KR20160114044A - Liquid adhesive coating for coating collector - Google Patents

Abstract

An adhesive coating composition for a current collector coat comprising a binder and water, wherein the amount of aggregates generated in the maroon mechanical stability test of the coating solution is less than 0.3 wt.% Based on the solid content, the contact angle with respect to the copper foil is less than 60 , And the measurement result in the roof tack test is 0.5 N / 25 mm or more.

Description

{LIQUID ADHESIVE COATING FOR COATING COLLECTOR}

The present invention relates to an adhesive coating composition for a current collector coat used for producing an electrochemical device.

BACKGROUND ART [0002] Electrochemical devices, such as lithium ion secondary batteries, which are compact, light in weight, have high energy density, and can be repeatedly charged and discharged, are rapidly expanding their demand. BACKGROUND ART [0002] Lithium ion secondary batteries are used in fields such as portable telephones, notebook personal computers, and electric vehicles because of their relatively large energy density.

These electrochemical devices are required to be further improved, such as lowering the resistance, increasing the capacity, and improving the mechanical properties and productivity, in accordance with the expansion and development of applications. In such a situation, a production method with higher productivity is required for the electrochemical device electrode, and various improvements have been made to the electrochemical device electrode material suitable for the production method capable of high-speed molding and the production method.

The electrochemical device electrode is usually formed by laminating an electrode active material layer and an electrode active material layer formed by binding a conductive agent, which is used if necessary, with a binder on a current collector. As a method of forming such an electrode active material layer, Patent Documents 1 and 2 disclose a method of forming an electrode active material layer by spray-drying a slurry containing an electrode active material, rubber particles and a dispersion medium to obtain a particulate electrode material, A method of forming the same is disclosed.

Japanese Patent Publication No. 4219705 Japanese Patent Application Laid-Open No. 2007-18874

In order to improve the adhesion between the electrode active material layer and the current collector, an intermediate layer such as an adhesive layer is formed between the electrode active material layer and the current collector. However, when the electrode active material layer is formed as in the methods disclosed in Patent Documents 1 and 2 in a portion where a coating solution for forming an adhesive layer is not applied, the resistance of the battery is increased and the capacity retention rate is lowered, Performance deteriorates.

In the technique described in Patent Document 1, since the viscosity of the slurry is low because the viscosity adjusting agent is not used when preparing the slurry and the binder is localized on the surface in the particulate electrode material, the obtained particulate electrode material is Liquidity has fallen. Therefore, an electrode having a uniform film thickness can not be produced, resulting in a problem of moldability.

In manufacturing the electrode, for example, a long collector wound in a roll shape is taken out to form an electrode active material layer on the current collector. Therefore, it is required to produce an electrode in which a uniform electrode active material layer is formed on a long current collector. However, in Patent Documents 1 and 2, there is no description on long formability.

An object of the present invention is to provide an adhesive coating solution for a current collector coat capable of producing an electrochemical device electrode having good performance even in long-time molding.

As a result of intensive studies, the inventors of the present invention have found that the above object can be achieved by using an adhesive coating liquid for a current collector having a predetermined physical property value, and have completed the present invention.

That is, according to the present invention,

(1) An adhesive composition for a current collector coat comprising a binder and water, wherein the amount of agglomerates generated in the maroon mechanical stability test of the coating solution is less than 0.3 wt.% With respect to the amount of solids and the contact angle with respect to the copper foil is 60 Deg.], An adhesive coating composition for a current collector having a measurement result of 0.5 N / 25 mm or more in the loop tack test,

(2) an adhesive coating composition for a current collector according to (1), wherein the binder is a particulate binder,

(3) The adhesive composition for a current collector according to (2), wherein the particulate binder has a glass transition temperature of from -40 DEG C to 10 DEG C,

(1) to (3), wherein the concentration of the surfactant is from 0.1 wt.% To less than 3 wt.%, And (4)

(5) The adhesive coating composition for a current collector according to any one of (1) to (4), which contains a tackifier, is provided.

According to the coating solution for an adhesive for a current collector coat according to the present invention, an electrochemical device having good performance can be produced.

Hereinafter, the adhesive coating composition for a current collector of the present invention will be described. The adhesive coating composition for a current collector of the present invention is an adhesive coating composition for a current collector coat containing a binder and water, wherein the amount of aggregate generated in the maroon type mechanical stability test of the coating solution is 0.3 wt% , The contact angle to the copper foil is less than 60 占 and the measurement result in the roof tack test is 0.5 N / 25 mm or more. "Wt.%" Has the same meaning as "wt.%".

(Binder)

The binder used in the present invention is a component for adhering the electrode active materials and the electrode active material with the current collector or other components. Usually, the polymer particles having binding properties are dispersed in water (binder aqueous dispersion) , Or a state of a solution (binder solution) in which a polymer having binding properties is dissolved in water.

Examples of the polymer used for the binder aqueous dispersion include a diene polymer, an acrylic polymer, a fluorine polymer, and a silicone polymer.

Of these, a diene polymer or an acrylic polymer is preferable because the current collector and the electrode active material layer are excellent in adhesion. In addition, the adhesive layer obtained by applying the coating composition for a current collector for a current collector is required to have high redox stability in that it is used for a positive electrode and a negative electrode, and an acrylic polymer is most preferable from the viewpoint of high oxidation stability at the positive electrode.

(Diene polymer)

The diene polymer is a polymer containing a monomer unit obtained by polymerizing a conjugated diene such as butadiene, isoprene and the like. The proportion of the monomer unit obtained by polymerizing the conjugated diene in the diene polymer is usually not less than 40% by weight, preferably not less than 50% by weight, more preferably not less than 60% by weight. Examples of the polymer include homopolymers of conjugated dienes such as polybutadiene and polyisoprene; And copolymers of monomers copolymerizable with conjugated dienes. Examples of the copolymerizable monomer include an?,? - unsaturated nitrile compound such as acrylonitrile and methacrylonitrile; Unsaturated carboxylic acids such as acrylic acid and methacrylic acid; Styrene monomers such as styrene, chlorostyrene, vinyl toluene, t-butyl styrene, vinyl benzoic acid, vinyl vinyl benzoate, vinyl naphthalene, chloromethyl styrene, hydroxymethyl styrene,? -Methyl styrene and divinyl benzene; Olefins such as ethylene and propylene; Halogen-containing monomers such as vinyl chloride and vinylidene chloride; Vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate and vinyl benzoate; Vinyl ethers such as methyl vinyl ether, ethyl vinyl ether and butyl vinyl ether; Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, butyl vinyl ketone, hexyl vinyl ketone, and isopropenyl vinyl ketone; Vinylpyrrolidone, vinylpyridine, vinylimidazole, and other heterocyclic-containing vinyl compounds.

(Acrylic polymer)

The acrylic polymer is a polymer containing a monomer unit obtained by polymerizing an acrylate ester and / or a methacrylate ester. The proportion of the monomer unit obtained by polymerizing the acrylic acid ester and / or the methacrylic acid ester in the acrylic polymer is usually not less than 40% by weight, preferably not less than 50% by weight, more preferably not less than 60% by weight. Examples of the polymer include a homopolymer of an acrylic acid ester and / or a methacrylic acid ester, and a copolymer of the monomer and a copolymerizable monomer. Examples of the copolymerizable monomer include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, and fumaric acid; Carboxylic acid esters having at least two carbon-carbon double bonds such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate and trimethylolpropane triacrylate; Styrene monomers such as styrene, chlorostyrene, vinyl toluene, t-butyl styrene, vinyl benzoic acid, vinyl vinyl benzoate, vinyl naphthalene, chloromethyl styrene, hydroxymethyl styrene,? -Methyl styrene and divinyl benzene; Amide monomers such as acrylamide, N-methylol acrylamide and acrylamide-2-methylpropanesulfonic acid; ?,? - unsaturated nitrile compounds such as acrylonitrile and methacrylonitrile; Olefins such as ethylene and propylene; Diene-based monomers such as butadiene and isoprene; Halogen-containing monomers such as vinyl chloride and vinylidene chloride; Vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate and vinyl benzoate; Vinyl ethers such as methyl vinyl ether, ethyl vinyl ether and butyl vinyl ether; Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, butyl vinyl ketone, hexyl vinyl ketone, and isopropenyl vinyl ketone; Vinylpyrrolidone, vinylpyridine, vinylimidazole, and other heterocyclic-containing vinyl compounds.

Examples of the polymer used in the binder solution include polymers such as hydroxyethyl cellulose (HEC), polyethylene glycol (PEG), polyethylene oxide (PEO), polyvinyl alcohol (PVA), polyvinylpyrrolidone (PPA), polyacrylamide (PMMA), polyvinylformamide (PNVF), polyacrylic acid (PAA), sodium polyacrylate (PAA-Na), ammonium polyacrylate (PAA- NH4), sodium polystyrene sulfonate (PSS-Na), carboxymethylcellulose sodium (CMC-Na), polyethyleneimine (PEI) and the like.

The binder used in the present invention is preferably obtained through a particulate metal removal step for removing particulate metal contained in the binder aqueous dispersion or binder solution in the production process. When the content of the particulate metal component contained in the binder is 10 ppm or less, there is less risk of an internal short circuit of the battery or an increase in self-discharge due to dissolution and precipitation at the time of charging, and the cycle characteristics and safety of the battery are improved.

The method for removing the particulate metal component from the binder aqueous dispersion or the binder solution in the particulate metal removal step is not particularly limited and includes, for example, a method of removing by filtration using a filtration filter, A method of removing by centrifugation, a method of removing by magnetic force, and the like. Among them, a method of removing by a magnetic force is preferable because the object to be removed is a metal component. The method of removing by the magnetic force is not particularly limited as long as it is a method capable of removing the metal component. However, considering productivity and removal efficiency, preferably, the magnetic filter is disposed in the production line of the binder.

It is preferable that the binder has a cationic group or an anionic group.

A group cationic group refers to a substituent having the chemistry of the functional cationic, substituents, formula _{R 1 R 2 R 3 R 4} N + (A -) have the formula,, R ₁ is as follows.

R ₁ is a group represented by the formula -CH ₂ -CHOH-CH ₂ -, or -CH ₂ -CH ₂ -, and R ₂ , R ₃ , and R ₄ are each independently an alkyl having 1 to 20 carbon atoms or An arylalkyl group, and A ^- is a halide ion, a sulfate ion, a phosphate ion, or a tetrafluoroborate ion.

When the binder is produced, the cationic group-containing ethylenically unsaturated monomer may be copolymerized, and then, if necessary, subjected to a neutralization treatment or quaternarization treatment to incorporate a cationic group in the binder. Examples of the cationically unsaturated ethylenically unsaturated monomer include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dipropylaminoethyl (meth) acrylate, diisopropylaminoethyl (meth) (Meth) acrylate, dibutylaminoethyl (meth) acrylate, diisobutylaminoethyl (meth) acrylate, ditbutylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, diethylaminopropyl (Meth) acrylamide, diisopropylaminopropyl (meth) acrylamide, diisopropylaminopropyl (meth) acrylamide, dibutylaminopropyl (meth) acrylamide, diisobutylaminopropyl (Meth) acrylate or (meth) acrylamide having a dialkylamino group such as propyl (meth) acrylamide; Styrenes having dialkylamino groups such as dimethylaminostyrene and dimethylaminomethylstyrene; Vinylpyridines such as 4-vinylpyridine and 2-vinylpyridine; N-vinyl heterocyclic compounds such as N-vinylimidazole; Aminoethyl vinyl ether, and dimethylaminoethyl vinyl ether; an acid neutralized product or a quaternary ammonium salt of a monomer having an amino group; And diallyl type quaternary ammonium salts such as dimethyldiallylammonium chloride and diethyldiallylammonium chloride.

The anionic group is a group having a substituent and an anionic chemical functional group. Examples of the anionic chemical functional group include a carboxylate, a sulfate, a sulfonate, a phosphate, a phosphonate, or a mixture thereof. have.

When an anionic group-containing ethylenically unsaturated monomer is copolymerized in the production of a binder, an anionic group may be contained in the binder. The anionic group-containing ethylenically unsaturated monomer is not particularly limited and includes, for example, ethylenically unsaturated monocarboxylic acid monomers such as acrylic acid and methacrylic acid; Ethylenically unsaturated polycarboxylic acid monomers such as itaconic acid, maleic acid, fumaric acid, and buttentricarboxylic acid; Partial ester monomers of ethylenically unsaturated polycarboxylic acids such as monobutyl fumarate, monobutyl maleate, and 2-hydroxypropyl maleate; Polycarboxylic acid anhydrides such as maleic anhydride and citraconic anhydride; Ethylenically unsaturated carboxylic acid monomers such as ethylenically unsaturated carboxylic acid monomers; Monomers having sulfonic acid groups such as styrenesulfonic acid, allyloxybenzenesulfonic acid, methallyloxybenzenesulfonic acid, vinylsulfonic acid, allylsulfonic acid, methallylsulfonic acid, and 4-sulfonic acid butyl methacrylate; . These monomers may be used singly or in combination of two or more.

In the binder used in the present invention, the content of the monomer unit used for containing the anionic group or the cationic group is preferably 0.5 to 5 wt.%, More preferably 1 to 4 wt.%. If the content of the monomer unit is excessively high, the resistance of the obtained electrochemical device electrode becomes high. When the content of the monomer unit is too small, the amount of aggregate in the resulting coating solution for an adhesive for a current collector increases.

The shape of the binder used in the present invention is not particularly limited, but it is preferably in a particulate form. The particles are stable, the binding property is good, and the deterioration due to repetition of charging and discharging can be suppressed in the capacity of the produced electrode. Examples of the particulate binder include those in which particles of a binder such as latex are dispersed in water, and those obtained in the form of a powder obtained by drying such a dispersion.

The average particle diameter of the binder in the binder aqueous dispersion is preferably 50 to 500 nm, more preferably 70 to 400 nm.

The glass transition temperature (Tg) of the binder is appropriately selected depending on the purpose of use, and is preferably -40 ° C to 10 ° C, more preferably -35 ° C to 10 ° C, and more preferably -30 ° C or more 0 deg. C or lower. If the Tg of the binder is too high, the tackiness of the obtained adhesive agent coating solution for a current collector coat is lost. If the Tg of the binder is too low, the strength of the obtained electrochemical device electrode is lowered.

The solid content concentration of the binder water dispersion is preferably 15 to 70 wt.%, More preferably 20 to 65 wt.%, Further preferably 20 to 65 wt.%, From the viewpoint of good workability in production of the adhesive coating composition for a current collector. Preferably 30 to 60 wt.%.

(Surfactants)

The adhesive coating composition for a current collector of the present invention may contain a surfactant. The surfactant is not particularly limited as long as it imparts wettability to the current collector of the coating composition for a current collector, but it is preferable to use a nonionic surfactant from the viewpoint of less adverse effect on the resulting electrochemical device . Examples of the nonionic surfactant include polyoxyalkylene alkylaryl ether surfactants, polyoxyalkylene alkyl ether surfactants, polyoxyalkylene fatty acid ester surfactants, sorbitan fatty acid ester surfactants, silicone surfactants, acetylenic alcohol surfactants Surfactants, fluorinated surfactants, and the like.

Examples of the polyoxyalkylene alkyl aryl ether surfactant include polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether and polyoxyethylene dodecylphenyl ether.

Examples of the polyoxyalkylene alkyl ether surfactant include polyoxyethylene oleyl ether and polyoxyethylene lauryl ether.

Examples of the polyoxyalkylene fatty acid ester surfactant include polyoxyethylene oleic acid ester, polyoxyethylene lauric acid ester, and polyoxyethylene distearic acid ester.

Examples of the sorbitan fatty acid ester surfactant include sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, polyoxyethylene stearate, and the like .

Examples of silicone surfactants include dimethylpolysiloxane and the like.

Examples of acetylene alcohol surfactants include 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5- -1-hexyne-3-ol and the like.

Examples of fluorinated surfactants include fluoroalkyl esters and the like.

The content of the surfactant in the coating solution for the current collector for a current collector of the present invention is 0.1 wt.% Or more and less than 3 wt.%, Preferably 0.1 wt.% Or more and less than 1 wt.%, More preferably 0.2 wt To less than 0.8 wt.%. If the content of the surfactant is excessively high, the resistance of the resulting lithium ion secondary battery increases. If the content of the surfactant is too small, the coating solution for an adhesive for a current collector can not be applied on the current collector.

(Tackifier)

The adhesive coating composition for a current collector of the present invention may contain a tackifier. As the tackifier, polyhydric alcohols are preferably used. Specific examples thereof include ethylene glycol, glycerin, propylene glycol, diethylene glycol, diglycerin, triethylene glycol, tetraethylene glycol, trimethylolpropane and the like . These polyhydric alcohols may be used alone or in combination of two or more. Of these, glycerin or propylene glycol is particularly preferably used from the viewpoints of volatility and plasticity.

The content of the tackifier in the coating composition for an electric current collector coat of the present invention is preferably 0.5 to 10 wt.%, More preferably 1 to 5 wt.%. If the content of the tackifier is too large, the performance of the obtained lithium ion secondary battery deteriorates. If the content of the tackifier is too small, desired tackiness can not be imparted.

(Adhesive Coating Solution for Collector Coating)

The method for producing the coating solution for an adhesive for a current collector of the present invention is not particularly limited, and any means may be used as long as it can disperse the respective solid components in the dispersion medium. For example, a binder aqueous dispersion containing a binder, a surfactant and / or a tackifier, if necessary, are mixed at one time, and then a dispersion medium is added if necessary, and water is added to the solid content The concentration may be adjusted. In addition, at least one of the surfactant and the tackifier may be added to the binder aqueous dispersion containing the binder in a state of being dissolved or dispersed in water.

The viscosity of the collector coating agent for coat coat may vary depending on the coating method, but is preferably 10 to 10,000 mPa · s, more preferably 20 to 20,000 mPa · s, from the viewpoint of forming a uniform adhesive layer on the current collector To 5,000 mPa s, more preferably from 50 to 2,000 mPa s.

The amount of agglomerates generated in the maroon type mechanical stability test of the coating agent for a collector coat is less than 0.3 wt.%, Preferably less than 0.2 wt.%, More preferably less than 0.1 wt.% Based on the solid content. Here, the amount of agglomerates generated in the Maron type mechanical stability test is the ratio (wt.%) Of agglomerate amount (residue) to the amount of solid content in the sample, , And drying it. If the amount of agglomerates generated in the Maron type mechanical stability test is excessively large, agglomerates are generated during coating of the coating solution for an adhesive for a current collector.

Further, the contact angle of the adhesive composition for a current collector with respect to the copper foil is less than 60 deg., Preferably less than 50 deg., More preferably less than 45 deg. If the contact angle is too large, the coating solution for the current collector coat for the current collector coat is repelled at the time of coating.

The measurement result of the loop coat test of the adhesive coating liquid for a collector coat can be measured by a loop test conducted in a state in which an adhesive coating liquid for a current collector coating is applied to a current collector, Mm or more, preferably 1.0 N / 25 mm or more, and more preferably 2.0 N / 25 mm or more. Here, the measurement result of the loop tack test was obtained by measuring the loop tack under an atmosphere of 25 캜 according to FINAT-1991 FTM-9 (Quick-stick tack measurement). A polyethylene terephthalate film coated with a coating solution for an electric current collector coat of the present invention having a thickness of 2 mu m was used for the test panel in the loop tack test.

If the result of the loop tack test is too small, the adhesive force of the adhesive layer formed by the adhesive coating composition for a current collector coat is lowered.

(A collector on which an adhesive layer is formed)

By applying the coating solution for an electric current collector for a current collector of the present invention on a current collector, it is possible to obtain a current collector in which an adhesive layer having an adhesive layer formed on the current collector is formed.

The material of the current collector is, for example, metal, carbon, conductive polymer or the like, preferably a metal. As the metal for the current collector, aluminum, platinum, nickel, tantalum, titanium, stainless steel, copper, and other alloys are usually used. Of these, copper, aluminum or an aluminum alloy is preferably used in terms of conductivity and withstand voltage.

The thickness of the current collector is preferably 5 to 100 占 퐉, more preferably 8 to 70 占 퐉, and still more preferably 10 to 50 占 퐉.

The coating method of the adhesive layer is not particularly limited. For example, an adhesive layer is formed on the current collector by a doctor blade method, a dipping method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, a die coating method, brush application or the like. Alternatively, after the adhesive layer is formed on the release paper, it may be transferred to the current collector.

The applied adhesive layer may be dried. Examples of the drying method include drying by hot air, hot air, low-humidity air, vacuum drying, and irradiation with (circle) infrared rays or electron beams. Among them, a hot air drying method and a far infrared ray drying method are preferable. The drying temperature and the drying time are preferably a temperature and a time at which the solvent in the coating composition for an electric current collector coat applied on the current collector can be completely removed and the drying temperature is usually 50 to 300 ° C, To 250 ° C. The drying time is usually 2 hours or less, preferably 5 seconds to 30 minutes. Further, it is preferable that the adhesive layer formed by the coating composition for an electric current collector for a current collector of the present invention has a tack without heating after coating the current collector.

The thickness of the adhesive layer is preferably from 0.5 to 5 占 퐉, more preferably from 0.5 to 4 占 퐉, particularly preferably from 0.5 to 3 占 퐉, from the viewpoint of obtaining good adhesion to the electrode active material layer to be.

The adhesive layer has a composition according to the solid content of the coating composition for an electric current collector for a current collector, and contains a binder, a surfactant to be used if necessary, and a tackifier.

(Electrochemical device electrode)

The electrode active material layer is formed on the current collector on which the adhesive layer is formed, whereby an electrochemical device electrode can be obtained. The method of forming the electrode active material layer is not particularly limited, but it is preferable to use the composite particles containing the electrode active material to laminate the electrode active material layer on the current collector on which the adhesive layer is formed.

When the electrode active material layer is laminated on the current collector on which the adhesive layer is formed, the composite particles may be formed into a sheet and then laminated on the current collector on which the adhesive layer is formed. A molding method is preferable. As a method of press molding, for example, a roll-type press-forming apparatus provided with a pair of rolls is used, while a current collector having an adhesive layer formed thereon is transferred to a roll, while the composite particles are roll-pressed by a feeding device such as a screw feeder A roll press forming method in which an electrode active material layer is formed on a current collector on which an adhesive layer is formed or a method in which composite particles are dispersed on a collector on which an adhesive layer is formed and the thickness of the composite particles is adjusted by a blade or the like , Followed by molding with a pressurizing device, a method of filling the composite particles into a mold, and molding the mold by pressurization. Of these, a roll pressing method is preferred. Particularly, since the composite particles of the present invention have a high fluidity, the fluidity of the composite particles enables molding by roll pressing, thereby improving the productivity.

The roll temperature at the time of performing the roll pressing is preferably 25 to 200 DEG C, more preferably 50 to 150 DEG C, from the viewpoint of enabling sufficient adhesion between the electrode active material layer and the current collector on which the adhesive layer is formed , More preferably 80 to 120 ° C. The press line pressure between the rolls during roll press forming is preferably 10 to 1000 kN / m, more preferably 200 to 900 kN / m, more preferably 200 to 900 kN / m, from the viewpoint of improving the uniformity of the thickness of the electrode active material layer. More preferably 300 to 600 kN / m. The molding speed in roll pressing is preferably 0.1 to 20 m / min, more preferably 4 to 10 m / min.

In order to eliminate variations in the thickness of the formed electrochemical device electrode and to increase the density of the electrode active material layer to increase the capacity, further post-pressurization may be performed as necessary. As a post-pressurizing method, a press process by a roll is preferable. In the roll pressing step, two circumferential rolls are vertically arranged in parallel at a narrow interval, and the rolls are rotated in opposite directions to press the electrodes by engaging them. At this time, the temperature of the roll may be adjusted by heating or cooling, if necessary.

(Composite particle)

The composite particles are obtained by granulating using an electrode active material, a binder, and other components such as a water-soluble polymer and a conductive agent added as needed. The method for producing the composite particles is not particularly limited, but may be carried out by using a slurry for composite particles containing an electrode active material, a binder and other components such as a conductive agent to be added, if necessary, by spray drying and granulation, For example, an agitation type granulation method, an extrusion granulation method, a crushing granulation method, a fluidized bed granulation method, a fluidized bed multifunctional granulation method, and a melt granulation method. Of these, the spray-drying granulation method is preferable from the viewpoint that the composite particles can be relatively easily produced.

(Slurry for composite particles)

The slurry for composite particles used in the production of the composite particles is formed by dispersing or dissolving the electrode active material, the conductive agent, the binder, and other components added as needed in the dispersion medium.

(Electrode active material)

Examples of the electrode active material (positive electrode active material) for a positive electrode of a lithium ion secondary battery in the case where the electrochemical device is a lithium ion secondary battery include metal oxides capable of reversibly doping and dedoping lithium ions. Examples of such metal oxides include lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium iron phosphate and the like. In addition, the positive electrode active materials exemplified above may be suitably used singly or in a mixture of plural kinds thereof.

Examples of the active material (negative electrode active material) of the negative electrode as the counter electrode of the positive electrode of the lithium ion secondary battery include low crystalline carbon (amorphous carbon) such as graphitizable easy carbon, hard graphitizable carbon, Graphite (natural graphite, artificial graphite), alloy materials such as tin and silicon, oxides such as silicon oxide, tin oxide and lithium titanate. The negative electrode active materials exemplified above may be suitably used singly or as a mixture of plural kinds thereof.

It is preferable that the shape of the electrode active material for a lithium ion secondary battery electrode is set in a granular form. If the shape of the particles is granular, a higher density electrode can be formed at the time of electrode formation.

The volume average particle diameter of the electrode active material for the lithium ion secondary battery electrode is usually 0.1 to 100 占 퐉, preferably 0.5 to 50 占 퐉, more preferably 0.8 to 30 占 퐉 in both the positive electrode and the negative electrode.

(Conductive agent)

Specific examples of the conductive agent used in the present invention include conductive carbon blacks such as permes black, acetylene black, and Ketjenblack (registered trademark of Akzo Nobel Chemicals Co., Ltd.). Of these, acetylene black and furnace black are more preferable.

These conductive agents may be used alone or in combination of two or more.

(Binder)

As the binder to be used in the production of the composite particles, the same binder as the binder used for the coating solution for an adhesive for a current collector can be used.

(Other components)

The slurry for composite particles may contain other components such as a dispersant, if necessary. Specific examples of the dispersing agent include cellulosic polymers such as carboxymethylcellulose and methylcellulose, and ammonium or alkali metal salts thereof. These dispersants may be used alone or in combination of two or more.

(Production of composite particles)

The composite particles are obtained by, for example, spray drying the slurry containing the electrode active material, the conductive agent, the binder and other components to be added as required. Here, the composite particles contain at least an electrode active material, a conductive agent, and a binder. However, the composite particles are not present as individual particles independently of each other, but may be two or more components containing an electrode active material and a binder To form one particle. Specifically, a plurality of individual particles of two or more components are combined to form secondary particles, and a plurality (preferably several to several tens) of electrode active materials are bound by a binder to form particles .

The average particle diameter of the composite particles is preferably 0.1 to 200 占 퐉, more preferably 1 to 150 占 퐉, and still more preferably 10 to 80 占 퐉 in view of easily obtaining an electrode active material layer having a desired thickness. In the present invention, the average particle diameter is the volume average particle diameter measured by a laser diffraction particle size distribution analyzer (for example, SALD-3100; manufactured by Shimadzu Corporation).

(Electrochemical device)

Examples of the usage of the electrochemical device electrode include a lithium ion secondary battery and a lithium ion capacitor using such an electrode, and a lithium ion secondary battery is preferable. For example, a lithium ion secondary battery uses an electrochemical device electrode obtained as described above in at least one of a positive electrode and a negative electrode, and further includes a separator and an electrolytic solution.

(Separator)

As the separator, for example, a porous film or nonwoven fabric containing a polyolefin resin such as polyethylene or polypropylene, or an aromatic polyamide resin; A porous resin coat containing an inorganic ceramic powder; Etc. may be used.

The thickness of the separator is preferably 0.5 to 40 占 퐉, more preferably 1 占 퐉 to 40 占 퐉, from the viewpoint of reducing the resistance of the separator in the lithium ion secondary battery and improving the workability in the production of the lithium ion secondary battery. To 30 m, and more preferably from 1 to 25 m.

(Electrolytic solution)

The electrolytic solution is not particularly limited, and for example, a solution obtained by dissolving a lithium salt as a supporting electrolyte in a nonaqueous solvent can be used. Lithium salts include, for _{example, LiPF 6, LiAsF 6, LiBF} 4, LiSbF 6, LiAlCl 4, LiClO 4, CF 3 SO 3 Li, C 4 F 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. LiPF ₆ , LiClO ₄ , and CF ₃ SO ₃ Li, which are particularly soluble in solvents and exhibit high dissociation, are preferably used. These may be used alone or in combination of two or more. The amount of the supporting electrolyte is usually 1 wt.% Or more, preferably 5 wt.% Or more, and usually 30 wt.% Or less, preferably 20 wt.% Or less, based on the electrolytic solution. If the amount of the supporting electrolyte is excessively small or excessively large, the ionic conductivity decreases and the charging and discharging characteristics of the battery deteriorate.

The solvent used for the electrolytic solution is not particularly limited as long as it dissolves the supporting electrolyte. Usually, the solvent used in the electrolytic solution is dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC) (BC), and methyl ethyl carbonate (MEC); ethers such as tetrahydrofuran and 1,2-dimethoxyethane; Sulfolane, and dimethyl sulfoxide; Is used. Particularly, dimethyl carbonate, ethylene carbonate, propylene carbonate, diethyl carbonate and methyl ethyl carbonate are preferable because they are easy to obtain high ionic conductivity and have a wide temperature range for use. These may be used alone or in combination of two or more. It is also possible to add an additive to the electrolytic solution. As the additive, a carbonate-based compound such as vinylene carbonate (VC) is preferable.

Examples of the electrolytic solution other than the above include gelated polymer electrolytes in which a polymer electrolyte such as polyethylene oxide or polyacrylonitrile is impregnated with an electrolytic solution, inorganic solid electrolytes such as lithium sulfide, LiI, Li ₃ N, Li ₂ SP ₂ S ₅ glass ceramics, .

The lithium ion secondary battery is obtained by superposing the negative electrode and the positive electrode via a separator and winding or bending the negative electrode and the positive electrode in accordance with the shape of the battery, placing the electrode in the battery container, and injecting and sealing the electrolyte solution into the battery container. If necessary, an over-current preventing element such as expanded metal, a fuse, or a PTC element, or a lead plate may be inserted to prevent an increase in pressure inside the battery and overcharge discharge. The shape of the battery may be a laminate cell type, a coin type, a button type, a sheet type, a cylindrical type, a square type, or a flat type.

According to the coating solution for an adhesive for a current collector of the present invention, it is possible to produce an electrochemical device electrode having excellent performance even in long-time molding.

Example

EXAMPLES The present invention will be described in more detail with reference to the following examples, but it should be understood that the present invention is not limited to the following examples, but may be carried out without departing from the scope and spirit of the invention . In the following description, "% " and " part " representing amounts are based on weight unless otherwise specified.

In the Examples and Comparative Examples, the evaluation of the peel strength and the capacity retention rate was carried out as follows.

<Peel Strength>

A lithium ion secondary battery electrode (negative electrode in Example 7, other examples and comparative example) manufactured by using 50 m of final (terminal end, hereinafter the same) out of current collectors formed with the adhesive layers obtained in Examples and Comparative Examples and In the comparative example, the positive electrode) was cut into a rectangular shape having a length of 100 mm and a width of 10 mm to obtain a test piece. The test piece was attached to a cellophane tape fixed to a test stand. At the time of sticking, the surface of the electrode active material layer side was brought into contact with the adhesive surface of the cellophane tape with the surface of the electrode active material layer facing downward. As the cellophane tape, those specified in JIS Z 1522 were used.

Thereafter, one end of the current collector was vertically upwardly pulled at a tensile speed of 50 mm / min and the stress at the time of peeling was measured. This measurement was carried out three times, and the average value was obtained, and the average value was determined as the peak intensity. The larger the fill strength, the larger the binding force of the electrode active material layer to the current collector, i.e., the larger the adhesion strength.

A: 3.0 N / m or more

B: 2.0 N / m or more and less than 3.0 N / m

C: not less than 1.0 N / m and not more than 2.0 N / m

D: Less than 1.0 N / m

<Capacity retention rate (final 50 m and initial 50 m)>

Of the current collectors formed with the adhesive layers obtained in the examples and the comparative examples, the lithium ion secondary batteries produced using the final 50 m and the first 50 m were subjected to a constant current constant voltage charging method at 60 DEG C and 0.5 C, And then charged to a constant voltage. Thereafter, a charge-discharge cycle test was conducted in which the battery was discharged to 3.0 V at a constant current of 0.5 C. The charge-discharge cycle test was carried out up to 100 cycles. The ratio of the discharge capacity at the 100th cycle to the initial discharge capacity was determined as the capacity retention rate. Ten samples were produced in each of the examples and the comparative examples, and the samples with the smallest capacity retention rate among the ten samples were judged according to the following criteria. The larger this value is, the smaller the capacity decrease due to repetitive charging and discharging is.

A: Capacity retention rate is 90% or more

B: Capacity retention rate is 80% or more and less than 90%

C: Capacity retention ratio is 70% or more and less than 80%

D: Capacity retention rate is 60% or more and less than 70%

E: Capacity retention rate less than 60%

The maroon type mechanical stability test, roof tack test, and contact angle measurement were carried out on the coating solution for an electric current collector for a current collector obtained in Examples and Comparative Examples as follows.

<Marron type machine stability test>

The pH of the coating solution for an adhesive for a current collector obtained in Examples and Comparative Examples was adjusted to 8 ± 0.1, and the resultant was filtered through a 100 mesh wire net, and then the solid content concentration was adjusted to 30%. This was filtered through a 100-mesh wire mesh and then submitted to a Maron-type mechanical stability test. Conditions were set at 1000 rpm and weighted 15 kg for 10 minutes. After the maroon type mechanical stability test, the adhesive for the current collecting coat was filtered with a wire mesh of 100 mesh, and the coagulated matter collected by filtration on the wire net was dried and weighed to determine the amount of coagulated matter. The ratio (%) of the coating solution to the solid content weight was determined.

<Loop tack test>

The loop tack of the current collector coated with the coating solution for a current collector for a current collector obtained in Examples and Comparative Examples under an atmosphere of 25 캜 was measured in accordance with FINAT-1991 FTM-9 (Quick-stick tack measurement) Respectively. The larger the value, the better the tack.

&Lt; Contact angle measurement &

The contact angle of the coating solution for an adhesive for a current collector obtained in Examples and Comparative Examples was observed using &quot; DMs-400 &quot; manufactured by Kyowa Interface Science Co., Specifically, 2 占 퐇 of the adhesive agent coating solution for a current collector coat was dripped onto the electrolytic surface of an electrolytic copper foil (product name "NC-WS", thickness 20 占 퐉, manufactured by Furukawa Electric Co., Ltd.). The droplet 1 minute after dropping was observed from the horizontal direction using a measuring apparatus. From the observed images, the contact angle of the electrodeposited copper foil and the collector coating solution for the current collector was calculated by the? / 2 method.

The positive electrode active material for a current collector of Examples and Comparative Examples, a lithium ion secondary battery positive electrode, a lithium ion secondary battery negative electrode, and a lithium ion secondary battery were produced as follows.

(Example 1)

(Production of binder)

300 parts of ion-exchanged water, 93.8 parts of n-butyl acrylate, 2 parts of acrylonitrile, 1.0 part of allyl glycine ether, 2.0 parts of itaconic acid, 1.2 parts of N-methylol acrylamide and 10 parts of t -Dodecylmercaptan (0.05 part) and potassium persulfate (0.3 part) as a polymerization initiator were placed, and the mixture was sufficiently stirred and heated to 70 DEG C to polymerize to obtain a particulate binder containing an acrylic polymer having a solid content concentration of 40% Lt; / RTI &gt; binder) was obtained. The polymerization conversion rate determined from the solid content concentration was approximately 99%. The obtained particulate binder had a Tg of -20 占 폚.

(Production of adhesive coating composition for current collector)

(Hereinafter referred to as &quot; PG &quot;) as a tackifier, 0.5 wt.% Of a nonionic surfactant, Distanol TOC (manufactured by Nichiyu Co., Ltd.) as a surfactant, , A binder, a surfactant, a tackifier, and water were mixed so as to have a content of 1 wt.% In the binder resin. The amount of agglomerates generated in the maroon type mechanical stability test of the obtained coating solution for a current collector for a current collector was 0.05 wt.%, And the contact angle to the copper foil was 30 °.

(Production of composite particles)

(Referred to as LiCoO _2, referred to as "LCO"), lithium cobalt oxide as a positive electrode active material (particle diameter: 6 ㎛) 92 parts of acetylene black (Denki Chemical Co., the binder as 2.0 parts, the conductive agent in terms of solid mass quantity production Denka 5.0 parts of a 1.5% aqueous solution of carboxymethyl cellulose (DN-800H: manufactured by Daicel Chemical Industries, Ltd.) as a dispersing agent was mixed in an amount of 1.0 part in terms of solid content, Exchanged water was added so as to have a solid content concentration of 40% and mixed and dispersed to obtain a slurry for positive electrode composite particles. The slurry for composite particles for positive electrode was dried at a rotation speed of 25,000 rpm, a hot air temperature of 150 占 폚, and a temperature of 150 占 폚 using a spray dryer (manufactured by Okawara Chemical Industry Co., Ltd.) Spray drying and granulation were carried out at a temperature of 90 캜 to obtain composite particles. The average particle diameter of the composite particles was 50 탆.

(Formation of adhesive layer)

An aluminum current collector having a thickness of 10 占 퐉 was coated with an adhesive coating composition for current collector coat at a molding speed of 20 m / min by a gravure coating method at a current density of 1000 m and dried at 120 占 폚 for 2 minutes, Thereby obtaining a current collector having an adhesive layer formed with an adhesive layer having a thickness of 1.2 mu m. The loop tack of the adhesive layer in the current collector in which the obtained adhesive layer was formed was 6 N / 25 mm.

(Preparation of Positive Electrode of Lithium Ion Secondary Battery)

The current collector having the adhesive layer formed thereon was transported at a speed of 2 m / min, and the positive electrode active material layer was formed on a roll (roll temperature 100 ° C, press line pressure 4 kN / cm) of a roll press machine And formed into a sheet on a collector on which an adhesive layer was formed to obtain a lithium ion secondary battery positive electrode having a thickness of 60 占 퐉.

(Production of negative electrode slurry and lithium ion secondary battery negative electrode)

96 parts of artificial graphite (average particle diameter: 24.5 占 퐉, graphite interlayer distance (plane spacing of (002) plane by the X-ray diffraction method: 0.354 nm: 0.354 nm), and styrene-butadiene copolymer latex BM- ) As a dispersant, 1.0 part of a 1.5% aqueous solution of carboxymethylcellulose (DN-800H, manufactured by Daicel Chemical Industries, Ltd.) in terms of solid content as a dispersant, and further adding ion-exchanged water to a solid content concentration of 50% , And mixed and dispersed to obtain a negative electrode slurry. The negative electrode slurry was applied to a copper foil having a thickness of 18 占 퐉 and dried at 120 占 폚 for 30 minutes, followed by roll pressing to obtain a negative electrode having a thickness of 50 占 퐉.

(Preparation of separator)

A single-layered polypropylene separator (width 65 mm, length 500 mm, thickness 25 占 퐉, manufactured by the dry method, porosity of 55%) was cut out in a square of 5 占 5 cm2.

(Production of lithium ion secondary battery)

An aluminum-coated sheath was prepared as an exterior of the battery. The positive electrode of the lithium ion secondary battery obtained above was cut out into a square of 4 x 4 cm 2, and the surface of the current collector side was disposed so as to be in contact with the aluminum-covered sheath. On the surface of the positive electrode active material layer of the positive electrode of the lithium ion secondary battery, a square separator obtained as described above was disposed. Further, the lithium ion secondary battery negative electrode obtained above was cut into a square of 4.2 x 4.2 cm &lt; 2 &gt;, and the negative electrode active material layer surface was disposed on the separator so as to face the separator. Further, a 1.0 M LiPF ₆ solution containing 2.0% of vinylene carbonate was charged. The solvent of the LiPF ₆ solution is a mixed solvent of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (EC / EMC = 3/7 (volume ratio)). Further, in order to seal the openings of the aluminum foil, heat sealing was carried out at 150 DEG C to remove the aluminum sheath to produce a laminate type lithium ion secondary battery (laminate type cell).

(Example 2)

A binder was produced in the same manner as in Example 1, except that the amount of itaconic acid used was one part in the production of the binder. The Tg of the particulate binder obtained in Example 2 was -20 占 폚. A positive electrode active material for a current collector coating, a positive electrode for a lithium ion secondary battery, a negative electrode for a lithium ion secondary battery, and a lithium ion secondary battery were produced in the same manner as in Example 1 except that this binder was used.

The amount of agglomerates produced in the maroon type mechanical stability test of the coating solution for a current collector for a current collector obtained in Example 2 was 0.1 wt.%, The contact angle with respect to the copper foil was 30 °, and the loop tack was 5 N / 25 mm.

(Example 3)

In the same manner as in Example 1 except that a binder, a surfactant, a tackifier and water were mixed so that the concentration of diphenol TOC as a surfactant was 0.1 wt.% In the production of an adhesive coating composition for a current collector, Production of an adhesive coating solution for a current collector, production of a lithium ion secondary battery positive electrode, a lithium ion secondary battery negative electrode and a lithium ion secondary battery were carried out.

The amount of agglomerates generated in the maroon mechanical stability test of the coating solution for a current collector for a current collector obtained in Example 3 was 0.05 wt.%, The contact angle to the copper foil was 50 占 and the loop tack was 5 N / 25 mm.

(Example 4)

A binder was produced in the same manner as in Example 1 except that a particulate binder having a Tg of 0 캜 was obtained in the production of the binder. The binder was used to prepare an adhesive coating composition for a current collector, a positive electrode for a lithium ion secondary battery, a negative electrode for a lithium ion secondary battery, and a lithium ion secondary battery in the same manner as in Example 1.

The amount of agglomerates generated in the maroon type mechanical stability test of the coating solution for a current collector for a current collector obtained in Example 4 was 0.05 wt.%, The contact angle to the copper foil was 30 °, and the loop tack was 1 N / 25 mm.

(Example 5)

In producing the coating composition for a current collector for a coat, a binder, a surfactant, and a tackifier were added so that the concentration of diphenol TOC as a surfactant was 0.2 wt.% And the concentration of propylene glycol as a tackifier was 2 wt. A positive electrode for a lithium ion secondary battery, a negative electrode for a lithium ion secondary battery, and a lithium ion secondary battery were produced in the same manner as in Example 4, except that a mixture of ash and water was mixed.

The amount of agglomerates generated in the maroon type mechanical stability test of the coating solution for a current collector for a current collector obtained in Example 5 was 0.05 wt.%, The contact angle to the copper foil was 30 °, and the loop tack was 6 N / 25 mm.

(Example 6)

In the preparation of the coating solution for a collector for a current collector, glycerin was used as a tackifier, and the concentration of diaspartol TOC as a surfactant was 0.8 wt.%, And the concentration of glycerin as a tackifier was 1 wt.%. A positive electrode active material for a positive electrode active material, a negative electrode active material, a binder, a surfactant, a tackifier, and water in the same manner as in Example 1, Respectively.

The amount of agglomerates generated in the maroon type mechanical stability test of the coating solution for a current collector for a current collector obtained in Example 6 was 0.05 wt.%, The contact angle to the copper foil was 30 °, and the loop tack was 5 N / 25 mm.

(Example 7)

(Production of adhesive coating composition for current collector)

(BM-400B) (hereinafter sometimes referred to as &quot; SBR binder &quot;) was used in place of the binder in the production of an adhesive coating composition for a current collector, A binder, a surfactant, a tackifier, and water were mixed so that the distanol TOC as an activator and the tackifier glycol as a tackifier were 1 wt.% And 0.8 wt.%, Respectively, to obtain an adhesive coating composition for a current collector.

The amount of agglomerates generated in the maroon type mechanical stability test of the coating solution for a current collector for a current collector obtained in Example 7 was 0.05 wt.%, The contact angle to the copper foil was 30 °, and the loop tack was 8 N / 25 mm.

(Production of composite particles)

92 parts of artificial graphite (average particle diameter: 24.5 占 퐉, graphite interlayer distance (plane spacing of (002) plane by X-ray diffraction method: 0.354 nm) of negative electrode active material, 92 parts of styrene-butadiene copolymer latex BM- (DN-800H, manufactured by Daicel Chemical Industries, Ltd.) as a dispersant in an amount of 1.0 part by weight in terms of solid content, and further adding ion-exchanged water to a solid content concentration of 40 The slurry for composite particles for negative electrode was prepared by using an atomizer (diameter: 65 mm) of a rotary disc type using a spray drier (manufactured by Okawa Chemical Industries, Ltd.), and mixing and dispersing the mixture to obtain a slurry for negative electrode composite particles. , Spray-drying and granulation were carried out at a revolution of 25,000 rpm, a hot air temperature of 150 ° C and a temperature of the particle recovery outlet of 90 ° C to obtain composite particles. The average volume particle The diameter was 50 탆.

(Production of a positive electrode slurry and a positive electrode of a lithium ion secondary battery)

(PVDF; "KF-1100" manufactured by Kureha Chemical Industries, Ltd.) as a positive electrode binder was added to 92 parts of LiCoO ₂ as a positive electrode active material (hereinafter abbreviated as "LCO" , 6 parts of acetylene black ("HS-100" manufactured by Denki Kagaku Kogyo) and 20 parts of N-methylpyrrolidone were added and mixed with a planetary mixer to obtain a positive electrode slurry. This positive electrode slurry was applied to an aluminum foil having a thickness of 18 占 퐉, dried at 120 占 폚 for 30 minutes, and then rolled to obtain a lithium ion secondary battery positive electrode having a thickness of 60 占 퐉.

(Production of lithium ion secondary battery)

A separator similar to that of Example 1 was prepared and the lithium ion secondary battery positive electrode and the positive electrode of the lithium ion secondary battery obtained in Example 7 were used to fabricate a laminate type lithium ion secondary battery ).

(Example 8)

In the same manner as in Example 1 except that polyethylene oxide was used instead of the binder as the binder in the production of the collector coating solution for a current collector for a current collector coating, a binder, a surfactant, The preparation of a coating agent for an entire coat, a positive electrode of a lithium ion secondary battery, a negative electrode of a lithium ion secondary battery, and a lithium ion secondary battery.

The amount of agglomerates produced in the maroon type mechanical stability test of the coating solution for an electric current collector for a current collector obtained in Example 8 was 0 wt.%, The contact angle to the copper foil was 35 °, and the loop tack was 2 N / 25 mm.

(Comparative Example 1)

A binder was produced in the same manner as in Example 1 except that itaconic acid was not used in the production of the binder. The Tg of the particulate binder obtained in Comparative Example 1 was -20 占 폚. The binder was used to produce an adhesive coating solution for a current collector coat without using a tackifier in the production of a coating solution for an adhesive for current collecting coats. A lithium ion secondary battery positive electrode, a lithium ion secondary battery negative electrode and a lithium ion secondary battery were produced in the same manner as in Example 1 except that the adhesive coating composition for a current collector for use in Comparative Example 1 was used.

In addition, the amount of agglomerates generated in the maroon type mechanical stability test of the coating solution for a current collector for a current collector obtained in Comparative Example 1 was 0.5 wt.%, The contact angle to the copper foil was 30 °, and the loop tack was 4 N / 25 mm.

(Comparative Example 2)

Production of an adhesive coating composition for a current collecting coat, preparation of a coating solution for a current collector, coating of a lithium ion &lt; RTI ID = 0.0 &gt; A secondary battery positive electrode, a lithium ion secondary battery negative electrode, and a lithium ion secondary battery.

The amount of agglomerates produced in the maroon type mechanical stability test of the coating solution for a current collector for a current collector obtained in Comparative Example 2 was 0.1 wt.%, The contact angle to the copper foil was 60 °, and the loop tack was 4 N / 25 mm.

(Comparative Example 3)

A binder was produced in the same manner as in Example 1 except that a particulate binder having a Tg of 10 DEG C was obtained in the production of the binder. Using this binder, a binder, a surfactant, a tackifier and water were mixed so as to have 0.05 wt.% Of diphenol TOC as a surfactant and 1 wt.% Of propylene glycol as a tackifier. An entire coating adhesive coating solution was prepared. A positive electrode of a lithium ion secondary battery, a negative electrode of a lithium ion secondary battery, and a lithium ion secondary battery were produced in the same manner as in Example 1 except that the current collector coating solution for a current collector was used.

The amount of agglomerates generated in the maroon mechanical stability test of the coating solution for a current collector for a current collector obtained in Comparative Example 3 was 0.1 wt.%, The contact angle to the copper foil was 80 占 and the loop tack was 0.1 N / 25 mm.

As shown in Table 1, an adhesive coating liquid for a current collector coat containing a binder and water was prepared in the same manner as in Example 1 except that the amount of aggregates generated in the maroon type mechanical stability test of the coating liquid was less than 0.3 wt% The peel strength of the electrode for a lithium ion secondary battery using the adhesive coating solution for a current collector having a contact angle of less than 60 DEG and a measurement result of a loop tack test of 0.5 N / 25 mm or more was satisfactory, The capacity retention rate of the lithium ion secondary battery including the lithium ion secondary battery electrode using the liquid was good both in the initial 50 m and the final 50 m.

Claims (5)

An adhesive coating composition for a current collector coat containing a binder and water,
The amount of agglomerates generated in the maroon mechanical stability test of the coating liquid was less than 0.3 wt.% With respect to the solid content,
The contact angle to the copper foil is less than 60 DEG,
An adhesive coating composition for a current collector having a measurement result of 0.5 N / 25 mm or more in a loop tack test. The method according to claim 1,
Wherein the binder is a particulate binder. 3. The method of claim 2,
Wherein the particulate binder has a glass transition temperature of from -40 占 폚 to 10 占 폚. 4. The method according to any one of claims 1 to 3,
Wherein the concentration of the surfactant is less than 0.1 wt.% And less than 3 wt.%. 5. The method according to any one of claims 1 to 4,
An adhesive coating composition for a current collector coat containing a tackifier.