WO2018070448A1

WO2018070448A1 - Adhesive composition for electrochemical elements, electrochemical element and method for producing electrochemical element

Info

Publication number: WO2018070448A1
Application number: PCT/JP2017/036882
Authority: WO
Inventors: 園部　健矢; 慶一朗田中; 小黒　寛樹
Original assignee: 日本ゼオン株式会社
Priority date: 2016-10-14
Filing date: 2017-10-11
Publication date: 2018-04-19
Also published as: JPWO2018070448A1; JP6996513B2; KR20190062425A; KR20220110610A; KR102474504B1

Abstract

An adhesive composition for electrochemical elements, which contains: a polymer that has one or more functional groups selected from among a carboxylic acid group, a hydroxyl group, an amino group, an epoxy group, an oxazoline group, an isocyanate group and a sulfonic acid group; and an organic solvent.

Description

Adhesive composition for electrochemical element, electrochemical element, and method for producing electrochemical element

The present invention relates to an adhesive composition for an electrochemical element, an electrochemical element, and a method for producing an electrochemical element.

Electrochemical elements such as lithium ion secondary batteries, electric double layer capacitors, and lithium ion capacitors are small and lightweight, have high energy density, and can be repeatedly charged and discharged, and are used in a wide range of applications. Yes. The electrochemical element generally includes an exterior body and an electrode assembly accommodated in the exterior body. The electrode assembly is a laminated body of a plurality of electrodes and a separator that isolates these electrodes to prevent a short circuit.

Conventionally, in order to ensure the safety and the like of such an electrochemical element, a technique for adhering an electrode assembly and an exterior body in the electrochemical element and fixing the electrode assembly to the exterior body has been studied (for example, patents). Reference 1). In Patent Document 1, a secondary battery sealing tape comprising a first adhesive layer having an adhesive surface and a second adhesive layer having an adhesive surface opposite to the adhesive surface of the first adhesive layer. By adhering the adhesive surface of the first adhesive layer to the outer surface of the electrode assembly and adhering the adhesive surface of the second adhesive layer to the inner surface of the exterior body, the electrode assembly moves inside the exterior body. It has been reported that it can prevent and improve the safety of secondary batteries.

Moreover, the adhesive composition for electrochemical elements which can form the adhesive layer for electrochemical elements which can maintain the outstanding adhesiveness in electrolyte solution and can exhibit the electrical property excellent in the electrochemical element conventionally Has been proposed (see, for example, Patent Document 2). In Patent Document 2, an exterior body and an electrode assembly are bonded using an adhesive composition in which organic particles having a specific core-shell structure are dispersed in water.

Special table 2012-529753 gazette International Publication No. 2016/051674

However, in the tape as described in Patent Document 1 and the adhesive composition as described in Patent Document 2, the adhesive strength between the outer package and the electrode assembly is increased, and the electrical property of the electrochemical element is increased. There was room for improvement in terms of improving characteristics (high temperature cycle characteristics and low temperature output characteristics).

Therefore, the present invention is an adhesive composition for an electrochemical element used for bonding an electrode assembly and an exterior body, the adhesive strength between the exterior body and the electrode assembly, and the electrical characteristics of the electrochemical element It is an object of the present invention to provide an adhesive composition for an electrochemical device that can enhance both of the above.
Another object of the present invention is to provide an electrochemical device having excellent electrical characteristics and a method for producing such an electrochemical device.

The present inventor has intensively studied for the purpose of solving the above problems. Then, the present inventor uses an adhesive composition containing a polymer having a specific functional group and an organic solvent to bond the electrode assembly and the exterior body, thereby providing an adhesive strength between the electrode assembly and the exterior body. In addition, the inventors have found that the electrochemical element can exhibit excellent electrical characteristics, and have completed the present invention.

That is, this invention aims to solve the above-mentioned problem advantageously, and the adhesive composition for an electrochemical element of the present invention is for an electrochemical element used for adhesion between an electrode assembly and an exterior body. An adhesive composition comprising a polymer and an organic solvent, wherein the polymer is any one of a carboxylic acid group, a hydroxyl group, an amino group, an epoxy group, an oxazoline group, an isocyanate group, and a sulfonic acid group. It has one or more functional groups. Thus, if the adhesive composition containing the polymer which has a specific functional group, and an organic solvent is used, an adhesive layer with high adhesive strength can be formed. Furthermore, the electrochemical element in which the electrode assembly is fixed to the exterior body using the adhesive layer is excellent in electrical characteristics.

And it is preferable that surface tension is 10 mN / m or more and 50 mN / m or less of the adhesive composition for electrochemical elements of this invention. If the surface tension of the adhesive composition is within the specific range, the adhesive strength of the resulting adhesive layer can be further increased.
Here, in the present invention, the “surface tension of the adhesive composition” can be measured according to a platinum plate method at a temperature of 25 degrees.

Furthermore, in the adhesive composition for electrochemical elements of the present invention, the outer package has a resin layer on at least the inner surface, and the solubility of the resin layer in the organic solvent is 0.001% or more and 10.000% or less. It is preferable that If the adhesive composition can dissolve the resin layer on the exterior body surface to be adhered to some extent, the adhesive strength can be further increased.
Here, in the present invention, “the solubility of the resin in the organic solvent” can be measured by the method described in the examples.

Furthermore, in the adhesive composition for electrochemical devices of the present invention, the polymer preferably has a glass transition temperature of −100 ° C. or higher and 50 ° C. or lower. If the glass transition temperature of the polymer contained in the adhesive composition is within the above specified range, the adhesive strength of the resulting adhesive layer is further enhanced, and the electrical characteristics of the electrochemical device having such an adhesive layer are further enhanced. Can do.
Here, in the present invention, the “glass transition temperature of the polymer” can be measured by the method described in Examples.

Furthermore, in the adhesive composition for electrochemical elements of the present invention, the degree of swelling of the electrolyte solution of the polymer is preferably 1 to 10 times. If the electrolyte solution swelling degree of the polymer contained in the adhesive composition is within the specific range, the electrical characteristics of the electrochemical element formed using the adhesive composition can be further improved.
Here, in the present invention, “the degree of swelling of the electrolyte of the polymer” can be measured by the method described in the examples.

Furthermore, the adhesive composition for electrochemical devices of the present invention preferably further contains an amine compound. If the adhesive composition contains an amine compound, the adhesive strength of the resulting adhesive layer can be further increased.

Moreover, this invention aims at solving the said subject advantageously, The electrochemical element of this invention is an electrochemical element provided with an exterior body and the electrode assembly accommodated in this exterior body. The exterior body has a resin layer on the inner surface, and is formed by using any of the above-described adhesive compositions for electrochemical elements between the resin layer and the electrode assembly. It has an adhesive layer for elements. If the adhesive layer formed using the adhesive composition of the present invention is disposed between the resin layer on the surface of the exterior body and the electrode assembly, the electrical characteristics of the electrochemical device can be enhanced.

Furthermore, in the electrochemical element of the present invention, it is preferable that the resin layer of the outer package is a thermoplastic resin layer. This is because if the thermoplastic resin layer is formed on the surface of the exterior body, the adhesive strength between the exterior body and the electrode assembly can be further improved, and the electrical characteristics of the electrochemical element can be further enhanced.

Moreover, this invention aims at solving the said subject advantageously, The electrochemical element manufacturing method of this invention apply | coats any adhesive composition for electrochemical elements mentioned above, and applies. A coating process for obtaining a coating film, a drying process for drying the coating film to obtain an adhesive layer for electrochemical elements, and an adhesion for bonding the electrode assembly and the exterior body via the adhesive layer for electrochemical elements And any one of the above-described electrochemical elements is manufactured through a process. If an electrochemical element is manufactured using the specific adhesive composition described above, an electrochemical element having excellent electrical characteristics can be manufactured satisfactorily.

Furthermore, in the electrochemical element manufacturing method of the present invention, the solubility of the resin layer of the outer package in the organic solvent is preferably 0.001% or more and 10.000% or less. If the adhesive composition can dissolve the resin layer on the exterior body surface to be adhered to some extent, the adhesive strength between the exterior body and the electrode assembly can be further improved, and the electrical characteristics of the electrochemical device can be improved. This is because it can be further improved.
In addition, "the solubility with respect to the organic solvent of the resin layer of an exterior body" can be measured by the method as described in the Example of this specification.

According to the present invention, there is provided an adhesive composition for an electrochemical device used for bonding an electrode assembly and an exterior body, the adhesive strength between the exterior body and the electrode assembly, and the electrical characteristics of the electrochemical device. It is possible to provide an adhesive composition for an electrochemical device that can increase both of the above.
Moreover, according to this invention, the electrochemical element which is excellent in an electrical property, and the manufacturing method of this electrochemical element can be provided.

Hereinafter, embodiments of the present invention will be described in detail.
Here, the adhesive composition for an electrochemical element of the present invention is used as an adhesive layer for an electrochemical element by drying or the like, and is used for bonding an electrode assembly and an exterior body in the electrochemical element. The electrochemical element of the present invention includes an electrochemical element adhesive layer formed using the adhesive composition of the present invention between the electrode assembly and the exterior body, and the electrochemical element adhesive layer is interposed therebetween. The electrode assembly and the exterior body are bonded together. In addition, the electrochemical device of the present invention can be manufactured according to the electrochemical device manufacturing method of the present invention.

(Adhesive composition for electrochemical devices)
The adhesive composition for electrochemical devices is a slurry composition containing a polymer having a specific functional group and an organic solvent. And the adhesive layer for electrochemical elements formed using the adhesive composition for electrochemical elements of this invention can raise the adhesive strength between an electrode assembly and the exterior body containing this electrode assembly. In addition, an electrochemical element in which the electrode assembly and the outer package are fixed to each other via the adhesive layer is excellent in electrical characteristics such as high temperature cycle characteristics and low temperature output characteristics.

<Polymer>
The polymer has a function of firmly bonding the electrode assembly and the exterior body in the adhesive layer obtained using the adhesive composition. Such a polymer has one or more functional groups of a carboxylic acid group, a hydroxyl group, an amino group, an epoxy group, an oxazoline group, an isocyanate group, and a sulfonic acid group. Furthermore, the polymer preferably has at least one of a carboxylic acid group, a hydroxyl group, an amino group, an epoxy group, an oxazoline group, and a sulfonic acid group, and the carboxylic acid group, hydroxyl group, amino group, epoxy group And at least one of sulfonic acid groups, more preferably at least one of carboxylic acid groups, sulfonic acid groups, hydroxyl groups, and epoxy groups, and carboxylic acid groups and It is particularly preferable to have an epoxy group. This is because the adhesive strength that can be exhibited by the adhesive layer obtained using the adhesive composition can be further improved.
In addition, the polymer which has the said specific functional group can also use multiple types together.

Here, in the adhesive composition for an electrochemical element of the present invention, by using a polymer having at least one of the specific functional groups and an organic solvent in combination, the adhesive force and the electrochemical properties of the adhesive layer The reason why the electrical performance of the device can be remarkably improved is not clear, but is presumed to be as follows. That is, first, the above-mentioned specific functional group that can be contained in the polymer acts so as to remarkably improve the adhesive force of the obtained adhesive layer in combination with the organic solvent, thereby improving the adhesive force of the adhesive layer itself. To do. Here, if the adhesive strength of the adhesive layer itself is weak and the adhesive strength between the electrode assembly and the exterior body is insufficient, it occurs in the electrochemical element due to a chemical reaction accompanying the use of the electrochemical element. The gas may damage the adhesion between the electrode assembly and the outer package, resulting in deterioration of electrical characteristics. Therefore, it is presumed that deterioration of the electrical characteristics of the electrochemical element can be suppressed by using an adhesive layer with high adhesive strength obtained by the present invention.

In addition, it is preferable that a polymer contains 1 mass% or more of monomer units containing at least one of the specific functional groups, based on 100% by mass of all monomer units in the polymer. In particular, when the polymer contains a carboxylic acid group, the polymer preferably contains 1.5% by mass or more of the carboxylic acid group-containing monomer unit, more preferably 2% by mass or more, and 20% by mass. % Or less is preferable. Moreover, when a polymer contains an epoxy group, it is preferable that a polymer contains 3 mass% or more of epoxy group-containing monomer units, more preferably 5 mass% or more, and 20 mass% or less. Is preferred. Furthermore, when the polymer contains a sulfonic acid group, the polymer preferably contains 1.5% by mass or more of the sulfonic acid group-containing monomer unit, more preferably 2% by mass or more. It is preferable to contain it by mass% or less. Furthermore, the carboxylic acid group-containing monomer unit preferably does not contain a sulfonic acid group and an epoxy group, and the epoxy group-containing monomer unit preferably does not contain a carboxylic acid group and a sulfonic acid group. The group-containing monomer unit preferably does not contain a carboxylic acid group or an epoxy group. In the present invention, “comprising a monomer unit” means “a monomer-derived structural unit is contained in a polymer obtained using the monomer”.

[Glass transition temperature of polymer]
The polymer has a glass transition temperature of preferably −100 ° C. or higher, more preferably −50 ° C. or higher, still more preferably −30 ° C. or higher, particularly preferably −20 ° C. or higher, preferably 50 ° C. or lower, more preferably 30 ° C or lower, more preferably 20 ° C or lower. If the lower limit value of the glass transition temperature of the polymer is equal to or higher than the lower limit value, the adhesive force of the resulting adhesive layer is further improved, and electrical properties such as high temperature cycle characteristics and low temperature output characteristics of an electrochemical device comprising such an adhesive layer are provided. Characteristics can also be improved. Moreover, if the upper limit of the glass transition temperature of a polymer is below the said upper limit, the adhesive force of the adhesive layer obtained can be improved further.

[Polymer swelling degree of polymer]
The polymer has a degree of swelling of the electrolyte of 1 or more, preferably more than 1 time, more preferably 2 times or more, preferably 10 times or less, more preferably 8 times or less, still more preferably 7 times or less, particularly preferably. Is 6 times or less. By setting the degree of swelling of the electrolytic solution of the polymer within the above range, the electrical characteristics of the electrochemical device including the obtained adhesive layer can be further improved.

[Method for preparing polymer]
The polymer having the specific functional group can be obtained, for example, by polymerizing by a general polymerization method using a monomer containing at least one functional group among the specific functional groups. The polymerization method is not particularly limited, and any method such as a solution polymerization method, a suspension polymerization method, a bulk polymerization method, and an emulsion polymerization method can be used. As the polymerization method, any method such as ionic polymerization, radical polymerization, and living radical polymerization can be used. From the viewpoint of production efficiency, the emulsion polymerization method is particularly preferable. Emulsion polymerization can be performed according to a conventional method.

And generally used emulsifiers, dispersants, polymerization initiators, polymerization aids and the like used for polymerization can be used, and the amount used is also generally used. In the polymerization, seed polymerization may be performed using seed particles. The polymerization conditions can also be arbitrarily selected depending on the polymerization method and the type of polymerization initiator.

As the monomer used for preparing the polymer, a monomer containing at least one of the specific functional groups described above can be appropriately selected and used.

-Monomers containing specific functional groups-
Examples of the carboxylic acid group-containing monomer include monocarboxylic acids and derivatives thereof, dicarboxylic acids and acid anhydrides, and derivatives thereof.
Examples of monocarboxylic acids include acrylic acid, methacrylic acid, and crotonic acid.
Examples of monocarboxylic acid derivatives include 2-ethylacrylic acid, isocrotonic acid, α-acetoxyacrylic acid, β-trans-aryloxyacrylic acid, α-chloro-β-E-methoxyacrylic acid and the like.
Examples of the dicarboxylic acid include maleic acid, fumaric acid, itaconic acid and the like.
Dicarboxylic acid derivatives include methylmaleic acid, dimethylmaleic acid, phenylmaleic acid, chloromaleic acid, dichloromaleic acid, fluoromaleic acid, nonyl maleate, decyl maleate, dodecyl maleate, octadecyl maleate, fluoro maleate And maleic acid monoesters such as alkyl.
Examples of the acid anhydride of dicarboxylic acid include maleic anhydride, acrylic anhydride, methyl maleic anhydride, and dimethyl maleic anhydride.
Moreover, as a carboxylic acid group containing monomer, the acid anhydride which produces | generates a carboxyl group by hydrolysis can also be used.
Among these carboxylic acid group-containing monomers, methacrylic acid is preferable.

Examples of the hydroxyl group-containing monomer include ethylenically unsaturated alcohols such as (meth) allyl alcohol, 3-buten-1-ol, 5-hexen-1-ol; 2-hydroxyethyl acrylate, acrylic acid-2 Ethylenic acid such as hydroxypropyl, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, di-2-hydroxyethyl maleate, di-4-hydroxybutyl maleate, di-2-hydroxypropyl itaconate Alkanol esters of unsaturated carboxylic acids; general formula: CH ₂ ═CR ¹ —COO— (C _q H _2q O) _p —H (wherein p is an integer from 2 to 9, q is an integer from 2 to 4, esters R ¹ is a polyalkylene glycol and (meth) acrylic acid represented by hydrogen or a methyl group); 2-hydroxyethyl Mono (meth) acrylic acid esters of dihydroxy esters of dicarboxylic acids such as -2 '-(meth) acryloyloxyphthalate, 2-hydroxyethyl-2'-(meth) acryloyloxysuccinate; 2-hydroxyethyl vinyl ether, 2 Vinyl ethers such as hydroxypropyl vinyl ether; (meth) allyl-2-hydroxyethyl ether, (meth) allyl-2-hydroxypropyl ether, (meth) allyl-3-hydroxypropyl ether, (meth) allyl-2-hydroxy Mono (meth) allyl ethers of alkylene glycols such as butyl ether, (meth) allyl-3-hydroxybutyl ether, (meth) allyl-4-hydroxybutyl ether, (meth) allyl-6-hydroxyhexyl ether; Polyoxyalkylene glycol mono (meth) allyl ethers such as diethylene glycol mono (meth) allyl ether and dipropylene glycol mono (meth) allyl ether; glycerin mono (meth) allyl ether, (meth) allyl-2-chloro-3- Mono (meth) allyl ethers of halogens and hydroxy-substituted products of (poly) alkylene glycols, such as hydroxypropyl ether, (meth) allyl-2-hydroxy-3-chloropropyl ether; polyphenols such as eugenol, isoeugenol Mono (meth) allyl ether and its halogen-substituted product; (meth) allylthioether of alkylene glycol such as (meth) allyl-2-hydroxyethylthioether, (meth) allyl-2-hydroxypropylthioether Le acids; and the like.
In the present invention, “(meth) allyl” means allyl and / or methallyl, and “(meth) acryloyl” means acryloyl and / or methacryloyl.

Examples of amino group-containing monomers include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, aminoethyl vinyl ether, dimethylaminoethyl vinyl ether, and the like. In the present invention, “(meth) acrylate” means acrylate and / or methacrylate.

Examples of the epoxy group-containing monomer include monomers containing a carbon-carbon double bond and an epoxy group.
Examples of the monomer containing a carbon-carbon double bond and an epoxy group include unsaturated glycidyl ethers such as vinyl glycidyl ether, allyl glycidyl ether, butenyl glycidyl ether, o-allylphenyl glycidyl ether; butadiene monoepoxide, Diene or polyene monoepoxides such as chloroprene monoepoxide, 4,5-epoxy-2-pentene, 3,4-epoxy-1-vinylcyclohexene, 1,2-epoxy-5,9-cyclododecadiene; Alkenyl epoxides such as epoxy-1-butene, 1,2-epoxy-5-hexene, 1,2-epoxy-9-decene; glycidyl acrylate, glycidyl methacrylate, glycidyl crotonate, glycidyl-4-heptenoate, glycidyl Glycidyl esters of unsaturated carboxylic acids such as rubetate, glycidyl linoleate, glycidyl-4-methyl-3-pentenoate, glycidyl ester of 3-cyclohexene carboxylic acid, glycidyl ester of 4-methyl-3-cyclohexene carboxylic acid; Is mentioned.
Among these epoxy group-containing monomers, allyl glycidyl ether is preferable.

Examples of the oxazoline group-containing monomer include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, Examples include 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline.

Isocyanate group-containing monomers include vinyl isocyanate, 2-isocyanatoethyl methacrylate, 2-isocyanatoethyl acrylate, 1,1- (bisacryloyloxymethyl) ethyl isocyanate, 2-isocyanatoethyl acrylate, etc. Examples include 2-[(3,5-dimethylpyrazolyl) carbonylamino] ethyl methacrylate, 2- (0- [1′-methylpropylideneamino] carboxyamino) ethyl methacrylate, which decomposes by heat to generate an isocyanate group. It is done.

Examples of sulfonic acid group-containing monomers include vinyl sulfonic acid, methyl vinyl sulfonic acid, (meth) allyl sulfonic acid, styrene sulfonic acid, (meth) acrylic acid-2-ethyl sulfonate, 2-acrylamido-2-methylpropane. Examples thereof include sulfonic acid and 3-allyloxy-2-hydroxypropanesulfonic acid. Of these sulfonic acid group-containing monomers, 2-acrylamido-2-methylpropanesulfonic acid is preferred.

-Other monomers-
In the preparation of the polymer, the monomer other than the monomer containing the specific functional group described above is not particularly limited, and examples thereof include (meth) acrylic acid such as ethyl acrylate and butyl acrylate. An ester monomer; a nitrile group-containing monomer such as acrylonitrile; an aromatic vinyl monomer such as styrene; an amide group-containing monomer such as acrylamide can be used.
In addition, it is preferable that the content rate of another monomer is 1 to 99 mass% with respect to a polymer.

<Organic solvent>
The organic solvent is not particularly limited, and any organic solvent that can dissolve the polymer can be used. For example, the organic solvents include acetonitrile, N-methyl-2-pyrrolidone, tetrahydrofuran, acetone, acetylpyridine, cyclopentanone, dimethylformamide, dimethylsulfoxide, methylformamide, methyl ethyl ketone, furfural, ethylenediamine, dimethylbenzene (xylene), methyl Benzene (toluene), cyclopentyl methyl ether, isopropyl alcohol, and the like can be used. These can be used individually by 1 type or in mixture of multiple types by arbitrary mixing ratios. Among these, as the organic solvent, it is preferable to use any one of N-methyl-2-pyrrolidone, methylbenzene, cyclopentylmethyl ether, tetrahydrofuran, acetone, dimethylformamide, methylformamide, ethylenediamine, and isopropyl alcohol. Further, as described later, since it is possible to bring an amine compound into the adhesive composition, the organic solvent contains amino groups such as N-methyl-2-pyrrolidone, dimethylformamide, methylformamide, and ethylenediamine. Particularly preferred are organic solvents.

<Amine compound>
The adhesive composition of the present invention preferably contains an amine compound in addition to the polymer and the organic solvent described above. This is because if the adhesive composition contains an amine compound, the adhesive strength of the adhesive layer formed using the adhesive composition can be further improved. The reason is not clear, but when the adhesive composition is applied on the resin layer on the exterior body surface, the amine compound in the adhesive composition improves the adhesive strength between the polymer and the resin layer. It is inferred that this is to act.

Here, the amine compound means a compound containing an amino group. Examples of amine compounds that can be contained in the adhesive composition of the present invention include aliphatic amines such as methylamine and ethylamine; and aromatic amines such as aniline. Furthermore, the amine compound is preferably a primary amine. Furthermore, the amine compound preferably has a weight average molecular weight of 1000 or less from the viewpoint of reactivity. In particular, the amine compound is preferably a so-called low molecular weight compound having a weight average molecular weight of 500 or less.

Here, when an amine compound is contained in the adhesive composition, an amine compound such as methylamine, ethylamine, or aniline can be added during the preparation of the adhesive composition. Alternatively, when an organic solvent such as N-methyl-2-pyrrolidone, which can be synthesized using an amine compound as a material, is used, the amine solvent is not added to the organic solvent without adding an amine compound. Since the compound is contained as an inevitable impurity, an amine compound can be contained in the adhesive composition.

In the adhesive composition of the present invention, the concentration of the amine compound is preferably 10 ppm or more, more preferably 20 ppm or more, more preferably 90 ppm or more, and preferably 500 ppm or less, More preferably, it is 300 ppm or less. If the density | concentration of the amine compound in an adhesive composition is in the said range, the adhesiveness of the contact bonding layer formed using the adhesive composition can be improved further. In addition, the density | concentration of the amine compound in an adhesive composition can be measured by the method described in the Example of this specification.
Furthermore, the concentration of the amine compound in the adhesive composition can be adjusted, for example, as follows. First, when an organic solvent not containing an amine compound is used as the organic solvent, the blending ratio of the amine compound to be added may be adjusted. When using an organic solvent that can contain an amine compound as an impurity during the preparation of the adhesive composition, measure the amount of the amine compound in the organic solvent, until the concentration of the amine compound reaches a desired value. The concentration of the amine compound in the adhesive composition can be adjusted by purifying the organic solvent by a conventional method.

<Other ingredients>
The adhesive composition of the present invention may optionally include, in addition to the above-described polymer and organic solvent, and any amine-based compound, another polymer having a composition and properties different from those of the above polymer, a wetting agent, and a viscosity. You may contain known additives, such as a regulator and electrolyte solution additive. These other components may be used individually by 1 type, and may be used in combination of 2 or more types. In addition, the other polymer as another component can be a polymer which does not have the said specific functional group, for example.

<Solid content concentration of adhesive composition>
The solid content concentration of the adhesive composition can usually be 1% by mass or more and 50% by mass or less from the viewpoints of coatability and adhesiveness.

<Method for preparing adhesive composition for electrochemical device>
Here, the method for preparing the adhesive composition for an electrochemical device is not particularly limited, but usually an adhesive obtained by mixing a polymer, an organic solvent, and other components that can be used as necessary. A composition is prepared. The mixing method is not particularly limited, but mixing is performed using a stirrer or a disperser that can be usually used.

The surface tension of the obtained adhesive composition is preferably 10 mN / m or more, more preferably 15 mN / m or more, further preferably 20 mN / m or more, and 25 mN / m or more. Is particularly preferably 50 mN / m or less, more preferably 47 mN / m or less, further preferably 45 mN / m or less, and particularly preferably 43 mN / m or less. If the surface tension of the adhesive composition is within the above range, the adhesiveness of the resulting adhesive layer can be further improved. In particular, when the surface tension of the adhesive composition is equal to or lower than the upper limit of the above range, it is possible to suppress coating unevenness when the adhesive composition is applied to a member to be bonded such as an electrode assembly or an exterior body. . The surface tension of the adhesive composition can be measured using the measurement method described in the examples of the present specification.
The surface tension of the adhesive composition can be appropriately adjusted by changing the amount of wetting agent or binder, for example.

(Electrochemical element)
The electrochemical device of the present invention includes an exterior body and an electrode assembly accommodated in the exterior body. And this electrochemical element has a resin layer on the inner surface of an exterior body, and is for electrochemical elements formed using the adhesive composition of this invention mentioned above between the resin layer and the electrode assembly. Has an adhesive layer. As described above, the electrochemical device of the present invention has an adhesive layer formed using the adhesive composition disposed between the resin layer on the surface of the exterior body and the electrode assembly. Adhesion with the electrode assembly is good and the electrical characteristics are excellent.
Hereinafter, each component of the electrochemical device will be described.

<Electrode assembly>
The electrode assembly is a structure including a plurality of constituent members such as an electrode and a separator, and may further include a constituent member other than the electrode and the separator (for example, a porous film that reinforces the electrode and the separator) as necessary. Good. The electrode assembly is not particularly limited, and is composed of a laminated body in which electrodes and separators are alternately laminated, or a wound body in which the laminated body is wound.

[electrode]
Although it does not specifically limit as an electrode (For example, the positive electrode in a lithium ion secondary battery, a negative electrode), The electrode by which the electrode compound-material layer was formed on the electrical power collector is mentioned.
Here, the current collector, the components in the electrode mixture layer (for example, the electrode active material and the binder for the electrode mixture layer), and the method for forming the electrode mixture layer on the current collector are known. For example, those described in JP2013-145663A and JP2013-77559A can be used.

[Separator]
The separator is not particularly limited, and for example, those described in JP 2012-204303 A can be used. Among these, the thickness of the separator as a whole can be reduced, thereby increasing the ratio of the electrode active material of the electrochemical element and increasing the capacity per volume. , Polypropylene, polybutene, and polyvinyl chloride) are preferred.

<Exterior body>
Although it does not specifically limit as an exterior body, For example, the exterior body which consists of a film which laminated | stacked the resin layer and metal foil is mentioned. The resin layer may cover the entire inner surface of the exterior body or may cover only a part thereof. Furthermore, the resin layer is preferably a thermoplastic resin layer. This is because if the thermoplastic resin layer is formed on the surface of the exterior body, the adhesive strength between the exterior body and the electrode assembly can be further improved, and the electrical characteristics of the electrochemical element can be further enhanced.
Examples of the thermoplastic resin constituting the thermoplastic resin layer include polypropylene and nylon ethylene-acrylate copolymer. More specifically, for example, biaxially stretched polypropylene called OPP (Oriented Polypropylene), non-axially stretched polypropylene called CPP (Cast Polypropylene), and stretched nylon called ONY (Oriented Nylon). It is done. Moreover, as a metal which comprises metal foil, aluminum is preferable. The thickness of the film constituting the outer package is not particularly limited, but is usually about 50 to 300 μm. Further, the shape of the outer package is appropriately determined according to the shape of the electrochemical element.

<Adhesive layer for electrochemical element>
The electrochemical device of the present invention has a resin layer on the inner surface of the outer package described above, and an adhesive layer formed using the adhesive composition of the present invention between the resin layer and the electrode assembly. . The adhesive layer is made of a dried product of the adhesive composition of the present invention, and is at least one of a carboxylic acid group, a hydroxyl group, an amino group, an epoxy group, an oxazoline group, an isocyanate group, and a sulfonic acid group. Including polymers having one or more functional groups. Furthermore, the adhesive layer preferably further contains an amine compound. In addition, since each component contained in the adhesive layer is contained in the adhesive composition of the present invention, a suitable abundance ratio of these components is determined in the adhesive composition of the present invention. It is the same as the preferred abundance ratio of each component. In addition, when the polymer contained in the adhesive composition has a crosslinkable functional group, the polymer is used during drying of the adhesive composition or during heat treatment that can be optionally performed. Etc. (that is, the adhesive layer may contain a crosslinked polymer). The arrangement mode of the adhesive layer is not particularly limited as long as the electrode assembly can be fixed to the surface of the exterior body, and the entire outer surface of the electrode assembly may be covered or only a part thereof may be covered.

<Electrolyte>
As the electrolytic solution, an organic electrolytic solution in which a supporting electrolyte is dissolved in an organic solvent is usually used.
The supporting electrolyte used in the electrolytic solution, for example in a lithium ion secondary battery or a lithium ion _{_{capacitor, LiPF 6, LiAsF 6, LiBF}} 4, LiSbF 6, LiAlCl 4, LiClO 4, CF 3 SO 3 Li, C 4 F Examples include lithium salts such as ₉ SO ₃ Li, CF ₃ COOLi, (CF ₃ CO) ₂ NLi, (CF ₃ SO ₂ ) ₂ NLi, and (C ₂ F ₅ SO ₂ ) NLi, and are particularly soluble in solvents. From the viewpoint of showing a high degree of dissociation, LiPF ₆ , LiClO ₄ , and CF ₃ SO ₃ Li are preferable.
For example, as an electric double layer capacitor, those described in JP 2010-28007 A can be mentioned, and TEABF ₄ is preferable from the viewpoint of improving low-temperature output characteristics.
In addition, a support electrolyte may be used individually by 1 type, and may be used in combination of 2 or more types.

The organic solvent used for the electrolytic solution is not particularly limited as long as it can dissolve the supporting electrolyte.
For example, in lithium ion secondary batteries and lithium ion capacitors, dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), butylene carbonate (BC), methyl ethyl carbonate (MEC), etc. And the like; esters such as γ-butyrolactone and methyl formate; ethers such as 1,2-dimethoxyethane and tetrahydrofuran; sulfur-containing compounds such as sulfolane and dimethyl sulfoxide; Moreover, you may use the liquid mixture of these solvents. Among these, carbonates are preferable because they have a high dielectric constant and a wide stable potential region.
For example, in the electric double layer capacitor, the above-described carbonates, esters, sulfur-containing compounds, and nitriles such as acetonitrile are preferably used. Moreover, you may use the liquid mixture of these solvents. Among these, acetonitrile is preferable from the viewpoint of improving low-temperature output characteristics.
The concentration of the electrolyte in the electrolytic solution can be adjusted as appropriate. Moreover, you may add a known additive to electrolyte solution.

(Electrochemical element manufacturing method)
The electrochemical device manufacturing method of the present invention includes a coating step of applying any of the above-described adhesive compositions to a resin layer on the surface of the exterior body to obtain a coating film, and drying the coating film. The method includes a drying step of obtaining an electrochemical element adhesive layer, and an adhesive step of bonding the electrode assembly and the outer package through the electrochemical element adhesive layer. If an electrochemical element is manufactured using the adhesive composition of the present invention described above, an electrochemical element having excellent electrical characteristics can be manufactured satisfactorily. In each step described below, as the adhesive composition, the exterior body, the resin layer on the surface of the exterior body, and the electrode assembly, the same ones as already described for the “electrochemical element” can be used.

<Coating process>
In the coating process, the adhesive composition is applied onto the resin layer on the surface of the exterior body. Here, the method for applying the adhesive composition on the resin layer on the surface of the exterior body is not particularly limited. For example, the spray coating method, the doctor blade method, the reverse roll method, the direct roll method, the gravure method, the extrusion method. , Brush coating method, spray coating method, transfer method and the like. Among these, application methods such as a brush coating method, a spray coating method, a transfer method, and a doctor blade method are simple.

Furthermore, the solubility of the resin layer on the surface of the exterior body in the organic solvent is preferably 0.001% or more, more preferably 0.100% or more, and preferably 10.000% or less. More preferably, it is 0.000% or less. If the solubility of the resin layer in the organic solvent is within the above range, the adhesive strength between the outer package and the electrode assembly can be further improved, and the electrical characteristics of the electrochemical device can be further improved. The reason is not clear, but it is assumed that it is as follows. First, the resin layer surface can be roughened by appropriately dissolving the resin layer in the organic solvent. Further, an interaction occurs between the roughened surface and a specific functional group contained in the adhesive composition, and further, when the adhesive composition contains an amine compound, the amine compound. Therefore, it is thought that it leads to improvement of adhesive strength.
In addition, in this specification, "the solubility with respect to the organic solvent of the resin layer of the surface in an exterior body" can be measured by the method as described in an Example.

<Drying process>
In the drying step, the coating film obtained in the coating step is dried to obtain an adhesive layer for electrochemical elements. The drying method is not particularly limited, and a known method can be used, and examples thereof include drying by warm air, hot air, low-humidity air, vacuum drying, and drying by irradiation with infrared rays or electron beams. The drying conditions are not particularly limited, but the drying temperature is preferably 30 to 80 ° C., and the drying time is preferably 30 seconds to 10 minutes.

The thickness of the adhesive layer is preferably 0.01 μm or more, more preferably 0.1 μm or more, further preferably 0.5 μm or more, preferably 20 μm or less, more preferably 10 μm or less, still more preferably 5 μm or less, More preferably, it is 3 μm or less. When the thickness of the adhesive layer is equal to or higher than the lower limit value of the range, the strength of the adhesive layer can be sufficiently secured, and when the thickness is equal to or lower than the upper limit value of the range, the thickness of the electrochemical element is reduced. Can do.

<Adhesion process>
In the bonding step, the electrode assembly and the exterior body are bonded via the bonding layer. More specifically, for example, the electrode assembly can be bonded to the exterior body by enclosing the electrode assembly with the exterior body and pressing the electrode assembly through the exterior body. Here, an expand metal, an overcurrent prevention element such as a fuse or a PTC element, a lead plate, or the like is inserted into the exterior body as necessary to prevent an increase in pressure inside the electrochemical element or overcharge / discharge. Good. The shape of the electrochemical element may be any of a coin shape, a button shape, a sheet shape, a cylindrical shape, a square shape, a flat shape, and the like.

EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. In the following description, “%” and “part” representing amounts are based on mass unless otherwise specified.
In addition, in a polymer produced by copolymerizing a plurality of types of monomers, the proportion of the structural unit formed by polymerizing a certain monomer in the polymer is usually that unless otherwise specified. This coincides with the ratio (preparation ratio) of the certain monomer in the total monomers used for polymerization of the polymer.
In Examples and Comparative Examples, the degree of swelling of the electrolyte of the polymer, the glass transition temperature of the polymer, the surface tension of the adhesive composition for electrochemical elements, the concentration of the amine compound, the adhesiveness of the adhesive layer for electrochemical elements, In addition, the high temperature cycle characteristics and low temperature output characteristics of the electrochemical device were evaluated by the following methods.

<Polymer swelling degree of polymer>
The aqueous dispersion containing the polymer prepared in Examples and Comparative Examples was placed in a petri dish made of polytetrafluoroethylene and dried under conditions of 25 ° C. and 96 hours to obtain a film. Thereafter, it was dried under reduced pressure (200 to 250 mmHg) at 25 ° C. for 10 hours to obtain a film. It cut | judged to 1 cm square and obtained the test piece. The mass W0 of this test piece was measured.
Thereafter, the test piece was immersed in a predetermined electrolytic solution at 60 ° C. for 72 hours. Then, the test piece was taken out from the electrolytic solution, the electrolytic solution on the surface was wiped off, and the mass W1 of the test piece was measured.
From the values of the masses W0 and W1 obtained, the degree of swelling S (times) of the particulate polymer was determined by the formula S = W1 / W0.
As the predetermined electrolytic solution, a nonaqueous electrolytic solution obtained by dissolving a supporting electrolyte at a concentration of 1 mol / L in a predetermined mixed solvent was used. As the predetermined mixed solvent, ethylene carbonate (EC), diethyl carbonate (DEC), and vinylene carbonate (VC) mixed at a volume ratio: EC / DEC / VC = 68.5 / 30 / 1.5 Was used. LiPF ₆ was used as the supporting electrolyte.
<Glass transition temperature of polymer>
In the same manner as when measuring the degree of swelling of the electrolytic solution, a film-like measurement sample containing the polymers prepared in Examples and Comparative Examples was obtained. Then, 10 mg of a measurement sample was weighed into an aluminum pan, and a measurement temperature range of −100 ° C. to 200 ° C. using an empty aluminum pan as a reference with a differential thermal analysis measurement apparatus (“EXSTAR DSC6220” manufactured by SII Nano Technology). The DSC curve was measured at a temperature increase rate of 10 ° C./min at room temperature and normal humidity. During this temperature rising process, the baseline immediately before the endothermic peak of the DSC curve where the differential signal (DDSC) becomes 0.05 mW / min / mg or more and the tangent line of the DSC curve at the first inflection point after the endothermic peak Was determined as the glass transition point (Tg).
<Surface tension of the adhesive composition for electrochemical devices>
The surface tension of the adhesive composition for electrochemical devices prepared in Examples and Comparative Examples was measured using an automatic surface tension meter (“DY-300” manufactured by Kyowa Interface Science Co., Ltd.) at a temperature of 25 ° C. according to the platinum plate method. It was measured.
<Concentration of amine compound>
The concentration of the amine compound in the adhesive composition for electrochemical devices prepared in Examples and Comparative Examples was measured by a gas chromatography method (manufactured by Tosoh Corporation, column “TSK-GEL ODS-100V”, temperature 40 ° C.). did.

<Solubility of resin layer in organic solvent>
The aluminum wrapping material as the exterior material used in the examples and comparative examples was cut into 1 cm square to obtain a total of 5 test pieces. The mass A0 of these five test pieces was measured. Then, the test piece was placed at 72 ° C. at 60 ° C. in 30 g of an organic solvent used in the adhesive composition for electrochemical devices prepared in Examples and Comparative Examples (hereinafter, the mass of the organic solvent is referred to as “Aorg” g). Soaked for hours. Then, the test piece was taken out from the organic solvent, the organic solvent on the surface was wiped off, and the mass A1 of the test piece was measured.
From the obtained values of A0 and A1 and the mass of the organic solvent used for dissolution, the solubility SOL (%) of the resin layer in the organic solvent is measured according to the formula: SOL (%) = (A0−A1) / Aorg × 100. did.

<Adhesive strength of adhesive layer for electrochemical elements>
The adhesive composition for electrochemical devices prepared in Examples and Comparative Examples was applied to the inner surface (side on which the resin layer was formed) of the exterior body using a doctor blade method, and a hot air dryer (90 ° C. , 90 minutes). Then, the negative electrode composite material layer surface of the negative electrode produced in the example and the comparative example is opposed to the inner surface of the exterior body coated with the adhesive composition for electrochemical elements, and the temperature is measured by a flat plate press. The sample for measurement was obtained by pressing for 3 minutes under the conditions of 80 ° C. and a press pressure of 0.75 MPa.
The obtained sample for measurement was subjected to a tensile test using a 180 ° peel tester (tensile speed of 50 mm / min) in an environment of a temperature of 25 ° C. and a humidity of 50%, and the peel strength was measured. Higher peel strength means higher adhesive strength.
A: 0.5 N / mm ≦ P
B: 0.3 N / mm ≦ P <0.5 N / mm
C: 0.1 N / mm ≦ P <0.3 N / mm
D: P <0.1 N / mm

<High temperature cycle characteristics>
After injecting the 1000 mAh laminated lithium ion secondary battery prepared in Examples and Comparative Examples, it was charged at 0.2 C to 3.65 V, left at 60 ° C. for 12 hours, and at 0.2 C to 3.00 V. An aging treatment was performed by discharging. Thereafter, in an environment of 25 ° C., charging and discharging operations were performed by charging at 4.2 V, 0.2 C, and discharging at 3.00 V, 0.2 C, and the initial capacity C0 was measured. Furthermore, charge / discharge was repeated under an environment of 60 ° C., and the capacity C1 after 100 cycles was measured. The high temperature cycle characteristics are evaluated by a capacity retention ratio represented by ΔC = C1 / C0 × 100 (%), and the higher this value, the better the high temperature cycle characteristics.
A: 85% ≦ ΔC
B: 80% ≦ ΔC <85%
C: ΔC <80%
<Low temperature output characteristics>
After injecting the 1000 mAh laminated lithium ion secondary battery in Examples and Comparative Examples, charge it at 0.2 C to 3.65 V, leave it at 60 ° C. for 12 hours, and discharge at 0.2 C to 3.00 V. The aging process was performed. Thereafter, charging was performed at 4.2 V and 0.2 C in an environment of 25 ° C., and the voltage V0 at that time was measured. Thereafter, a discharge operation was performed at a discharge rate of 1 C in an environment of −10 ° C., and the voltage V1 15 seconds after the start of discharge was measured. The low temperature output characteristic is evaluated by a voltage change represented by ΔV = V0−V1, and the smaller this value, the better the low temperature output characteristic.
A: ΔV ≦ 500 (mV)
B: 500 <ΔV (mV) ≦ 700
C: 700 <ΔV (mV)

Example 1
<Preparation of polymer>
A monomer containing 2 parts by mass of methacrylic acid, which is a monomer containing a carboxylic acid group, which is one of the specific functional groups, and an epoxy group, which is one of the specific functional groups, in a 5 MPa pressure vessel with a stirrer 5 parts by mass of allyl glycidyl ether, 78 parts by mass of ethyl acrylate and 15 parts by mass of acrylonitrile as other monomers not containing a specific functional group, 1 part of sodium dodecylbenzenesulfonate as an emulsifier, 150 parts of ion-exchanged water In addition, 0.5 part of potassium persulfate was added as a polymerization initiator, and after sufficiently stirring, the polymerization was started by heating to 60 ° C. When the polymerization conversion rate reached 96%, the reaction was stopped by cooling to produce an aqueous dispersion containing the polymer (solid content concentration 25%). The glass transition temperature of the obtained polymer and the degree of swelling with respect to the electrolytic solution were measured according to the above methods. The results are shown in Table 1.
<Preparation of adhesive composition for electrochemical device>
N-methyl-2-pyrrolidone (surface tension: 34 mN / m) as an organic solvent was added to the solid content of the obtained polymer 10 times, and the mixed solution was depressurized with a vacuum pump while stirring. By removing water at 80 ° C., an adhesive composition for electrochemical elements (solid content concentration 10%) was obtained. Furthermore, the density | concentration of the amine compound in the obtained adhesive composition for electrochemical devices was measured according to the said method. Furthermore, the surface tension of the obtained adhesive composition for electrochemical devices was measured according to the above method. The results are shown in Table 1. Further, the amine compound was confirmed to be methylamine (molecular weight 31) from the retention time of gas chromatography described above.
<Formation of adhesive layer on resin layer on exterior body surface>
The adhesive composition for an electrochemical element obtained according to the above was applied by a doctor blade method onto a polypropylene layer which is a resin layer on the inner surface of an aluminum packaging material (Dai Nippon Printing Co., Ltd.) as an exterior material, and 50 ° C. And dried for 3 minutes to obtain an exterior material having an adhesive layer having a thickness of 1 μm.

<Manufacture of negative electrode>
In a 5 MPa pressure vessel equipped with a stirrer, 33 parts of 1,3-butadiene, 3.5 parts of itaconic acid, 63.5 parts of styrene, 0.4 part of sodium dodecylbenzenesulfonate as an emulsifier, 150 parts of ion-exchanged water and a polymerization initiator After adding 0.5 parts of potassium persulfate as a mixture and sufficiently stirring, the mixture was heated to 50 ° C. to initiate polymerization. When the polymerization conversion rate reached 96%, the reaction was stopped by cooling to obtain a mixture containing a particulate binder (SBR) for the negative electrode mixture layer. A 5% aqueous sodium hydroxide solution was added to the mixture containing the particulate binder and the pH was adjusted to 8, and then the unreacted monomer was removed by heating under reduced pressure. Then, it cooled to 30 degrees C or less, and obtained the water dispersion liquid containing a desired particulate-form binder.
Next, 100 parts of artificial graphite (volume average particle diameter D50: 15.6 μm) as a negative electrode active material and a 2% aqueous solution of carboxymethylcellulose sodium salt (manufactured by Nippon Paper Industries Co., Ltd., “MAC350HC”) as a thickener After substantially adjusting 1 part and ion-exchanged water to adjust the solid content concentration to 68%, the mixture was mixed at 25 ° C. for 60 minutes. Subsequently, it adjusted with ion-exchange water so that solid content concentration might be 62%, and also mixed for 15 minutes at 25 degreeC. Thereafter, 1.5 parts of an aqueous dispersion containing the above-mentioned particulate binder is added to the obtained mixed liquid, and ion-exchanged water corresponding to the solid content, and the final solid content concentration is adjusted to 52%. And mixed for another 10 minutes. This was defoamed under reduced pressure to obtain a negative electrode slurry composition having good fluidity.
Then, the negative electrode slurry composition obtained as described above was applied on a copper foil having a thickness of 20 μm, which is a current collector, with a comma coater so that the film thickness after drying was about 150 μm. , Dried. This drying was performed by conveying the copper foil in an oven at 60 ° C. at a speed of 0.5 m / min for 2 minutes. Thereafter, heat treatment was performed at 120 ° C. for 2 minutes to obtain a single-side negative electrode original fabric. Furthermore, the slurry composition for negative electrodes was apply | coated and dried with respect to the back surface of the obtained negative electrode raw material so that the film thickness after drying might be set to about 150 micrometers. This drying was performed by conveying the copper foil in an oven at 60 ° C. at a speed of 0.5 m / min for 2 minutes. Thereafter, heat treatment was performed at 120 ° C. for 2 minutes to obtain a negative electrode raw material on both sides. The negative electrode raw material on both sides was rolled by a roll press to obtain a negative electrode after pressing with a thickness of the negative electrode mixture layer excluding the current collector of 160 μm (double-sided negative electrode).

<Production of positive electrode>
100 parts of LiCoO ₂ (volume average particle diameter D50: 12 μm) as the positive electrode active material, ₂ parts of acetylene black (“HS-100” manufactured by Denki Kagaku Kogyo Co., Ltd.) as the conductive material, particles for the positive electrode mixture layer Polyvinylidene fluoride (“# 7208”, manufactured by Kureha Co., Ltd.) as a binder was mixed with 2 parts corresponding to the solid content and N-methylpyrrolidone to make the total solid content concentration 70%. These were mixed by a planetary mixer to prepare a positive electrode slurry composition.
The obtained positive electrode slurry composition was applied onto a 20 μm-thick aluminum foil as a current collector by a comma coater so that the film thickness after drying was about 150 μm and dried. This drying was performed by transporting the aluminum foil in an oven at 60 ° C. at a speed of 0.5 m / min for 2 minutes. Thereafter, heat treatment was performed at 120 ° C. for 2 minutes to obtain a single-sided positive electrode raw material. Furthermore, the positive electrode slurry composition was applied to the back surface of the obtained positive electrode original fabric so that the film thickness after drying was about 150 μm and dried. This drying was performed by conveying the copper foil in an oven at 60 ° C. at a speed of 0.5 m / min for 2 minutes. Thereafter, heat treatment was performed at 120 ° C. for 2 minutes to obtain a positive electrode raw material on both sides. The positive electrode fabric on both sides was rolled with a roll press to obtain a pressed positive electrode with a positive electrode mixture layer excluding the current collector having a thickness of 160 μm (double-sided positive electrode).

<Manufacture of electrode assembly and lithium ion secondary battery>
The double-sided positive electrode obtained above is cut out to 5 cm × 15 cm, and a separator (Celgard, “Celguard 2500”) cut into 6 cm × 16 cm is arranged on the upper side (a mixture layer side) so as to face the double-sided positive electrode. did. Furthermore, the double-sided negative electrode cut out to 5.5 cm x 15.5 cm was arrange | positioned at the other side of the separator, and the laminated body A was obtained. On the double-sided negative electrode side of the laminate A, a separator cut into 6 cm × 16 cm was disposed so as to face the double-sided negative electrode. Furthermore, the double-sided positive electrode cut out to 5 cm x 15 cm was piled up on the other side of the separator. Next, a separator cut into 6 cm × 16 cm was further arranged on the double-sided positive electrode so as to face the double-sided positive electrode. Finally, a double-sided negative electrode cut out to 5.5 cm × 5.5 cm was laminated on the separator to obtain a laminate B. The negative electrode located on the outermost side of the laminate B and the outer package of the battery are wrapped with an aluminum packaging material outer layer having an adhesive layer so as to be in contact with the negative electrode, and flat-plate pressed at 0.75 MPa for 3 minutes at 80 ° C. (LiPF ₆ was dissolved as a supporting electrolyte at a concentration of 1 mol / L in a mixed solvent of EC, DEC and VC (EC / DEC / VC (volume ratio at 25 ° C.) = 68.5 / 30 / 1.5). Was injected so that no air remained. Furthermore, heat sealing at 150 ° C. was performed to close the outer packaging of the aluminum packaging material, and a 1000 mAh laminated lithium ion secondary battery was manufactured.
Using the obtained secondary battery, high temperature cycle characteristics and low temperature output characteristics were evaluated. The results are shown in Table 1.

(Examples 2, 6, and 7)
The organic solvent was changed to toluene (Example 2), cyclopentyl methyl ether (Example 6), and isopropyl alcohol (Example 7). Various evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

(Examples 3, 4, 8, 9)
The same procedure as in Example 1 was conducted except that the blending amounts of various monomers blended during the production of the polymer were changed as shown in Table 1. In particular, in Example 9, two parts of 2-acrylamido-2-methylpropanesulfonic acid, which is a monomer containing a sulfonic acid group, were blended in place of allyl glycidyl ether, which is a monomer containing an epoxy group. . Various evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

(Example 5)
N-methyl-2-pyrrolidone used as the organic solvent is purified using an alumina column, and the concentration of the amine compound contained in the adhesive composition for electrochemical devices is as shown in Table 1. The procedure was the same as Example 1 except that the change was made. Various evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
The same procedure as in Example 1 was conducted except that the polymer was prepared by blending as shown in Table 1 and not including a monomer containing a specific functional group when the polymer was prepared. Various evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 2)
The same procedure as in Example 1 was performed except that water was used as a solvent in place of the organic solvent when preparing the adhesive composition for electrochemical devices. Various evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

In Table 1 shown below,
“NMP” refers to N-methyl-2-pyrrolidone;
“MAA” indicates methacrylic acid,
“AGE” refers to allyl glycidyl ether;
“AMPS” refers to 2-acrylamido-2-methylpropanesulfonic acid,
“BA” indicates butyl acrylate,
“EA” indicates ethyl acrylate;
“AN” indicates acrylonitrile,
“ST” indicates styrene,
“CPME” refers to cyclopentyl methyl ether;
“IPA” indicates isopropyl alcohol;
“PP” indicates polypropylene.

From Examples 1 to 9 in Table 1 above, the adhesive layer formed using the adhesive composition for an electrochemical element containing a polymer having a specific functional group and an organic solvent has high adhesive strength. Recognize. In addition, it can be seen that the electrochemical device including the adhesive layer is excellent in high temperature cycle characteristics and low temperature output characteristics.
On the other hand, in Comparative Example 1 in which the polymer does not contain a specific functional group and Comparative Example 2 in which the solvent is water, the adhesion strength of the adhesive layer is insufficient and the electrical performance of the electrochemical element may be inferior. Recognize.

Claims

An adhesive composition for an electrochemical element used for adhesion between an electrode assembly and an exterior body,
Including a polymer and an organic solvent,
The polymer has one or more functional groups of carboxylic acid group, hydroxyl group, amino group, epoxy group, oxazoline group, isocyanate group, and sulfonic acid group,
Adhesive composition for electrochemical devices.
The adhesive composition for electrochemical elements according to claim 1, wherein the surface tension is 10 mN / m or more and 50 mN / m or less.
The electrochemical device according to claim 1 or 2, wherein the outer package has a resin layer on at least an inner surface, and the solubility of the resin layer in the organic solvent is 0.001% or more and 10.000% or less. Adhesive composition.
4. The adhesive composition for electrochemical devices according to claim 1, wherein the polymer has a glass transition temperature of −100 ° C. or higher and 50 ° C. or lower.
The adhesive composition for an electrochemical element according to any one of claims 1 to 4, wherein the degree of swelling of the electrolyte of the polymer is 1 to 10 times.
The adhesive composition for an electrochemical element according to any one of claims 1 to 5, further comprising an amine compound.
An electrochemical element comprising an exterior body and an electrode assembly housed in the exterior body, wherein the exterior body has a resin layer on an inner surface, and the battery assembly is between the resin layer and the electrode assembly. An electrochemical element having an electrochemical element adhesive layer formed using the electrochemical element adhesive composition according to any one of Items 1 to 6.
The electrochemical element according to claim 7, wherein the resin layer of the outer package is a thermoplastic resin layer.
A coating step of applying the adhesive composition for an electrochemical element according to any one of claims 1 to 6 to obtain a coating film on the resin layer of the exterior body;
A drying step of drying the coating film to obtain an adhesive layer for an electrochemical element;
An adhesion step of adhering the electrode assembly and the exterior body through the electrochemical element adhesive layer;
The electrochemical element manufacturing method which manufactures the electrochemical element of Claim 7 or 8 through this.
The method for producing an electrochemical element according to claim 9, wherein the resin layer of the outer package has a solubility in the organic solvent of 0.001% or more and 10.000% or less.