CN110281612A - Battery exterior laminated body, battery exterior body and battery - Google Patents

Abstract

The present invention provides a novel battery exterior laminate that can be thinned, has excellent characteristics, and can be manufactured with high yield and high productivity. The battery exterior laminate is a battery exterior laminate comprising at least a first base material layer, a first adhesive layer, a first anticorrosion layer, a stainless steel foil, and a second base material layer in this order, and is characterized in that In that, the first substrate layer is a layer made of polyolefin, and the first adhesive layer is composed of 100 parts by mass of acid-modified polyolefin resin (A) and 1 to 20 parts by mass of a plurality of A layer composed of an epoxy-based compound (B) adhesive.

Description

Laminate for battery exterior, battery exterior, and battery

This application is a divisional application of a Chinese patent application with a filing date of August 3, 2016, a Chinese patent application number of 201610629152.7, and an invention title of "Laminated body for battery exterior packaging, battery exterior body, and battery", and this application requires the enjoyment of Priority of Japanese applications with application numbers 2015-184343 and 2016-116658.

technical field

The present invention relates to a battery exterior laminate that is excellent as an exterior of secondary batteries, capacitors, and the like, and a battery exterior and battery obtained using the laminate.

Background technique

Along with the improvement of environmental awareness and the effective use of natural energy such as sunlight and wind power, secondary batteries such as lithium-ion batteries and capacitors such as electric double layer capacitors are attracting attention as storage batteries for electric energy storage.

For the purpose of size reduction and weight reduction, as the exterior body used for these batteries, a battery exterior laminated body in which a metal foil and a resin layer are laminated is used. Such a battery exterior laminate is molded into a disk shape having a concave portion by drawing molding or the like, and this is used as the exterior body container body.

In addition, in the same manner as the above-mentioned exterior body container main body, the battery exterior laminate was molded to obtain the exterior body lid. After accommodating the battery body in the concave portion of the container body of the exterior body, the exterior body cover is superimposed so as to cover the stored battery body, and the edge portion between the container body and the exterior body lid is bonded to obtain a battery in the exterior body. Stores the battery with the battery body.

For example, Patent Document 1 discloses a battery exterior laminate in which a base material layer, an aluminum foil, and an innermost layer composed of a polypropylene or polyethylene layer are laminated in this order.

prior art literature

patent documents

Patent Document 1: JP-A-2012-33393

Contents of the invention

The technical problem to be solved in the present invention

As the fields of application of batteries such as secondary batteries expand, the development of small and large-capacity batteries is being promoted. Similarly, in the laminated body for battery exterior, while maintaining excellent characteristics, such as mechanical strength, water resistance, and chemical resistance (electrolyte solution resistance), thinning of the laminated body itself is aimed at. Generally, the mechanical strength, water resistance, chemical resistance (electrolyte solution resistance), and light-shielding properties of the battery exterior laminate are mainly secured by inorganic layers such as metal foil in the battery exterior laminate. As the metal foil, aluminum foil excellent in workability is widely used (see Patent Document 1).

However, since aluminum foil is excellent in processability compared with other metal foils, it is possible to manufacture a laminated body with high yield, but it is inferior to other metal foils in mechanical strength such as puncture strength. Therefore, in order to obtain mechanical strength, the thickness of the aluminum foil cannot be kept below a certain level, and it is difficult to reduce the thickness of the laminated body for battery exterior under the current situation of using the aluminum foil.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a battery exterior laminate that can be thinned and has excellent various properties.

Technical means to solve technical problems

The inventors of the present invention conducted repeated studies to achieve the above object, and as a result, adopted a configuration in which a thin film can be reduced while ensuring mechanical strength such as puncture strength by using stainless steel foil instead of aluminum foil. However, it has been found that when a battery exterior laminate is manufactured using stainless steel foil, there are technical problems in surface defects and electrolytic solution resistance, which are considered to be caused by poor adhesion that has not been found in conventional aluminum foils. Then, the inventors of the present invention conducted intensive studies and succeeded in newly discovering an adhesive that can properly bond a stainless steel foil surface-treated with an anticorrosion agent to a substrate layer, and completed the present invention.

That is, the present invention adopts the following constitution:

A first aspect of the present invention is a laminate for battery exterior, which is a battery comprising at least a first base material layer, a first adhesive layer, a first anticorrosion layer, a stainless steel foil, and a second base material layer in this order The exterior laminate is characterized in that the first base material layer is a layer composed of polyolefin, and the first adhesive layer is composed of 100 parts by mass of acid-modified polyolefin resin (A) and 1 ~20 parts by mass of an adhesive of compound (B) having a plurality of epoxy groups.

The compound having multiple epoxy groups is preferably a novolak epoxy resin (phenol novolak typeepoxy resin).

The epoxy equivalent of the novolac epoxy resin is preferably 100-300.

The epoxy novolak resin preferably has a bisphenol A structure.

The first anticorrosion layer preferably contains a metal halide compound.

The metal halide compound is preferably a chloride or fluoride of iron, chromium, manganese or zirconium.

The first anticorrosion layer preferably contains a resin having a polyvinyl alcohol skeleton, a fluorinated metal compound, and a phosphoric acid compound.

The thickness of the stainless steel foil is preferably 10 to 30 μm.

The first substrate layer is preferably homopolypropylene or block polypropylene.

A second aspect of the present invention is a battery exterior body comprising the battery exterior laminate of the first aspect, characterized in that it has an internal space for accommodating a battery, and the first battery exterior laminate has a battery exterior. A substrate layer side is the inner space side.

A third aspect of the present invention is a battery comprising the battery exterior body of the second aspect.

Invention effect

According to the present invention, it is possible to provide a battery exterior laminate which has excellent characteristics and can be manufactured with high yield and high productivity. In addition, the battery exterior laminate of the present invention can be thinned.

Description of drawings

FIG. 1 is a schematic cross-sectional view showing a first embodiment of a battery exterior laminate of the present invention.

Fig. 2 is a perspective view showing an example of a secondary battery manufactured using the battery exterior laminate of the present invention.

3 is a perspective view showing a process of manufacturing a secondary battery using the battery exterior laminate of the present invention.

4 is a perspective view showing a process of manufacturing a secondary battery using the battery exterior laminate of the present invention.

Detailed ways

Hereinafter, the present invention will be described based on preferred embodiments. However, this embodiment is a more specific description of the gist of the invention, and does not limit the present invention unless otherwise specified.

[Laminate for battery exterior]

The battery exterior laminate (hereinafter sometimes simply referred to as "laminate") according to the first aspect of the present invention has at least a first base material layer, a first adhesive layer, a first anticorrosion layer, a stainless steel foil, and A battery exterior laminate made of a second base material layer, the first base material layer is a layer made of polyolefin, and the first adhesive layer is made of an acid-modified polyolefin resin containing 100 parts by mass (A) and the layer which consists of 1-20 mass parts of compounds (B) which have many epoxy groups by mass parts.

FIG. 1 is a cross-sectional view showing a schematic structure of a battery exterior laminate 10 according to an embodiment of the present invention.

The laminated body 10 of the present embodiment includes a first base material layer 11, a first adhesive layer 12, a first anticorrosion layer 13, a stainless steel foil 14, a second anticorrosion layer 16, a second adhesive layer 17, The second substrate layer 15 is formed.

That is, the laminated body 10 of the present embodiment has a seven-layer structure including the first anticorrosion layer 13 and the second anticorrosion layer 16 formed on both surfaces of the stainless steel foil 14, the first anticorrosion layer The first base layer 11 laminated on the layer 13 via the first adhesive layer 12 , and the second base layer 15 laminated on the second anticorrosion layer 16 via the second adhesive layer 17 .

Each layer will be described in detail below.

The first base material layer 11 is a layer made of polyolefin. Examples of layers made of polyolefins include polyethylene, polypropylene, poly-1-butene, polyisobutylene, polyethylene, random copolymers of propylene and ethylene or α-olefins, and embeddings of propylene and ethylene or α-olefins. segment copolymers, etc.

Among them, homopolypropylene (propylene homopolymer; hereinafter sometimes referred to as "homopolyPP"), propylene-ethylene block copolymer (hereinafter Polypropylene-based resins such as "block PP" sometimes called "block PP"), random copolymers of propylene-ethylene (hereinafter sometimes called "random PP"). Among them, homopolymer PP or block PP is more preferable, and block PP is particularly preferable because of its excellent mechanical strength.

The first substrate layer 11 may be a single-layer structure or a multi-layer structure.

The melting point of the polyolefin layer used for the first base material layer 11 is not particularly limited as long as the battery exterior laminate 10 has the required heat resistance.

For example, the thickness of the first base material layer 11 may be 1 to 30 μm.

The first adhesive layer 12 is a layer composed of an adhesive containing 100 parts by mass of an acid-modified polyolefin resin (A) and 1 to 20 parts by mass of a compound (B) having a plurality of epoxy groups.

The above laminated body for battery exterior requires various properties such as mechanical strength, water resistance, and chemical resistance (electrolyte solution resistance). Most of these characteristics are performed by the metal foil in the battery exterior laminate, and the metal foil of the battery exterior plays a very important role from the viewpoint of battery durability. In addition, in order to prevent the metal foil from deteriorating due to rust or the like when the battery is used, a metal foil that has been subjected to a rust-proof treatment is often used.

The constitution of an anticorrosion treatment agent (anticorrosion layer) having a good anticorrosion effect is widely known for conventionally used aluminum foil.

On the other hand, in the present invention, stainless steel foil is used in order to achieve both thin film and mechanical strength (puncture strength, etc.). It is well known that among metals, stainless steel is less likely to rust, but it is preferable to perform antirust treatment in the same manner as conventionally for stainless steel foil for battery exterior laminates that can be used under extreme conditions such as contact with electrolyte. Therefore, the antirust treatment agent capable of imparting a good antirust effect to stainless steel foil may have a different composition from the conventional antirust treatment agent for aluminum foil.

However, as a result of providing the first anticorrosion layer composed of the antirust treatment agent for stainless steel foil on the surface of the stainless steel foil, the surface of the first anticorrosion layer and the second anticorrosion layer cannot be bonded well with the conventional adhesives. On the surface of a substrate layer, it is found that surface defects will be generated due to poor adhesion.

Here, the inventors of the present invention conducted further studies and found that 100 parts by mass of An adhesive comprising an acid-modified polyolefin resin (A) and 1 to 20 parts by mass of a compound (B) having a plurality of epoxy groups.

Then, by using the first base material layer, the first adhesive layer made of this adhesive, the first anti-corrosion layer and the stainless steel foil, the following effects can be achieved: (1) the mechanical strength is improved by the stainless steel foil ( puncture strength, etc.) and achieve thinning; (2) improve the anti-rust effect of stainless steel foil through the first anti-corrosion layer, and thus improve durability; (3) improve the mechanical strength (peel strength, etc.) ), reduce the occurrence of surface defects caused by poor adhesion when manufacturing laminates, and improve yield.

·glue

In the present invention, the adhesive forming the first adhesive layer 12 contains 100 parts by mass of the acid-modified polyolefin resin (A) and 1 to 20 parts by mass of the compound (B) having a plurality of epoxy groups.

Hereinafter, the acid-modified polyolefin resin (A) may be referred to as "(A) component", and the compound (B) which has several epoxy groups may be referred to as "(B) component".

(Acid-modified polyolefin resin (A))

In the present invention, the acid-modified polyolefin resin (A) is a polyolefin resin modified with an unsaturated carboxylic acid or a derivative thereof, and the polyolefin resin has an acid functional group such as a carboxyl group or a carboxylic acid anhydride group.

(A) The component is obtained by modification|denaturation of the polyolefin resin with unsaturated carboxylic acid or its derivative(s), copolymerization of an acid functional group containing monomer, and an olefin, etc. Among these, as (A) component, the thing obtained by acid-modifying polyolefin resin is preferable.

As an acid modification method, in the presence of a radical polymerization initiator such as an organic peroxide or an aliphatic azo compound, graft modification of a polyolefin resin and an acid-functional group-containing monomer by melt-kneading is exemplified. .

Examples of the polyolefin-based resin include polyethylene, polypropylene, poly-1-butene, polyisobutylene, random copolymers of propylene and ethylene or α-olefin, and block copolymers of propylene and ethylene or α-olefin. Among them, homopolypropylene (propylene homopolymer; hereinafter sometimes referred to as "homoPP"), propylene-ethylene block copolymers (hereinafter sometimes referred to as "block PP"), and propylene-ethylene random copolymers are preferred. (hereinafter referred to as "random PP") and other polypropylene-based resins, and random PP is particularly preferred.

Examples of the olefins in the case of copolymerization include olefin monomers such as ethylene, propylene, 1-butene, isobutylene, 1-hexene, and α-olefin.

The acid functional group-containing monomer is a compound having an ethylenic double bond, a carboxyl group, or a carboxylic acid anhydride group in the same molecule, and examples thereof include various unsaturated monocarboxylic acids, dicarboxylic acids, or anhydrides of dicarboxylic acids.

Acrylic acid, methacrylic acid, maleic acid, nadic acid, fumaric acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, etc. , tetrahydrophthalic acid, endobicyclo[2.2.1]-5-heptene-2,3-dicarboxylic acid (5-norbornene-2,3-dicarboxylic acid (endic acid)) and other α,β- unsaturated carboxylic acid monomer.

Examples of acid functional group-containing monomers having a carboxylic anhydride group (carboxylic anhydride group-containing monomers) include maleic anhydride, nadic anhydride, itaconic anhydride, citraconic anhydride, norbornenedioic anhydride and other unsaturated dicarboxylic anhydride monomers. body.

These acid functional group-containing monomers may be used individually by 1 type or in combination of 2 or more types in (A) component.

Among them, the acid functional group-containing monomer is preferably an acid functional group-containing monomer having an acid anhydride group, more preferably a carboxylic acid anhydride group-containing monomer, and particularly preferably maleic anhydride, because of its high reactivity with the component (B) described later.

When part of the acid functional group-containing monomer used in the acid modification is unreacted, in order to prevent the reduction of the adhesive force caused by the unreacted acid functional group-containing monomer, it is preferable to remove the unreacted acid functional group-containing monomer The substance is used as (A) component.

In (A) component, it is preferable that it is 50 mass parts or more of a polyolefin resin or an olefin-derived component with respect to 100 mass parts of total amounts of (A) component.

(A) The melting point of the component is not particularly limited.

For example, the adhesive used in the present invention does not contain an organic solvent, and when the adhesive is formed by melting and kneading the component (A) and the component (B) described later, the melting point of the component (A) is preferably 100° C. to 180°C. An adhesive layer composed of such an adhesive can be suitably used as an adhesive layer for thermal lamination.

By using component (A) having a melting point in the above-mentioned range, it is possible to melt-knead component (A) and the after (B) component. Moreover, when using melt kneading to make (A) component react with (B) component mentioned later, it is preferable that the melting point of (B) component is lower than (A) component, and by using (A) component which has the melting point of the said range , the degree of freedom of selection of the (B) component can be increased.

In addition, as mentioned above, the melting point of the component (A) is preferably higher than the melting point of the component (B) described later, more preferably the melting point of the component (A) is higher than the melting point of the component (B) by 10°C or more, further preferably 20°C or more, It is particularly preferably higher than 30°C. Since the melting point of component (A) is sufficiently higher than that of component (B), when melt kneading is performed, component (B) melts first and penetrates into component (A) which maintains the shape of the resin, and component (A) and component (B) The reaction proceeds uniformly, and as a result, good durability can be obtained.

On the other hand, when the first adhesive layer 12 is an adhesive layer for dry lamination, the melting point of the component (A) is preferably 50 to 100°C. By providing a layer composed of an adhesive containing a polyolefin having a relatively low melting point of 50 to 100°C, it is possible to use a relatively low temperature that does not cause deformation on the stainless steel foil, that is, at a temperature near or below 100°C. , bonding the stainless steel foil with the first anti-corrosion layer and the first substrate layer via the first adhesive layer.

Among them, maleic anhydride-modified polypropylene is preferred as the component (A) from the viewpoint of adhesiveness and moderate melting point.

(compound (B) having a plurality of epoxy resins)

(B) A component is a compound which has several epoxy groups. (B) The component may be a low-molecular compound or a high-molecular compound. It is preferable that (B) component is a polymer compound (resin) from a viewpoint of favorable miscibility with (A) component. On the other hand, it is preferable that (B) component is a low molecular weight compound from a viewpoint of the solubility to a solvent being favorable.

(B) The structure of the component is not particularly limited as long as it has a plurality of epoxy groups, for example, phenoxy resin synthesized from bisphenols and epichlorohydrin, novolak epoxy resin, bisphenol epoxy resin, etc. . Among them, since the epoxy content per molecule is high, especially since a dense crosslinked structure can be formed with the component (A), novolac epoxy resin is preferably used.

The novolac epoxy resin in the present invention is a compound having an epoxy novolak resin obtained by acid condensation of phenol and formaldehyde as a basic structure, and an epoxy group is introduced into a part of the structure. The amount of epoxy groups introduced per molecule in the novolac epoxy resin is not particularly limited, but by reacting epoxy-based raw materials such as epichlorohydrin with the novolak epoxy resin, the phenolic substances present in large quantities in the novolac epoxy resin A large number of epoxy groups are introduced into the hydroxyl group, so it is usually a multifunctional epoxy resin.

Among them, as the novolac epoxy resin, a bisphenol A novolak epoxy resin having a novolak structure as a basic skeleton and a bisphenol A structure is preferable. In addition, the bisphenol A structure in the novolac epoxy resin may be a structure derived from bisphenol A, and groups such as epoxy group-containing groups may be used to replace the hydroxyl groups at both ends of bisphenol A.

As an example of a bisphenol A novolak epoxy resin, the resin represented by following General formula (1) is mentioned.

[chemical formula 1]

In formula (1), R ¹ to R ⁶ are independently hydrogen atoms or methyl groups, n is an integer of 0 to 10, and R ^X is a group having an epoxy group.

In formula (1), R ¹ to R ⁶ are independently hydrogen atoms or methyl groups. When n is an integer of 2 or more, each of R ³ and R ⁴ may be the same or different.

Among the resins represented by the formula (1), it is preferable to satisfy at least one of the following (i) to (iii).

(i) R ¹ and R ² are both methyl;

(ii) R ³ and R ⁴ are both methyl;

(iii) R ⁵ and R ⁶ are both methyl groups.

For example, by satisfying the above (i), in formula (1), the carbon atom to which R ¹ and R ² are bonded and the two hydroxyphenyl groups to which the carbon atom is bonded constitute a structure derived from bisphenol A.

In formula (1), R ^X is a group having an epoxy group. As a group which has an epoxy group, an epoxy group, the combination of an epoxy group and an alkylene group, etc. are mentioned, Among them, a glycidyl group is preferable.

The epoxy equivalent of the bisphenol A novolac epoxy resin is preferably 100-300, more preferably 200-300. The epoxy equivalent (g/eq) is the molecular weight of an epoxy resin with one epoxy group. The smaller the value, the more epoxy groups in the resin. By using an epoxy resin with a small epoxy equivalent, even if the amount of novolac epoxy resin added is relatively small, the adhesion between the novolak epoxy resin and the adherend is good, and the novolac The epoxy resin is sufficiently cross-linked with the acid-modified polyolefin resin.

As such bisphenol A novolak epoxy resins, jER154, jER157S70, jER-157S65 manufactured by Mitsubishi Chemical Corporation; EPICLON N-730A, EPICLON N-740, EPICLON N-770, EPICLON N- 775 (the above are all trade names) and other commercially available products.

It is considered that by using the above-mentioned epoxy resin, both the acid functional group of the (A) component and the epoxy group of the (B) component are due to the adhesiveness to the adherend (especially the functional group such as a hydroxyl group possessed by the adherend). Functional groups function, and thus excellent adhesion to the first base material layer 11 and the first anticorrosion layer 13 can be achieved.

In addition, it is also considered that a part of the acid functional group of (A) component reacts with a part of the epoxy group of (B) component to form a crosslinked structure of (A) component and (B) component. According to this crosslinked structure, the resin The strength is strengthened, and good durability is obtained while obtaining excellent adhesion.

In the adhesive used in the present invention, it is preferable to contain 1 to 20 parts by mass of the component (B) with respect to 100 parts by mass of the component (A), and it is more preferable to contain 5 to 5 parts by mass of the component (B) with respect to 100 parts by mass of the component (A). 10 parts by mass, most preferably 5-7 parts by mass of (B) component with respect to 100 parts by mass of (A) component.

The adhesive used in the present invention may contain miscible additives, additional resins, plasticizers, stabilizers, colorants, and the like as necessary.

In addition, the adhesive of the present invention may further contain or may not contain an organic solvent.

An adhesive that becomes liquid by containing an organic solvent can be, for example, an adhesive suitable for dry lamination. The adhesive layer can be formed by applying and drying such a liquid adhesive on the layer as the lower layer.

On the other hand, in the absence of an organic solvent, an adhesive layer suitable for thermal lamination or the like can be formed by melt-kneading an acid-modified polyolefin resin and an epoxy resin, followed by extrusion molding or the like.

When an organic solvent is contained, the organic solvent to be used is not particularly limited as long as it can appropriately dissolve the above-mentioned resin, for example, toluene or the like can be used. The usage-amount of an organic solvent is not specifically limited, Preferably it is 3-30 mass % of solid content, More preferably, it is 5-25 mass %, More preferably, it is 10-20 mass %.

The thickness of the first adhesive layer 12 can be, for example, 0.5 to 10 μm. By setting the thickness within this range, the first base material layer 11 and the stainless steel foil 14 can be bonded with high adhesive force, and delamination can be prevented.

In this aspect, the first anticorrosion layer 13 is a layer for preventing corrosion of the stainless steel foil 14 due to rust or the like.

The first anticorrosion layer 13 preferably contains a metal halide compound, and the metal halide compound described later may be directly plated on the surface of the stainless steel foil 14 . By providing such a first anti-corrosion layer 13, a good anti-rust effect can be given to the stainless steel foil.

Among them, the first anticorrosion layer 13 further preferably contains a water-soluble resin, and is preferably formed by coating a water-soluble paint containing a water-soluble resin, a metal halide compound, and a chelating agent, followed by drying and curing.

·Water-soluble paint

(water soluble resin)

As the water-soluble resin, it is preferable to use one or more of polyvinyl alcohol-based resins and polyvinyl ether-based resins.

The polyvinyl alcohol-based resin is at least one water-soluble resin selected from polyvinyl alcohol resins and modified polyvinyl alcohol resins.

The polyvinyl alcohol resin can be produced, for example, by saponifying a polymer of a vinyl ester monomer or a copolymer thereof.

Vinyl ester monomers such as fatty acid vinyl esters such as vinyl formate, vinyl acetate, and vinyl butyrate, or aromatic vinyl esters such as vinyl benzoate, etc., as polymers of vinyl ester monomers or copolymers thereof Homopolymers or copolymers, and copolymers of other monomers that can be copolymerized with them.

Examples of other copolymerizable monomers include olefins such as ethylene and propylene, ether group-containing monomers such as alkyl vinyl ethers, diacetone acrylamide, diacetone (meth)acrylate, allyl acetoacetate, acetyl Carbonyl (ketone group)-containing monomers such as acetate, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and maleic anhydride, vinyl halides such as vinyl chloride or vinylidene chloride, and unsaturated sulfonic acids.

The degree of saponification of the polyvinyl alcohol-based resin is usually preferably 90 to 100 mol%, more preferably 95 mol% or more.

Examples of polyvinyl alcohol-based resins include alkyl ether-modified polyvinyl alcohol resins, carbonyl-modified polyvinyl alcohol resins, acetoacetyl-modified polyvinyl alcohol resins, acetamide-modified polyvinyl alcohol resins, and acrylonitrile-modified polyvinyl alcohol resins. Polyvinyl alcohol resin, carboxy-modified polyvinyl alcohol resin, silicone-modified polyvinyl alcohol resin, ethylene-modified polyvinyl alcohol resin, etc. Among them, alkyl ether-modified polyvinyl alcohol resins, carbonyl-modified polyvinyl alcohol resins, carboxyl-modified polyvinyl alcohol resins, and acetoacetyl-modified polyvinyl alcohol resins are preferable.

Commercially available polyvinyl alcohol-based resins include, for example, J-POVAL DF-20 (trade name) manufactured by Nippon VAM & POVAL Co., Ltd., CROSSMER H series (trade name) manufactured by Nippon CARBIDE Industry Co., Ltd. )Wait. One type or a mixture of two or more types of polyvinyl alcohol-based resins can be used.

Examples of polyvinyl ether resins include ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, 2-ethylhexyl vinyl ether, and cyclohexyl vinyl ether. Homopolymers or copolymers of aliphatic vinyl ethers such as norbornyl vinyl ether, allyl vinyl ether, norbornenyl vinyl ether, 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, and Copolymers of other monomers copolymerized with it, etc. Examples of other monomers that can be copolymerized with vinyl ether monomers include the same ones as other monomers that can be copolymerized with the above-mentioned vinyl ester monomers.

Especially 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 2-hydroxypropyl vinyl ether, and other monovinyl ethers of various diols or polyols, etc., which contain Polyvinyl ether-based resins of aliphatic vinyl ethers of hydroxyl groups can be suitably used in the present invention because they are water-soluble and allow a crosslinking reaction with respect to hydroxyl groups.

These polyvinyl ether resins can be produced without saponification treatment, unlike polyvinyl alcohol resins produced via vinyl ester polymers, because vinyl ether monomers can be used in the resin production (polymerization) process. In addition, a copolymer containing a vinyl ester monomer or a vinyl ether monomer, or a vinyl alcohol-vinyl ether copolymer obtained by saponification can also be used. A mixture of polyvinyl alcohol-based resins other than polyvinyl ether-based resins and polyvinyl ether-based resins may also be used.

As the water-soluble resin, only one of polyvinyl alcohol-based resin and polyvinyl ether-based resin may be used, or both may be used in combination.

(metal halide compound)

The metal halide compound is preferably water-soluble because it needs to be mixed with the aforementioned water-soluble resin.

Examples of the metal halide compound include chromium halides, iron halides, zirconium halides, titanium halides, hafnium halides, titanium hydrohalides (Chitan Halogenated hydrochloric acid) and their salts. Examples of the halogen atom include chlorine, bromine and fluorine, preferably chlorine or fluorine. Furthermore, fluorine is particularly preferred.

Among them, as the metal halide compound, chloride or fluoride of iron, chromium, manganese or zirconium is preferable.

The metal halide compound has the effect of improving chemical resistance such as electrolyte solution resistance. That is, passivating the surface of the stainless steel foil 14 can improve the corrosion resistance to the electrolytic solution. The metal halide compound also acts to crosslink the water-soluble resin.

(chelating agent)

Water-soluble paints contain chelating agents. The chelating agent is a material that coordinates and binds to metal ions to form metal ion complexes.

The chelating agent combines the metal compound (chromium oxide, etc.) from the metal halide compound with the water-soluble resin. In order to improve the compressive strength of the first anti-corrosion layer 13, even if the thickness of the first anti-corrosion layer 13 exceeds 0.2 μm, for example, And when the thickness is less than 1.0 μm, the first anti-corrosion layer 13 will not be brittle cracked or peeled off. Therefore, the adhesive strength between the stainless steel foil 14 and the first adhesive layer 12 and the adhesive strength between the stainless steel foil 14 and the layer on the upper layer side can also be improved.

In addition, the chelating agent has the effect of making the water-soluble resin water-resistant by chemically reacting with the water-soluble resin or the metal halide compound.

As the chelating agent, for example, aminocarboxylic acid-based chelating agents, phosphonic acid-based chelating agents, hydroxycarboxylic acids, and (poly)phosphoric acid-based chelating agents can be used.

Examples of aminocarboxylic acid chelating agents include nitrilotriacetic acid (NTA), hydroxyethyliminodiacetic acid (HIDA), ethylenediaminetetraacetic acid (EDTA), and hydroxyethylethylenediaminetriacetic acid (HEDTA). , diethylenetriaminepentaacetic acid (DTPA), triethylenetetraaminehexaacetic acid (TTHA), trans-cyclohexanediaminetetraacetic acid (CyDTA), 1,2-propanediaminetetraacetic acid (1,2- PDTA), 1,3-propanediaminetetraacetic acid (1,3-PDTA), 1,4-butanediaminetetraacetic acid (1,4-BDTA), 1,3-diamino-2-hydroxypropanetetraacetic acid (DPTA-OH), ethylene glycol diethyl ether diamine tetraacetic acid (GEDTA), ethylenediamine o-hydroxyphenylacetic acid (EDHPA), SS-ethylenediamine disuccinic acid (SS-EDDS), ethylenediamine disuccinic acid (EDDS), β-alanine diacetic acid (ADA), methylglycine diacetic acid (MGDA), L-aspartic acid-N,N-diacetic acid (ASDA), L-glutamic acid-N,N - Diacetic acid (GLDA), N,N'-bis(2-hydroxyphenyl)ethylenediamine-N,N'-diacetic acid (HBEDDA).

The phosphonic acid chelating agent is not particularly limited as long as it is a compound having a -P(=O)(OH) ₂ structure derived from phosphonic acid (HP(=O)(OH) ₂ ), and examples thereof include N, N,N-trimethylenephosphonic acid (NTMP), 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), ethylenediamine-N,N,N',N'-tetramethylenephosphine acid (EDTMP), diethylenetriaminepentamethylenephosphonic acid (DTPMP), 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC), nitrilotris(methylenephosphine acid) (NTMP).

Examples of the hydroxycarboxylic acid-based chelating agent include glycolic acid, citric acid, malic acid, gluconic acid, glucoheptonic acid, and the like.

Examples of (poly)phosphoric acid-based chelating agents include phosphoric acid, metaphosphoric acid, tripolyphosphoric acid, tetrapolyphosphoric acid, pyrophosphoric acid, orthophosphoric acid, hexametaphosphoric acid, and salts thereof.

As a commercially available chelating agent, for example, aminocarboxylic acid chelating agents such as CHELEST PD-4H (PDTA); CHELEST PH-540 (EDTMP), CHELEST PH-210 (HEDP), CHELEST PH-320 (NTMP), CHELEST PH-430 (PBTC) and other phosphonic acid chelating agents (all of the above are chelating agents made by CHELEST (KK), marked as trade names).

Among them, as the chelating agent, phosphoric acid-based chelating agents (phosphoric acid compounds) such as phosphonic acid-based chelating agents and (poly)phosphoric acid-based chelating agents are preferred, and phosphonic acid-based chelating agents are more preferred.

The water-soluble resin is preferably 3 to 30% by mass, more preferably 5 to 20% by mass, and still more preferably 10 to 15% by mass in the total solid content of the water-soluble paint. In addition, the metal halide compound is preferably 20 to 60% by mass, more preferably 30 to 55% by mass, and still more preferably 40 to 50% by mass in the total solid content of the water-soluble paint. The chelating agent is preferably 20 to 60% by mass, more preferably 30 to 50% by mass, and still more preferably 35 to 45% by mass in the total solid content of the water-soluble paint.

Water-soluble paints can be produced by dissolving water-soluble resins, metal halide compounds, and chelating agents in solvents containing water. As the solvent, water is preferred.

The solid content concentration in the water-soluble paint can be appropriately determined in consideration of the applicability of the first anticorrosion layer 13 and the like, and is generally 0.1 to 10% by mass.

The thickness of the first anticorrosion layer 13 is preferably greater than 0.05 μm, more preferably greater than 0.1 μm. By setting the thickness of the first anticorrosion layer 13 to 0.05 μm or more, sufficient corrosion resistance can be imparted to the battery exterior laminate 10 and the bonding strength between the stainless steel foil 14 and the first adhesive layer 12 can be improved. And the bonding strength between the stainless steel foil 14 and the first substrate layer 11 .

In addition, the thickness of the first anticorrosion layer 13 is preferably 1.0 μm or less, more preferably 0.5 μm or less. By setting the thickness of the first anticorrosion layer 13 to 1.0 μm or less, the bonding strength between the stainless steel foil 14 and the first adhesive layer 12 can be improved, and the material cost can be suppressed.

The stainless steel foil 14 is a metal foil made of stainless steel, and is made of, for example, austenitic, ferritic, or martensitic stainless steel. As the austenite type, there are SUS304, 316, 301, etc., as the ferrite type, there are SUS430, etc., and as the martensite type, there are SUS410, etc.

Compared with other metal foils such as aluminum foil, the stainless steel foil 14 has higher mechanical strength such as puncture strength and tensile strength, so even when the thickness is 40 μm or less, it can give the battery exterior laminate 10 sufficient mechanical strength. As a result, the stainless steel foil 14 and the laminated body 10 as a whole can be thinned.

In addition, since the mechanical strength is high, when the concave portion is formed by drawing, the occurrence of pin holes can be reduced, and as a result, the leakage of the contents sealed in the laminate (such as battery fluid leakage) can be reduced. Moreover, since the stainless steel foil 14 is excellent in corrosion resistance compared with other metal foils, deterioration by corrosion can be prevented favorably.

The thickness of the stainless steel foil 14 is preferably 100 μm or less, preferably 5 to 40 μm, more preferably 5 to 30 μm, particularly preferably 10 to 20 μm. By setting it as more than the said lower limit, sufficient mechanical strength is given to the battery exterior laminated body 10, and when used for batteries, such as a secondary battery, the durability of a battery can be improved. Moreover, by making the thickness of the stainless steel foil 14 below the said upper limit, the laminated body 10 for battery exteriors can be made thin enough, and sufficient drawing processability can be given.

The second anticorrosion layer 16 has the same structure as the first anticorrosion layer 13 .

The second adhesive layer 17 may have the same structure as the first adhesive layer 12 , or may be a layer made of an adhesive such as a general urethane adhesive or epoxy adhesive. The thickness of the second adhesive layer 17 can be set to, for example, 0.5 to 10 μm. By setting the thickness into this range, the second base material layer 15 and the stainless steel foil 14 can be bonded with high adhesive force, and delamination can be prevented.

The second base material layer 15 is not particularly limited as long as it has sufficient mechanical strength, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethylene terephthalate Polyester resins such as butylene formate (PBT); polyamide resins such as nylon (Ny); olefin resins such as stretched polypropylene (OPP); polyether ether ketone (PEEK), polyphenylene sulfide (PPS), etc. composed of synthetic resin films. Among them, PET films are preferable.

The thickness of the second base layer 15 can be, for example, 1 to 50 μm, preferably 1 to 30 μm, and more preferably 3 to 11 μm.

The second substrate layer 15 can be a single-layer structure or a multi-layer structure. As an example of the second base material layer 15 having a multilayer structure, a double-layer film in which a polyethylene terephthalate (PET) resin film is laminated on a twin-screw stretched polyamide resin film (ONy) can be cited. . In addition, the second base material layer 15 may have a multilayer structure in which three or more films are laminated.

In addition, in the embodiment shown in FIG. 1 , the second base material layer 15 is the outermost layer. Therefore, the second base material layer can have a desired color and design by containing a resin plus a coloring agent such as a pigment.

The second base material layer 15 is preferably constituted by a single-layer or multi-layer film using a heat-resistant resin film having a melting point of 200° C. or higher. Examples of such heat-resistant resin films include PET films, PEN films, PBT films, nylon films, PEEK films, and PPS films, and PET films are particularly preferred in terms of cost. By using such a heat-resistant resin film, the heat resistance of the laminated body for battery exterior 10 can be improved, and the durability of the battery using the laminated body 10 for battery exterior can be improved.

In the laminated body 10 for battery exterior shown in FIG. On the inner side, the side that can be in contact with the electrolytic solution or the like is the side of the first base material layer 11 . Therefore, the anticorrosion layer is formed at least on the first base material layer 11 side of the stainless steel foil 14 . That is, the second anticorrosion layer 16 may be omitted from the battery exterior laminate 10 of FIG. 1 .

In the battery exterior laminate 10 shown in FIG. 1 , the second base material layer 15 is the outermost layer, but a coating layer may be formed further outside the second base material layer 15 .

The coating layer (first coating layer) is made of urethane resin, acrylic resin, polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymer resin, maleic anhydride modified polypropylene resin, polyester resin, Epoxy resin, phenol resin, phenoxy resin, fluororesin, cellulose ester resin, cellulose ether resin, polyamide resin, polyphenylene ether resin (PPE), polyphenylene sulfide resin (PPS), polyarylether resin ( PAE) and polyether ether ketone resin (PEEK) at least one resin selected from the resin group. The coating layer is preferably composed of a material excellent in heat resistance. These resins may be used alone or in combination of two or more.

The coating layer is preferably a thin-film cured layer formed by coating and drying a solvent-based paint prepared by dissolving the resin in a common organic solvent.

Formation of the coating layer can prevent surface damage of the laminated body 10 for battery exteriors while improving the insulation of the laminated body 10 for battery exteriors. In addition, even when the battery exterior laminate 10 contacts the electrolytic solution, changes in appearance (discoloration, etc.) can be prevented.

In addition, the coating layer can be colored by adding a colorant and a pigment to the solvent-based paint forming the coating layer. In addition, coloring and printing can also be added to make the coating layer display characters, graphics, images, patterns, etc., to improve the sense of design.

The thickness of the coating layer can be set to, for example, 0.1 to 20 μm, preferably 2 to 10 μm.

In the battery exterior laminate 10 shown in FIG. 1, the second base material layer 15 and the second adhesive layer 17 are directly bonded, but it may be provided on the inner side of the second base material layer 15 for improving the design. Sensitive printing layer.

The printing layer may have the same configuration as the coating layer described above.

The thickness of the battery exterior laminate 10 is preferably 10 to 500 μm, more preferably 20 to 200 μm, and even more preferably 30 to 100 μm.

Examples of the battery using the battery exterior laminate 10 include a secondary battery such as a lithium ion battery or a capacitor such as an electric double layer capacitor using an organic electrolyte as an electrolytic solution. As an organic electrolyte, generally, a carbonate such as propylene carbonate (PC), ethylene carbonate (DEC), or ethylene carbonate is used as a medium, but it is not particularly limited to these substances.

The battery exterior laminate of the present invention can be produced, for example, by a method comprising the following steps: a step of forming a first anticorrosion layer on one surface of a stainless steel foil; forming a first adhesive on the formed first anticorrosion layer. a step of an adhesive layer; and a step of arranging the first base material layer in contact with the formed first adhesive layer, and laminating the laminate.

The details will be described below.

First, the first anticorrosion layer 13 is formed on one surface of the stainless steel foil 14 .

Specifically, the above-mentioned water-soluble paint is applied on the surface of the stainless steel foil 14, followed by heating and drying. At this time, the first anti-corrosion layer 13 can only be formed by coating a water-soluble paint on one side of the stainless steel foil 14, or the second anti-corrosion layer 13 can be formed at the same time by coating a water-soluble paint on both sides of the stainless steel foil 14. Corrosion layer 16. In addition, when the second anticorrosion layer 16 is provided, the second anticorrosion layer 16 is preferably formed in a stage before the formation of the first adhesive layer 12 and the like, and is more preferably formed simultaneously with the first anticorrosion layer 13 .

In addition, when forming the first anticorrosion layer 13 and the second anticorrosion layer 16 at the same time, it is preferable to immerse the stainless steel foil 14 in a water-soluble paint, and to apply the water-soluble paint to both surfaces of the stainless steel foil 14, followed by heating and drying. .

Next, the first adhesive layer 12 is formed on the first anticorrosion layer 13 .

Specifically, a layer made of the above-mentioned adhesive is formed on the surface of the stainless steel foil 14 on which the first anticorrosion layer 13 is provided, followed by heating and drying as necessary.

When the adhesive is a thermal lamination adhesive that does not contain an organic solvent, after reacting the two components by melt kneading (A) component and (B) component, by applying it on the first anticorrosion layer 13 and dried to form the first adhesive layer 12.

Known devices such as a single-screw extruder, a multi-screw extruder, a Banbury mixer, a plastomill, and a heated roll kneader can be used for the melt-kneading. In order to suppress the decomposition of the epoxy group during melt kneading, it is better to remove the volatile components that can react with the epoxy group, such as moisture, to the outside of the device in advance, and when the volatile components are generated during the reaction, they should be discharged outside the device at any time by degassing, etc. . When the acid-modified polyolefin resin has an acid anhydride group as an acid functional group, it is preferable because the reactivity with epoxy groups is high and the reaction can proceed under more stable conditions. The heating temperature at the time of melt-kneading is preferably selected from the range of 240 to 300°C in terms of sufficiently melting the two components without thermally decomposing them. In addition, the kneading temperature can be measured by a method such as bringing a thermocouple into contact with the adhesive resin composition in a molten state immediately extruded from a melt-kneading apparatus.

In addition, when the adhesive is an adhesive for dry lamination containing an organic solvent, after dissolving the components (A) and (B) in the organic solvent, apply the solution to the first anticorrosion layer 13 and dried to form the first adhesive layer 12. In addition, the formation of the first adhesive layer 12 can be performed as a series of steps together with the lamination step of the first base material layer 11 described later using a known dry laminator or the like.

Thereafter, the first base material layer 11 is disposed so as to be in contact with the formed first adhesive layer 12, and the laminate is stacked. Lamination is preferably dry lamination at 70 to 150°C. The pressure during dry lamination is preferably 0.1 to 0.5 MPa.

Specifically, a film constituting the first base material layer 11 is prepared in advance, and dry lamination is performed after arranging the film on the first adhesive layer. The temperature of the dry lamination is not particularly limited as long as it is a temperature at which the first base material layer 11, the first anticorrosion layer 13 and the stainless steel foil 14 are well bonded via the first adhesive layer, and it is conceivable to constitute the first bonding layer. The material or the melting point of the adhesive of the adhesive layer 12 is determined. The temperature during dry lamination is generally 70 to 150°C, preferably 80 to 120°C.

The battery exterior laminate of this aspect has a structure in which the first base material layer 11, the first anticorrosion layer 13, and the stainless steel foil 14 are bonded via the first adhesive layer 12, so that the above-mentioned dry method is used for bonding. Cascading becomes possible. Then, by using dry lamination instead of thermal lamination which requires heating over 200° C. during lamination, the temperature during lamination can be greatly reduced.

Generally, when a high temperature is applied to stainless steel foil, which has low thermal conductivity and hardly expands, deformation (curling) tends to occur in the width direction of the stainless steel foil. In the case of thermal lamination using such a stainless steel foil, heat may not be sufficiently propagated in the plane, and a portion in the width direction that does not come into contact with the thermocompression bonding roll may be generated without contacting the roll, and may be thermally damaged. Bending and wrinkles occur due to the deformation itself during pressing. In addition, when the stainless steel foil is heated to such a high temperature that deformation does not occur, productivity decreases due to a decrease in processing speed or an increase in required heat.

Therefore, when dry lamination is used in the production of the laminate for battery exterior of this aspect, occurrence of bending and wrinkles can be suppressed, and a suitable laminate for battery exterior can be produced.

In addition, the step of forming the first adhesive layer 12 and the step of arranging the first base material layer 11 for (dry) lamination can be performed as a series of steps using a known (dry) lamination apparatus.

The formation methods of the second anticorrosion layer 16, the second adhesive layer 17, and the second base material layer 15 are not particularly limited, for example, the second adhesive layer 17 is formed on the second base material layer 15 in advance A stack of layers. Afterwards, by connecting the second adhesive layer 17 with the second anticorrosion layer 16, the double-layer laminate and the first base material layer 11, the first adhesive layer 12, the first anticorrosion layer The laminated body of the layer 13, the stainless steel foil 14, and the second anticorrosion layer 16 is dry-laminated to manufacture the laminated body 10 for battery exterior which consists of seven layers.

Above, one embodiment of the present invention has been described based on the battery exterior laminate 10 shown in FIG. 1 , but the technical scope of the present invention is not limited to the above-mentioned embodiment, and various variant.

For example, a six-layer structure may be adopted without providing the second anticorrosion layer 16 .

In addition, other layers may be provided on the side of the first base material layer 11 not in contact with the first adhesive layer 12 and the side of the second base material layer 15 not in contact with the second adhesive layer 17, Thereby becoming a structure of 7 layers or more than 8 layers.

[battery exterior body]

A battery exterior body according to a second aspect of the present invention is a battery exterior body having the battery exterior laminate of the first aspect, has an internal space for accommodating a battery, and one side of the first base material layer of the battery exterior laminate is the battery exterior body. The battery exterior body on the side of the interior space. Specifically, it is obtained by molding the laminate for battery exterior of the first aspect into a desired shape so that the first base material layer faces the internal space, and sealing the ends as necessary.

The shape, size, etc. of the battery case are not particularly limited, and may be appropriately determined according to the type of battery to be used.

The battery case may be composed of one member, or may be formed by combining two or more members (for example, a container body and a lid) as described later using FIG. 2 .

[Battery]

A battery according to a third aspect of the present invention has the battery exterior body according to the second aspect.

Examples of the battery include a secondary battery such as a lithium ion battery, a capacitor such as an electric double layer capacitor, or a battery using an organic electrolyte for the electrolytic solution.

As an example, a perspective view of a secondary battery 40 is shown in FIG. 2 . The secondary battery 40 includes a lithium ion battery 27 in the battery exterior container 20 .

The battery exterior container 20 is formed by stacking the container body 30 constituted by the battery exterior laminate 10 according to the first aspect of the present invention and the cover portion 33 constituted by the battery exterior laminate 10 , and heat-sealing the peripheral portion 29 . Reference numeral 28 denotes electrode leads connected to the positive and negative electrodes of the lithium ion battery 27 .

The battery shown in Fig. 2 can be manufactured in the following manner.

First, as shown in FIG. 3( a ), the container main body 30 is obtained by making the laminated body 10 for battery exterior packaging into a disk shape having the concave portion 31 and molding it by drawing molding or the like. The depth of the recessed part 31 can be set to 2 mm or more, for example.

A lithium-ion battery (lithium-ion battery 27 in FIG. 2 ) is accommodated in the recess 31 of the container body 30 .

Next, as shown in FIG. 3( b ), the lid portion 33 composed of the battery exterior laminate 10 is superimposed on the container body 30 , and the flange portion 32 of the container body 30 and the lid portion 33 are heat-sealed. The peripheral portion 34 was removed to obtain the secondary battery 40 shown in FIG. 2 . That is, in the battery shown in FIG. 3 , by covering the upper surface of the container body 30 with the cover 33 , the recess 31 and the cover 33 form an internal space for accommodating the battery.

In addition, the battery in the present invention can also be produced in the following manner.

First, as shown in FIG. 4( a ), by drawing molding or the like, a part of one end side of the rectangular battery exterior laminate 50 in the longitudinal direction is pressed from the first base material layer side of the battery exterior laminate 50 . Then, molding is performed to obtain a molded body 55 having a concave portion 51 . The depth of the recessed part 51 can be set to 2 mm or more, for example.

Next, not shown, a lithium ion battery (lithium ion battery 27 in FIG. 2 ) is accommodated in the concave portion 51 of the molded body 55 .

Next, a fold line L extending in the short side direction of the molded body 55 is formed in a part of the other end side of the molded body 55 where the concave portion 51 is not formed, and is bent on the side of the first base material layer. At this time, in the molded body 55 , the area on the side of the recess 51 with respect to the fold line L is referred to as the “first area 551 ”, and the area opposite to the recess 51 with respect to the fold line L is referred to as the “second area 552 ”.

Next, the first base material layer on the periphery 52 of the concave portion 51 in the first region 551 and the first base material layer (peripheral edge portion 54 ) overlapping the periphery 52 in the second region 552 are superimposed. In this way, the second region 552 overlaps the recess 51 of the first region 551 .

Next, as shown in FIG. 4( b ), by heat-sealing the first base material layer around the concave portion 51 and the first base material layer in the second region 552, a secondary battery case having a battery exterior body composed of one component is obtained. battery 60. That is, in the battery shown in FIG. 4( b ), by covering the upper surface of the concave portion 51 with the second region 552 , the concave portion 51 and the second region 552 form an internal space for accommodating the battery.

Example

Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited to these examples.

[Examples 1-15, Comparative Examples 1-5]

(Embodiments 1-5)

First, a stainless steel foil with a thickness of 20 μm is prepared. Water-soluble paint (coating amount 12g/m ² ) was applied on both sides of this stainless steel foil, and heated and dried in an oven at 200°C to form the first anti-corrosion layer and the second anti-corrosion layer with the thicknesses shown in Table 1, respectively. Floor.

The water-soluble paint is 0.2% by mass of polyvinyl alcohol-containing non-crystalline polymer with hydroxyl, 0.8% by mass of FeCl ₂ ·4H ₂ O, 0.7% by mass of nitrilotris(methylene phosphonic acid) (commercial Name: CHELEST PH-320, produced by CHELEST Co., Ltd.)) is an aqueous solution in which water is dissolved.

After that, a first adhesive was applied on the formed first anticorrosion layer to form a first adhesive layer with a thickness of 3 μm. By melt-kneading 100 parts by mass of maleic anhydride-modified polypropylene (melting point 15° C.) and 7 parts by mass of epoxy novolac resin (manufactured by Mitsubishi Chemical Corporation, trade name: jER157S70) in toluene at room temperature for 10 minutes, Viscosity = 80, epoxy equivalent = 210) to obtain the first adhesive.

The first adhesive layer and the first base material layer made of a polypropylene resin film having a thickness of 6 μm in the laminate including this stainless steel foil were laminated at 120° C. by dry lamination.

In addition, by coating a urethane-based adhesive on the second substrate layer composed of a black stretched polyethylene terephthalate (PET) resin film with a thickness of 6-8 μm, (Main agent: TM-K55 (trade name, manufactured by Toyo Morton Co., Ltd.), curing agent: CAT-10L (trade name, manufactured by Toyo Morton Co., Ltd.)) was formed into a second adhesive layer (thickness 3 μm).

The second adhesive layer was opposed to the second anticorrosion layer in the above-obtained laminate, and laminated by dry lamination at 80° C. to obtain a laminate for battery exterior.

The surface defects of the obtained battery exterior laminate were visually observed, and evaluated under the following evaluation conditions. The results are shown in Table 1 as "plane defects".

A: No in-plane defect was observed per 1 m ² .

B: 1 to 5 in-plane defects were observed per 1 m ² .

C: 6 to 10 in-plane defects were observed per 1 m ² .

D: Eleven or more surface defects were observed per 1 m ² .

Prepare 3 g of electrolytic solution (1 mol/liter of LiPF ₆ added, ethylene carbonate: diethyl carbonate: dimethyl carbonate = 1:1:1 vol%), and fill it into three sides of the laminated body for battery exterior In a sealed bag (inner size 30mm×50mm, heat-sealing width 7mm). The three-side sealed bag was left to stand in a constant temperature bath at 85° C. for 2000 hours.

After 2000 hours, the three-side sealed bag was opened, and the presence or absence of peeling of the layer inside the metal foil was visually observed, and the following evaluation criteria were used for evaluation. The results are shown in Table 1 as "electrolyte solution resistance".

A: Peeling not confirmed

B: A little peeling is confirmed but within the allowable range

C: Acknowledgment to peel

D: completely stripped

Moreover, after immersing the test piece immersed in the said electrolytic solution in pure water for 10 hours, it took out from pure water, and the state was observed visually. The results of evaluation based on the following evaluation criteria are shown in Table 1 as "after immersion in water".

A: Peeling not confirmed

B: A little peeling is confirmed but within the allowable range

C: Acknowledgment to peel

D: completely stripped

A test piece was obtained by cutting out the battery exterior laminated body in a size of 200 mm×100 mm. The test piece was placed in a cold forming device with a size of 100mm×50mm, and embossing was carried out under the condition that the drawing depth was 6mm. Breakage in the molded drawn portion and generation of pin holes were observed visually or by an optical microscope. The same test was carried out 10 times, and the evaluation results according to the following evaluation criteria are shown in Table 1 as "moldability".

A: The molded stretched portion did not break and pinholes did not occur.

B: 1 to 3 samples out of 10 samples had slight breakage within the allowable range or pinholes in the molded stretched portion.

C: 1 to 5 samples out of 10 samples had a small amount of breakage or pinholes in the molded stretched portion.

D: There were 6 or more samples out of 10 samples in which large-scale breakage or pinholes occurred in the molded stretched portion.

(Embodiments 6-10)

Except for using the adhesive shown in Table 1 in the first adhesive forming the first adhesive layer, a laminated body for battery exterior was produced in the same manner as in Example 3, and the same process as in Example 1 was carried out. Same rating. The results are shown in Table 1.

(Example 11)

Except for changing the dry lamination of the first adhesive layer and the first base material layer at 120°C to thermal lamination at 200°C, a battery exterior laminate was produced in the same manner as in Example 3, and the same procedure was carried out. Same evaluation as Example 1. The results are shown in Table 1.

(Example 12)

A battery exterior laminate was produced in the same manner as in Example 3 except that the first base material layer was changed from a block PP film to a random PP film, and the same evaluation as in Example 1 was performed. The results are shown in Table 1.

(Examples 13-14)

A battery exterior laminate was produced in the same manner as in Example 3 except that the stainless steel foil having a thickness of 20 μm was changed to a stainless foil having a thickness shown in Table 1, and the same evaluation as in Example 1 was performed. The results are shown in Table 1.

(Example 15)

Except that the first and second anticorrosion layers were subjected to chromium fluoride plating treatment to obtain the first and second anticorrosion layers with a thickness of 250 μm, a laminated body for battery exterior was produced in the same manner as in Example 1, The same evaluation as in Example 1 was performed. The results are shown in Table 1.

(comparative example 1)

In addition to using aluminum foil with a thickness of 20 μm instead of stainless steel foil as the metal foil, and using only maleic anhydride modified polypropylene (melting point 80 ° C) and no novolak epoxy resin as the first adhesive Except for this, a battery exterior laminate was produced in the same manner as in Example 11, and the same evaluations as in Example 1 were performed. The results are shown in Table 1.

(comparative example 2)

In addition to using aluminum foil with a thickness of 20 μm instead of stainless steel foil as the metal foil, and using 0.8 mass% CrF ₃ 3H ₂ O instead of 0.8 mass% FeCl ₂ 4H ₂ O in the first and second anti-corrosion layers, with A battery exterior laminate was produced in the same manner as in Example 3, and the same evaluations as in Example 1 were performed. The results are shown in Table 1.

(comparative example 3)

Except using only maleic anhydride-modified polypropylene (melting point 80° C.) and no novolac epoxy resin as the first adhesive, a battery exterior was manufactured in the same manner as in Example 3. The laminate was evaluated in the same way as in Example 1. The results are shown in Table 1.

(comparative example 4)

A battery exterior laminate was produced in the same manner as in Example 1 except that the first anticorrosion layer and the second anticorrosion layer were not provided, and the same evaluations as in Example 1 were performed. The results are shown in Table 1.

(comparative example 5)

Except for using the adhesive shown in Table 1 in the first adhesive forming the first adhesive layer, a laminated body for battery exterior was produced in the same manner as in Example 3, and the same process as in Example 1 was carried out. Same rating. The results are shown in Table 1.

[Table 1]

In Table 1, each ellipsis has the following meanings respectively.

(bPP): block polypropylene

(rPP): random polypropylene

(Ad-NV1): Contains 100 parts by mass of maleic anhydride-modified polypropylene (melting point 80° C.), and 5 parts by mass of epoxy novolac resin (manufactured by Mitsubishi Chemical Corporation, trade name: jER154, epoxy equivalent=178) 15% solid content of toluene solution binder

(Ad-NV2): Toluene solution adhesive with a solid content of 15% containing 100 parts by mass of maleic anhydride-modified polypropylene (melting point 80°C) and 2 parts by mass of epoxy novolak resin jER154

(Ad-NV3): 15% toluene solution adhesive containing 100 parts by mass of maleic anhydride-modified polypropylene (melting point 80°C) and 7 parts by mass of epoxy novolak jER154

(Ad-NV4): Toluene solution adhesive with a solid content of 15% containing 100 parts by mass of maleic anhydride-modified polypropylene (melting point 80°C) and 10 parts by mass of epoxy novolac resin jER154

(Ad-NV5): 15% toluene solution adhesive containing 100 parts by mass of maleic anhydride-modified polypropylene (melting point 80°C) and 15 parts by mass of novolac epoxy resin jER154

(Ad-NV6): Adhesive containing 100 parts by mass of maleic anhydride-modified polypropylene (melting point 140°C) and 5 parts by mass of novolak epoxy resin jER154

(Ad-BPNV): Containing 100 parts by mass of maleic anhydride-modified polypropylene (melting point 80° C.), and 5 parts by mass of novolac epoxy resin with a bisphenol A structure (manufactured by Mitsubishi Chemical, trade name: jER157S70, viscosity =80; Epoxy equivalent = 210) toluene solution adhesive with a solid content of 15%

(Ad-PN): Solid containing 100 parts by mass of maleic anhydride-modified polypropylene (melting point: 80° C.) and 5 parts by mass of phenoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name: Epikote 1001, epoxy equivalent=450) 15% toluene solution adhesive

(Ad-PP): An adhesive containing 100 parts by mass of maleic anhydride-modified polypropylene (melting point 140°C)

(SUS): stainless steel foil

(AL): aluminum foil

From the results shown in Table 1, it can be seen that the battery exterior laminates of Examples 1 to 15 can suppress the occurrence of surface defects, reduce peeling even when they come into contact with electrolyte or water, and have good moldability. The battery exterior laminates of 1 to 5 have superior characteristics (processability, moldability, mechanical strength, chemical solution resistance, and water resistance) compared with those of the battery exterior laminates.

[Examples 16-24]

In the above-mentioned Example 3, using 0.8 mass % of the metal halides shown in Table 2 instead of 0.8 mass % of FeCl ₂ ·4H ₂ O in the first anticorrosion layer and the second anticorrosion layer, Examples 16 to 4H 2 O were carried out. 24 studies. The evaluation method and evaluation criteria are the same as in Example 1 and the like. The results are shown in Table 2.

[Table 2]

metal halide surface defect Electrolyte resistance after water immersion Formability Example 16 FeF₃ B A B A Example 17 MnF₃ B A B A Example 18 MnCl₂ B B B A Example 19 CrF₃ B A B A Example 20 CrCl₃ B B B A Example 21 ZrCl₃ B B B A Example 22 TiCl₄ B B B A Example 23 CaCl₂ B C C A Example 24 AlCl₄ B C C A

From the results shown in Table 2, it was confirmed that the effect of the present application was obtained even when various compounds were used as the metal halide compound.

Claims (6)

1. A battery exterior laminate comprising at least a first base material layer, a first adhesive layer, a first anticorrosion layer, a stainless steel foil, and a second base material layer in this order. , characterized in that, The first substrate layer is a layer made of polyolefin, The first adhesive layer is a layer composed of an adhesive containing 100 parts by mass of an acid-modified polyolefin resin (A) and 1 to 10 parts by mass of a compound (B) having a plurality of epoxy groups. The compound (B) having multiple epoxy groups is a novolac epoxy resin. 2. The battery exterior laminate according to claim 1, wherein the novolac epoxy resin has a bisphenol A structure. 3 . The battery exterior laminate according to claim 1 , wherein the stainless steel foil has a thickness of 10 to 30 μm. 4 . 4. The battery exterior laminate according to claim 1, wherein the first base material layer is homopolypropylene or block polypropylene. 5 . A battery exterior body comprising the battery exterior laminate according to claim 1 , wherein: It has an internal space for accommodating batteries, and the first base material layer side of the battery exterior laminate is the internal space side. 6 . A battery comprising the battery exterior body according to claim 5 .