JP6768364B2 - Battery exterior laminate, battery exterior and battery - Google Patents

Description

The present invention relates to a battery exterior laminate that is good as an exterior body such as a secondary battery or a capacitor, and a battery exterior body and a battery obtained by using the laminate.

Amid growing awareness of the environment, secondary batteries such as lithium-ion batteries and capacitors such as electric double layer capacitors are attracting attention as storage batteries for storing electrical energy as well as utilizing natural energy such as solar power and wind power. ing.
As the exterior body used for these batteries, a battery exterior laminate in which a metal foil and a resin layer are laminated is used for the purpose of miniaturization and weight reduction. Such a battery exterior laminate is formed by drawing or the like so as to form a tray having recesses to form an exterior container body.
Further, in the same manner as the outer body container main body, the battery outer laminate is molded to obtain the outer body lid portion. After storing the battery body in the recess of the exterior container body, the exterior body lid is overlapped so as to cover the stored battery body, and the side edges of the container body and the exterior body lid are adhered to form the exterior. You can get a battery in which the battery body is stored in the body.

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

Japanese Unexamined Patent Publication No. 2012-333393

As the application fields of batteries such as secondary batteries are expanding, the development of small batteries with large capacity is being promoted. Similarly, the laminate for battery exterior is also required to be thinned while maintaining excellent properties such as mechanical strength, water resistance, and chemical resistance (electrolyte resistance). In general, the mechanical strength, water resistance, chemical resistance (electrolyte resistance) and light-shielding property of the battery exterior laminate are mainly ensured by an inorganic layer such as a metal foil in the battery exterior laminate. ing. As the metal foil, an aluminum foil having excellent workability is widely used (see Patent Document 1).
However, since aluminum foil is superior in workability to other metal foils, it is possible to manufacture a laminate with a high yield, while mechanical strength such as piercing strength is higher than that of other metal foils. Is inferior. Therefore, in order to obtain mechanical strength, the thickness of the aluminum foil cannot be kept below a certain level, and in the present situation where the aluminum foil is used, it is difficult to make the thin film of the battery exterior laminate.

The present invention has been made in view of the above situation, and an object of the present invention is to provide a battery exterior laminate which can be thinned and has excellent various characteristics.

As a result of repeated studies to achieve the above object, the present inventors have adopted a configuration in which a thin film can be formed while ensuring mechanical strength such as piercing strength by using stainless steel foil instead of aluminum foil. .. However, it has been found that when a laminated body for battery exterior is manufactured using stainless steel foil, there are problems such as surface defects which are considered to be due to poor adhesion which are not seen in conventional aluminum steel foil, and electrolyte resistance. Therefore, the present inventors have made extensive studies and succeeded in finding a new adhesive capable of suitably adhering the stainless steel foil surface-treated with a corrosion inhibitor and the base material layer. The present invention has been completed.

That is, the present invention has adopted the following configuration.
A first aspect of the present invention is a laminate for battery exterior, which comprises at least a first base material layer, a first adhesive layer, a first corrosion prevention layer, a stainless steel foil, and a second base material layer in this order. The first base material layer is a layer made of polyolefin, and the first adhesive layer is a compound containing 100 parts by mass of an acid-modified polyolefin resin (A) and a plurality of epoxy groups. B) A laminate for battery exterior, which is a layer made of an adhesive containing 1 to 20 parts by mass.
The compound containing the plurality of epoxy groups is preferably a phenol novolac type epoxy resin.
The epoxy equivalent of the phenol novolac type epoxy resin is preferably 100 to 300.
The phenol novolac type epoxy resin preferably has a bisphenol A structure.
The first corrosion prevention 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 corrosion prevention layer preferably contains a resin having a polyvinyl alcohol skeleton, a metal fluoride compound, and a phosphoric acid compound.
The thickness of the stainless steel foil is preferably 10 to 30 μm.
The first base material layer is preferably homopolypropylene or block polypropylene.
A second aspect of the present invention is a battery exterior body including the battery exterior laminate of the first aspect, which has an internal space for accommodating a battery and is a first base material layer of the battery exterior laminate. The battery exterior is characterized in that the side of the battery is the side of the internal space.
A third aspect of the present invention is a battery comprising the battery exterior body of the second aspect.

According to the present invention, it is possible to provide a battery exterior laminate having excellent characteristics and capable of being manufactured with high yield and productivity. Further, the battery exterior laminate of the present invention can be thinned.

It is schematic cross-sectional view which shows 1st Embodiment of the laminated body for battery exterior which concerns on this invention. It is a perspective view which shows an example of the secondary battery produced using the battery exterior laminated body which concerns on this invention. It is a perspective view which shows the process of manufacturing a secondary battery using the battery exterior laminated body which concerns on this invention. It is a perspective view which shows the process of manufacturing a secondary battery using the battery exterior laminated body which concerns on this invention.

Hereinafter, the present invention will be described based on preferred embodiments. It should be noted that the present embodiment describes the gist of the invention more specifically, but does not limit the present invention unless otherwise specified.

[Battery exterior laminate]
The battery exterior laminate (hereinafter, may be simply referred to as “laminate”) according to the first aspect of the present invention is at least a first base material layer, a first adhesive layer, a first corrosion prevention layer, and stainless steel. A laminate for battery exterior provided with a steel foil and a second base material layer in this order.
The first base material 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 20 parts by mass of a compound (B) containing a plurality of epoxy groups. ..

FIG. 1 is a cross-sectional view showing a schematic configuration of a battery exterior laminate 10 according to an embodiment of the present invention.
The laminate 10 according to the present embodiment includes a first base material layer 11, a first adhesive layer 12, a first corrosion prevention layer 13, a stainless steel foil 14, a second corrosion prevention layer 16, and a second. The adhesive layer 17 and the second base material layer 15 are provided in this order.
That is, the laminate 10 according to the present embodiment has the first corrosion prevention layer 13 and the second corrosion prevention layer 16 formed on both surfaces of the stainless steel foil 14, and the first adhesive layer on the first corrosion prevention layer 13. It has a seven-layer structure including a first base material layer 11 laminated via 12 and a second base material layer 15 laminated on a second corrosion prevention layer 16 via a second adhesive layer 17. ..
Hereinafter, each layer will be described in detail.

The first base material layer 11 is a layer made of polyolefin. Examples of the layer made of polyolefin include polyethylene, polypropylene, poly-1-butene, polyisobutylene, a random copolymer of propylene and ethylene or α-olefin, and a block copolymer of propylene and ethylene or α-olefin. ..
Among them, since the adhesiveness with the first adhesive layer 12 is improved, homopolypropylene (propylene homopolymer; hereinafter, may be referred to as “homoPP”) and propylene-ethylene block copolymer (hereinafter, referred to as “homoPP”). , "Block PP"), a polypropylene-ethylene random copolymer (hereinafter, may be referred to as "random PP") or the like, polypropylene-based resins are preferable. Among them, homo PP or block PP is more preferable, and block PP is particularly preferable because it has excellent mechanical strength.
The first base material layer 11 may have a single-layer structure or a multi-layer structure.

The melting point of the layer made of polyolefin used for the first base material layer 11 is not particularly limited as long as it has the heat resistance required for the battery exterior laminate 10.
The thickness of the first base material layer 11 can be, for example, 1 to 30 μm.

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

As described above, the battery exterior laminate is required to have various properties such as mechanical strength, water resistance, and chemical resistance (electrolyte resistance). Many of these characteristics are borne by the metal foil in the battery exterior laminate, and the metal foil in the battery exterior plays a very important role from the viewpoint of battery durability. Then, a metal foil that has been subjected to a rust preventive treatment is usually used so that the metal foil does not deteriorate due to rust or the like when the battery is used.
The composition of a corrosion inhibitor (corrosion preventive layer) having a good corrosion preventive effect is widely known for the conventionally used aluminum foil.
On the other hand, in the present invention, a stainless steel foil is used in order to achieve both thinning and mechanical strength (piercing strength, etc.). It is known that stainless steel is less likely to rust in metals, but stainless steel foil of battery exterior laminates used under extreme conditions such as being able to come into contact with electrolytes is treated with rust prevention as in the past. Is preferably performed. Then, the rust preventive treatment agent that can satisfactorily impart the rust preventive effect to the stainless steel foil and the conventional rust preventive treatment agent for aluminum foil may have different compositions.

However, as a result of providing the first corrosion prevention layer made of such a rust preventive treatment agent for stainless steel foil on the surface of the stainless steel foil, the conventional adhesive has the surface of the first corrosion prevention layer and the surface of the first base material layer. It was found that the and could not be adhered well, and surface defects due to poor adhesion could occur.
Therefore, the present inventors further studied, and as an adhesive capable of satisfactorily adhering the rust preventive layer (first corrosion preventive layer) for stainless steel foil and the first base material layer, the acid-modified polyolefin resin (A). We have found an adhesive containing 100 parts by mass of the above and (B) 1 to 20 parts by mass of a compound containing a plurality of epoxy groups.
Then, by using the first base material layer, the first adhesive layer made of such an adhesive, the first corrosion prevention layer, and the stainless steel foil, (1) the mechanical strength of the stainless steel foil. Improvement of (piercing strength, etc.) and realization of thinning, (2) Anti-corrosion effect of stainless steel foil by the first corrosion prevention layer and improvement of durability by it, (3) Machine by the first adhesive layer It is possible to improve the target strength (peeling strength, etc.), reduce the occurrence of surface defects due to poor adhesion during the production of the laminate, and improve the yield.

-Adhesive In the present invention, the adhesive forming the first adhesive layer 12 is 100 parts by mass of the acid-modified polyolefin resin (A) and 1 to 20 parts by mass of the compound containing a plurality of epoxy groups (B). , Is contained.
Hereinafter, the acid-modified polyolefin resin (A) may be referred to as “component (A)”, and the compound (B) containing a plurality of epoxy groups may be referred to as “component (B)”.

(Acid-modified polyolefin resin (A))
In the present invention, the acid-modified polyolefin resin (A) is a polyolefin-based resin modified with an unsaturated carboxylic acid or a derivative thereof, and an acid-functional group such as a carboxy group or an anhydrous carboxylic acid group is contained in the polyolefin-based resin. It has.
The component (A) is obtained by modifying a polyolefin resin with an unsaturated carboxylic acid or a derivative thereof, copolymerizing an acid functional group-containing monomer with olefins, or the like. Among them, the component (A) is preferably obtained by acid-modifying a polyolefin resin.
Examples of the acid modification method include graft modification in which a polyolefin resin and an acid functional group-containing monomer are melt-kneaded in the presence of a radical polymerization initiator such as an organic peroxide or an aliphatic azo compound.

Examples of the polyolefin-based resin include polyethylene, polypropylene, poly-1-butene, polyisobutylene, a random copolymer of propylene and ethylene or α-olefin, and a block copolymer of propylene and ethylene or α-olefin. Be done. Among them, homopolypropylene (propylene homopolymer; hereinafter, sometimes referred to as “homo PP”), propylene-ethylene block copolymer (hereinafter, sometimes referred to as “block PP”), propylene-ethylene. Polypropylene-based resins such as Random Copolymer (hereinafter, may be referred to as "Random PP") are preferable, and Random PP is particularly preferable.
Examples of the olefins in the case of copolymerization include olefin-based 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 and a carboxy group or a carboxylic acid anhydride group in the same molecule, and is an acid of various unsaturated monocarboxylic acids, dicarboxylic acids, or dicarboxylic acids. An anhydride is mentioned.
Examples of the acid functional group-containing monomer having a carboxy group (carboxy group-containing monomer) include acrylic acid, methacrylic acid, maleic acid, nadic acid, fumaric acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, tetrahydrophthalic acid, and endo. Examples thereof include α, β-unsaturated carboxylic acid monomers such as −bicyclo [2.2.1] -5-heptene-2,3-dicarboxylic acid (endic acid).
Examples of the acid functional group-containing monomer having a carboxylic acid anhydride group (carboxylic acid anhydride group-containing monomer) include unsaturated dicarboxylic acids such as maleic anhydride, nadicic anhydride, itaconic anhydride, citraconic anhydride, and endic anhydride. Anhydride monomer can be mentioned.
As these acid functional group-containing monomers, one type may be used alone in the component (A), or two or more types may be used in combination.

Among them, as the acid functional group-containing monomer, an acid functional group-containing monomer having an acid anhydride group is preferable, and a carboxylic acid anhydride group-containing monomer is more preferable, and anhydrous because it has high reactivity with the component (B) described later. Maleic acid is particularly preferred.
When a part of the acid functional group-containing monomer used for acid modification was unreacted, the unreacted acid functional group-containing monomer was removed in advance in order to prevent the adhesive strength from being lowered by the unreacted acid functional group-containing monomer. It is preferable to use the one as the component (A).

In the component (A), the component derived from the polyolefin resin or the olefins is preferably 50 parts by mass or more with respect to 100 parts by mass of the total amount of the component (A).

The melting point of the component (A) is not particularly limited.
For example, if the adhesive used in the present invention does not contain an organic solvent and the component (A) and the component (B) described later are melt-kneaded to form an adhesive, the melting point of the component (A) is The temperature is preferably 100 ° C to 180 ° C. The adhesive layer made of such an adhesive can be suitably used as an adhesive layer for thermal laminating.
By using the component (A) having a melting point in the above range, the component (A) and the component (B) described later can be separated from the melting point of the component (A) even when a conventional method or a general apparatus is used. Can be melt-kneaded at a sufficiently high temperature. Further, when the component (A) and the component (B) described later are reacted by using melt kneading, the melting point of the component (B) is preferably lower than that of the component (A), but the melting point in the above range is set. By using the component (A) having the component (A), the degree of freedom in selecting the component (B) can be increased.
Further, as described above, the melting point of the component (A) is preferably higher than the melting point of the component (B) described later, but the melting point of the component (A) is 10 ° C. or more higher than the melting point of the component (B). Is more preferable, 20 ° C. or higher is further preferable, and 30 ° C. or higher is particularly preferable. Since the melting point of the component (A) is sufficiently higher than that of the component (B), the component (B) is melted first when melt-kneading is performed, and the component (A) retains the shape of the resin. As a result of permeation and uniform reaction of the component (A) and the component (B), good durability can be obtained.

On the other hand, when the first adhesive layer 12 is used as the adhesive layer for dry lamination, the melting point of the component (A) is preferably 50 to 100 ° C. By providing a layer made of an adhesive containing polyolefin having a relatively low melting point of 50 to 100 ° C., the stainless steel foil is provided at a relatively low temperature such that distortion does not occur, that is, at a temperature of around 100 ° C. or lower. , The stainless steel foil having the first corrosion prevention layer and the first base material layer can be adhered to each other via the first adhesive layer.

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

(Compound (B) containing a plurality of epoxy groups)
The component (B) is a compound containing a plurality of epoxy groups. The component (B) may be a low molecular weight compound or a high molecular weight compound. From the viewpoint of improving miscibility with the component (A), the component (B) is preferably a polymer compound (resin). On the other hand, from the viewpoint of improving the solubility in a solvent, the component (B) is preferably a low molecular weight compound.

The structure of the component (B) is not particularly limited as long as it has a plurality of epoxy groups, and examples thereof include a phenoxy resin synthesized from bisphenols and epichlorohydrin; a phenol novolac type epoxy resin; and a bisphenol type epoxy resin. Among them, it is preferable to use a phenol novolac type epoxy resin because the epoxy content per molecule is high and a particularly dense crosslinked structure can be formed together with the component (A).

In the present invention, the phenol novolac type epoxy resin is a compound having a basic structure of a phenol novolac resin obtained by acid condensation of phenol and formaldehyde, and an epoxy group introduced into a part of the structure. The amount of epoxy group introduced per molecule in the phenol novolac type epoxy resin is not particularly limited, but by reacting an epoxy group raw material such as epichlorohydrin with the phenol novolac resin, a large number of phenols present in the phenol novolac resin are present. Since a large number of epoxy groups are introduced into the phenolic hydroxyl group, it is usually a polyfunctional epoxy resin.

Among them, as the phenol novolac type epoxy resin, a bisphenol A novolac type epoxy resin having a phenol novolac structure as a basic skeleton and also having a bisphenol A structure is preferable. The bisphenol A structure in the phenol novolac type epoxy resin may be any structure as long as it can be derived from bisphenol A, and the hydroxyl groups at both ends of the bisphenol A may be substituted with a group such as an epoxy group-containing group.
An example of the bisphenol A novolak type epoxy resin is a resin represented by the following general formula (1).

［式（１）中、Ｒ^１〜Ｒ^６はそれぞれ独立に水素原子又はメチル基であり、ｎは０〜１０の整数であり、Ｒ^Ｘはエポキシ基を有する基である。］

In Expression ^(1), R 1 ~R ⁶ are each independently a hydrogen atom or a methyl group, n is an integer of 0, ^{R X} is a group having an epoxy group. ]

In formula (1), R ^{1 to} R ⁶ are independently hydrogen atoms or methyl groups, respectively. When n is an integer of 2 or more, R ³ and R ⁴ may be the same or different, respectively.
The resin represented by the formula (1) preferably satisfies at least one of the following (i) to (iii).
(I) Both R ¹ and R ² are methyl groups, (ii) both R ³ and R ⁴ are methyl groups, and both (iii) R ⁵ and R ⁶ are methyl groups, for example, satisfying (i) above. Therefore, in the 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 form a structure derived from bisphenol A.

In formula (1), ^RX is a group having an epoxy group. Examples of the group having an epoxy group include an epoxy group and a combination of an epoxy group and an alkylene group, and a glycidyl group is preferable.

The epoxy equivalent of the bisphenol A novolak type epoxy resin is preferably 100 to 300, and more preferably 200 to 300. The epoxy equivalent (g / eq) is the molecular weight of the epoxy resin per epoxy group, and the smaller this value is, the more epoxy groups are in the resin. By using a phenol novolac type epoxy resin having a relatively small epoxy equivalent, the adhesiveness between the phenol novolac type epoxy resin and the adherend becomes good even when the amount of the phenol novolac type epoxy resin added is relatively small. Moreover, the phenol novolac type epoxy resin and the component (A) are sufficiently crosslinked.

Examples of such bisphenol A novolak type epoxy resin include jER154, jER157S70, and jER-157S65 manufactured by Mitsubishi Chemical Corporation; EPICLON manufactured by DIC Corporation.
Commercially available products such as N-730A, EPICLON N-740, EPICLON N-770, and EPICLON N-775 (all of which are trade names) can also be used.

By using the epoxy resin as described above, both the acid functional group of the component (A) and the epoxy group of the component (B) with respect to the adherend (particularly the functional group such as the hydroxyl group possessed by the adherend). It is considered that by functioning as an adhesive functional group, it is possible to exhibit excellent adhesiveness to the first base material layer 11 and the first corrosion prevention layer 13.
Further, a part of the acid functional group of the component (A) reacts with a part of the epoxy group of the component (B) to form a crosslinked structure of the component (A) and the component (B), and this crosslinked structure forms a resin. It is considered that the strength of the epoxy is reinforced and good durability is obtained as well as excellent adhesiveness.

In the adhesive used in the present invention, the component (B) is contained in an amount of 1 to 20 parts by mass with respect to 100 parts by mass of the component (A). More preferably, the component (B) is 5 to 10 parts by mass with respect to 100 parts by mass of the component (A), and most preferably the component (B) is 5 to 7 parts by mass with respect to 100 parts by mass of the component (A). It is a department.
The adhesive used in the present invention can appropriately contain a miscible additive, an additional resin, a plasticizer, a stabilizer, a colorant and the like, if desired.

Further, the adhesive of the present invention may or may not contain an organic solvent.
By containing an organic solvent to prepare a liquid adhesive, for example, an adhesive suitable for dry lamination can be obtained. An adhesive layer can be formed by applying and drying such a liquid adhesive on a lower layer.
On the other hand, when the organic solvent is not contained, an adhesive layer suitable for thermal lamination or the like can be formed by melt-kneading the acid-modified polyolefin resin and the epoxy resin and then extruding or the like.
When an organic solvent is contained, the organic solvent used is not particularly limited as long as it can suitably dissolve the above-mentioned resin, and for example, toluene or the like can be used. The amount of the organic solvent used is not particularly limited, but the solid content is preferably 3 to 30% by mass, more preferably 5 to 25% by mass, still more preferably 10 to 20% by 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 adhered with a high adhesive force, and delamination can be prevented.

In this embodiment, the first corrosion prevention layer 13 is a layer for preventing corrosion of the stainless steel foil 14 due to rust or the like.
The first corrosion prevention layer 13 preferably contains a metal halide compound, and the surface of the stainless steel foil 14 may be directly plated with the metal halide compound as described later.
By providing such a first corrosion prevention layer 13, it is possible to satisfactorily impart a rust prevention effect to the stainless steel foil.
Among them, the first corrosion prevention layer 13 preferably further contains a water-soluble resin, and after applying a water-soluble paint containing a water-soluble resin, a metal halide, and a chelating agent, it is dried and cured. It is preferably formed by allowing.

・ Water-soluble paint (water-soluble resin)
As the water-soluble resin, it is preferable to use one or more of a polyvinyl alcohol-based resin and a polyvinyl ether-based resin.
The polyvinyl alcohol-based resin is at least one water-soluble resin selected from a polyvinyl alcohol resin and a modified polyvinyl alcohol resin.
The polyvinyl alcohol-based resin can be produced, for example, by saponifying a polymer of a vinyl ester-based monomer or a copolymer thereof.
As the polymer of the vinyl ester-based monomer or its copolymer, a homopolymer of a fatty acid vinyl ester such as vinyl formate, vinyl acetate, vinyl butyrate, or a homopolymer of a vinyl ester-based monomer such as an aromatic vinyl ester such as vinyl benzoate, or Examples thereof include a copolymer and a copolymer of another monomer copolymerizable therewith.
Other copolymerizable monomers include, for example, olefins such as ethylene and propylene, ether group-containing monomers such as alkyl vinyl ether, carbonyl groups such as diacetone acrylamide, diacetone (meth) acrylate, allyl acetoacetate, and acetoacetate ester. Examples thereof include (ketone group) -containing monomers, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and maleic anhydride, vinyl halides such as vinyl chloride and 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 the polyvinyl alcohol-based resin include alkyl ether-modified polyvinyl alcohol resin, carbonyl-modified polyvinyl alcohol resin, acetoacetyl-modified polyvinyl alcohol resin, acetoamide-modified polyvinyl alcohol resin, acrylic nitrile-modified polyvinyl alcohol resin, carboxyl-modified polyvinyl alcohol resin, and silicone-modified polyvinyl alcohol. Examples thereof include resins and ethylene-modified polyvinyl alcohol resins. Among them, alkyl ether-modified polyvinyl alcohol resin, carbonyl-modified polyvinyl alcohol resin, carboxyl-modified polyvinyl alcohol resin, and acetoacetyl-modified polyvinyl alcohol resin are preferable.
Commercially available polyvinyl alcohol-based resins include, for example, J-Poval DF-20 (trade name) manufactured by Japan Vam & Poval Co., Ltd. and Crosmer H series manufactured by Nippon Carbide Industries Co., Ltd. ( Product name) and so on. As the polyvinyl alcohol-based resin, one kind or a mixture of two or more kinds may be used.

Examples of the polyvinyl ether-based resin include ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, norbornyl vinyl ether, allyl vinyl ether, norbornenyl vinyl ether and 2-hydroxy. Examples thereof include homopolymers or copolymers of aliphatic vinyl ethers such as ethyl vinyl ether and diethylene glycol monovinyl ether, and copolymers of other monomers copolymerizable therewith. Examples of the other monomer copolymerizable with the vinyl ether-based monomer include those similar to the other monomers copolymerizable with the vinyl ester-based monomer described above.
In particular, polyvinyl ether-based resins containing an aliphatic vinyl ether having a hydroxyl group as a monomer, such as 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 2-hydroxypropyl vinyl ether, and monovinyl ethers of various glycols and polyhydric alcohols, are water-soluble. It can be suitably used in the present invention because it has a cross-linking reaction with respect to a hydroxyl group.
Since the vinyl ether monomer can be used in the resin production (polymerization) step, these polyvinyl ether-based resins undergo a saponification treatment unlike the polyvinyl alcohol-based resins produced via the vinyl ester-based polymer. It can be manufactured without any. Further, a copolymer containing a vinyl ester-based monomer and a vinyl ether-based monomer, or a vinyl alcohol-vinyl ether copolymer obtained by saponifying the copolymer can also be used. A mixture of a polyvinyl alcohol-based resin other than the polyvinyl ether-based resin and a polyvinyl ether-based resin can also be used.

As the water-soluble resin, only one of the polyvinyl alcohol-based resin and the 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 above-mentioned water-soluble resin.
Examples of the metal halide compound include chromium halide, iron halide, zirconium halide, titanium halide, hafnium halide, hydrohydrogenate titanium halide, and salts thereof. Examples of the halogen atom include chlorine, bromine and fluorine, and chlorine or fluorine is preferable. Further, fluorine is particularly preferable.
Among them, as the metal halide compound, chlorides or fluorides of iron, chromium, manganese or zirconium are preferable.
The metal halide compound has an action of improving chemical resistance such as electrolytic solution resistance. That is, the surface of the stainless steel foil 14 can be passivated and the corrosion resistance to the electrolytic solution can be improved. The metal halide compound also has an action of cross-linking the water-soluble resin.

(Chelating agent)
Water-soluble paints contain chelating agents. The chelating agent is a material that can coordinate-bond to metal ions to form a metal ion complex.
The chelating agent binds a metal compound (chromium oxide or the like) derived from the metal halide compound to the water-soluble resin to increase the compressive strength of the first corrosion prevention layer 13, so that the first corrosion prevention layer 13 has a chelating agent. Even when the thickness exceeds, for example, 0.2 μm and is 1.0 μm or less, the first corrosion prevention layer 13 does not become brittle and crack or peel 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 thereof can be increased.
Further, the chelating agent has an action 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, an aminocarboxylic acid-based chelating agent, a phosphonic acid-based chelating agent, an oxycarboxylic acid-based chelating agent, and a (poly) phosphoric acid-based chelating agent can be used.

Examples of the aminocarboxylic acid-based chelating agent include nitrilotriacetic acid (NTA), hydroxyethyliminodiacetic acid (HIDA), ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), diethylenetriaminetetraacetic acid (DTPA), and the like. Triethylenetetraminetetraacetic acid (TTHA), transcyclohexanediaminetetraacetic acid (CyDTA), 1,2-propanediaminetetraacetic acid (1,2-PDTA), 1,3-propanediaminetetraacetic acid (1,3-PDTA), 1,4-Butandiaminetetraacetic acid (1,4-BDTA), 1,3-diamino-2-hydroxypropanetetraacetic acid (DPTA-OH), glycol etherdiaminetetraacetic acid (GEDTA), ethylenediamine orthohydroxyphenylacetic acid (EDHPA) ), SS-Ethylenediaminediaminediaminedic acid (SS-EDDS), ethylenediaminediaminediaminedicic acid (EDDS), β-alanine diacetic acid (ADA), methylglycine diacetic acid (MGDA), L-aspartic acid-N, N-diacetate. (ASDA), L-glutamic acid-N, N-diacetic acid (GLDA), N, N'-bis (2-hydroxybenzyl) ethylenediamine-N, N'-diacetic acid (HBEDDA) can be mentioned.

The phosphonic acid-based 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 is, for example, N. , N, N-trimethylenphosphonic acid (NTMP), 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), ethylenediamine-N, N, N', N'-tetramethylenephosphonic acid (EDTMP), diethylenetriaminepenta Methylenephosphonic acid (DTPMP), 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC), nitrilotris (methylenephosphonic acid) (NTMP), and the like.

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

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

Commercially available chelating agents include, for example, aminocarboxylic acid chelating agents such as Kirest PD-4H (PDTA); Kirest PH-540 (EDTMP), Kirest PH-210 (HEDP), Kirest PH-320. (NTMP), phosphonic acid-based chelating agents such as Kirest PH-430 (PBTC) (all of which are chelating agents manufactured by Kirest Co., Ltd., and the notation is a trade name) can be mentioned.

Among them, as the chelating agent, a phosphoric acid-based chelating agent (phosphoric acid compound) such as a phosphonic acid-based chelating agent and a (poly) phosphoric acid-based chelating agent is preferable, and a phosphonic acid-based chelating agent is more preferable.

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

The water-soluble coating material can be produced by dissolving a water-soluble resin, a metal halide compound, and a chelating agent in a solvent containing water. Water is preferable as the solvent.
The solid content concentration in the water-soluble paint can be appropriately determined in consideration of the coatability of the first corrosion prevention layer 13 and the like, but is generally 0.1 to 10% by mass.

The thickness of the first corrosion prevention layer 13 is preferably 0.05 μm or more, more preferably more than 0.1 μm. By setting the thickness of the first corrosion prevention layer 13 to 0.05 μm or more, sufficient corrosion resistance is given to the battery exterior laminate 10, and the adhesive strength between the stainless steel foil 14 and the first adhesive layer 12 is provided. , And the adhesive strength between the stainless steel foil 14 and the first base material layer 11 can be increased.
The thickness of the first corrosion prevention layer 13 is preferably 1.0 μm or less, more preferably 0.5 μm or less. By setting the thickness of the first corrosion prevention layer 13 to 1.0 μm or less, the adhesive strength between the stainless steel foil 14 and the first adhesive layer 12 can be increased, 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, stainless steel such as austenite, ferritic, and martensitic. The austenitic stainless steel includes SUS304, 316, 301 and the like, the ferrite type includes SUS430 and the like, and the martensitic stainless steel includes SUS410 and the like.

Since the stainless steel foil 14 has higher mechanical strength such as piercing strength and tensile strength than other metal foils such as aluminum foil, it can be used as a laminate 10 for battery exterior even when used with a thickness of 40 μm or less. Sufficient mechanical strength can be imparted. As a result, the stainless steel foil 14 and the laminate 10 as a whole can be thinned.
Further, due to the high mechanical strength, it is possible to reduce the occurrence of pinholes when forming recesses by drawing molding, and as a result, leakage of the contents sealed by the laminate (for example, leakage of battery liquid). Can be reduced. In addition, since the stainless steel foil 14 is superior in corrosion resistance to other metal foils, it is possible to satisfactorily prevent deterioration due to corrosion.

The thickness of the stainless steel foil 14 is preferably 100 μm or less, preferably 5 to 40 μm, more preferably 10 to 30 μm, and particularly preferably 10 to 20 μm. By setting the value to the above lower limit or more, sufficient mechanical strength can be given to the battery exterior laminate 10 and the durability of the battery can be enhanced when used for a battery such as a secondary battery. Further, by setting the thickness of the stainless steel foil 14 to be equal to or less than the above upper limit value, the battery exterior laminate 10 can be made sufficiently thin and sufficient drawing workability can be provided.

The second corrosion prevention layer 16 has the same structure as the first corrosion prevention 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-based adhesive or an epoxy-based adhesive. The thickness of the second adhesive layer 17 can be, for example, 0.5 to 10 μm. By setting the thickness within this range, the second base material layer 15 and the stainless steel foil 14 can be adhered with a 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, and is, for example, a polyester resin such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT); A polyamide resin such as nylon (Ny); a polyolefin resin such as stretched polypropylene (OPP); a synthetic resin film made of polyetheretherketone (PEEK), polyphenylene sulfide (PPS), or the like can be used. Of these, PET film is preferable.
The thickness of the second base material layer 15 can be, for example, 1 to 50 μm, preferably 1 to 30 μm, and even more preferably 3 to 11 μm.

The second base material layer 15 may have a single-layer structure or a multi-layer structure. As an example of the second base material layer 15 having a multilayer structure, a bilayer film in which a polyethylene terephthalate (PET) resin film is laminated on a biaxially stretched polyamide resin film (ONy) can be mentioned. The second base material layer 15 may have a multilayer structure in which three or more films are laminated.
Further, in the embodiment shown in FIG. 1, the second base material layer 15 is the outermost layer. Therefore, the second base material layer may have a desired color and design by containing a colorant such as a pigment in addition to the resin.

The second base material layer 15 is preferably made of 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 a heat-resistant resin film include PET film, PEN film, PBT film, nylon film, PEEK film, PPS film and the like, and PET film which is advantageous in terms of cost is particularly preferable. By using such a heat-resistant resin film, the heat resistance of the battery exterior laminate 10 can be enhanced, and the durability of the battery in which the battery exterior laminate 10 is used can be improved.

In the battery exterior laminate 10 shown in FIG. 1, the first corrosion prevention layer 13 and the second corrosion prevention layer 16 are formed on both sides of the stainless steel foil 14, but the battery using the battery exterior laminate 10 is used. In the outer body, it is the inner surface side, and it is the first base material layer 11 side that can come into contact with the electrolytic solution or the like. Therefore, the corrosion prevention layer may be formed at least on the first base material layer 11 side of the stainless steel foil 14. That is, it is also possible to omit the second corrosion prevention layer 16 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 can also be formed on the outer surface side of the second base material layer 15.
The coating layer (first coating layer) is 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. , Cellulosic ester resin, cellulose ether resin, polyamide resin, polyvinylidene ether resin (PPE), polyvinylidene sulfide resin (PPS), polyarylether resin (PAE), polyetheretherketone resin (PEEK). It is made of at least one resin. The coating layer is preferably made of a material having excellent 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 applying and drying a solvent-based paint prepared by dissolving the resin in a general organic solvent.
By forming the coating layer, the insulating property of the battery exterior laminate 10 can be enhanced, and the surface of the battery exterior laminate 10 can be prevented from being scratched. Further, even when the battery exterior laminate 10 comes into contact with the electrolytic solution, it is possible to prevent a change in appearance (discoloration or the like).
Further, the coating layer can be colored by adding a colorant or a pigment to the solvent-based paint that forms the coating layer. In addition, the coating layer can be colored or printed so as to display characters, figures, images, patterns, etc. to enhance the design.
The thickness of the coating layer can be, 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 in direct contact with each other, but in order to enhance the design on the inner surface side of the second base material layer 15. It is also possible to provide a printing layer of.
The print layer can have the same structure 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 in which the battery exterior laminate 10 is used include those using an organic electrolyte as the electrolytic solution, such as a secondary battery such as a lithium ion battery which is a secondary battery, and a capacitor such as an electric double layer capacitor. .. The organic electrolyte is generally one in which carbonate esters such as propylene carbonate (PC), diethyl carbonate (DEC), and ethylene carbonate are used as a medium, but the organic electrolyte is not particularly limited thereto.

In the battery exterior laminate of the present invention, for example, a step of forming a first corrosion prevention layer on one side of a stainless steel foil, a step of forming a first adhesive layer on the formed first corrosion prevention layer, and a step of forming a first adhesive layer. , The first base material layer and the formed first adhesive layer are arranged so as to be in contact with each other, and the laminated body can be laminated.
The details will be described below.

First, the first corrosion prevention layer 13 is formed on one side of the stainless steel foil 14.
Specifically, the water-soluble paint as described above is applied to the surface of the stainless steel foil 14, and then heat-dried. At this time, only the first corrosion prevention layer 13 may be formed by applying the water-soluble paint to only one side of the stainless steel foil 14, or by applying the water-soluble paint to both sides of the stainless steel foil 14. The second corrosion prevention layer 16 may be formed at the same time. When the second corrosion prevention layer 16 is provided, the second corrosion prevention layer 16 is preferably formed at a stage before the formation of the first adhesive layer 12 and the like, and at the same time as the first corrosion prevention layer 13. It is more preferable to be formed.
When the first corrosion prevention layer 13 and the second corrosion prevention layer 16 are formed at the same time, the stainless steel foil 14 is immersed in a water-soluble paint to adhere the water-soluble paint to both sides of the stainless steel foil 14, and then. It is also preferable to heat-dry.

Next, the first adhesive layer 12 is formed on the first corrosion prevention layer 13.
Specifically, a layer made of the adhesive as described above is formed on the surface of the stainless steel foil 14 provided with the first corrosion prevention layer 13, and if necessary, it is heated and dried.

When the adhesive is a thermal laminating adhesive that does not contain an organic solvent, the components (A) and (B) are melt-kneaded to react both components, and then on the first corrosion prevention layer 13. The first adhesive layer 12 is formed by applying and drying.
For melt kneading, known devices such as a uniaxial extruder, a multi-screw extruder, a Banbury mixer, a plast mill, and a heating roll kneader can be used. In order to suppress the decomposition of epoxy groups during melt-kneading, volatile components that can react with epoxy groups such as moisture should be removed from the device in advance, and if volatile components are generated during the reaction, degassing. It is desirable to discharge it to the outside of the device at any time. When the acid-modified polyolefin resin has an acid anhydride group as an acid functional group, it is preferable because the reactivity with the epoxy group is high and the reaction can be performed under more mild conditions. The heating temperature during melt-kneading is preferably selected from the range of 240 to 300 ° C. in that both components are sufficiently melted and do not thermally decompose. 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 after being extruded from the melt-kneading apparatus.

When the adhesive is a dry laminating adhesive containing an organic solvent, the component (A) and the component (B) are dissolved in the organic solvent, and then this solution is applied onto the first corrosion prevention layer 13. The first adhesive layer 12 is formed by applying and drying. Further, the formation of the first adhesive layer 12 may be performed as a series of steps using a known dry laminator or the like together with the laminating step with the first base material layer 11 described later.

After that, the first base material layer 11 and the formed first adhesive layer 12 are arranged so as to be in contact with each other, and the laminate is laminated. The laminate is preferably a dry laminate at 70 to 150 ° C. The pressure at the time of dry lamination is preferably 0.1 to 0.5 MPa.
Specifically, a film constituting the first base material layer 11 is prepared in advance, the film is arranged on the first adhesive layer, and then dry lamination is performed. The temperature of the dry laminate is not particularly limited as long as it is a temperature at which the first base material layer 11, the first corrosion prevention layer 13, and the stainless steel foil 14 are satisfactorily adhered to each other via the first adhesive layer. However, it can be determined in consideration of the material and melting point of the adhesive constituting the first adhesive layer 12. The temperature at the time of dry laminating is generally 70 to 150 ° C, preferably 80 to 120 ° C.

Since the battery exterior laminate of this embodiment has a structure in which the first base material layer 11, the first corrosion prevention layer 13, and the stainless steel foil 14 are bonded via the first adhesive layer 12, the above-mentioned is described at the time of bonding. It is possible to adopt a dry laminate such as. Then, by adopting a dry laminate instead of the thermal laminate, which requires heating of more than 200 ° C. at the time of laminating, the temperature at the time of laminating can be significantly reduced.
Generally, when high heat is applied to a stainless steel foil having low thermal conductivity and difficult to expand, distortion (curl) is likely to occur in the width direction of the stainless steel foil. When heat laminating is performed using such a stainless steel foil, heat is not sufficiently propagated in the plane, and some parts are not in contact with the thermocompression bonding rollers in the width direction, or they are not in contact with the rolls. , The strain itself may cause creases or wrinkles during thermocompression bonding. Further, when the stainless steel foil is heated to a high temperature at which distortion does not occur, the productivity may decrease due to a decrease in the processing speed or an increase in the required amount of heat.
When the dry laminate is used in the production of the battery exterior laminate of the present embodiment, it is possible to suppress the occurrence of breakage and wrinkles and to produce a suitable battery exterior laminate.

The step of forming the first adhesive layer 12 and the step of arranging the first base material layer 11 and performing (dry) laminating are performed by using a (dry) laminating apparatus known as a series of steps. May be good.

The method for forming the second corrosion prevention layer 16, the second adhesive layer 17, and the second base material layer 15 is not particularly limited, but for example, the second adhesive layer 17 is placed on the second base material layer 15 in advance. Is formed into a laminated body composed of two layers. Then, the two-layer laminate and the laminate having the first base material layer 11, the first adhesive layer 12, the first corrosion prevention layer 13, the stainless steel foil 14, and the second corrosion prevention layer 16 are secondly combined. By dry laminating the adhesive layer 17 and the second corrosion prevention layer 16 so as to be in contact with each other, the battery exterior laminate 10 composed of seven layers can be manufactured.

Although one embodiment of the present invention has been described above based on the battery exterior laminate 10 shown in FIG. 1, the technical scope of the present invention is not limited to the above-described embodiment and deviates from the gist of the present invention. It is possible to make various changes to the extent that it does not.
For example, the second corrosion prevention layer 16 may not be provided and may have a six-layer structure.
Further, another layer is provided on the side of the first base material layer 11 that does not come into contact with the first adhesive layer 12 or the side of the second base material layer 15 that does not come into contact with the second adhesive layer 17, and seven layers or It may be composed of eight or more layers.

[Battery exterior]
The battery exterior body of the second aspect of the present invention is a battery exterior body including the battery exterior laminate of the first aspect, has an internal space for accommodating the battery, and is the first of the battery exterior laminates. The battery exterior is such that the base material layer side is the side of the internal space. Specifically, it is obtained by molding the battery exterior laminate 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. It is a thing.
The shape, size, etc. of the battery outer body are not particularly limited, and can be appropriately determined according to the type of battery used.
The battery exterior 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 with reference to FIG. Good.

[battery]
The battery of the third aspect of the present invention includes the battery exterior of the second aspect.
Examples of the battery include a secondary battery such as a lithium ion battery which is a secondary battery, a capacitor such as an electric double layer capacitor, and the like using an organic electrolyte as an electrolytic solution.
As an example, a perspective view of the secondary battery 40 is shown in FIG. The secondary battery 40 is a battery outer container 20 containing a lithium ion battery 27.
In the battery exterior container 20, the container body 30 made of the battery exterior laminate 10 of the first aspect of the present invention and the lid portion 33 made of the battery exterior laminate 10 are overlapped, and the peripheral edge portion 29 is heat-sealed. It is formed by. Reference numeral 28 is an electrode lead connected to the positive electrode and the negative electrode of the lithium ion battery 27.

The battery shown in FIG. 2 can be manufactured as follows.
First, as shown in FIG. 3A, the battery exterior laminate 10 is formed into a tray shape having a recess 31 by drawing or the like to obtain a container body 30. The depth of the recess 31 can be, for example, 2 mm or more.
A lithium ion battery (lithium ion battery 27 in FIG. 2) is housed in the recess 31 of the container body 30.
Next, as shown in FIG. 3B, the lid 33 made of the battery exterior laminate 10 is placed on the container body 30, and the flange 32 of the container body 30 and the peripheral edge 34 of the lid 33 are heat-sealed. By doing so, the secondary battery 40 shown in FIG. 2 can be obtained. That is, in the battery shown in FIG. 3, the upper surface of the container body 30 is covered with the lid portion 33, so that the recess 31 and the lid portion 33 form an internal space for accommodating the battery.

Further, the battery in the present invention can also be manufactured as follows.
First, as shown in FIG. 4A, a part of the rectangular battery exterior laminate 50 on one end side in the longitudinal direction is pressed from the side of the first base material layer of the battery exterior laminate 50 by drawing molding or the like. To obtain a molded body 55 having a recess 51. The depth of the recess 51 can be, for example, 2 mm or more.
Next, although not shown, the lithium ion battery (lithium ion battery 27 in FIG. 2) is housed in the recess 51 of the molded body 55.

Next, the portion of the other end side of the molded body 55 where the recess 51 is not formed is bent toward the first base material layer so as to form a bending line L extending in the lateral direction of the molded body 55. .. Here, in the molded body 55, the region on the recess 51 side with respect to the bending line L is referred to as "first region 551", and the region on the side opposite to the recess 51 with respect to the bending line L is referred to as "second region 552".

Next, the first base material layer around the recess 51 in the first region 551 and the first base material layer (peripheral portion 54) overlapping the circumference 52 in the second region 552 are overlapped. As a result, the second region 552 overlaps the recess 51 of the first region 551.

Next, as shown in FIG. 4 (b), the battery exterior body made of one member is formed by heat-sealing the first base material layer around the recess 51 and the first base material layer in the second region 552. The secondary battery 60 to have is obtained. That is, in the battery shown in FIG. 4B, the upper surface of the recess 51 is covered with the second region 552, so that the recess 51 and the second region 552 form an internal space for accommodating the battery.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these examples.

[Examples 1 to 15, Comparative Examples 1 to 5]
(Examples 1 to 5)
First, a stainless steel foil having a thickness of 20 μm was prepared. A water-soluble paint (coating amount 12 g / m ² ) is applied to both sides of the stainless steel foil, dried by heating in an oven at 200 ° C., and the first corrosion prevention layer and the second corrosion having the thickness shown in Table 1 are shown. Each prevention layer was formed.
Water-soluble coating, a 0.2 wt% poly (vinyl alcohol) backbone containing amorphous polymer having a hydroxyl group, and 0.8% by weight of FeCl ₂ · 4H ₂ O, nitrilotris (methylene phosphonic acid) (trade name: Chelest PH -320, 0.7% by mass of Kirest Co., Ltd. is dissolved in water to form an aqueous solution.

Then, the first adhesive was applied onto the formed first corrosion prevention layer to form a first adhesive layer having a thickness of 3 μm. The first adhesive was 100 parts by mass of maleic anhydride-modified polypropylene (melting point 15 ° C.) and a novolac type epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name: jER157S70, viscosity = 80, epoxy equivalent = 210). It was obtained by melting and kneading 7 parts by mass of the above at room temperature for 10 minutes.

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

Further, a urethane adhesive (main agent: TM-K55 (trade name, manufactured by Toyo Morton Co., Ltd.), cured on a second base material layer made of a stretched polyethylene terephthalate (PET) resin film having a thickness of 6 to 8 μm and having a black color. Agent: A second adhesive layer (thickness 3 μm) made of CAT-10L (trade name, manufactured by Toyo Morton Co., Ltd.) was formed by coating.
The second adhesive layer and the second corrosion prevention layer in the above-mentioned laminate were opposed to each other and laminated by dry lamination at 80 ° C. to obtain a battery exterior laminate.

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 "surface defects".
A: No in-plane defects were observed per 1 m ² .
B: 1 to 5 in-plane defects were observed per 1 m ² .
6 to 10 in-plane defects were observed per C: 1 m ² .
11 or more in-plane defects were observed per D: 1 m ² .

A three-sided seal bag (a three-way seal bag prepared by preparing 3 g of an electrolytic solution (a solution of ethylene carbonate: diethyl carbonate: dimethyl carbonate = 1: 1: 1 vol% to which 1 mol / liter of LiPF ₆ was added) was prepared and used as a laminate for battery exterior. Inner dimensions 30 mm x 50 mm, heat seal width 7 mm) were filled. This three-way seal bag was allowed to stand in a constant temperature bath at 85 ° C. for 2000 hours.
After 2000 hours, the three-way seal bag was opened, and the presence or absence of peeling of the layer inside the metal foil was visually observed, and evaluation was performed according to the following evaluation criteria. The results are shown in Table 1 as "electrolyte resistance".
A: No peeling was observed B: Slight peeling was observed but within the permissible range C: Peeling was observed D: Peeled over the entire surface

Further, the test piece after the immersion in the electrolytic solution was immersed in pure water for 10 hours, then taken out from the pure water, and the state was visually observed. The results of evaluation based on the following evaluation criteria are shown in Table 1 as "after immersion in water".
A: No peeling was observed B: Slight peeling was observed but within the permissible range C: Peeling was observed D: Peeled over the entire surface

A battery exterior laminate was cut into a size of 200 mm × 100 mm to obtain a test piece. This test piece was set in a cold forming apparatus having a size of 100 mm × 50 mm, and embossing was performed under the condition of a drawing depth of 6 mm. The occurrence of breakage and pinholes in the molded stretched portion was observed visually or with an optical microscope. The same test was performed 10 times, and the results of evaluation based on the following evaluation criteria are shown in Table 1 as "moldability".
A: No breakage occurred in the molded stretched portion, and no pinholes occurred.
B: Slight breakage within the permissible range occurred in the molded stretched portion, or 1 to 3 samples out of 10 samples had pinholes.
C: Small breaks occurred in the molded stretched portion, or pinholes were generated in 1 to 5 samples out of 10 samples.
D: A large fracture occurred in the molded stretched portion, or 6 or more samples out of 10 samples had pinholes.

(Examples 6 to 10)
In the first adhesive forming the first adhesive layer, a battery exterior laminate was produced in the same manner as in Example 3 except that the adhesive shown in Table 1 was used, and the same evaluation as in Example 1 was performed. Was done. The results are shown in Table 1.

(Example 11)
A battery exterior laminate was manufactured in the same manner as in Example 3 except that the dry laminate of the first adhesive layer and the first base material layer at 120 ° C. was changed to a thermal laminate at 200 ° C. The same evaluation as in 1 was performed. 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 to 14)
A battery exterior laminate was manufactured in the same manner as in Example 3 except that the stainless steel foil having a thickness of 20 μm was changed to the stainless steel foil having the thickness shown in Table 1, and the same evaluation as in Example 1 was performed. It was. The results are shown in Table 1.

(Example 15)
The battery exterior laminate was prepared in the same manner as in Example 1 except that the first and second corrosion prevention layers were plated with chromium fluoride to obtain the first and second corrosion prevention layers having a thickness of 250 μm. It was manufactured and evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
As the metal foil, an aluminum foil having a thickness of 20 μm is used instead of the stainless steel foil, and as the first adhesive, only maleic anhydride-modified polypropylene (melting point 80 ° C.) is used, and a phenol novolac type epoxy resin is used. A laminate for battery exterior was produced in the same manner as in Example 11 except that an adhesive which was not used was used, and the same evaluation as in Example 1 was performed. The results are shown in Table 1.

(Comparative Example 2)
As the metal foil, in place of the stainless steel foil, an aluminum foil having a thickness of 20 [mu] m, the first and second anti-corrosion layer, 0.8 wt% in place of the FeCl ₂ · 4H ₂ O 0.8 wt% except for using the CrF 3 · _3H 2 _O in the same manner as in example 3, to prepare a battery exterior laminate were evaluated in the same manner as in example 1. The results are shown in Table 1.

(Comparative Example 3)
Lamination for battery exterior in the same manner as in Example 3 except that an adhesive having only maleic anhydride-modified polypropylene (melting point 80 ° C.) and no phenol novolac type epoxy resin was used as the first adhesive. A body was produced and evaluated in the same manner 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 corrosion prevention layer and the second corrosion prevention layer were not provided, and the same evaluation as in Example 1 was performed. The results are shown in Table 1.

(Comparative Example 5)
In the first adhesive forming the first adhesive layer, a battery exterior laminate was produced in the same manner as in Example 3 except that the adhesive shown in Table 1 was used, and the same evaluation as in Example 1 was performed. Was done. The results are shown in Table 1.

In Table 1, each abbreviation has the following meaning.
(BPP): Block polypropylene (rPP): Random polypropylene (Ad-NV1): 100 parts by mass of maleic anhydride-modified polypropylene (melting point 80 ° C.), and novolak epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name: jER154, epoxy equivalent) = 178) 5 parts by mass of toluene solution adhesive (Ad-NV2) having a solid content of 15%: 100 parts by mass of maleic anhydride-modified polypropylene (melting point 80 ° C.) and 2 parts by mass of novolak epoxy resin jER154. Toluene solution adhesive with a solid content of 15% (Ad-NV3): Toluene solution adhesive with a solid content of 15% having 100 parts by mass of maleic anhydride-modified polypropylene (melting point 80 ° C.) and 7 parts by mass of novolak epoxy resin jER154. (Ad-NV4): Toluene solution adhesive having a solid content of 15% having 100 parts by mass of maleic anhydride-modified polypropylene (melting point 80 ° C.) and 10 parts by mass of novolak epoxy resin jER154 (Ad-NV5): maleic anhydride. Toluene solution adhesive (Ad-NV6) having a solid content of 15% and having 100 parts by mass of modified polypropylene (melting point 80 ° C.) and 15 parts by mass of novolak epoxy resin jER154: 100 parts of maleic anhydride-modified polypropylene (melting point 140 ° C.). Adhesive (Ad-BPNV) having 5 parts by mass of novolak epoxy resin jER154 and 100 parts by mass of maleic anhydride-modified polypropylene (melting point 80 ° C.), and a phenol novolac type epoxy resin having a bisphenol A structure (Mitsubishi) Chemical product, trade name: jER157S70, viscosity = 80; epoxy equivalent = 210) and a toluene solution adhesive (Ad-PN) having a solid content of 15% and having a solid content of 15%: 100 of maleic anhydride-modified polypropylene (melting point 80 ° C.) 15% solid content toluene solution adhesive (Ad-PP) having 5 parts by mass and 5 parts by mass of phenoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name: Epicoat 1001, epoxy equivalent = 450): maleic anhydride-modified polypropylene (maleic anhydride-modified polypropylene) Epoxy having 100 parts by mass of melting point 140 ° C. (SUS): Stainless steel foil (AL): Aluminum foil

As is clear from the results shown in Table 1, the battery exterior laminates of Examples 1 to 15 suppress the occurrence of surface defects, reduce peeling even when in contact with an electrolytic solution or water, and are good. It had excellent moldability and had excellent characteristics (workability / moldability, mechanical strength, chemical solution / water resistance) as compared with the battery exterior laminates of Comparative Examples 1 to 5.

[Examples 16 to 24]
In the third embodiment, in place of the 0.8 wt% of FeCl ₂ · 4H ₂ O in the first corrosion-inhibiting layer and the second corrosion-inhibiting layer, a metal halide shown in Table 2 of 0.8 wt% The examples 16 to 24 were examined. The evaluation method and evaluation criteria are the same as those in Example 1. The results are shown in Table 2.

From the results shown in Table 2, it was confirmed that the effects of the present application can be obtained even when various compounds are used as the metal halide compounds.

Claims (10)

A battery exterior laminate comprising at least a first base material layer, a first adhesive layer, a first corrosion prevention layer, a stainless steel foil, and a second base material layer in this order.
The first base material 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 5 to 10 parts by mass of a compound (B) containing a plurality of epoxy groups. A laminated body for battery exterior, which is characterized by this. The battery exterior laminate according to claim 1, wherein the compound containing a plurality of epoxy groups is a phenol novolac type epoxy resin. The laminate for battery exterior according to claim 2, wherein the phenol novolac type epoxy resin has an epoxy equivalent of 100 to 300. The battery exterior laminate according to claim 2 or 3, wherein the phenol novolac type epoxy resin has a bisphenol A structure. The laminate for battery exterior according to any one of claims 1 to 4, wherein the first corrosion prevention layer contains a metal halide compound. The laminate for battery exterior according to claim 5, wherein the metal halide compound is a chloride or fluoride of iron, chromium, manganese or zirconium. The laminate for battery exterior according to any one of claims 1 to 6, wherein the stainless steel foil has a thickness of 10 to 30 μm. The battery exterior laminate according to any one of claims 1 to 7, wherein the first base material layer is homopolypropylene or block polypropylene. A battery exterior body comprising the battery exterior laminate according to any one of claims 1 to 8.
A battery exterior body having an internal space for accommodating a battery, wherein the side of the first base material layer of the battery exterior laminate is the side of the internal space. A battery comprising the battery exterior according to claim 9.

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