions were a temperature of 190 ° C., a surface pressure of 1.0 MPa, and a heating / pressurization time of 3 seconds. Next, as shown in FIG. 6D, 3 g of the electrolytic solution H was injected from the opening G. Next, the opening G was 7 mm wide and heat-sealed under the same conditions as above (FIG. 6 (e)). The electrolytic solution H was obtained by mixing lithium hexafluorophosphate with a solution mixed at a volume ratio of ethylene carbonate: diethyl carbonate: dimethyl carbonate = 1: 1: 1. Next, the portion where the opening G of the battery packaging material was located was faced up (state shown in FIG. 6 (e)) and left in a constant temperature layer at 85 ° C. for 24 hours. For the MD and TD of the battery packaging material, for example, the rolling direction of the aluminum foil constituting the barrier layer is MD, and the direction perpendicular to the same plane as MD is TD. The rolling direction of the aluminum foil can be confirmed by the rolling trace of the aluminum foil.

Next, each battery packaging material is taken out from the thermostatic layer, and as shown in FIG. 6 (f), the side into which the electrolyte H has been injected is cut out (the position of the two-dot chain line in FIG. 6 (f)). The packaging material was opened and the electrolytic solution H was taken out (FIG. 6 (g)). Next, a TD width W15 mm portion of the battery packaging material was cut into a strip shape (two-dot chain line portion in FIG. 6H) to obtain a test piece T (FIG. 6I). The obtained heat-sealable resin layer and the barrier layer of the test piece T were peeled off, and the heat-sealable resin layer and the barrier layer were separated by 50 mm using a tensile tester (trade name AGS-XPlus manufactured by Shimadzu Corporation). The sample was pulled at a rate of / min and the peel strength (N / 15 mm) of the test piece was measured (peel strength after the durability test). On the other hand, the 180-degree peel strength was measured in the same manner for the test piece T obtained by cutting the battery packaging materials obtained in Examples 1 to 6 and Comparative Examples 1 to 4 into a width of MD15 mm × TD40 mm (before the durability test). Peel strength). The results are shown in Table 1. The measured value is an average value of N = 3. The peel strength of the test piece was measured in an environment at a temperature of 25 ° C. and a relative humidity of 50%. When the heat-fusible resin layer and the barrier layer are peeled off, the cured resin layer located between these layers is in a state of being laminated on either or both of the heat-fusible resin layer and the barrier layer. Become.

<Insulation evaluation against foreign object biting>
As shown in the schematic diagram of FIG. 7, each battery packaging material obtained above was cut into a size of 60 mm (TD) × 150 mm (MD) to obtain a test piece (FIG. 7A). Next, this test piece was folded so that the short sides were opposed to each other, and the test pieces were arranged so that the surfaces of the heat-fusible resin layers of the test pieces faced each other. Next, a wire M having a diameter of 25 μm was inserted between the surfaces of the heat-fusible resin layers facing each other (FIG. 7B). Next, in this state, the heat-fusible resin layers are heat-sealed with a heat-sealing machine composed of a flat plate-like hot plate having a width of 7 mm in both the upper and lower directions in the direction perpendicular to the length direction of the battery packaging material (temperature 190 ° C., surface The pressure was 1.0 MPa, and the heating / pressurizing time was 3 seconds) (FIG. 7C, heat-sealed portion S). At this time, heat sealing was performed from above the portion where the wire M is located, and the heat-fusible resin layer was heat-sealed to the wire M. Next, the positive electrode of the tester was connected to the wire M, and the negative electrode was connected to the battery packaging material on one side. At this time, for the negative pole of the tester, the alligator clip was sandwiched so as to reach the aluminum layer from the base material layer side of the electrical packaging material, and the negative pole of the tester and the aluminum foil were electrically connected. Next, a voltage of 100 V was applied between the testers, and the time (seconds) until short-circuiting was measured. The results are shown in Table 1.

In Table 1, when measuring the displacement amount of the probe, when the probe was heated from 40 ° C. to 220 ° C., the case where the probe position did not decrease from the initial value was indicated as A, and the case where the probe position was reduced was expressed as C.

As shown in Table 1, in the battery packaging materials obtained in Examples 1 to 6, in the thermomechanical analysis for measuring the displacement amount of the probe of the cured resin layer, the set value of the deflection of the probe at the start of the measurement When the probe was heated from 40 ° C. to 220 ° C. under the conditions of −4 V and a temperature increase rate of 5 ° C./min, the position of the probe was not lowered from the initial value. On the other hand, in the battery packaging materials obtained in Comparative Examples 1 to 4, in the thermomechanical analysis for measuring the displacement of the probe, when the probe was heated from 40 ° C. to 220 ° C., the probe position was higher than the initial value. It was falling.

* 1: The probe position is lower than that at 80 ° C. at a temperature of 120 ° C. or lower.
* 2: The position of the probe is lower at a temperature of 220 ° C. or lower than at 140 ° C.

DESCRIPTION OF SYMBOLS 1 ... Base material layer 2 ... Adhesive layer 3 ... Barrier layer 4 ... Hardened resin layer 4a Probe installation position 5 ... Thermal-fusion-bonding resin layer 10 ... Probe

Claims

It is composed of a laminate including at least a base material layer, a barrier layer, a cured resin layer, and a heat-fusible resin layer in this order,
In the thermomechanical analysis for measuring the displacement of the probe, the probe is set on the surface of the cured resin layer in the cross section of the laminate, and the set value of the deflection of the probe at the start of the measurement is −4 V, the heating rate is 5 A battery packaging material in which, when the probe is heated from 40 ° C. to 220 ° C. under the condition of ° C./min, the position of the probe does not fall below the initial value.
In the thermomechanical analysis for measuring the displacement of the probe, the probe is set on the surface of the cured resin layer in the cross section of the laminate, and the set value of the deflection of the probe at the start of the measurement is −4 V, the heating rate is 5 When the probe was heated from 40 ° C. to 220 ° C. under the condition of ° C./min, the amount of increase in the position of the probe when heated from 140 ° C. to 220 ° C. was when heated from 80 ° C. to 120 ° C. The battery packaging material according to claim 1, wherein the battery packaging material is larger than a rising amount of the position of the probe.
The battery packaging material according to claim 1 or 2, wherein the cured resin layer is a cured product of a resin composition containing an acid-modified polyolefin.
The acid-modified polyolefin of the cured resin layer is maleic anhydride-modified polypropylene,
The battery packaging material according to claim 3, wherein the heat-fusible resin layer contains polypropylene.
The battery packaging material according to any one of claims 1 to 4, wherein the resin constituting the cured resin layer includes a polyolefin skeleton.
The cured resin layer 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, an epoxy resin, and a urethane resin. The battery packaging material according to any one of the above.
The cured resin layer is a cured product of a resin composition containing a curing agent having 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. Item 7. The battery packaging material according to any one of Items 1 to 6.
The battery packaging material according to any one of claims 1 to 6, wherein the cured resin layer contains at least one selected from the group consisting of urethane resins, ester resins, and epoxy resins.
The battery packaging material according to any one of claims 1 to 8, wherein the thickness of the cured resin layer is 0.6 µm or more and 11 µm or less.
The battery packaging material according to any one of claims 1 to 9, wherein a softening temperature of the cured resin layer is in a range of 180 ° C or higher and 260 ° C or lower.
The battery packaging material according to any one of claims 1 to 10, wherein the heat-fusible resin layer has a thickness in the range of 10 µm to 40 µm.
The battery packaging material according to any one of claims 1 to 11, wherein the heat-fusible resin layer has fine irregularities on a surface thereof.
At least a layering step of obtaining a laminate including a base material layer, a barrier layer, a cured resin layer, and a heat-fusible resin layer in this order;
In the thermomechanical analysis for measuring the displacement of the probe, the probe is installed on the surface of the cured resin layer at the end of the laminate, and the deflection setting value of the probe at the start of measurement is −4 V, the heating rate A method for producing a packaging material for a battery, wherein a material in which the position of the probe does not lower than an initial value when the probe is heated from 40 ° C. to 220 ° C. under a condition of 5 ° C./min is used as the cured resin layer.