WO2016159233A1

WO2016159233A1 - Packaging material for cell, process for producing same, and cell

Info

Publication number: WO2016159233A1
Application number: PCT/JP2016/060654
Authority: WO
Inventors: 一彦横田
Original assignee: 大日本印刷株式会社
Priority date: 2015-03-31
Filing date: 2016-03-31
Publication date: 2016-10-06
Also published as: JP6939545B2; JPWO2016159233A1

Abstract

Provided is a packing material for cells which has high insulating properties. The packing material for cells is constituted of a laminate which comprises, in the following order along the thickness direction, an outer layer, an interlayer constituted of a metal foil, and an inner layer constituted of a fusion-bondable resin, wherein the inner layer comprises a resin layer that is constituted of a resin having a melt viscosity, as measured in a dry nitrogen atmosphere at 170ºC and a rotation speed of 20 rpm, of 150-900 Pa·sec and that has a thickness of 20 µm or greater.

Description

Battery packaging material, manufacturing method thereof, and battery

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

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

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

Therefore, as a battery packaging material that can be easily processed into various shapes and can be made thinner and lighter, it is a film in which an intermediate layer / a heat-fusible resin layer composed of an outer layer / metal foil is sequentially laminated. The laminated body of this is proposed. In such a battery packaging material, generally, a recess is formed by molding, and a battery element such as an electrode or an electrolytic solution is accommodated in the space formed by the recess, and the heat-fusible resin layers are heated together. By welding, a battery in which the battery element is accommodated in the battery packaging material is obtained.

For example, Patent Document 1 discloses a battery case including a biaxially stretched polyamide film layer as an outer layer, an unstretched thermoplastic resin film layer as an inner layer, and an aluminum foil layer disposed between the two film layers. A packaging material is disclosed.

JP 2008-287971 A

As a result of intensive studies by the inventor, the battery packaging material disclosed in Patent Document 1 has a problem that the insulation may be lowered when the battery packaging material is applied to a battery. It was done.

Therefore, as a result of further earnest studies by the present inventors, when the electrolytic solution is accommodated in the battery packaging material in the battery manufacturing process, the electrolytic solution is attached to the thermally welded portion of the inner layer, It has been found that the inner layer may be thermally welded. In such a case, bubbles formed by evaporation of the electrolyte located in the heat-welded portion are formed in the melted inner layer by heating at the time of heat-welding (for example, a high temperature of 170 ° C. or higher). In addition, it has been clarified that the bubbles grow larger and reach the intermediate layer composed of the metal foil or the vicinity thereof, and the thickness of the inner layer of the heat welded portion is reduced. This is because cutting the heat-welded part of the battery packaging material with low insulation and observing the cross section using a microtome, the part of the inner layer was greatly deformed due to the growth of bubbles was confirmed It was revealed from When the thickness of the heat-welded portion of the heat-fusible resin layer is reduced, there is a problem that the metal tab and the intermediate layer composed of the metal foil are easily brought into contact with or close to each other, resulting in a decrease in battery insulation.

The present invention is an invention made by finding such a new problem. That is, the main object of the present invention is to provide a battery packaging material having high insulation properties.

The present inventor has intensively studied to solve the above problems. As a result, in the thickness direction, it is composed of a laminate comprising an outer layer, an intermediate layer composed of a metal foil, and an inner layer composed of a heat-fusible resin, and the inner layer is rotated at 170 ° C. under dry nitrogen. By providing a resin layer having a thickness of 20 μm or more, which is composed of a resin having a melt viscosity of 150 Pa · sec or more and 900 Pa · sec or less at a speed of 20 rpm, the battery packaging material exhibits high insulation. I found it. The present invention has been completed by further studies based on these findings.

That is, this invention provides the packaging material for batteries of the aspect hung up below, its manufacturing method, and a battery.
Item 1. In the thickness direction, in order, a laminate comprising an outer layer, an intermediate layer composed of a metal foil, and an inner layer composed of a heat-fusible resin,
The inner layer includes a resin layer having a thickness of 20 μm or more, which is made of a resin having a melt viscosity of 150 Pa · sec or more and 900 Pa · sec or less at 170 ° C. and a rotation speed of 20 rpm under dry nitrogen. material.
Item 2. The inner layer is composed of one layer of the first heat-fusible resin layer,
The first heat-fusible resin layer is made of polypropylene,
The first heat-fusible resin layer is the resin layer;
Item 4. A battery packaging material according to Item 1.
Item 3. The inner layer is composed of two layers: a first heat-fusible resin layer as an outermost layer opposite to the intermediate layer, and a second heat-fusible resin layer adjacent to the first heat-fusible resin layer. Configured,
The first heat-fusible resin layer is made of polypropylene,
The second heat-fusible resin layer is the resin layer;
Item 4. A battery packaging material according to Item 1.
Item 4. The inner layer includes a first heat-fusible resin layer as an outermost layer opposite to the intermediate layer, a second heat-fusible resin layer adjacent to the first heat-fusible resin layer, and the first layer 2 is composed of three layers of a heat-fusible resin layer and a third heat-fusible resin layer adjacent thereto,
The first heat-fusible resin layer is made of polypropylene,
At least one of the second heat-fusible resin layer and the third heat-fusible resin layer is the resin layer;
Item 4. A battery packaging material according to Item 1.
Item 5. Item 5. The battery packaging according to

Item

3 or 4, wherein the first heat-fusible resin layer is made of polypropylene having a melt viscosity of 120 Pa · sec or less at 170 ° C. and a rotation speed of 20 rpm under dry nitrogen. material.
Item 6. Item 6. The battery packaging material according to any one of Items 1 to 5, wherein the total thickness of the inner layer is 50 μm or less.
Item 7. Item 7. The battery packaging material according to any one of Items 1 to 6, further comprising an adhesive layer between the intermediate layer and the inner layer.
Item 8. A battery in which a battery element including a positive electrode, a negative electrode, and an electrolyte is sealed with a package formed of the battery packaging material according to any one of Items 1 to 7.
Item 9. In order in the thickness direction, comprising a step of obtaining a laminate comprising an outer layer, an intermediate layer composed of a metal foil, and an inner layer composed of a heat-fusible resin,
Production of a packaging material for a battery, in which a resin layer having a melt viscosity of 150 Pa · sec or more and 900 Pa · sec or less and having a thickness of 20 μm or more is provided as the inner layer under dry nitrogen at 170 ° C. and a rotation speed of 20 rpm. Method.

According to the present invention, in the battery packaging material comprising a laminate including an outer layer, an intermediate layer composed of a metal foil, and an inner layer composed of a heat-fusible resin in the thickness direction, the inner layer is dried. A battery having a high insulating property by including a resin layer having a thickness of 20 μm or more, which is made of a resin having a melt viscosity of 150 Pa · sec or more and 900 Pa · sec or less at 170 ° C. and a rotation speed of 20 rpm under nitrogen. Packaging materials can be provided. That is, the battery insulation can be enhanced by sealing the battery element with the battery packaging material of the present invention.

It is a schematic sectional drawing of an example of the packaging material for batteries which concerns on this invention. It is a schematic sectional drawing of an example of the packaging material for batteries which concerns on this invention. It is a schematic sectional drawing of an example of the packaging material for batteries which concerns on this invention. It is a schematic sectional drawing of an example of the packaging material for batteries which concerns on this invention. It is a schematic sectional drawing of an example of the packaging material for batteries which concerns on this invention.

The battery packaging material of the present invention comprises a laminate comprising, in the thickness direction, an outer layer, an intermediate layer composed of a metal foil, and an inner layer composed of a heat-fusible resin. The resin layer is made of a resin having a melt viscosity of 150 Pa · sec or more and 900 Pa · sec or less at 170 ° C. and a rotation speed of 20 rpm, and having a thickness of 20 μm or more. Hereinafter, the battery packaging material of the present invention, the production method thereof, and the battery of the present invention in which the battery element is sealed with the battery packaging material of the present invention will be described in detail with reference to FIGS.

1. As shown in FIGS. 1 and 2, the battery packaging material has, in the thickness direction, an outer layer, an intermediate layer composed of a metal foil, and an inner layer composed of a heat-fusible resin. And an outer layer intermediate layer laminate. In the battery packaging material of the present invention, the outer layer is the outermost layer side, and the inner layer is the innermost layer. That is, when the battery is assembled, the inner layers 4 positioned on the periphery of the battery element are thermally welded to seal the battery element, thereby sealing the battery element.

1 and 2, the inner layer 4 is composed of one layer of the first heat-fusible resin layer 41. In this configuration, the first heat-fusible resin layer 41 is made of polypropylene, and the first heat-fusible resin layer 41 is the aforementioned resin layer.

In FIG. 3, the inner layer 4 includes a first heat-fusible resin layer 41 as the outermost layer opposite to the intermediate layer 3, and a second heat-fusible resin adjacent to the first heat-fusible resin layer 41. The layer 42 is composed of two layers. In this configuration, the first heat-fusible resin layer 41 is made of polypropylene, and the second heat-fusible resin layer 42 is the aforementioned resin layer.

4 and 5, the inner layer 4 includes a first heat-fusible resin layer 41 as an outermost layer opposite to the intermediate layer 3, and a second heat-fusible resin layer 41 adjacent to the first heat-fusible resin layer 41. The adhesive layer is composed of three layers, that is, an adhesive resin layer 42 and a third thermal adhesive resin layer 43 adjacent to the second thermal adhesive resin layer 42. In this configuration, the first heat-fusible resin layer 41 is made of polypropylene, and at least one of the second heat-fusible resin layer 42 and the third heat-fusible resin layer 43 is the aforementioned resin. Is a layer.

The inner layer 4 may be composed of four or more layers. In the present invention, the melt viscosity is a value measured using MiniLab manufactured by HAAKE.

As shown in FIG. 2, the battery packaging material of the present invention is provided with an adhesive layer 2 between the outer layer 1 and the intermediate layer 3 for the purpose of enhancing the adhesiveness as required. Good. Further, as shown in FIG. 5, the battery packaging material of the present invention is provided with an adhesive layer 5 between the intermediate layer 3 and the inner layer 4 as necessary for the purpose of enhancing the adhesiveness thereof. Also good.

The total thickness of the laminate constituting the battery packaging material of the present invention is not particularly limited, but from the viewpoint of exhibiting high insulation while reducing the thickness of the battery packaging material, preferably about 50 μm or more and 150 μm or less, More preferably, it is about 55 μm or more and 120 μm or less.

[Outer layer 1]
In the battery packaging material of the present invention, the outer layer 1 is a layer positioned as the outermost layer when the battery is assembled when a surface coating layer to be described later is not provided. The material forming the outer layer 1 is not particularly limited as long as it has insulating properties. Examples of the material forming the outer layer 1 include resin films such as polyester resin, polyamide resin, epoxy resin, acrylic resin, fluorine resin, polyurethane resin, silicon resin, phenol resin, and mixtures and copolymers thereof. . Among these, Preferably a polyester resin and a polyamide resin are mentioned, More preferably, a biaxially stretched polyester resin and a biaxially stretched polyamide resin are mentioned. Specific examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolyester, and polycarbonate. Specific examples of the polyamide resin include nylon 6, nylon 6,6, a copolymer of nylon 6 and nylon 6,6, nylon 6,10, polymetaxylylene adipamide (MXD6), and the like. It is done.

The outer layer 1 may be formed from a single-layer resin film, but may be formed from two or more resin films in order to improve pinhole resistance and insulation. For example, when the outer layer 1 is formed from a two-layer resin film, the polyester resin / polyamide resin structure is preferable, and the polyethylene terephthalate / nylon structure is more preferable. In addition, in the said laminated structure, it is preferable to laminate | stack the outer layer 1 so that a polyester resin or a polyethylene terephthalate may be located in an outermost layer.

When the outer 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. For the type and amount of the adhesive component used, etc. This is the same as the case of the adhesive layer 2 described later. In addition, it does not restrict | limit especially as a method of laminating | stacking two or more resin films, A well-known method can be employ | adopted, for example, a dry lamination method, a sandwich lamination method, etc. are mentioned, Preferably the dry lamination method is mentioned. When laminating by the dry laminating method, it is preferable to use a urethane-based adhesive as the adhesive layer. At this time, as a thickness of an adhesive bond layer, 2 micrometers or more and about 5 micrometers or less are mentioned, for example.

The thickness of the outer layer 1 is not particularly limited as long as the battery packaging material satisfies the above physical properties while exhibiting the function as the outer layer. For example, the thickness is about 10 μm to 50 μm, preferably about 10 μm to 35 μm. .

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

The adhesive layer 2 is formed of an adhesive that can bond the outer layer 1 and the intermediate layer 3 together. The adhesive used for forming the adhesive layer 2 may be a two-component curable adhesive or a one-component curable adhesive. Furthermore, the bonding mechanism of the adhesive used for forming the adhesive layer 2 is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a heat melting type, a hot pressure type, and the like.

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

The thickness of the adhesive layer 2 is not particularly limited as long as the battery packaging material satisfies the above physical properties while exhibiting the function as the adhesive layer. For example, the thickness is about 1 μm to 10 μm, preferably 2 μm to 5 μm. Degree.

[Intermediate layer 3]
In the battery packaging material, the intermediate layer 3 is made of a metal foil. The intermediate layer 3 is a layer that functions as a barrier layer for preventing water vapor, oxygen, light, and the like from entering the battery, in addition to improving the strength of the battery packaging material. Specific examples of the metal constituting the intermediate layer 3 include aluminum, stainless steel, and titanium, and preferably aluminum. The intermediate layer 3 is more preferably composed of an aluminum foil. From the viewpoint of preventing generation of wrinkles and pinholes in the intermediate layer 3 during the production of the battery packaging material, for example, annealed aluminum (JIS H4160 A8021H-O, JIS H4160 A8079H-O, JIS H4000: It is more preferable to use a soft aluminum foil such as 2014 A8021P-O, JIS H4000: 2014 A8079P-O).

The thickness of the intermediate layer 3 is not particularly limited as long as it functions as a barrier layer such as water vapor, but can be, for example, about 10 μm to 50 μm, preferably about 10 μm to 35 μm.

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

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

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

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

The amount of acid-resistant coatings to be formed on the surface of the intermediate layer 3 in the chemical conversion treatment is not particularly limited, for example, in the case of performing the above-mentioned chromate treatment, the surface 1 m ² per intermediate layer 3, chromic acid compounds About 0.5 mg to about 50 mg in terms of chromium, preferably about 1.0 mg to about 40 mg, phosphorus compound in terms of phosphorus, about 0.5 mg to about 50 mg, preferably about 1.0 mg to about 40 mg, and It is desirable that the aminated phenol polymer is contained in an amount of about 1 mg to about 200 mg, preferably about 5.0 mg to 150 mg.

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

[Inner layer 4]
In the battery packaging material of the present invention, the inner layer 4 is made of a heat-fusible resin. The inner layer 4 corresponds to the innermost layer, and is a layer in which the inner layers are thermally welded when the battery is assembled to seal the battery element. In the present invention, the inner layer 4 includes a resin layer having a thickness of 20 μm or more, which is made of a resin having a melt viscosity of 150 Pa · sec or more and 900 Pa · sec or less at 170 ° C. and a rotation speed of 20 Pa under dry nitrogen. Yes.

As described above, as a result of extensive studies by the inventor, when the electrolytic solution is accommodated in the battery packaging material in the battery manufacturing process, the electrolytic solution is attached to the heat-welded portion of the inner layer. It has been found that the inner layer may be thermally welded. In such a case, when a conventional battery packaging material is used, the electrolyte solution located in the thermally welded portion is vaporized and formed by heating at the time of thermal welding (for example, a high temperature of 170 ° C. or higher). It is clear that the bubbles are formed in the melted inner layer, the bubbles grow large and reach the intermediate layer made of metal foil or the vicinity thereof, and the thickness of the inner layer of the heat welded portion is reduced. became. This is because cutting the heat-welded part of the battery packaging material with low insulation and observing the cross section using a microtome, the part of the inner layer was greatly deformed due to the growth of bubbles was confirmed It was revealed from When the thickness of the heat-welded portion of the inner layer is reduced, there is a problem that the insulating properties of the battery are lowered.

On the other hand, in the battery packaging material of the present invention, the inner layer 4 includes the resin layer having the specific melt viscosity and thickness, so that the electrolyte is attached to the heat-welded portion of the inner layer. Thus, even when the inner layer is thermally welded, it is possible to effectively suppress the bubbles of the electrolyte from growing greatly in the melted inner layer. That is, in the conventional battery packaging material, the resin having a melt viscosity much lower than 150 Pa · sec is used for the inner layer in consideration of heat weldability. In the present invention, the above melt viscosity is used. Is formed of a resin of 150 Pa · sec or more, and the inner layer 4 includes a resin layer having a thickness of 20 μm or more. For this reason, it can suppress effectively that the bubble of electrolyte solution grows in the inner layer 4 fuse | melted at the time of heat welding. Therefore, in the battery packaging material of the present invention, insulation is effectively enhanced.

The inner layer 4 is composed of a single layer or multiple layers.
As shown in FIGS. 1 and 2, the inner layer 4 is composed of one layer of the first heat-fusible resin layer 41, and the first heat-fusible resin layer 41 is composed of polypropylene. A mode in which the first heat-fusible resin layer 41 is the above-described resin layer is preferable.

As shown in FIG. 3, the inner layer 4 includes a first heat-fusible resin layer 41 as the outermost layer opposite to the intermediate layer 3, and a second heat-adhesive resin layer 41 adjacent to the first heat-fusible resin layer 41. The heat-fusible resin layer 42 is composed of two layers, the first heat-fusible resin layer 41 is composed of polypropylene, and the second heat-fusible resin layer 42 is the aforementioned resin layer. Some embodiments are preferred.

Further, as shown in FIGS. 4 and 5, the inner layer 4 is adjacent to the first heat-fusible resin layer 41 and the first heat-fusible resin layer 41 as the outermost layer opposite to the intermediate layer 3. The second heat-fusible resin layer 42 and the third heat-fusible resin layer 43 adjacent to the second heat-fusible resin layer 42, and the first heat-fusible resin layer 43. It is preferable that 41 is made of polypropylene, and at least one of the second heat-fusible resin layer 42 and the third heat-fusible resin layer 43 is the above-described resin layer.

The total thickness of the inner layer 4 is not particularly limited, but is preferably 50 μm or less, more preferably about 23 μm or more and 46 μm or less from the viewpoint of exhibiting high insulation while thinning the battery packaging material.

(Resin layer)
In the present invention, the melt viscosity of the resin layer contained in the inner layer 4 is 150 Pa · sec or more, 900 Pa · sec or less, more preferably 160 Pa · sec or more, at 170 ° C. and a rotation speed of 20 rpm under dry nitrogen. 870 Pa · sec or less. For example, when the resin layer is laminated by extrusion molding, the melt viscosity of the resin layer is preferably 150 Pa · sec or more and 500 Pa · sec or less, more preferably 180 Pa · sec or more and 450 Pa · sec. sec or less. On the other hand, when the resin layer is laminated on the intermediate layer 3 in the form of a laminated film, the melt viscosity of the resin layer is preferably 500 Pa · sec or more and 900 Pa · sec or less, more preferably Examples include 600 Pa · sec or more and 870 Pa · sec or less. The melt viscosity of the resin layer can be adjusted by the type of resin constituting the resin layer, the weight average molecular weight, the additive, and the like.

Although it does not restrict | limit especially as melting | fusing point of a resin layer, Preferably it is about 140 to 165 degreeC, More preferably, about 150 to 160 degreeC is mentioned. In the present invention, the melting point of the resin is a value measured by the DSC method in accordance with JIS K6921-2 (ISO 1873-2.2: 95).

The thickness of the resin layer may be 20 μm or more, preferably about 20 μm to 46 μm, more preferably about 20 μm to 30 μm.

In the present invention, at least one of the layers (for example, the first to third heat-fusible resin layers) included in the inner layer 4 constitutes a resin layer. In the inner layer 4, it is preferable that only one resin layer is provided.

(First heat-fusible resin layer 41)
In the present invention, the first heat-fusible resin layer 41 is located on the outermost layer on the side opposite to the intermediate layer 3 of the inner layer 4 and is a layer formed of polypropylene. When the inner layer 4 is composed of a single layer, the first heat-fusible resin layer 41 is the aforementioned resin layer. That is, in this case, the first heat-fusible resin layer 41 is formed of a resin having a melt viscosity of 150 Pa · sec or more and 900 Pa · sec or less under dry nitrogen at 170 ° C. and a rotation speed of 20 rpm. 20 μm or more.

On the other hand, when the inner layer 4 is formed of multiple layers, the first heat-fusible resin layer 41 is formed of polypropylene having a melt viscosity at 170 ° C. and a rotation speed of 20 rpm under dry nitrogen at 120 Pa · sec or less. It is preferable that In this case, the melt viscosity of polypropylene is preferably about 60 Pa · sec to 110 Pa · sec.

The melting point of the polypropylene constituting the first heat-fusible resin layer 41 is not particularly limited, but is preferably about 120 ° C to 160 ° C, more preferably about 135 ° C to 150 ° C.

The polypropylene constituting the first heat-fusible resin layer 41 is not particularly limited, and is a block copolymer of polypropylene (for example, a block copolymer of propylene and ethylene) or a random copolymer of polypropylene (for example, a random copolymer of propylene and ethylene). And a homopolymer of polypropylene. Among these, a random copolymer of polypropylene is preferable. Moreover, as a polypropylene, you may use individually by 1 type and may be used in combination of 2 or more types.

The thickness of the first heat-fusible resin layer 41 is not particularly limited. For example, when the inner layer 4 is composed of a single layer of the first heat-fusible resin layer 41, the thickness of the first heat-fusible resin layer 41 corresponds to the total thickness of the inner layer 4 described above. When the inner layer 4 is composed of multiple layers, the thickness of the first heat-fusible resin layer 41 is not particularly limited, but is preferably about 20 μm or more and 50 μm or less, more preferably about 23 μm or more and 46 μm or less. Can be mentioned.

(Second heat-fusible resin layer 42)
The second heat-fusible resin layer 42 is a first heat-fusible resin layer 41 as the outermost layer on the side opposite to the intermediate layer 3 when the heat-fusible resin layer 4 is composed of multiple layers. And adjacent layers. The melt viscosity of the second heat-fusible resin layer 42 is not particularly limited, but when the second heat-fusible resin layer 42 is a resin layer, it becomes the melt viscosity of the resin layer.

The melting point of the resin constituting the second heat-fusible resin layer 42 is not particularly limited, but is preferably about 140 ° C. or more and 165 ° C. or less, more preferably about 150 ° C. or more and 160 ° C. or less.

The resin component used for the second heat-fusible resin layer 42 is not particularly limited as long as it can be heat-welded. For example, polyolefin, cyclic polyolefin, carboxylic acid-modified polyolefin, Can be mentioned.

Specific examples of the polyolefin include polyethylene such as low density polyethylene, medium density polyethylene, high density polyethylene, and linear low density polyethylene; homopolypropylene, polypropylene block copolymer (for example, block copolymer of propylene and ethylene), polypropylene And a random copolymer (eg, a random copolymer of propylene and ethylene); an ethylene-butene-propylene terpolymer; and the like. Among these polyolefins, polyethylene and polypropylene are preferable.

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

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

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

The second heat-fusible resin layer 42 may be formed of one kind of resin component alone, or may be formed of a blend polymer in which two or more kinds of resin components are combined.

When the second heat-fusible resin layer 42 is adjacent to the intermediate layer 3, the second heat-fusible resin layer 42 is made of the above-described carboxylic acid-modified polyolefin. It is preferably formed from a carboxylic acid-modified cyclic polyolefin. Further, when the heat-fusible resin layer 4 further has another layer (for example, the third heat-fusible resin layer 43) constituting the inner layer 4 on the intermediate layer 3 side, the second heat-fusible resin layer 4 is provided. The conductive resin layer 42 is preferably formed of the aforementioned polyolefin, cyclic polyolefin, or the like.

The thickness of the second heat-fusible resin layer 42 is not particularly limited, but is preferably about 20 μm to 46 μm, and more preferably about 20 μm to 30 μm.

(Third heat-fusible resin layer 43)
The third heat-fusible resin layer 43 is a layer adjacent to the second heat-fusible resin layer when the heat-fusible resin layer 4 is composed of three or more layers. The melt viscosity of the third heat-fusible resin layer 43 is not particularly limited, but when the third heat-fusible resin layer 43 is a resin layer, it becomes the melt viscosity of the resin layer.

The melting point of the resin constituting the third heat-fusible resin layer 43 is not particularly limited, but is preferably about 120 ° C. to 160 ° C., more preferably about 135 ° C. to 150 ° C.

The resin component used for the third heat-fusible resin layer 43 is not particularly limited as long as it can be heat-welded, and is the same as that exemplified in the second heat-fusible resin layer 42 described above. Can be illustrated.

When the third heat-fusible resin layer 43 is adjacent to the intermediate layer 3, the third heat-fusible resin layer 43 has the above-described carboxylic acid modification since it has high adhesion to the intermediate layer 3. It is preferably formed from an acid-modified polyolefin such as polyolefin or carboxylic acid-modified cyclic polyolefin.

The thickness of the third heat-fusible resin layer 43 is not particularly limited, but is preferably about 3 μm to 15 μm, more preferably about 3 μm to 10 μm.

(Other layers of inner layer 4)
When the inner layer 4 is formed of four or more layers, in addition to the first to third heat-fusible resin layers, the inner layer 4 further includes a fourth heat-fusible resin layer, a fifth heat-fusible resin layer, and the like. Other layers may be included. The configuration of the other layers can be the same as that of the third heat-fusible resin layer.

[Adhesive layer 5]
In the battery packaging material of the present invention, an adhesive layer 5 is further provided between the intermediate layer 3 and the inner layer 4 as necessary for the purpose of firmly bonding the intermediate layer 3 and the inner layer 4. Also good.

The adhesive layer 5 is formed of an adhesive component capable of bonding the intermediate layer 3 and the inner layer 4. The adhesive used for forming the adhesive layer 5 may be a two-component curable adhesive or a one-component curable adhesive. Moreover, it does not specifically limit about the adhesion | attachment mechanism of the adhesive agent component used for formation of the contact bonding layer 5, For example, a chemical reaction type | mold, a solvent volatilization type | mold, a hot-melt type, a hot-pressure type etc. are mentioned.

Specific examples of the adhesive component that can be used to form the adhesive layer 5 include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, copolymer polyester, and other polyester resins; polyethers Polyurethane adhesives; epoxy resins; phenol resin resins; polyamide resins such as nylon 6, nylon 66, nylon 12, copolymer polyamides; polyolefins such as polyolefins, carboxylic acid modified polyolefins, metal modified polyolefins Resin, polyvinyl acetate resin; cellulose adhesive; (meth) acrylic resin; polyimide resin; urea resin, melamine resin and other amino resins; chloroprene rubber, nitrile rubber - styrene rubbers such as butadiene rubber; and silicone resins. These adhesive components may be used alone or in combination of two or more.

When the inner layer 4 is laminated on the intermediate layer 3 in the form of a laminated film, it is preferable to bond the intermediate layer 3 and the inner layer 4 via the adhesive layer 5. For example, when the inner layer 4 is formed of three or more layers, the inner layer 4 is preferably laminated on the intermediate layer 3 as a laminated film of three or more layers. For this reason, it can be said that it is preferable to have the adhesive layer 5 when the inner layer 4 is composed of three or more layers.

The thickness of the adhesive layer 5 is not particularly limited, but is preferably about 1 μm to 10 μm, and more preferably about 2 μm to 5 μm.

[Surface coating layer]
In the battery packaging material of the present invention, the outer layer 1 (as opposed to the intermediate layer 3 of the outer layer 1) may be used as necessary for the purpose of improving design properties, electrolytic solution resistance, scratch resistance, moldability, and the like. On the side), a surface coating layer (not shown) may be provided if necessary. A surface coating layer is a layer located in the outermost layer when a battery is assembled.

The surface coating layer can be formed of, for example, polyvinylidene chloride, polyester resin, urethane resin, acrylic resin, epoxy resin, or the like. Of these, the surface coating layer is preferably formed of a two-component curable resin. Examples of the two-component curable resin that forms the surface coating layer include a two-component curable urethane resin, a two-component curable polyester resin, and a two-component curable epoxy resin. Moreover, you may mix | blend a matting agent with a surface coating layer.

Examples of the matting agent include fine particles having a particle size of about 0.5 nm to 5 μm. The material of the matting agent is not particularly limited, and examples thereof include metals, metal oxides, inorganic substances, and organic substances. The shape of the matting agent is not particularly limited, and examples thereof include a spherical shape, a fiber shape, a plate shape, an indeterminate shape, and a balloon shape. Specific examples of the matting agent include talc, silica, graphite, kaolin, montmorilloid, montmorillonite, synthetic mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, and 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 can be mentioned. These matting agents may be used individually by 1 type, and may be used in combination of 2 or more type. Among these matting agents, silica, barium sulfate, and titanium oxide are preferable from the viewpoint of dispersion stability and cost. The matting agent may be subjected to various surface treatments such as insulation treatment and high dispersibility treatment on the surface.

The method for forming the surface coating layer is not particularly limited, and examples thereof include a method of applying a two-component curable resin for forming the surface coating layer on one surface of the outer layer 1. When the matting agent is blended, the matting agent may be added to the two-component curable resin, mixed, and then applied.

The thickness of the surface coating layer is not particularly limited as long as the battery packaging material satisfies the above physical properties while exhibiting the above function as the surface coating layer. For example, the thickness is about 0.5 μm to 10 μm, preferably 1 μm. For example, about 5 μm or less.

3. Production method of battery packaging material The production method of the battery packaging material of the present invention is not particularly limited as long as a laminate in which layers of a predetermined composition are laminated is obtained. At least the outer layer 1 and the intermediate layer 3 And a single-layer or multiple-layer inner layer 4 are laminated in this order to obtain a laminated body. As the inner layer 4, a manufacturing method using the following can be adopted.
In order in the thickness direction, comprising a step of obtaining a laminate outer layer intermediate layer comprising an outer layer, an intermediate layer composed of a metal foil, and an inner layer composed of a heat-fusible resin,
As the inner layer, a resin layer having a melt viscosity of 150 Pa · sec or more and 900 Pa · sec or less under dry nitrogen at 170 ° C. and a rotation speed of 20 rpm and having a thickness of 20 μm or more is provided.

That is, as the inner layer 4, the battery packaging material of the present invention can be manufactured by laminating each layer using the inner 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 laminated body in which the outer layer 1, the adhesive layer 2, and the intermediate layer 3 are laminated in order (hereinafter, may be referred to as “laminated body A”) is formed. Specifically, the laminate A is formed by applying an adhesive used for forming the adhesive layer 2 on the outer layer 1 or the intermediate layer 3 whose surface is subjected to chemical conversion treatment, if necessary, by gravure coating, roll coating After applying and drying by a coating method such as a method, the intermediate layer 3 or the outer layer 1 can be laminated and the adhesive layer 2 can be cured by a dry lamination method.

Next, the inner layer 4 is laminated on the intermediate layer 3 of the laminate A. When the inner layer 4 is directly laminated on the intermediate layer 3, the resin component constituting the inner layer 4 may be applied on the intermediate layer 3 of the laminate A by a method such as gravure coating or roll coating. When the adhesive layer 5 is provided between the intermediate layer 3 and the inner layer 4, for example, (1) a method of laminating the adhesive layer 5 and the inner layer 4 on the intermediate layer 3 of the laminate A by coextrusion. (Co-extrusion lamination method), (2) Separately, a laminate in which the adhesive layer 5 and the inner layer 4 are laminated, and this is laminated on the intermediate layer 3 of the laminate A by a thermal lamination method, (3) Lamination An adhesive for forming the adhesive layer 5 is laminated on the intermediate layer 3 of the body A by an extrusion method, a solution-coated high temperature drying or baking method, and the like is formed in advance on the adhesive layer 5 in a sheet form. (4) Adhesive layer while pouring the molten adhesive layer 5 between the intermediate layer 3 of the laminate A and the inner layer 4 previously formed into a sheet shape. 5 to laminate the laminate A and the inner layer 4 through Chi lamination method) and the like.

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

As described above, surface coating layer provided as necessary / outer layer 1 / adhesive layer 2 provided as needed / intermediate layer 3 having a surface subjected to chemical conversion treatment as needed / provided as needed A laminate composed of the adhesive layer 5 / inner layer 4 is formed. In order to strengthen the adhesiveness of the adhesive layer 2 and the adhesive layer 5 provided as necessary, a hot roll contact type, a hot air type, You may use for near- or far-infrared type heat processing. Examples of such heat treatment conditions include 150 ° C. or more and 250 ° C. or less and 1 minute or more and 5 minutes or less.

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

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

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

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

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples. In Examples and Comparative Examples, the melting point and melt viscosity of the resin constituting the inner layer are values measured by the following methods, respectively.
<Measurement of melting point>
It is a value measured by the DSC method in accordance with JIS K6921-2 (ISO 1873-2.2: 95).
<Measurement of melting temperature>
Using MiniLab manufactured by HAAKE, a melt viscosity of 7.5 g of a resin sample was measured at 170 ° C. and a rotation speed of 20 rpm under dry nitrogen.

<Examples 1 to 6 and Comparative Examples 1 to 4>
On a nylon film (thickness 25 μm) as an outer layer, an intermediate layer made of aluminum foil (thickness 30 μm) subjected to chemical conversion treatment on both surfaces was laminated by a dry laminating method. Specifically, an adhesive (polyol compound and aromatic isocyanate compound) was applied to one surface of the aluminum foil, and an adhesive layer (thickness 3 μm) was formed on the intermediate layer. Subsequently, after laminating the adhesive layer and the outer layer on the intermediate layer, an aging treatment was carried out at 40 ° C. for 24 hours to prepare an outer layer / adhesive layer / intermediate layer laminate. In addition, the chemical conversion treatment of the aluminum foil used as the intermediate layer is performed by roll coating a treatment liquid composed of a phenol resin, a chromium fluoride compound, and phosphoric acid so that the coating amount of chromium is 10 mg / m ² (dry weight). The coating was performed on both surfaces of the aluminum foil by the method and baked for 20 seconds under the condition that the film temperature was 180 ° C. or higher.

Next, in Examples 1, 3 to 6 and Comparative Examples 1 to 4, a carboxylic acid-modified polypropylene (disposed on the intermediate layer side) as a second heat-fusible resin layer on the intermediate layer of the laminate, The outer layer / adhesive layer / intermediate layer / second heat-fusible resin layer / first heat-fusible resin layer by coextruding random polypropylene (innermost layer) as the first heat-fusible resin layer Was obtained. In Example 2, the outer layer / adhesive layer / intermediate layer / first layer is obtained by melt-extruding random polypropylene (the innermost layer) as the first heat-fusible resin layer on the intermediate layer of the laminate. 1 A battery packaging material having a heat-sealable resin layer laminated thereon was obtained. The carboxylic acid-modified polypropylene as the second heat-fusible resin layer and the random polypropylene as the first heat-fusible resin layer have melting points, melt viscosities, and thicknesses shown in Table 1, respectively.

<Examples 7 and 8 and Comparative Examples 5 and 6>
In the same manner as in Examples 1 to 6 and Comparative Examples 1 to 4, laminates of outer layer / adhesive layer / intermediate layer were produced. Next, in Examples 7 and 8, a three-layer polypropylene film having the melting point, melt viscosity, and thickness shown in Table 2 (first heat-fusible resin layer / second heat-fusible resin layer / (Having a laminated structure of a third heat-fusible resin layer). Next, the third sealant side of the polypropylene film and the intermediate layer of the laminate are adhered using an adhesive, and the outer layer / adhesive layer / intermediate layer / adhesive layer / third heat-fusible resin layer. A battery packaging material in which / second heat-fusible resin layer / first heat-fusible resin layer was laminated was obtained. In addition, in Example 7 and Comparative Example 5, the adhesive layer between the intermediate layer and the third heat-fusible resin layer (first heat-fusible resin layer in Comparative Examples 5 and 6) is a carboxylic acid-modified polypropylene. (15 μm), Example 8 and Comparative Example 6 were formed using a resin (3 μm) obtained by crosslinking an epoxy resin with an acid-modified polypropylene resin. The polypropylene film having a three-layer structure of Example 7 and Example 8 was a three-layer co-pressed film of random polypropylene (2.5 μm) / block polypropylene (20 μm) / random polypropylene (2.5 μm). The polypropylene film having the three-layer structure and the intermediate layer of the laminate were laminated by the sandwich lamination method in Example 7, and were laminated by the dry lamination method in Example 8.

On the other hand, in Comparative Examples 5 and 6, polypropylene films having melting points, melt viscosities and thicknesses shown in Table 2 were prepared. Next, the said polypropylene film and the intermediate | middle layer of the said laminated body are adhere | attached using an adhesive agent (2 liquid curing type polyurethane adhesive, thickness is as Table 2), and outer layer / adhesive layer / intermediate A battery packaging material in which a layer / adhesive layer / first heat-fusible resin layer was laminated was obtained.

<Insulation evaluation>
The battery packaging materials of Examples 1 to 8 and Comparative Examples 1 to 6 were evaluated for insulation properties according to the following procedure. The battery packaging material was cut into 60 mm (MD direction) × 60 mm (TD direction) sheet pieces. Next, these sheet pieces were folded in the MD direction, and two opposing sides were heat-sealed with a width of 7 mm to prepare a pouch-type exterior body having an opening on one side. Next, the obtained exterior body is sealed with a lithium ion battery main body including cells so that the metal terminal extends to the outside from one side of the opening, and the opening is formed while holding the metal terminal with the electrolytic solution. A lithium ion battery was produced by hermetically sealing with a width of 3 mm. At this time, the heat sealing was performed under conditions of a surface pressure of 1.0 MPa, a sealing temperature of 170 ° C., and a sealing time of 3.0 seconds. Next, the insulation evaluation test with respect to foaming was implemented using the insulation resistance testing machine 3154 made from HIOKI. First, 10 lithium ion batteries are prepared, and one terminal of the tester is connected to the negative electrode terminal of each lithium ion battery, and the other terminal is connected to the peripheral heat seal portion of the battery exterior material with an intermediate layer of aluminum. Each was connected so as to contact the foil. Next, a voltage of 25 V was applied between the testers, and after 5 seconds, a test piece having a resistance value of 200 MΩ or more and 7 or more was regarded as acceptable (OK). Moreover, the thing less than 7 was set as the rejection (NG). The results are shown in Tables 1 and 2. In Tables 1 and 2, the parentheses in the insulation evaluation indicate actual measurement values of the number of resistance values of 200 MΩ or more among the 10 lithium ion batteries. For example, in Example 1, 8 out of 10 have a resistance value of 200 MΩ or more.

From the results shown in Table 1 and Table 2, the inner layer is a resin layer having a thickness of 20 μm or more formed of a resin having a melt viscosity of 150 Pa · sec or more and 900 Pa · sec or less under dry nitrogen at 170 ° C. and a rotation speed of 20 rpm. In the battery packaging materials of Examples 1 to 8 provided with (the second heat-fusible resin layer in Examples 1, 3 to 8, and the first heat-fusible resin layer in Example 2), the insulating material It turns out that it is excellent in. On the other hand, the battery packaging materials of Comparative Examples 1 to 6 having no resin layer having such a specific melt viscosity in the inner layer were inferior in insulation properties to Examples 1 to 8.

DESCRIPTION OF SYMBOLS 1 ... Outer layer 2 ... Adhesive layer 3 ... Intermediate | middle layer 4 ... Inner layer 41 ... 1st heat-fusion resin layer 42 ... 2nd heat-fusion resin layer 43 ... 3rd heat-fusion resin layer 5 ... Adhesion layer

Claims

In the thickness direction, in order, a laminate comprising an outer layer, an intermediate layer composed of a metal foil, and an inner layer composed of a heat-fusible resin,
The inner layer includes a resin layer having a thickness of 20 μm or more, which is made of a resin having a melt viscosity of 150 Pa · sec or more and 900 Pa · sec or less at 170 ° C. and a rotation speed of 20 rpm under dry nitrogen. material.
The inner layer is composed of one layer of the first heat-fusible resin layer,
The first heat-fusible resin layer is made of polypropylene,
The first heat-fusible resin layer is the resin layer;
The battery packaging material according to claim 1.
The inner layer is composed of two layers: a first heat-fusible resin layer as an outermost layer opposite to the intermediate layer, and a second heat-fusible resin layer adjacent to the first heat-fusible resin layer. Configured,
The first heat-fusible resin layer is made of polypropylene,
The second heat-fusible resin layer is the resin layer;
The battery packaging material according to claim 1.
The inner layer includes a first heat-fusible resin layer as an outermost layer opposite to the intermediate layer, a second heat-fusible resin layer adjacent to the first heat-fusible resin layer, and the first layer 2 is composed of three layers of a heat-fusible resin layer and a third heat-fusible resin layer adjacent thereto,
The first heat-fusible resin layer is made of polypropylene,
At least one of the second heat-fusible resin layer and the third heat-fusible resin layer is the resin layer;
The battery packaging material according to claim 1.
5. The battery according to claim 3, wherein the first heat-fusible resin layer is made of polypropylene having a melt viscosity of 120 Pa · sec or less at 170 ° C. and a rotation speed of 20 rpm under dry nitrogen. Packaging materials.
The battery packaging material according to any one of claims 1 to 5, wherein the total thickness of the inner layer is 50 µm or less.
The battery packaging material according to any one of claims 1 to 6, further comprising an adhesive layer between the intermediate layer and the inner layer.
A battery in which a battery element including a positive electrode, a negative electrode, and an electrolyte is sealed with a package formed of the battery packaging material according to any one of claims 1 to 7.
In order in the thickness direction, comprising a step of obtaining a laminate comprising an outer layer, an intermediate layer composed of a metal foil, and an inner layer composed of a heat-fusible resin,
Production of a packaging material for a battery, in which a resin layer having a melt viscosity of 150 Pa · sec or more and 900 Pa · sec or less and having a thickness of 20 μm or more is provided as the inner layer under dry nitrogen at 170 ° C. and a rotation speed of 20 rpm. Method.