JP7151484B2 - BATTERY PACKAGING MATERIAL, MANUFACTURING METHOD THEREOF, AND BATTERY - Google Patents

Description

TECHNICAL FIELD The present invention relates to a battery packaging material, a manufacturing method thereof, and a battery.

Conventionally, various types of batteries have been developed. In these batteries, battery elements composed of electrodes, electrolytes and the like need to be sealed with a packaging material or the like. Metal packaging materials are often used as battery packaging materials.

In recent years, with the increasing performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, and the like, batteries having various shapes are required. In addition, batteries are required to be thinner and lighter. However, it is difficult to keep up with the diversification of battery shapes with conventionally widely used metal packaging materials. Moreover, since it is made of metal, there is a limit to reducing the weight of the packaging material.

Therefore, as a packaging material for batteries that can be easily processed into various shapes and that can realize thinness and weight reduction, a film-like laminate in which a substrate layer/barrier layer/heat-fusible resin layer is sequentially laminated has been developed. Proposed.

Patent Document 1 discloses a substrate layer, an adhesive layer, an aluminum foil layer provided with a corrosion prevention treatment layer, an adhesive resin layer, and a sealant layer provided on the opposite side of the adhesive resin layer to the substrate layer. are sequentially laminated, and the adhesive resin layer contains an acid-modified polyolefin resin and an elastomer.

JP 2013-258162 A

However, as a result of intensive studies by the present inventors, the battery packaging material disclosed in Patent Document 1 may have reduced insulating properties and durability when the battery packaging material is applied to a battery. problem was found.

Therefore, as a result of further intensive studies by the present inventors, it was found that minute foreign substances such as fragments of the electrode active material and electrode tabs sometimes adhere to the surface of the heat-fusible resin layer in the manufacturing process of the battery. It has been found that the heat and pressure applied when the battery element is heat-sealed with the battery packaging material sometimes causes the portion of the heat-fusible resin layer to which the foreign matter adheres to become thin. For example, if the heat-fusible resin layer becomes thin in a portion where the heat-fusible resin layers are heat-sealed together, there is a problem that the insulation and durability of the battery packaging material may become insufficient. be.

Furthermore, minute foreign matter such as fragments of the electrode active material and electrode tabs are electrically conductive. If there is a conductive foreign matter between the electrode tab and the heat-sealable resin layer, the foreign matter will penetrate the heat-sealable resin layer due to the heat and pressure during heat sealing. The barrier layer of the packaging material may be electrically connected to cause a short circuit.

The present invention is an invention 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 inventor of the present invention has made earnest studies to solve the above problems. As a result, a thermomechanical analysis was performed to measure the amount of displacement of the probe by forming the battery packaging material from a laminate comprising a substrate layer, a barrier layer, a cured resin layer, and a heat-fusible resin layer in this order. In, a probe is installed on the surface of the cured resin layer in the cross section of the battery packaging material (the laminate), and the set value of the deflection of the probe at the start of measurement is -4 V, and the temperature increase rate is 5 ° C./min. It was found that when the probe was heated from 40° C. to 220° C. under the above conditions, the position of the probe did not decrease below the initial value, thereby obtaining a highly insulating and durable battery packaging material.

The present invention is an invention completed by further studies based on these findings. That is, the present invention provides inventions in the following aspects.
Section 1. At least, it is composed of 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 amount of displacement of the probe, the probe is installed 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 measurement is -4 V and the temperature rise rate is 5. A packaging material for a battery, wherein the position of the probe does not decrease below the initial value when the probe is heated from 40°C to 220°C under the condition of °C/min.
Section 2. In the thermomechanical analysis for measuring the amount of displacement of the probe, the probe is installed 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 measurement is -4 V and the temperature rise rate is 5. When the probe is heated from 40 ° C. to 220 ° C. under the conditions of ° C./min, the amount of rise in the position of the probe when heated from 140 ° C. to 220 ° C. is the same as that when heated from 80 ° C. to 120 ° C. Item 2. The battery packaging material according to item 1, wherein the amount of elevation of the position of the probe is larger than that 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.
Section 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. Items 1 to 5, wherein 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. Item, wherein 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 cured resin layer has a thickness of 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 the softening temperature of the cured resin layer is in the 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 heat-fusible resin layer has a thickness in the range of 10 μm or more and 40 μm or less.
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 its surface.
Item 13. A lamination step of obtaining a laminate comprising at least a substrate layer, a barrier layer, a cured resin layer, and a heat-fusible resin layer in this order,
In thermomechanical analysis for measuring the amount of displacement of the probe, the probe is installed on the surface of the cured resin layer at the end of the laminate, and the set value of the deflection of the probe at the start of measurement is -4 V, the temperature increase rate A method for producing a battery packaging material, wherein the cured resin layer does not lower the position of the probe than the initial value when the probe is heated from 40° C. to 220° C. under the condition of 5° C./min.

According to the battery packaging material of the present invention, it is possible to provide a battery packaging material having high insulation and durability. 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.

1 is a schematic cross-sectional view of an example of a battery packaging material according to the present invention; FIG. 1 is a schematic cross-sectional view of an example of a battery packaging material according to the present invention; FIG. 1 is a schematic cross-sectional view of an example of a battery packaging material according to the present invention; FIG. FIG. 2 is an example of a cross-sectional structure of a battery packaging material, and is a view for showing a position (adhesive layer surface of a cross section of the battery packaging material) where a probe is installed in thermomechanical analysis for measuring the amount of displacement of the probe. FIG. 2 is a conceptual diagram of positional change of a probe in thermomechanical analysis that measures the amount of displacement of the probe; It is a schematic diagram for demonstrating the method of the "durability evaluation" in an Example. It is a schematic diagram for demonstrating the method of "insulation evaluation with respect to a foreign material entrapment" in an Example. A probe is placed on the cured resin layer surface of the cross section of the battery packaging material obtained in Example 3, and the probe is heated from 40°C to 250°C. graph. A probe is placed on the cured resin layer surface of the cross section of the battery packaging material obtained in Comparative Example 3, and the probe is heated from 40° C. to 250° C. The relationship between the heating temperature and the positional displacement of the probe is shown. graph. FIG. 4 is a schematic perspective view showing positions (five places) where probes are installed in thermomechanical analysis for measuring the amount of displacement of the probe.

In the present invention, the battery packaging material is composed of a laminate comprising at least a substrate layer, a barrier layer, a cured resin layer, and a heat-fusible resin layer in this order, and the amount of displacement of the probe is In the thermomechanical analysis to be measured, a probe is installed on the surface of the cured resin layer in the cross section of the laminate, and the deflection setting value of the probe at the start of measurement is -4 V, and the temperature rise rate is 5 ° C./min. is heated from 40° C. to 220° C., the position of the probe does not decrease from the initial value. Hereinafter, the battery packaging material of the present invention, the method for producing the same, 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, regarding numerical ranges, the numerical range indicated by "-" means "more than" and "less than". For example, the notation of 2 to 15 mm means 2 mm or more and 15 mm or less.

1. Laminated structure of battery packaging material The battery packaging material of the present invention comprises, as shown in FIG. It consists of a laminate with In the battery packaging material of the present invention, the substrate layer 1 is the outermost layer, and the heat-fusible resin layer 5 is the innermost layer. That is, when the battery is assembled, the heat-sealable resin layers 5 positioned at the periphery of the battery element are heat-sealed to seal the battery element, thereby sealing the battery element.

As shown in FIG. 2, the battery packaging material of the present invention is provided with an adhesive layer 2 between the base material layer 1 and the barrier layer 3 for the purpose of enhancing adhesion between them, if necessary. good too. Further, as shown in FIG. 3 , a surface coating layer 6 may be provided on the surface of the substrate 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. 160 μm or less, more preferably about 35 to 155 μm, 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, for example, 160 μm or less, the present invention can exhibit excellent insulating properties. Therefore, the battery packaging material of the present invention can contribute to improving the energy density of the battery.

2. Each layer forming the battery packaging material [base layer 1]
In the battery packaging material of the present invention, the substrate layer 1 is the outermost layer. The material forming the base material layer 1 is not particularly limited as long as it has insulating properties. Materials for forming the substrate layer 1 include, for example, polyester resins, polyamide resins, epoxy resins, acrylic resins, fluorine resins, polyurethane resins, silicone resins, phenolic resins, and resin films such as mixtures and copolymers thereof. mentioned. Moreover, the base material layer 1 may be formed by applying a resin. Among these, polyester resins and polyamide resins are preferred, and biaxially stretched polyester resins and biaxially stretched polyamide resins are more preferred. Specific examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolymerized polyester, polycarbonate and the like. Specific examples of polyamide resins include nylon 6, nylon 66, copolymers of nylon 6 and nylon 66, nylon 6,10, and polymeta-xylylene adipamide (MXD6).

The substrate layer 1 may be formed of a single layer of resin film, but may be formed of two or more layers of resin film 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, a multilayer structure in which a plurality of polyester films are laminated, and the like. When the substrate 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. body is preferred. For example, when the base material layer 1 is formed from two layers of resin films, a structure in which a polyester resin and a polyester resin are laminated, a structure in which a polyamide resin and a polyamide resin are laminated, or a structure in which a polyester resin and a polyamide resin are laminated. is preferred, and 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 is more preferred. In addition, since the polyester resin does not easily discolor when the electrolytic solution adheres to the surface, it is preferable to laminate the base material layer 1 so that the polyester resin is positioned as the outermost layer in the laminate structure. When the substrate layer 1 has a multilayer structure, the thickness of each layer is preferably about 2 to 25 μm.

When the substrate 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. are the same as those for the adhesive layer 2, which will be described later. The method for laminating two or more layers of resin films is not particularly limited, and known methods can be employed, such as a dry lamination method and a sandwich lamination method, preferably a dry lamination method. When laminating by a dry lamination method, it is preferable to use a polyurethane-based 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, a lubricant is preferably present on the surface of the substrate layer 1 from the viewpoint of improving the moldability of the battery packaging material. The lubricant is not particularly limited, but preferably includes an amide-based lubricant. Specific examples of amide-based lubricants include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylolamides, saturated fatty acid bisamides, and unsaturated fatty acid bisamides. Specific examples of saturated fatty acid amides include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide. Specific examples of unsaturated fatty acid amides include oleic acid amide and erucic acid amide. Specific examples of substituted amides 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. Further, specific examples of methylolamide include methylol stearamide. Specific examples of saturated fatty acid bisamides include methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, ethylenebisstearic acid amide, ethylenebishydroxystearic acid amide, ethylenebisbehenic acid amide, hexamethylenebisstearin. acid amide, hexamethylenebisbehenamide, hexamethylenehydroxystearic acid amide, N,N'-distearyladipic acid amide, N,N'-distearylsebacic acid amide and the like. Specific examples of unsaturated fatty acid bisamides include ethylenebisoleic acid amide, ethylenebiserucic acid amide, hexamethylenebisoleic acid amide, N,N'-dioleyladipic acid amide, and N,N'-dioleylsebacic acid amide. etc. Specific examples of fatty acid ester amides include stearamide ethyl stearate. Further, specific examples of the aromatic bisamide include m-xylylenebisstearic acid amide, m-xylylenebishydroxystearic acid amide, N,N'-distearyl isophthalic acid amide and the like. Lubricants may be used singly or in combination of two or more.

When a lubricant exists on the surface of the base material layer 1, its amount is not particularly limited, but in an environment of temperature 24° C. and humidity 60%, it is preferably about 3 mg/m ² or more, more preferably 4 to 15 mg/m 2 . 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 exuding the lubricant contained in the resin constituting the base material layer 1, or by coating the surface of the base material layer 1 with the lubricant. may be

The thickness of the base material layer 1 is not particularly limited as long as it functions as a base material layer.

[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 made of an adhesive capable of bonding the base material layer 1 and the barrier layer 3 together. The adhesive used to form the adhesive layer 2 may be a two-component curing adhesive or a one-component curing adhesive. Furthermore, the adhesive used to form the adhesive layer 2 is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a hot melt 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-based resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyester; Polyurethane adhesive; Epoxy resin; Phenolic resin; Polyamide resin such as nylon 6, nylon 66, nylon 12, copolyamide; Polyolefin such as polyolefin, carboxylic acid-modified polyolefin, metal-modified polyolefin Resins, polyvinyl acetate resins; cellulose adhesives; (meth)acrylic resins; polyimide resins; polycarbonates; amino resins such as urea resins and melamine resins; Examples include silicone-based resins. These adhesive components may be used singly or in combination of two or more. Among these adhesive components, polyurethane-based adhesives are preferred.

As the polyurethane adhesive, for example, a polyurethane adhesive containing a main agent containing a polyol component (A) and a curing agent containing a polyisocyanate component (B), wherein the polyol component (A) is a polyester A polyester polyol containing a polyol (A1), wherein the polyester polyol (A1) is composed of a polybasic acid component and a polyhydric alcohol component and has a number average molecular weight of 5000 to 50000, wherein 100 mol% of the polybasic acid component Examples include those containing 45 to 95 mol % of an aromatic polybasic acid component and having a tensile stress of 100 kg/cm ² or more and 500 kg/cm ² or less when the adhesive layer is stretched 100%. Further, for example, a polyurethane-based adhesive for battery packaging 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 higher and 5 to 50% by weight of glass A polyol component (A) containing 95 to 50% by weight of a polyester polyol (A2) having a transition temperature of less than 40° C. and a silane coupling agent (B), wherein the sum of hydroxyl groups and carboxyl groups derived from the polyol component (A) The equivalent ratio [NCO]/([OH]+[COOH]) of the isocyanate group contained in the curing agent to the curing agent is 1 to 30.

Moreover, the adhesive layer 2 may contain a coloring agent. Since the adhesive layer 2 contains a coloring agent, the battery packaging material can be colored. Known substances such as pigments and dyes can be used as the colorant. In addition, only one type of colorant may be used, or two or more types may be mixed and used.

For example, specific examples of inorganic pigments preferably include carbon black and titanium oxide. Further, specific examples of organic pigments preferably include azo pigments, phthalocyanine pigments, condensed polycyclic pigments, and the like. Examples of azo pigments include soluble pigments such as Watching Red and Chikamine 6C; insoluble azo pigments such as monoazo yellow, disazo yellow, pyrazolone orange, pyrazolone red, and permanent red; and phthalocyanine pigments include copper phthalocyanine pigments. , metal-free phthalocyanine pigments such as blue pigments and green pigments, and condensed polycyclic pigments such as dioxazine violet and quinacridone violet. Pearl pigments and fluorescent pigments can also be used as pigments.

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

The average particle size of the pigment is not particularly limited, and is, for example, approximately 0.05 to 5 μm, preferably approximately 0.08 to 2 μm. The average particle size of the pigment is the median size measured with a laser diffraction/scattering particle size distribution analyzer.

The content of the pigment in the adhesive layer 2 is not particularly limited as long as the battery packaging material is colored, and is, for example, 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.

[Colored layer]
The colored layer is a layer provided as necessary between the base layer 1 and the adhesive layer 2 (not shown). By providing the colored layer, the battery packaging material can be colored.

The colored layer can be formed, for example, by applying ink containing a coloring agent to the surface of the base material layer 1 or the surface of the barrier layer 3 . Known substances such as pigments and dyes can be used as the colorant. In addition, only one type of colorant may be used, or two or more types may be mixed and used.

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

[Barrier layer 3]
In the battery packaging material, the barrier layer 3 is a layer that has the function of improving the strength of the battery packaging material and also preventing water vapor, oxygen, light, etc. from entering the battery. The barrier layer 3 can be formed of a metal foil, a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, a film provided with these vapor deposition layers, or the like. Preferably. Specific examples of the metal forming the barrier layer 3 include aluminum, stainless steel, titanium steel, and the like, preferably aluminum. The barrier layer 3 can be formed of, for example, a metal foil, a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, a film provided with these vapor deposition films, or the like. is preferred, and forming from an aluminum foil or a stainless steel foil is more preferred. From the viewpoint of preventing wrinkles and pinholes in the barrier layer 3 during 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).

Examples of 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, etc. 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 against water vapor. 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, even more preferably about 40 μm or less, further preferably about 30 μm or less. , Particularly preferably about 25 μm or less, 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 40 μm. About 10 to 30 μm, more preferably about 15 to 25 μm.

At least one surface, preferably both surfaces, of the barrier layer 3 is preferably subjected to a chemical conversion treatment in order to stabilize adhesion and prevent dissolution and corrosion. Here, chemical conversion treatment refers to 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 the acid-resistant film. Examples of chemical conversion treatments include chromate chromate using chromate compounds such as chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, chromate acetyl acetate, chromium chloride, and potassium chromium sulfate. Treatment; phosphate chromate treatment using a phosphoric acid compound such as sodium phosphate, potassium phosphate, ammonium phosphate, polyphosphoric acid; aminated phenol having repeating units represented by the following general formulas (1) to (4) Chromate treatment using a polymer and the like can be mentioned. 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. good too.

In general formulas (1) to (4), X represents a hydrogen atom, hydroxyl group, alkyl group, hydroxyalkyl group, allyl group or benzyl group. R ¹ and R ² are the same or different and represent a hydroxyl group, an alkyl group or a hydroxyalkyl group. Examples of alkyl groups represented by X, R ¹ and R ² in general formulas (1) to (4) include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, A linear or branched alkyl group having 1 to 4 carbon atoms such as a tert-butyl group can be mentioned. Examples of hydroxyalkyl groups represented by X, R ¹ and R ² include hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 1-hydroxypropyl group, 2-hydroxypropyl group, 3- straight or branched chain having 1 to 4 carbon atoms substituted with one hydroxyl group such as hydroxypropyl group, 1-hydroxybutyl group, 2-hydroxybutyl group, 3-hydroxybutyl group and 4-hydroxybutyl group; An alkyl group is mentioned. In general formulas (1) to (4), the alkyl groups and hydroxyalkyl groups represented by X, R ¹ and R ² may be the same or different. In 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 repeating units represented by formulas (1) to (4) is, for example, preferably about 500 to 1,000,000, more preferably about 1,000 to 20,000. more preferred.

In addition, as a chemical conversion treatment method for imparting corrosion resistance to the barrier layer 3, fine particles of metal oxides such as aluminum oxide, titanium oxide, cerium oxide, and tin oxide, and barium sulfate are dispersed in phosphoric acid. 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. A resin layer obtained by cross-linking a cationic polymer with a cross-linking agent may be further formed on the acid-resistant film. Examples of the cationic polymer include polyethyleneimine, an ionic polymer complex composed of a polymer containing polyethyleneimine and carboxylic acid, a primary amine-grafted acrylic resin obtained by graft-polymerizing a primary amine to an acrylic backbone, and polyallylamine. or derivatives thereof, aminophenol and the like. As these cationic polymers, only one type may be used, or two or more types may be used in combination. Examples of cross-linking agents include compounds having at least one functional group selected from the group consisting of isocyanate groups, glycidyl groups, carboxyl groups, and oxazoline groups, and silane coupling agents. As these cross-linking agents, only one type may be used, or two or more types may be used in combination.

As a specific method for providing an acid-resistant coating, for example, at least the inner layer side surface of an aluminum foil (barrier layer) is first subjected to an alkali immersion method, an electrolytic cleaning method, an acid cleaning method, or an electrolysis method. A degreasing treatment is performed by a well-known treatment method such as an acid cleaning method or an acid activation method, and then the degreased surface is coated with Cr (chromium) phosphate, Ti (titanium) phosphate, Zr (zirconium) phosphate, and phosphorus. A treatment liquid (aqueous solution) mainly composed of a metal phosphate salt such as Zn (zinc) acid salt and a mixture of these metal salts, or a non-metal phosphate and a mixture of these non-metal salts as a main component A treatment solution (aqueous solution), or a treatment solution (aqueous solution) consisting of a mixture of these and a water-based synthetic resin such as an acrylic resin, a phenolic resin, or a polyurethane resin is applied by a roll coating method, a gravure printing method, an immersion method, etc. An acid-resistant film can be formed by coating with a known coating method. For example, when treated with a Cr (chromium) phosphate salt-based treatment solution, CrPO ₄ (chromium phosphate), AlPO ₄ (aluminum phosphate), Al ₂ O ₃ (aluminum oxide), Al(OH) _x (water aluminum oxide), AlF _x (aluminum fluoride), etc., and when treated with a Zn (zinc) phosphate salt-based treatment solution, Zn ₂ PO ₄ 4H ₂ O (zinc phosphate hydrate ), AlPO ₄ (aluminum phosphate), Al ₂ O ₃ (aluminum oxide), Al(OH) _x (aluminum hydroxide), AlF _x (aluminum fluoride), and the like.

Further, as other specific examples of the method for providing the acid-resistant film, for example, at least the inner layer side surface of the aluminum foil is first subjected to an alkali immersion method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, an acid activated An acid-resistant film can be formed by performing a degreasing treatment by a well-known treatment method such as a degreasing method, and then subjecting the degreased surface to a well-known anodizing treatment.

Another example of the acid-resistant coating includes a coating of a phosphorus compound (eg, phosphate-based) and a chromium compound (eg, chromic acid-based). Phosphate type includes zinc phosphate, iron phosphate, manganese phosphate, calcium phosphate, chromium phosphate and the like, and chromic acid type includes chromium chromate and the like.

In addition, as another example of the acid-resistant film, by forming an acid-resistant film of phosphorus compounds (phosphates, etc.), chromium compounds (chromates, etc.), fluorides, triazine thiol compounds, etc., Prevention of delamination between the aluminum and the base material layer, dissolution and corrosion of the aluminum surface, especially aluminum oxide present on the aluminum surface, due to the hydrogen fluoride generated by the reaction between the electrolyte and moisture. and improve the adhesion (wettability) of the aluminum surface, prevent delamination between the base layer and aluminum during heat sealing, and delamination between the base layer and aluminum during press molding for embossed types. It shows the effect of preventing lamination. Among the substances that form an acid-resistant film, an aqueous solution composed of three components, phenolic resin, chromium (3) fluoride compound, and phosphoric acid, is applied to the surface of aluminum, followed by dry baking.

Further, the acid-resistant film includes a layer having cerium oxide, phosphoric acid or a phosphate, an anionic polymer, and a cross-linking agent that cross-links the anionic polymer, and the phosphoric acid or phosphate is the It may be blended in an amount of 1 to 100 parts by mass with respect to 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 cross-linking agent for cross-linking the cationic polymer.

Furthermore, the anionic polymer is preferably poly(meth)acrylic acid or a salt thereof, or a copolymer containing (meth)acrylic acid or a salt thereof as a main component. Moreover, the cross-linking agent is preferably at least one selected from the group consisting of a compound having a functional group such as an isocyanate group, a glycidyl group, a carboxyl group, or an oxazoline group, and a silane coupling agent.

Further, the phosphoric acid or phosphate is preferably condensed phosphoric acid or condensed phosphate.

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

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

Further, specific examples of acid-resistant coatings include phosphate-based coatings, chromate-based coatings, fluoride-based coatings, and triazinethiol compound coatings. The acid-resistant coating may be one of these, or may be a combination of multiple types. Furthermore, as the acid-resistant film, after degreasing the chemically treated surface of the barrier layer, It may be formed of a different treatment liquid.

The composition of the acid-resistant coating 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. 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 of the phosphorus compound, and 1.0 mg of aminated phenolic polymer. It is desired to be contained in a ratio of about 0 to 200 mg, preferably about 5.0 to 150 mg.

The thickness of the acid-resistant coating 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 cohesion of the coating and adhesion to the barrier layer and the heat-sealable resin layer. , and more preferably about 1 nm to 50 nm. The thickness of the acid-resistant film can be measured by observation with a transmission electron microscope, or by a combination of observation with a transmission electron microscope and energy dispersive X-ray spectroscopy or electron beam energy loss spectroscopy. By analysis of the composition of the acid-resistant film using time-of-flight secondary ion mass spectrometry, for example, secondary ions composed of Ce, P and O (for example, at least one of Ce ₂ PO ₄ ⁺ , CePO ₄ ⁻ ) and secondary ions composed of Cr, P, and O (eg, at least one of CrPO ₂ ⁺ and CrPO ₄ ⁻ ) are 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, an immersion method, or the like. It is carried out by heating to about 200°C. In addition, before the barrier layer is subjected to the chemical conversion treatment, the barrier layer may be previously subjected to a degreasing treatment by an alkali immersion method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, or the like. By performing the degreasing treatment in this way, it becomes possible to perform the chemical conversion treatment on the surface of the barrier layer more efficiently.

[Cured 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, the cured resin layer 4 is obtained by placing a probe on the cured resin layer surface of the cross section of the battery packaging material (laminate) in thermomechanical analysis for measuring the amount of displacement of the probe, and measuring the probe at the start of measurement. It is characterized in that when the probe is heated from 40° C. to 220° C. under the conditions of a deflection set value of −4 V and a heating rate of 5° C./min, the position of the probe does not fall below the initial value.

In the thermomechanical analysis for measuring the amount of displacement of the probe, first, as shown in the conceptual diagram of FIG. Install the probe 10 (measurement start A in FIG. 5). The cross section at this time is the exposed portion of the cross section of the cured resin layer 4 obtained by cutting in the thickness direction so as to pass through the central portion of the battery packaging material. Cutting can be performed using a commercially available rotating microtome or the like. When measuring the amount of displacement of the battery packaging material used for the battery containing the electrolyte, etc., the part where the heat-sealable resin layers of the battery packaging material are heat-sealed to each other should be measured. , take measurements. As an apparatus for thermomechanical analysis, an atomic force microscope to which a cantilever with a heating mechanism can be attached can be used. constant 0.5-3 N/m) can be used. The tip radius of the probe 10 is 30 nm or less, the deflection setting value of the probe 10 is -4 V, and the heating rate is 5° C./min. Next, when the probe is heated in this state, the surface of the cured resin layer 4 expands due to the heat from the probe, as shown in FIG. position) when the temperature is 40°C. When the temperature further rises, the cured resin layer 4 softens, and the probe 10 sticks into the cured resin layer 4 as shown in FIG. 5C, and the position of the probe 10 is lowered. In the thermomechanical analysis for measuring the amount of displacement of the probe, the battery packaging material to be measured is in a room temperature (25° C.) environment, and the probe heated to 40° C. is placed on the surface of the cured resin layer 4. , to start the measurement. To measure the amount of displacement of the probe, the battery packaging material is cross-sectioned along the thickness direction, measured at five locations on the cross-section (see FIG. 10), and the average value is used as the measured value. Note that the thickness direction and the vertical direction of the cross section may be in any direction (for example, TD), and the temperature at which the position of the probe decreases from the initial value in any direction should be 130 ° C. or less. . Also, the calibration is performed 5 times and the average value is adopted.

In the present invention, since the amount of 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 it becomes the battery packaging material), In comparison, it is possible to measure the thermal behavior of only the adhesive layer in a state close to that used in a battery. In other words, when the material of 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 measurement is 10 times or more thicker than the actual thickness of the adhesive layer. , the thermal behavior is different when actually used as a battery packaging material due to the difference in the degree of cure and bonding state. Moreover, in this case, the thermal behavior of the film substrate and the like may also have an influence, 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 insulation and durability, the set value of deflection of the probe at the start of measurement is -4 V, and the temperature rise rate is 5 ° C./min. When the is heated from 40 ° C. to 220 ° C., the position of the probe 10 installed on the surface of the cured resin layer 4 does not fall below the initial value (position when the temperature of the probe is 40 ° C.), and further, 160 ° C. It is more preferable that the position of the probe 10 placed on the surface of the cured resin layer 4 does not decrease when the temperature is heated from 200° C. to 200° C. The process of heat-sealing the heat-sealable resin layers of the battery packaging material to seal the battery element is usually performed by heating to about 160°C to 200°C. Therefore, when the probe is heated from 160° C. to 200° C., the battery packaging material that does not lower the position of the probe 10 placed on the surface of the cured resin layer 4 can exhibit particularly high insulation and durability. . From the viewpoint of further improving 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 furthermore, 160 ° C. It is more preferable that the position of the probe 10 placed on the surface of the cured resin layer 4 does not decrease when the temperature is heated from 200° C. to 200° C.

From a similar point of view, in the thermomechanical analysis for measuring the amount of 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 heated from 40°C to 220°C. When heated to ° C., the amount of increase in the position of the probe 10 when heated from 140 ° C. to 220 ° C. is preferably 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 more preferably large. Furthermore, the difference between the amount of rise in the position of the probe 10 when heated from 80 ° C. to 120 ° C. and the amount of rise in the position of the probe 10 when heated from 140 ° C. to 220 ° C. is preferably 0 V or more, 0 0.05V or higher, 0.1V or higher.

As described above, during the battery manufacturing process, minute foreign matter such as fragments of the electrode active material and electrode tabs may adhere to the surface of the heat-fusible resin layer, causing damage to the heat-fusible resin layer. A thin portion or a through hole may be generated, and the insulation may be deteriorated. On the other hand, the battery packaging material of the present invention has the above characteristics in thermomechanical analysis for measuring the amount of displacement of the probe 10. Even if minute foreign matter exists in the heat-sealed portion such as the interface between the heat-fusible resin layers or between the electrode tab and the heat-fusible resin layer, the insulating properties and durability of the battery packaging material will not be improved. is enhanced.

In the present invention, the cured resin layer 4 may 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 together and exhibiting high insulation and durability in the battery packaging material, the cured resin layer 4 is made of a resin composition containing an acid-modified polyolefin. is preferably a cured product of

In the present invention, as the acid-modified polyolefin, it is preferable to use a polyolefin modified with an unsaturated carboxylic acid or its acid anhydride. Furthermore, the acid-modified polyolefin may be further modified with a (meth)acrylate. The modified polyolefin further modified with a (meth)acrylic acid ester is obtained by acid-modifying a polyolefin using a combination of an unsaturated carboxylic acid or its acid anhydride and a (meth)acrylic acid ester. be. In the present invention, "(meth)acrylic acid ester" means "acrylic acid ester" or "methacrylic acid ester". Acid-modified polyolefin may be used individually by 1 type, and may be used in combination of 2 or more types.

The acid-modified polyolefin is not particularly limited as long as it is a resin containing at least an olefin as a monomer unit. Polyolefin can be composed of, for example, at least one of polyethylene and polypropylene, and is preferably composed of polypropylene. Polyethylene can be composed of, for example, homopolyethylene and/or ethylene copolymers. Polypropylene may be composed of, for example, homopolypropylene and/or propylene copolymers. Propylene copolymers include copolymers of propylene with other olefins such as ethylene-propylene copolymers, propylene-butene copolymers, ethylene-propylene-butene copolymers, and the like. The proportion of propylene units contained in polypropylene is preferably about 50 to 100 mol%, more preferably about 80 to 100 mol%, from the viewpoint of further enhancing the insulation and durability of the battery packaging material. . In addition, the ratio of ethylene units contained in 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. Ethylene copolymers and propylene copolymers can be either random copolymers or block copolymers, respectively. Also, the ethylene copolymer and propylene copolymer may be either crystalline or amorphous, and may be copolymers or mixtures thereof. Polyolefin may be formed from one type of homopolymer or copolymer, or may be formed from two or more types of homopolymers or copolymers.

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

Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid, and crotonic acid. As the acid anhydride, the acid anhydrides of the unsaturated carboxylic acids exemplified above are preferable, and maleic anhydride and itaconic anhydride are more preferable. The acid-modified polyolefin may be modified with one type of unsaturated carboxylic acid or its acid anhydride, or modified with two or more types of unsaturated carboxylic acids or their acid anhydrides. good too.

(Meth)acrylic acid esters include, for example, an ester of (meth)acrylic acid and an alcohol having 1 to 30 carbon atoms, preferably an ester of (meth)acrylic acid and an alcohol having 1 to 20 carbon atoms. is mentioned. Specific examples of (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, and (meth)acrylate. octyl acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, octyl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate and the like. Modification of polyolefin WHEREIN: Only one type of (meth)acrylic acid ester may be used, or two or more types may be used.

The proportion of the unsaturated carboxylic acid or its acid anhydride 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 battery packaging material can be further enhanced.

The proportion of the (meth)acrylic acid ester in the acid-modified polyolefin is preferably about 0.1 to 40% by mass, more preferably about 0.1 to 30% by mass. By setting it as such a range, the insulation and durability of the battery packaging material can be further enhanced.

The weight average molecular weights of the acid-modified polyolefins are preferably about 6,000 to 200,000, more preferably about 8,000 to 150,000. In the present invention, the weight average molecular weight of acid-modified polyolefin is a value measured by gel permeation chromatography (GPC) using polystyrene as a standard sample. Also, the melting peak temperature of the acid-modified polyolefin is preferably about 50 to 120.degree. C., more preferably about 50 to 100.degree. In the present invention, the melting peak temperature of acid-modified polyolefin refers to the endothermic peak temperature in differential scanning calorimetry.

In the acid-modified polyolefin, the method of modifying the polyolefin is not particularly limited. Examples of such copolymerization include random copolymerization, block copolymerization, graft copolymerization (graft modification), and the like, preferably graft copolymerization.

In addition, from the viewpoint of firmly bonding the barrier layer 3 and the heat-fusible resin layer 5 and making the battery packaging material exhibit high insulation and durability, the cured resin layer 4 is composed of 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. A cured product of the composition is more preferable. That is, the resin constituting the cured resin layer 4 may or may not contain a polyolefin skeleton, and preferably contains a polyolefin skeleton. Whether the resin constituting the cured resin layer 4 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography mass spectrometry, or the like, and the analysis method is not particularly limited. For example, when maleic anhydride-modified polyolefin is measured by infrared spectroscopy, peaks derived from maleic anhydride are detected near wavenumbers of 1760 cm ⁻¹ and 1780 cm ⁻¹ . However, if the degree of acid denaturation is low, the peak may be too small to be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy. The cured resin layer 4 preferably contains at least one selected from the group consisting of urethane resins, ester resins, and epoxy resins, and more preferably contains urethane resins and epoxy resins. As the ester resin, for example, an amide ester resin is preferable. Amide ester resins are generally produced by the reaction of carboxyl groups and oxazoline groups. More preferably, the cured resin layer 4 is a cured product of a resin composition containing at least one of these resins and the acid-modified polyolefin. In the case where unreacted products of a curing agent such as a compound having an isocyanate group, a compound having an oxazoline group, and an epoxy resin remain in the cured resin layer 4, the presence of the unreacted products can be detected by, for example, infrared spectroscopy. , Raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and the like.

Although the compound having an isocyanate group is not particularly limited, polyfunctional isocyanate compounds are preferred from the viewpoint of allowing the battery packaging material to exhibit high insulating properties and durability. The polyfunctional isocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of polyfunctional isocyanate curing agents include isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymers and nurates thereof, and Mixtures and copolymers with other polymers may be mentioned.

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, more preferably 1 to 12% by mass in the resin composition constituting the cured resin layer 4. A range is more preferred. Thereby, the insulation and durability of the battery packaging material can be further enhanced.

The compound having an oxazoline group is not particularly limited as long as it is a compound having an oxazoline skeleton. Specific examples of compounds 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, more preferably 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 enhanced.

The epoxy resin is not particularly limited as long as it is a resin capable of forming a crosslinked structure with epoxy groups present in the molecule, and known epoxy resins can be used. The weight average molecular weight of the epoxy resin is preferably about 50 to 2000, more preferably about 100 to 1000, 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) using polystyrene as a standard sample.

Specific examples of epoxy resins include bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolac glycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether, and the like. 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, more preferably in the range of 1 to 12% by mass, in the resin composition constituting the cured resin layer 4. is more preferred. Thereby, the insulation and durability of the battery packaging material can be further enhanced.

The urethane resin is not particularly limited, and known urethane resins can be used. The cured resin layer 4 may be, for example, a cured product of a two-liquid curing type 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, more preferably in the range of 1 to 15% by mass, in the resin composition constituting the cured resin layer 4. is more preferred. Thereby, the insulation and durability of the battery packaging material can be further enhanced. The cured resin layer 4 may be made of urethane resin.

In the present invention, the cured resin layer 4 is a resin composition containing at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and 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.

In addition, from the viewpoint of further increasing the adhesion between the barrier layer 3 (or the acid-resistant film), the heat-fusible resin layer 5, and the cured resin layer 4, the cured resin layer 4 contains oxygen atoms, heterocyclic rings, and C=N bonds. , and a C—O—C bond. The curing agent having a heterocyclic ring includes, for example, a curing agent having an oxazoline group, a curing agent having an epoxy group, and the like. Moreover, the curing agent having a C═N bond includes a curing agent having an oxazoline group, a curing agent having an isocyanate group, and the like. Further, the curing agent having a C—O—C bond includes a curing agent having an oxazoline group, a curing agent having an epoxy group, a urethane resin, and the like. The fact that the cured resin layer 4 is a cured product of a resin composition containing these curing agents can be achieved by, for example, gas chromatography mass spectrometry (GCMS), infrared spectroscopy (IR), time-of-flight secondary ion mass spectrometry ( TOF-SIMS), X-ray photoelectron spectroscopy (XPS), or the like.

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.degree. C. to 260.degree. C., more preferably about 200 to 240.degree. The softening temperature of the cured resin layer 4 is a value measured by a method conforming to the provisions of JIS K7196:2012 "Testing method for softening temperature by thermomechanical analysis of thermoplastic films and sheets". , are values measured by the method described in Examples.

Although the solid content of the cured resin layer 4 is not particularly limited, it is preferably about 0.5 to 10 g/m ² , more preferably 0.8 to 5.2 g, from the viewpoint of further improving insulation and durability. / m ² degree. From the same point of view, 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. The thickness of the cured resin layer 4 may be measured on a cross section obtained by cutting the laminate constituting the battery packaging material, or the thickness of the resin composition constituting the cured resin layer may be measured. It may be calculated from the amount and density, and any one of them may fall within these ranges.

[Heat-fusible 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 seals the battery element by heat-fusifying the heat-fusible resin layers to each other 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 is heat-fusible, and examples thereof include polyolefins and acid-modified polyolefins. That is, the resin forming the heat-fusible resin layer 5 may or may not contain a polyolefin skeleton, and preferably contains a polyolefin skeleton. Whether 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, or the like, and the analysis method is not particularly limited. For example, when maleic anhydride-modified polyolefin is measured by infrared spectroscopy, peaks derived from maleic anhydride are detected near wavenumbers of 1760 cm ⁻¹ and 1780 cm ⁻¹ . However, if the degree of acid denaturation is low, the peak may be too small to 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; polypropylene, such as random copolymers (eg, random copolymers of propylene and ethylene); terpolymers of ethylene-butene-propylene; Among these polyolefins, polyethylene and polypropylene are preferred, and polypropylene is more preferred.

The polyolefin may be a cyclic polyolefin. Cyclic polyolefins are copolymers of olefins and cyclic monomers. Examples of olefins that are constituent monomers of cyclic polyolefins include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, isoprene, and the like. be done. Examples of cyclic monomers constituting cyclic polyolefins include cyclic alkenes such as norbornene; specific examples thereof include cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene and norbornadiene. Among these polyolefins, cyclic alkenes are preferred, and norbornene is more preferred.

The acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of the above polyolefin with a carboxylic acid or the like. Carboxylic acids used for modification include, for example, maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride.

The acid-modified polyolefin may be an acid-modified cyclic polyolefin. Acid-modified cyclic polyolefin is obtained by copolymerizing a part of the monomers constituting the cyclic polyolefin with α,β-unsaturated carboxylic acid or its anhydride, or by adding α,β-unsaturated cyclic polyolefin. It is a polymer obtained by block polymerization or graft polymerization of saturated carboxylic acid or its anhydride. The acid-modified cyclic polyolefin is the same as described above. Carboxylic acids used for modification are the same as those used for modification of acid-modified cycloolefin copolymers.

Among these resin components, polyolefins are preferred; propylene copolymers are more preferred. Propylene copolymers include copolymers of propylene with other olefins such as ethylene-propylene copolymers, propylene-butene copolymers, ethylene-propylene-butene copolymers, and the like. The proportion of propylene units contained in polypropylene is preferably about 50 to 100 mol%, more preferably about 80 to 100 mol%, from the viewpoint of further enhancing the insulation and durability of the battery packaging material. . In addition, the ratio of ethylene units contained in 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. The ethylene copolymers and propylene copolymers may each be either random copolymers or block copolymers, with random propylene copolymers being preferred.

The heat-fusible resin layer 5 of the present invention preferably contains polypropylene, and preferably has a layer formed of polypropylene. The heat-fusible resin layer 5 may be formed of one resin component alone, or may be formed of a blend polymer in which two or more resin components are combined. Further, the heat-fusible resin layer 5 may be composed of only one layer, or may be composed of two or more layers of 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 of the heat-fusible resin layer 5 (the side opposite to the barrier layer 3) is formed by dry lamination or extrusion molding. It is preferably a single layer. This can further improve insulation and moldability.

The heat-fusible resin layer 5 of the present invention preferably has fine irregularities on its surface (surface on the innermost layer side). Thereby, moldability can be further improved. As a method for forming fine unevenness on the surface of the heat-fusible resin layer 5, there is a method of adding an additive exemplified in the surface coating layer 6 described later to the heat-fusible resin layer 5, and a method of forming the surface unevenness. A method of forming a mold by bringing a cooling roll having contact therewith, and the like. As the fine unevenness, 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, further preferably about 0.5 to 10 μm. About 2 μm can be mentioned. The ten-point average roughness is a value measured in accordance with JIS B0601:1994 using a laser microscope VK-9710 manufactured by Keyence under the measurement conditions of a 50-fold objective lens and no cutoff.

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 known lubricants can be used. Lubricants may be used singly or in combination of two or more. The amount of the lubricant present on the surface of the heat-sealable resin layer 5 is not particularly limited, and from the viewpoint of improving the moldability of the electronic packaging material, it is preferably 10 to 50 mg in an environment of a temperature of 24° C. and a humidity of 60%. /m ² , more preferably 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 obtained by exuding the lubricant contained in the resin constituting the heat-fusible resin layer 5, or the heat-fusible resin layer The surface of 5 may be coated with a lubricant.

The thickness of the heat-fusible resin layer 5 of the present invention is not particularly limited as long as it functions as a heat-fusible resin layer. 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, electrolyte resistance, scratch resistance, moldability, etc., on the substrate layer 1 (barrier layer of the substrate layer 1) 3), a surface coating layer 6 may be provided, if necessary. The surface coating layer 6 is the outermost layer when the battery is assembled.

The surface coating layer 6 can be made of, for example, polyvinylidene chloride, polyester resin, urethane resin, acrylic resin, epoxy resin, or the like. Among these, the surface coating layer 6 is preferably formed of a two-liquid curing resin. Examples of the two-liquid curable resin forming the surface coating layer 6 include a two-liquid curable urethane resin, a two-liquid curable polyester resin, and a two-liquid curable epoxy resin. Further, the surface coating layer 6 may contain additives. The additive added may function, for example, as a matting agent, and the surface coating layer may function as a matte 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, organic substances, and the like. The shape of the additive is also not particularly limited, but examples thereof include spherical, fibrous, plate-like, amorphous, and balloon-like shapes. Specific examples of 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 point nylon, crosslinked acrylic, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper, nickel, and the like. These additives may be used singly or in combination of two or more. Among these additives, silica, barium sulfate, and titanium oxide are preferred from the viewpoint of dispersion stability, cost, and the like. In addition, the additive may be subjected to various surface treatments such as insulation treatment and high-dispersion treatment.

A method for forming the surface coating layer 6 is not particularly limited, but for example, a method of coating one surface of the substrate layer 1 with a two-liquid curing resin that forms the surface coating layer 6 can be used. When an additive is blended, the additive may be added to the two-liquid curing 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 a surface coating layer.

3. Method for producing battery packaging material The method for producing the battery packaging material of the present invention is not particularly limited as long as a laminate obtained by laminating each layer having a predetermined composition is obtained. , a cured resin layer, and a heat-fusible resin layer in this order to obtain a laminated body, and in thermomechanical analysis for measuring the amount of displacement of the probe, the curing of the cross section of the laminated body The probe is placed on the surface of the resin layer, and the deflection setting value of the probe at the start of measurement is -4 V, and the temperature increase rate is 5 ° C./min. , a method of using a cured resin layer in which the position of the probe does not fall below the initial value can be adopted. That is, the battery packaging material of the present invention can be produced by laminating each layer using the cured resin layer 4 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 (hereinafter also referred to as "laminate A") is formed, which includes a substrate layer 1, an adhesive layer 2, and a barrier layer 3 in this order. Specifically, the laminate A is formed by applying an adhesive used for forming the adhesive layer 2 to the base material layer 1 or the barrier layer 3 whose surface is chemically treated as necessary, by extrusion or gravure coating. After coating and drying by a coating method such as a roll coating method, the barrier layer 3 or the base material layer 1 is laminated and the adhesive layer 2 is cured by a dry lamination method.

Next, on the barrier layer 3 of the laminate A, the cured resin layer 4 and the heat-fusible resin layer 5 are laminated. 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 are formed on the barrier layer 3 of the laminate A. 5 (co-extrusion lamination method); (3) applying the 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; (4) The barrier layer 3 of the laminate A and the heat A method of laminating the laminate A and the heat-fusible resin layer 5 via the cured resin layer 4 while pouring the melted hardened resin layer 4 between the heat-fusible resin layer 5 (sandwich lamination method), etc. is mentioned. Among these methods, method (3) is preferred. When the method (3) is employed, it is preferable to laminate the resin composition for forming the cured resin layer 4 on the barrier layer 3 and then dry it at a temperature of about 60 to 120°C. When the heat-fusible resin layer 5 is composed of a plurality of layers, the innermost layer of the heat-fusible resin layer 5 is preferably a layer formed by dry lamination or extrusion molding.

When providing the surface coating layer 6 , the surface coating layer 6 is laminated on the surface of the substrate layer 1 opposite to the barrier layer 3 . The surface coating layer 6 can be formed, for example, by coating the surface of the substrate layer 1 with the above-described resin for forming the surface coating layer 6 . 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 is not particularly limited. For example, after forming the surface coating layer 6 on the surface of the substrate layer 1 , the barrier layer 3 may be formed on the surface of the substrate layer 1 opposite to the surface coating layer 6 .

The method of adding the lubricant to the surface of the substrate layer 1 or the heat-fusible resin layer 5 is not particularly limited. However, if necessary, a method of exuding a lubricant to the surface, a method of applying a lubricant to the surface of the substrate layer 1 or the heat-fusible resin layer 5, and the like can be used.

As described above, the surface coating layer 6 provided as necessary, the base layer 1, the adhesive layer 2 provided as necessary, the barrier layer 3 whose surface is chemically treated as necessary, and the cured resin layer 4. A laminate having a heat-fusible resin layer 5 in this order is formed. It may be subjected to heat treatment such as roll contact type, hot air type, near-infrared type or far-infrared type. Conditions for such heat treatment include, for example, about 150 to 250° C. for about 1 to 5 minutes.

In the battery packaging material of the present invention, each layer constituting the laminate improves or stabilizes film formability, lamination processing, final product secondary processing (pouching, embossing) aptitude, etc. as necessary. For this purpose, surface activation treatment such as corona treatment, blasting treatment, oxidation treatment, and ozone treatment may be applied.

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

Specifically, a battery element comprising at least a positive electrode, a negative electrode, and an electrolyte is wrapped in the battery packaging material of the present invention in a state in which metal terminals connected to the positive electrode and the negative electrode protrude outward. The peripheral edge of the element is coated so as to form a flange portion (area where the heat-fusible resin layers contact each other), and the heat-fusible resin layers of the flange portion are heat-sealed to seal the battery. A battery using the packaging material for a battery is provided. When the battery packaging material of the present invention is used to accommodate a battery element, the heat-fusible resin portion of the battery packaging material of the present invention is placed inside (the surface in contact with the battery element).

The battery packaging material of the present invention may be used for either primary batteries or secondary batteries, preferably for secondary batteries. The type of secondary battery to which the battery packaging material of the present invention is applied is not particularly limited. , nickel/iron storage batteries, nickel/zinc storage batteries, silver oxide/zinc storage batteries, metal-air batteries, polyvalent cation batteries, capacitors, capacitors, and the like. Among these secondary batteries, lithium-ion batteries and lithium-ion polymer batteries can be cited as suitable targets for application of the battery packaging material of the present invention.

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples. However, the invention is not limited to the examples.

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

<Examples 1 to 5 and Comparative Examples 1 to 3>
A barrier layer made of an aluminum foil (thickness: 35 μm) having both sides subjected to chemical conversion treatment was laminated by a dry lamination method on a nylon film (thickness: 25 μm) as a base layer. Specifically, a two-component urethane adhesive (a polyol compound and an aromatic isocyanate compound) was applied to one surface of the aluminum foil to form an adhesive layer (3 μm thick) on the barrier layer. Next, after laminating the adhesive layer on the barrier layer and the substrate layer, aging treatment was performed at 40° C. for 24 hours to prepare a laminate of the substrate layer, the adhesive layer and the barrier layer. In addition, the chemical conversion treatment of the aluminum foil used as the barrier layer was carried out by roll-coating a treatment solution consisting of phenolic resin, chromium fluoride compound, and phosphoric acid so that the coating amount of chromium was 10 mg/m ² (dry mass). It was applied to both sides of an aluminum foil according to 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 films formed on both sides of the aluminum foil was 5 nm.

Next, a resin composition containing a main agent and a curing agent shown in Table 1 was applied to the other surface of the barrier layer of the obtained laminate so as to have a coating amount (dry weight) shown in Table 1. , and dried at 80° C. for 60 seconds to form a cured resin layer. Next, a polypropylene film (thickness: 35 μm) was laminated on the cured resin layer by a dry lamination method to form a heat-fusible resin layer. Through the steps described above, a laminate having a substrate layer, an adhesive layer, a barrier layer, a cured resin layer, and a heat-fusible resin layer in this order was obtained. From the viewpoint of enhancing the formability of the battery packaging material, erucamide was present as a lubricant on the surface of the innermost layer side (the side opposite to the barrier layer) of the unstretched polypropylene film. Next, each obtained laminate was aged in an environment of 70° C. for 24 hours to obtain battery packaging materials of Examples 1 to 6 and Comparative Examples 1 to 4. 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 a stainless steel foil (austenitic stainless steel foil, thickness 20 μm) was used as the barrier layer instead of the aluminum foil.

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

<Ten-Point Average Roughness of Surface of Heat-Sealable Resin Layer>
The surface of the heat-sealable resin layer of each battery packaging material obtained in Examples 1 to 6 was measured for ten-point average roughness by a method according to JIS B0601:1994. For the measurement, a laser microscope VK-9710 manufactured by Keyence was used, and the measurement was performed under the measurement conditions of a 50-fold objective lens and no cutoff. As a result, the ten-point average roughness was 1.1 μm for Examples 1, 2 and 4, and 1.2 μm for Examples 3, 5 and 6.

<Thermo-mechanical analysis for measuring 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 (the tip radius of the probe is 30 nm or less, the set value of the deflection of the probe is -4 V), and the probe is heated to 40 ° C. to 250° C. (heating rate of 5° C./min), and the amount of displacement of the probe was measured. Table 1 shows the results. Graphs showing the relationship between the heating temperature and the displacement of the probe position are 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 device, and a cantilever ThermaLever AN2-200 (spring constant 0.5 to 3 N/m) was used as a probe. For calibration, three 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 to 10V. , a speed of 0.2 V/sec, and a deflection setting of -4V. The positional displacement (Deflection(V)) represents the position (warp) of the probe tip, and the larger the value, the higher the probe tip (the probe is warped upward). For measuring the amount of displacement of the probe, cross sections along the TD and thickness directions were prepared for the battery packaging material, measurements were taken at five points on the cross section (see FIG. 10), and the average value was adopted. Also, calibration was performed 5 times and the average value was adopted.

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

<Durability evaluation>
Each of the battery packaging materials obtained above was cut into pieces of 60 mm (MD (machine direction)) x 150 mm (TD (transverse direction)) as shown in the schematic diagram of FIG. 6 (FIG. 6(a)). . Next, the cut battery packaging material was folded in two on the TD so that the heat-fusible resin layers faced each other (FIG. 6(b)). Next, one side E of the TD and one side F of the MD were heat-sealed (the width of the heat-sealed portion S was 7 mm) to prepare a bag-shaped battery packaging material in which one side of the TD was open. (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/pressurizing time of 3 seconds. Next, as shown in FIG. 6(d), 3 g of electrolytic solution H was injected from the opening G. Then, as shown in FIG. Next, the opening G was heat-sealed with a width of 7 mm under the same conditions as above (FIG. 6(e)). Electrolytic solution H was obtained by mixing lithium hexafluorophosphate into a solution in which ethylene carbonate:diethyl carbonate:dimethyl carbonate was mixed at a volume ratio of 1:1:1. Next, the part where the opening G of the battery packaging material had been positioned was turned upward (the state of FIG. 6(e)), and left still in a constant temperature layer at 85° C. for 24 hours. Regarding the MD and TD of the battery packaging material, for example, the rolling direction of the aluminum foil forming the barrier layer is the MD, and the direction perpendicular to the MD is the TD. The rolling direction of the aluminum foil can be confirmed by the rolling marks of the aluminum foil.

Next, each battery packaging material is taken out from the constant temperature layer, and as shown in FIG. The packaging material was opened and the electrolytic solution H was taken out (Fig. 6(g)). Next, a portion with a width W of 15 mm in TD of the battery packaging material was cut into strips (a two-dot chain line in FIG. 6(h)) to obtain a test piece T (FIG. 6(I)). The heat-fusible resin layer and the barrier layer of the obtained test piece T were separated, and the heat-fusible resin layer and the barrier layer were separated by 50 mm using a tensile tester (trade name: AGS-XPlus manufactured by Shimadzu Corporation). /min, and the peel strength (N/15 mm) of the test piece was measured (peel strength after durability test). On the other hand, the 180 degree peel strength was measured in the same manner for test pieces T obtained by cutting the battery packaging materials obtained in Examples 1 to 6 and Comparative Examples 1 to 4 to a width of MD 15 mm × TD 40 mm. peel strength). Table 1 shows the results. In addition, the measured value is an average value of N=3. Moreover, the measurement of the peel strength of the test piece was carried out in an environment of a temperature of 25° C. and a relative humidity of 50%. When the heat-fusible resin layer and the barrier layer are separated, the cured resin layer positioned between these layers is laminated on either one or both of the heat-fusible resin layer and the barrier layer. Become.

<Evaluation of insulating properties against foreign matter entrapment>
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. 7(a)). Next, this test piece was folded so that the short sides thereof faced each other, and the surfaces of the heat-fusible resin layers of the test piece were arranged so as to face 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. 7(b)). Next, in this state, the heat-sealing resin layers are heat-sealed (at a temperature of 190° C., surface The pressure was 1.0 MPa, the heating and pressurizing time was 3 seconds) (Fig. 7(c), heat-sealed portion S). At this time, heat sealing was performed from above the portion where the wire M was positioned, and the heat-sealable resin layer was heat-sealed to the wire M. Next, the positive pole of the tester was connected to the wire M, and the negative pole to the battery packaging material on one side. At this time, for the negative electrode of the tester, an alligator clip was inserted so as to reach the aluminum layer from the base layer side of the electrical packaging material, and the negative electrode 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. Table 1 shows the results.

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

As shown in Table 1, in the battery packaging materials obtained in Examples 1 to 6, in 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 measurement When the probe was heated from 40° C. to 220° C. under conditions of −4 V and a heating rate of 5° C./min, the position of the probe did not fall below the initial value. On the other hand, in the battery packaging materials obtained in Comparative Examples 1 to 4, when the probe was heated from 40 ° C. to 220 ° C. in thermomechanical analysis for measuring the amount of displacement of the probe, the position of the probe was higher than the initial value. was declining.

*1: The position of the probe is lower at temperatures below 120°C than at 80°C.
*2: The position of the probe is lower at temperatures below 220°C than at 140°C.

REFERENCE SIGNS LIST 1 Base layer 2 Adhesive layer 3 Barrier layer 4 Cured resin layer 4a Probe installation position 5 Heat-fusible resin layer 10 Probe

Claims (15)

At least, it is composed of a laminate including a base material layer, a barrier layer, a cured resin layer, and a heat-fusible resin layer in this order,
The cured resin layer is a cured product of a resin composition containing an acid-modified polyolefin,
In the thermomechanical analysis for measuring the amount of displacement of the probe, the probe is installed 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 measurement is -4 V and the temperature rise rate is 5. A packaging material for a battery, wherein the position of the probe does not decrease below the initial value when the probe is heated from 40°C to 220°C under the condition of °C/min. 2. The battery packaging material according to claim 1, wherein the resin constituting said cured resin layer contains a polyolefin skeleton. At least, it is composed of a laminate including a base material layer, a barrier layer, a cured resin layer, and a heat-fusible resin layer in this order,
The resin constituting the cured resin layer contains a polyolefin skeleton,
In the thermomechanical analysis for measuring the amount of displacement of the probe, the probe is installed 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 measurement is -4 V and the temperature rise rate is 5. A packaging material for a battery, wherein the position of the probe does not decrease below the initial value when the probe is heated from 40°C to 220°C under the condition of °C/min. 4. The battery packaging material according to claim 3, wherein the cured resin layer is a cured 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 1, 2, or 4, wherein the heat-fusible resin layer contains polypropylene. In the thermomechanical analysis for measuring the amount of displacement of the probe, the probe is installed 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 measurement is -4 V and the temperature rise rate is 5. When the probe is heated from 40 ° C. to 220 ° C. under the conditions of ° C./min, the amount of rise in the position of the probe when heated from 140 ° C. to 220 ° C. is the same as that when heated from 80 ° C. to 120 ° C. 6. The battery packaging material according to any one of claims 1 to 5 , wherein the amount of elevation of the position of the probe is larger than that of the probe. Claims 1 to 6 , wherein 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 oxygen atoms, heterocycles, C═N bonds, and C—O—C bonds. Item 8. The battery packaging material according to any one of items 1 to 7 . The battery packaging material according to any one of claims 1 to 8 , 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 9 , wherein the cured resin layer has a thickness of 0.6 µm or more and 11 µm or less. The battery packaging material according to any one of claims 1 to 10 , wherein the softening temperature of said cured resin layer is in the range of 180°C or higher and 260°C or lower. The battery packaging material according to any one of claims 1 to 11 , wherein the heat-fusible resin layer has a thickness in the range of 10 µm or more and 40 µm or less. The battery packaging material according to any one of claims 1 to 12 , wherein the heat-fusible resin layer has fine irregularities on its surface. A lamination step of obtaining a laminate comprising at least a substrate layer, a barrier layer, a cured resin layer, and a heat-fusible resin layer in this order,
The cured resin layer is a cured product of a resin composition containing an acid-modified polyolefin,
In thermomechanical analysis for measuring the amount of displacement of the probe, the probe is installed on the surface of the cured resin layer at the end of the laminate, and the set value of the deflection of the probe at the start of measurement is -4 V, the temperature increase rate A method for producing a battery packaging material, wherein the cured resin layer does not lower the position of the probe than the initial value when the probe is heated from 40° C. to 220° C. under the condition of 5° C./min. A lamination step of obtaining a laminate comprising at least a substrate layer, a barrier layer, a cured resin layer, and a heat-fusible resin layer in this order,
The resin constituting the cured resin layer contains a polyolefin skeleton,
In thermomechanical analysis for measuring the amount of displacement of the probe, the probe is installed on the surface of the cured resin layer at the end of the laminate, and the set value of the deflection of the probe at the start of measurement is -4 V, the temperature increase rate A method for producing a battery packaging material, wherein the cured resin layer does not lower the position of the probe than the initial value when the probe is heated from 40° C. to 220° C. under the condition of 5° C./min.

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