JP2017069006A - Binder composition for battery electrode and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a binder composition for a battery electrode with low internal resistance, which is excellent in coating properties of a slurry positive electrode material composition in forming a positive electrode, which is high in binding properties, which causes no oxidation degradation under a positive electrode environment, and which provides an aqueous binder with less environmental load.SOLUTION: A binder composition for a battery electrode contains: a polymer containing (A) a (meth)acrylic monomer and (B) a constituent unit derived from a multifunctional (meth)acrylate monomer; and a nonion-based surfactant and an anion-based surfactant, as (C) an emulsifier.SELECTED DRAWING: None

Description

  The present invention relates to a binder composition for battery electrodes used for battery electrodes. In this specification, the battery includes an electrochemical capacitor and is a primary battery or a secondary battery. Specific examples of the battery are a lithium ion secondary battery and a nickel metal hydride secondary battery.

It is known to use a binder in the battery electrode. A typical example of a battery having an electrode using a binder is a lithium ion secondary battery.
Lithium ion secondary batteries have high energy density and high voltage, and are therefore used in electronic devices such as mobile phones, notebook computers, and camcorders. Recently, due to heightened awareness of environmental protection and the development of related laws, applications as in-vehicle applications such as electric vehicles and hybrid electric vehicles and storage batteries for household power storage are also progressing.

  A lithium ion secondary battery is generally composed of a negative electrode, a positive electrode, a separator, an electrolytic solution, and a current collector. Regarding the electrode, the negative electrode is coated on a current collector typified by copper foil with a negative electrode active material such as graphite or hard carbon capable of inserting and removing lithium ions, a conductive additive, a binder, and a solvent. Obtained by drying. Currently, styrene-butadiene rubber (hereinafter abbreviated as “SBR”) dispersed in water is generally used as a binder.

  On the other hand, the positive electrode is made by mixing a layered positive electrode active material such as lithium cobaltate or spinel type lithium manganate with a conductive auxiliary such as carbon black, a binder such as polyvinylidene fluoride or polytetrafluoroethylene, and the like. The coating liquid dispersed in such a polar solvent is manufactured by applying and drying on a current collector foil represented by an aluminum foil in the same manner as the negative electrode.

  The binder of these lithium ion batteries needs to increase the addition amount of the binder in order to ensure the binding force, and the performance degradation due to this is mentioned as a problem. Further, N-methylpyrrolidone is used as a slurry solvent, and an aqueous binder is desired from the viewpoint of recovery, cost, toxicity and environmental load. However, when an aqueous SBR binder is used, there is a problem that it is oxidized and deteriorated in a positive electrode environment. Therefore, the binder of the positive electrode still uses polyvinylidene fluoride or polytetrafluoroethylene using N-methylpyrrolidone as a dispersion solvent as a binder, and binds the current collector to the active material or between the active materials. There is an urgent need to develop a binder suitable for the production of an electrode for a secondary battery, which is superior in water quality, has a low environmental impact, and has high oxidation resistance.

  Recently, in order to solve the above problems, Patent Documents 1 and 2 propose a binder made of an acrylic emulsion as an aqueous binder component. However, when these binders are used for the positive electrode, there is a problem that the interfacial resistance between the electrode and the current collector and the internal resistance of the battery become high, and there is a concern that the battery characteristics deteriorate.

JP 2014-116265 A JP 2006-260782 A

  The present invention has been made in view of the above circumstances, and is a battery-based binder composition for battery electrodes that has a high binding property and does not cause oxidative deterioration in a positive electrode environment and has a low environmental load and a low internal resistance. The purpose is to provide.

As a result of repeated studies to achieve the above object, the present inventors have found that the above problems can be solved by using a specific binder composition for battery electrodes, and have completed the present invention. That is, the present invention relates to the following.
Item 1.
(A) a polymer containing a structural unit derived from a (meth) acrylic monomer and (B) a structural unit derived from a polyfunctional (meth) acrylate monomer; and (C) a nonionic surfactant as an emulsifier; A binder composition comprising an anionic surfactant.
Item 2.
Item (1) wherein (A) (meth) acrylic monomer is (A-1) a (meth) acrylate monomer having a hydroxyl group, (A-2) (meth) acrylate monomer, and (A-3) (meth) acrylic acid monomer. The binder composition described.
Item 3.
(A-1) The binder composition according to Item 2, wherein the (meth) acrylic monomer having a hydroxyl group is an alkylene glycol mono (meth) acrylate monomer having a molecular weight of 100 to 1,000.
Item 4.
(B) The binder composition according to any one of Items 1 to 3, wherein the polyfunctional (meth) acrylate monomer is a 2 to 5 functional (meth) acrylate.
Item 5.
The anionic surfactant is an anionic surfactant selected from sulfate ester type, carboxylic acid type, sulfonic acid type, and phosphate ester type, and the nonionic surfactant is a polyoxyalkylene type nonionic surfactant. Item 5. The binder composition according to any one of Items 1 to 4.
Item 6.
Item 6. The binder composition according to any one of Items 1 to 5, wherein the content of the anionic surfactant and the nonionic surfactant is from 0.01 to 10% by weight based on the amount of monomers charged.
Item 7.
Item 7. The binder composition according to any one of Items 1 to 6, wherein the ratio of the content of the anionic surfactant and the nonionic surfactant is 1:10 to 10: 1.
Item 8.
Production of a binder composition obtained by polymerizing (A) (meth) acrylic monomer and (B) polyfunctional (meth) acrylate monomer in water using a nonionic surfactant and an anionic surfactant. Method.
Item 9.
A battery electrode comprising at least the binder composition according to any one of Items 1 to 7, an active material, and a conductive additive.
Item 10.
A battery obtained by using the electrode according to Item 9.

The binder composition for battery electrodes containing the nonionic surfactant and the anionic surfactant of the present invention provides an electrode having excellent flexibility.
The binder composition for battery electrodes containing the nonionic surfactant and the anionic surfactant of the present invention is suppressed from being dissolved in the electrolytic solution, and is not substantially dissolved in the electrolytic solution. This insolubility is considered to be due to a highly crosslinked structure by using a structural unit derived from a polyfunctional (meth) acrylate monomer as a crosslinking agent component.
If a surfactant is contained in the binder composition, it is considered that the coating properties are deteriorated due to remarkable thickening of the battery electrode slurry, and the battery oxidation / reduction reaction is adversely affected to deteriorate the battery characteristics. However, the binder composition for battery electrodes containing the nonionic surfactant and the anionic surfactant of the present invention can suppress remarkable thickening of the slurry for battery electrodes, so that the coating property is improved. As a result of good dispersibility of the slurry, it is possible to provide a battery, particularly a secondary battery, which has low internal resistance of the electrode, suppresses deterioration of battery characteristics, has high capacity, has a long battery life, and excellent charge / discharge characteristics. Can do.
The secondary battery of the present invention can be used at a high voltage and has excellent heat resistance.
Since the binder composition for battery electrodes is aqueous (medium is water), it has a low environmental load and does not require an organic solvent recovery device.

The binder composition for battery electrodes of the present invention comprises (A) a structural unit derived from a (meth) acrylate monomer,
(B) a structural unit derived from a polyfunctional (meth) acrylate monomer,
A polymer comprising
(C) A binder composition for battery electrodes, comprising a nonionic surfactant and an anionic surfactant as an emulsifier.

  (A) (Meth) acrylic monomers include (A-1) (meth) acrylate monomers having a hydroxyl group, (A-2) (meth) acrylate monomers, and (A-3) (meth) acrylic acid monomers. Each of these can be used alone or in combination of two or more.

  (A-1) The (meth) acrylate monomer having a hydroxyl group is preferably an alkylene glycol mono (meth) acrylate having a molecular weight of 100 to 1,000. Specific examples include diethylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, tetraethylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, dipropylene glycol mono (meth) acrylate, and tripropylene glycol. Examples thereof include mono (meth) acrylate, tetrapropylene glycol mono (meth) acrylate, and polypropylene glycol mono (meth) acrylate. These can be used alone or in combination of two or more. Among these, tetraethylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, tetrapropylene glycol mono (meth) acrylate, and polypropylene glycol mono (meth) acrylate are preferable.

  Specific examples of (A-2) (meth) acrylate monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, and (meth) acrylic acid n. -Butyl, isobutyl (meth) acrylate, n-amyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and (meth) acrylic acid Examples include (meth) acrylic acid alkyl esters such as lauryl. Preferred are methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and isopropyl (meth) acrylate. These (meth) acrylic acid ester monomers can be used alone or in combination of two or more.

  (A-3) Specific examples of the (meth) acrylic acid monomer include methacrylic acid and acrylic acid, which can be used alone or in combination of two or more. Two combinations of methacrylic acid and acrylic acid may be used in a weight ratio of 1:99 to 99: 1, for example 5:95 to 95: 5, in particular 20:80 to 80:20.

  (B) The polyfunctional (meth) acrylate monomer serves as a crosslinking agent. (B) As a polyfunctional (meth) acrylate monomer, bifunctional-pentafunctional (meth) acrylate is mentioned. A bifunctional to pentafunctional cross-linking agent is excellent in dispersion by emulsion polymerization and has excellent physical properties (flexibility and binding properties) as a binder. (B) The polyfunctional (meth) acrylate monomer is preferably a trifunctional or tetrafunctional (meth) acrylate.

  Specific examples of the bifunctional (meth) acrylate include triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetrapropylene glycol di Examples thereof include (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, dioxane glycol di (meth) acrylate, and bis (meth) acryloyloxyethyl phosphate.

  Specific examples of trifunctional (meth) acrylates include trimethylolpropane tri (meth) acrylate, trimethylolpropane EO-added tri (meth) acrylate, trimethylolpropane PO-added tri (meth) acrylate, and pentaerythritol tri (meth) acrylate. 2,2,2-tris (meth) acryloyloxymethylethyl succinic acid, ethoxylated isocyanuric acid tri (meth) acrylate, ε-caprolactone modified tris- (2- (meth) acryloxyethyl) isocyanurate, glycerin EO Addition tri (meth) acrylate, glycerin PO addition tri (meth) acrylate, tris (meth) acryloyloxyethyl phosphate, and the like can be mentioned. Among these, trimethylolpropane tri (meth) acrylate, trimethylolpropane EO-added tri (meth) acrylate, and pentaerythritol tri (meth) acrylate are preferable.

  Specific examples of the tetrafunctional (meth) acrylate include ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, and pentaerythritol EO-added tetra (meth) acrylate.

  Specific examples of the pentafunctional (meth) acrylate include dipentaerythritol penta (meth) acrylate.

  A polyfunctional (meth) acrylate may be 1 type or can use 2 or more types together.

  The quantity of the structural unit of polyfunctional (meth) acrylate is 0.5-70 weight part with respect to 100 weight part of structural unit of (A) (meth) acryl monomer, for example, 1-60 weight part, Especially 2-50. It may be part by weight.

  The polymer of the present invention is a polymer containing (A) a structural unit derived from a (meth) acrylic monomer, (B) a structural unit derived from a polyfunctional (meth) acrylate monomer, and (A) The (meth) acrylic monomer includes (A-1) a structural unit derived from a (meth) acrylate monomer having a hydroxyl group, (A-2) a structural unit derived from a (meth) acrylate monomer, (A-3) ) It may have a structural unit derived from a (meth) acrylic acid monomer.

  In the polymer, (A-1) a structural unit derived from a monomer having a hydroxyl group, (A-2) a structural unit derived from a (meth) acrylate monomer, and (A-3) derived from a (meth) acrylic acid monomer. The ratio of the structural units derived from the (B) polyfunctional (meth) acrylate monomer is (A-1) 1-99.9% by weight, (A-2) 80-0% by weight and ( A-3) 15 to 0 wt%, (B) 20 to 0.1 wt%, preferably (A-1) 5 to 90 wt%, (A-2) 75 to 5 wt% and (A- 3) 13 to 0 wt%, (B) 18 to 1 wt%.

  Other monomers include fumaric acid, maleic acid, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, crotonnitrile, α-ethylacrylonitrile, α-cyanoacrylate, vinylidene cyanide Fumaronitrile or the like can be used.

  As a method for obtaining the polymer of the present invention, there can be used a general emulsion polymerization method, a soap-free emulsion polymerization method, a seed polymerization method, a method in which a monomer or the like is swollen in seed particles and then polymerized. Specifically, a composition containing a monomer, an emulsifier, a polymerization initiator, water, and a dispersant, a chain transfer agent, a pH adjuster, etc. at room temperature in an airtight container equipped with a stirrer and a heating device is an inert gas. Monomers and the like are emulsified in water by stirring in an atmosphere. As a method of emulsification, a method using stirring, shearing, ultrasonic waves, or the like can be applied, and a stirring blade, a homogenizer, or the like can be used. Next, by starting the polymerization by raising the temperature while stirring, a spherical polymer latex in which the polymer is dispersed in water can be obtained. The monomer addition method at the time of polymerization may be monomer dropping, pre-emulsion dropping, or the like in addition to batch preparation, and two or more of these methods may be used in combination.

  The particle structure of the polymer in the binder of the present invention is not particularly limited. For example, a latex of a polymer containing composite polymer particles having a core-shell structure produced by seed polymerization can be used. As the seed polymerization method, for example, a method described in “Dispersion / Emulsification System Chemistry” (Publisher: Engineering Books Co., Ltd.) can be used. Specifically, this is a method in which a monomer, a polymerization initiator, and an emulsifier are added to a system in which seed particles produced by the above method are dispersed to grow core particles, and the above method may be repeated one or more times.

  You may employ | adopt the particle | grains using the polymer of this invention, or a well-known polymer for seed polymerization. Examples of the known polymer include polyethylene, polypropylene, polyvinyl alcohol, polystyrene, poly (meth) acrylate, and polyether, but are not limited, and other known polymers can be used. Further, one kind of homopolymer or two or more kinds of copolymers or blends may be used.

  Examples of the particle shape of the polymer in the binder of the present invention include a plate shape, a hollow structure, a composite structure, a localized structure, a daruma-shaped structure, an octopus-like structure, a raspberry-like structure, etc. Particles having two or more types of structures and compositions can be used without departing from the scope.

  The particle diameter of the polymer in the binder composition for battery electrodes of the present invention can be measured by a dynamic light scattering method, a transmission electron microscope method, an optical microscope method, or the like. The average particle diameter calculated from the scattering intensity obtained using the dynamic light scattering method is 0.001 μm to 1 mm, preferably 0.001 μm to 0.500 mm. Specific examples of the measuring device include Spectris Zetasizer Nano.

  As the emulsifier of the present invention, a nonionic surfactant and an anionic surfactant are used. Nonionic surfactants include, for example, polyoxyethylene alkyl ether, polyoxyethylene alcohol ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene polycyclic phenyl ether, polyoxyalkylene alkyl ether, polyoxyethylene units and polyoxypropylene Examples include polyoxyalkylene types such as polyalkylene glycol having a unit, sorbitan fatty acid ester, polyoxyethylene fatty acid ester and polyoxyethylene sorbitan fatty acid ester, and reactive nonionic surfactants include Latemul PD-420, 430, 450 (manufactured by Kao Corporation), Adekaria soap ER (manufactured by Adeka company), Aqualon RN (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Antox LMA (manufactured by Nippon Emulsifier Co., Ltd.), Antox MH (manufactured by Nippon Emulsifier Co., Ltd.), and the like.

Examples of the anionic surfactant include a sulfate ester type, a carboxylic acid type, a sulfonic acid type, and a phosphate ester type surfactant. A sulfate ester type, a sulfonic acid type, and a phosphate ester type are preferable, The sulfuric ester type is particularly preferred.
The sulfuric acid ester type includes alkyl sulfuric acid such as lauryl sulfuric acid and dodecyl sulfuric acid, polyoxyethylene alkyl ether sulfuric acid such as polyoxyethylene dodecyl ether sulfuric acid, polyoxyethylene isodecyl ether sulfuric acid, polyoxyethylene tridecyl ether sulfuric acid, and polyoxyalkylene. Examples include alkali metal salts such as alkenyl ether sulfuric acid, sodium salts and potassium salts thereof, ammonium salts such as ammonium salts, triethanolamine salts, and aminomethylpropanol salts, and sodium salts, ammonium salts, and triethanolamine salts. Is preferred. Specific examples of sulfate-type reactive anionic surfactants include Latemul PD-104, 105 (manufactured by Kao Corporation), Adekaria Soap SR (manufactured by Adeka Corporation), Aqualon HS (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Aqualon KH (Daiichi Kogyo Seiyaku Co., Ltd.) is mentioned. Preferably, sodium lauryl sulfate, ammonium dodecyl sulfate, triethanolamine dodecyl sulfate, latemul PD-104 and the like can be mentioned.
Examples of the carboxylic acid type include polyoxyethylene lauryl ether acetate, lauryl sulfosuccinate, polyoxyethylene sulfosuccinate lauryl salt, polyoxyethylene alkylsulfosuccinate, higher fatty acid salt, naphthenate, etc., and sodium Preferred are alkali metal salts such as salts and potassium salts, and amine salts such as ammonium salts, triethanolamine salts, and aminomethylpropanol salts, and particularly preferred are sodium salts, ammonium salts, and triethanolamine salts. Specific examples include Neo Haitenol ECL-30S, ECL-45 (Daiichi Kogyo Seiyaku), Neo Haitenol LS (Daiichi Kogyo Seiyaku), Neo Haitenol L-30S (Daiichi Kogyo Seiyaku), Neo Hightenol S-70 (Daiichi Kogyo Seiyaku Co., Ltd.), Calisetken HY (Daiichi Kogyo Seiyaku Co., Ltd.) and the like can be mentioned.
As the sulfonic acid type, di-2-ethylhexylsulfosuccinic acid, 2-ethylhexyldiphenyl ether disulfonic acid, dodecylsulfonic acid, dodecanesulfonic acid, n-hexylbenzenesulfonic acid, octadecanesulfonic acid, tetrapropylenebenzenesulfonic acid, linear or Branched dodecylbenzenesulfonic acid, polynaphthylmethanesulfonic acid, ligninsulfonic acid, N-methyl-N-acyl tauric acid, styrenesulfonic acid, polystyrenesulfone, alkali metal salts such as sodium salt and potassium salt, ammonium salt Amine salts such as triethanolamine salt and aminomethylpropanol salt are preferable, and sodium salt, ammonium salt and triethanolamine salt are preferable. Specific examples include Neogen S-20F, SC-F (Daiichi Kogyo Seiyaku), SAS-12F (Daiichi Kogyo Seiyaku), Neogen AO-90 (Daiichi Kogyo Seiyaku), Neogen PSA-C (No. Ichi Kogyo Seiyaku), Neocor SW, SW-C, P, YSK (Daiichi Kogyo Seiyaku), Monogen Y-100, Y-500T (Daiichi Kogyo Seiyaku) and the like.
The phosphoric acid ester types include polyoxyethylene tridecyl ether phosphate, polyoxyethylene styrenated phenyl ether phosphate, polyoxyalkylene decyl ether phosphate, polyoxyethylene lauryl ether phosphate, polyoxyethylene alkyl Examples include ether phosphates, alkyl phosphates, alkali metal salts such as sodium salts and potassium salts thereof, and amine salts such as ammonium salts, triethanolamine salts, and aminomethylpropanol salts. Specific examples include Prisurf A212C, A215C (Daiichi Kogyo Seiyaku), Prisurf AL, AL12-H (Daiichi Kogyo Seiyaku), Prisurf A208F, A208N (Daiichi Kogyo Seiyaku) Prisurf M208F (No. 1) Ichi Kogyo Seiyaku Co., Ltd.), Prisurf A208B, A210B, A219B (Daiichi Kogyo Seiyaku), Prisurf DB-01 (Daiichi Kogyo Seiyaku), Prisurf A210D (Daiichi Kogyo Seiyaku), Prisurf DBS, DOM (Daiichi Kogyo Seiyaku Co., Ltd.).

These nonionic surfactants and anionic surfactants are used as a mixture. One type or two or more types of surfactants may be used. By using a nonionic surfactant and an anionic surfactant in combination, the dispersibility of the active material and conductive auxiliary of the battery electrode slurry formulated with a small addition amount is improved, and the thickening of the slurry is prevented. The coating property at the time of electrode formation becomes good. Further, as a synergistic effect, the internal resistance of the battery is lowered, the deterioration of the battery characteristics is suppressed, the battery life is long, and the charge / discharge characteristics are improved. This is because the lipophilic effect of the nonionic surfactant and the repulsive effect of the charge of the anionic surfactant are well contributing to the dispersion of the binder and the conductive auxiliary agent, and the dispersibility is improved. It is thought that the packing of the positive electrode active material and the conductive additive after drying is improved, and the conductive path is increased.

  The reactivity of the reactive surfactant means that it contains a reactive double bond and undergoes a polymerization reaction with the monomer during polymerization. That is, the reactive surfactant acts as an emulsifier for the monomer during the polymerization for producing the polymer, and is in a state of being covalently incorporated into a part of the polymer after the polymerization. Therefore, the emulsion polymerization and the dispersion of the produced polymer are good, and the physical properties (flexibility, binding property) as a binder are excellent. Further, since the reactive surfactant becomes a part of the polymer, the reactive surfactant is not liberated, so that it is considered that the dissolution of the surfactant in the electrolytic solution is suppressed, and the battery performance is improved.

  The amount of the constituent unit of the emulsifier may be an amount generally used in the emulsion polymerization method. Specifically, it is in the range of 0.01 to 25% by weight, preferably 0.05 to 20% by weight, and more preferably 0.1 to 20% by weight with respect to the charged monomer amount.

  The mixing ratio of the nonionic surfactant and the anionic surfactant is specifically 1:10 to 10: 1, preferably 1: 5 to 5: 1, more preferably 4: 1 to 1: 4. is there. This is because if the amount of the nonionic surfactant is too large, the internal resistance increases, whereas if it is too small, a sufficient synergistic effect cannot be exhibited.

As the polymerization initiator, a polymerization initiator generally used in an emulsion polymerization method or a suspension polymerization method can be used. The emulsion polymerization method is preferred. In the emulsion polymerization method, a water-soluble polymerization initiator is used, and in the suspension polymerization method, an oil-soluble polymerization initiator is used.
Specific examples of the water-soluble polymerization initiator include water-soluble polymerization initiators represented by persulfates such as ammonium persulfate, 2-2′-azobis [2- (2-imidazolin-2-yl) propane. Or its hydrochloride or sulfate, 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], 2,2'-azobis (2-methylpropaneamidine), or its hydrochloride Or sulfate, 3,3 ′-[azobis [(2,2-dimethyl-1-iminoethane-2,1-diyl) imino]] bis (propanoic acid), 2,2 ′-[azobis (dimethylmethylene)] A polymerization initiator of a water-soluble azo compound such as bis (2-imidazoline) is preferred.
Examples of oil-soluble polymerization initiators include organic peroxides such as cumene hydroperoxide, benzoyl peroxide, acetyl peroxide, and t-butyl hydroperoxide, azobisisobutyronitrile, 1,1'-azobis (cyclohexane A polymerization initiator of an oil-soluble azo compound such as (carbonitrile) is preferable. These polymerization initiators may be used alone or in combination of two or more.

  The amount of the polymerization initiator used may be an amount generally used in the emulsion polymerization method or suspension polymerization method. Specifically, it is in the range of 0.01 to 5% by weight, preferably 0.01 to 3% by weight, and more preferably 0.02 to 1% by weight, with respect to the monomer amount charged.

  A chain transfer agent can be used as needed. Specific examples of the chain transfer agent include n-hexyl mercaptan, n-octyl mercaptan, t-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-stearyl mercaptan and other alkyl mercaptans, 2,4-diphenyl-4 -Xanthogen compounds such as methyl-1-pentene, 2,4-diphenyl-4-methyl-2-pentene, dimethylxanthogen disulfide, diisopropylxanthogen disulfide, terpinolene, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetramethylthiuram mono Thiuram compounds such as sulfide, phenol compounds such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol, allyl compounds such as allyl alcohol, di Halogenated hydrocarbon compounds such as lormethane, dibromomethane, carbon tetrabromide, vinyl ethers such as α-benzyloxystyrene, α-benzyloxyacrylonitrile, α-benzyloxyacrylamide, triphenylethane, pentaphenylethane, acrolein, methacrolein , Thioglycolic acid, thiomalic acid, 2-ethylhexyl thioglycolate, and the like, and these may be used alone or in combination. The amount of these chain transfer agents is not particularly limited, but is usually 0 to 5 parts by weight with respect to 100 parts by weight of the charged monomer.

  The polymerization time and polymerization temperature are not particularly limited. Although it can select suitably from the kind etc. of the polymerization initiator to be used, generally polymerization temperature is 20-100 degreeC and superposition | polymerization time is 0.5 to 100 hours.

  Furthermore, the polymer obtained by the above method can be adjusted in pH by using a base as a pH adjuster as necessary. Specific examples of the base include sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia, inorganic ammonium compounds, organic amine compounds and the like. The pH range is pH 2-11, preferably pH 3-10, more preferably pH 4-9.

<Method for preparing slurry for battery electrode>
The method for preparing the battery electrode slurry is not particularly limited, and the positive electrode active material or the negative electrode active material, the binder composition of the present invention, the thickener, the conductive auxiliary agent, water and the like are used in a normal stirrer, disperser, kneader, What is necessary is just to disperse | distribute using a planetary ball mill, a homogenizer, etc. In order to increase the efficiency of dispersion, heating may be performed within a range that does not affect the material.

  The water used when preparing the slurry for battery electrodes using the binder composition of this invention is not specifically limited, The water generally used can be used. Specific examples thereof include tap water, distilled water, ion exchange water, and ultrapure water. Among these, distilled water, ion exchange water, and ultrapure water are preferable.

  In order to improve the applicability of the battery electrode slurry, a dispersant may be added in advance to the binder composition containing the polymer or added to the battery electrode slurry as necessary. If it is a dispersing agent, a kind and usage-amount will not be specifically limited, The dispersing agent generally used can be freely used in arbitrary quantity.

In order to improve the applicability of the battery electrode slurry, an antifoaming agent may be added in advance to the binder composition containing the polymer, or may be added to the battery electrode slurry. When an antifoaming agent is added, the dispersibility of each component is improved when the slurry for the battery electrode is prepared, the coating properties of the slurry are improved, and it is possible to prevent bubbles from remaining in the electrode and causing defects, resulting in the battery Yield during manufacturing can be improved. As the antifoaming agent, an antifoaming agent containing no metal atom is preferable, and examples thereof include a silicone-based antifoaming agent, a mineral oil-based antifoaming agent, and a polyether-based antifoaming agent. Silicone and mineral oil defoamers are preferred.
Examples of the silicone-based antifoaming agent include dimethylsilicone-based, methylphenylsilicone-based, and methylvinylsilicone-based antifoaming agents, preferably dimethylsilicone-based. Moreover, it can be used as an emulsion type antifoaming agent formed by dispersing an antifoaming agent in water together with a surfactant. These antifoaming agents can be used alone or in admixture of two or more.

  The solid content concentration of the slurry composition using the binder composition for battery electrodes of the present invention is 10 to 90% by weight, preferably 20 to 85% by weight, and more preferably 30 to 80% by weight.

  The ratio of the polymer amount in the solid content of the slurry composition using the binder composition for battery electrodes of the present invention is 0.1 to 15% by weight, preferably 0.2 to 10% by weight, more preferably 0.00. 3-7% by weight.

<Method for producing battery electrode>
The method for producing the battery electrode is not particularly limited, and a general method is used. The battery electrode slurry (coating solution) is uniformly applied to an appropriate thickness on the surface of the current collector (metal electrode substrate) by a doctor blade method, an applicator method, a silk screen method, or the like.

  For example, in the doctor blade method, a battery electrode slurry is applied to a metal electrode substrate, and then uniformized to an appropriate thickness using a blade having a predetermined slit width. The electrode is dried in hot air at 100 ° C. or in a vacuum at 80 ° C., for example, in order to remove excess organic solvent and water after applying the active material. An electrode material is manufactured by press-molding the dried electrode with a pressing device. You may heat-process again after pressing, and may remove water, a solvent, an emulsifier, etc.

  For example, aluminum is used for the metal electrode substrate of the positive electrode material, but is not limited thereto, and may be nickel, stainless steel, gold, platinum, titanium, or the like.

The positive electrode active material used in the present invention is a lithium metal-containing composite oxide powder having any composition of LiMO ₂ , LiM ₂ O ₄ , Li ₂ MO ₃ , and LiMEO ₄ . Here, M in the formula is mainly composed of a transition metal and includes at least one of Co, Mn, Ni, Cr, Fe, and Ti. M is made of a transition metal, but Al, Ga, Ge, Sn, Pb, Sb, Bi, Si, P, B, etc. may be added in addition to the transition metal. E contains at least one of P and Si. The particle diameter of the positive electrode active material is preferably 50 μm or less, more preferably 20 μm or less. These active materials have an electromotive force of 3 V (vs. Li / Li +) or more.

  Specific examples of the positive electrode active material include lithium cobaltate, lithium nickelate, nickel / manganese / lithium cobaltate (ternary system), spinel type lithium manganate, and lithium iron phosphate.

  For example, copper is used for the metal electrode substrate of the negative electrode material, but is not limited thereto, and may be nickel, stainless steel, gold, platinum, titanium, or the like.

  The negative electrode active material used in the present invention is a carbon material (natural graphite, artificial graphite, amorphous carbon, etc.) having a structure (porous structure) capable of occluding and releasing lithium ions, or occluding and releasing lithium ions. It is a powder made of a metal such as lithium, aluminum-based compound, tin-based compound, silicon-based compound, and titanium-based compound. The particle diameter is preferably from 10 nm to 100 μm, more preferably from 20 nm to 20 μm. Moreover, you may use as a mixed active material of a metal and a carbon material. It is preferable to use a negative electrode active material having a porosity of about 70%.

  Specific examples of the conductive assistant include conductive carbon black such as graphite, furnace black, acetylene black, and ketjen black, carbon fiber such as carbon nanotube, or metal powder. These conductive aids may be used alone or in combination of two or more.

<Battery manufacturing method>
The manufacturing method of the battery using the electrode of this invention, especially a secondary battery is not specifically limited, It is comprised with a positive electrode, a negative electrode, a separator, electrolyte solution, and an electrical power collector, and is manufactured by a well-known method. For example, in the case of a coin-type lithium ion secondary battery, a positive electrode, a separator, and a negative electrode are inserted into an outer can. This is impregnated with an electrolytic solution. Then, it joins with a sealing body by tab welding etc., a sealing body is enclosed, and a storage battery is obtained by crimping. The shape of the battery is not limited, but examples include a coin type, a cylindrical type, and a sheet type, and a structure in which two or more batteries are stacked may be used.

  As the separator, a positive electrode and a negative electrode are directly contacted to prevent short circuit in the battery, and a known material can be used. Specifically, it is made of a porous polymer film such as polyolefin or paper. As the porous polymer film, a film such as polyethylene or polypropylene is preferable because it is not affected by the electrolytic solution.

The electrolytic solution is a solution comprising an electrolyte lithium salt compound and an aprotic organic solvent as a solvent. As the electrolyte lithium salt compound, a lithium salt compound having a wide potential window, which is generally used in lithium ion batteries, is used. For example, LiBF ₄ , LiPF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN [CF ₃ SC (C ₂ F ₅ SO ₂ ) ₃ ] _{2 and the} like, but are not limited thereto. These may be used alone or in combination of two or more.

  As aprotic organic solvents, propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, γ-butyrolactone, tetrahydrofuran, 1,3-dioxolane, Linear ethers such as dipropyl carbonate, diethyl ether, sulfolane, methyl sulfolane, acetonitrile, propyl nitrile, anisole, acetic acid ester, propionic acid ester, diethyl ether can be used. Good.

  Moreover, room temperature molten salt can be used as a solvent. The room temperature molten salt refers to a salt that is at least partially in a liquid state at room temperature, and the room temperature refers to a temperature range in which the power supply is assumed to normally operate. The temperature range in which the power supply is assumed to normally operate has an upper limit of about 120 ° C. and in some cases about 60 ° C., and a lower limit of about −40 ° C. and in some cases about −20 ° C.

  The room temperature molten salt is also called an ionic liquid, and pyridine, aliphatic amine and alicyclic amine quaternary ammonium organic cations are known. Examples of the quaternary ammonium organic cation include imidazolium ions such as dialkylimidazolium and trialkylimidazolium, tetraalkylammonium ions, alkylpyridinium ions, pyrazolium ions, pyrrolidinium ions, and piperidinium ions. In particular, an imidazolium cation is preferable.

  Examples of tetraalkylammonium ions include, but are not limited to, trimethylethylammonium ion, trimethylethylammonium ion, trimethylpropylammonium ion, trimethylhexylammonium ion, tetrapentylammonium ion, and triethylmethylammonium ion. is not.

  Examples of the alkyl pyridinium ion include N-methyl pyridinium ion, N-ethyl pyridinium ion, N-propyl pyridinium ion, N-butyl pyridinium ion, 1-ethyl-2methyl pyridinium ion, 1-butyl-4-methyl. Examples thereof include, but are not limited to, pyridinium ions and 1-butyl-2,4 dimethylpyridinium ions.

  Examples of the imidazolium cation include 1,3-dimethylimidazolium ion, 1-ethyl-3-methylimidazolium ion, 1-methyl-3-ethylimidazolium ion, 1-methyl-3-butylimidazolium ion, 1- Butyl-3-methylimidazolium ion, 1,2,3-trimethylimidazolium ion, 1,2-dimethyl-3-ethylimidazolium ion, 1,2-dimethyl-3-propylimidazolium ion, 1-butyl- Examples include 2,3-dimethylimidazolium ion, but are not limited thereto.

  In addition, the normal temperature molten salt which has these cations may be used independently, or may mix and use 2 or more types.

Various additives can be used in the electrolytic solution as necessary. Examples of flame retardants and flame retardants include brominated epoxy compounds, phosphazene compounds, tetrabromobisphenol A, halides such as chlorinated paraffin, antimony trioxide, antimony pentoxide, aluminum hydroxide, magnesium hydroxide, phosphate esters, Examples thereof include polyphosphate and zinc borate. Examples of the negative electrode surface treatment agent include vinylene carbonate, fluoroethylene carbonate, and polyethylene glycol dimethyl ether. Examples of the positive electrode surface treatment agent include inorganic compounds such as carbon and metal oxides (such as MgO and ZrO ₂ ), and organic compounds such as ortho-terphenyl. Examples of the overcharge inhibitor include biphenyl and 1- (p-tolyl) adamantane.

  Specific modes for carrying out the present invention will be described below with reference to examples. However, the present invention is not limited to the following examples without departing from the gist thereof.

  In this example, an electrode and a coin battery were prepared using the binder composition for battery electrodes of the present invention, a peel test as an evaluation of the electrode, an internal resistance measurement and a charge / discharge cycle characteristic test as an evaluation of the coin battery as follows. I went there.

[Evaluation of physical properties of fabricated electrodes]
As an evaluation of the physical properties of the produced electrodes, a bending test and a binding test were performed. The evaluation results are summarized in Table 1.
<Bending test>
The bending test was performed by a mandrel bending test. Specifically, the electrode is cut into a width of 3 cm and a length of 8 cm, and 180 ° with a stainless steel rod having a diameter of 2 mm on the base side (the electrode surface faces the outside) at the center (4 cm portion) in the length direction.
The state of the coating film at the bent portion when bent was observed. Measurement is performed 5 times by this method, and the case where the electrode surface is not cracked or peeled off or peeled off from the current collector at all 5 times. The case where one or more cracks or peeling occurs even once. It was evaluated.

<Binding test>
The binding test was performed by a cross cut test. Specifically, the electrode is cut to a width of 3 cm × length of 4 cm, and a grid pattern is cut with a cutter knife so that one side of one square is 1 mm, and from 25 squares of vertical 5 squares × horizontal 5 squares. When a tape (adhesive tape: manufactured by Nichiban) was applied to the grid and the tape was peeled off at a stretch with the electrode fixed, the number of cells remaining without peeling from the electrode was measured. The test was performed 5 times, and the average value was obtained.

[Characteristic evaluation of the fabricated battery]
As characteristic evaluation of the produced coin battery, the internal resistance was measured by charging and discharging, and a charge / discharge cycle characteristic test was performed using a charging / discharging device, and a capacity retention rate was obtained. The evaluation results are summarized in Table 2.
<Measurement of internal resistance>
The produced lithium ion battery was charged to 4.2 V by constant current-constant voltage charging. The end current was equivalent to 2C. After charging, the battery was paused for 10 minutes. Next, constant current discharge was performed, and the internal resistance R (Ω) = ΔE / I of the lithium ion battery was measured from the current value I (mA) and the voltage drop ΔE (mV) after 10 seconds.

<Capacity maintenance rate>
When spinel type lithium manganate is used as the positive electrode active material, the charge and discharge device manufactured by Toyo System Co., Ltd. is used for the electrochemical characteristics, with 4.3 V as the upper limit and 3.0 V as the lower limit. Test conditions (C / 8) in which predetermined charging and discharging can be performed over time, the charge / discharge cycle characteristics of the positive electrode were evaluated by constant current application at 1C for the fourth and subsequent times. The test temperature was a 25 ° C. environment. The capacity retention rate was evaluated by the ratio between the capacity after 100 cycles of charge and discharge and the capacity at the fourth cycle.

<Synthesis example of binder composition>
[Exemplary Synthesis Example 1 of Binder Composition]
In a reaction vessel equipped with a stirrer, 30 parts by weight of polyethylene glycol monoacrylate (manufactured by NOF: BLEMMER AE-400), 55 parts by weight of 2-ethylhexyl acrylate, 2 parts by weight of acrylic acid, trimethylolpropane triacrylate (manufactured by Shin-Nakamura Chemical) : 13 parts by weight of A-TMPT), 1 part by weight as a solid content of sodium lauryl sulfate (Kao: Emar 10G) as an emulsifier, and 2 parts by weight as an active ingredient of polyoxyethylene polyoxypropylene glycol (manufactured by NOF: Pronon 208) Part, 150 parts by weight of ion-exchanged water and 0.1 part by weight of ammonium persulfate as a polymerization initiator, sufficiently emulsified using a homogenizer, heated to 60 ° C. in a nitrogen atmosphere, polymerized for 5 hours, and then cooled. did. After cooling, the pH of the polymerization solution was adjusted to 8.2 using a 28% aqueous ammonia solution to obtain Binder A (polymerization conversion rate 99% or more) (solid content concentration 40 wt%). The average particle size of the obtained polymer was 0.237 μm.

[Exemplary Synthesis Example 2 of Binder Composition]
In a reaction vessel equipped with a stirrer, 47 parts by weight of methyl methacrylate, 33 parts by weight of polypropylene glycol monoacrylate (manufactured by NOF: Blemmer AP-400), 1 part by weight of acrylic acid, 4 parts by weight of methacrylic acid, trimethylolpropane triacrylate (Shin-Nakamura Chemical Co., Ltd .: A-TMPT) 15 parts by weight, polyoxyalkylene alkenyl ether ammonium sulfate aqueous solution (Kao: PD-104) as an emulsifier, 2 parts by weight, polyoxyethylene polyoxypropylene glycol (manufactured by NOF Corporation) : 1 part by weight as an active ingredient of Pronon 235), 150 parts by weight of ion-exchanged water and 0.1 part by weight of ammonium persulfate as a polymerization initiator, sufficiently emulsified using a homogenizer, and then heated to 60 ° C. in a nitrogen atmosphere. The mixture was heated and polymerized for 5 hours, and then cooled. After cooling, the polymerization solution was adjusted to pH 8.1 using a 28% aqueous ammonia solution to obtain Binder B (polymerization conversion rate 99% or more) (solid content concentration 41 wt%). The average particle diameter of the obtained polymer was 0.215 μm.

[Exemplary Synthesis Example 3 of Binder Composition]
In a reaction vessel equipped with a stirrer, 58.5 parts by weight of methyl methacrylate, 19 parts by weight of polypropylene glycol monoacrylate (manufactured by NOF: Blenmer AP-400), 1.5 parts by weight of acrylic acid, 4 parts by weight of methacrylic acid, tri 17 parts by weight of methylolpropane triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd .: A-TMPT), 3 parts by weight as a solid content of sodium lauryl sulfate (Kao: Emar 10G) as an emulsifier, polyoxyethylene polyoxypropylene glycol (manufactured by NOF: 1 part by weight as an active ingredient of Pronon 208), 150 parts by weight of ion exchange water and 0.1 part by weight of ammonium persulfate as a polymerization initiator were sufficiently emulsified using a homogenizer, and then added to 60 ° C. in a nitrogen atmosphere. Warm and polymerize for 5 hours, then cool. After cooling, the polymerization solution was adjusted to pH 8.1 using a 28% aqueous ammonia solution to obtain binder C (polymerization conversion rate 99% or more) (solid content concentration 40 wt%). The average particle size of the obtained polymer was 0.153 μm.

[Exemplary Synthesis Example 4 of Binder Composition]
In a reaction vessel equipped with a stirrer, 70 parts by weight of methyl methacrylate, 5 parts by weight of polyethylene glycol monomethacrylate (manufactured by NOF: Blenmer AE-90), 1 part by weight of acrylic acid, 4 parts by weight of methacrylic acid, trimethylolpropane tri 20 parts by weight of acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd .: A-TMPT), 1 part by weight as a solid content of an aqueous solution of polyoxyalkylene alkenyl ether ammonium sulfate (manufactured by Kao: PD-104) as an emulsifier, polyoxyethylene polyoxypropylene glycol (NOF) Manufactured by Pronon 208), 3 parts by weight as active ingredients, 150 parts by weight of ion-exchanged water and 0.1 parts by weight of ammonium persulfate as a polymerization initiator were sufficiently emulsified using a homogenizer, and then at 60 ° C. in a nitrogen atmosphere. And polymerized for 5 hours, and then cooled. After cooling, the polymerization solution was adjusted to pH 8.1 using a 28% aqueous ammonia solution to obtain binder D (polymerization conversion rate 99% or more) (solid content concentration 40 wt%). The average particle diameter of the obtained polymer was 0.203 μm.

[Exemplary Synthesis Example 5 of Binder Composition]
In a reaction vessel equipped with a stirrer, 57 parts by weight of methyl methacrylate, 20 parts by weight of polyethylene glycol monoacrylate (manufactured by NOF: Blemmer AE-200), 1.5 parts by weight of acrylic acid, 4.5 parts by weight of methacrylic acid, tri 17 parts by weight of methylolpropane triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd .: A-TMPT), 1 part by weight as a solid content of a sodium lauryl sulfate solution (manufactured by Kao: Emar 2F-30) as an emulsifier, a reactive nonionic surfactant (manufactured by Kao) : 1 part by weight as an active ingredient of Latemul PD-420), 150 parts by weight of ion-exchanged water and 0.1 part by weight of ammonium persulfate as a polymerization initiator, sufficiently emulsified with a homogenizer, and then added in a nitrogen atmosphere to 60 The mixture was heated to 0 ° C., polymerized for 5 hours, and then cooled. After cooling, the polymerization solution was adjusted to pH 8.1 using a 28% aqueous ammonia solution to obtain Binder E (polymerization conversion rate 99% or more) (solid content concentration 41 wt%). The average particle diameter of the obtained polymer was 0.186 μm.

[Comparative Synthesis Example 1 of Binder Composition]
In a reaction vessel equipped with a stirrer, 30 parts by weight of polyethylene glycol monoacrylate (manufactured by NOF: BLEMMER AE-400), 55 parts by weight of 2-ethylhexyl acrylate, 2 parts by weight of acrylic acid, trimethylolpropane triacrylate (manufactured by Shin-Nakamura Chemical) : A-TMPT) 13 parts by weight, 3 parts by weight as solid content of sodium lauryl sulfate (Kao: EMAL 10G) as an emulsifier, 150 parts by weight of ion-exchanged water and 0.1 part by weight of ammonium persulfate as a polymerization initiator, The mixture was sufficiently emulsified using a homogenizer, heated to 60 ° C. under a nitrogen atmosphere, polymerized for 5 hours, and then cooled. After cooling, the pH of the polymerization solution was adjusted to 8.2 using a 28% aqueous ammonia solution to obtain Binder F (polymerization conversion rate 99% or more) (solid content concentration 41 wt%). The average particle size of the obtained polymer was 0.157 μm.

[Comparative Synthesis Example 2 of Binder Composition]
In a reaction vessel equipped with a stirrer, 30 parts by weight of polyethylene glycol monoacrylate (manufactured by NOF: BLEMMER AE-400), 55 parts by weight of 2-ethylhexyl acrylate, 2 parts by weight of acrylic acid, trimethylolpropane triacrylate (manufactured by Shin-Nakamura Chemical) : A-TMPT) 13 parts by weight, polyoxyethylene polyoxypropylene glycol (manufactured by NOF Corporation: Pronon 208) as an emulsifier as an active ingredient 5 parts by weight, ion-exchanged water 150 parts by weight, and polymerization initiator 0.1 ammonium persulfate After adding a weight part and fully emulsifying using a homogenizer, it heated at 60 degreeC under nitrogen atmosphere, superposed | polymerized for 5 hours, and cooled after that. After cooling, the pH of the polymerization solution was adjusted to 8.2 using a 28% aqueous ammonia solution to obtain a binder G (polymerization conversion rate of 99% or more) (solid content concentration 39 wt%). The average particle diameter of the obtained polymer was 0.258 μm.

[Comparative Synthesis Example 3 of Binder Composition]
In a reaction vessel equipped with a stirrer, 80 parts by weight of methyl methacrylate, 3 parts by weight of acrylic acid, 5 parts by weight of methacrylic acid, 12 parts by weight of trimethylolpropane triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd .: A-TMPT), sodium lauryl sulfate as an emulsifier 2 parts by weight as active ingredients of Kao (Emal 10G), 150 parts by weight of ion-exchanged water and 0.1 part by weight of ammonium persulfate as a polymerization initiator were sufficiently emulsified using a homogenizer, and then in a nitrogen atmosphere. The mixture was heated to 60 ° C., polymerized for 5 hours, and then cooled. After cooling, the pH of the polymerization solution was adjusted to 8.2 using a 28% aqueous ammonia solution to obtain binder H (polymerization conversion rate 99% or more) (solid content concentration 39 wt%). The average particle diameter of the obtained polymer was 0.145 μm.

<Example of electrode production>
[Example 1 of electrode production]
Add 95 parts by weight of spinel type lithium manganate as a positive electrode active material, add 3 parts by weight of acetylene black as a conductive additive, and add 2 parts by weight as a solid content of the binder A obtained in Example 1 of the binder composition. Water was added so that the solid content concentration of the mixture became 55% by weight and mixed well using a planetary mill to obtain a positive electrode slurry.
The obtained positive electrode slurry was applied onto a 20 μm thick aluminum current collector using a 100 μm gap Baker type applicator, dried at 110 ° C. in a vacuum state for 12 hours or more, and then pressed with a roll press machine. A positive electrode having a thickness of 32 μm was produced. The evaluation results of the bending test and the binding test are shown in Example 1 of Table 1.

[Example 2 of electrode production]
A positive electrode was produced in the same manner as in Example 1 for producing an electrode electrode, except that the binder B obtained in Example 2 of the binder composition was used. The thickness of the positive electrode obtained was 33 μm. The evaluation results of the bending test and the binding property test are shown in Example 2 of Table 1.

[Example 3 of electrode production]
A positive electrode was produced in the same manner as in Example 1 for producing electrodes except that the binder C obtained in Example 3 for binder composition was used. The thickness of the positive electrode obtained was 32 μm. The evaluation results of the bending test and the binding test are shown in Example 3 in Table 1.

[Example 4 of electrode production]
A positive electrode was produced in the same manner as in Example 1 for producing an electrode except that the binder D obtained in Example 4 of the binder composition was used. The thickness of the positive electrode obtained was 32 μm. The evaluation results of the bending test and the binding test are shown in Example 4 of Table 1.

[Example 5 of electrode production]
A positive electrode was produced in the same manner as in Example 1 for producing electrodes except that the binder E obtained in Example 5 for binder composition was used. The thickness of the positive electrode obtained was 33 μm. The evaluation results of the bending test and the binding test are shown in Example 5 of Table 1.

[Electrode Comparative Production Example 1]
A positive electrode was produced in the same manner as in Example 1 of production of the electrode except that the binder F obtained in Comparative Synthesis Example 1 of the binder composition was used. The thickness of the positive electrode obtained was 32 μm. The evaluation results of the bending test and the binding test are shown in Comparative Example 1 in Table 1.

[Electrode Comparison Preparation Example 2]
A positive electrode was produced in the same manner as in Example 1 for producing an electrode except that the binder G obtained in Comparative Synthesis Example 2 for the binder composition was used. The thickness of the positive electrode obtained was 33 μm. The evaluation results of the bending test and the binding test are shown in Comparative Example 2 in Table 1.

[Electrode Comparative Production Example 3]
A positive electrode was produced in the same manner as in Example 1 of production of the electrode except that the binder H obtained in Comparative Synthesis Example 3 of the binder composition was used. The thickness of the positive electrode obtained was 32 μm. The evaluation results of the bending test and the binding test are shown in Comparative Example 2 in Table 1.

<Example of battery production>
[Example of coin battery production 1]
In the glove box substituted with argon gas, the positive electrode obtained in Example 1 of electrode fabrication, a 18 μm thick polypropylene / polyethylene / polypropylene porous membrane as the separator, and a 300 μm thick metallic lithium foil as a counter electrode are attached. The combined laminate is sufficiently impregnated with 1 mol / L of lithium hexafluorophosphate ethylene carbonate, ethyl methyl carbonate, and diethyl carbonate (volume ratio 3: 5: 2) as an electrolytic solution, and caulked to test 2032 type. A coin battery was manufactured. The measured value of the internal resistance using the prototype coin battery and the evaluation result of the capacity maintenance rate after 100 cycles are shown in Example 1 of Table 2.

[Example of coin battery production 2]
A coin battery was fabricated in the same manner as in the electrode fabrication example 1 except that the positive electrode obtained in the electrode fabrication example 2 was used. Table 2 shows the measured value of the internal resistance using the prototype coin battery and the evaluation result of the capacity retention rate after 100 cycles.

[Example 3 of coin battery production]
A coin battery was produced in the same manner as in Example 1 of electrode production except that the positive electrode obtained in Example 3 of electrode production was used. Table 3 shows the measured value of the internal resistance using the prototype coin battery and the evaluation result of the capacity retention rate after 100 cycles.

[Example of coin battery production 4]
A coin battery was fabricated in the same manner as in the electrode fabrication example 1 except that the positive electrode obtained in the electrode fabrication example 4 was used. The measured value of the internal resistance using the prototype coin battery and the evaluation result of the capacity maintenance rate after 100 cycles are shown in Example 4 of Table 2.

[Example 5 of coin battery production]
A coin battery was fabricated in the same manner as in the electrode fabrication example 1 except that the positive electrode obtained in the electrode fabrication example 5 was used. The measured value of the internal resistance and the evaluation result of the capacity retention rate after 100 cycles are shown in Example 5 of Table 2.

[Comparison example 1 of coin battery]
A coin battery was produced in the same manner as in Example 1 of electrode production except that the positive electrode obtained in Comparative Production Example 1 of electrode was used. Comparative Example 1 in Table 2 shows the measured value of the internal resistance using the prototype coin cell and the evaluation result of the capacity retention rate after 100 cycles.

[Comparison example 2 of coin battery]
A coin battery was produced in the same manner as in Example 1 of electrode production except that the positive electrode obtained in Comparative Production Example 2 of electrode was used. Comparative Example 2 in Table 2 shows the measured value of the internal resistance using the prototype coin cell and the evaluation result of the capacity retention rate after 100 cycles.

[Comparison example 3 of coin battery]
A coin battery was produced in the same manner as in Example 1 of electrode production except that the positive electrode obtained in Comparative Production Example 3 of electrode was used. The measured value of the internal resistance using the prototype coin battery and the evaluation result of the capacity retention rate after 100 cycles are shown in Comparative Example 3 of Table 2.

Tables 1 and 2 show the results of Examples and Comparative Examples.

Examples 1 to 5 which are lithium ion batteries using the binder composition for battery electrodes of the present invention are superior in binding properties compared to Comparative Examples 1 to 3, and are particularly superior to Comparative Example 3. The binding property is improved. Moreover, compared with Comparative Examples 1-3, the internal resistance of a coin battery was low, and as a result, it was shown that it is very excellent also in the capacity maintenance rate after 100 cycles.

  The binder composition for battery electrodes of the present invention has the advantage that it is an aqueous system with a high binding force and a small environmental load, and that the performance does not affect the temperature. From small batteries such as mobile phones, laptop computers, and electronic devices such as camcorders using the binder composition for battery electrodes of the present invention, to large-sized batteries such as electric vehicles and hybrid electric vehicles, and storage batteries for household power storage. It can be suitably used for battery applications.

Claims (10)

(A) a structural unit derived from a (meth) acrylic monomer;
(B) A polymer electrode comprising a structural unit derived from a polyfunctional (meth) acrylate monomer, and (C) a battery electrode comprising a nonionic surfactant and an anionic surfactant as an emulsifier Binder composition.   The (A) (meth) acrylic monomer is (A-1) a (meth) acrylate monomer having a hydroxyl group, (A-2) a (meth) acrylate monomer, and (A-3) a (meth) acrylic acid monomer. The battery electrode binder composition according to claim 1.   (A-1) The binder composition for battery electrodes according to claim 2, wherein the (meth) acrylic monomer having a hydroxyl group is an alkylene glycol mono (meth) acrylate monomer having a molecular weight of 100 to 1,000.   (B) Polyfunctional (meth) acrylate monomer is 2-5 functional (meth) acrylate, The binder composition for battery electrodes in any one of Claims 1-3 characterized by the above-mentioned.   The anionic surfactant is an anionic surfactant selected from sulfate ester type, carboxylic acid type, sulfonic acid type, and phosphate ester type, and the nonionic surfactant is a polyoxyalkylene type nonionic surfactant. The binder composition for battery electrodes according to claim 1, wherein the binder composition is for battery electrodes. 6. The battery electrode according to claim 1, wherein the content of the anionic surfactant and the nonionic surfactant is 0.01 to 10% by weight with respect to the charged monomer amount. Binder composition. The battery electrode binder composition according to any one of claims 1 to 6, wherein the content ratio of the anionic surfactant to the nonionic surfactant is 1:10 to 10: 1. In water, (A) (meth) acrylic monomer and (B) structural unit derived from polyfunctional (meth) acrylate monomer are polymerized while emulsifying using nonionic surfactant and anionic surfactant. The manufacturing method of the binder composition for battery electrodes obtained. A battery electrode comprising at least the binder composition according to any one of claims 1 to 7, an active material, and a conductive additive. A battery obtained by using the electrode according to claim 9.