WO2015129408A1 - 二次電池多孔膜用バインダー組成物、二次電池多孔膜用スラリー、二次電池用多孔膜及び二次電池 - Google Patents
二次電池多孔膜用バインダー組成物、二次電池多孔膜用スラリー、二次電池用多孔膜及び二次電池 Download PDFInfo
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- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
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- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
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- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/10—Esters
- C08F220/12—Esters of monohydric alcohols or phenols
- C08F220/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
- C08F220/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
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- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/10—Esters
- C08F220/12—Esters of monohydric alcohols or phenols
- C08F220/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
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- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
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- C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
- C08L33/04—Homopolymers or copolymers of esters
- C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
- C08L33/062—Copolymers with monomers not covered by C08L33/06
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- H01M10/00—Secondary cells; Manufacture thereof
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- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
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- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
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- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/403—Manufacturing processes of separators, membranes or diaphragms
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- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/411—Organic material
- H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
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- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
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- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
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- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
- H01M50/491—Porosity
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- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
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- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Definitions
- the present invention relates to a binder composition for a secondary battery porous film, a slurry for a secondary battery porous film, a porous film for a secondary battery, and a secondary battery.
- Lithium ion secondary batteries have been widely used in recent years as power sources for portable devices.
- lithium ion secondary batteries have characteristics such as being small and light, having high energy density, and being capable of repeated charge and discharge, and are expected to expand demand.
- Lithium ion secondary batteries are used in devices such as mobile phones and notebook personal computers, taking advantage of their high energy density.
- Secondary batteries are required to further improve performance in order to improve the performance of the devices used. For example, it is required to improve performance such as the ability to maintain capacity (high temperature cycle characteristics) even when charging and discharging are repeated in a high temperature environment.
- a separator is provided between a positive electrode and a negative electrode in order to improve performance.
- a porous film obtained by applying a slurry layer containing non-conductive particles and a binder to a substrate to form a layer and drying the layer is known.
- a so-called aqueous slurry prepared using water as a solvent for reducing the environmental load is becoming widespread.
- various polymers are used as a binder as a component of a slurry for forming a porous film (Patent Documents 1 and 2).
- Such a slurry makes it possible to easily produce a high-quality porous film by making the coating property favorable by setting the physical properties such as the viscosity within a preferable range.
- the property of maintaining a stable state for a long time without deterioration such as separation of solid content is required.
- a cellulose polymer such as carboxymethyl cellulose (CMC) is widely added to the slurry.
- an object of the present invention is to provide a secondary battery that can be easily manufactured and improved in performance such as high-temperature cycle characteristics; a secondary battery that can improve the performance of such a secondary battery and can be easily manufactured
- a porous membrane for a secondary battery that can be used as a material for such a porous membrane and is easy to apply and excellent in storage stability; and can be used as a material for such a slurry for a porous membrane; It is providing the binder composition for secondary battery porous membranes which is excellent in storage stability.
- the present inventor has studied to achieve the above object.
- the present inventor has studied to employ a specific polycarboxylic acid as a polymer to be added to the aqueous slurry for a porous membrane.
- a specific polycarboxylic acid as a polymer to be added to the aqueous slurry for a porous membrane.
- the storage stability of the slurry is poor.
- the specific polycarboxylic acid has high storage stability in an acidic state, while it can impart an appropriate viscosity to a slurry in an alkaline state. did.
- the present inventor further prepared such a specific polycarboxylic acid as an acidic porous membrane binder composition, and mixed it with a dispersion of non-conductive particles during use to obtain an alkaline slurry. It was found that both high storage stability of products and moderate viscosity at the time of use can be enjoyed, and the present invention was completed. That is, according to the present invention, the following [1] to [7] are provided.
- a binder composition for a secondary battery porous membrane comprising a polycarboxylic acid and water,
- the polycarboxylic acid contains 20% by mass to 50% by mass of a carboxylic acid group-containing monomer unit,
- the polycarboxylic acid is water-insoluble at pH 6.5 or lower, water-soluble at pH 8 or higher,
- the binder composition for secondary battery porous membranes whose pH of the binder composition for secondary battery porous membranes is 6.5 or less.
- the alkyl (meth) acrylate unit includes an alkyl (meth) acrylate unit (U1) having an alkyl group having 1 to 3 carbon atoms and an alkyl (meth) acrylate unit (U2) having an alkyl group having 4 to 6 carbon atoms.
- a slurry for a secondary battery porous membrane containing non-conductive particles, polycarboxylic acid and water contains 20% by mass to 50% by mass of a carboxylic acid group-containing monomer unit, The polycarboxylic acid is water-insoluble at pH 6.5 or lower, water-soluble at pH 8 or higher, A slurry for a secondary battery porous membrane, wherein the pH of the slurry for a secondary battery porous membrane is more than 7.0.
- a porous membrane for a secondary battery which is formed by forming a layer of the slurry for a secondary battery porous membrane according to [5] and drying the layer.
- a secondary battery comprising the porous membrane for a secondary battery according to [6].
- the binder composition for a secondary battery porous membrane of the present invention has high storage stability, and the secondary battery porous membrane of the present invention manufactured using the same is easy to apply and has improved performance such as high-temperature cycle characteristics. It is possible to easily manufacture a porous film for a secondary battery that can provide the secondary battery.
- (meth) acryl means either or both of acrylic and methacrylic.
- (meth) acrylic acid means acrylic acid, methacrylic acid or a combination thereof.
- (meth) acrylate means acrylate, methacrylate, or a combination thereof.
- the polycarboxylic acid may be water-soluble or non-water-soluble depending on pH. Therefore, the “aqueous solution” and “aqueous dispersion” of the polycarboxylic acid in the following description are described as “aqueous solution”.
- a water-insoluble polycarboxylic acid may be dispersed therein, and a water-soluble polycarboxylic acid may be dissolved in what is referred to as an “aqueous dispersion”.
- binder composition for porous film contains a specific polycarboxylic acid and water. This specific polycarboxylic acid may be referred to as polycarboxylic acid (A) below.
- the polycarboxylic acid (A) is a polymer containing a predetermined proportion of carboxylic acid group-containing monomer units.
- the polycarboxylic acid (A) binds the nonconductive particles by interposing between the nonconductive particles in the porous film, and between the nonconductive particles and the separator substrate or the electrode plate. By intervening, the effect of binding the porous film and the separator substrate or the electrode plate can be achieved.
- the carboxylic acid group-containing monomer unit in the polycarboxylic acid (A) refers to a structural unit having a structure formed by polymerizing a carboxylic acid group-containing monomer.
- the carboxylic acid group-containing monomer may be a compound having a —COOH group (carboxylic acid group) and a group capable of undergoing a polymerization reaction.
- a monomer capable of generating a carboxylic acid group by hydrolysis can also be used as the carboxylic acid group-containing monomer.
- Specific examples of such carboxylic acid group-containing monomers include acid anhydrides that can generate carboxylic acid groups by hydrolysis.
- Examples of the carboxylic acid group-containing monomer include the following ethylenically unsaturated carboxylic acid monomers.
- Examples of the ethylenically unsaturated carboxylic acid monomer include ethylenically unsaturated monocarboxylic acid and derivatives thereof, ethylenically unsaturated dicarboxylic acid and acid anhydrides thereof, and derivatives thereof.
- Examples of the ethylenically unsaturated monocarboxylic acid include acrylic acid, methacrylic acid, crotonic acid and the like.
- Examples of derivatives of ethylenically unsaturated monocarboxylic acids include 2-ethylacrylic acid, isocrotonic acid, ⁇ -acetoxyacrylic acid, ⁇ -trans-aryloxyacrylic acid, ⁇ -chloro- ⁇ -E-methoxyacrylic acid, Examples thereof include ⁇ -diaminoacrylic acid.
- Examples of the ethylenically unsaturated dicarboxylic acid include maleic acid, fumaric acid, itaconic acid and the like.
- Examples of the acid anhydride of the ethylenically unsaturated dicarboxylic acid include maleic anhydride, acrylic anhydride, methyl maleic anhydride, dimethyl maleic anhydride and the like.
- Examples of ethylenically unsaturated dicarboxylic acid derivatives include methyl maleic acid, dimethyl maleic acid, phenyl maleic acid, chloromaleic acid, dichloromaleic acid, fluoromaleic acid and other maleic acids; methylallyl maleate, maleic acid Examples thereof include maleic acid esters such as diphenyl acid, nonyl maleate, decyl maleate, dodecyl maleate, octadecyl maleate and fluoroalkyl maleate.
- ethylenically unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid are preferable because the dispersibility of the polycarboxylic acid (A) in water can be further improved.
- one type of ethylenically unsaturated carboxylic acid monomer may be used alone, or two or more types may be used in combination at any ratio.
- the ratio of the carboxylic acid group-containing monomer unit in the polycarboxylic acid (A) is 20% by weight or more, preferably 25% by weight or more, more preferably 28% by weight or more, while 50% by weight or less, preferably 45%. % By weight or less, more preferably 40% by weight or less.
- the ratio of the carboxylic acid group-containing monomer unit in the polycarboxylic acid (A) By setting the ratio of the carboxylic acid group-containing monomer unit in the polycarboxylic acid (A) to the upper limit or less, flexibility can be imparted to the porous film, and the adhesion strength between the porous film and the substrate can be increased. .
- the polycarboxylic acid (A) preferably contains an alkyl (meth) acrylate unit.
- the alkyl (meth) acrylate unit refers to a structural unit having a structure formed by polymerizing alkyl (meth) acrylate. Examples of the alkyl (meth) acrylate include alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms.
- the alkyl (meth) acrylate is preferably an alkyl (meth) acrylate having an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl (meth) acrylate having an alkyl group having 1 to 6 carbon atoms. More preferably.
- One or more of these alkyl (meth) acrylates can be used in combination as an alkyl (meth) acrylate for polymerization of the polycarboxylic acid (A).
- alkyl (meth) acrylate examples include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, and 2-ethylhexyl acrylate.
- Alkyl acrylates such as nonyl acrylate, decyl acrylate, lauryl acrylate, n-tetradecyl acrylate, stearyl acrylate; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, pentyl methacrylate, Hexyl methacrylate, heptyl methacrylate DOO, octyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, decyl methacrylate, lauryl methacrylate, n- tetradecyl methacrylate, and alkyl methacrylates such as stearyl methacrylate. Moreover, these may use only 1 type and may be used combining two or more types by arbitrary ratios.
- the ratio of the alkyl (meth) acrylate unit in the polycarboxylic acid (A) is preferably 50% by weight or more, more preferably 55% by weight or more, and even more preferably 60% by weight or more.
- the upper limit of the ratio of the alkyl (meth) acrylate unit in the polycarboxylic acid (A) is 80% by weight or less.
- the polycarboxylic acid (A) comprises an alkyl (meth) acrylate unit (U1) having an alkyl group having 1 to 3 carbon atoms and an alkyl group having 4 to 6 carbon atoms as the alkyl (meth) acrylate unit. And an alkyl (meth) acrylate unit (U2).
- U1 alkyl (meth) acrylate unit having an alkyl group having 1 to 3 carbon atoms and an alkyl group having 4 to 6 carbon atoms as the alkyl (meth) acrylate unit.
- the storage stability of the binder becomes excellent by combining the unit (U1) and the unit (U2).
- the weight ratio U1 / U2 between the units (U1) and units (U2) in the polycarboxylic acid is preferably 1.0 or more, more preferably 2.0 or more, and even more preferably 2.5 or more. On the other hand, it is preferably 10.0 or less, more preferably 7.0 or less, even more preferably 6.0 or less, and particularly preferably 5.0 or less.
- the weight ratio U1 / U2 between the unit (U1) and the unit (U2) in the polycarboxylic acid is not less than the lower limit, the polycarboxylic acid (A) can be easily solubilized, and the slurry for the porous membrane can be obtained.
- the polycarboxylic acid (A) can contain a crosslinkable monomer unit.
- a crosslinkable monomer unit refers to a structural unit having a structure formed by polymerizing a crosslinkable monomer.
- the crosslinkable monomer represents a monomer that can form a crosslinked structure by polymerization.
- a monomer having heat crosslinkability is usually mentioned. More specifically, a monofunctional monomer having a thermally crosslinkable crosslinkable group and one olefinic double bond per molecule; a multifunctional having two or more olefinic double bonds per molecule Monomer.
- thermally crosslinkable groups examples include epoxy groups, N-methylolamide groups, oxetanyl groups, oxazoline groups, and combinations thereof.
- an epoxy group is more preferable in terms of easy adjustment of crosslinking and crosslinking density.
- crosslinkable monomer having an epoxy group as a thermally crosslinkable group and having an olefinic double bond examples include vinyl glycidyl ether, allyl glycidyl ether, butenyl glycidyl ether, o-allylphenyl glycidyl.
- Unsaturated glycidyl ethers such as ether; butadiene monoepoxide, chloroprene monoepoxide, 4,5-epoxy-2-pentene, 3,4-epoxy-1-vinylcyclohexene, 1,2-epoxy-5,9-cyclododecadiene Monoepoxides of dienes or polyenes such as; alkenyl epoxides such as 3,4-epoxy-1-butene, 1,2-epoxy-5-hexene, 1,2-epoxy-9-decene; and glycidyl acrylate, glycidyl methacrylate, Glycidyl crotonate, Unsaturated carboxylic acids such as glycidyl-4-heptenoate, glycidyl sorbate, glycidyl linoleate, glycidyl-4-methyl-3-pentenoate, glycidyl este
- crosslinkable monomer having an N-methylolamide group as a thermally crosslinkable group and having an olefinic double bond have a methylol group such as N-methylol (meth) acrylamide (meta ) Acrylamides.
- crosslinkable monomer having an oxetanyl group as a thermally crosslinkable group and having an olefinic double bond examples include 3-((meth) acryloyloxymethyl) oxetane, 3-((meth) Acryloyloxymethyl) -2-trifluoromethyloxetane, 3-((meth) acryloyloxymethyl) -2-phenyloxetane, 2-((meth) acryloyloxymethyl) oxetane, and 2-((meth) acryloyloxymethyl) ) -4-Trifluoromethyloxetane.
- crosslinkable monomer having an oxazoline group as a heat crosslinkable group and having an olefinic double bond examples include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2- Oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline.
- crosslinkable monomers having two or more olefinic double bonds per molecule examples include allyl (meth) acrylate, ethylene di (meth) acrylate, diethylene glycol di (meth) acrylate, and triethylene glycol di (meth).
- crosslinkable monomer ethylene dimethacrylate, allyl glycidyl ether, and glycidyl methacrylate are particularly preferable as the crosslinkable monomer.
- crosslinked monomer unit may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- the proportion of the crosslinkable monomer unit in the polycarboxylic acid (A) is preferably 0.1% by weight or more, more preferably 0.2% by weight or more, and even more preferably 0.5% by weight or more, Preferably it is 2.0 weight% or less, More preferably, it is 1.5 weight% or less, More preferably, it is 1.0 weight% or less.
- the ratio of the crosslinkable monomer unit in the polycarboxylic acid (A) equal to or more than the lower limit, it is possible to prevent the polycarboxylic acid (A) from dissolving in the battery and to provide a secondary film provided with a porous film.
- the battery can achieve high rate characteristics and high high temperature cycling characteristics.
- polycarboxylic acid (A) contains a reactive surfactant unit.
- the reactive surfactant unit represents a structural unit having a structure obtained by polymerizing a reactive surfactant monomer.
- the reactive surfactant monomer is a monomer having a polymerizable group that can be copolymerized with other monomers and having a surfactant group (that is, a hydrophilic group and a hydrophobic group). Represents a mer.
- the reactive surfactant unit obtained by polymerization of the reactive surfactant monomer constitutes a part of the molecule of the polycarboxylic acid (A) and can function as a surfactant.
- the reactive surfactant monomer has a polymerizable unsaturated group, and this polymerizable unsaturated group also acts as a hydrophobic group after polymerization.
- the polymerizable unsaturated group include a vinyl group, an allyl group, a vinylidene group, a propenyl group, an isopropenyl group, and an isobutylidene group.
- One kind of the polymerizable unsaturated group possessed by one molecule of the polycarboxylic acid (A) may be one kind or two or more kinds.
- the reactive surfactant monomer usually has a hydrophilic group as a portion that exhibits hydrophilicity.
- Reactive surfactant monomers are classified into anionic, cationic and nonionic surfactants depending on the type of hydrophilic group.
- Examples of the anionic hydrophilic group include —SO 3 M, —COOM, and —PO (OM) 2 .
- M represents a hydrogen atom or a cation.
- Examples of cations include alkali metal ions such as lithium, sodium and potassium; alkaline earth metal ions such as calcium and magnesium; ammonium ions; ammonium ions of alkylamines such as monomethylamine, dimethylamine, monoethylamine and triethylamine; and And ammonium ions of alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine.
- Examples of cationic hydrophilic groups include primary amine salts such as —NH 2 HX, secondary amine salts such as —NHCH 3 HX, tertiary amine salts such as —N (CH 3 ) 2 HX, And quaternary amine salts such as —N + (CH 3 ) 3 X — .
- X represents a halogen group.
- An example of a nonionic hydrophilic group is —OH.
- Suitable reactive surfactants include compounds represented by the following formula (II).
- R represents a divalent linking group. Examples of R include —Si—O— group, methylene group and phenylene group.
- R 3 represents a hydrophilic group. An example of R 3 includes —SO 3 NH 4 .
- n represents an integer of 1 to 100.
- a suitable reactive surfactant has a structural unit having a structure formed by polymerizing ethylene oxide and a structural unit having a structure formed by polymerizing butylene oxide.
- Examples thereof include compounds having an alkenyl group having a terminal double bond and —SO 3 NH 4 (for example, trade names “Latemul PD-104” and “Latemul PD-105”, manufactured by Kao Corporation).
- the reactive surfactant and the reactive surfactant unit one type may be used alone, or two or more types may be used in combination at any ratio.
- the content ratio of the reactive surfactant unit in the polycarboxylic acid (A) is usually 0.1% by weight or more, preferably 0.2% by weight or more, more preferably 0.5% by weight or more, and usually 15% by weight. % Or less, preferably 10% by weight or less, more preferably 5% by weight or less.
- the polycarboxylic acid (A) may contain a structural unit other than the units described above as long as the effects of the present invention are not significantly impaired.
- a structural unit may be a structural unit formed by polymerizing a monomer copolymerizable with the above-described monomer. Moreover, these may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.
- the polycarboxylic acid (A) can contain a fluorine-containing (meth) acrylic acid ester monomer unit.
- the proportion of the fluorine-containing (meth) acrylic acid ester monomer unit in the polycarboxylic acid (A) is less than 1% by weight. Is preferred.
- polycarboxylic acid (A) physical properties, etc.
- polycarboxylic acid has a carboxylic acid group, it tends to exhibit high water solubility in an aqueous solution having a high pH and low water solubility in an aqueous solution having a low pH.
- the polycarboxylic acid (A) of the present invention is water-insoluble at pH 6.5 or lower, and water-soluble at pH 8 or higher.
- the minimum of the range of pH which shows water-insoluble property is not specifically limited, For example, it can be 1.0 or more.
- the upper limit of the pH range showing water solubility is not particularly limited, but may be, for example, 12.0 or less.
- the haze of the aqueous solution of polycarboxylic acid (A) having a pH of 6.5 is preferably 70% or more, and more preferably 80% or more.
- the polycarboxylic acid (A) exhibiting such a high haze that is, a high water-insoluble property at a pH of 6.5 or less, it is difficult to agglomerate when preparing the binder composition. It becomes easy.
- good preparation can be performed while avoiding aggregation.
- the upper limit of the haze of the aqueous solution at pH 6.5 is not particularly limited, but can be, for example, 100% or less.
- the haze of an aqueous solution of the aforementioned polycarboxylic acid (A) having a pH of 8.0 is preferably less than 50%, more preferably less than 40%.
- the polycarboxylic acid (A) exhibiting such low haze that is, high water solubility at pH 8.0, sufficient viscosity is expressed in the slurry for the porous film, and the occurrence of defective coating is reduced. Can achieve a high rate characteristic and a high temperature cycle characteristic.
- the minimum of the haze of aqueous solution of pH 8.0 is not specifically limited, For example, it may be 0% or more.
- polycarboxylic acid (A) having both the properties in an aqueous solution at pH 6.5 and the properties in an aqueous solution at pH 8.0 high storage stability of the binder composition and an appropriate viscosity at the time of use. And you can enjoy both benefits.
- the polycarboxylic acid (A) having such properties can be obtained by appropriately adjusting the ratio of the carboxylic acid group-containing monomer unit, the ratio and type of the other monomer unit, and the like.
- the weight average molecular weight of the polycarboxylic acid (A) is preferably 20,000 or more, more preferably 50,000 or more, particularly preferably 100,000 or more, preferably 500,000 or less, more preferably 250,000. It is as follows. By setting the weight average molecular weight of the polycarboxylic acid (A) to be equal to or higher than the lower limit of the above range, the strength of the polycarboxylic acid (A) can be increased and a stable porous film can be formed. In addition, the high temperature storage characteristics of the secondary battery can be improved. Moreover, since polycarboxylic acid (A) can be made soft by setting it as below the upper limit of the said range, the improvement of the adhesiveness to the base material of the porous film of this invention etc.
- the weight average molecular weight of the polycarboxylic acid (A) is a polyethylene oxide using a solution obtained by dissolving 0.85 g / ml sodium nitrate in a 10% by volume aqueous solution of acetonitrile by GPC (gel permeation chromatography). It can be obtained as a conversion value.
- the glass transition temperature of the polycarboxylic acid (A) is preferably ⁇ 50 ° C. or higher, more preferably ⁇ 30 ° C. or higher, even more preferably ⁇ 10 ° C. or higher, while preferably lower than 30 ° C., more preferably 25 ° C. Hereinafter, it is 20 degrees C or less still more preferably.
- the glass transition temperature of the polycarboxylic acid (A) is equal to or higher than the lower limit, the polycarboxylic acid (A) can be easily solubilized, and a sufficient viscosity can be expressed in the slurry for the porous film, resulting in poor coating.
- the secondary battery provided with the porous film can achieve high high temperature cycle characteristics.
- the glass transition temperature of the polycarboxylic acid (A) is not more than the above upper limit, flexibility can be imparted to the porous film, and the adhesion strength between the porous film and the substrate can be increased.
- Polycarboxylic acid (A) production method
- the monomer composition containing the monomer mentioned above can superpose
- the ratio of each monomer in the monomer composition is usually the same as the ratio of the structural units in the polycarboxylic acid (A).
- aqueous solvent examples include water; ketones such as diacetone alcohol and ⁇ -butyrolactone; alcohols such as ethyl alcohol, isopropyl alcohol, and normal propyl alcohol; propylene glycol monomethyl ether, methyl cellosolve, ethyl cellosolve, and ethylene glycol tertiary.
- Glycol ethers such as butyl ether, butyl cellosolve, 3-methoxy-3-methyl-1-butanol, ethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, dipropylene glycol monomethyl ether; 1,3-dioxolane, 1 , 4-dioxolane, ethers such as tetrahydrofuran; and the like.
- water is particularly preferable because it is not flammable. Further, water may be used as the main solvent, and an aqueous solvent other than the water described above may be mixed and used.
- the polymerization method is not particularly limited, and any method such as a solution polymerization method, a suspension polymerization method, a bulk polymerization method, and an emulsion polymerization method may be used.
- a solution polymerization method any method such as ionic polymerization, radical polymerization, and living radical polymerization may be used.
- an aqueous dispersion in which polycarboxylic acid (A) is usually dispersed in an aqueous solvent is obtained.
- the polycarboxylic acid (A) may be taken out from the aqueous dispersion thus obtained.
- a porous membrane binder is produced using the polycarboxylic acid (A) in a state of being dispersed in an aqueous solvent. It can be used to produce a slurry for a porous membrane and a porous membrane.
- the aqueous dispersion of the polycarboxylic acid (A) obtained as a result of the polymerization reaction is usually acidic, it can be adjusted to increase the pH before use in the next step, if necessary.
- the pH of the aqueous dispersion of polycarboxylic acid (A) is preferably 3.0 or higher, more preferably 3.2 or higher, even more preferably 3.5 or higher, while preferably 6 .5 or less.
- the pH of the aqueous dispersion of the polycarboxylic acid (A) is too low, the polycarboxylic acid (A) tends to aggregate when mixed with other materials and the pH suddenly rises.
- An example of a method for increasing the pH includes a method of adding an alkaline aqueous solution.
- basic components constituting the aqueous alkaline solution include ammonia (ammonium hydroxide); hydroxides of alkali metals such as lithium hydroxide, sodium hydroxide and potassium hydroxide; and calcium hydroxide and magnesium hydroxide.
- alkaline earth metal hydroxides included in the said alkaline aqueous solution.
- the said alkaline aqueous solution may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- the binder composition of the present invention may contain a particulate polymer in addition to the polycarboxylic acid (A).
- the binder composition and the slurry for the porous membrane contain the particulate polymer, the following advantages are usually obtained. That is, the binding property of the porous membrane is improved, and the strength against mechanical force applied to the separator or electrode provided with the porous membrane for a secondary battery of the present invention at the time of handling such as winding and transportation can be improved. . Further, since the shape of the particulate polymer is particulate, the particulate polymer can be bound to the non-conductive particles by a point instead of a surface. For this reason, since the hole in a porous film can be enlarged, the internal resistance of a secondary battery can be made small.
- the particulate polymer is insoluble in water, and at least does not dissolve in the binder composition and the slurry for the porous film, and may exist in a dispersed state in a particle shape.
- the particulate polymer can exist while maintaining a part or all of the particle shape.
- Such a particulate polymer can be obtained by appropriately adjusting the proportion of the monomer units as constituent elements.
- the particulate coalescence may contain (meth) acrylic acid ester monomer units.
- the (meth) acrylic acid ester monomer unit is a structural unit having a structure formed by polymerizing a (meth) acrylic acid ester monomer. Since the (meth) acrylic acid ester monomer unit has high strength, the molecules of the particulate polymer can be stabilized.
- Examples of (meth) acrylic acid ester monomers include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, Acrylic acid alkyl esters such as 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, lauryl acrylate, n-tetradecyl acrylate, stearyl acrylate; and methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t -Butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl
- the proportion of the (meth) acrylic acid ester monomer unit in the particulate polymer is preferably 50% by weight or more, more preferably 55% by weight or more, particularly preferably 58% by weight or more, and preferably 98% by weight or less. More preferably, it is 97% by weight or less, particularly preferably 96% by weight or less.
- the particulate polymer may contain a crosslinkable monomer unit used in the polycarboxylic acid (A).
- a crosslinkable monomer unit used in the polycarboxylic acid (A) it is preferable to include a monomer unit containing an N-methylolamide group.
- the monomer unit containing an N-methylolamide group include N-methylol (meth) acrylamide.
- primary amine acrylamide such as (meth) acrylamide in combination.
- the ratio of the acrylamide monomer unit of the primary amine is preferably 50% by mass or more and 200% by mass or less with respect to the ratio of the acrylamide monomer unit having an N-methylol group. By setting it as the said range, it will suppress that a particulate polymer elutes to electrolyte solution, and a favorable battery characteristic comes to be acquired.
- acrylamide of primary amine is included in the crosslinkable monomer unit.
- the proportion of the crosslinkable monomer unit in the particulate polymer is preferably 0.5% by weight or more, more preferably 1.0% by weight or more, while preferably 5% by weight or less, more preferably 4.5%. % By weight or less, still more preferably 4.0% by weight or less.
- the particulate polymer can contain an acid group-containing monomer unit.
- the acid group-containing monomer unit in the particulate polymer refers to a structural unit having a structure formed by polymerizing an acid group-containing monomer. Moreover, an acid group containing monomer shows the monomer containing an acid group. Therefore, the particulate polymer having an acid group-containing monomer unit contains an acid group.
- Examples of acid groups that can be included in the particulate polymer include —COOH group (carboxylic acid group); —SO 3 H group (sulfonic acid group); —PO 3 H 2 group and —PO (OH) (OR) group.
- Phosphonic acid groups such as (R represents a hydrocarbon group); and combinations thereof.
- examples of the acid group-containing monomer include monomers having these acid groups.
- a monomer capable of generating the acid group by hydrolysis is also exemplified as the acid group-containing monomer.
- Specific examples of such acid group-containing monomers include acid anhydrides that can generate carboxylic acid groups by hydrolysis.
- Examples of the monomer having a carboxylic acid group include monocarboxylic acid, dicarboxylic acid, dicarboxylic acid anhydride, and derivatives thereof.
- Examples of monocarboxylic acids include acrylic acid, methacrylic acid, crotonic acid, 2-ethylacrylic acid, and isocrotonic acid.
- Examples of dicarboxylic acids include maleic acid, fumaric acid, itaconic acid, and methylmaleic acid.
- Examples of acid anhydrides of dicarboxylic acids include maleic anhydride, acrylic anhydride, methyl maleic anhydride, and dimethyl maleic anhydride. Among these, monocarboxylic acid is preferable, and acrylic acid and methacrylic acid are more preferable.
- salt of the monomer mentioned above may be used as an acid group containing monomer.
- examples of such salts include sodium salts of styrene sulfonic acid such as p-styrene sulfonic acid.
- an acid group containing monomer and an acid group containing monomer unit may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- the acid group may be introduced by polymerization of the acid group-containing monomer as described above, but after polymerizing the particulate polymer having no acid group, a part of the functional group in the particulate polymer. Or you may introduce
- the repeating unit in the particulate polymer having an acid group thus introduced is also included in the acid group-containing monomer unit.
- the ratio of the acid group-containing monomer unit in the particulate polymer is preferably 0.1% by weight or more, more preferably 0.2% by weight or more, particularly preferably 0.5% by weight or more, preferably 50%. % By weight or less, more preferably 20% by weight or less, particularly preferably 10% by weight or less.
- the particulate polymer can contain an arbitrary structural unit in addition to the structural units described above.
- arbitrary structural units that can be included in the particulate polymer include structural units having a structure formed by polymerizing the following monomers. That is, aliphatic conjugated diene monomers such as 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene; styrene , Aromatic vinyl monomers such as chlorostyrene, vinyl toluene, t-butyl styrene, vinyl benzoic acid, methyl vinyl benzoate, vinyl naphthalene, chloromethyl styrene, hydroxymethyl styrene, ⁇ -methyl styrene, divinylbenzene; acrylonitrile, ⁇ , ⁇ -unsaturated nitrile compound monomers such as methacrylonitrile, ⁇
- N A structural unit having a structure formed by polymerizing one or more of a heterocyclic compound containing a vinyl compound such as vinylpyrrolidone, vinylpyridine and vinylimidazole; Moreover, these may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.
- particulate polymer may be used alone, or two or more kinds of particulate polymers may be used in combination at any ratio.
- the weight average molecular weight of the particulate polymer is preferably 10,000 or more, more preferably 20,000 or more, preferably 1,000,000 or less, more preferably 500,000 or less.
- the weight average molecular weight of the polymer constituting the particulate polymer can be determined by gel permeation chromatography (GPC) as a value in terms of polystyrene using tetrahydrofuran as a developing solvent.
- the glass transition temperature of the particulate polymer is preferably ⁇ 75 ° C. or higher, more preferably ⁇ 55 ° C. or higher, particularly preferably ⁇ 45 ° C. or higher, preferably 40 ° C. or lower, more preferably 30 ° C. or lower, and even more. Preferably it is 20 degrees C or less, Most preferably, it is 15 degrees C or less.
- the glass transition temperature of the particulate polymer can be adjusted, for example, by combining various monomers.
- the volume average particle diameter D50 of the particulate polymer is preferably 0.01 ⁇ m or more, more preferably 0.05 ⁇ m or more, even more preferably 0.1 ⁇ m or more, while preferably 1.0 ⁇ m or less, more preferably 0. 0.8 ⁇ m or less, still more preferably 0.5 ⁇ m or less.
- the ratio of the particulate polymer and the polycarboxylic acid (A) in the porous membrane binder composition is the same as that in the resulting porous membrane slurry. It can set suitably so that the ratio of a polymer and polycarboxylic acid (A) may become a desired range.
- the particulate shape in the binder composition for the porous membrane is preferably set to the same ratio as the preferable ratio between the particulate polymer and the polycarboxylic acid (A) in the obtained slurry for a porous membrane.
- Polymer: Polycarboxylic acid (A) 99: 1 to 80:20.
- the ratio of the polycarboxylic acid (A) to the particulate polymer is equal to or higher than the lower limit, thereby allowing the slurry for the porous membrane to exhibit a sufficient viscosity, reducing the occurrence of coating defects, and high. High temperature cycle characteristics can be achieved.
- the ratio of the polycarboxylic acid (A) to the particulate polymer is not more than the above upper limit, it is possible to prevent the viscosity from becoming too high and achieve coating with less coating unevenness. And high temperature cycling characteristics can be achieved. Therefore, when the ratio of the particulate polymer and the polycarboxylic acid (A) is within this range in the porous membrane binder composition, a preferred porous membrane slurry composition can be easily prepared.
- the particulate polymer can be produced, for example, by polymerizing a monomer composition containing the above-described monomer in an aqueous solvent.
- the content ratio of each monomer in the monomer composition in the polymerization reaction is usually the same as the content ratio of the repeating unit in the desired particulate polymer.
- a solvent in which the particulate polymer can be dispersed in a particle state can be selected.
- An aqueous solvent having a boiling point at normal pressure of preferably 80 to 350 ° C., more preferably 100 to 300 ° C. can be selected.
- aqueous solvents examples include water; ketones such as diacetone alcohol and ⁇ -butyrolactone; alcohols such as ethyl alcohol, isopropyl alcohol, and normal propyl alcohol; propylene glycol monomethyl ether, methyl cellosolve, ethyl cellosolve, and ethylene glycol tertiary.
- Glycol ethers such as butyl ether, butyl cellosolve, 3-methoxy-3-methyl-1-butanol, ethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, dipropylene glycol monomethyl ether; 1,3-dioxolane, 1 , 4-dioxolane, ethers such as tetrahydrofuran; and the like.
- water is particularly preferred from the viewpoint that it is not flammable and a dispersion of particulate polymer particles can be easily obtained.
- water may be used as the main solvent, and an aqueous solvent other than the above water may be mixed and used within a range in which the dispersed state of the particulate polymer particles can be ensured.
- the polymerization method is not particularly limited, and any method such as a solution polymerization method, a suspension polymerization method, a bulk polymerization method, and an emulsion polymerization method can be used.
- the reaction mode of the polymerization may be any of ionic polymerization, radical polymerization, living radical polymerization, and the like. It is easy to obtain a high molecular weight product, and since the polymer is obtained in a state of being dispersed in water as it is, no redispersion treatment is required, and it can be used for the production of the binder composition of the present invention. From the viewpoint of efficiency, the emulsion polymerization method is particularly preferable. Emulsion polymerization can be performed according to a conventional method.
- additives can be used as additives such as emulsifiers, dispersants, polymerization initiators and polymerization aids used in the polymerization.
- the amount of these additives used may also be a commonly used amount.
- the polymerization conditions can be appropriately adjusted according to the polymerization method and the type of polymerization initiator.
- the binder composition of the present invention contains water. Water functions as a medium or solvent or dispersion medium in the binder composition. Usually, in the binder composition, the non-conductive particles and the particulate polymer are dispersed in water. On the other hand, the polycarboxylic acid is dissolved or dispersed in water depending on the pH of the binder composition.
- a medium other than water may be used in combination with water.
- media that can be used in combination with water include cycloaliphatic hydrocarbon compounds such as cyclopentane and cyclohexane; aromatic hydrocarbon compounds such as toluene and xylene; ketone compounds such as ethyl methyl ketone and cyclohexanone; ethyl acetate and acetic acid Ester compounds such as butyl, ⁇ -butyrolactone, ⁇ -caprolactone; nitrile compounds such as acetonitrile and propionitrile; ether compounds such as tetrahydrofuran and ethylene glycol diethyl ether: methanol, ethanol, isopropanol, ethylene glycol, ethylene glycol monomethyl ether, etc.
- Alcohol compounds such as N-methylpyrrolidone (NMP) and N, N-dimethylformamide; and the like. One of these may be used alone, or two or more of these may be used in combination at any ratio.
- the amount of medium other than water is preferably 5 parts by weight or less with respect to 100 parts by weight of water.
- the amount of the solvent in the binder composition is preferably set so that the solid content concentration of the binder composition falls within a desired range.
- the solid content concentration of the specific binder composition is preferably 10% by weight or more, more preferably 15% by weight or more, still more preferably 20% by weight or more, preferably 80% by weight or less, more preferably 75% by weight. % Or less, still more preferably 70% by weight or less, particularly preferably 65% by weight or less.
- the solid content of the composition means a substance remaining after the composition is dried.
- the solid content concentration By setting the solid content concentration to be equal to or higher than the lower limit, it is possible to easily produce a slurry for a porous film having a suitable concentration, and thus easily remove water during the production of the porous film using the slurry. The amount of water in the porous film can be reduced. By setting the solid content concentration to the upper limit or less, a slurry for a porous film suitable for coating can be easily obtained.
- the binder composition of the present invention may further contain acidic and / or basic components for adjusting the pH.
- acidic and basic components include hydrogen chloride; ammonia (ammonium hydroxide); alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide; and calcium hydroxide and magnesium hydroxide. And alkaline earth metal hydroxides.
- the binder composition for porous membranes of the present invention has a pH of 6.5 or less.
- the lower limit of the pH is preferably 5.0 or more, more preferably 5.2 or more, and even more preferably 5.5 or more.
- the polycarboxylic acid (A) can be kept in a water-insoluble state, can suppress aggregation during storage, and has a high stability. Can be obtained.
- the pH of the porous membrane binder composition can be adjusted by adding an aqueous solution containing an acidic or basic component.
- the method for preparing the binder composition for a porous membrane of the present invention is not particularly limited.
- a monomer that becomes a material for the polycarboxylic acid (A) in an aqueous solvent by a method such as the production method described above.
- the porous membrane of the present invention by preparing an aqueous dispersion of the polycarboxylic acid (A), and adjusting the aqueous dispersion as it is, or if necessary, to the preferred range described above. It may be a binder composition.
- the slurry for a secondary battery porous membrane of the present invention contains non-conductive particles, polycarboxylic acid (A) and water.
- Non-conductive particles are components filled in the porous film, and the gaps between the non-conductive particles can form pores of the porous film. Since the non-conductive particles have non-conductivity, the porous film can be made insulative, and therefore a short circuit in the secondary battery can be prevented. In general, non-conductive particles have high rigidity, which can increase the mechanical strength of the porous membrane. For this reason, even if stress that causes shrinkage occurs in the base material such as the separator base material due to heat, the porous film can resist the stress, so it is possible to prevent the occurrence of a short circuit due to the shrinkage of the base material. It is. As the non-conductive particles, inorganic particles or organic particles may be used.
- the inorganic particles are usually excellent in dispersion stability in water, hardly settled in the slurry for the porous membrane, and can maintain a uniform slurry state for a long time.
- the heat resistance of the porous film can usually be increased.
- an electrochemically stable material is preferable.
- inorganic materials for non-conductive particles include aluminum oxide (alumina), aluminum oxide hydrate (boehmite (AlOOH), gibbsite (Al (OH) 3 ), bakelite, oxidation.
- Oxide particles such as iron, silicon oxide, magnesium oxide (magnesia), magnesium hydroxide, calcium oxide, titanium oxide (titania), BaTiO 3 , ZrO, alumina-silica composite oxide; aluminum nitride, silicon nitride, boron nitride, etc.
- Nitride particles covalently-bonded crystal particles such as silicon and diamond; sparingly soluble ionic crystal particles such as barium sulfate, calcium fluoride and barium fluoride; clay fine particles such as silica, talc and montmorillonite;
- alumina, boehmite, and barium sulfate are preferable from the viewpoint of low water absorption and excellent heat resistance (for example, resistance to high temperature of 180 ° C. or higher).
- Polymer particles are usually used as the organic particles.
- the organic particles can control the affinity for water by adjusting the type and amount of the functional group on the surface of the organic particles, and thus can control the amount of water contained in the porous film.
- Organic particles are excellent in that they usually have little metal ion elution.
- the polymer forming the non-conductive particles include various polymer compounds such as polystyrene, polyethylene, polyimide, melamine resin, phenol resin, and acrylic resin.
- the polymer compound forming the particles may be a homopolymer or a copolymer. In the case of a copolymer, any of a block copolymer, a random copolymer, a graft copolymer, and an alternating copolymer is used. it can. Furthermore, it may be at least partially modified or a crosslinked product. And a mixture of these may be sufficient.
- the cross-linking agent includes a cross-linked product having an aromatic ring such as divinylbenzene, a polyfunctional acrylate cross-linked product such as ethylene glycol dimethacrylate, and a cross-linked product having an epoxy group such as glycidyl acrylate and glycidyl methacrylate.
- an aromatic ring such as divinylbenzene
- a polyfunctional acrylate cross-linked product such as ethylene glycol dimethacrylate
- an epoxy group such as glycidyl acrylate and glycidyl methacrylate.
- the organic particles are usually polymer particles having no glass transition temperature or polymer particles having a high glass transition temperature.
- the glass transition temperature is preferably 150 ° C. or higher, more preferably 200 ° C. or higher, particularly preferably 250 ° C. or higher, and usually 500 ° C. or lower.
- the method for producing organic particles as non-conductive particles is not particularly limited, and any method such as a solution polymerization method, a suspension polymerization method, or an emulsion polymerization method may be used.
- the emulsion polymerization method and the suspension polymerization method are preferable because they can be polymerized in water and used as they are as the material for the slurry for the porous membrane.
- the organic particles are generally composed of a polymer that substantially constitutes the organic particles, but may be accompanied by any component such as an additive added during the polymerization.
- Non-conductive particles may be subjected to, for example, element substitution, surface treatment, solid solution, and the like as necessary. Further, the non-conductive particles may include one kind of the above materials alone in one particle, or may contain two or more kinds in combination at an arbitrary ratio. . Further, the non-conductive particles may be used in combination of two or more kinds of particles formed of different materials.
- Examples of the shape of the nonconductive particles include a spherical shape, an elliptical spherical shape, a polygonal shape, a tetrapod (registered trademark) shape, a plate shape, and a scale shape.
- the volume average particle diameter of the non-conductive particles is preferably 0.1 ⁇ m or more, more preferably 0.2 ⁇ m or more, preferably 5 ⁇ m or less, more preferably 1 ⁇ m or less.
- the volume average particle diameter of the non-conductive particles represents a particle diameter at which the cumulative volume calculated from the small diameter side becomes 50% in the particle diameter distribution measured by the laser diffraction method.
- the BET specific surface area of the non-conductive particles is, for example, preferably 0.9 m 2 / g or more, more preferably 1.5 m 2 / g or more. Further, from the viewpoint of suppressing aggregation of non-conductive particles and optimizing the fluidity of the slurry for the porous membrane, the BET specific surface area is preferably not too large, for example, 150 m 2 / g or less.
- the ratio of the non-conductive particles in the slurry for the secondary battery porous membrane of the present invention is within a range where the effect of the polycarboxylic acid (A) is satisfactorily expressed relative to the polycarboxylic acid (A). It can be set as appropriate. Specifically, the ratio of polycarboxylic acid (A) to 100 parts by weight of non-conductive particles is preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more, while preferably 10 parts by weight. Below, more preferably 5 parts by weight or less.
- the slurry for a porous membrane of the present invention contains water. Further, as a medium, a medium other than water may be used in combination with water. Examples of the medium that can be used in combination with water and examples of the ratio of these to water include the same medium as in the binder composition.
- the amount of water in the porous membrane slurry is not particularly limited, and can be appropriately adjusted so that the physical properties of the porous membrane slurry are within a preferable range.
- the slurry for a porous membrane of the present invention can contain any component in addition to the components described above.
- optional components those which do not exert an excessively unfavorable influence on the battery reaction can be used.
- an arbitrary component one type may be used alone, or two or more types may be used in combination at an arbitrary ratio.
- the slurry for a porous membrane of the present invention can contain a water-soluble thickener other than the polycarboxylic acid (A).
- a water-soluble thickener such as carboxymethylcellulose salt can increase the viscosity of the slurry for porous membrane, the applicability of the slurry for porous membrane can be improved.
- carboxymethyl cellulose salt can usually increase the dispersion stability of the non-conductive particles in the slurry for the porous membrane, and can improve the binding property between the porous membrane and the separator substrate or the electrode plate.
- carboxymethyl cellulose salt include a sodium salt and an ammonium salt.
- carboxymethylcellulose salt may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- the amount of the carboxymethyl cellulose salt is preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more, preferably 10 parts by weight or less, more preferably 7 parts by weight with respect to 100 parts by weight of the non-conductive particles. It is at most 5 parts by weight, particularly preferably at most 5 parts by weight.
- the amount of the carboxymethyl cellulose salt is also contained in the porous membrane.
- strength of a porous film can be made high by making the quantity of a carboxymethylcellulose salt more than the lower limit of the said range.
- flexibility of a porous film can be made favorable by setting it as below an upper limit.
- the slurry for a porous membrane of the present invention has, for example, an isothiazoline compound, a pyrithione compound, a dispersant, a leveling agent, an antioxidant, a thickener, an antifoaming agent, a wetting agent, and an electrolyte decomposition inhibiting function.
- the electrolyte solution additive etc. which it has may be included.
- the porous membrane slurry of the present invention may further contain an acidic component and / or a basic component for adjusting the pH.
- an acidic component and the basic component are the same as those exemplified as the components of the binder composition.
- the pH of the slurry for a porous membrane of the present invention is over 7.0, preferably 7.5 or more, more preferably 8.0 or more, and even more preferably 8.5 or more.
- the polycarboxylic acid (A) is made into a water-soluble state, and due to its thickening effect, sufficient viscosity is expressed in the slurry for the porous film, thereby reducing the occurrence of poor coating.
- High temperature cycle characteristics can be achieved.
- the upper limit of pH is not specifically limited, For example, it can be set to 12.0.
- the pH of the slurry for the porous membrane can be adjusted by adjusting the content of the polycarboxylic acid and other components, and if necessary, adding an acidic or basic component that adjusts the pH during the production of the slurry for the porous membrane. Can be adjusted.
- the slurry for porous film of the present invention can be prepared to have a viscosity suitable for coating.
- the viscosity of the slurry for a porous membrane of the present invention is preferably 20 mPa ⁇ s or more, more preferably 50 mPa ⁇ s or more, still more preferably 70 mPa ⁇ s or more, while preferably 250 mPa ⁇ s or less, more preferably 150 mPa ⁇ s. s or less, more preferably 100 mPa ⁇ s or less.
- the viscosity of the slurry for the porous film is a value measured using a B-type viscometer at a temperature of 25 ° C. and a rotation speed of 60 rpm.
- the viscosity of the slurry for the porous membrane can be adjusted by adjusting the molecular weight of the polycarboxylic acid and the contents of the polycarboxylic acid, water, acidic component, and basic component.
- the slurry for the porous membrane of the present invention can be produced by any production method, but as a preferred example of the method for producing the slurry for the porous membrane of the present invention, a method of mixing the binder composition of the present invention and other components. Is mentioned.
- a method of mixing the binder composition of the present invention and other components it is preferable to supply all of the polycarboxylic acid (A) and the particulate polymer by adding a binder composition for a porous film containing them.
- the above components, particularly non-conductive particles can be dispersed in the slurry for the porous membrane using a disperser, if necessary.
- the disperser it is preferable to use a medialess disperser because the particle size of the non-conductive particles is hardly reduced undesirably.
- the pH can be adjusted as necessary before or after such mixing.
- the pH can be adjusted by appropriately adding an acid or a base.
- the binder composition of the present invention has a pH in a specific range and has the specific polycarboxylic acid (A), so that the binder composition can be used in a stable state and for easy use. In the state, the polycarboxylic acid (A) can be retained. By using this, it is mixed with the other components that make up the slurry for porous membranes, and if necessary, the pH is adjusted to a specific range to produce a slurry for porous membranes. Both stability and moderate viscosity at the time of use can be enjoyed.
- porous membrane for a secondary battery of the present invention forms a layer of the slurry for a secondary battery porous membrane of the present invention and is dried.
- the porous membrane slurry layer can be obtained by applying a porous membrane slurry on a substrate.
- a base material is a member used as the object which forms the film
- membrane of the slurry for porous films is formed in the surface of a peeling film, A solvent is removed from the film
- the constituent elements of the battery are used as the base material. Examples of such battery components include separator substrates and electrode plates.
- the coating method examples include a doctor blade method, a dip method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, and a brush coating method.
- the dip method and the gravure method are preferable in that a uniform porous film can be obtained. Since the slurry for porous film of the present invention contains a specific composition and physical properties, its application is easy, a high-quality layer can be easily obtained, and the amount of water remaining in the porous film is reduced. Can be reduced.
- Specific examples of the method for drying the porous membrane slurry layer include drying with warm air, hot air, low-humidity air, etc .; vacuum drying; drying by irradiation with infrared rays, far infrared rays, and electron beams. It is done.
- the temperature during drying is preferably 40 ° C. or higher, more preferably 45 ° C. or higher, particularly preferably 50 ° C. or higher, preferably 90 ° C. or lower, more preferably 80 ° C. or lower.
- the drying time is preferably 5 seconds or more, more preferably 10 seconds or more, particularly preferably 15 seconds or more, preferably 3 minutes or less, more preferably 2 minutes or less.
- the porous film may be subjected to pressure treatment by a pressing method such as a mold press and a roll press.
- a pressing method such as a mold press and a roll press.
- the pressure treatment By performing the pressure treatment, the binding property between the substrate and the porous film can be improved.
- it is preferable to appropriately control the pressure and the pressurization time so as not to become excessively large.
- the thickness of the porous membrane of the present invention is preferably 0.1 ⁇ m or more, more preferably 0.2 ⁇ m or more, particularly preferably 0.3 ⁇ m or more, preferably 20 ⁇ m or less, more preferably 15 ⁇ m or less, particularly preferably 10 ⁇ m or less. It is.
- the thickness of the porous film By setting the thickness of the porous film to be equal to or more than the lower limit of the above range, the heat resistance of the porous film can be increased. Moreover, the fall of the ionic conductivity by a porous film can be suppressed by setting it as an upper limit or less.
- a separator for a secondary battery including the separator base material and the porous membrane of the present invention is obtained.
- the porous membrane of the present invention may be provided on only one side of the separator substrate, or may be provided on both sides.
- the separator provided with the porous membrane of the present invention is used as the separator, the residual moisture content in the porous membrane is small, the thermal shrinkage of the porous membrane is small, and the adhesion strength between the porous membrane and the substrate is high. Therefore, the high temperature cycle characteristics of the secondary battery can be improved.
- the separator substrate for example, a porous substrate having fine pores can be used.
- a separator base material By using such a separator base material, it is possible to prevent a short circuit without interfering with charge / discharge of the battery in the secondary battery.
- the microporous film or nonwoven fabric containing polyolefin resin such as polyethylene resin and a polypropylene resin, an aromatic polyamide resin, etc. are mentioned.
- the thickness of the separator substrate is preferably 0.5 ⁇ m or more, more preferably 1 ⁇ m or more, preferably 40 ⁇ m or less, more preferably 30 ⁇ m or less. Within this range, the resistance due to the separator substrate in the secondary battery is reduced, and the workability during battery production is excellent.
- Electrode plate refers to a member other than the porous film among the electrodes including the porous film.
- the electrode plate usually includes a current collector and an electrode active material layer.
- the electrode for a secondary battery including the electrode plate and the porous film of the present invention usually includes a current collector, an electrode active material layer, and the porous film of the present invention in this order.
- a layer configuration of current collector / electrode active material layer / porous film can be taken.
- a layer configuration of porous film / electrode active material layer / current collector / electrode active material layer / porous film can be taken.
- the electrode including the porous film of the present invention when used as an electrode, the residual moisture content in the porous film is small, the thermal contraction of the porous film is small, and the adhesion strength between the porous film and the substrate is high. Therefore, the high temperature cycle characteristics of the secondary battery can be improved.
- an electrically conductive and electrochemically durable material can be used as the current collector of the electrode plate.
- a metal material is used as the material of the current collector. Examples thereof include iron, copper, aluminum, nickel, stainless steel, titanium, tantalum, gold, platinum and the like.
- the current collector used for the positive electrode is preferably aluminum
- the current collector used for the negative electrode is preferably copper.
- the said material may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- the shape of the current collector is not particularly limited, but a sheet having a thickness of about 0.001 mm to 0.5 mm is preferable.
- Electrode active material layer is a layer provided on the current collector and includes an electrode active material.
- electrode active material There are various types of electrode active materials depending on the types of secondary batteries. Here, electrode active materials for lithium ion secondary batteries will be described in particular. However, the electrode active material is not limited to those listed below.
- the electrode active material of the lithium ion secondary battery a material capable of reversibly inserting or releasing lithium ions by applying a potential in an electrolytic solution can be used.
- the electrode active material an inorganic compound or an organic compound may be used.
- the positive electrode active material is roughly classified into those made of inorganic compounds and those made of organic compounds.
- Examples of the positive electrode active material made of an inorganic compound include transition metal oxides, composite oxides of lithium and transition metals, and transition metal sulfides.
- Examples of the transition metal include Fe, Co, Ni, and Mn.
- the inorganic compound used for the positive electrode active material include LiCoO 2 , LiNiO 2 , LiMnO 2 , LiMn 2 O 4 , LiFePO 4 , LiFeVO 4, and other lithium-containing composite metal oxides; TiS 2 , TiS 3 , non- Transition metal sulfides such as crystalline MoS 2 ; transition metal oxides such as Cu 2 V 2 O 3 , amorphous V 2 O—P 2 O 5 , MoO 3 , V 2 O 5 , V 6 O 13, etc. Can be mentioned.
- examples of the positive electrode active material made of an organic compound include conductive polymers such as polyacetylene and poly-p-phenylene.
- the positive electrode active material which consists of a composite material which combined the inorganic compound and the organic compound.
- a composite material covered with a carbon material may be produced by reducing and firing an iron-based oxide in the presence of a carbon source material, and the composite material may be used as a positive electrode active material.
- Iron-based oxides tend to have poor electrical conductivity, but can be used as a high-performance positive electrode active material by using a composite material as described above.
- you may use as a positive electrode active material what carried out the element substitution of the said compound partially.
- These positive electrode active materials may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- the particle size of the positive electrode active material can be selected in consideration of other constituent requirements of the secondary battery.
- the volume average particle diameter of the positive electrode active material is preferably 0.1 ⁇ m or more, more preferably 1 ⁇ m or more, preferably 50 ⁇ m or less, more preferably 20 ⁇ m or less. It is. When the volume average particle diameter of the positive electrode active material is within this range, a battery having a large charge / discharge capacity can be obtained, and handling of the electrode slurry composition and the electrode is easy.
- the ratio of the positive electrode active material in the electrode active material layer is preferably 90% by weight or more, more preferably 95% by weight or more, and preferably 99.9% by weight or less, more preferably 99% by weight or less.
- the negative electrode active material examples include carbonaceous materials such as amorphous carbon, graphite, natural graphite, artificial graphite, mesocarbon microbeads, and pitch-based carbon fibers; and conductive polymers such as polyacene.
- metals such as silicon, tin, zinc, manganese, iron and nickel, and alloys thereof; oxides of the metals or alloys; sulfates of the metals or alloys; Further, metallic lithium; lithium alloys such as Li—Al, Li—Bi—Cd, and Li—Sn—Cd; lithium transition metal nitride; silicon and the like may be used.
- an electrode active material having a conductive material attached to the surface by a mechanical modification method may be used. These negative electrode active materials may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- the particle size of the negative electrode active material is appropriately selected in consideration of other constituent requirements of the secondary battery.
- the volume average particle diameter of the negative electrode active material is preferably 0.1 ⁇ m or more, more preferably 1 ⁇ m or more, and even more preferably 5 ⁇ m or more. Is 100 ⁇ m or less, more preferably 50 ⁇ m or less, and still more preferably 20 ⁇ m or less.
- the specific surface area of negative electrode active material the output from the viewpoints of improving the density, preferably 2m 2 / g or more, more preferably 3m 2 / g or more, more preferably 5 m 2 / g or more, and preferably 20 m 2 / g or less, more preferably 15 m 2 / g or less, and further preferably 10 m 2 / g or less.
- the specific surface area of the negative electrode active material can be measured by, for example, the BET method.
- the proportion of the negative electrode active material in the electrode active material layer is preferably 85% by weight or more, more preferably 88% by weight or more, and preferably 99% by weight or less, more preferably 97% by weight or less.
- the electrode active material layer preferably contains an electrode binder in addition to the electrode active material.
- an electrode binder in addition to the electrode active material.
- the binding property of the electrode active material layer is improved, and the strength against the mechanical force applied in the process of winding the electrode is increased.
- the electrode active material layer is less likely to be peeled off from the current collector and the porous film, the risk of short-circuiting due to the detached desorbed material is reduced.
- a polymer can be used as the binder for the electrode.
- the polymer that can be used as an electrode binder include polyethylene, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polyacrylic acid derivatives, poly An acrylonitrile derivative or the like may be used.
- the soft polymer particles exemplified below may be used as the particulate polymer.
- a soft polymer for example, (I) Polybutyl acrylate, polybutyl methacrylate, polyhydroxyethyl methacrylate, polyacrylamide, polyacrylonitrile, butyl acrylate / styrene copolymer, butyl acrylate / acrylonitrile copolymer, butyl acrylate / acrylonitrile / glycidyl methacrylate copolymer, etc.
- An acrylic soft polymer which is a homopolymer of acrylic acid or a methacrylic acid derivative or a copolymer thereof with a monomer copolymerizable therewith;
- isobutylene-based soft polymers such as polyisobutylene, isobutylene-isoprene rubber, isobutylene-styrene copolymer;
- These soft polymers may have a cross-linked structure or may have a functional group introduced by modification.
- the polymer may be in the form of particles or non-particulates.
- the binder for electrodes may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- the amount of the binder for the electrode in the electrode active material layer is preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more, particularly preferably 0.5 parts by weight or more with respect to 100 parts by weight of the electrode active material. It is preferably 5 parts by weight or less, more preferably 3 parts by weight or less. When the amount of the electrode binder is within the above range, it is possible to prevent the electrode active material from dropping from the electrode without inhibiting the battery reaction.
- the electrode active material layer may contain any component other than the electrode active material and the electrode binder as long as the effects of the present invention are not significantly impaired. Examples thereof include a conductive material and a reinforcing material. Moreover, arbitrary components may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- Examples of the conductive material include conductive carbon such as acetylene black, ketjen black, carbon black, graphite, vapor-grown carbon fiber, and carbon nanotube; carbon powder such as graphite; fibers and foils of various metals; .
- conductive carbon such as acetylene black, ketjen black, carbon black, graphite, vapor-grown carbon fiber, and carbon nanotube
- carbon powder such as graphite
- fibers and foils of various metals .
- the specific surface area of the conductive material is preferably 50 m 2 / g or more, more preferably 60 m 2 / g or more, particularly preferably 70 m 2 / g or more, preferably 1500 m 2 / g or less, more preferably 1200 m 2 / g. Hereinafter, it is particularly preferably 1000 m 2 / g or less.
- the reinforcing material for example, various inorganic and organic spherical, plate, rod or fiber fillers can be used. By using the reinforcing material, a tough and flexible electrode can be obtained, and excellent long-term cycle characteristics can be obtained.
- the amount of the conductive material and the reinforcing agent used is usually 0 part by weight or more, preferably 1 part by weight or more, preferably 20 parts by weight or less, more preferably 10 parts by weight, with respect to 100 parts by weight of the electrode active material. It is as follows.
- the thickness of the electrode active material layer is preferably 5 ⁇ m or more, more preferably 10 ⁇ m or more, preferably 300 ⁇ m or less, more preferably 250 ⁇ m or less for both the positive electrode and the negative electrode.
- the method for producing the electrode active material layer is not particularly limited.
- the electrode active material layer can be produced by, for example, applying an electrode active material and a solvent, and, if necessary, an electrode slurry composition containing an electrode binder and optional components onto a current collector and drying it.
- the solvent either water or an organic solvent can be used.
- the secondary battery of the present invention includes the porous film of the present invention.
- a secondary battery usually includes a positive electrode, a negative electrode, and an electrolyte, and satisfies the following requirement (A), the requirement (B), or both the requirements (A) and (B).
- At least one of the positive electrode and the negative electrode of the secondary battery of the present invention is an electrode including the electrode plate and the porous film of the present invention.
- the secondary battery of the present invention includes a separator, and the separator includes a separator base material and the porous film of the present invention.
- the porous film of the present invention has a small amount of residual moisture, little heat shrinkage, and can increase the adhesion strength between the porous film and the substrate. Therefore, when the electrode and / or separator provided with the porous film of the present invention is used as a constituent element of a secondary battery, the high-temperature cycle characteristics of the secondary battery can be improved.
- the secondary battery of the present invention includes a separator including the porous film of the present invention as a separator.
- a separator other than the separator including the porous film of the present invention may be provided as a separator.
- the separator since the porous film in the electrode provided with the porous film of the present invention has a function as a separator, the separator may be omitted when the electrode includes the porous film of the present invention.
- the secondary battery of the present invention includes an electrode including the porous film of the present invention as one or both of a positive electrode and a negative electrode.
- the secondary battery of the present invention includes a separator including the porous film of the present invention as a separator, an electrode that does not include the porous film of the present invention may be provided as both a positive electrode and a negative electrode.
- Electrolyte As the electrolytic solution, for example, a solution obtained by dissolving a lithium salt as a supporting electrolyte in a non-aqueous solvent can be used.
- the lithium salt include 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, (C 2 F 5 SO 2 ) NLi, and the like.
- LiPF 6 , LiClO 4 , and CF 3 SO 3 Li that are easily soluble in a solvent and exhibit a high degree of dissociation are preferably used.
- One of these may be used alone, or two or more of these may be used in combination at any ratio.
- the amount of the supporting electrolyte is preferably 1% by weight or more, more preferably 5% by weight or more, preferably 30% by weight or less, more preferably 20% by weight or less, as the concentration in the electrolytic solution.
- a solvent capable of dissolving the supporting electrolyte can be used.
- alkyl carbonate compounds such as dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), butylene carbonate (BC), and ethyl methyl carbonate (EMC).
- Ester compounds such as ⁇ -butyrolactone and methyl formate; ether compounds such as 1,2-dimethoxyethane and tetrahydrofuran; sulfur-containing compounds such as sulfolane and dimethyl sulfoxide;
- dimethyl carbonate, ethylene carbonate, propylene carbonate, diethyl carbonate, and ethyl methyl carbonate are preferred because high ion conductivity is easily obtained and the use temperature range is wide.
- a solvent may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.
- the electrolytic solution may contain an additive as necessary.
- an additive for example, carbonate compounds such as vinylene carbonate (VC) are preferable.
- An additive may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.
- the manufacturing method of the secondary battery of the present invention is not particularly limited.
- the above-described negative electrode and positive electrode may be overlapped via a separator, and this may be wound or folded in accordance with the shape of the battery and placed in the battery container, and the electrolyte may be injected into the battery container and sealed.
- an expanded metal; an overcurrent prevention element such as a fuse or a PTC element; a lead plate or the like may be inserted to prevent an increase in pressure inside the battery or overcharge / discharge.
- the shape of the battery may be any of, for example, a laminate cell type, a coin type, a button type, a sheet type, a cylindrical type, a square type, and a flat type.
- Glass transition temperature of polycarboxylic acid (A) The polycarboxylic acid (A) was dried for 3 days in an environment of 50% humidity and 25 ° C. to obtain a film having a thickness of 1.0 mm. This film was dried with a 60 ° C. vacuum dryer for 10 hours. Then, using the dried film as a sample, DSC6220SII (differential scanning calorimeter, manufactured by Nanotechnology Co., Ltd.) under a measurement temperature of ⁇ 100 ° C. to 180 ° C. and a heating rate of 5 ° C./min according to JIS K 7121. was used to measure the glass transition temperature (° C.).
- DSC6220SII differential scanning calorimeter, manufactured by Nanotechnology Co., Ltd.
- the viscosity of the slurry for porous membrane was measured using a B-type viscometer at 25 ° C. and a rotation speed of 60 rpm.
- PH measurement method A desktop pH meter (F-51 manufactured by HORIBA) was calibrated with pH standard solutions (pH 4, pH 7 and pH 9), and then the pH of the sample was measured.
- Solid content concentration maintenance rate is 95% or more and 100% or less
- Solid content concentration maintenance rate is 90% or more and less than 95%
- Solid content concentration maintenance rate is 85% or more and less than 90%
- Solid content concentration maintenance rate Less than 85%
- Capacity maintenance ratio is 70% or more
- Example 1 (1-1. Preparation of polycarboxylic acid (A)) In a 5 MPa pressure vessel equipped with a stirrer, 100.0 parts of the monomer composition, 150 parts of ion-exchanged water, and 1.0 part of potassium persulfate (polymerization initiator) were added and stirred sufficiently, and then heated to 60 ° C. Then, polymerization was started.
- A polycarboxylic acid
- the monomer composition is 30 parts of methacrylic acid (carboxylic acid group-containing monomer), 56 parts of ethyl acrylate (monomer (U1)), 12.2 parts of butyl acrylate (monomer (U2)), ethylene Containing 0.8 parts of dimethacrylate (crosslinkable monomer) and 1.0 part of polyoxyalkylene alkenyl ether ammonium sulfate (reactive surfactant, trade name “Latemul PD-104” (manufactured by Kao Corporation)) did.
- the reaction is stopped by cooling, and an aqueous sodium hydroxide solution is further added to adjust the pH to 4.0 to obtain an aqueous dispersion containing the polycarboxylic acid (A). It was. About the obtained polycarboxylic acid (A), the water solubility in pH 6.5 and 8.0 was evaluated.
- the reaction was stopped by cooling to obtain a mixture containing a particulate polymer.
- a 5% aqueous sodium hydroxide solution was added to the mixture containing the particulate polymer to adjust the pH to 6.5 to obtain an aqueous dispersion containing the desired particulate polymer.
- (1-3. Production of binder composition for porous membrane) 90 parts of an aqueous dispersion containing the particulate polymer obtained in the step (1-2) (corresponding to a solid content) and 10% of the aqueous dispersion containing the polycarboxylic acid (A) obtained in the step (1-1) Parts (corresponding to solid content) were mixed to obtain a binder composition for porous membrane. About the obtained binder composition for porous films, pH was measured. Moreover, the stability of the binder composition for porous films was evaluated.
- the slurry for porous film obtained in the step (1-4) is dried on a gravure coater on one surface of a single-layer polypropylene separator substrate (manufactured by Celgard, trade name “Celgard 2500”).
- the coating amount was 6 mg / cm 2 and dried. This drying was performed by conveying the separator base material at a rate of 20 m / min in an oven at 100 ° C. over 1 minute. This obtained the separator provided with the separator base material and the porous film formed on the one surface. The adhesion strength of the obtained separator was evaluated.
- the obtained positive electrode slurry composition was applied onto a 20 ⁇ m-thick aluminum foil as a current collector by a comma coater so that the film thickness after drying was about 150 ⁇ m and dried. This drying was performed by transporting the aluminum foil in an oven at 60 ° C. at a speed of 0.5 m / min for 2 minutes. Thereafter, the positive electrode raw material was rolled by a roll press to obtain a positive electrode having a positive electrode active material layer thickness of 95 ⁇ m.
- a 5% aqueous sodium hydroxide solution was added to the mixture containing the negative electrode active material layer binder, and the pH was adjusted to 8. Then, unreacted monomers were removed by heating under reduced pressure. Then, it cooled to 30 degrees C or less, and obtained the water dispersion liquid containing the binder for desired negative electrode active material layers.
- the above-mentioned binder for negative electrode active material layer (SBR) was added in an amount corresponding to a solid content of 1.5 parts and ion-exchanged water, adjusted to a final solid content concentration of 52%, and further mixed for 10 minutes. This was defoamed under reduced pressure to prepare a slurry composition for negative electrode having good fluidity.
- the obtained negative electrode slurry composition was applied on a copper foil having a thickness of 20 ⁇ m, which was a current collector, with a comma coater so that the film thickness after drying was about 150 ⁇ m, and dried.
- This drying was performed by conveying the copper foil in an oven at 60 ° C. at a speed of 0.5 m / min for 2 minutes. Then, the negative electrode original fabric was rolled by a roll press to obtain a negative electrode having a negative electrode active material layer thickness of 100 ⁇ m.
- the positive electrode obtained in the step (1-6) was cut into a 4.6 cm ⁇ 4.6 cm square to obtain a rectangular positive electrode.
- the separator obtained in the step (1-5) was cut into a 5.5 cm ⁇ 5.5 cm square to obtain a rectangular separator.
- the negative electrode obtained in the step (1-7) was cut into a 5 cm ⁇ 5 cm square to obtain a rectangular negative electrode.
- a rectangular positive electrode was placed in the packaging material exterior so that the current collector-side surface was in contact with the aluminum packaging exterior.
- a rectangular separator was disposed so that the surface on the porous membrane side was in contact with the rectangular positive electrode.
- a rectangular negative electrode was placed on the separator so that the surface on the negative electrode active material layer side faces the separator.
- heat sealing at 150 ° C. was performed to close the exterior of the aluminum packaging material, and a lithium ion secondary battery was manufactured. The lithium ion secondary battery was evaluated for high-temperature cycle characteristics.
- Example 2 A lithium ion secondary battery was produced in the same manner as in Example 1 except that the following matters were changed, and measurements and evaluations on the lithium ion secondary battery and its components were performed.
- the monomer composition is composed of 28 parts of methacrylic acid (a carboxylic acid group-containing monomer) and 58 parts of ethyl acrylate (monomer (U1)). Parts, butyl acrylate (monomer (U2)) 12.2 parts, ethylene dimethacrylate (crosslinkable monomer) 0.8 parts, polyoxyalkylene alkenyl ether ammonium sulfate (reactive surfactant) 1.0 part It changed to become.
- Example 3 A lithium ion secondary battery was produced in the same manner as in Example 1 except that the following matters were changed, and measurements and evaluations on the lithium ion secondary battery and its components were performed.
- the monomer composition is 35 parts of methacrylic acid (carboxylic acid group-containing monomer), 45 parts of ethyl acrylate (monomer (U1)).
- Example 4 A lithium ion secondary battery was produced in the same manner as in Example 1 except that the following matters were changed, and measurements and evaluations on the lithium ion secondary battery and its components were performed.
- the monomer composition is composed of 22 parts of methacrylic acid (carboxylic acid group-containing monomer), ethyl acrylate (monomer (U1)) 56 Parts, butyl acrylate (monomer (U2)) 20.2 parts, ethylene dimethacrylate (crosslinkable monomer) 0.8 parts, polyoxyalkylene alkenyl ether ammonium sulfate (reactive surfactant) 1.0 part It changed to become.
- the monomer composition comprises 44 parts of methacrylic acid (carboxylic acid group-containing monomer), 29 ethyl acrylate (monomer (U1)) 29 Parts, butyl acrylate (monomer (U2)) 25.2 parts, ethylene dimethacrylate (crosslinkable monomer) 0.8 parts, polyoxyalkylene alkenyl ether ammonium sulfate (reactive surfactant) 1.0 part It changed to become.
- Example 6 A lithium ion secondary battery was produced in the same manner as in Example 1 except that the following matters were changed, and measurements and evaluations on the lithium ion secondary battery and its components were performed.
- the polycarboxylic acid (A) in the step (1-1) an aqueous dispersion of polycarboxylic acid having a pH of 3.3 was obtained without adjusting the pH after stopping the reaction. This was used as it was as an aqueous dispersion of polycarboxylic acid in the subsequent steps.
- Example 7 A lithium ion secondary battery was produced in the same manner as in Example 1 except that the following matters were changed, and measurements and evaluations on the lithium ion secondary battery and its components were performed.
- an aqueous sodium hydroxide solution was added to adjust the pH to 6.4 instead of 4.0.
- an aqueous sodium hydroxide solution was added to adjust the pH to 6.4 instead of 6.5.
- the monomer composition comprises 30 parts of methacrylic acid (carboxylic acid group-containing monomer), ethyl acrylate (monomer (U1)) 34 Parts, butyl acrylate (monomer (U2)) 34.2 parts, ethylene dimethacrylate (crosslinkable monomer) 0.8 parts, polyoxyalkylene alkenyl ether ammonium sulfate (reactive surfactant) 1.0 part It changed to become.
- Example 9 A lithium ion secondary battery was produced in the same manner as in Example 1 except that the following matters were changed, and measurements and evaluations on the lithium ion secondary battery and its components were performed.
- the monomer composition is composed of 30 parts of methacrylic acid (carboxylic acid group-containing monomer), 59 of ethyl acrylate (monomer (U1)).
- the monomer composition comprises 35 parts of methacrylic acid (carboxylic acid group-containing monomer), ethyl acrylate (monomer (U1)) 51 Parts, butyl acrylate (monomer (U2)) 12.2 parts, ethylene dimethacrylate (crosslinkable monomer) 0.8 parts, polyoxyalkylene alkenyl ether ammonium sulfate (reactive surfactant) 1.0 part It changed to become.
- Example 11 A lithium ion secondary battery was produced in the same manner as in Example 1 except that the following matters were changed, and measurements and evaluations on the lithium ion secondary battery and its components were performed.
- the monomer composition was mixed with 95 parts of butyl acrylate, 2 parts of acrylonitrile, 2 parts of methacrylic acid, 0.5 part of N-methylol acrylamide, and 0. Changed to 5 parts.
- Example 12 A lithium ion secondary battery was produced in the same manner as in Example 1 except that the following matters were changed, and measurements and evaluations on the lithium ion secondary battery and its components were performed.
- the monomer composition was composed of 92.2 parts of butyl acrylate, 2 parts of acrylonitrile, 2 parts of methacrylic acid, 1.9 parts of N-methylol acrylamide, and acrylamide Changed to 1.9 parts.
- Example 13 A lithium ion secondary battery was produced in the same manner as in Example 1 except that the following matters were changed, and measurements and evaluations on the lithium ion secondary battery and its components were performed.
- the proportion of the aqueous dispersion containing the particulate polymer obtained in the step (1-2) is 98 parts (corresponding to the solid content)
- the step The proportion of the aqueous dispersion containing the polycarboxylic acid (A) obtained in (1-1) was 2 parts (corresponding to the solid content).
- Example 14 A lithium ion secondary battery was produced in the same manner as in Example 1 except that the following matters were changed, and measurements and evaluations on the lithium ion secondary battery and its components were performed.
- the proportion of the aqueous dispersion containing the particulate polymer obtained in the step (1-2) is 55 parts (corresponding to the solid content)
- the step The proportion of the aqueous dispersion containing the polycarboxylic acid (A) obtained in (1-1) was 45 parts (corresponding to the solid content).
- Example 15 A lithium ion secondary battery was produced in the same manner as in Example 1 except that the following matters were changed, and measurements and evaluations on the lithium ion secondary battery and its components were performed.
- an aqueous sodium hydroxide solution was added to adjust the pH to 5.5 instead of 6.5.
- Example 16 A lithium ion secondary battery was produced in the same manner as in Example 1 except that the following matters were changed, and measurements and evaluations on the lithium ion secondary battery and its components were performed. Step (1-4) In adjusting the pH in the production of the slurry for the porous membrane, an aqueous sodium hydroxide solution was added to adjust the pH to 7.1 instead of 9.0.
- Example 17 A lithium ion secondary battery was produced in the same manner as in Example 1 except that the following matters were changed, and measurements and evaluations on the lithium ion secondary battery and its components were performed.
- the monomer composition comprises 20 parts of styrene, 74.8 parts of 2-ethylhexyl acrylate, 2 parts of methacrylic acid, 1.6 parts of N-methylolacrylamide, And 1.6 parts of acrylamide.
- Example 1 A lithium ion secondary battery was produced in the same manner as in Example 1 except that the following matters were changed, and measurements and evaluations on the lithium ion secondary battery and its components were performed.
- the monomer composition is composed of 10 parts of methacrylic acid (a carboxylic acid group-containing monomer) and 68 parts of ethyl acrylate (monomer (U1)).
- the monomer composition is composed of 60 parts of methacrylic acid (a carboxylic acid group-containing monomer) and 19 parts of ethyl acrylate (monomer (U1)). Parts, butyl acrylate (monomer (U2)) 19.2 parts, ethylene dimethacrylate (crosslinkable monomer) 0.8 parts, polyoxyalkylene alkenyl ether ammonium sulfate (reactive surfactant) 1.0 part It changed to become.
- Example 3 A lithium ion secondary battery was produced in the same manner as in Example 1 except that the following matters were changed, and measurements and evaluations on the lithium ion secondary battery and its components were performed. In the adjustment of the pH in the production of the porous membrane binder composition in the step (1-3), sodium hydroxide was added to adjust the pH to 7.5 instead of 6.0.
- Tables 1 to 3 show the evaluation results in Examples and Comparative Examples.
- MAA amount ratio of methacrylic acid added for preparation of polycarboxylic acid (A), unit by weight.
- EA amount ratio of ethyl acrylate added for the preparation of polycarboxylic acid (A), unit by weight.
- BA amount ratio of butyl acrylate added for the preparation of polycarboxylic acid (A), unit by weight.
- EDMA amount ratio of ethylene dimethacrylate added for preparation of polycarboxylic acid (A), unit by weight.
- Polycarboxylic acid pH pH of the prepared aqueous dispersion containing polycarboxylic acid (A).
- EA / BA ratio ratio of ethyl acrylate / butyl acrylate added for the preparation of polycarboxylic acid (A).
- Polycarboxylic acid Tg Glass transition temperature of the prepared polycarboxylic acid (A).
- pH 6.5 haze Haze of aqueous solution of prepared polycarboxylic acid (A) at pH 6.5.
- pH 8.0 haze Haze of aqueous solution of prepared polycarboxylic acid (A) at pH 8.0.
- Particulate polymer type The type of particulate polymer used.
- the particulate polymer P1 polymerizes a monomer composition comprising 92.8 parts of butyl acrylate, 2 parts of acrylonitrile, 2 parts of methacrylic acid, 1.6 parts of N-methylolacrylamide, and 1.6 parts of acrylamide; ) Acrylamide monomer ratio total 3.2 parts.
- the particulate polymer P2 is obtained by polymerizing a monomer composition comprising 95 parts of butyl acrylate, 2 parts of acrylonitrile, 2 parts of methacrylic acid, 0.5 part of N-methylolacrylamide, and 0.5 part of acrylamide; (meth) acrylamide Monomer proportions total 1.0 parts.
- the particulate polymer P3 polymerizes a monomer composition comprising 92.2 parts of butyl acrylate, 2 parts of acrylonitrile, 2 parts of methacrylic acid, 1.9 parts of N-methylolacrylamide, and 1.9 parts of acrylamide; ) Acrylamide monomer ratio total 3.8 parts.
- the particulate polymer P4 polymerizes a monomer composition comprising 20 parts of styrene, 74.8 parts of 2-ethylhexyl acrylate, 2 parts of methacrylic acid, 1.6 parts of N-methylolacrylamide, and 1.6 parts of acrylamide; (Meth) acrylamide monomer ratio total 3.2 parts.
- Particulate polycarboxylic acid ratio: The weight ratio of the amount of particulate polymer (corresponding to solid content) and the amount of polycarboxylic acid (A) (corresponding to solid content) used in the production of the binder composition for porous membrane.
- Binder pH pH of the produced binder composition for porous membranes.
- Slurry pH pH of the produced slurry.
- Slurry viscosity mPa ⁇ s viscosity of the produced slurry, unit mPa ⁇ s.
- the binder composition of the present invention containing the polycarboxylic acid (A) showed good storage stability, and the slurry for the porous film of the present invention prepared using the composition was coated.
- the porous film formed using the same exhibited a high adhesion strength, and the secondary battery produced using the porous film exhibited good high-temperature cycle characteristics.
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Abstract
Description
前記ポリカルボン酸は、カルボン酸基含有単量体単位を20質量%以上50質量%以下含み、
前記ポリカルボン酸は、pHが6.5以下で非水溶性、pHが8以上で水溶性であり、
前記二次電池多孔膜用バインダー組成物のpHが6.5以下である、二次電池多孔膜用バインダー組成物。
〔2〕 前記ポリカルボン酸は、アルキル(メタ)アクリレート単位を50質量%以上含む、〔1〕記載の二次電池多孔膜用バインダー組成物。
〔3〕 前記アルキル(メタ)アクリレート単位は炭素数1~3のアルキル基を有するアルキル(メタ)アクリレート単位(U1)と、炭素数4~6のアルキル基を有するアルキル(メタ)アクリレート単位(U2)とを含み、
前記ポリカルボン酸における前記単位(U1)と前記単位(U2)との重量比U1/U2が、1.0~10.0である〔2〕に記載の二次電池多孔膜用バインダー組成物。
〔4〕 前記ポリカルボン酸のガラス転移温度が30℃未満である、〔1〕~〔3〕のいずれか1項に記載の二次電池多孔膜用バインダー組成物。
〔5〕 非導電性粒子、ポリカルボン酸及び水を含む二次電池多孔膜用スラリーであって、
前記ポリカルボン酸は、カルボン酸基含有単量体単位を20質量%以上50質量%以下含み、
前記ポリカルボン酸は、pHが6.5以下で非水溶性、pHが8以上で水溶性であり、
前記二次電池多孔膜用スラリーのpHが7.0超過である、二次電池多孔膜用スラリー。
〔6〕 〔5〕に記載の二次電池多孔膜用スラリーの層を形成し、前記層を乾燥させてなる、二次電池用多孔膜。
〔7〕 〔6〕に記載の二次電池用多孔膜を備える二次電池。
本発明の二次電池多孔膜用バインダー組成物(以下において、単に「バインダー組成物」と呼ぶ場合がある。)は、特定のポリカルボン酸及び水を含む。この特定のポリカルボン酸を、以下において、ポリカルボン酸(A)と呼ぶ場合がある。
ポリカルボン酸(A)は、カルボン酸基含有単量体単位を所定割合含む重合体である。ポリカルボン酸(A)は、多孔膜において非導電性粒子同士の間に介在することにより非導電性粒子同士を結着する作用、並びに、非導電性粒子とセパレーター基材又は極板との間に介在することにより多孔膜とセパレーター基材又は極板とを結着する作用を奏しうる。
ポリカルボン酸(A)におけるカルボン酸基含有単量体単位とは、カルボン酸基含有単量体を重合して形成される構造を有する構造単位を示す。
ポリカルボン酸(A)は、好ましくは、アルキル(メタ)アクリレート単位を含む。アルキル(メタ)アクリレート単位とは、アルキル(メタ)アクリレートを重合して形成される構造を有する構造単位を示す。
アルキル(メタ)アクリレートの例としては、炭素数1~20のアルキル基を有するアルキル(メタ)アクリレートが挙げられる。なかでも、アルキル(メタ)アクリレートとして、炭素数1~10のアルキル基を有するアルキル(メタ)アクリレートであることが好ましく、より好ましくは炭素数1~6のアルキル基を有するアルキル(メタ)アクリレートであることがより好ましい。これらのアルキル(メタ)アクリレートのうち1種類、又は複数種類を組み合わせて、ポリカルボン酸(A)の重合のためのアルキル(メタ)アクリレートとして用いることができる。
ポリカルボン酸(A)は、架橋性単量体単位を含みうる。架橋性単量体単位を含むことにより、ポリカルボン酸(A)の分子量、物性等を適切な範囲に調節することができる。架橋性単量体単位とは、架橋性単量体を重合して形成される構造を有する構造単位を示す。架橋性単量体とは、重合により架橋構造を形成しうる単量体を表す。架橋性単量体の例としては、通常、熱架橋性を有する単量体が挙げられる。より具体的には、熱架橋性の架橋性基及び1分子あたり1つのオレフィン性二重結合を有する単官能性単量体;1分子あたり2つ以上のオレフィン性二重結合を有する多官能性単量体が挙げられる。
また、架橋性単量体及び架橋性単量体単位は、1種類を単独で用いてもよく、2種類以上を任意の比率で組み合わせて用いてもよい。
また、ポリカルボン酸(A)は、反応性界面活性剤単位を含むことが好ましい。反応性界面活性剤単位を含むことにより、ポリカルボン酸(A)の水に対する溶解性及びポリカルボン酸(A)の分散性を高めることができる。ここで、反応性界面活性剤単位とは、反応性界面活性剤単量体を重合して得られる構造を有する構造単位を表す。また、反応性界面活性剤単量体とは、他の単量体と共重合しうる重合性の基を有し、且つ、界面活性基(即ち、親水性基及び疎水性基)を有する単量体を表す。反応性界面活性剤単量体の重合により得られる反応性界面活性剤単位は、ポリカルボン酸(A)の分子の一部を構成し、且つ界面活性剤として機能しうる。
カチオン系の親水基の例としては、-NH2HXなどの第1級アミン塩、-NHCH3HXなどの第2級アミン塩、-N(CH3)2HXなどの第3級アミン塩、-N+(CH3)3X-などの第4級アミン塩、などが挙げられる。ここでXは、ハロゲン基を表す。
ノニオン系の親水基の例としては、-OHが挙げられる。
式(II)において、R3は親水性基を表す。R3の例としては、-SO3NH4が挙げられる。
式(II)において、nは1以上100以下の整数を表す。
反応性界面活性剤及び反応性界面活性剤単位は、1種類を単独で用いてもよく、2種類以上を任意の比率で組み合わせて用いてもよい。
ポリカルボン酸(A)は、本発明の効果を著しく損なわない限り、上述した単位以外の構造単位を含んでいてもよい。このような構造単位は、上述した単量体と共重合可能な単量体を重合して形成される構造単位としうる。また、これらは、1種類を単独で用いてもよく、2種類以上を任意の比率で組み合わせて用いてもよい。例えば、ポリカルボン酸(A)はフッ素含有(メタ)アクリル酸エステル単量体単位を含みうる。但し、多孔膜用スラリーの基材への塗布を良好に行う観点からは、ポリカルボン酸(A)におけるフッ素含有(メタ)アクリル酸エステル単量体単位の割合は、1重量%未満であることが好ましい。
一般にポリカルボン酸は、カルボン酸基を有するため、pHが高い水溶液中では高い水溶性を示し、pHが低い水溶液中では低い水溶性を示す傾向がある。本発明のポリカルボン酸(A)は、pHが6.5以下で非水溶性、pHが8以上で水溶性である。
非水溶性を示すpHの範囲の下限は、特に限定されないが、例えば1.0以上としうる。一方、水溶性を示すpHの範囲の上限も、特に限定されないが、例えば12.0以下としうる。
ポリカルボン酸(A)のpH6.5及びpH8における水溶性、非水溶性については、下記の通り判定する。
まず、ポリカルボン酸(A)の濃度10%、pH6.5の水溶液、及び濃度10%、pH8.0の水溶液を準備し、それぞれを25℃において1時間攪拌し、評価液とする。
前記評価液を光路長30mmのセルに移し、ヘーズメータを用い、散乱光及び全光線透過光を測定し、式:曇り度=散乱光/全光線透過光×100(%)で求められる、評価液の曇り度を求める。評価液の曇り度が60%以上である場合、ポリカルボン酸(A)が非水溶性であると判定し、60%未満である場合、ポリカルボン酸(A)が水溶性であると判定する。
一方、前述のポリカルボン酸(A)のpH8.0の水溶液の曇り度は、好ましくは50%未満であり、より好ましくは40%未満である。pH8.0でこのような低い曇り度即ち高い水溶性を呈するポリカルボン酸(A)を用いることにより、多孔膜用スラリーに十分な粘度を発現させ、塗布の不良の発生を低減し、多孔膜を備えた二次電池は、高いレート特性及び高い高温サイクル特性を達成することができる。pH8.0の水溶液の曇り度の下限は、特に限定されないが、例えば0%以上としうる。
さらに、このような、pH6.5の水溶液における性質及びpH8.0の水溶液における性質を兼ね備えるポリカルボン酸(A)を用いることにより、バインダー組成物の高い保存安定性と、使用時の適度な粘度との両方の利点を享受しうる。このような性質を有するポリカルボン酸(A)は、カルボン酸基含有単量体単位の割合やその他単量体単位の割合、種類などを適宜調節することにより得ることができる。
ポリカルボン酸(A)の製造方法としては、特に限定されないが、例えば、上述した単量体を含む単量体組成物を、水系溶媒中で重合して製造しうる。この際、単量体組成物中の各単量体の比率は、通常、ポリカルボン酸(A)における構造単位の比率と同様にする。
水系溶媒としては、例えば、水;ダイアセトンアルコール、γ-ブチロラクトン等のケトン類;エチルアルコール、イソプロピルアルコール、ノルマルプロピルアルコール等のアルコール類;プロピレングリコールモノメチルエーテル、メチルセロソルブ、エチルセロソルブ、エチレングリコールターシャリーブチルエーテル、ブチルセロソルブ、3-メトキシ-3-メチル-1-ブタノール、エチレングリコールモノプロピルエーテル、ジエチレングリコールモノブチルエーテル、トリエチレングリコールモノブチルエーテル、ジプロピレングリコールモノメチルエーテル等のグリコールエーテル類;1,3-ジオキソラン、1,4-ジオキソラン、テトラヒドロフラン等のエーテル類;などが挙げられる。中でも水は可燃性がなく、特に好ましい。また、主溶媒として水を使用して、上記記載の水以外の水系溶媒を混合して用いてもよい。
pHを調整する場合、ポリカルボン酸(A)の水分散液のpHは、好ましくは3.0以上、より好ましくは3.2以上、さらにより好ましくは3.5以上であり、一方好ましくは6.5以下である。ポリカルボン酸(A)の水分散液は、pHが低すぎると、他の材料と混合してpHが急に上昇した際に凝集し易くなり、一方pHが高すぎるとポリカルボン酸(A)が溶解して粒子状重合体との混合に際して凝集し易くなる。従って、pHを適切な範囲に調整することにより、良好な多孔膜用スラリーを得ることができる。
本発明のバインダー組成物は、ポリカルボン酸(A)に加えて、粒子状重合体を含みうる。バインダー組成物及び多孔膜用スラリーが粒子状重合体を含むことにより、通常は、以下のような利点を得られる。即ち、多孔膜の結着性が向上し、捲回時、運搬時等の取扱い時に本発明の二次電池用多孔膜を備えるセパレーター又は電極にかかる機械的な力に対する強度を向上させることができる。また、粒子状重合体は、その形状が粒子状であるので、多孔膜において非導電性粒子に対して面ではなく点で結着しうる。このため、多孔膜における孔を大きくできるので、二次電池の内部抵抗を小さくできる。
N-メチロールアミド基を含む単量体単位としては、N-メチロール(メタ)アクリルアミドが挙げられる。
N-メチロールアミド基を含む単量体単位を用いる場合、(メタ)アクリルアミドなどの一級アミンのアクリルアミドを併用することが好ましい。
前記第一級アミンのアクリルアミド単量体単位の割合は、N-メチロール基を有するアクリルアミド単量体単位の割合に対し、好ましくは50質量%以上200質量%以下である。前記の範囲とすることで、粒子状重合体が電解液へ溶出することを抑制し、良好な電池特性が得られるようになる。
なお、この場合、一級アミンのアクリルアミドは架橋性単量体単位に含まれる。
また、酸基含有単量体及び酸基含有単量体単位は、1種類を単独で用いてもよく、2種類以上を任意の比率で組み合わせて用いてもよい。
本発明のバインダー組成物は水を含む。水は、バインダー組成物において媒体即ち溶媒又は分散媒として機能する。通常、バインダー組成物では、非導電性粒子及び粒子状重合体は水に分散している。一方、ポリカルボン酸は、バインダー組成物のpHにより水に溶解するか又は分散している。
本発明の多孔膜用バインダー組成物は、そのpHが6.5以下である。pHの下限は、好ましくは5.0以上、より好ましくは5.2以上、さらに好ましくは5.5以上である。多孔膜用バインダー組成物のpHを前記下限以上とすることにより、ポリカルボン酸(A)の安定性が向上し、保存時における凝集を抑制することができ、ひいては、多孔膜を形成した際に、多孔膜と基材との密着強度を高くすることができる。多孔膜用バインダー組成物のpHを前記上限以下とすることにより、ポリカルボン酸(A)を非水溶性の状態に保ち、保存時における凝集を抑制することができ、安定性の高いバインダー組成物を得ることができる。多孔膜用バインダー組成物のpHは、酸性又は塩基性の成分を含む水溶液を添加することにより調整しうる。
本発明の多孔膜用バインダー組成物の調製方法は、特に限定されないが、例えば、上に述べた製造方法等の方法により、水系溶媒中で、ポリカルボン酸(A)の材料となる単量体を重合し、ポリカルボン酸(A)の水分散液を調製し、当該水分散液をそのまま、又は必要に応じてpHを上に述べた好ましい範囲に調整することにより、本発明の多孔膜用バインダー組成物としうる。または、当該水分散液に、必要に応じてさらに、上に述べた任意成分を添加し、その後pHを上に述べた好ましい範囲に調整することにより、本発明の多孔膜用バインダー組成物としうる。
本発明の二次電池多孔膜用スラリーは、非導電性粒子、ポリカルボン酸(A)及び水を含む。
非導電性粒子は、多孔膜に充填される成分であり、この非導電性粒子同士の隙間が多孔膜の孔を形成しうる。非導電性粒子が非導電性を有するので、多孔膜を絶縁性にでき、そのため、二次電池における短絡を防止することができる。また、通常、非導電性粒子は高い剛性を有し、これにより、多孔膜の機械的強度を高めることができる。そのため、熱によってセパレーター基材等の基材に収縮しようとする応力が生じた場合でも、多孔膜がその応力に抗することができるので、基材の収縮による短絡の発生を防止することが可能である。
非導電性粒子としては、無機粒子を用いてもよく、有機粒子を用いてもよい。
本発明の多孔膜用スラリーは水を含む。また、媒体として、水以外の媒体を水とを組み合わせて用いてもよい。水と組み合わせて用いうる媒体の例及びこれらと水との比率の例としては、バインダー組成物における媒体の場合と同様のものが挙げられる。多孔膜用スラリーにおける水の量は、特に限定されず、多孔膜用スラリーの物性が好ましい範囲となるよう適宜調節しうる。
本発明の多孔膜用スラリーは、上述した成分以外に、任意の成分を含みうる。このような任意の成分としては、電池反応に過度に好ましくない影響を及ぼさないものを用いうる。任意の成分としては、1種類を単独で用いてもよく、2種類以上を任意の比率で組み合わせて用いてもよい。
カルボキシメチルセルロース塩等の水溶性増粘剤は、多孔膜用スラリーの粘度を高めることができるので、多孔膜用スラリーの塗布性を良好にすることができる。また、カルボキシメチルセルロース塩により、通常は、多孔膜用スラリーにおける非導電性粒子の分散安定性を高めたり、多孔膜とセパレータ基材又は極板との結着性を高めたりすることができる。カルボキシメチルセルロース塩としては、例えば、ナトリウム塩、アンモニウム塩などが挙げられる。また、カルボキシメチルセルロース塩は、1種類を単独で用いてもよく、2種類以上を任意の比率で組み合わせて用いてもよい。
本発明の多孔膜用スラリーのpHは7.0超過であり、好ましくは7.5以上、より好ましくは8.0以上であり、さらにより好ましくは8.5以上である。スラリーのpHをこの範囲とすることにより、ポリカルボン酸(A)を水溶性の状態とし、その増粘効果により、多孔膜用スラリーに十分な粘度を発現させ、塗布の不良の発生を低減し、高い高温サイクル特性を達成することができる。pHの上限は、特に限定されないが、例えば12.0としうる。多孔膜用スラリーのpHは、ポリカルボン酸及びその他の成分の含有量を調整することにより、また必要に応じて多孔膜用スラリーの製造に際してpHを調整する酸性又は塩基性の成分を添加することにより調整しうる。
本発明の多孔膜用スラリーは、任意の製造方法で製造しうるが、本発明の多孔膜用スラリーの製造方法の好ましい例としては、前記本発明のバインダー組成物とその他の成分を混合する方法が挙げられる。特に、各成分の混合に際して、ポリカルボン酸(A)及び粒子状重合体の全てを、これらを含む多孔膜用バインダー組成物を添加することにより供給することが好ましい。
混合に際して、必要に応じて、分散機を用いて、上記成分、特に非導電性粒子を、多孔膜用スラリー中に分散させることができる。分散機としては、メディアレス分散機を用いることが、非導電性粒子の粒径を不所望に小さくすることが少ないため好ましい。
さらに、かかる混合の前又は混合の後に、必要に応じてpHを調整しうる。pHの調整は、酸又は塩基を適宜添加することにより行ないうる。
本発明の二次電池用多孔膜(以下において単に本発明の多孔膜という場合がある。)は、前記本発明の二次電池多孔膜用スラリーの層を形成し、これを乾燥させてなる。
例えば、金型プレス及びロールプレス等のプレス方法によって、多孔膜に加圧処理を施してもよい。加圧処理を施すことにより、基材と多孔膜との結着性を向上させることができる。ただし、多孔膜の空隙率を好ましい範囲に保つ観点では、圧力および加圧時間が過度に大きくならないように適切に制御することが好ましい。
また、残留水分除去のため、例えば真空乾燥やドライルーム内で乾燥することが好ましい。
基材として、セパレーター基材を用いた場合、セパレーター基材及び本発明の多孔膜を備える二次電池用セパレーターが得られる。本発明の多孔膜は、セパレーター基材の片方の面だけに設けられていてもよく、両方の面に設けられていてもよい。
二次電池において、セパレーターとして本発明の多孔膜を備えるセパレーターを用いた場合、多孔膜中の残存水分量が少なく、多孔膜の熱収縮が少なく、且つ多孔膜と基材との密着強度を高くしうるため、二次電池の高温サイクル特性を向上させることができる。
基材として極板を用いた場合、極板及び本発明の多孔膜を備える二次電池用電極が得られる。本願において、「極板」とは、多孔膜を備える電極のうち、多孔膜以外の部材をいう。極板は、通常、集電体及び電極活物質層を備える。極板及び本発明の多孔膜を備える二次電池用電極は、通常、集電体、電極活物質層及び本発明の多孔膜をこの順に備える。例えば、極板において、集電体の片面のみに電極活物質層が設けられている場合、集電体/電極活物質層/多孔膜の層構成をとりうる。また例えば、極板において、集電体の両面に電極活物質層が設けられている場合、多孔膜/電極活物質層/集電体/電極活物質層/多孔膜の層構成をとりうる。
極板の集電体としては、電気導電性を有し、且つ、電気化学的に耐久性のある材料を用いうる。通常、この集電体の材料としては、金属材料を用いる。その例を挙げると、鉄、銅、アルミニウム、ニッケル、ステンレス鋼、チタン、タンタル、金、白金などが挙げられる。中でも、正極に用いる集電体としてはアルミニウムが好ましく、負極に用いる集電体としては銅が好ましい。また、前記の材料は、1種類を単独で用いてもよく、2種類以上を任意の比率で組み合わせて用いてもよい。
電極活物質層は、集電体上に設けられた層であり、電極活物質を含む。電極活物質の種類は二次電池の種類に応じて様々であり、ここでは、特にリチウムイオン二次電池用の電極活物質について説明する。ただし、電極活物質は以下で挙げるものに限定されない。
また、例えば、鉄系酸化物を炭素源物質の存在下において還元焼成することで、炭素材料で覆われた複合材料を作製し、この複合材料を正極活物質として用いてもよい。鉄系酸化物は電気伝導性に乏しい傾向があるが、前記のような複合材料にすることにより、高性能な正極活物質として使用できる。
さらに、前記の化合物を部分的に元素置換したものを正極活物質として用いてもよい。
これらの正極活物質は、1種類を単独で用いてもよく、2種類以上を任意の比率で組み合わせて用いてもよい。また、前述の無機化合物と有機化合物との混合物を正極活物質として用いてもよい。
(i)ポリブチルアクリレート、ポリブチルメタクリレート、ポリヒドロキシエチルメタクリレート、ポリアクリルアミド、ポリアクリロニトリル、ブチルアクリレート・スチレン共重合体、ブチルアクリレート・アクリロニトリル共重合体、ブチルアクリレート・アクリロニトリル・グリシジルメタクリレート共重合体などの、アクリル酸またはメタクリル酸誘導体の単独重合体またはそれと共重合可能な単量体との共重合体である、アクリル系軟質重合体;
(ii)ポリイソブチレン、イソブチレン・イソプレンゴム、イソブチレン・スチレン共重合体などのイソブチレン系軟質重合体;
(iii)ポリブタジエン、ポリイソプレン、ブタジエン・スチレンランダム共重合体、イソプレン・スチレンランダム共重合体、アクリロニトリル・ブタジエン共重合体、アクリロニトリル・ブタジエン・スチレン共重合体、ブタジエン・スチレン・ブロック共重合体、スチレン・ブタジエン・スチレン・ブロック共重合体、イソプレン・スチレン・ブロック共重合体、スチレン・イソプレン・スチレン・ブロック共重合体などジエン系軟質重合体;
(iv)ジメチルポリシロキサン、ジフェニルポリシロキサン、ジヒドロキシポリシロキサンなどのケイ素含有軟質重合体;
(v)液状ポリエチレン、ポリプロピレン、ポリ-1-ブテン、エチレン・α-オレフィン共重合体、プロピレン・α-オレフィン共重合体、エチレン・プロピレン・ジエン共重合体(EPDM)、エチレン・プロピレン・スチレン共重合体などのオレフィン系軟質重合体;
(vi)ポリビニルアルコール、ポリ酢酸ビニル、ポリステアリン酸ビニル、酢酸ビニル・スチレン共重合体などビニル系軟質重合体;
(vii)ポリエチレンオキシド、ポリプロピレンオキシド、エピクロルヒドリンゴムなどのエポキシ系軟質重合体;
(viii)フッ化ビニリデン系ゴム、四フッ化エチレン-プロピレンゴムなどのフッ素含有軟質重合体;
(ix)天然ゴム、ポリペプチド、蛋白質、ポリエステル系熱可塑性エラストマー、塩化ビニル系熱可塑性エラストマー、ポリアミド系熱可塑性エラストマーなどのその他の軟質重合体;などが挙げられる。これらの軟質重合体は、架橋構造を有したものであってもよく、変性により官能基を導入したものであってもよい。
また、前記の重合体は、粒子状であってもよく、非粒子状であってもよい。
さらに、電極用バインダーは、1種類を単独で用いてもよく、2種類以上を任意の比率で組み合わせて用いてもよい。
本発明の二次電池は、前記本発明の多孔膜を備える。二次電池は、通常、正極、負極及び電解液を備え、下記の要件(A)を満たすか、要件(B)を満たすか、要件(A)及び(B)の両方を満たす。
(A)本発明の二次電池の正極及び負極の少なくとも一方が、極板及び本発明の多孔膜を備える電極である。
(B)本発明の二次電池がセパレーターを備え、且つ、そのセパレーターがセパレーター基材及び本発明の多孔膜を備えるセパレーターである。
本発明の二次電池は、原則として、セパレーターとして本発明の多孔膜を備えるセパレーターを備える。ただし、本発明の二次電池が正極及び負極の少なくとも一方として本発明の多孔膜を備えるものを備える場合には、セパレーターとして本発明の多孔膜を備えるセパレーター以外のセパレーターを備えていてもよい。また、本発明の多孔膜を備える電極における多孔膜はセパレーターとしての機能を有するので、電極が本発明の多孔膜を備える場合、セパレーターを省略してもよい。
本発明の二次電池は、原則として、正極及び負極の一方又は両方として、本発明の多孔膜を備える電極を備える。ただし、本発明の二次電池がセパレーターとして本発明の多孔膜を備えるセパレーターを備える場合には、正極及び負極の両方として本発明の多孔膜を備えない電極を備えていてもよい。
電解液としては、例えば、非水系の溶媒に支持電解質としてリチウム塩を溶解したものを使用しうる。リチウム塩としては、例えば、LiPF6、LiAsF6、LiBF4、LiSbF6、LiAlCl4、LiClO4、CF3SO3Li、C4F9SO3Li、CF3COOLi、(CF3CO)2NLi、(CF3SO2)2NLi、(C2F5SO2)NLiなどが挙げられる。特に溶媒に溶けやすく高い解離度を示すLiPF6、LiClO4、CF3SO3Liは好適に用いられる。これらは1種類を単独で用いてもよく、2種類以上を任意の比率で組み合わせて用いてもよい。
本発明の二次電池の製造方法は、特に限定されない。例えば、上述した負極と正極とをセパレーターを介して重ね合わせ、これを電池形状に応じて巻く、折るなどして電池容器に入れ、電池容器に電解液を注入して封口してもよい。さらに、必要に応じてエキスパンドメタル;ヒューズ、PTC素子などの過電流防止素子;リード板などを入れ、電池内部の圧力上昇、過充放電の防止をしてもよい。電池の形状は、例えば、ラミネートセル型、コイン型、ボタン型、シート型、円筒型、角形、扁平型などいずれであってもよい。
ポリカルボン酸(A)を50%湿度、25℃の環境下で3日間乾燥させて、厚み1.0mmのフィルムを得た。このフィルムを、60℃真空乾燥機で10時間乾燥させた。その後、乾燥させたフィルムをサンプルとして、JIS K 7121に準じて、測定温度-100℃~180℃、昇温速度5℃/分の条件下、DSC6220SII(示差走査熱量分析計、ナノテクノロジー社製)を用いてガラス転移温度(℃)を測定した。
多孔膜用スラリーの粘度は、B型粘度計を用いて25℃、回転数60rpmで測定した。
卓上型pHメーター(HORIBA製F-51)を、pH標準液(pH4、pH7及びpH9)で校正した後、これを用いて、試料のpHを測定した。
実施例及び比較例で得られたセパレーターを、幅10mm×長さ100mmの長方形に切り出し、試験片とした。試験片の多孔膜面にセロハンテープ(JIS Z1522に規定されるもの)を貼り付けた。セロハンテープを試験台の水平面に、平らな状態に固定し、セパレーターの一端を、セロハンテープ面に対して垂直方向に引張り速度10mm/分で引張って剥がし、そのときの応力を測定した。測定を3回行い、その平均値を求めてこれをピール強度とし、下記の基準により評価した。ピール強度が大きいほど、多孔膜とセパレーター基材との結着力が大きい、すなわち密着強度が大きいことを示す。
B:ピール強度が150N/m以上200N/m未満
C:ピール強度が100N/m以上150N/m未満
D:ピール強度が100N/m未満
バインダー組成物を100ml容器に100ml入れ、1週間静置保存した。
静置保存後、バインダー組成物の上澄みの固形分濃度を測定し、下記の式で表される固形分濃度維持率を求め、下記の基準により評価した。固形分濃度維持率が大きいほど、沈降速度が遅い、すなわちバインダー組成物の安定性が高いことを示す。
固形分濃度維持率(%)=(保存後の上澄み中の固形分濃度/保存前のバインダー組成物の固形分濃度)×100
B:固形分濃度維持率が90%以上95%未満
C:固形分濃度維持率が85%以上90%未満
D:固形分濃度維持率が85%未満
実施例および比較例で得られたリチウムイオン二次電池を、25℃の環境下で24時間静置させた後に、25℃の環境下で、4.35V、0.1Cの充電、2.75V、0.1Cの放電にて充放電の操作を行い、初期容量C0を測定した。さらに、60℃環境下で、4.35V、0.1Cの充電、及び2.75V、0.1Cの放電を1サイクルとする充放電のサイクルを繰り返し、1000サイクル後の容量C1を測定した。C0及びC1の値から、容量維持率を、式ΔC=(C1/C0)×100(%)により求め、下記の基準により評価した。この値が高いほど高温サイクル特性に優れることを示す。
(評価基準)
A:容量維持率が70%以上
B:容量維持率が60%以上70%未満
C:容量維持率が50%以上60%未満
D:容量維持率が50%未満
実施例及び比較例で得られたポリカルボン酸(A)の水分散液の濃度及びpHを調整し、濃度10%、pH6.5の水溶液、及び濃度10%、pH8.0の水溶液を準備し、それぞれを25℃において1時間攪拌し、評価液とした。
前記評価液を光路長30mmのセルに移し、ヘーズメータを用い、散乱光及び全光線透過光を測定し、式:曇り度=散乱光/全光線透過光×100(%)で求められる、評価液の曇り度を求めた。評価液の曇り度が60%以上である場合、ポリカルボン酸(A)が水溶性であると判定し、60%未満である場合、ポリカルボン酸(A)が非水溶性であると判定した。
(1-1.ポリカルボン酸(A)の調製)
攪拌機付き5MPa耐圧容器に、単量体組成物100.0部、イオン交換水150部、及び過硫酸カリウム(重合開始剤)1.0部を入れ、十分に攪拌した後、60℃に加温して重合を開始した。単量体組成物は、メタクリル酸(カルボン酸基含有単量体)30部、エチルアクリレート(単量体(U1))56部、ブチルアクリレート(単量体(U2))12.2部、エチレンジメタクリレート(架橋性単量体)0.8部、ポリオキシアルキレンアルケニルエーテル硫酸アンモニウム(反応性界面活性剤、商品名「ラテムルPD-104」(花王株式会社製))1.0部からなるものとした。重合転化率が96%になった時点で冷却し反応を停止して、さらに水酸化ナトリウム水溶液を添加してpHを4.0に調整し、ポリカルボン酸(A)を含む水分散液を得た。
得られたポリカルボン酸(A)について、pH6.5及び8.0における水溶性を評価した。
攪拌機付き5MPa耐圧容器に、単量体組成物100.0部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム0.4部、イオン交換水150部及び重合開始剤として過硫酸カリウム0.3部を入れ、十分に攪拌した後、50℃に加温して重合を開始した。単量体組成物は、ブチルアクリレート92.8部、アクリロニトリル2部、メタクリル酸2部、N-メチロールアクリルアミド1.6部、及びアクリルアミド1.6部からなるものとした。重合転化率が96%になった時点で冷却し反応を停止して、粒子状重合体を含む混合物を得た。上記粒子状重合体を含む混合物に、5%水酸化ナトリウム水溶液を添加して、pH6.5に調整し、所望の粒子状重合体を含む水分散液を得た。
工程(1-2)で得られた粒子状重合体を含む水分散液90部(固形分相当)、及び工程(1-1)で得られたポリカルボン酸(A)を含む水分散液10部(固形分相当)混合し、多孔膜用バインダー組成物を得た。
得られた多孔膜用バインダー組成物について、pHを測定した。また、多孔膜用バインダー組成物の安定性を評価した。
非導電性粒子としてアルミナ粒子(体積平均粒径0.5μm、BET比表面積5.0m2/g)100部、カルボキシメチルセルロースナトリウム塩(ダイセル社製、製品名「ダイセル1220」)2部、及び前記工程(1-3)で得た多孔膜用バインダー組成物6部(固形分相当)を混合し、更に水を混合して固形分濃度が40重量%になるように調整し、さらに水酸化ナトリウム水溶液を添加してpHを9.0に調整し、多孔膜用スラリーを製造した。
得られた多孔膜用スラリーについて、pH及び粘度を測定した。
単層のポリプロピレン製のセパレータ基材(セルガード社製、商品名「セルガード2500」)の一方の面上に、前記工程(1-4)で得た多孔膜用スラリーを、グラビアコーターで、乾燥後の塗布量が6mg/cm2となるように塗布し、乾燥させた。この乾燥は、セパレータ基材を20m/分の速度で100℃のオーブン内を1分間かけて搬送することにより行った。これにより、セパレータ基材及びその一方の面上に形成された多孔膜を備えるセパレータを得た。
得られたセパレーターについて、密着強度を評価した。
正極活物質としてLiCoO2(体積平均粒子径D50:12μm)を100部、導電材としてアセチレンブラック(電気化学工業社製、HS-100)を2部、正極活物質層用結着剤としてPVDF(ポリフッ化ビニリデン、クレハ社製、#7208)を固形分相当で2部、及びNMP(N-メチルピロリドン)を混合し全固形分濃度が70%となる量とした。これらをプラネタリーミキサーにより混合し、正極用スラリー組成物を得た。
得られた正極用スラリー組成物を、コンマコーターで、集電体である厚さ20μmのアルミ箔の上に、乾燥後の膜厚が150μm程度になるように塗布し、乾燥させた。この乾燥は、アルミ箔を0.5m/分の速度で60℃のオーブン内を2分間かけて搬送することにより行った。その後、正極原反をロールプレスで圧延して、正極活物質層の厚みが95μmの正極を得た。
攪拌機付き5MPa耐圧容器に、1,3-ブタジエン33.5部、イタコン酸3.5部、スチレン62部、2-ヒドロキシエチルアクリレート1部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム0.4部、イオン交換水150部及び重合開始剤としてペルオキソ二硫酸カリウム0.5部を入れ、十分に攪拌した後、50℃に加温して重合を開始した。重合転化率が96%になった時点で冷却し反応を停止して、負極活物質層用結着剤(SBR)を含む混合物を得た。上記負極活物質層用結着剤を含む混合物に、5%水酸化ナトリウム水溶液を添加して、pH8に調整した後、加熱減圧蒸留によって未反応単量体の除去を行った。その後、30℃以下まで冷却し、所望の負極活物質層用結着剤を含む水分散液を得た。
人造黒鉛(体積平均粒子径D50:15.6μm)100部と、増粘剤としてのカルボキシメチルセルロースのナトリウム塩(日本製紙社製、MAC350HC)の2%水溶液を固形分相当で1部との混合物をイオン交換水で固形分濃度68%に調製した後、25℃で60分間混合した。さらにイオン交換水で固形分濃度62%に調整した後、25℃で15分間混合した。上記の負極活物質層用結着剤(SBR)を固形分相当量で1.5部、及びイオン交換水を入れ、最終固形分濃度52%となるように調整し、さらに10分間混合した。これを減圧下で脱泡処理して流動性の良い負極用スラリー組成物を調製した。
得られた負極用スラリー組成物を、コンマコーターで、集電体である厚さ20μmの銅箔の上に、乾燥後の膜厚が150μm程度になるように塗布し、乾燥させた。この乾燥は、銅箔を0.5m/分の速度で60℃のオーブン内を2分間かけて搬送することにより行った。その後、負極原反をロールプレスで圧延して、負極活物質層の厚みが100μmの負極を得た。
電池の外装として、アルミニウム包材外装を用意した。工程(1-6)で得られた正極を、4.6cm×4.6cmの正方形に切り出し、矩形の正極を得た。工程(1-5)で得られたセパレーターを、5.5cm×5.5cmの正方形に切り出し、矩形のセパレーターを得た。さらに、工程(1-7)で得られた負極を、5cm×5cmの正方形に切り出し、矩形の負極を得た。矩形の正極を、その集電体側の表面がアルミニウム包材外装に接するように、包材外装内に配置した。矩形の正極の正極活物質層側の面上に、矩形のセパレーターを、多孔膜側の面が矩形の正極に接するよう配置した。さらに、矩形の負極を、セパレーター上に、負極活物質層側の表面がセパレーターに向かい合うよう配置した。電解液(溶媒:EC/EMC/VC=68.5/30/1.5体積比、電解質:濃度1MのLiPF6)を空気が残らないように注入した。さらに、アルミニウム包材の開口を密封するために、150℃のヒートシールをしてアルミニウム包材外装を閉口し、リチウムイオン二次電池を製造した。
このリチウムイオン二次電池について、高温サイクル特性を評価した。
下記の事項を変更した他は、実施例1と同様にして、リチウムイオン二次電池を製造し、リチウムイオン二次電池及びその構成要素についての測定及び評価を行なった。
・工程(1-1)のポリカルボン酸(A)の製造において、単量体組成物を、メタクリル酸(カルボン酸基含有単量体)28部、エチルアクリレート(単量体(U1))58部、ブチルアクリレート(単量体(U2))12.2部、エチレンジメタクリレート(架橋性単量体)0.8部、ポリオキシアルキレンアルケニルエーテル硫酸アンモニウム(反応性界面活性剤)1.0部からなるものに変更した。
下記の事項を変更した他は、実施例1と同様にして、リチウムイオン二次電池を製造し、リチウムイオン二次電池及びその構成要素についての測定及び評価を行なった。
・工程(1-1)のポリカルボン酸(A)の製造において、単量体組成物を、メタクリル酸(カルボン酸基含有単量体)35部、エチルアクリレート(単量体(U1))45.5部、ブチルアクリレート(単量体(U2))17.7部、エチレンジメタクリレート(架橋性単量体)0.8部、ポリオキシアルキレンアルケニルエーテル硫酸アンモニウム(反応性界面活性剤)1.0部からなるものに変更した。
下記の事項を変更した他は、実施例1と同様にして、リチウムイオン二次電池を製造し、リチウムイオン二次電池及びその構成要素についての測定及び評価を行なった。
・工程(1-1)のポリカルボン酸(A)の製造において、単量体組成物を、メタクリル酸(カルボン酸基含有単量体)22部、エチルアクリレート(単量体(U1))56部、ブチルアクリレート(単量体(U2))20.2部、エチレンジメタクリレート(架橋性単量体)0.8部、ポリオキシアルキレンアルケニルエーテル硫酸アンモニウム(反応性界面活性剤)1.0部からなるものに変更した。
下記の事項を変更した他は、実施例1と同様にして、リチウムイオン二次電池を製造し、リチウムイオン二次電池及びその構成要素についての測定及び評価を行なった。
・工程(1-1)のポリカルボン酸(A)の製造において、単量体組成物を、メタクリル酸(カルボン酸基含有単量体)44部、エチルアクリレート(単量体(U1))29部、ブチルアクリレート(単量体(U2))25.2部、エチレンジメタクリレート(架橋性単量体)0.8部、ポリオキシアルキレンアルケニルエーテル硫酸アンモニウム(反応性界面活性剤)1.0部からなるものに変更した。
下記の事項を変更した他は、実施例1と同様にして、リチウムイオン二次電池を製造し、リチウムイオン二次電池及びその構成要素についての測定及び評価を行なった。
・工程(1-1)のポリカルボン酸(A)の製造において、反応停止後のpHの調整を行わず、pH3.3の、ポリカルボン酸の水分散液を得た。これをそのまま、その後の工程においてポリカルボン酸の水分散液として用いた。
下記の事項を変更した他は、実施例1と同様にして、リチウムイオン二次電池を製造し、リチウムイオン二次電池及びその構成要素についての測定及び評価を行なった。
・工程(1-1)のポリカルボン酸(A)の製造のpHの調整において、水酸化ナトリウム水溶液を添加して、pHを、4.0ではなく6.4に調整した。
・工程(1-2)の粒子状重合体の調製のpH調整において、水酸化ナトリウム水溶液を添加して、pHを、6.5ではなく6.4に調整した。
下記の事項を変更した他は、実施例1と同様にして、リチウムイオン二次電池を製造し、リチウムイオン二次電池及びその構成要素についての測定及び評価を行なった。
・工程(1-1)のポリカルボン酸(A)の製造において、単量体組成物を、メタクリル酸(カルボン酸基含有単量体)30部、エチルアクリレート(単量体(U1))34部、ブチルアクリレート(単量体(U2))34.2部、エチレンジメタクリレート(架橋性単量体)0.8部、ポリオキシアルキレンアルケニルエーテル硫酸アンモニウム(反応性界面活性剤)1.0部からなるものに変更した。
下記の事項を変更した他は、実施例1と同様にして、リチウムイオン二次電池を製造し、リチウムイオン二次電池及びその構成要素についての測定及び評価を行なった。
・工程(1-1)のポリカルボン酸(A)の製造において、単量体組成物を、メタクリル酸(カルボン酸基含有単量体)30部、エチルアクリレート(単量体(U1))59.5部、ブチルアクリレート(単量体(U2))8.7部、エチレンジメタクリレート(架橋性単量体)0.8部、ポリオキシアルキレンアルケニルエーテル硫酸アンモニウム(反応性界面活性剤)1.0部からなるものに変更した。
下記の事項を変更した他は、実施例1と同様にして、リチウムイオン二次電池を製造し、リチウムイオン二次電池及びその構成要素についての測定及び評価を行なった。
・工程(1-1)のポリカルボン酸(A)の製造において、単量体組成物を、メタクリル酸(カルボン酸基含有単量体)35部、エチルアクリレート(単量体(U1))51部、ブチルアクリレート(単量体(U2))12.2部、エチレンジメタクリレート(架橋性単量体)0.8部、ポリオキシアルキレンアルケニルエーテル硫酸アンモニウム(反応性界面活性剤)1.0部からなるものに変更した。
下記の事項を変更した他は、実施例1と同様にして、リチウムイオン二次電池を製造し、リチウムイオン二次電池及びその構成要素についての測定及び評価を行なった。
・工程(1-2)の粒子状重合体の製造において、単量体組成物を、ブチルアクリレート95部、アクリロニトリル2部、メタクリル酸2部、N-メチロールアクリルアミド0.5部、及びアクリルアミド0.5部からなるものに変更した。
下記の事項を変更した他は、実施例1と同様にして、リチウムイオン二次電池を製造し、リチウムイオン二次電池及びその構成要素についての測定及び評価を行なった。
・工程(1-2)の粒子状重合体の製造において、単量体組成物を、ブチルアクリレート92.2部、アクリロニトリル2部、メタクリル酸2部、N-メチロールアクリルアミド1.9部、及びアクリルアミド1.9部からなるものに変更した。
下記の事項を変更した他は、実施例1と同様にして、リチウムイオン二次電池を製造し、リチウムイオン二次電池及びその構成要素についての測定及び評価を行なった。
・工程(1-3)の多孔膜用バインダー組成物の製造において、工程(1-2)で得られた粒子状重合体を含む水分散液の割合を98部(固形分相当)、及び工程(1-1)で得られたポリカルボン酸(A)を含む水分散液の割合を2部(固形分相当)とした。
下記の事項を変更した他は、実施例1と同様にして、リチウムイオン二次電池を製造し、リチウムイオン二次電池及びその構成要素についての測定及び評価を行なった。
・工程(1-3)の多孔膜用バインダー組成物の製造において、工程(1-2)で得られた粒子状重合体を含む水分散液の割合を55部(固形分相当)、及び工程(1-1)で得られたポリカルボン酸(A)を含む水分散液の割合を45部(固形分相当)とした。
下記の事項を変更した他は、実施例1と同様にして、リチウムイオン二次電池を製造し、リチウムイオン二次電池及びその構成要素についての測定及び評価を行なった。
・工程(1-2)の粒子状重合体の調製のpH調整において、水酸化ナトリウム水溶液を添加して、pHを、6.5ではなく5.5に調整した。
下記の事項を変更した他は、実施例1と同様にして、リチウムイオン二次電池を製造し、リチウムイオン二次電池及びその構成要素についての測定及び評価を行なった。
・工程(1-4)多孔膜用スラリーの製造のpHの調整において、水酸化ナトリウム水溶液を添加して、pHを9.0ではなく7.1に調整した。
下記の事項を変更した他は、実施例1と同様にして、リチウムイオン二次電池を製造し、リチウムイオン二次電池及びその構成要素についての測定及び評価を行なった。
・工程(1-2)の粒子状重合体の製造において、単量体組成物を、スチレン20部、2-エチルヘキシルアクリレート74.8部、メタクリル酸2部、N-メチロールアクリルアミド1.6部、及びアクリルアミド1.6部からなるものに変更した。
下記の事項を変更した他は、実施例1と同様にして、リチウムイオン二次電池を製造し、リチウムイオン二次電池及びその構成要素についての測定及び評価を行なった。
・工程(1-1)のポリカルボン酸(A)の製造において、単量体組成物を、メタクリル酸(カルボン酸基含有単量体)10部、エチルアクリレート(単量体(U1))68部、ブチルアクリレート(単量体(U2))20.2部、エチレンジメタクリレート(架橋性単量体)0.8部、ポリオキシアルキレンアルケニルエーテル硫酸アンモニウム(反応性界面活性剤)1.0部からなるものに変更した。
下記の事項を変更した他は、実施例1と同様にして、リチウムイオン二次電池を製造し、リチウムイオン二次電池及びその構成要素についての測定及び評価を行なった。
・工程(1-1)のポリカルボン酸(A)の製造において、単量体組成物を、メタクリル酸(カルボン酸基含有単量体)60部、エチルアクリレート(単量体(U1))19部、ブチルアクリレート(単量体(U2))19.2部、エチレンジメタクリレート(架橋性単量体)0.8部、ポリオキシアルキレンアルケニルエーテル硫酸アンモニウム(反応性界面活性剤)1.0部からなるものに変更した。
下記の事項を変更した他は、実施例1と同様にして、リチウムイオン二次電池を製造し、リチウムイオン二次電池及びその構成要素についての測定及び評価を行なった。
・工程(1-3)の多孔膜用バインダー組成物の製造のpHの調整において、水酸化ナトリウムを添加して、pHを6.0ではなく7.5に調整した。
MAA量:ポリカルボン酸(A)の調製のために添加したメタクリル酸の割合、単位重量部。
EA量:ポリカルボン酸(A)の調製のために添加したエチルアクリレートの割合、単位重量部。
BA量:ポリカルボン酸(A)の調製のために添加したブチルアクリレートの割合、単位重量部。
EDMA量:ポリカルボン酸(A)の調製のために添加したエチレンジメタクリレートの割合、単位重量部。
ポリカルボン酸pH:調製した、ポリカルボン酸(A)を含む水分散液のpH。
EA/BA比:ポリカルボン酸(A)の調製のために添加したエチルアクリレート/ブチルアクリレートの比。
ポリカルボン酸Tg:調製したポリカルボン酸(A)のガラス転移温度。
pH6.5曇り度:調製したポリカルボン酸(A)のpH6.5の水溶液の曇り度。
pH8.0曇り度:調製したポリカルボン酸(A)のpH8.0の水溶液の曇り度。
粒子状重合体種類:使用した粒子状重合体の種類。
粒子状重合体P1は、ブチルアクリレート92.8部、アクリロニトリル2部、メタクリル酸2部、N-メチロールアクリルアミド1.6部、及びアクリルアミド1.6部からなる単量体組成物を重合;(メタ)アクリルアミド単量体割合合計3.2部。
粒子状重合体P2は、ブチルアクリレート95部、アクリロニトリル2部、メタクリル酸2部、N-メチロールアクリルアミド0.5部、及びアクリルアミド0.5部からなる単量体組成物を重合;(メタ)アクリルアミド単量体割合合計1.0部。
粒子状重合体P3は、ブチルアクリレート92.2部、アクリロニトリル2部、メタクリル酸2部、N-メチロールアクリルアミド1.9部、及びアクリルアミド1.9部からなる単量体組成物を重合;(メタ)アクリルアミド単量体割合合計3.8部。
粒子状重合体P4は、スチレン20部、2-エチルヘキシルアクリレート74.8部、メタクリル酸2部、N-メチロールアクリルアミド1.6部、及びアクリルアミド1.6部からなる単量体組成物を重合;(メタ)アクリルアミド単量体割合合計3.2部。
粒子状:ポリカルボン酸比:多孔膜用バインダー組成物の製造において用いた、粒子状重合体量(固形分相当)とポリカルボン酸(A)量(固形分相当)の重量比。
バインダーpH:製造した多孔膜用バインダー組成物のpH。
スラリーpH:製造したスラリーのpH。
スラリー粘度mPa・s:製造したスラリーの粘度、単位mPa・s。
Claims (7)
- ポリカルボン酸及び水を含む二次電池多孔膜用バインダー組成物であって、
前記ポリカルボン酸は、カルボン酸基含有単量体単位を20質量%以上50質量%以下含み、
前記ポリカルボン酸は、pHが6.5以下で非水溶性、pHが8以上で水溶性であり、
前記二次電池多孔膜用バインダー組成物のpHが6.5以下である、二次電池多孔膜用バインダー組成物。 - 前記ポリカルボン酸は、アルキル(メタ)アクリレート単位を50質量%以上含む、請求項1記載の二次電池多孔膜用バインダー組成物。
- 前記アルキル(メタ)アクリレート単位は炭素数1~3のアルキル基を有するアルキル(メタ)アクリレート単位(U1)と、炭素数4~6のアルキル基を有するアルキル(メタ)アクリレート単位(U2)とを含み、
前記ポリカルボン酸における前記単位(U1)と前記単位(U2)との重量比U1/U2が、1.0~10.0である請求項2に記載の二次電池多孔膜用バインダー組成物。 - 前記ポリカルボン酸のガラス転移温度が30℃未満である、請求項1~3のいずれか1項に記載の二次電池多孔膜用バインダー組成物。
- 非導電性粒子、ポリカルボン酸及び水を含む二次電池多孔膜用スラリーであって、
前記ポリカルボン酸は、カルボン酸基含有単量体単位を20質量%以上50質量%以下含み、
前記ポリカルボン酸は、pHが6.5以下で非水溶性、pHが8以上で水溶性であり、
前記二次電池多孔膜用スラリーのpHが7.0超過である、二次電池多孔膜用スラリー。 - 請求項5に記載の二次電池多孔膜用スラリーの層を形成し、前記層を乾燥させてなる、二次電池用多孔膜。
- 請求項6に記載の二次電池用多孔膜を備える二次電池。
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Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006012562A (ja) * | 2004-06-24 | 2006-01-12 | Nitto Denko Corp | 電池用正極/反応性ポリマー担持多孔質フィルム/負極積層体 |
US20060134526A1 (en) * | 2004-11-17 | 2006-06-22 | Han Won C | Lithium ion secondary battery |
WO2009096451A1 (ja) * | 2008-01-29 | 2009-08-06 | Hitachi Maxell, Ltd. | 絶縁層形成用スラリー、電気化学素子用セパレータおよびその製造方法、並びに電気化学素子 |
JP2009193761A (ja) * | 2008-02-13 | 2009-08-27 | Nitto Denko Corp | 電池用セパレータのための反応性ポリマー担持多孔質フィルムとそれより得られる電極/セパレータ接合体。 |
JP2009302009A (ja) * | 2008-06-17 | 2009-12-24 | Sanyo Electric Co Ltd | 非水電解質二次電池及びその製造方法 |
WO2012115252A1 (ja) * | 2011-02-25 | 2012-08-30 | 日本ゼオン株式会社 | 二次電池用多孔膜、二次電池多孔膜用スラリー及び二次電池 |
JP2013122009A (ja) * | 2011-12-12 | 2013-06-20 | Murata Mfg Co Ltd | フッ素樹脂系接着剤、それを用いた蓄電デバイス用のセパレータ、絶縁性接着層、および蓄電デバイス |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4483783B2 (ja) * | 2003-08-04 | 2010-06-16 | 日本ゼオン株式会社 | 電気二重層キャパシタ電極用バインダー |
JP4483784B2 (ja) * | 2003-10-24 | 2010-06-16 | 日本ゼオン株式会社 | 電気二重層キャパシタ電極用バインダー |
JP5370356B2 (ja) | 2008-03-31 | 2013-12-18 | 日本ゼオン株式会社 | 多孔膜および二次電池電極 |
JP5188338B2 (ja) * | 2008-09-16 | 2013-04-24 | 株式会社日立製作所 | テレビジョン受像機 |
EP2372811B1 (en) * | 2008-12-26 | 2015-02-25 | Zeon Corporation | Separator for lithium ion secondary battery, and lithium ion secondary battery |
EP2634839B1 (en) * | 2010-10-28 | 2018-02-21 | Zeon Corporation | Secondary battery porous membrane, slurry for secondary battery porous membrane, and secondary battery |
US9203091B2 (en) * | 2011-02-14 | 2015-12-01 | Zeon Corporation | Slurry for secondary battery negative electrodes, secondary battery negative electrode and manufacturing method thereof, and secondary battery |
WO2013005796A1 (ja) * | 2011-07-06 | 2013-01-10 | 日本ゼオン株式会社 | 二次電池用多孔膜、二次電池用セパレーター及び二次電池 |
KR101819067B1 (ko) * | 2011-12-27 | 2018-01-16 | 제온 코포레이션 | 이차 전지용 정극 및 그 제조 방법, 슬러리 조성물, 그리고 이차 전지 |
WO2013125645A1 (ja) * | 2012-02-23 | 2013-08-29 | 日本ゼオン株式会社 | 二次電池用多孔膜、二次電池用電極、二次電池用セパレーター及び二次電池 |
-
2015
- 2015-02-03 US US15/116,634 patent/US10256446B2/en active Active
- 2015-02-03 CN CN201580006890.XA patent/CN105960721B/zh active Active
- 2015-02-03 WO PCT/JP2015/053011 patent/WO2015129408A1/ja active Application Filing
- 2015-02-03 KR KR1020167021341A patent/KR102294239B1/ko active IP Right Grant
- 2015-02-03 JP JP2016505122A patent/JP6451732B2/ja active Active
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006012562A (ja) * | 2004-06-24 | 2006-01-12 | Nitto Denko Corp | 電池用正極/反応性ポリマー担持多孔質フィルム/負極積層体 |
US20060134526A1 (en) * | 2004-11-17 | 2006-06-22 | Han Won C | Lithium ion secondary battery |
WO2009096451A1 (ja) * | 2008-01-29 | 2009-08-06 | Hitachi Maxell, Ltd. | 絶縁層形成用スラリー、電気化学素子用セパレータおよびその製造方法、並びに電気化学素子 |
JP2009193761A (ja) * | 2008-02-13 | 2009-08-27 | Nitto Denko Corp | 電池用セパレータのための反応性ポリマー担持多孔質フィルムとそれより得られる電極/セパレータ接合体。 |
JP2009302009A (ja) * | 2008-06-17 | 2009-12-24 | Sanyo Electric Co Ltd | 非水電解質二次電池及びその製造方法 |
WO2012115252A1 (ja) * | 2011-02-25 | 2012-08-30 | 日本ゼオン株式会社 | 二次電池用多孔膜、二次電池多孔膜用スラリー及び二次電池 |
JP2013122009A (ja) * | 2011-12-12 | 2013-06-20 | Murata Mfg Co Ltd | フッ素樹脂系接着剤、それを用いた蓄電デバイス用のセパレータ、絶縁性接着層、および蓄電デバイス |
Cited By (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2015185515A (ja) * | 2014-03-26 | 2015-10-22 | 日本ゼオン株式会社 | 二次電池多孔膜用組成物、二次電池用多孔膜及び二次電池 |
JP2015185530A (ja) * | 2014-03-26 | 2015-10-22 | 日本ゼオン株式会社 | 二次電池多孔膜用バインダー、二次電池多孔膜用スラリー組成物、二次電池用多孔膜及び二次電池 |
CN108140838A (zh) * | 2015-09-30 | 2018-06-08 | 日本瑞翁株式会社 | 非水系二次电池电极用粘结剂组合物、非水系二次电池电极用浆料组合物、非水系二次电池用电极以及非水系二次电池 |
CN108140838B (zh) * | 2015-09-30 | 2021-07-23 | 日本瑞翁株式会社 | 非水系二次电池电极用粘结剂组合物、浆料组合物、电极以及非水系二次电池 |
JP2017103056A (ja) * | 2015-11-30 | 2017-06-08 | 日本ゼオン株式会社 | 非水系二次電池機能層用組成物、非水系二次電池機能層用組成物の製造方法、非水系二次電池用機能層及び非水系二次電池 |
JP7088623B2 (ja) | 2016-01-25 | 2022-06-21 | 日本ゼオン株式会社 | 非水系二次電池機能層用スラリー組成物、非水系二次電池用機能層および非水系二次電池 |
JP2017134915A (ja) * | 2016-01-25 | 2017-08-03 | 日本ゼオン株式会社 | 非水系二次電池機能層用スラリー組成物、非水系二次電池用機能層および非水系二次電池 |
KR20170112248A (ko) * | 2016-03-31 | 2017-10-12 | 주식회사 엘지화학 | 세퍼레이터의 제조방법 및 이에 의해 제조된 세퍼레이터 |
KR102178154B1 (ko) * | 2016-03-31 | 2020-11-12 | 주식회사 엘지화학 | 세퍼레이터의 제조방법 및 이에 의해 제조된 세퍼레이터 |
WO2018168657A1 (ja) | 2017-03-13 | 2018-09-20 | 日本ゼオン株式会社 | 非水系二次電池機能層用スラリー組成物、非水系二次電池用機能層および非水系二次電池 |
US11394029B2 (en) | 2017-03-13 | 2022-07-19 | Zeon Corporation | Slurry composition for non-aqueous secondary battery functional layers, non-aqueous secondary battery functional layer, and non-aqueous secondary battery |
JP2018156926A (ja) * | 2017-03-17 | 2018-10-04 | 株式会社東芝 | 二次電池、電池パック及び車両 |
JP2018181833A (ja) * | 2017-04-14 | 2018-11-15 | 住友化学株式会社 | 非水電解液二次電池用塗料 |
JP7220023B2 (ja) | 2017-04-14 | 2023-02-09 | 住友化学株式会社 | 非水電解液二次電池用塗料 |
KR20220041827A (ko) | 2019-07-31 | 2022-04-01 | 니폰 제온 가부시키가이샤 | 비수계 이차 전지 내열층용 바인더 조성물, 비수계 이차 전지 내열층용 슬러리 조성물, 비수계 이차 전지용 내열층, 및 비수계 이차 전지 |
KR20220069921A (ko) | 2019-09-27 | 2022-05-27 | 니폰 제온 가부시키가이샤 | 비수계 이차 전지 내열층용 슬러리 조성물, 비수계 이차 전지용 내열층, 및 비수계 이차 전지 |
WO2023053910A1 (ja) | 2021-09-29 | 2023-04-06 | 日本ゼオン株式会社 | 非水系二次電池機能層用組成物、非水系二次電池用機能層、非水系二次電池用セパレータ及び非水系二次電池 |
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CN105960721B (zh) | 2018-09-25 |
KR20160125364A (ko) | 2016-10-31 |
US20160359156A1 (en) | 2016-12-08 |
KR102294239B1 (ko) | 2021-08-25 |
US10256446B2 (en) | 2019-04-09 |
JP6451732B2 (ja) | 2019-01-16 |
JPWO2015129408A1 (ja) | 2017-03-30 |
CN105960721A (zh) | 2016-09-21 |
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