WO2015159966A1 - 電極の製造方法 - Google Patents
電極の製造方法 Download PDFInfo
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- WO2015159966A1 WO2015159966A1 PCT/JP2015/061782 JP2015061782W WO2015159966A1 WO 2015159966 A1 WO2015159966 A1 WO 2015159966A1 JP 2015061782 W JP2015061782 W JP 2015061782W WO 2015159966 A1 WO2015159966 A1 WO 2015159966A1
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- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
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- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/04—Processes of manufacture in general
- H01M4/0402—Methods of deposition of the material
- H01M4/0404—Methods of deposition of the material by coating on electrode collectors
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- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- 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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- H01M4/04—Processes of manufacture in general
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- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/04—Processes of manufacture in general
- H01M4/0471—Processes of manufacture in general involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
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- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
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- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
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- H01M4/00—Electrodes
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- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/134—Electrodes based on metals, Si or alloys
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- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
- H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
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- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
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- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
- H01M4/1393—Processes of manufacture of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
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- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
- H01M4/1395—Processes of manufacture of electrodes based on metals, Si or alloys
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- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
- H01M4/386—Silicon or alloys based on silicon
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- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
- H01M4/387—Tin or alloys based on tin
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- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
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- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/621—Binders
- H01M4/622—Binders being polymers
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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
- Y02E60/10—Energy storage using batteries
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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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Definitions
- the present invention relates to a method for producing an electrode of an electrochemical element such as a lithium ion secondary battery.
- the present invention relates to a method for producing an electrode using a binder made of polyamic acid.
- lithium ion secondary batteries Since lithium ion secondary batteries have high energy density and high capacity, they are widely used as driving power sources for mobile information terminals. In recent years, use in industrial applications such as mounting on electric / hybrid vehicles that require large capacity is becoming widespread, and studies for higher capacity and higher performance are being made.
- One of the attempts is to increase the charge / discharge capacity by using silicon or tin having a large amount of lithium occlusion per unit volume or an alloy containing these as the negative electrode active material.
- Patent Document 1 describes that, in a lithium secondary battery, when a polyimide resin is used as a binder for a negative electrode, the battery capacity is hardly reduced even if the charge / discharge cycle is repeated, and the cycle life is prolonged.
- the electrode is manufactured by heat treatment at 350 ° C. for 2 hours.
- Patent Document 2 describes a binder resin composition for an electrode comprising a specific polyamic acid and a solvent, which has a low degree of swelling with respect to an electrolytic solution and has excellent toughness (large breaking elongation and breaking energy). Further, it is described that when an electrode is produced, a heat treatment at a relatively high temperature is necessary so that the imidization reaction proceeds sufficiently.
- Patent Document 3 describes a resin composition for an electrode of a lithium ion secondary battery containing a polyimide resin having a carboxyl group and an epoxy resin.
- Non-Patent Document 1 shows that the smaller the degree of swelling of the binder resin for electrodes with respect to the electrolytic solution, the higher the discharge capacity retention rate associated with the charge / discharge cycle, which is preferable.
- an object of the present invention is a high performance capable of maintaining a low degree of swelling even in a battery environment and maintaining excellent adhesion and toughness by heat treatment at a relatively low temperature of 200 ° C. or less and for a relatively short time. It is to propose a method for manufacturing an electrode, which can easily obtain an electrode for a lithium secondary battery.
- the inventors of the present application have used an electrode mixture composition containing a polyamic acid having a specific chemical structure, so that the electrode can be heated at a relatively low temperature of 200 ° C. or lower and at a relatively short time. It is found that a high-performance electrode for a lithium secondary battery that has a low degree of swelling even in a battery environment and can maintain excellent adhesion and toughness can be easily obtained. It came to.
- An electrode mixture layer is formed on the surface of the current collector with an electrode mixture composition containing at least an electrode active material and a polyamide acid having a repeating unit represented by the following chemical formula (1), and then heat treatment And removing the solvent, and performing an imidization reaction of the polyamic acid.
- A consists of one or more tetravalent groups selected from the group consisting of the following chemical formula (2), the following chemical formula (3), and the following chemical formula (4)
- B is the following chemical formula: (5), one or more divalent groups selected from the group consisting of the following chemical formula (6), the following chemical formula (7), the following chemical formula (8), and a divalent saturated hydrocarbon group having 4 to 10 carbon atoms.
- X is a direct bond, oxygen atom, sulfur atom, methylene group, carbonyl group, sulfoxyl group, sulfone group, 1,1′-ethylidene group, 1,2-ethylidene group, 2,2′- Isopropylidene group, 2,2′-hexafluoroisopropylidene group, cyclohexylidene group, phenylene group, 1,3-phenylenedimethylene group, 1,4-phenylenedimethylene group, 1,3-phenylenediethylidene group, 1,4-phenylenediethylidene group, 1,3-phenylenedipropylidene group, 1,4-phenylenedipropylidene group, 1,3-phenylenedioxy group, 1,4-phenylenedioxy group, biphenylenedioxy
- Y is a direct bond, oxygen atom, sulfur atom, methylene group, carbonyl group, sulfoxyl group, sulfone group, 1,1′-ethylidene group, 1,2-ethylidene group, 2,2′- Isopropylidene group, 2,2′-hexafluoroisopropylidene group, cyclohexylidene group, phenylene group, 1,3-phenylenedimethylene group, 1,4-phenylenedimethylene group, 1,3-phenylenediethylidene group, 1,4-phenylenediethylidene group, 1,3-phenylenedipropylidene group, 1,4-phenylenedipropylidene group, 1,3-phenylenedioxy group, 1,4-phenylenedioxy group, biphenylenedioxy Group, methylene diphenoxy group, ethylidene diphenoxy group, propylidene di
- Item 2 The method for producing an electrode according to Item 1, wherein the electrode mixture composition further contains a crosslinking agent having an epoxy group or an oxazoline group. 3. Item 3. The method for producing an electrode according to Item 1 or 2, wherein the electrode mixture composition further contains a pyridine compound. 4). Item 4. The method for producing an electrode according to any one of Items 1 to 3, wherein the electrode active material is carbon powder, silicon powder, tin powder, or an alloy powder containing silicon or tin. 5. Item 5. The method for producing an electrode according to any one of Items 1 to 4, wherein the electrode active material is a lithium transition metal oxide. 6). Item 6. The method for producing an electrode according to any one of Items 1 to 5, wherein an electrode for a lithium ion secondary battery is obtained.
- a heat treatment at a relatively low temperature of 200 ° C. or less and for a relatively short time a high degree of swelling and low adhesion can be maintained even in a battery environment using polyimide as a binder.
- An electrode for a lithium secondary battery can be easily obtained.
- the electrode production method of the present invention can particularly suitably produce electrodes (negative electrode and positive electrode) of lithium secondary batteries.
- electrodes negative electrode and positive electrode
- the electrode production method of the present invention demonstrates based on the manufacturing method of the electrode for lithium secondary batteries especially.
- the current collector is preferably a conductive metal foil usually used in batteries.
- the conductive metal foil include a metal foil having conductivity such as copper, aluminum, nickel, stainless steel (iron), titanium, and cobalt, or an alloy foil made of a combination thereof.
- a foil made of copper or a copper alloy having a thickness of about 5 to 100 ⁇ m is used as the negative electrode current collector, and an aluminum foil having a thickness of about 5 to 100 ⁇ m is used as the positive electrode current collector. It is suitable because it is easy to process, inexpensive, and easily improves the performance of the electrode.
- the current collector has a surface roughness controlled as required, and may have a shape other than foil, such as a flat plate shape, a mesh shape, a net shape, a lath shape, a punching metal shape, and an embossed shape.
- the electrode mixture composition (electrode mixture paste) used in the present invention contains at least an electrode active material, a binder composed of a polyamic acid having a specific repeating unit, and a solvent.
- the electrode active material of the electrode mixture composition used in the present invention is not limited as long as it is usually used in a battery.
- any substance that can electrochemically insert and desorb lithium can be used.
- carbon powder such as graphite, cokes, carbon black, pyrolytic carbon, silicon powder, tin powder, or silicon Or the alloy powder containing tin can be mentioned.
- the alloy powder is preferably an intermetallic compound of silicon or tin and a metal element, and the metal element is preferably a transition metal such as nickel, titanium, iron, cobalt, copper, zircon, or manganese.
- the metal element is preferably a transition metal such as nickel, titanium, iron, cobalt, copper, zircon, or manganese.
- any material that has lithium element and can electrochemically desorb and insert lithium may be used.
- Preferable examples include lithium transition metal oxides such as Co 0.2 Mn 0.1 O 2 .
- the binder of the electrode mixture composition used in the present invention comprises a polyamic acid having a repeating unit of the chemical formula (1).
- This polyamic acid can be easily prepared by reacting a tetracarboxylic acid component and a diamine component at a low temperature in order to suppress the imidization reaction.
- the tetracarboxylic acid component is a tetracarboxylic acid, that is, a tetracarboxylic acid, its acid dianhydride, its esterified compound, or the like, preferably a dianhydride.
- the tetravalent group represented by A is selected from the group consisting of the chemical formula (2), the chemical formula (3), and the chemical formula (4) described above. One or more types are used.
- Such a tetravalent group is derived from a tetracarboxylic acid.
- the tetracarboxylic acid that is the base of such a tetravalent group is referred to as a “tetracarboxylic acid component”.
- the tetracarboxylic acid component constituting the polyamic acid of the present invention is preferably selected from the group consisting of 4,4′-oxydiphthalic acids, 3,3 ′, 4,4′-biphenyltetracarboxylic acids, and pyromellitic acids.
- Two or more tetracarboxylic acids preferably 3,3 ′, 4,4′-biphenyltetracarboxylic acids or 4,4′-oxydiphthalic acids and 3,3 ′, 4,4′-biphenyltetracarboxylic acids It is a mixture comprising a combination of acids and / or pyromellitic acids.
- the mixture is composed of 10 to 90 mol%, further 20 to 60 mol% of 4,4′-oxydiphthalic acid, and 90 to 10 mol%, further 80 to 40 mol% of 3,3 ′, 4,4′-biphenyltetracarboxylic acid. And / or a mixture composed of a combination with pyromellitic acids.
- the divalent group represented by B As the divalent group represented by B, the chemical formula (5), chemical formula (6), chemical formula (7), chemical formula (8) and One or more selected from the group consisting of divalent saturated hydrocarbon groups having 4 to 10 carbon atoms are used.
- a divalent group is derived from a diamine.
- the diamine that is the source of such a divalent group is referred to as a “diamine component”.
- the diamine component constituting the polyamic acid of the present invention preferably contains one or more diamines selected from aromatic diamines having 1 to 4 aromatic rings and aliphatic diamines having 4 to 10 carbon atoms.
- aromatic diamines having 1 to 4 aromatic rings include p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 2,4-bis ( ⁇ -amino-tert-butyl) toluene, 1 aromatic such as bis-p- (1,1-dimethyl-5-amino-pentyl) benzene, 1-isopropyl-2,4-m-phenylenediamine, m-xylylenediamine, p-xylylenediamine
- An aromatic diamine having a ring 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, 3,3′-diaminodiphenylmethane, 3,3′-dichlorobenzidine, 4,4′-diaminodiphenyl sulfide, 3,3′-diaminodiphenyl sulfone, 1,5-dia
- aromatic diamine which has four aromatic rings
- the aromatic diamine represented by following Chemical formula (8) can be mentioned suitably.
- X is a direct bond, oxygen atom, sulfur atom, methylene group, carbonyl group, sulfoxyl group, sulfone group, 1,1′-ethylidene group, 1,2-ethylidene group, 2, 2'-isopropylidene group, 2,2'-hexafluoroisopropylidene group, cyclohexylidene group, phenylene group, 1,3-phenylenedimethylene group, 1,4-phenylenedimethylene group, 1,3-phenylenediene Ethylidene group, 1,4-phenylenediethylidene group, 1,3-phenylenedipropylidene group, 1,4-phenylenedipropylidene group, 1,3-phenylenedioxy group, 1,4-phenylenedioxy group, Bipheny
- Examples of the aliphatic diamine having 4 to 10 carbon atoms include 1,4-diaminobutane, 1,3-diaminopentane, 1,5-diaminopentane, 1,6-diaminohexane (hexamethylenediamine), 1,7- Preferable examples include diamines such as diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, and 1,10-diaminodecane.
- the diamine component constituting the polyamic acid used in the present invention is 50 to 99 mol%, preferably 70 to 97 mol, of one or more diamines selected from the above aromatic diamines having 1 to 4 aromatic rings. %, More preferably 80 to 95 mol%.
- the diamine component constituting the polyamic acid used in the present invention further contains 1 to 50 mol%, preferably 3 to 30 mol%, more preferably 5 to 20 mol% of a diamine having a polar group.
- the diamine having a polar group an aromatic diamine having a polar group having reactivity with an epoxy resin such as a hydroxyl group or a carboxyl group in the molecule is suitable.
- aromatic diamines having polar groups include diaminophenol compounds such as 2,4-diaminophenol, 3,3′-diamino-4,4′-dihydroxybiphenyl, and 4,4′-diamino.
- Hydroxybiphenyl such as -3,3'-dihydroxybiphenyl, 4,4'-diamino-2,2'-dihydroxybiphenyl, 4,4'-diamino-2,2 ', 5,5'-tetrahydroxybiphenyl
- 3,3′-diamino-4,4′-dihydroxydiphenylmethane 4,4′-diamino-3,3′-dihydroxydiphenylmethane
- 4,4′-diamino-2,2′-dihydroxydiphenylmethane 2,2-bis [3-amino-4-hydroxyphenyl] propane, 2,2-bis [4-amino-3-hydroxyphene] L] propane, 2,2-bis
- benzenecarboxylic acids such as 3,5-diaminobenzoic acid and 2,4-diaminobenzoic acid, 3,3′-diamino-4,4′-dicarboxybiphenyl, 4,4′-diamino-3,3 ′
- Carboxybiphenyl compounds such as dicarboxybiphenyl, 4,4′-diamino-2,2′-dicarboxybiphenyl, 4,4′-diamino-2,2 ′, 5,5′-tetracarboxybiphenyl, 3,3 '-Diamino-4,4'-dicarboxydiphenylmethane, 4,4'-diamino-3,3'-dicarboxydiphenylmethane, 4,4'-diamino-2,2'-dicarboxydiphenylmethane, 2,2-bis [3-amino-4-carboxyphenyl] propane, 2,2-bis [4
- Y is a direct bond, oxygen atom, sulfur atom, methylene group, carbonyl group, sulfoxyl group, sulfone group, 1,1′-ethylidene group, 1,2-ethylidene group, 2,2′- Isopropylidene group, 2,2′-hexafluoroisopropylidene group, cyclohexylidene group, phenylene group, 1,3-phenylenedimethylene group, 1,4-phenylenedimethylene group, 1,3-phenylenediethylidene group, 1,4-phenylenediethylidene group, 1,3-phenylenedipropylidene group, 1,4-phenylenedipropylidene group, 1,3-phenylenedioxy group, 1,4-phenylenedioxy group, biphen
- the diamine component constituting the polyamic acid used in the present invention is, in particular, p-phenylenediamine, 4,4'-diaminodiphenyl ether, 1,3-bis (4-aminophenoxy) benzene, 2,2-bis.
- the molar ratio [tetracarboxylic acid component / diamine component] of the tetracarboxylic acid component and the diamine component constituting the polyamic acid used in the present invention is approximately equimolar, specifically 0.95 to 1.05, preferably 0.97. It is important to set it to ⁇ 1.03. Outside the range of this molar ratio, the molecular weight of the resulting polyimide is low, so that the toughness when used as a binder may be insufficient. Further, the polyamic acid used in the present invention has a high molecular weight having a logarithmic viscosity of 0.2 or more, preferably 0.4 or more, more preferably 0.6 or more measured at a temperature of 30 ° C.
- Polyamic acid can be easily prepared by reacting a diamine component and a tetracarboxylic acid component in a solvent according to a known method. Although it does not limit, normally, it can carry out suitably by adding the tetracarboxylic acid component to the solution which melt
- the reaction temperature is preferably 10 ° C to 100 ° C, more preferably 15 ° C to 80 ° C, and particularly preferably 15 ° C to 50 ° C. When the reaction temperature is lower than 10 ° C., the reaction is slow, which is not preferable. When the reaction temperature is higher than 100 ° C., the viscosity of the solution may be decreased.
- the reaction time is preferably in the range of 0.5 to 72 hours, more preferably 1 to 60 hours, and particularly preferably 1.5 to 48 hours.
- the reaction time is shorter than 0.5 hours, the reaction does not proceed sufficiently, and the viscosity of the synthesized polyamic acid solution may become unstable.
- taking 72 hours or more is not preferable from the viewpoint of productivity.
- the polyamic acid can be dissolved, and a known organic solvent used when preparing a normal polyamic acid can be used.
- a known organic solvent used when preparing a normal polyamic acid can be used.
- N, N-dimethylacetamide, N, N-diethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,3-dimethyl are considered because of the solubility and safety of polyamic acid.
- -2-Imidazolidinone and ⁇ -butyrolactone are preferable, and N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and ⁇ -butyrolactone are particularly preferable.
- the prepared polyamic acid solution is obtained by uniformly dissolving polyamic acid in a solvent.
- This polyamic acid solution has a solid content concentration due to the polyamic acid of more than 5% by mass to 45% by mass, preferably more than 10% by mass to 40% by mass, and more preferably based on the total amount of the solvent and the polyamic acid. It can be suitably used as a solution of more than 15% by mass to 30% by mass. If the solid content concentration due to the polyamic acid is lower than 5% by mass, the viscosity of the solution becomes too low, and if it is higher than 45% by mass, the fluidity of the solution may be lost. The solution viscosity at 30 ° C.
- the solution viscosity is preferably 1000 Pa ⁇ s or less, more preferably 0.5 to 500 Pa ⁇ s, still more preferably 1 to 300 Pa ⁇ s, and particularly preferably 3 to 200 Pa ⁇ s.
- the solution viscosity exceeds 1000 Pa ⁇ s, it becomes difficult to mix the electrode active material powder and uniformly apply on the current collector.
- the solution viscosity is lower than 0.5 Pa ⁇ s, the electrode active material powder is mixed and the current collector. There is a risk that dripping or the like may occur during coating on the top, and the toughness of the polyimide resin after heat drying and imidization may be lowered.
- the polyamic acid is isolated by, for example, a method in which a polyamic acid solution obtained by reacting a diamine component and a tetracarboxylic acid component in a solvent is poured into a poor solvent and precipitated (there is converted into a predetermined solvent).
- the prepared polyamic acid solution may be used without being isolated, or may be used as it is or simply diluted. From the viewpoint of productivity and cost, it is preferable to use the obtained polyamic acid solution as it is without isolation.
- the solvent of the electrode mixture composition (electrode mixture paste) used in the present invention a conventionally known organic solvent capable of dissolving polyamic acid can be suitably used.
- An organic polar solvent having a boiling point of 300 ° C. or less at normal pressure is preferable, and the solvent used in the preparation of polyadic acid can be suitably used.
- a crosslinking agent having an epoxy group or an oxazoline group reduces the adhesive strength between the electrode mixture layer and the current collector when in contact with the electrolytic solution. It is preferable because it can be suppressed.
- An epoxy resin can be mentioned as a crosslinking agent having an epoxy group.
- the crosslinking agent having an oxazoline group include 1,3-phenylenebisoxazoline and oxazoline group-containing resin.
- the addition amount of the crosslinking agent is preferably 0.05 to 5% by mass, more preferably 0.1 to 3% by mass with respect to the polyamic acid.
- a pyridine compound in the electrode mixture composition used in the present invention, further containing a pyridine compound can further reduce the degree of swelling of the resulting polyimide binder with respect to the electrolyte, and can increase the elongation at break and the energy at break. Further, it is preferable because the heat treatment time for obtaining the electrode can be shortened and the heat treatment temperature can be further reduced.
- the pyridine compound is a compound having a pyridine skeleton in its chemical structure.
- the addition amount of the pyridine compound is not limited, but is preferably 0.05 to 2.0 molar equivalents, more preferably 0.8, relative to the amic acid structure of the polyamic acid (per mole of the amic acid structure). 1 to 1.0 molar equivalent.
- the addition amount is outside this range, the swelling degree of the resin with respect to the electrolytic solution is made smaller, the breaking elongation and breaking energy of the resulting polyimide binder are made larger, and further the heat treatment temperature for obtaining the electrode is kept lower. It may be difficult to obtain the effect of adding a pyridine compound.
- additives such as surfactants, viscosity modifiers (thickeners), conductive assistants (conductive agents), etc., which are contained in normal electrode mixture compositions are suitable. It can contain.
- the binder component other than the polyamic acid is preferably present in a proportion of less than 50% by mass, preferably less than 30% by mass, more preferably less than 10% by mass, based on the total amount of the binder component containing the polyamic acid.
- the electrode mixture composition of the present invention is preferably obtained in a slurry state by adding an electrode active material and other components as required to the binder resin composition for an electrode containing the polyamic acid and kneading the mixture sufficiently. It is done.
- the amount of the electrode active material in the electrode mixture composition is not particularly limited, but is usually 0.1 to 1000 times, preferably 1 to 1000 times on a mass basis with respect to the solid content mass caused by polyamic acid. More preferably, it is 5 to 1000 times, and further preferably 10 to 1000 times. If the amount of the electrode active material is too small, an inactive portion increases in the electrode mixture layer formed on the current collector, and the function as an electrode may be insufficient.
- each component is preferably mixed so that the solid content attributable to the polyamic acid is 1 to 15% by mass in the total solid content. Outside this range, the electrode performance may deteriorate.
- the current collector is coated and casted on the surface of the current collector by coating and casting an electrode mixture composition containing at least an electrode active material, a polyamide acid binder and a solvent.
- an electrode mixture composition containing at least an electrode active material, a polyamide acid binder and a solvent.
- the electrode mixture layer is usually adjusted to a thickness of about 10 to 300 ⁇ m after drying.
- the electrode mixture layer is formed on one side or both sides of the current collector.
- the laminate in which the electrode mixture layer is formed on the surface of the current collector is heat-treated to remove the solvent and convert the polyamic acid amic acid structure into an imide structure.
- This heat treatment step is preferably performed in a temperature range of 80 ° C. to 200 ° C., preferably 90 ° C. to 180 ° C., more preferably 100 ° C. to 150 ° C.
- heat processing temperature is 80 degrees C or less, imidation reaction may not fully advance or the physical property of an electrode molded object may fall.
- it exceeds 200 degreeC there exists a possibility that a collector may deteriorate.
- the heat treatment may be performed by a method in which the temperature is raised stepwise in multiple stages in order to prevent foaming and powdering.
- the heat treatment time is preferably in the range of 10 minutes to 48 hours. 48 hours or longer is not preferable from the viewpoint of productivity, and if it is shorter than 10 minutes, imidation reaction or solvent removal may be insufficient. During this time, most of the solvent is removed and the polyamic acid is substantially converted to polyimide by the imidization reaction.
- the heat treatment can be suitably performed under reduced pressure conditions or under an inert gas flow condition.
- substantially becoming polyimide means that the amic acid structure may remain in the polyimide, and is 70% or more, preferably 80% or more, more preferably 90% or more of the amic acid structure. May be imidized.
- the binder composed of a polyamic acid composed of a repeating unit composed of a specific tetracarboxylic acid component and a diamine component of the present invention has a low degree of swelling even in a battery environment by such low temperature heat treatment (dimethyl carbonate).
- the mass increase rate due to swelling when immersed in a glass substrate at 25 ° C. for 24 hours is preferably 2% by mass or less, more preferably 1% by mass or less) and excellent adhesion (90 ° peel strength with a current collector is 0.00).
- peeling is less than 5%, and 2 at 25 ° C.
- the exfoliation after being immersed in dimethyl carbonate for 4 hours is less than 5%) and can exhibit excellent characteristics required as a binder for high-performance batteries that can maintain toughness. Details of the 90 ° peel strength measurement and the adhesion test by the cross-cut method will be described later.
- the electrode obtained by the method for producing an electrode of the present invention can suitably produce a battery according to a known method.
- the obtained positive electrode and negative electrode are wound into a cylindrical shape, for example, while sandwiching a separator such as a polyolefin porous body in accordance with a normal method, and this cylindrical electrode body is
- the battery can be suitably obtained by inserting the electrode body and the nonaqueous electrolytic solution into the exterior body while remaining in the shape or being crushed into a flat shape.
- binder binder resin composition
- a binder resin composition comprising a polyamic acid having a repeating unit represented by the chemical formula (1), which is a feature of the present invention
- a binder resin composition comprising a polyamic acid having a repeating unit represented by the chemical formula (1), which is a feature of the present invention
- ⁇ Solution stability> The sample solution was stored in an atmosphere adjusted to a temperature of 25 ° C., and a change in solution viscosity after 1 month was within ⁇ 10%, and a sample with a change exceeding ⁇ 10% was rated as x.
- the change in solution viscosity is defined as ⁇ (solution viscosity after storage for one month ⁇ solution viscosity before storage) / solution viscosity before storage ⁇ ⁇ 100.
- ⁇ DMC swelling test> A sample obtained by cutting an electrode composed of a copper foil and an electrode mixture layer into a 5 cm square is used as a sample, and the mass of the electrode mixture layer alone is determined by subtracting the mass of the copper foil by calculation.
- the following dimethyl carbonate (DMC) The degree of swelling S of the electrode mixture layer was measured by a swelling test with a solution. That is, the mass of the electrode mixture layer after being vacuum-dried at 25 ° C. for 24 hours is defined as the dry mass (W d ), and the mass of the electrode mixture layer after being immersed in a dimethyl carbonate solution at 25 ° C. for 24 hours is the swollen mass (W w ) And the degree of swelling S was calculated by the following formula.
- S [mass%] ⁇ (W w ⁇ W d ) / W w ⁇ ⁇ 100
- ⁇ Adhesion test (cross-cut method)> The adhesion test was conducted according to JIS K 5600-5-6. The evaluation was visually indicated as classification 0 to classification 5 (the smaller the number, the stronger the adhesion) based on the evaluation standard (3). The adhesion test was performed on samples before and after the swelling test with a dimethyl carbonate solution.
- the 90 ° peel strength test was measured using a universal testing machine (RTC-1225A manufactured by Orientec Co., Ltd.) in accordance with IPC-TM650.
- ODPA 4,4′-oxydiphthalic dianhydride s-BPDA: 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride
- PPD p-phenylenediamine
- ODA 4,4′-diaminodiphenyl ether
- HMD Hexamethylenediamine 3,5-DABA: 3,5-diaminobenzoic acid
- MBAA 4,4′-diamino-3,3′-dicarboxydiphenylmethane
- 1,3-PBO 1,3-phenylenebisoxazoline
- Example 1 400 g of NMP was added as a solvent to a glass reaction vessel having an internal volume of 500 mL equipped with a stirrer and a nitrogen gas introduction / discharge tube, and 36.81 g (0.184 mol) of ODA and 3.11 g (0.11 mol) were added. 020 mol) 3,5-DABA and 60.09 g (0.204 mol) s-BPDA were added and stirred at 50 ° C. for 10 hours to obtain a solid content concentration of 18.2% by mass and a solution viscosity of 5. A polyamic acid solution having 3 Pa ⁇ s and a logarithmic viscosity of 0.62 was obtained.
- a binder resin composition for electrodes 1% by mass of an epoxy resin was added to the obtained polyamic acid solution to obtain a binder resin composition for electrodes.
- the copper foil coated with the electrode binder resin composition was fixed on a substrate, defoamed and pre-dried at 25 ° C. under reduced pressure for 30 minutes, and then placed in a hot air drier under normal pressure and nitrogen gas atmosphere. And a heat treatment at 120 ° C. for 1 hour to form a binder resin film having a thickness of 25 ⁇ m.
- a DMC swelling test was performed using a binder resin film formed on the copper foil as a sample. Further, an adhesion test and a 90 ° peel strength measurement were performed on the samples before and after the swelling test with a dimethyl carbonate solution. These results are shown in Table 1.
- the electrode binder composition (electrode) was prepared by kneading 4.4 g of the electrode binder resin composition (solid content after imidization 0.8 g) and 9.2 g of 325 mesh pass silicon powder so as to be ground in a mortar.
- a mixture paste was prepared. The obtained paste could be thinly spread on the copper foil with a glass rod.
- the copper foil coated with the paste was fixed on the substrate, defoamed and pre-dried at 25 ° C. under reduced pressure for 30 minutes, and then placed in a hot air drier under normal pressure and nitrogen gas atmosphere at 120 ° C. for 1 hour. Heat treatment was performed to produce an electrode with an electrode mixture layer thickness of 100 ⁇ m.
- a DMC swelling test was performed using the obtained electrode as a sample. Moreover, the adhesion test was done about the sample before and behind the swelling test in a dimethyl carbonate solution.
- Example 2 Various tests were conducted in the same manner as in Example 1 except that 1% by mass of 1,3-PBO was added to the electrode binder resin composition instead of the epoxy resin. These results are shown in Table 1.
- Example 3 The test was performed in the same manner as in Example 1 except that nothing was added to the electrode binder resin composition of Example 1. These results are shown in Table 1.
- Example 4 To a 500 mL glass reaction vessel equipped with a stirrer and a nitrogen gas inlet / outlet pipe, 400 g of NMP was added as a solvent, and 35.83 g (0.179 mol) of ODA and 5.69 g of MBAA were added thereto. (0.020 mol) and 58.48 g (0.199 mol) of s-BPDA were added and stirred at 50 ° C. for 10 hours to obtain a solid content concentration of 18.1% by mass and a solution viscosity of 5.1 Pa ⁇ s. A polyamic acid solution having a logarithmic viscosity of 0.65 was obtained.
- a binder resin composition for electrodes 1% by mass of an epoxy resin was added to the obtained polyamic acid solution to obtain a binder resin composition for electrodes.
- the copper foil coated with the electrode binder resin composition was fixed on a substrate, defoamed and pre-dried at 25 ° C. under reduced pressure for 30 minutes, and then placed in a hot air drier under normal pressure and nitrogen gas atmosphere. And a heat treatment at 120 ° C. for 1 hour to form a binder resin film having a thickness of 25 ⁇ m.
- a DMC swelling test was performed using a binder resin film formed on the copper foil as a sample. Further, an adhesion test and a 90 ° peel strength measurement were performed on the samples before and after the swelling test with a dimethyl carbonate solution. These results are shown in Table 2.
- the electrode binder composition (electrode) was prepared by kneading 4.4 g of the electrode binder resin composition (solid content after imidization 0.8 g) and 9.2 g of 325 mesh pass silicon powder so as to be ground in a mortar.
- a mixture paste was prepared. The obtained paste could be thinly spread on the copper foil with a glass rod.
- the copper foil coated with the paste was fixed on the substrate, defoamed and pre-dried at 25 ° C. under reduced pressure for 30 minutes, and then placed in a hot air drier under normal pressure and nitrogen gas atmosphere at 120 ° C. for 1 hour. Heat treatment was performed to produce an electrode with an electrode mixture layer thickness of 100 ⁇ m.
- a DMC swelling test was performed using the obtained electrode as a sample. Moreover, the adhesion test was done about the sample before and behind the swelling test in a dimethyl carbonate solution.
- Example 5 Various tests were conducted in the same manner as in Example 4 except that 1% by mass of 1,3-PBO was added to the electrode binder resin composition instead of the epoxy resin. These results are shown in Table 1.
- Example 6 The test was conducted in the same manner as in Example 4 except that nothing was added to the electrode binder resin composition of Example 4. These results are shown in Table 1.
- Example 7 To a 500 mL glass reaction vessel equipped with a stirrer and nitrogen gas inlet / outlet pipe, 400 g of NMP was added as a solvent, and 13.20 g (0.066 mol) of ODA and 3,5-DABA were added thereto. 3.34 g (0.022 mol) of HMD and 15.32 g (0.132 mol) of HMD and 68.14 g (0.220 mol) of ODPA were added and stirred at 50 ° C. for 10 hours to obtain a solid content. A polyamic acid solution having a concentration of 17.9% by mass, a solution viscosity of 5.0 Pa ⁇ s, and a logarithmic viscosity of 0.71 was obtained.
- a binder resin composition for electrodes 1% by mass of an epoxy resin was added to the obtained polyamic acid solution to obtain a binder resin composition for electrodes.
- the copper foil coated with the electrode binder resin composition was fixed on a substrate, defoamed and pre-dried at 25 ° C. under reduced pressure for 30 minutes, and then placed in a hot air drier under normal pressure and nitrogen gas atmosphere. And a heat treatment at 120 ° C. for 1 hour to form a binder resin film having a thickness of 25 ⁇ m.
- a DMC swelling test was performed using a binder resin film formed on the copper foil as a sample. Further, an adhesion test and a 90 ° peel strength measurement were performed on the samples before and after the swelling test with a dimethyl carbonate solution. These results are shown in Table 2.
- the electrode binder composition (electrode) was prepared by kneading 4.5 g of the binder resin composition for an electrode (solid content mass after imidization 0.8 g) and 9.2 g of silicon powder of 325 mesh pass so as to be ground in a mortar.
- a mixture paste was prepared. The obtained paste could be thinly spread on the copper foil with a glass rod.
- the copper foil coated with the paste was fixed on the substrate, defoamed and pre-dried at 25 ° C. under reduced pressure for 30 minutes, and then placed in a hot air drier under normal pressure and nitrogen gas atmosphere at 120 ° C. for 1 hour. Heat treatment was performed to produce an electrode with an electrode mixture layer thickness of 100 ⁇ m.
- a DMC swelling test was performed using the obtained electrode as a sample. Moreover, the adhesion test was done about the sample before and behind the swelling test in a dimethyl carbonate solution.
- Example 8 Various tests were conducted in the same manner as in Example 7 except that 1% by mass of 1,3-PBO was added to the electrode binder resin composition instead of the epoxy resin.
- Example 9 The test was performed in the same manner as in Example 7 except that nothing was added to the electrode binder resin composition of Example 7. These results are shown in Table 2.
- Example 10 400 g of NMP was added as a solvent to a glass reaction vessel having an internal volume of 500 mL equipped with a stirrer and a nitrogen gas introduction / discharge tube, and 12.82 g (0.064 mol) of ODA and 6.11 g of MBAA were added thereto. (0.021 mol) and 14.88 g (0.128 mol) of HMD and 66.19 g (0.213 mol) of ODPA were added and stirred at 50 ° C. for 10 hours to obtain a solid concentration of 18.0. A polyamic acid solution having a mass%, a solution viscosity of 4.9 Pa ⁇ s, and a logarithmic viscosity of 0.73 was obtained.
- a binder resin composition for electrodes 1% by mass of an epoxy resin was added to the obtained polyamic acid solution to obtain a binder resin composition for electrodes.
- the copper foil coated with the electrode binder resin composition was fixed on a substrate, defoamed and pre-dried at 25 ° C. under reduced pressure for 30 minutes, and then placed in a hot air drier under normal pressure and nitrogen gas atmosphere. And a heat treatment at 120 ° C. for 1 hour to form a binder resin film having a thickness of 25 ⁇ m.
- a DMC swelling test was performed using a binder resin film formed on the copper foil as a sample. Further, an adhesion test and a 90 ° peel strength measurement were performed on the samples before and after the swelling test with a dimethyl carbonate solution. These results are shown in Table 2.
- the electrode binder composition (electrode) was prepared by kneading 4.5 g of the binder resin composition for an electrode (solid content mass after imidization 0.8 g) and 9.2 g of silicon powder of 325 mesh pass so as to be ground in a mortar.
- a mixture paste was prepared. The obtained paste could be thinly spread on the copper foil with a glass rod.
- the copper foil coated with the paste was fixed on the substrate, defoamed and pre-dried at 25 ° C. under reduced pressure for 30 minutes, and then placed in a hot air drier under normal pressure and nitrogen gas atmosphere at 120 ° C. for 1 hour. Heat treatment was performed to produce an electrode with an electrode mixture layer thickness of 100 ⁇ m.
- a DMC swelling test was performed using the obtained electrode as a sample. Moreover, the adhesion test was done about the sample before and behind the swelling test in a dimethyl carbonate solution.
- Example 11 Various tests were conducted in the same manner as in Example 10 except that 1% by mass of 1,3-PBO was added to the electrode binder resin composition instead of the epoxy resin. These results are shown in Table 2.
- Example 12 The test was performed in the same manner as in Example 10 except that nothing was added to the electrode binder resin composition of Example 10. These results are shown in Table 2.
- Example 13 400 g of NMP was added as a solvent to a glass reaction vessel having an internal volume of 500 mL equipped with a stirrer and a nitrogen gas introduction / discharge tube, and 4.51 g (0.042 mol) of PPD and 29.25 g of ODA were added thereto. (0.146 mol) and 3.18 g (0.021 mol) of 3,5-DABA, 30.70 g (0.104 mol) of s-BPDA and 32.37 g (0.104 mol) of ODPA And stirred at 50 ° C.
- a polyamic acid solution having a solid content concentration of 18.2% by mass, a solution viscosity of 5.3 Pa ⁇ s, and a logarithmic viscosity of 0.68.
- 1% by mass of an epoxy resin was added to the obtained polyamic acid solution to obtain a binder resin composition for electrodes.
- the copper foil coated with the electrode binder resin composition was fixed on a substrate, defoamed and pre-dried at 25 ° C. under reduced pressure for 30 minutes, and then placed in a hot air drier under normal pressure and nitrogen gas atmosphere. And a heat treatment at 120 ° C. for 1 hour to form a binder resin film having a thickness of 25 ⁇ m.
- a DMC swelling test was performed using a binder resin film formed on the copper foil as a sample. Further, an adhesion test and a 90 ° peel strength measurement were performed on the samples before and after the swelling test with a dimethyl carbonate solution. These results are shown in Table 3.
- the electrode binder composition (electrode) was prepared by kneading 4.5 g of the binder resin composition for an electrode (solid content mass after imidization 0.8 g) and 9.2 g of silicon powder of 325 mesh pass so as to be ground in a mortar.
- a mixture paste was prepared. The obtained paste could be thinly spread on the copper foil with a glass rod.
- the copper foil coated with the paste was fixed on the substrate, defoamed and pre-dried at 25 ° C. under reduced pressure for 30 minutes, and then placed in a hot air drier under normal pressure and nitrogen gas atmosphere at 120 ° C. for 1 hour. Heat treatment was performed to produce an electrode with an electrode mixture layer thickness of 100 ⁇ m.
- a DMC swelling test was performed using the obtained electrode as a sample. Moreover, the adhesion test was done about the sample before and behind the swelling test in a dimethyl carbonate solution.
- Example 14 Various tests were conducted in the same manner as in Example 13 except that 1% by mass of 1,3-PBO was added to the electrode binder resin composition instead of the epoxy resin. These results are shown in Table 3.
- Example 15 The test was performed in the same manner as in Example 13 except that nothing was added to the electrode binder resin composition of Example 13. These results are shown in Table 3.
- Example 16 400 g of NMP was added as a solvent to a glass reaction vessel having an internal volume of 500 mL equipped with a stirrer and a nitrogen gas introduction / discharge tube, and 4.51 g (0.042 mol) of PPD and 29.25 g of ODA were added thereto. (0.146 mol) and 3.18 g (0.021 mol) of 3,5-DABA, 30.70 g (0.104 mol) of s-BPDA and 32.37 g (0.104 mol) of ODPA And stirred at 50 ° C.
- a polyamic acid solution having a solid content concentration of 18.1% by mass, a solution viscosity of 5.1 Pa ⁇ s, and a logarithmic viscosity of 0.67.
- 1% by mass of an epoxy resin was added to the obtained polyamic acid solution to obtain a binder resin composition for electrodes.
- the copper foil coated with the electrode binder resin composition was fixed on a substrate, defoamed and pre-dried at 25 ° C. under reduced pressure for 30 minutes, and then placed in a hot air drier under normal pressure and nitrogen gas atmosphere. And a heat treatment at 120 ° C. for 1 hour to form a binder resin film having a thickness of 25 ⁇ m.
- a DMC swelling test was performed using a binder resin film formed on the copper foil as a sample. Further, an adhesion test and a 90 ° peel strength measurement were performed on the samples before and after the swelling test with a dimethyl carbonate solution. These results are shown in Table 1.
- the electrode binder composition (electrode) was prepared by kneading 4.5 g of the binder resin composition for an electrode (solid content mass after imidization 0.8 g) and 9.2 g of silicon powder of 325 mesh pass so as to be ground in a mortar.
- a mixture paste was prepared. The obtained paste could be thinly spread on the copper foil with a glass rod.
- the copper foil coated with the paste was fixed on the substrate, defoamed and pre-dried at 25 ° C. under reduced pressure for 30 minutes, and then placed in a hot air drier under normal pressure and nitrogen gas atmosphere at 120 ° C. for 1 hour. Heat treatment was performed to produce an electrode with an electrode mixture layer thickness of 100 ⁇ m.
- a DMC swelling test was performed using the obtained electrode as a sample. Moreover, the adhesion test was done about the sample before and behind the swelling test in a dimethyl carbonate solution.
- Example 17 Various tests were conducted in the same manner as in Example 16 except that 1% by mass of 1,3-PBO was added to the electrode binder resin composition instead of the epoxy resin. These results are shown in Table 3.
- Example 18 The test was conducted in the same manner as in Example 16 except that nothing was added to the electrode binder resin composition of Example 16. These results are shown in Table 3.
- the copper foil coated with the electrode binder resin composition was fixed on a substrate, defoamed and pre-dried at 25 ° C. under reduced pressure for 30 minutes, and then placed in a hot air drier under normal pressure and nitrogen gas atmosphere. And a heat treatment at 120 ° C. for 1 hour to form a binder resin film having a thickness of 25 ⁇ m.
- a DMC swelling test was performed using a binder resin film formed on the copper foil as a sample. Further, an adhesion test and a 90 ° peel strength measurement were performed on the samples before and after the swelling test with a dimethyl carbonate solution.
- the electrode binder composition (electrode) was prepared by kneading 4.4 g of the electrode binder resin composition (solid content after imidization 0.8 g) and 9.2 g of 325 mesh pass silicon powder so as to be ground in a mortar.
- a mixture paste was prepared. The obtained paste could be thinly spread on the copper foil with a glass rod.
- the copper foil coated with the paste was fixed on the substrate, defoamed and pre-dried at 25 ° C. under reduced pressure for 30 minutes, and then placed in a hot air drier under normal pressure and nitrogen gas atmosphere at 120 ° C. for 1 hour. Heat treatment was performed to produce an electrode with an electrode mixture layer thickness of 100 ⁇ m.
- a DMC swelling test was performed using the obtained electrode as a sample. Moreover, the adhesion test was done about the sample before and behind the swelling test in a dimethyl carbonate solution.
- the electrode binder composition (electrode) was prepared by kneading 4.4 g of the electrode binder resin composition (solid content after imidization 0.8 g) and 9.2 g of 325 mesh pass silicon powder so as to be ground in a mortar.
- a mixture paste was prepared. The obtained paste could be thinly spread on the copper foil with a glass rod.
- the copper foil coated with the paste was fixed on the substrate, defoamed and pre-dried at 25 ° C. under reduced pressure for 30 minutes, and then placed in a hot air drier under normal pressure and nitrogen gas atmosphere at 120 ° C. for 1 hour. Heat treatment was performed to produce an electrode with an electrode mixture layer thickness of 100 ⁇ m.
- a DMC swelling test was performed using the obtained electrode as a sample. Moreover, the adhesion test was done about the sample before and behind the swelling test in a dimethyl carbonate solution.
- the copper foil coated with the electrode binder resin composition was fixed on a substrate, defoamed and pre-dried at 25 ° C. under reduced pressure for 30 minutes, and then placed in a hot air drier under normal pressure and nitrogen gas atmosphere. And a heat treatment at 120 ° C. for 1 hour to form a binder resin film having a thickness of 25 ⁇ m.
- a DMC swelling test was performed using a binder resin film formed on the copper foil as a sample. Further, an adhesion test and a 90 ° peel strength measurement were performed on the samples before and after the swelling test with a dimethyl carbonate solution.
- the electrode binder composition (electrode) was prepared by kneading 4.4 g of the electrode binder resin composition (solid content after imidization 0.8 g) and 9.2 g of 325 mesh pass silicon powder so as to be ground in a mortar.
- a mixture paste was prepared. The obtained paste could be thinly spread on the copper foil with a glass rod.
- the copper foil coated with the paste was fixed on the substrate, defoamed and pre-dried at 25 ° C. under reduced pressure for 30 minutes, and then placed in a hot air drier under normal pressure and nitrogen gas atmosphere at 120 ° C. for 1 hour. Heat treatment was performed to produce an electrode with an electrode mixture layer thickness of 100 ⁇ m.
- a DMC swelling test was performed using the obtained electrode as a sample. Moreover, the adhesion test was done about the sample before and behind the swelling test in a dimethyl carbonate solution.
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Abstract
Description
このため、非常に大きな体積変化に対しても電極の破壊や剥離を起こしにくい、電池環境下での靭性が高い電極用のバインダーが望まれていた。
特許文献2には、電解液に対する膨潤度が小さく、優れた靱性(大きな破断伸度及び破断エネルギー)を有する、特定のポリアミック酸と溶剤とからなる電極用バインダー樹脂組成物が記載されている。また、電極を製造する際にはイミド化反応が十分に進行するよう、比較的高い温度での加熱処理が必要であることが記載されている。
特許文献3には、カルボキシル基を有するポリイミド樹脂とエポキシ樹脂とを含有するリチウムイオン二次電池の電極用樹脂組成物が記載されている。
また、近年、電池用の集電体(銅箔など)は極薄化が進んで厚さが10μm以下のものが使用されるようになり、電極製造工程で集電体が高温に曝されると機械強度が大幅に低下するなどの問題が生じることから、200℃以下の比較的低温で熱処理することが望まれている。
1. 集電体の表面に、少なくとも電極活物質と下記化学式(1)で表される繰返し単位を有するポリアミド酸からなるバインダーを含有する電極合剤組成物によって電極合剤層を形成し、次いで加熱処理して溶媒を除去するとともにポリアミド酸のイミド化反応を行うことを特徴とする電極の製造方法。
2. 電極合剤組成物が、さらにエポキシ基又はオキサゾリン基を有する架橋剤を含有することを特徴とする項1に記載の電極の製造方法。
3. 電極合剤組成物が、さらにピリジン類化合物を含有することを特徴とする項1又は2に記載の電極の製造方法。
4. 電極活物質が、炭素粉末、ケイ素粉末、スズ粉末、またはケイ素若しくはスズを含む合金粉末であることを特徴とする項1~3のいずれかに記載の電極の製造方法。
5. 電極活物質が、リチウム遷移金属酸化物であることを特徴とする項1~4のいずれかに記載の電極の製造方法。
6. リチウムイオン二次電池用電極を得ることを特徴とする項1~5のいずれかに記載の電極の製造方法。
集電体は、必要に応じて表面粗さが制御され、例えば平板状、メッシュ状、ネット状、ラス状、パンチングメタル状、エンボス状などの箔以外の形状であっても構わない。
本発明で用いる電極合剤組成物の電極活物質は、電池で通常用いられるものであれば限定されるものではない。負極の場合は、リチウムを電気化学的に挿入、脱離することができる物質であればよく、例えば黒鉛、コークス類、カーボンブラック、熱分解炭素などの炭素粉末、ケイ素粉末、スズ粉末、またはケイ素若しくはスズを含む合金粉末を挙げることができる。合金粉末はケイ素若しくはスズと金属元素との金属間化合物であることが好ましく、金属元素としてはニッケル、チタン、鉄、コバルト、銅、ジルコン、マンガンなどの遷移金属であることが好ましい。正極の場合は、リチウム元素を有し、リチウムを電気化学的に脱離、挿入することができる物質であればよく、例えばLiCoO2、LiNiO2、LiMnO2,LiCo0.5Mn0.5O2,LiNi0.7Co0.2Mn0.1O2などのリチウム遷移金属酸化物を好適に挙げることができる。
このポリアミド酸は、溶媒中でテトラカルボン酸成分とジアミン成分とをイミド化反応を抑制するために低温で反応させることによって容易に調製することができる。
テトラカルボン酸成分は、テトラカルボン酸類すなわちテトラカルボン酸、その酸二無水物及びそのエステル化化合物などであり、好ましくは二無水物である。
1~4個の芳香族環を有する芳香族ジアミンとしては、例えばp-フェニレンジアミン、m-フェニレンジアミン、2,4-ジアミノトルエン、2,4-ビス(β-アミノ-第三ブチル)トルエン、ビス-p-(1,1-ジメチル-5-アミノ-ペンチル)ベンゼン、1-イソプロピル-2,4-m-フェニレンジアミン、m-キシリレンジアミン、p-キシリレンジアミンなどの1個の芳香族環を有する芳香族ジアミン;
4,4’-ジアミノジフェニルエーテル、4,4’-ジアミノジフェニルメタン、3,3’-ジアミノジフェニルメタン、3,3’-ジクロロベンジジン、4,4’-ジアミノジフェニルスルフィド、3,3’-ジアミノジフェニルスルホン、1,5-ジアミノナフタレン、3,3’-ジメチル-4,4’-ビフェニルジアミン、ベンジジン、3,3’-ジメチルベンジジン、3,3’-ジメトキシベンジジン、4,4’-ジアミノジフェニルスルホン、4,4’-ジアミノジフェニルプロパン、ビス(4-アミノ-3-カルボキシフェニル)メタン、ビス(p-β-アミノ-第三ブチルフェニル)エーテルなどの2個の芳香族環を有する芳香族ジアミン;
1,3-ビス(4-アミノフェノキシ)ベンゼン、1,4-ビス(4-アミノフェノキシ)ベンゼン、ビス(p-β-メチル-6-アミノフェニル)ベンゼンなどの3個の芳香族環を有する芳香族ジアミン;
2,2-ビス〔4-(4-アミノフェノキシ)フェニル〕プロパン、ビス〔4-(4-アミノフェノキシ)フェニル〕スルホン、4,4’-ビス(4-アミノフェノキシ)ビフェニルなどの4個の芳香族環を有する芳香族ジアミン;を好適に挙げることができる。
また溶液粘度は、30℃における溶液粘度が、好ましくは1000Pa・s以下、より好ましくは0.5~500Pa・s、さらに好ましくは1~300Pa・s、特に好ましくは3~200Pa・sである。溶液粘度が1000Pa・sを超えると、電極活物質粉末の混合や集電体上への均一な塗布が困難となり、0.5Pa・sよりも低いと、電極活物質粉末の混合や集電体上への塗布時にたれなどが生じ、加熱乾燥、イミド化後のポリイミド樹脂の靭性が低くなる恐れがある。
ピリジン類化合物は、化学構造中にピリジン骨格を有する化合物のことであり、例えばピリジン、3-ピリジノール、キノリン、イソキノリン、キノキサリン、6-tert-ブチルキノリン、アクリジン、6-キノリンカルボン酸、3,4-ルチジン、ピリダジンなどを好適に挙げることができる。これらのピリジン系化合物は、単独または2種以上併用して使用しても差し支えない。
加熱処理温度が80℃以下の場合、イミド化反応が十分に進行しなかったり、電極成形体の物性が低下したりすることがある。また、200℃を超えると集電体が劣化する恐れがある。加熱処理は発泡や粉末化を防ぐために多段で段階的に昇温させる方法で行ってもよい。加熱処理時間は10分~48時間の範囲が好ましい。48時間以上は生産性の点から好ましくなく、10分よりも短いとイミド化反応や溶媒の除去が不十分となることがある。
この間に、ほとんどの溶媒が除かれ、且つポリアミド酸はイミド化反応によって実質的にポリイミドになる。加熱処理は、効率よく溶媒を除くために、減圧下条件下や不活性ガス流条件下で好適に行うことができる。
ここで、実質的にポリイミドになるとは、ポリイミド中にアミド酸構造が残存してもよいことを意味しており、アミド酸構造中の70%以上、好ましくは80%以上、より好ましく90%以上がイミド化されていればよい。この程度の低温での加熱処理によってアミド酸構造を完全にイミド化することは必ずしも容易ではない。しかしながら、本発明の特定のテトラカルボン酸成分とジアミン成分とから構成される繰り返し単位からなるポリアミド酸からなるバインダーは、この程度の低温の加熱処理によって、電池環境下でも膨潤度が小さく(ジメチルカーボネートに25℃で24時間浸漬したときの膨潤による質量増加率が好ましくは2質量%以下より好ましくは1質量%以下である)且つ優れた付着性(集電体との90°ピール強度が0.5N/mm以上、より好ましくは0.7N/mm以上であり、且つ25℃で24時間ジメチルカーボネートに浸漬した後の90°ピール強度の保持率が80%以上、より好ましくは85%以上、さらに好ましくは90%以上であり、また集電体とのクロスカット法による付着性試験で、剥離が5%未満であり、且つ25℃で24時間ジメチルカーボネートに浸漬した後の剥離も5%未満である)や靱性を保つことができるという高性能電池のバインダーとして要求される優れた特性を発現することができる。90°ピール強度測定やクロスカット法による付着性試験の詳細は後述する。
<固形分濃度>
試料溶液(その質量をw1とする)を、熱風乾燥機中120℃で10分間、250℃で10分間、次いで350℃で30分間加熱処理して、加熱処理後の質量(その質量をw2とする)を測定する。固形分濃度[質量%]は、次式によって算出した。
固形分濃度[質量%]=(w2/w1)×100
試料溶液を、固形分濃度に基づいて濃度が0.5g/dl(溶媒はNMP)になるように希釈した。この希釈液について、30℃にて、キャノンフェンスケNo.100を用いて流下時間(T1)を測定した。対数粘度は、ブランクのNMPの流下時間(T0)を用いて、次式から算出した。
対数粘度={ln(T1/T0)}/0.5
試料溶液を、トキメック社製E型粘度計を用いて30℃で測定した。
試料溶液を、25℃の温度に調整された雰囲気中に保管し、1ヶ月後の溶液粘度変化が±10%以内のものを○、±10%を超えたものを×とした。溶液粘度変化は、{(1ヶ月保管後の溶液粘度-保管前の溶液粘度)/保管前の溶液粘度}×100で定義される。
銅箔と電極合剤層からなる電極を5cm角に切り出したものを試料とし、電極合剤層単独の質量は計算によって銅箔の質量を減じることによって求めることとし、以下のジメチルカーボネート(DMC)溶液での膨潤試験によって電極合剤層の膨潤度Sを測定した。すなわち、25℃で24時間真空乾燥後の電極合剤層の質量を乾燥質量(Wd)とし、ジメチルカーボネート溶液に25℃で24時間浸漬後の電極合剤層の質量を膨潤質量(Ww)とし、次式により膨潤度Sを計算した。
S[質量%]={(Ww-Wd)/Ww}×100
付着性試験は、JIS K 5600-5-6に準拠して行った。なお、評価は目視により、評価基準(3)に準拠した分類0~分類5(数字が小さいほど強固に付着している)で示した。
なお、付着性試験は、ジメチルカーボネート溶液での膨潤試験前後の試料について、それぞれ行った。
90°ピール強度試験は、万能試験機(オリエンテック社製RTC-1225A)を用いて、IPC-TM650に準拠して測定した。
ジメチルカーボネート溶液での膨潤試験前後の試料について、90°ピール強度を測定し、次式により90°ピール強度の保持率を算出した。
90°ピール強度保持率[%]
=(浸漬後の90°ピール強度/浸漬前の90°ピール強度)×100
ODPA:4,4’-オキシジフタル酸二無水物
s-BPDA:3,3’,4,4’-ビフェニルテトラカルボン酸二無水物
PPD:p-フェニレンジアミン
ODA:4,4’-ジアミノジフェニルエーテル
HMD:ヘキサメチレンジアミン
3,5-DABA:3,5-ジアミノ安息香酸
MBAA:4,4’-ジアミノ-3,3’-ジカルボキシジフェニルメタン
1,3-PBO:1,3-フェニレンビスオキサゾリン
撹拌機、窒素ガス導入・排出管を備えた内容積500mLのガラス製の反応容器に、溶媒としてNMPを400g加え、これに36.81g(0.184モル)のODA及び3.11g(0.020モル)の3,5-DABAと、60.09g(0.204モル)のs-BPDAとを加え、50℃で10時間撹拌して、固形分濃度18.2質量%、溶液粘度5.3Pa・s、対数粘度0.62のポリアミド酸溶液を得た。
得られたポリアミド酸溶液に1質量%のエポキシ樹脂を添加し電極用バインダー樹脂組成物を得た。
前記電極用バインダー樹脂組成物を塗布した銅箔を基板上に固定し、減圧下25℃で30分間、脱泡及び予備乾燥した後で、常圧下、窒素ガス雰囲気下に熱風乾燥器に入れて、120℃で1時間加熱処理して、厚さが25μmのバインダー樹脂フィルムを形成した。
銅箔上に形成したバインダー樹脂フィルムを試料としてDMC膨潤試験を行った。またジメチルカーボネート溶液での膨潤試験前後の試料について付着性試験及び90°ピール強度測定を行った。
これらの結果を表1に示した。
ペーストを塗布した銅箔を基板上に固定し、減圧下25℃で30分間、脱泡及び予備乾燥した後で、常圧下、窒素ガス雰囲気下に熱風乾燥器に入れて、120℃で1時間加熱処理して、電極合剤層の厚みが100μmの電極を作製した。
得られた電極を試料としてDMC膨潤試験を行った。またジメチルカーボネート溶液での膨潤試験前後の試料について付着性試験を行った。
これらの結果を表1に示した。
電極用バインダー樹脂組成物にエポキシ樹脂の代わりに1,3-PBOを1質量%添加した以外は実施例1と同様にして各種試験を行った。
これらの結果を表1に示した。
実施例1の電極用バインダー樹脂組成物に何も添加しなかったこと以外は実施例1と同様にして試験を行った。
これらの結果を表1に示した。
撹拌機、窒素ガス導入・排出管を備えた内容積500mLのガラス製の反応容器に、溶媒としてNMPの400gを加え、これにODAの35.83g(0.179モル)及びMBAAの5.69g(0.020モル)と、s-BPDAの58.48g(0.199モル)とを加え、50℃で10時間撹拌して、固形分濃度18.1質量%、溶液粘度5.1Pa・s、対数粘度0.65のポリアミド酸溶液を得た。
得られたポリアミド酸溶液に1質量%のエポキシ樹脂を添加し電極用バインダー樹脂組成物を得た。
前記電極用バインダー樹脂組成物を塗布した銅箔を基板上に固定し、減圧下25℃で30分間、脱泡及び予備乾燥した後で、常圧下、窒素ガス雰囲気下に熱風乾燥器に入れて、120℃で1時間加熱処理して、厚さが25μmのバインダー樹脂フィルムを形成した。
銅箔上に形成したバインダー樹脂フィルムを試料としてDMC膨潤試験を行った。またジメチルカーボネート溶液での膨潤試験前後の試料について付着性試験及び90°ピール強度測定を行った。
これらの結果を表2に示した。
ペーストを塗布した銅箔を基板上に固定し、減圧下25℃で30分間、脱泡及び予備乾燥した後で、常圧下、窒素ガス雰囲気下に熱風乾燥器に入れて、120℃で1時間加熱処理して、電極合剤層の厚みが100μmの電極を作製した。
得られた電極を試料としてDMC膨潤試験を行った。またジメチルカーボネート溶液での膨潤試験前後の試料について付着性試験を行った。
これらの結果を表1に示した。
電極用バインダー樹脂組成物にエポキシ樹脂の代わりに1,3-PBOを1質量%添加した以外は実施例4と同様にして各種試験を行った。
これらの結果を表1に示した。
実施例4の電極用バインダー樹脂組成物に何も添加しなかったこと以外は実施例4と同様にして試験を行った。
これらの結果を表1に示した。
撹拌機、窒素ガス導入・排出管を備えた内容積500mLのガラス製の反応容器に、溶媒としてNMPの400gを加え、これにODAの13.20g(0.066モル)、3,5-DABAの3.34g(0.022モル)及びHMDの15.32g(0.132モル)と、ODPAの68.14g(0.220モル)とを加え、50℃で10時間撹拌して、固形分濃度17.9質量%、溶液粘度5.0Pa・s、対数粘度0.71のポリアミド酸溶液を得た。
得られたポリアミド酸溶液に1質量%のエポキシ樹脂を添加し電極用バインダー樹脂組成物を得た。
前記電極用バインダー樹脂組成物を塗布した銅箔を基板上に固定し、減圧下25℃で30分間、脱泡及び予備乾燥した後で、常圧下、窒素ガス雰囲気下に熱風乾燥器に入れて、120℃で1時間加熱処理して、厚さが25μmのバインダー樹脂フィルムを形成した。
銅箔上に形成したバインダー樹脂フィルムを試料としてDMC膨潤試験を行った。またジメチルカーボネート溶液での膨潤試験前後の試料について付着性試験及び90°ピール強度測定を行った。
これらの結果を表2に示した。
ペーストを塗布した銅箔を基板上に固定し、減圧下25℃で30分間、脱泡及び予備乾燥した後で、常圧下、窒素ガス雰囲気下に熱風乾燥器に入れて、120℃で1時間加熱処理して、電極合剤層の厚みが100μmの電極を作製した。
得られた電極を試料としてDMC膨潤試験を行った。またジメチルカーボネート溶液での膨潤試験前後の試料について付着性試験を行った。
これらの結果を表2に示した。
電極用バインダー樹脂組成物にエポキシ樹脂の代わりに1,3-PBOを1質量%添加した以外は実施例7と同様にして各種試験を行った。
〔実施例9〕
実施例7の電極用バインダー樹脂組成物に何も添加しなかったこと以外は実施例7と同様にして試験を行った。
これらの結果を表2に示した。
撹拌機、窒素ガス導入・排出管を備えた内容積500mLのガラス製の反応容器に、溶媒としてNMPの400gを加え、これにODAの12.82g(0.064モル)、MBAAの6.11g(0.021モル)及びHMDの14.88g(0.128モル)と、ODPAの66.19g(0.213モル)とを加え、50℃で10時間撹拌して、固形分濃度18.0質量%、溶液粘度4.9Pa・s、対数粘度0.73のポリアミド酸溶液を得た。
得られたポリアミド酸溶液に1質量%のエポキシ樹脂を添加し電極用バインダー樹脂組成物を得た。
前記電極用バインダー樹脂組成物を塗布した銅箔を基板上に固定し、減圧下25℃で30分間、脱泡及び予備乾燥した後で、常圧下、窒素ガス雰囲気下に熱風乾燥器に入れて、120℃で1時間加熱処理して、厚さが25μmのバインダー樹脂フィルムを形成した。
銅箔上に形成したバインダー樹脂フィルムを試料としてDMC膨潤試験を行った。またジメチルカーボネート溶液での膨潤試験前後の試料について付着性試験及び90°ピール強度測定を行った。
これらの結果を表2に示した。
ペーストを塗布した銅箔を基板上に固定し、減圧下25℃で30分間、脱泡及び予備乾燥した後で、常圧下、窒素ガス雰囲気下に熱風乾燥器に入れて、120℃で1時間加熱処理して、電極合剤層の厚みが100μmの電極を作製した。
得られた電極を試料としてDMC膨潤試験を行った。またジメチルカーボネート溶液での膨潤試験前後の試料について付着性試験を行った。
これらの結果を表2に示した。
電極用バインダー樹脂組成物にエポキシ樹脂の代わりに1,3-PBOを1質量%添加した以外は実施例10と同様にして各種試験を行った。
これらの結果を表2に示した。
実施例10の電極用バインダー樹脂組成物に何も添加しなかったこと以外は実施例10と同様にして試験を行った。
これらの結果を表2に示した。
撹拌機、窒素ガス導入・排出管を備えた内容積500mLのガラス製の反応容器に、溶媒としてNMPの400gを加え、これにPPDの4.51g(0.042モル)、ODAの29.25g(0.146モル)及び3,5-DABAの3.18g(0.021モル)と、s-BPDAの30.70g(0.104モル)及びODPAの32.37g(0.104モル)とを加え、50℃で10時間撹拌して、固形分濃度18.2質量%、溶液粘度5.3Pa・s、対数粘度0.68のポリアミド酸溶液を得た。
得られたポリアミド酸溶液に1質量%のエポキシ樹脂を添加し電極用バインダー樹脂組成物を得た。
前記電極用バインダー樹脂組成物を塗布した銅箔を基板上に固定し、減圧下25℃で30分間、脱泡及び予備乾燥した後で、常圧下、窒素ガス雰囲気下に熱風乾燥器に入れて、120℃で1時間加熱処理して、厚さが25μmのバインダー樹脂フィルムを形成した。
銅箔上に形成したバインダー樹脂フィルムを試料としてDMC膨潤試験を行った。またジメチルカーボネート溶液での膨潤試験前後の試料について付着性試験及び90°ピール強度測定を行った。
これらの結果を表3に示した。
ペーストを塗布した銅箔を基板上に固定し、減圧下25℃で30分間、脱泡及び予備乾燥した後で、常圧下、窒素ガス雰囲気下に熱風乾燥器に入れて、120℃で1時間加熱処理して、電極合剤層の厚みが100μmの電極を作製した。
得られた電極を試料としてDMC膨潤試験を行った。またジメチルカーボネート溶液での膨潤試験前後の試料について付着性試験を行った。
これらの結果を表3に示した。
電極用バインダー樹脂組成物にエポキシ樹脂の代わりに1,3-PBOを1質量%添加した以外は実施例13と同様にして各種試験を行った。
これらの結果を表3に示した。
実施例13の電極用バインダー樹脂組成物に何も添加しなかったこと以外は実施例13と同様にして試験を行った。
これらの結果を表3に示した。
撹拌機、窒素ガス導入・排出管を備えた内容積500mLのガラス製の反応容器に、溶媒としてNMPの400gを加え、これにPPDの4.51g(0.042モル)、ODAの29.25g(0.146モル)及び3,5-DABAの3.18g(0.021モル)と、s-BPDAの30.70g(0.104モル)及びODPAの32.37g(0.104モル)とを加え、50℃で10時間撹拌して、固形分濃度18.1質量%、溶液粘度5.1Pa・s、対数粘度0.67のポリアミド酸溶液を得た。
得られたポリアミド酸溶液に1質量%のエポキシ樹脂を添加し電極用バインダー樹脂組成物を得た。
前記電極用バインダー樹脂組成物を塗布した銅箔を基板上に固定し、減圧下25℃で30分間、脱泡及び予備乾燥した後で、常圧下、窒素ガス雰囲気下に熱風乾燥器に入れて、120℃で1時間加熱処理して、厚さが25μmのバインダー樹脂フィルムを形成した。
銅箔上に形成したバインダー樹脂フィルムを試料としてDMC膨潤試験を行った。またジメチルカーボネート溶液での膨潤試験前後の試料について付着性試験及び90°ピール強度測定を行った。
これらの結果を表1に示した。
ペーストを塗布した銅箔を基板上に固定し、減圧下25℃で30分間、脱泡及び予備乾燥した後で、常圧下、窒素ガス雰囲気下に熱風乾燥器に入れて、120℃で1時間加熱処理して、電極合剤層の厚みが100μmの電極を作製した。
得られた電極を試料としてDMC膨潤試験を行った。またジメチルカーボネート溶液での膨潤試験前後の試料について付着性試験を行った。
これらの結果を表3に示した。
電極用バインダー樹脂組成物にエポキシ樹脂の代わりに1,3-PBOを1質量%添加した以外は実施例16と同様にして各種試験を行った。
これらの結果を表3に示した。
実施例16の電極用バインダー樹脂組成物に何も添加しなかったこと以外は実施例16と同様にして試験を行った。
これらの結果を表3に示した。
攪拌機、窒素ガス導入・排出管を備えた内容積500mLのガラス製の反応容器に、溶媒としてNMPの400gを加え、これにODAの40.50g(0.202モル)と、s-BPDAの59.50g(0.202モル)とを加え、50℃で10時間撹拌して、固形分濃度18.4質量%、溶液粘度5.1Pa・s、対数粘度0.64のポリアミド酸溶液を得た。これをそのまま電極用バインダー樹脂組成物として用いた。
前記電極用バインダー樹脂組成物を塗布した銅箔を基板上に固定し、減圧下25℃で30分間、脱泡及び予備乾燥した後で、常圧下、窒素ガス雰囲気下に熱風乾燥器に入れて、120℃で1時間加熱処理して、厚さが25μmのバインダー樹脂フィルムを形成した。
銅箔上に形成したバインダー樹脂フィルムを試料としてDMC膨潤試験を行った。またジメチルカーボネート溶液での膨潤試験前後の試料について付着性試験及び90°ピール強度測定を行った。
これらの結果を表4に示した。
ペーストを塗布した銅箔を基板上に固定し、減圧下25℃で30分間、脱泡及び予備乾燥した後で、常圧下、窒素ガス雰囲気下に熱風乾燥器に入れて、120℃で1時間加熱処理して、電極合剤層の厚みが100μmの電極を作製した。
得られた電極を試料としてDMC膨潤試験を行った。またジメチルカーボネート溶液での膨潤試験前後の試料について付着性試験を行った。
これらの結果を表4に示した。
攪拌機、窒素ガス導入・排出管を備えた内容積500mLのガラス製の反応容器に、溶媒としてNMPの400gを加え、これにODAの29.52g(0.147モル)及びPPDの6.83g(0.063モル)と、s-BPDAの30.98g(0.105モル)及びODPA32.67g(0.105モル)のとを加え、50℃で10時間撹拌して、固形分濃度18.3質量%、溶液粘度4.8Pa・s、対数粘度0.69のポリアミド酸溶液を得た。これをそのまま電極用バインダー樹脂組成物として用いた。
前記電極用バインダー樹脂組成物を塗布した銅箔を基板上に固定し、減圧下25℃で30分間、脱泡及び予備乾燥した後で、常圧下、窒素ガス雰囲気下に熱風乾燥器に入れて、120℃で1時間加熱処理して、厚さが25μmのバインダー樹脂フィルムを形成した。
銅箔上に形成したバインダー樹脂フィルムを試料としてDMC膨潤試験を行った。またジメチルカーボネート溶液での膨潤試験前後の試料について付着性試験及び90°ピール強度測定を行った。
これらの結果を表4に示した。
ペーストを塗布した銅箔を基板上に固定し、減圧下25℃で30分間、脱泡及び予備乾燥した後で、常圧下、窒素ガス雰囲気下に熱風乾燥器に入れて、120℃で1時間加熱処理して、電極合剤層の厚みが100μmの電極を作製した。
得られた電極を試料としてDMC膨潤試験を行った。またジメチルカーボネート溶液での膨潤試験前後の試料について付着性試験を行った。
これらの結果を表4に示した。
攪拌機、窒素ガス導入・排出管を備えた内容積500mLのガラス製の反応容器に、溶媒としてNMPの400gを加え、これにODAの17.41g(0.087モル)及びHMDの15.16g(0.130モル)と、ODPA67.43g(0.217モル)のとを加え、50℃で10時間撹拌して、固形分濃度18.5質量%、溶液粘度4.5Pa・s、対数粘度0.70のポリアミド酸溶液を得た。これをそのまま電極用バインダー樹脂組成物として用いた。
前記電極用バインダー樹脂組成物を塗布した銅箔を基板上に固定し、減圧下25℃で30分間、脱泡及び予備乾燥した後で、常圧下、窒素ガス雰囲気下に熱風乾燥器に入れて、120℃で1時間加熱処理して、厚さが25μmのバインダー樹脂フィルムを形成した。
銅箔上に形成したバインダー樹脂フィルムを試料としてDMC膨潤試験を行った。またジメチルカーボネート溶液での膨潤試験前後の試料について付着性試験及び90°ピール強度測定を行った。
これらの結果を表4に示した。
ペーストを塗布した銅箔を基板上に固定し、減圧下25℃で30分間、脱泡及び予備乾燥した後で、常圧下、窒素ガス雰囲気下に熱風乾燥器に入れて、120℃で1時間加熱処理して、電極合剤層の厚みが100μmの電極を作製した。
得られた電極を試料としてDMC膨潤試験を行った。またジメチルカーボネート溶液での膨潤試験前後の試料について付着性試験を行った。
これらの結果を表4に示した。
Claims (6)
- 集電体の表面に、少なくとも電極活物質と下記化学式(1)で表される繰返し単位を有するポリアミド酸からなるバインダーを含有する電極合剤組成物によって電極合剤層を形成し、次いで加熱処理して溶媒を除去するとともにポリアミド酸のイミド化反応を行うことを特徴とする電極の製造方法。
- 電極合剤組成物が、さらにエポキシ基又はオキサゾリン基を有する架橋剤を含有することを特徴とする請求項1に記載の電極の製造方法。
- 電極合剤組成物が、さらにピリジン類化合物を含有することを特徴とする請求項1又は2に記載の電極の製造方法。
- 電極活物質が、炭素粉末、ケイ素粉末、スズ粉末、またはケイ素若しくはスズを含む合金粉末であることを特徴とする請求項1~3のいずれか一項に記載の電極の製造方法。
- 電極活物質が、リチウム遷移金属酸化物であることを特徴とする請求項1~4のいずれか一項に記載の電極の製造方法。
- リチウムイオン二次電池用電極を得ることを特徴とする請求項1~5のいずれか一項に記載の電極の製造方法。
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JP7158124B2 (ja) | 2022-10-21 |
CN106165164A (zh) | 2016-11-23 |
JP2015213061A (ja) | 2015-11-26 |
TWI657613B (zh) | 2019-04-21 |
US20170025671A1 (en) | 2017-01-26 |
CN106165164B (zh) | 2019-01-22 |
TW201607127A (zh) | 2016-02-16 |
KR102443793B1 (ko) | 2022-09-19 |
US9685654B2 (en) | 2017-06-20 |
EP3133680A1 (en) | 2017-02-22 |
EP3133680A4 (en) | 2017-12-13 |
KR20160145567A (ko) | 2016-12-20 |
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