CN107123755B

CN107123755B - Laminate for battery exterior packaging, and battery

Info

Publication number: CN107123755B
Application number: CN201610985342.2A
Authority: CN
Inventors: 饭塚宏和; 佐藤友纪; 武井邦浩; 金田康宏; 宫胁晃
Original assignee: Fujimori Kogyo Co Ltd
Current assignee: Fujimori Kogyo Co Ltd
Priority date: 2016-02-25
Filing date: 2016-11-09
Publication date: 2021-12-31
Anticipated expiration: 2036-11-09
Also published as: JP6850539B2; CN107123755A; TW201731142A; KR101868798B1; TWI705596B; JP2017152244A; KR20170100401A

Abstract

The present invention provides a laminate for battery outer packaging which can be produced with high productivity and is excellent in various properties. The laminate (10) for battery outer packaging provided by the present invention comprises at least a first base material layer (11), a first adhesive layer (12), and a metal foil (14) in this order, and is characterized in that the first A base material layer (11) is a layer composed of polyolefin, and the first adhesive layer (12) is an energy storage at 150° C. in the dynamic viscoelasticity measurement of a single layer of the first adhesive layer (12) A layer having a modulus value of 1.0×10 ⁴ or more and 1.0×10 ⁷ or less; the battery outer package provided by the present invention has the battery outer package laminate, characterized in that the battery outer package has a battery housing The inner space of the battery outer packaging body, the side of the first base material layer of the battery outer packaging layer is the inner space side; the battery provided by the present invention is characterized by having the battery outer packaging body.

Description

Laminate for battery exterior packaging, and battery

Technical Field

The present invention relates to a laminate for battery exterior packaging that is excellent as an exterior package for a secondary battery, a capacitor, or the like, and a battery exterior package and a battery obtained using the laminate.

Background

With the growing awareness of the environment, attention is being paid to secondary batteries such as lithium ion batteries and capacitors such as electric double layer capacitors as storage batteries for storing electric energy while utilizing natural energy such as sunlight or wind power.

As an exterior body used for these batteries, a laminate for battery exterior packaging in which a metal foil and a resin layer are laminated is used for the purpose of downsizing and weight reduction. Such a battery exterior laminate is molded by drawing (drawing) or the like into a disk shape having a recess, and is used as an exterior container body. The battery exterior laminate is molded in the same manner as the outer container body to obtain an outer cover. After the battery body is housed in the concave portion of the exterior container body, the exterior lid portion is overlapped so as to cover the housed battery body, and the container body and the side edge portion of the exterior lid portion are bonded to each other, thereby obtaining a battery in which the battery body is housed in the exterior.

For example, patent document 1 discloses a laminate for battery outer packaging in which a base material layer, an aluminum foil, and an innermost layer made of a polypropylene or polyethylene layer are laminated in this order, and a film coating layer is laminated on the surface on the innermost layer side of the aluminum foil. More specifically, in patent document 1, it is preferable that the film coat layer and the innermost layer made of a polypropylene or polyethylene layer are bonded via a heat-sealing agent, and the film-coated aluminum foil and the innermost layer are bonded by a lamination process using an acid-modified polypropylene-based heat-sealing agent.

Documents of the prior art

Patent document

Patent document 1: japanese unexamined patent publication No. 2012-33393

Disclosure of Invention

Technical problem to be solved by the invention

As the field of application of batteries such as secondary batteries expands, there is a demand for an increase in the yield of batteries and an increase in the production efficiency of battery exterior bodies during production, such as an increase in the yield and a reduction in the time. In addition, battery characteristics such as downsizing and capacity increase are improved, and excellent characteristics such as heat resistance and chemical resistance (electrolyte solution resistance) are also required for the battery exterior body.

However, when the surface-treated metal foil and the innermost resin are laminated and bonded using the heat-sealing agent as described in patent document 1, high temperature and high pressure must be added during lamination, and it is difficult to shorten the production time or reduce the production cost, and therefore, there is a limit to the improvement of the production efficiency. Further, when the lamination process is performed at a high temperature, wrinkles or deterioration may occur in the innermost layer (polypropylene layer, polyethylene layer, or the like) or the metal foil to be bonded, which may result in a reduction in yield or a reduction in the range of selection of various materials.

The present invention has been made in view of the above-described situation, and an object thereof is to provide a laminate for battery exterior packaging which can be produced with high production efficiency and has excellent various properties.

Means for solving the problems

As a result of extensive studies to achieve the above object, the present inventors have found that a metal foil having an arbitrary surface finish and a base material layer (innermost layer) are bonded via an adhesive layer having a specific storage modulus, whereby not only various properties required for a laminate for battery exterior packaging can be improved, but also production efficiency can be improved as needed, for example, production time can be shortened, yield can be improved, and the like, and have completed the present invention.

That is, the present invention adopts the following configuration.

The laminate for battery exterior packaging according to the first aspect of the present invention comprises at least a first base material layer, a first adhesive layer, and a metal foil in this order, wherein the first base material layer is a layer comprising a polyolefin, and the first adhesive layer has a storage modulus at 150 ℃ of 1.0 × 10 in a dynamic viscoelasticity measurement of a single layer of the first adhesive layer⁴Above and at 1.0X 10⁷The following layers.

Preferably, 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.

The compound (B) containing a plurality of epoxy groups is preferably a novolak type epoxy resin.

Preferably, a first corrosion prevention layer containing a halogenated metal compound is provided between the first adhesive layer and the metal foil.

The first corrosion prevention layer preferably further contains a water-soluble resin, and a chelating agent or a crosslinkable compound.

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

The metal foil is preferably aluminum, stainless steel, copper, nickel or titanium.

The thickness of the metal foil is preferably 10-40 μm.

A battery exterior package according to a second aspect of the present invention is the battery exterior package laminate according to the first aspect, wherein the battery exterior package has an internal space for housing a battery, and the first base material layer side of the battery exterior package laminate is the internal space side.

A battery according to a third aspect of the present invention is characterized by having the battery exterior body according to the second aspect.

Effects of the invention

According to the present invention, a laminate for battery exterior packaging having excellent characteristics and capable of being produced with high production efficiency can be provided.

Drawings

Fig. 1 is a schematic cross-sectional view showing a first embodiment of a laminate for battery exterior packaging of the present invention;

fig. 2 is a perspective view showing an example of a secondary battery produced using the laminate for exterior packaging of a battery of the present invention;

fig. 3 is a perspective view showing a process of producing a secondary battery using the laminate for external packaging of a battery of the present invention;

fig. 4 is a graph showing the storage modulus of the adhesive layer single layer in experimental examples 1 to 3 and comparative experimental example 1.

Description of the reference numerals

11: a first base material layer; 12: a first adhesive layer; 13: a first anti-corrosion layer; 14: a metal foil; 15: a second anti-corrosion layer; 16: a second adhesive layer; 17: second base material layer

Detailed Description

The present invention will be described below based on preferred embodiments.

[ laminate for packaging Battery ]

The laminate for battery exterior packaging (hereinafter, may be simply referred to as "laminate") according to the first aspect of the present invention includes at least a first base material layer, a first adhesive layer, a first corrosion prevention layer, and a metal foil in this order, the first base material layer being a layer made of polyolefin, and the first adhesive layer being a layer having a storage modulus at 150 ℃ of 1.0 × 10 in the dynamic viscoelasticity measurement of the first adhesive layer single layer⁴Above and at 1.0X 10⁷The following layers.

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

The laminate 10 of the present embodiment includes a first base material layer 11, a first adhesive layer 12, a first corrosion prevention layer 13, a metal foil 14, a second corrosion prevention layer 15, a second adhesive layer 16, and a second base material layer 17 in this order.

That is, the laminate 10 of the present embodiment is composed of seven layers, and includes: the metal foil includes a first corrosion-resistant layer 13 and a second corrosion-resistant layer 15 formed on both surfaces of a metal foil 14, a first base material layer 11 laminated on the first corrosion-resistant layer 13 via a first adhesive layer 12, and a second base material layer 17 laminated on the second corrosion-resistant layer 15 via a second adhesive layer 16.

Each layer is described in detail below.

< first substrate layer 11 >

The first base material layer 11 is a layer made of polyolefin. Examples of the layer composed of a polyolefin include polyethylene, polypropylene, poly-1-butene, polyisobutylene, a random copolymer of propylene and ethylene or an α -olefin, and a block copolymer of propylene and ethylene or an α -olefin.

Among them, polypropylene resins such as homopolypropylene (propylene homopolymer; hereinafter, sometimes referred to as "homopolypp"), a propylene-ethylene block copolymer (hereinafter, sometimes referred to as "block PP"), and a propylene-ethylene random copolymer (hereinafter, sometimes referred to as "random PP") are preferable because of improved adhesiveness to the first adhesive layer 12. Among these, homopolypropylene and block PP are more preferable, and block PP is particularly preferable because of its excellent mechanical strength.

The first substrate layer 11 may have a single-layer structure or a multilayer structure.

The melting point of the layer composed of the polyolefin used for the first substrate layer 11 is not particularly limited as long as it has heat resistance necessary for the battery exterior laminate 10.

The thickness of the first base material layer 11 may be, for example, 1 to 200 μm, preferably 5 to 100 μm, and more preferably 5 to 40 μm.

< first adhesive layer 12 >

The first adhesive layer 12 is a layer provided for bonding a first base material layer 11 as a base resin layer and a metal foil 14 having a first corrosion prevention layer 13 formed on the surface thereof, and the value of the storage modulus at 150 ℃ in the dynamic viscoelasticity measurement of a single layer of the first adhesive layer 12 is 1.0 × 10⁴Above and at 1.0X 10⁷The following.

The material of the adhesive forming the first adhesive layer 12 is not particularly limited as long as the above-described layer can be satisfactorily adhered thereto and as long as the layer satisfies the value of the storage modulus, but for example, a layer composed of an adhesive containing an acid-modified polyolefin resin (a) and a compound (B) containing a plurality of epoxy groups is preferable from the viewpoint of satisfying the adhesiveness and the storage modulus.

Hereinafter, the acid-modified polyolefin resin (a) may be referred to as "component (a)" and the compound (B) having 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) (component (a)) is a polyolefin resin modified with an unsaturated carboxylic acid or a derivative thereof, and the polyolefin resin has an acidic functional group such as a carboxyl group or a carboxylic acid anhydride group.

(A) The component (B) is obtained by modifying a polyolefin resin with an unsaturated carboxylic acid or a derivative thereof, or by copolymerizing an acidic functional group-containing monomer with an olefin. Among them, the polyolefin-based resin is preferably obtained by acid-modifying the polyolefin-based resin as the component (A).

Examples of the acid modification method include graft modification in which a polyolefin resin and an acidic 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 resin include polyethylene, polypropylene, poly-1-butene, polyisobutylene, a copolymer of propylene and ethylene, and a copolymer of propylene and an olefin monomer.

Examples of the olefin monomer to be copolymerized include 1-butene, isobutene, and 1-hexene.

The copolymer may be a block copolymer or a random copolymer.

Among them, the polyolefin-based resin is preferably a polypropylene-based resin polymerized from propylene, such as homopolypropylene (propylene homopolymer), a copolymer of propylene and ethylene, or a copolymer of propylene and butene, and particularly preferably a propylene-1-butene copolymer, that is, a polyolefin resin having a methyl group and an ethyl group in a side chain. By containing 1-butene, the molecular movement during heating of the resin is promoted, and the chance of contact between the crosslinking points of the component (a) and the component (B) described later is increased, resulting in further improvement in adhesion to an adherend.

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

Examples of the acid functional group-containing monomer having a carboxyl group (carboxyl group-containing monomer) include α, β -unsaturated carboxylic acid monomers such as acrylic acid, methacrylic acid, maleic acid, nadic acid (nadic acid), fumaric acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, tetrahydrophthalic acid, endo-bicyclo [2.2.1] -5-heptene-2, 3-dicarboxylic acid (endic acid).

Examples of the acid functional group-containing monomer having a carboxylic anhydride group (carboxylic anhydride group-containing monomer) include unsaturated dicarboxylic anhydride monomers such as maleic anhydride, nadic anhydride, itaconic anhydride, citraconic anhydride and nadic anhydride.

These acid functional group-containing monomers may be used alone or in combination of two or more kinds in the component (A).

Among these, the acidic functional group-containing monomer is preferably a monomer containing an acidic functional group which reacts favorably with an epoxy group in the component (B) described later, and is more preferably an acidic functional group-containing monomer having an acid anhydride group, even more preferably a carboxylic acid anhydride group-containing monomer, and particularly preferably maleic anhydride, because of its high reactivity with an epoxy group.

In order to prevent a decrease in adhesive strength due to the unreacted acidic functional group-containing monomer when a part of the acidic functional group-containing monomer used for acid modification is unreacted, it is preferable to use a substance from which the unreacted acidic functional group-containing monomer is removed in advance as the component (a).

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

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

When the first adhesive layer 12 is used as a dry lamination adhesive layer, the melting point of the component (A) is preferably 50 to 100 ℃, more preferably 60 to 98 ℃, even more preferably 70 to 98 ℃, and even more preferably 75 to 95 ℃.

When the melting point of the component (a) is not less than the lower limit, the heat resistance of the first adhesive layer 12 can be improved, and as a result, the heat resistance and durability after the first base material layer 11 and the metal foil 14 having the first corrosion prevention layer 13 are bonded via the first adhesive layer 12 can be improved.

On the other hand, when the melting point of the component (a) is not more than the above upper limit, the component (a) is easily dissolved in an organic solvent to obtain a solvent-based adhesive for dry lamination, whereby a more uniform adhesive can be obtained, and the component (a) and the component (B) can be reacted well to improve the adhesiveness and the durability. By using the component (a) having a melting point of not more than the above upper limit, the temperature at the time of dry lamination via the first adhesive layer 12 or the curing temperature after lamination can be set to a relatively low temperature. As a result, wrinkles are less likely to occur in the first base material layer 11 bonded using the first adhesive layer 12 due to heat, and the heat resistance requirement of the first base material layer 11 is relaxed as well as the yield in production is improved, so that the range of selection of the material for the first base material layer 11 can be widened. Further, the laminating process at a relatively low temperature can be performed, and as a result, the time for the laminating process can be shortened, and the energy required for the laminating process can be reduced, so that the production efficiency can be improved and the energy consumption can be reduced.

On the other hand, when the adhesive for forming the first adhesive layer 12 does not contain an organic solvent and is formed by melt-kneading the component (a) and the component (B) described later, the melting point of the component (a) is preferably 100 to 180 ℃. The first adhesive layer 12 made of the adhesive can be suitably used as an adhesive layer for thermal lamination.

By using the component (a) having a melting point within the above range, the component (a) and the component (B) described later can be melt kneaded at a temperature sufficiently higher than the melting point of the component (a) even when a usual method and a usual apparatus are used. When the component (a) is reacted with the component (B) described later by melt kneading, the melting point of the component (B) is preferably lower than that of the component (a), but the degree of freedom in selecting the component (B) can be increased by using the component (a) having the melting point in the above range.

The melting point of component (a) is preferably higher than the melting point of component (B) described later, as described above, but the melting point of component (a) is more preferably higher than the melting point of component (B) by 10 ℃ or more, still more preferably higher than 20 ℃ or more, and particularly preferably higher than 30 ℃ or more. When the melting point of the component (a) is sufficiently higher than that of the component (B), the component (B) melts first and permeates into the component (a) in a state where the resin shape is maintained at the time of melt kneading, and as a result, the component (a) and the component (B) react uniformly, and as a result, excellent durability can be obtained.

(A) The molecular weight of the component (B) is not particularly limited as long as the above-mentioned desired melting point can be satisfied, and a resin having a molecular weight of 10000 to 800000 is usually used, preferably 50000 to 650000, more preferably 80000 to 550000, and further preferably 100000 to 450000.

Among these, maleic anhydride-modified polypropylene is preferable as the component (a) from the viewpoint of adhesiveness, durability, and the like.

(Compound (B) having plural epoxy groups)

(B) The component (A) is a compound containing a plurality of epoxy groups. (B) The component (C) may be a low-molecular compound or a high-molecular compound. The component (B) is preferably a polymer compound (resin) from the viewpoint of good miscibility and compatibility with the component (a). On the other hand, when the adhesive is a solvent-based adhesive for dry lamination, the component (B) is preferably a low molecular compound in view of good solubility in an organic solvent.

(B) The structure of the component (a) is not particularly limited as long as it has a plurality of epoxy groups, and examples thereof include phenoxy resins synthesized from bisphenols and epichlorohydrin; a novolac epoxy resin; bisphenol type epoxy resins, and the like. Among them, a novolac epoxy resin is preferably used because it has a high epoxy group content per molecule and can form a particularly dense crosslinked structure together with the component (a).

In the present invention, the novolac epoxy resin is a compound having a basic structure of a novolac resin obtained by acid condensation of phenol and formaldehyde, 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 is generally a polyfunctional epoxy resin because a large amount of epoxy groups are introduced into phenolic hydroxyl groups present in the novolac resin by reacting an epoxy-based raw material such as epichlorohydrin with the novolac resin.

Among them, as the novolac epoxy resin, a bisphenol a novolac epoxy resin having a novolac structure as a basic skeleton and simultaneously having a bisphenol a structure is preferable. The bisphenol a structure in the epoxy resin may be derived from bisphenol a, and the hydroxyl groups at both ends of bisphenol a may be substituted with groups such as epoxy-containing groups.

As an example of the bisphenol a novolac epoxy resin, a resin represented by the following general formula (1) can be exemplified.

[ chemical formula 1]

[ in the formula (1), R¹～R⁶Each independently is a hydrogen atom or a methyl group, n is an integer of 0 to 10, R^XIs a group having an epoxy group.]

In the formula (1), R¹～R⁶Each independently is a hydrogen atom or a methyl group. When n is an integer of 2 or more, R³、R⁴Each may be the same or different.

In the resin represented by the formula (1), at least one of the following (i) to (iii) is preferably satisfied.

(i)R¹And R²Both are methyl; (ii) r³And R⁴Both are methyl; (iii) r⁵And R⁶Are methyl groups.

For example, by satisfying the above (i), in the formula (1), R is bonded¹And R²The carbon atom (b) and the two hydroxyphenyl groups bonded to the carbon atom constitute a structure derived from bisphenol A.

In the formula (1), R^XIs 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 among them, a glycidyl group is preferable.

The bisphenol A novolac epoxy resin preferably has an epoxy equivalent of 100 to 300, more preferably 200 to 300. The epoxy equivalent (g/eq) is the molecular weight of the epoxy resin per epoxy group, and the smaller the value, the more epoxy groups in the resin. By using an epoxy resin having a small epoxy equivalent, the adhesiveness of the epoxy resin to an adherend is good and the epoxy resin and the acid-modified polyolefin resin are sufficiently crosslinked even when the amount of the epoxy resin added is made small.

As such novolak type epoxy resins, jER154, jER157S70, jER-157S 65; commercially available products such as EPICLON N-730A, EPICLON N-740, EPICLON-770 and EPICLON-775 (trade names thereof) manufactured by DIC corporation.

By using the epoxy resin, both the acidic functional group of the component (a) and the epoxy group of the component (B) function as adhesive functional groups for an adherend (particularly, functional groups such as a carboxyl group of the first corrosion prevention layer 13), whereby excellent adhesion can be exhibited to the first base material layer 11 and the metal foil 14 having the first corrosion prevention layer 13 on the surface.

Further, a part of the acidic 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) in the first adhesive layer 12, and as a result, the strength of the first adhesive layer 12 is enhanced by the crosslinked structure, and excellent adhesion and good durability can be obtained.

The first adhesive layer 12 preferably contains 1 to 20 parts by mass of the component (B) per 100 parts by mass of the component (A); more preferably, the composition contains 5 to 10 parts by mass of the component (B) per 100 parts by mass of the component (A); particularly, it is preferable that the component (B) is contained in an amount of 5 to 7 parts by mass based on 100 parts by mass of the component (A).

(optional Components)

The adhesive used in the present invention may or may not contain an organic solvent.

The solvent-based dry laminating adhesive can be prepared by forming a liquid adhesive by containing an organic solvent. The first adhesive layer 12 can be formed by applying such a liquid adhesive to a layer as a lower layer (for example, the surface of the metal foil 14 on which the first corrosion-resistant layer 13 is provided) and drying the applied liquid adhesive. By selecting coating instead of extrusion molding, the adhesive layer can be formed in a thinner layer, and thinning of the adhesive layer and thinning of the entire laminate using the adhesive layer are possible.

On the other hand, when the organic solvent is not contained, an adhesive layer suitable for heat lamination or the like can be formed by melt kneading the component (a) and the component (B) and then extrusion molding or the like.

When the organic solvent is contained, the organic solvent used is not particularly limited as long as it can dissolve the above-mentioned component (a), component (B) and, if necessary, other optional components (details will be described later) appropriately to prepare a uniform solution, and any solvent can be used from among known solvents as solvents for solution adhesives. The liquid adhesive can be generally used by applying it to an adherend (for example, the surface of the metal foil 14 on which the first corrosion-resistant layer 13 is provided) and then evaporating the organic solvent by heating or the like. Therefore, from the viewpoint of easy volatilization, the organic solvent is preferably an organic solvent having a boiling point of 150 ℃ or lower.

Specific examples of the organic solvent include aromatic solvents such as toluene, xylene, anisole, ethylbenzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenetole, butylphenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, cymene, mesitylene, etc.; aliphatic solvents such as n-hexane; ketone solvents such as methyl ethyl ketone, acetone, cyclohexanone, methyl n-pentanone, methyl iso-pentanone, and 2-heptanone; ester solvents such as methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, and ethyl ethoxypropionate; alcohol solvents such as methanol, ethanol, and isopropanol; polyhydric alcohol solvents such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol.

The organic solvent may be used alone or in combination of two or more kinds thereof. When the component (a) is used as a mixed solvent, it is preferable to use an organic solvent in which the component (a) is well dissolved and an organic solvent in which the component (B) is well dissolved in combination. The combination is preferably a combination of toluene in which the component (a) is well dissolved and methyl ethyl ketone in which the component (B) is well dissolved. When a mixed solvent is used, two or more organic solvents may be mixed in advance, and the component (a), the component (B), and the like may be dissolved; the components (a) and (B) may be dissolved in respective good solvents, and then a plurality of organic solvents in which the components are dissolved may be mixed.

When a plurality of organic solvents are mixed and used, the ratio of each organic solvent is not particularly limited, and when toluene and methyl ethyl ketone are used in combination, the mixing ratio is preferably 60 to 95:5 to 40 (mass ratio) of toluene to methyl ethyl ketone, and more preferably 70 to 90:10 to 30 (mass ratio) of toluene to methyl ethyl ketone.

The adhesive used in the present invention may contain other components in addition to the above-mentioned component (a), component (B) and organic solvent. As the other component, an additive having mixing property or an additional resin may be mentioned, and more specifically, a catalyst, a crosslinking agent, a plasticizer, a stabilizer, a colorant, and the like may be used.

The solid content of the adhesive used in the present invention preferably contains more than 50 parts by mass and 99.5 parts by mass or less of component (a), and 0.5 parts by mass or more and less than 50 parts by mass of component (B). That is, the amount of the component (a) in the solid content of the adhesive is more than half of the mass ratio, and the adhesive used in the present invention contains the component (a) as a main component. More preferably 70 to 99.5 parts by mass of the component (A), the component (B) is 0.5 to 30 parts by mass, still more preferably 80 to 99 parts by mass of the component (A), the component (B) is 1 to 20 parts by mass, particularly preferably 90 to 98 parts by mass of the component (A), and the component (B) is 2 to 10 parts by mass.

When the adhesive used in the present invention contains a solid component other than the components (a) and (B) as an optional component, the component (a) must be a main component. Therefore, even when the adhesive contains any component, the amount of the component (a) exceeds 50 parts by mass in the total solid content of the adhesive. For example, the adhesive contains 70 to 99.5 parts by mass of the component (A), 0.5 to 29.5 parts by mass of the component (B) and 0.5 to 29.5 parts by mass of other components in the total solid content.

When the adhesive used in the present invention contains an organic solvent, the amount of the organic solvent used is not particularly limited as long as the organic solvent can dissolve each component (a), (B), and any component well, but the solid content concentration is usually preferably 3 to 30% by mass, more preferably 5 to 25% by mass, and still more preferably 7 to 20% by mass.

The adhesive used in the present invention has a storage modulus at 150 ℃ of 1.0 × 10 in the measurement of dynamic viscoelasticity of a single layer of the first adhesive layer 12 formed using the adhesive⁴～1.0×10⁷More preferably 5.0X 10⁴～9.5×10⁵More preferably 3.0X 10⁵～8.0×10⁵。

In the measurement of the dynamic viscoelasticity of the single layer of the first adhesive layer 12 formed using the adhesive, the value of the storage modulus at 60 ℃ is preferably 1.0 × 10⁶Above, more preferably 1.0 × 10⁶～1.0×10⁸More preferably 5.0X 10⁶～5.0×10⁷。

That is, the storage modulus value at 150 ℃ is preferably 1/10000 to 1/1, more preferably 1/1000 to 1/1, still more preferably 1/500 to 1/1, and particularly preferably 1/100 to 1/1, relative to the storage modulus value at 60 ℃.

That is, the adhesive used in the present invention preferably has a sufficient elastic modulus at 60 ℃ and an elastic modulus in an appropriate range that is not excessively lowered even at a high temperature of 150 ℃. Since the first adhesive layer 12 formed using an adhesive having such a storage modulus is less likely to change in shape even at a relatively high temperature and maintains the shape satisfactorily, the shape, adhesiveness, and the like of the battery exterior laminate 10 having the first adhesive layer 12 can be maintained satisfactorily at a high temperature, and a battery exterior laminate 10 having satisfactory high-temperature resistance can be obtained.

The adhesive having the storage modulus can be easily obtained by using the component (a) and the component (B) in combination. This is because the elastic modulus can be maintained even at a high temperature by crosslinking the acidic functional group of the component (a) with the epoxy group of the component (B).

The value of the storage modulus in the dynamic viscoelasticity measurement can be measured, for example, as follows.

First, an adhesive agent was applied to an arbitrary substrate to which a fluororesin or the like was not bonded, the substrate was heated at 110 ℃ for 300 seconds to dry the adhesive agent (completely volatilize the organic solvent), and after 3 days of aging treatment (complete crosslinking) at 80 ℃, the substrate was peeled off to form an adhesive layer (corresponding to the first adhesive layer 12 single layer) having a thickness of 0.3 mm. The storage modulus can be measured by measuring the formed adhesive layer using a known dynamic viscoelasticity measuring apparatus. As the dynamic viscoelasticity measuring apparatus, a dynamic viscoelasticity measuring apparatus "RSA-3" (trade name) manufactured by TA Instrument Co., Ltd., or the like can be used. The vibration frequency at which the storage modulus is measured is, for example, 1 Hz.

The thickness of the first adhesive layer 12 may be, for example, 0.1 to 50 μm, preferably 0.5 to 10 μm, and more preferably 0.7 to 5 μm. By setting the thickness to this range, the first base material layer 11 and the metal foil 14 provided with the first corrosion prevention layer 13 can be bonded with high adhesion, and interlayer peeling can be prevented.

< first anti-corrosion layer 13 >

In this embodiment, the first corrosion prevention layer 13 is a layer for preventing corrosion due to rust or the like of the metal foil 14.

The first corrosion prevention layer 13 preferably contains a halogenated metal compound, and a halogenated metal compound described later may be directly plated on the surface of the metal foil 14. By providing such a first corrosion prevention layer 13, a good rust prevention effect can be imparted to the metal foil.

The first corrosion prevention layer 13 preferably contains a water-soluble resin, a chelating agent, or a crosslinkable compound in addition to the halogenated metal compound. Therefore, the first corrosion-prevention layer 13 preferably contains a halogenated metal compound, a water-soluble resin, and a chelating agent or a crosslinkable compound, and the first corrosion-prevention layer 13 is also preferably formed by applying an aqueous solution containing a halogen compound, a water-soluble resin, and a chelating agent or a crosslinkable compound onto the layer as the lower layer, followed by drying and curing. Hereinafter, the material forming the first corrosion prevention layer 13 may be referred to as "corrosion prevention treatment agent".

(halogenated Metal Compound)

The halogenated metal compound has an effect of improving chemical resistance such as electrolytic solution resistance. That is, the surface of the metal foil 14 can be passivated, and the corrosion resistance to the electrolytic solution can be improved. When the first corrosion prevention layer 13 contains a water-soluble resin described later, the metal halide compound also has a function of crosslinking the water-soluble resin.

The metal halide compound is preferably water-soluble in view of compatibility with a water-soluble resin described later or in view of the case of being applied by dispersing in a water-soluble medium.

Examples of the metal halide compound include a chromium halide, an iron halide, a zirconium halide, a titanium halide, a hafnium halide, a titanium hydrohalide, and salts thereof. Examples of the halogen atom include chlorine, bromine and fluorine, and chlorine or fluorine is preferred. Further, fluorine is particularly preferable. By containing fluorine in the halogenated metal compound, hydrofluoric acid (HF) can be generated from the corrosion preventing treatment agent depending on the conditions.

The metal halide compound may have atoms other than halogen atoms and metals.

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

(Water-soluble resin)

As the water-soluble resin, at least one selected from the group consisting of a polyvinyl alcohol resin or a derivative thereof, and a polyvinyl ether resin is preferably used.

The polyvinyl alcohol resin or its derivative is preferably a polyvinyl alcohol resin or a modified polyvinyl alcohol resin.

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

Examples of the polymer or copolymer of the vinyl ester monomer include homopolymers or copolymers of 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, and copolymers of other monomers copolymerizable therewith.

Examples of the other copolymerizable monomer include olefins such as ethylene and propylene, ether group-containing monomers such as alkyl vinyl ether, carbonyl (ketone group) -containing monomers such as diacetone acrylamide, diacetone (meth) acrylate, allyl acetoacetate, and acetoacetate, 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.

These monomers can be polymerized by a usual method.

Examples of the modified polyvinyl alcohol resin include alkyl ether-modified polyvinyl alcohol resins, carbonyl-modified polyvinyl alcohol resins, acetoacetyl-modified polyvinyl alcohol resins, acetamide-modified polyvinyl alcohol resins, acrylonitrile-modified polyvinyl alcohol resins, carboxyl-modified polyvinyl alcohol resins, silicone-modified polyvinyl alcohol resins, and ethylene-modified polyvinyl alcohol resins.

Among them, acid-modified polyvinyl alcohol resins such as carboxyl-modified polyvinyl alcohol resins and acetoacetyl-modified polyvinyl alcohol resins are preferable.

The saponification degree of the polyvinyl alcohol resin or the modified polyvinyl alcohol resin is preferably 90 mol% or more, more preferably 90 to 99.9 mol%, and still more preferably 95 to 99 mol%.

The (modified) polyvinyl alcohol resin can react well with the surface of the metal foil by having both a hydrophobic group derived from a vinyl ester side chain (for example, in the case of vinyl acetate, the hydrophobic group is an acetyl group) and a hydrophilic hydroxyl group obtained by saponification, compared with a resin having a saponification degree of 100 mol%, that is, having only a hydrophilic hydroxyl group.

Examples of commercially available products of polyvinyl alcohol resins or derivatives thereof that are generally available include JAPAN VAM & POVAL CO., J-POVAL DF-20 manufactured by LTD, AP-17 (both trade names), NIPPON CARBIDE INDUSTRES Co., CROSSMER H series (trade name) manufactured by Inc. The polyvinyl alcohol resin or its derivative may be used alone or in a mixture of two or more.

Examples of the polyvinyl ether resin include homopolymers or copolymers of aliphatic vinyl ethers such as 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, 2-hydroxyethyl vinyl ether and diethylene glycol monovinyl ether, and copolymers of other monomers copolymerizable with these. Examples of the other monomer copolymerizable with the vinyl ether monomer include the same monomers as those copolymerizable with the vinyl ester monomer.

In particular, a polyvinyl ether resin containing an aliphatic vinyl ether having a hydroxyl group in a monomer, such as 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 2-hydroxypropyl vinyl ether, and other various monovinyl ethers of dihydric or polyhydric alcohols, is suitable for use in the present invention because it is water-soluble and can undergo a crosslinking reaction with a hydroxyl group.

Since these polyvinyl ether resins can be used in the resin production (polymerization) step, they can be produced without saponification, unlike polyvinyl alcohol resins produced via vinyl ester polymers. Further, a copolymer containing a vinyl ester monomer and a vinyl ether monomer, or a vinyl alcohol-vinyl ether copolymer obtained by saponifying these monomers can be used. A mixture of a polyvinyl alcohol-based resin other than the polyvinyl ether-based resin and a polyvinyl ether-based resin may also be used.

As the water-soluble resin, either one of the polyvinyl alcohol resin or its derivative and the polyvinyl ether resin may be used alone, or both of them may be used simultaneously.

(chelating agent)

The chelating agent is a material capable of forming a metal ion complex by coordinately binding with a metal ion.

Since the chelating agent binds the metal compound (e.g., chromium oxide) derived from the halogenated metal compound to the water-soluble resin to increase the compressive strength of the first corrosion-prevention layer 13, the first corrosion-prevention layer 13 is not embrittled and does not crack or peel even when the thickness of the first corrosion-prevention layer 13 exceeds 0.2 μm and is 1.0 μm or less, for example. Therefore, the adhesive strength and adhesion between the metal foil 14 and the first adhesive layer 12, and the adhesive strength and adhesion between the metal foil 14 and the layer on the upper layer side thereof can be improved.

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

Examples of the chelating agent include aminocarboxylic acid chelating agents, phosphonic acid chelating agents, hydroxycarboxylic acid (oxycarbonic acid) chelating agents, and (poly) phosphoric acid chelating agents.

Examples of the aminocarboxylic acid-based chelating agent include nitrilotriacetic acid (NTA), hydroxyethyliminodiacetic acid (HIDA), ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), triethylenetetraminehexaacetic acid (TTHA), transcyclohexanediamine tetraacetic acid (CyDTA), 1, 2-propanediamine tetraacetic acid (1,2-PDTA), 1, 3-propanediamine tetraacetic acid (1,3-PDTA), 1, 4-butanediamine tetraacetic acid (1,4-BDTA), 1, 3-diamino-2-hydroxypropanetetraacetic acid (DPTA-OH), Glycol 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), Methylglycinediacetic acid (MGDA), L-aspartic acid-N, N-diacetic acid (ASDA), L-glutamic acid-N, N-diacetic acid (GLDA), N '-bis (2-hydroxybenzyl) ethylenediamine-N, N' -diacetic acid (HBEDDA).

The phosphonic acid chelating agent is any chelating agent having a phosphonic acid group (HP (═ O) (OH)₂) derivatized-P (═ O) (OH)₂The compound having a structure is not particularly limited, and examples thereof include N, N-trimethylene phosphonic acid (NTMP), 1-hydroxyethylidene-1, 1-diphosphonic acid (HEDP), ethylenediamine-N, N' -tetramethylene phosphonic acid (EDTMP), diethylenetriamine pentamethylene phosphonic acid (DTPMP), 2-phosphonobutane-1, 2, 4-tricarboxylic acid (PBTC), and nitrilotris (methylene phosphonic acid) (NTMP).

Examples of the hydroxycarboxylic acid chelating agent include glycolic acid (glycolic acid), citric acid, malic acid, gluconic acid, and glucoheptonic acid.

Examples of the (poly) phosphoric acid 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 aminocarboxylic acid chelating agents such as Chelest PD-4H (PDTA); phosphonic acid chelating agents such as Chelest PH-540(EDTMP), Chelest PH-210(HEDP), Chelest PH-320(NTMP), and Chelest PH-430(PBTC) (all of which are chelating agents manufactured by Chelest Co., Ltd., labeled as trade names).

Among them, the chelating agent is preferably a chelating agent (phosphate compound) of a phosphate such as a phosphate chelating agent or a (poly) phosphate chelating agent, and more preferably a phosphate chelating agent.

(crosslinkable Compound)

The crosslinkable compound means a compound capable of reacting with the water-soluble resin to form a crosslinked structure. By using such a crosslinkable compound, the water-soluble resin and the crosslinkable compound can form a dense crosslinked structure in the first corrosion-prevention layer 13, and the passivation property and the corrosion resistance of the surface of the metal foil 14 can be further improved.

The crosslinkable compound is not particularly limited as long as it can react with a hydrophilic group (for example, a carboxyl group, a carboxylic acid group, or the like) in the water-soluble resin to form a crosslinked structure, and examples thereof include a compound having an epoxy group and a compound having an oxazoline group.

As the compound having an epoxy group, the same compound as "compound (B) containing a plurality of epoxy groups" described in the description of the adhesive of the first adhesive layer 12 can be used.

The term "compound having an oxazoline group" means a compound having an oxazoline group in the structure (in the oxazoline ring (C)₃H₅NO) a monovalent group having an atomic bond at the 2-position).

Specific examples of the oxazoline group-containing compound include oxazoline group-containing styrene resins, and when a water-soluble resin has a carboxyl group, the following crosslinking reaction occurs to form an amide ester bond. As a result, the strength of the water-soluble resin and the first corrosion prevention layer 13 is enhanced by the crosslinked structure, and excellent corrosion prevention performance is obtained.

[ chemical formula 2]

Among them, as the oxazoline group-containing compound, a resin obtained by copolymerizing a styrene monomer and an oxazoline group-containing monomer is preferable.

As the styrene-based monomer, styrene and its derivatives can be used. Specific examples thereof include alkylstyrenes such as styrene, α -methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene, and octylstyrene; halogenated styrenes such as chlorostyrene, fluorostyrene, bromostyrene, dibromostyrene, iodostyrene, and the like. Among them, styrene is preferable.

The oxazoline group-containing monomer is not particularly limited in its skeleton as long as it is a monomer that contains an oxazoline group and is copolymerizable with a styrene monomer, but a monomer having an oxazoline group and a vinyl group can be suitably used.

Examples of oxazoline group-containing vinyl monomers include 2-vinyl-2-oxazoline, 5-methyl-2-vinyl-2-oxazoline, 4-dimethyl-2-vinyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 4-dimethyl-2-isopropenyl-2-oxazoline, 4-acryloyl-hydroxymethyl-2, 4-dimethyl-2-oxazoline, 4-methacryloyl-hydroxymethyl-2-phenyl-4-methyl-2-oxazoline, and mixtures thereof, 2- (4-vinylphenyl) -4, 4-dimethyl-2-oxazoline, 4-ethyl-4-hydroxymethyl-2-isopropenyl-2-oxazoline, 4-ethyl-4-ethoxycarbonylmethyl-2-isopropenyl-2-oxazoline, and the like. Among them, 2-isopropenyl-2-oxazoline is preferable.

The styrene monomer and the oxazoline group-containing monomer may be used singly or in combination of two or more.

The oxazoline group-containing compound may contain one or more other monomers in addition to the vinyl monomer and the oxazoline group-containing monomer. The other monomer is not particularly limited as long as it is copolymerizable with these monomers, and examples thereof include (meth) acrylate monomers, (meth) acrylate ester monomers, (meth) acrylamide monomers, and the like.

In the oxazoline group-containing compound, the proportion of each monomer is not particularly limited, but a resin obtained by copolymerizing 5 to 50 mass%, more preferably 10 to 30 mass% of an oxazoline group-containing monomer with respect to the total monomers constituting the oxazoline group-containing compound is preferable. By using the oxazoline group-containing monomer in the above range, the water-soluble resin and the oxazoline group-containing compound can be sufficiently crosslinked, and a good corrosion resistance can be obtained.

The number average molecular weight of the oxazoline group-containing compound is preferably 3 to 25 ten thousand, more preferably 5 to 20 ten thousand, further preferably 6 to 10 ten thousand, and most preferably 6 to 8 ten thousand. By using the oxazoline group-containing compound having a number average molecular weight within the above range, the compatibility of the acid-modified polyolefin resin with the oxazoline group-containing compound can be improved, and the water-soluble resin can be sufficiently crosslinked with the oxazoline group-containing compound.

As such an oxazoline group-containing compound, commercially available products such as eporos RPS-1005 (trade name) manufactured by Nippon catalyst Co., Ltd.

In the corrosion-preventing treatment agent, either one of the chelating agent and the crosslinkable compound may be used, or both of them may be used. Among them, it is preferable to use any one of a chelating agent and a crosslinkable compound in combination with the above-mentioned halogenated metal compound and water-soluble resin.

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 of the total solid content of the corrosion-inhibiting treatment agent. In addition, the amount of the metal halide compound in the total solid content of the anticorrosive treatment agent is preferably 20 to 60% by mass, more preferably 30 to 55% by mass, and still more preferably 40 to 50% by mass. The chelating agent and/or the crosslinkable compound is preferably 20 to 60% by mass, more preferably 30 to 50% by mass, and still more preferably 35 to 45% by mass of the total solid content of the anticorrosive treatment agent.

The anticorrosive treatment agent can be prepared by dissolving a water-soluble resin, a halogenated metal compound, and a chelating agent and/or a crosslinkable compound in an aqueous solvent. As the solvent, water is preferable.

The solid content concentration in the corrosion-preventing agent may be appropriately determined in consideration of the coatability of the first corrosion-preventing layer 13, but may be usually 0.1 to 10% by mass.

The thickness of the first corrosion prevention layer 13 is preferably 0.05 μm or more, and more preferably more than 0.1 μm. By setting the thickness of the first corrosion prevention layer 13 to 0.05 μm or more, the adhesion strength between the metal foil 14 and the first adhesive layer 12 and the adhesion strength between the metal foil 14 and the first base material layer 11 can be improved while providing sufficient corrosion resistance to the battery exterior laminate 10.

The thickness of the first corrosion prevention layer 13 is preferably 1.0 μm or less, and 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 adhesion strength between the metal foil 14 and the first adhesive layer 12 can be improved, and the material cost can be suppressed.

< Metal foil 14 >

The metal foil 14 plays an important role in the battery exterior laminate 10 in order to reduce leakage of the contents sealed in the laminate (for example, liquid leakage of the battery). Further, by using a metal having high mechanical strength, when the battery housing recess is formed by drawing using the laminate 10 for battery exterior packaging, the occurrence of pinholes can be reduced, and as a result, leakage of the contents sealed in the laminate (for example, liquid leakage of the battery) can be reduced.

The metal foil 14 is not particularly limited as long as it is a metal foil obtained by thinly stretching a metal or an alloy, and examples thereof include metal foils of aluminum, copper, lead, zinc, iron, nickel, titanium, chromium, and the like; and alloy foils such as stainless steel. The stainless steel foil is not particularly limited as long as it is made of stainless steel such as austenite stainless steel, ferrite stainless steel, or martensite stainless steel. As austenite group, SUS304, SUS316, SUS301, etc.; examples of the ferrite include SUS 430; examples of the martensite include SUS 410.

Among them, aluminum foil or stainless steel foil is preferable from the viewpoint of workability, ease of handling, price, strength (piercing strength, tensile strength, etc.), corrosion resistance, etc., and stainless steel foil is particularly preferable from the viewpoint of piercing strength.

The thickness of the metal 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 lower limit value or more, the battery exterior laminate 10 can be provided with sufficient mechanical strength, and when used in a battery such as a secondary battery, the durability of the battery can be improved. By setting the thickness of the metal foil 14 to the upper limit or less, the battery exterior laminate 10 can be made sufficiently thin and sufficient drawing workability can be provided.

< second anti-corrosion layer 15 >

The second corrosion prevention layer 15 has the same structure as the first corrosion prevention layer 13. In this embodiment, the second corrosion prevention layer 15 is provided, but the second corrosion prevention layer 15 has an arbitrary structure in the present invention.

< second adhesive layer 16 >

The second adhesive layer 16 may have the same structure as the first adhesive layer 12, or may be a layer made of an adhesive such as a general polyurethane adhesive or epoxy adhesive. The thickness of the second adhesive layer 16 can be set to 0.5 to 10 μm, for example. By setting the thickness in this range, the second base material layer 17 and the metal foil 14 can be bonded with high adhesion, and delamination can be prevented. In this embodiment, the second adhesive layer 16 is provided, but the second adhesive layer 16 has an arbitrary configuration in the present invention.

< second substrate layer 17 >

The second base material layer 17 is not particularly limited as long as it has sufficient mechanical strength, and for example, polyester resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT); polyamide resins such as nylon (Ny); polyolefin resins such as stretched polypropylene (OPP); synthetic resin films made of polyether ether ketone (PEEK), polyphenylene sulfide (PPS), and the like. Among them, a PET film is preferable.

The thickness of the second substrate layer 17 may be, for example, 1 to 50 μm, preferably 1 to 30 μm, and more preferably 3 to 11 μm.

The second substrate layer 17 may have a single-layer structure or a multilayer structure. An example of the second substrate layer 17 having a multilayer structure is a two-layer film in which a polyethylene terephthalate (PET) resin film is laminated on a biaxially stretched polyamide resin film (ONy). The second base material layer 17 may have a multilayer structure in which 3 or more films are laminated.

In the embodiment shown in fig. 1, the second base material layer 17 is an outermost layer. Therefore, the second base material layer can have a desired color or design by containing a coloring material such as a pigment other than the resin.

The second substrate layer 17 is preferably formed of a single-layer or multi-layer film using a heat-resistant resin film having a melting point of 200 ℃. Examples of such a heat-resistant resin film include a PET film, a PEN film, a PBT film, a nylon film, a PEEK film, and a PPS film, but a 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 packaging laminate 10 can be improved, and the durability of a battery using the battery exterior packaging laminate 10 can be improved. In this embodiment, the second base material layer 17 is provided, but the second base material layer 17 has an arbitrary configuration in the present invention.

In the battery exterior package laminate 10 shown in fig. 1, the first corrosion prevention layer 13 and the second corrosion prevention layer 15 are formed on both sides of the metal foil 14, but in the battery exterior package using the battery exterior package laminate 10, the first base material layer 11 is provided on the inner surface side and is contactable with an 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 metal foil 14. That is, the second corrosion prevention layer 15, the second adhesive layer 16, and the second base material layer 17 (particularly, the second corrosion prevention layer 15 and the second adhesive layer 16) may be omitted from the laminate 10 for battery exterior packaging of fig. 1.

In the laminate 10 for battery exterior packaging shown in fig. 1, the second base material layer 17 is used as the outermost layer, but the outermost layer may be formed of a coating layer on the outer surface side of the second base material layer 17, or the outermost layer may be formed of a coating layer without providing the second corrosion prevention layers 15 to 17.

The coating layer (first coating layer) is formed of at least one resin selected from the group consisting of a polyurethane resin, an acrylic resin, polyvinylidene chloride, a vinylidene chloride-vinyl chloride copolymer resin, a maleic anhydride-modified polypropylene resin, a polyester resin, an epoxy resin, a phenol resin, a phenoxy resin, a fluorine resin, a cellulose ester resin, a cellulose ether resin, a polyamide resin, a polyphenylene ether resin (PPE), a polyphenylene sulfide resin (PPS), a polyarylether resin (PAE), and a polyetheretherketone resin (PEEK). The coating layer is preferably made of a material having excellent heat resistance. These resins may be used singly or in combination of two or more.

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

By forming the coating layer, the insulation properties of the battery exterior laminate 10 can be improved, and damage to the surface of the battery exterior laminate 10 can be prevented. Further, the battery exterior laminate 10 can prevent changes in appearance (discoloration and the like) even when it comes into contact with the electrolyte solution.

Further, the coating layer can be colored by adding a colorant or a pigment to the solvent-based paint for forming the coating layer. In addition, the coating layer may be colored or printed to improve design properties in order to represent characters, graphics, images, patterns, and the like.

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

In the laminate 10 for battery exterior packaging shown in fig. 1, the second base material layer 17 and the second adhesive layer 16 are in direct contact, but a printed layer for improving design may be provided on the inner surface side of the second base material layer 17.

The printed layer may be provided in the same structure as the above-described coating layer.

The thickness of the laminate 10 for battery outer packaging is preferably 10 to 200 μm, more preferably 20 to 100 μm, and still more preferably 30 to 80 μm.

Examples of the battery using the laminate 10 for battery exterior packaging include secondary batteries such as lithium ion batteries as secondary batteries, and batteries using an organic electrolyte as an electrolyte solution, such as capacitors such as electric double layer capacitors. The organic electrolyte is usually a medium of carbonates such as Propylene Carbonate (PC), diethyl carbonate (DEC), and ethylene carbonate, but is not particularly limited thereto.

The laminate for battery exterior packaging of the present invention can be produced, for example, by a method comprising the steps of: forming a first anti-corrosion layer 13 on one surface of the metal foil 14; a step of forming a first adhesive layer 12 on the formed first anti-corrosion layer 13; and a step of laminating the laminate by placing the first base material layer 11 in contact with the formed first adhesive layer 12.

The details will be described below.

First, the first corrosion prevention layer 13 is formed on one surface of the metal foil 14.

Specifically, the corrosion-preventing treatment agent is applied to the surface of the metal foil 14 and then heated and dried. In this case, only the first corrosion prevention layer 13 may be formed by applying the corrosion prevention treatment agent to only one surface of the metal foil 14, or the second corrosion prevention layer 15 may be formed simultaneously by applying the corrosion prevention treatment agent to both surfaces of the metal foil 14. When the second corrosion prevention layer 15 is provided, the second corrosion prevention layer 15 is preferably formed at a stage before the first adhesive layer 12 and the like are formed, and more preferably formed simultaneously with the first corrosion prevention layer 13.

When the first corrosion-prevention layer 13 and the second corrosion-prevention layer 15 are formed simultaneously, it is also preferable that the metal foil 14 is immersed in a corrosion-prevention treatment agent, the corrosion-prevention treatment agent is attached to both surfaces of the metal foil 14, and then the metal foil is heated and dried.

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

Specifically, a layer made of the adhesive is formed on the surface of the metal foil 14 on which the first corrosion prevention layer 13 is provided, and is heated and dried as necessary.

When the adhesive is an adhesive for thermal lamination containing no organic solvent, the component (a) and the component (B) are melt kneaded to react the two components, and then the first adhesive layer 12 is formed by applying and drying the first corrosion-resistant layer 13.

The melt kneading may be carried out by a known apparatus such as a single-screw extruder, a multi-screw extruder, a Banbury mixer (Bunbury mixer), a plastic mixer (Plastmill), or a heated roll kneader. In order to suppress the decomposition of the epoxy group at the time of melt kneading, it is preferable that volatile components such as water which can react with the epoxy group are removed in advance from the apparatus, and when volatile components are generated during the reaction, they are discharged to the outside of the apparatus at any time by deaeration or the like. The acid-modified polyolefin resin having an acid anhydride group as an acidic functional group is preferable because it has high reactivity with an epoxy group and can be reacted under milder conditions. The heating temperature at the time of melt kneading is preferably selected from the range of 240 to 300 ℃ from the viewpoint that both components are sufficiently melted and thermal decomposition is not caused. Further, the kneading temperature can be measured by a method of contacting a thermocouple with the adhesive in a molten state immediately after extrusion from the melt kneading apparatus, or the like.

When the adhesive is an adhesive for dry lamination containing an organic solvent, the first adhesive layer 12 is formed by dissolving the components (a) and (B) in the organic solvent, applying the solution on the first corrosion-resistant layer 13, and drying. The first adhesive layer 12 may be formed in a series of steps using a known dry laminating machine or the like in addition to the step of laminating with the first base material layer 11 described later.

Then, the laminate is laminated so that the first base material layer 11 is in contact with the formed first adhesive layer 12. The lamination may be dry lamination or thermal lamination, but is preferably dry lamination at 70 to 150 ℃. 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, and the film is provided on the first adhesive layer and then laminated. The temperature for lamination 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 metal foil 14 can be satisfactorily bonded via the first adhesive layer, and it can be determined in consideration of the material and melting point of the adhesive constituting the first adhesive layer 12. The temperature for dry lamination is usually 70 to 150 ℃ and preferably 80 to 120 ℃.

Since the laminate for battery exterior packaging of the present embodiment has a structure in which the first base material layer 11, the first corrosion prevention layer 13, and the metal foil 14 are bonded via the first adhesive layer 12, the above-described dry lamination can be employed also in the bonding. By using dry lamination as necessary, the temperature at the time of lamination can be greatly reduced.

Generally, when high heat is applied to a metal foil having low thermal conductivity and being less likely to expand, the metal foil is likely to warp (curl) in the width direction. When the metal foil is used for thermal lamination, heat cannot sufficiently spread in the plane, and a portion not in contact with a hot press roller may be generated in the width direction, or the metal foil may not be in contact with the roller, and a crack or a wrinkle may be generated at the time of hot pressing due to warpage itself. Further, when the metal foil is heated to a high temperature at which the metal foil is not warped, the production efficiency is low due to a reduction in the processing speed and an increase in the required amount of heat. Further, by lowering the temperature at the time of lamination, whitening or the like due to heat of the first base material layer 11 can be prevented, deterioration of the first base material layer 11 can be prevented, and the selection range of the first base material layer 11 can be widened.

In addition, when dry lamination is employed in the production of the laminate for battery exterior packaging of the present embodiment, the occurrence of cracks, wrinkles, whitening of the resin, and the like can be suppressed, and a suitable laminate for battery exterior packaging can be produced with high production efficiency.

The step of forming the first adhesive layer 12 and the step of providing the first base material layer 11 and performing (dry) lamination may be performed in a series of steps using a known (dry) lamination apparatus.

The method for forming the second anticorrosive layer 15, the second adhesive layer 16, and the second base material layer 17 is not particularly limited, but for example, the second adhesive layer 16 may be formed on the second base material layer 17 in advance to form a laminate composed of two layers. The battery exterior packaging laminate 10 having seven layers can be prepared by dry-laminating the two-layer laminate and a laminate having the first base material layer 11, the first adhesive layer 12, the first corrosion-resistant layer 13, the metal foil 14, and the second corrosion-resistant layer 15 so that the second adhesive layer 16 and the second corrosion-resistant layer 15 are in contact with each other.

While one embodiment of the present invention has been described above with reference to the laminate 10 for battery exterior packaging shown in fig. 1, the technical scope of the present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the scope of the present invention.

For example, the second corrosion prevention layer 15 may not be provided, and six layers may be provided. The second corrosion prevention layer 15, the second adhesive layer 16, and the second base material layer 17 may not be provided, and a four-layer structure may be provided, or the first corrosion prevention layer 13, the second corrosion prevention layer 15, the second adhesive layer 16, and the second base material layer 17 may not be provided, and a three-layer structure may be provided.

Further, another layer may be provided on the side of the first base material layer 11 not in contact with the first adhesive layer 12 or on the side of the second base material layer 17 not in contact with the second adhesive layer 16, and the structure may be seven or eight or more layers.

[ Battery outer packaging body ]

A battery exterior package according to a second aspect of the present invention is a battery exterior package including the laminate for battery exterior packaging of the first aspect, and has an internal space for housing a battery, the internal space being on the side of the first base layer of the laminate for battery exterior packaging. Specifically, the laminate for battery exterior packaging of the first aspect is molded into a desired shape so that the first base material layer faces the internal space, and is obtained by sealing the end portions or the like as necessary.

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

The battery exterior body may be formed of one member, or may be formed by combining two or more members (for example, a container body and a lid) as will be described later with reference to fig. 2.

[ Battery ]

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

Examples of the battery include secondary batteries such as lithium ion batteries as secondary batteries, capacitors such as electric double layer capacitors, and batteries using an organic electrolyte as an electrolytic solution. The laminate for battery exterior packaging of the present invention has high electrolyte resistance, and therefore contains LiPF even when used₆And the like, a battery that can operate suitably can be obtained.

As an example, a perspective view of the secondary battery 40 is shown in fig. 2. The secondary battery 40 includes a lithium ion battery 27 in the battery outer casing 20.

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

The battery shown in fig. 2 may be prepared in the following manner.

First, as shown in fig. 3 (a), the battery exterior packaging laminate 10 is formed into a disk shape having the recess 31 by drawing or the like to obtain the container body 30. The depth of the recess 31 may be 2mm or more, for example.

A lithium ion battery (lithium ion battery 27 in fig. 2) is housed in the recess 31 of the container main body 30.

Then, as shown in fig. 3 (b), the lid 33 composed of the cell exterior laminate 10 is superimposed on the container main body 30, and the flange portion 32 of the container main body 30 and the peripheral edge portion 34 of the lid 33 are heat-sealed to obtain the secondary cell 40 shown in fig. 2. That is, in the battery shown in fig. 3, by covering the lid portion 33 on the upper surface of the container main body 30, an internal space for housing the battery is formed by the recess 31 and the lid portion 33.

Examples

The present invention will be described in further detail with reference to examples, but the present invention is not limited to these examples.

Examples 1 to 15 and comparative examples 1 to 13

< examples 1 to 15, comparative examples 1 to 3, and 5 >

First, the metal foils shown in table 1 were prepared. Both surfaces of the metal foil were coated with an anti-corrosion treatment agent shown in Table 1 (coating weight: 12 g/m)²) The coating was dried by heating in an oven at 200 ℃ to form a first anticorrosive layer and a second anticorrosive layer each having a thickness of 0.2 μm on both surfaces.

Thereafter, a first adhesive was applied to the first corrosion-prevention layer to form a first adhesive layer having a thickness of 3 μm. The first adhesive is obtained by mixing a solution obtained by dissolving the component (a) shown in table 1 in toluene as an organic solvent and a solution obtained by dissolving the component (B) shown in table 1 in methyl ethyl ketone as an organic solvent. The parts by mass of each component in table 1 are the final blending amounts after mixing. The solvent amount of the solution was adjusted so that the final solid content was 9 mass% in the binder. The final mixing ratio (mass ratio) of methyl ethyl ketone to toluene was 1: 1.

The first adhesive layer of the laminate containing the metal foil and the first base material layer composed of a polypropylene resin (block PP) film having a thickness of 20 μm were laminated by dry lamination at 100 ℃.

A second adhesive layer made of a polyurethane adhesive was formed by coating on a second base material layer made of a black stretched polyethylene terephthalate (PET) resin film having a thickness of 6 μm (thickness of 3 μm).

The second adhesive layer was laminated on the second anti-corrosion layer in the laminate obtained above at 80 ℃ by dry lamination to obtain a laminate for battery exterior packaging.

< comparative example 4 >

A battery exterior laminate was obtained in the same manner as in example 1, except that the component (B) in the first adhesive was not used. The adhesive of comparative example 4 was obtained by mixing a toluene solution in which the component (a) was dissolved with methyl ethyl ketone in which the component (B) was not dissolved.

[ Table 1]

In table 1, the abbreviations each have the following meanings. [] The numerical value in (b) is the blending amount (parts by mass).

(A) -1: maleic anhydride-modified Polypropylene (melting point 85 ℃ C.)

(A) -2: maleic anhydride-modified 1-butene-propylene copolymer (melting point 80 ℃ C.)

(B) -1: "jER 154" (trade name; manufactured by Mitsubishi chemical corporation; novolac epoxy resin; viscosity 80; epoxy equivalent 180)

(B) -2: 50/50 (mass ratio) of "JeR 154" and "D-17" (trade name; manufactured by Mitsui chemical Co., Ltd.; isocyanate Compound)

(B) -3: "jER 157S 70" (trade name; manufactured by Mitsubishi chemical corporation; novolac epoxy resin having a bisphenol A structure; viscosity 80; epoxy equivalent 210)

(B) -4: phenoxy resin having no epoxy group and having ring-opened terminal epoxy group

(B)-5：“D-17”

(C) -1: toluene/methyl ethyl ketone 80/20 (mass ratio) mixed solvent

AL: aluminum foil

SUS: stainless steel foil

CO: copper foil

NI: nickel foil

R-1: an aqueous solution obtained by dissolving 0.2 mass% of a hydroxyl group-containing non-crystalline polymer having a polyvinyl alcohol skeleton and a saponification degree of 95 mol% (JAPAN VAM & POVAL CO., LTD., product name: AP-17; (PVA-1)), 0.8 mass% of ferric chloride, and 0.7 mass% of an oxazoline resin (product name: WS-500, manufactured by Nippon catalyst Co., Ltd.) in water.

R-2: an aqueous solution similar to that of R-1 except that ferric chloride was changed to chromium fluoride

R-3: an aqueous solution similar to that of R-1 except that ferric chloride was changed to ferric oxide

(storage modulus measurement)

The dynamic viscoelasticity of the first adhesive layer single layer was measured in accordance with JIS K7244 "test method for plastic-dynamic mechanical properties".

Specifically, the first adhesive of each example shown above was first applied to a fluororesin substrate, heated at 110 ℃ for 300 seconds to completely volatilize the organic solvent, and then cured at 80 ℃ for 3 days to completely crosslink the first adhesive. Then, the substrate was peeled off to obtain a single-layer adhesive layer having a thickness of 0.3mm, a width of 4mm and a length of 30 mm. The obtained single-layer adhesive layer was placed on a dynamic viscoelasticity measuring apparatus having a chuck pitch of 20mm, and the value of the storage modulus (E') at 150 ℃ when the frequency of application was 1Hz and the strain was 0.01% under atmospheric pressure was determined. As the dynamic viscoelasticity measuring apparatus, a dynamic viscoelasticity measuring apparatus "RSA-3" (trade name) manufactured by TA Instrument Co.

The results are also shown in Table 1.

(Heat resistance test)

The laminate for battery exterior packaging prepared in each of the above examples was heat-sealed at 0.3MPa 190 ℃.3 seconds, subjected to T-peeling in an environment of 85 ℃, and evaluated according to the following criteria, and the results are shown in table 1 as "heat resistance".

Very good: 25N/15mm or more

O: less than 25N/15mm and 15N/15mm or more

X: less than 15N/15mm

(electrolyte resistance test)

An electrolyte (1 mol/L LiPF added) containing 1000ppm of water and having a temperature of 85 ℃ was prepared₆Ethylene carbonate, diethyl carbonate, dimethyl carbonate, 1:1:1 vol%) was immersed in the electrolyte solution for 3 days.

After 3 days, a 90 ° peel test was performed. The evaluation was performed according to the following criteria, and the evaluation results are shown in table 1 as "electrolyte resistance".

A: 5N/15mm or more

B: less than 5N/15mm and more than 3N/15mm

C: less than 3N/15mm and 1N/15mm or more

D: less than 1N/15mm

From the results shown in table 1, it was confirmed that examples 1 to 15 using the laminate for outer packaging of a battery of the present invention have superior adhesiveness even under severe conditions as compared with comparative examples 1 to 5.

[ Experimental examples 1 to 3, comparative Experimental example 1]

First adhesives of the respective examples shown in table 2 were obtained in the same manner as in examples 1 to 13 and the like. The abbreviations in table 2 are the same as those described above.

Then, in the same manner as the storage modulus measurement, the storage modulus was measured while heating from 20 ℃ to 160 ℃ at a heating rate of 3 ℃/min using a dynamic viscoelasticity measuring apparatus. The results are shown in FIG. 4.

[ Table 2]

From the results shown in fig. 4, it was confirmed that the adhesive containing the component (a) and the component (B) did not decrease in storage modulus (E'; unit Pa) even at high temperature, while the adhesive containing no component (B) did significantly decrease in storage modulus at high temperature, and as a result, the shape could not be maintained.

Claims

1. A laminate for battery outer packaging comprising at least a first base material layer, a first adhesive layer and a metal foil in this order, characterized in that:

The first base material layer is a layer composed of polyolefin,

The first adhesive layer is a layer composed of an adhesive containing 70 to 99.5 parts by mass of the acid-modified polyolefin resin (A) and 0.5 to 30 parts by mass in the solid content of the adhesive. parts by mass of novolac epoxy resin (B),

The first adhesive layer has a value of storage modulus at 150° C. in the dynamic viscoelasticity measurement of the first adhesive layer single layer of 1.0×10 ⁴ or more and 1.0×10 ⁷ or less layer,

The novolak epoxy resin (B) is a bisphenol A novolak epoxy resin represented by the following general formula (1),

In formula (1), R ¹ to R ⁶ are each independently a hydrogen atom or a methyl group, n is an integer of 0 to 10, and R ^X is a glycidyl group.

2 . The laminate for battery outer packaging according to claim 1 , further comprising a first anticorrosion layer between the first adhesive layer and the metal foil, 2 .

The first anti-corrosion layer contains a halogenated metal compound.

3 . The laminate for battery outer packaging according to claim 2 , wherein the first anticorrosion layer further contains a water-soluble resin, a chelating agent, or a crosslinkable compound. 4 .

4 . The laminate for battery exterior packaging according to claim 2 , wherein the halogenated metal compound is chloride of iron, chromium, manganese, and zirconium, or fluoride of iron, chromium, manganese, and zirconium. 5 .

5 . The laminate for battery outer packaging according to claim 1 , wherein the metal foil is aluminum, stainless steel, copper, nickel, or titanium. 6 .

6 . The laminate for battery outer packaging according to claim 1 , wherein the metal foil has a thickness of 10 to 40 μm. 7 .

7 . A battery outer package comprising the laminate for a battery outer package according to claim 1 , wherein: 8 .

This battery outer package has an inner space in which the battery is accommodated, and the side of the first base material layer of the laminate for battery outer package is the inner space side.

8 . A battery having the battery outer package according to claim 7 .