WO2019107054A1 - Method for producing paste for negative electrode production, negative electrode for batteries, battery, and method for producing negative electrode for batteries - Google Patents

Method for producing paste for negative electrode production, negative electrode for batteries, battery, and method for producing negative electrode for batteries Download PDF

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Publication number
WO2019107054A1
WO2019107054A1 PCT/JP2018/040535 JP2018040535W WO2019107054A1 WO 2019107054 A1 WO2019107054 A1 WO 2019107054A1 JP 2018040535 W JP2018040535 W JP 2018040535W WO 2019107054 A1 WO2019107054 A1 WO 2019107054A1
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Prior art keywords
negative electrode
paste
producing
mass
manufacturing
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PCT/JP2018/040535
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French (fr)
Japanese (ja)
Inventor
慎二 小路
健人 高橋
安孝 河野
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Ｎｅｃエナジーデバイス株式会社
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Priority to JP2019557085A priority Critical patent/JPWO2019107054A1/en
Publication of WO2019107054A1 publication Critical patent/WO2019107054A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • 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
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • 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
    • 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

Definitions

  • the present invention relates to a method for producing a paste for producing a negative electrode, a battery negative electrode, a battery and a method for producing a battery negative electrode.
  • a negative electrode used in a battery is mainly composed of a negative electrode active material layer and a current collector layer.
  • the negative electrode active material layer can be obtained, for example, by applying a negative electrode production paste containing a negative electrode active material, a thickener, an aqueous binder and the like on the surface of a current collector layer such as metal foil and drying.
  • Patent Document 1 Japanese Patent No. 5396989
  • the carbon powder 1a and the CMC powder 1b are introduced, and mixed in a powder-only state to form a powder mixture 1, and then the viscosity, particle size and peel strength of the paste are obtained.
  • the amount of dispersion medium input and the solidifying time are determined on the basis of each correlation with the above, and divided into two steps of the coarse mixing process and the solid mixing process, and the water as the dispersion medium is added, lithium ion secondary battery A method of producing the paste used for production is described.
  • the negative electrode for a battery obtained by the conventional manufacturing method may have low peel strength, and there is room for improvement in the adhesion between the current collector layer and the negative electrode active material layer. It became clear.
  • the peel strength of the negative electrode for battery is low, productivity of the electrode or battery is reduced, and powdering of the negative electrode active material layer occurs in the process of assembling the battery. As a result, battery quality deterioration, battery cycle characteristics, etc. There is a concern that problems may occur in
  • Patent Document 1 Japanese Patent No. 5396989
  • Japanese Patent No. 5396989 Japanese Patent No. 5396989
  • the solid content concentration in each step if the correlation with the viscosity, particle size and peel strength of the paste is not required, There is a problem that it is difficult to calculate the solid concentration.
  • the solid concentration is too high, in the process of stirring and mixing the paste using a mixer, the powder mixture rises up to the edge of the mixer during wet mixing, so the obtained paste becomes uneven, and As a result, there is a problem that the viscosity and peel strength of the negative electrode produced by applying and drying the above paste for negative electrode are not constant, and the performance of a battery produced using the above negative electrode is not constant.
  • the present invention has been made in view of the above circumstances, and a method for producing a paste for producing a negative electrode capable of stably obtaining a negative electrode for a battery excellent in adhesion between the current collector layer and the negative electrode active material layer.
  • the present inventors diligently studied to achieve the above object.
  • one or two or more types of liquid components selected from an aqueous solution and an aqueous emulsion solution containing an aqueous binder are added to a mixture containing at least a dry mixed negative electrode active material and a thickener, and wet mixed,
  • the solid content concentration in the first solidifying step is set to 68% by mass or more and 79% by mass or lower after the first solidifying step and the second solidifying step are performed in two steps.
  • a negative electrode for a battery having excellent adhesiveness between the current collector layer and the negative electrode active material layer by using the method for producing a negative electrode production paste in which the solid content concentration in the kneading step is set to 59 mass% to 66 mass%. It came to complete the present invention by finding that it could obtain stably.
  • Preparing a mixture containing at least the negative electrode active material and the thickener by dry-mixing a plurality of powdery materials containing at least a negative electrode active material and a thickener in a powder state; Preparing a paste precursor by adding one or two or more kinds of liquid components selected from an aqueous solution of an aqueous medium and an aqueous binder to the mixture and wet mixing them, and (B) A step of preparing a paste for negative electrode production by further adding one or two or more types of liquid components selected from the aqueous solution and the aqueous emulsion containing the aqueous binder to the paste precursor and wet mixing C) and A method for producing a paste for producing a negative electrode, comprising The step (B) includes at least a first solidifying step (B2) and a second solidifying step (B3), The solid content concentration in the first solidifying step (B2) is 68% by mass to 79% by mass, and the solid concentration in the second
  • the present inventors can control the viscosity of the paste for producing a negative electrode within a certain range by using the above-described method for producing a paste for producing a negative electrode, and as a result, using the produced paste for producing a negative electrode
  • the step of continuously forming the negative electrode active material layer on the current collector layer by applying the negative electrode production paste to the current collector layer and drying it, and removing the aqueous medium, is stable. Was found to be able to control the
  • the paste for producing a negative electrode obtained by the method for producing a paste for producing a negative electrode according to the present invention is applied to a current collector layer and dried, and the aqueous medium is removed to obtain the above-mentioned negative electrode active on the current collector layer.
  • a method of manufacturing a battery negative electrode including the step of forming a material layer is provided.
  • a current collector layer comprising: a negative electrode active material layer provided on at least one surface of the current collector layer and formed of the solid content of the negative electrode production paste obtained by the method for producing a negative electrode production paste of the present invention A negative electrode is provided.
  • a battery comprising at least a positive electrode, an electrolyte and a negative electrode, There is provided a battery including the above-described negative electrode for a battery according to the present invention.
  • the paste for negative electrode manufacture which can obtain stably the negative electrode for batteries excellent in the adhesiveness of a collector layer and a negative electrode active material layer can be provided.
  • each component schematically shows the shape, size and arrangement relationship to the extent that the present invention can be understood, and is different from the actual size.
  • a layer containing a negative electrode active material is called a negative electrode active material layer
  • a layer in which a negative electrode active material layer is formed on a current collector layer is called an electrode.
  • a to B in the numerical value range represent A or more and B or less unless otherwise specified.
  • the method for producing a paste for producing a negative electrode according to the present embodiment is a method for producing a paste for producing a negative electrode for a battery, which comprises a negative electrode active material, an aqueous binder, a thickener, and an aqueous medium.
  • Preparing a mixture containing at least the negative electrode active material and the thickener by dry-mixing a plurality of powdery materials containing at least a negative electrode active material and a thickener in a powder state; Preparing a paste precursor by adding one or two or more kinds of liquid components selected from an aqueous solution of an aqueous medium and an aqueous binder to the mixture and wet mixing them, and (B) A step of preparing the paste for producing a negative electrode by further adding one or two or more kinds of liquid components selected from the aqueous medium and the aqueous emulsion containing the aqueous binder to the paste precursor and wet mixing them.
  • the step (B) includes at least a first solidifying step (B2) and a second solidifying step (B3),
  • the solid content concentration in the first solidifying step (B2) is 68% by mass to 79% by mass
  • the solid concentration in the second solidifying step (B3) is 59% by mass to 66% by mass
  • This is a method for producing a paste for producing a negative electrode.
  • the thickener is dissolved in the paste for manufacturing a negative electrode and is not in a powder state.
  • the battery according to the present embodiment is, for example, a lithium ion primary battery or a lithium ion secondary battery, preferably a lithium ion secondary battery.
  • the negative electrode for a battery obtained by the conventional manufacturing method may have low peel strength in some cases, and the adhesion between the current collector layer and the negative electrode active material layer is improved. It became clear that there was room for When the peel strength of the negative electrode for battery is low, productivity of the electrode or battery is reduced, and powdering of the negative electrode active material layer occurs in the process of assembling the battery. As a result, battery quality deterioration, battery cycle characteristics, etc. There is a concern that problems may occur in
  • the present inventors diligently studied to achieve the above object. As a result, after the precursor production process of the paste for negative electrode production is made into two or more steps of the first solidifying process (B2) and the second solidifying process (B3), the first solidifying process (B2) is performed. Manufacturing the paste for negative electrode manufacture which sets the solid content concentration in 68) to 79 mass% and sets the solid concentration in the said 2nd solidifying process (B3) to 59 mass% to 66 mass%. By using the method, it has been found that the battery negative electrode having excellent adhesion between the current collector layer and the negative electrode active material layer can be stably obtained, and the present invention has been completed.
  • the solid content concentration in the first solidifying step (B2) is 68% by mass to 79% by mass
  • the solid concentration in the second solidifying step (B3) is 59% by mass to 66%. It is not always clear why the battery negative electrode having excellent adhesion between the current collector layer and the negative electrode active material layer can be stably obtained by using the method for producing a negative electrode production paste having% or less. However, the following reasons can be considered. First, it is considered that by performing the first solidifying step (B2) in a state where the solid content concentration is 68% by mass to 79% by mass, a certain amount of thickener is adsorbed to the active material and the conductive additive. . Thereby, excessive dispersion of the thickener in the aqueous medium is suppressed.
  • the active material and the conductive auxiliary agent are mixed in the subsequent second solidifying step (B3) so that the solid content concentration is 59% by mass or more and 66% by mass or less, the first solidifying step described above It is considered that the thickener adsorbed in the step (B2) is dispersed in the aqueous medium while being adsorbed on the surface. On the other hand, the remaining thickener which is not adsorbed to the active material and the conductive auxiliary agent in the first solidifying step (B2) is also dispersed in the aqueous medium.
  • the paste precursor for producing a negative electrode thus obtained, most of the active material and the conductive additive are present on the surface as an aggregate in which a thickener having excellent adsorptivity with a water-based binder is adsorbed. Therefore, when the aqueous binder is added and wet mixed in the subsequent step of preparing the paste for negative electrode production paste and wet mixed, the aqueous binder is efficiently adsorbed to the above aggregate, and the three-dimensional by the interaction between the respective materials Network is considered to develop. Furthermore, the remaining thickener which has not been adsorbed to the active material or the conductive aid is appropriately dispersed in the aqueous medium.
  • the paste for manufacturing a negative electrode is applied to the current collector layer and dried, and then the aqueous medium is removed to form the negative electrode active material layer on the current collector layer,
  • the thickener dispersed in the paste suppresses the movement of the water-based binder to the surface of the negative electrode active material layer during drying, and as a result, uneven distribution of the water-based binder on the surface of the negative electrode active material layer can be suppressed it is conceivable that.
  • the amount of the aqueous binder at the interface between the current collector layer and the negative electrode active material layer can be increased. It is believed that adhesion to the layer, ie peel strength, can be improved.
  • the solid content concentration in the first solidifying step (B2) is 68% by mass to 79% by mass
  • the second solidifying By using the method for producing a paste for producing a negative electrode having a solid content concentration of 59% by mass to 66% by mass in the step (B3), uneven distribution of the aqueous binder on the surface of the negative electrode active material layer can be suppressed.
  • the adhesion between the layer and the negative electrode active material layer, that is, the peel strength can be improved.
  • the paste for negative electrode manufacture which can obtain stably the negative electrode for batteries excellent in the adhesiveness of a collector layer and a negative electrode active material layer can be provided.
  • the lower limit of the solid content concentration in the first step of solidifying (B2) in the process of producing the paste for producing a negative electrode according to this embodiment is 68 mass%, preferably 70 mass% or more, more preferably 71 mass % Or more.
  • the solid content concentration in the first solidifying step (B2) is set to the above lower limit value or more to obtain a constant amount of thickener for the active material and the conductive additive. Can be adsorbed, thereby suppressing excessive dispersion of the thickener in the aqueous medium.
  • the active material and the conductive auxiliary agent are considered to be dispersed in the aqueous medium in the state of an aggregate in which the thickener is adsorbed on the surface also in the above-mentioned second solidifying step (B3). Since the thickener has better adsorptivity with the aqueous binder than the active material and the conductive auxiliary itself, the aqueous binder is efficiently adsorbed to the above-mentioned aggregate, and a three-dimensional network by interaction between each material Is considered to develop.
  • the upper limit of the solid content concentration in the first solidifying step (B2) in the process of producing the paste for producing a negative electrode according to the present embodiment is 79% by mass or less, preferably 77% by mass or less, more preferably 74 It is at most mass%, more preferably at most 72 mass%.
  • the powder mixture containing the active material and the conductive additive is wet mixed by setting the solid concentration in the first solidifying step (B2) to the upper limit value or less. Sometimes, it is possible to effectively suppress the rising of the edge of the mixer, so it is possible to obtain a paste for producing a negative electrode with a stable viscosity and mixing ratio.
  • the lower limit of the solid content concentration in the second solidifying step (B3) in the process of producing the paste for producing a negative electrode according to this embodiment is 59% by mass, preferably 61% by mass or more, more preferably 62% % Or more.
  • the solid content concentration in the second solidifying step (B3) is set to the above lower limit value or more to suppress the solid mixture from becoming a so-called lump state. , Uniform paste can be produced.
  • the upper limit of the solid content concentration in the second solidifying step (B3) in the process of producing the paste for producing a negative electrode according to the present embodiment is 66 mass% or less, preferably 64 mass% or less, more preferably 63 It is less than mass%.
  • the solid content concentration in the second solidifying step (B3) is set to the above upper limit value or less to activate in the first solidifying step (B2). It is considered that the remaining thickener which is not adsorbed to the substance or the conductive aid can be uniformly dispersed in the aqueous medium.
  • the paste for manufacturing a negative electrode is applied to the current collector layer and dried, and then the aqueous medium is removed to form the negative electrode active material layer on the current collector layer,
  • the thickener dispersed in the paste suppresses the movement of the water-based binder to the surface of the negative electrode active material layer during drying, and as a result, uneven distribution of the water-based binder on the surface of the negative electrode active material layer can be suppressed it is conceivable that.
  • the pH of the paste for manufacturing a negative electrode according to the present embodiment is, for example, 6.0 or more and 8.0 or less, preferably 6.5 or more and 7.5 or less, from the viewpoint of improving the dispersion stability of the paste for manufacturing a negative electrode. More preferably, they are 6.8 or more and 7.2 or less.
  • the method of adjusting the pH of the paste for negative electrode production according to the present embodiment is not particularly limited, but, for example, the blending ratio of each material constituting the paste for negative electrode production, the type of each material constituting the paste for negative electrode production, etc. It can be adjusted by adjusting.
  • the paste for manufacturing a negative electrode according to the present embodiment includes a negative electrode active material, an aqueous binder, a thickener, and an aqueous medium, and further contains a conductive auxiliary as required.
  • the peel strength improvement effect of the present embodiment is particularly effective. You can get it.
  • the negative electrode active material is not particularly limited as long as it is a common negative electrode active material that can be used for the battery negative electrode.
  • the battery is a lithium ion battery
  • carbon materials such as natural graphite, artificial graphite, resin charcoal, carbon fiber, activated carbon, hard carbon, soft carbon; lithium metals such as lithium metal, lithium alloy; silicon, tin, etc.
  • Conductive polymers such as polyacene, polyacetylene, polypyrrole and the like. Among these, carbon materials are preferable, and particularly graphitic materials such as natural graphite and artificial graphite are preferable.
  • the negative electrode active material may be used singly or in combination of two or more.
  • the content of the negative electrode active material is preferably 70 parts by mass or more and 99.97 parts by mass or less, and 85 parts by mass or more and 99.85 parts by mass, based on 100 parts by mass of the total solid content of the paste for negative electrode production It is more preferable that
  • the graphitic material is not particularly limited as long as it is an ordinary graphitic material usable for the negative electrode of the battery.
  • artificial graphite etc. which are manufactured by heat-processing natural graphite and petroleum type and coal type coke etc. are mentioned, for example.
  • natural graphite refers to graphite naturally produced as ore.
  • the natural graphite used as the core material of the present embodiment is not particularly limited in terms of production area, properties, and type.
  • artificial graphite refers to graphite made in an artificial manner and graphite close to a perfect crystal of graphite.
  • Such artificial graphite can be obtained, for example, by using tar and coke obtained from dry distillation of coal, residue of crude oil distillation and the like as a raw material and passing through a firing step and graphitization step.
  • the graphitic material has a graphite powder as a core material, and at least a part of the surface of the graphite powder is coated with a carbon material having a crystallinity lower than that of the graphite powder (hereinafter also referred to as surface-coated graphite).
  • a carbon material having a crystallinity lower than that of the graphite powder hereinafter also referred to as surface-coated graphite.
  • the edge portion of the graphite powder is preferably coated with the above-mentioned carbon material.
  • the binding property with the binder can be improved as compared to the case of using graphite alone, so that the amount of binder can be reduced. As a result, the battery characteristics of the obtained battery can be improved.
  • the carbon material having lower crystallinity than the above-mentioned graphite powder is, for example, amorphous carbon such as soft carbon and hard carbon.
  • graphite powder used as a core material examples include natural graphite, artificial graphite produced by heat-treating petroleum-based and coal-based coke, and the like.
  • these graphite powders may be used singly or in combination of two or more.
  • natural graphite is preferable in terms of cost.
  • the surface-coated graphite according to the present embodiment is a mixture of an organic compound which is carbonized in a firing step to become a carbon material having a lower crystallinity than the graphite powder, and the graphite powder, and then the carbonization of the organic compound is performed. It can be produced by
  • the organic compound to be mixed with the above-mentioned graphite powder is not particularly limited as long as it can be carbonized by firing to obtain a carbon material having a crystallinity lower than that of the above-mentioned graphite powder.
  • Tars such as petroleum pitches, pitches such as coal pitches; thermoplastic resins such as polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, polyvinyl alcohol, polyvinylidene chloride and polyacrylonitrile; heat such as phenol resin and furfuryl alcohol resin Curable resins; natural resins such as cellulose; and aromatic hydrocarbons such as naphthalene, alkyl naphthalene and anthracene.
  • these organic compounds may be used singly or in combination of two or more.
  • these organic compounds may be used as dissolved or dispersed in a solvent, as necessary.
  • tar and pitch are preferable in terms of price.
  • the ratio of the carbon material derived from the organic compound in the surface-coated graphite according to the present embodiment is preferably 0.7% by mass or more, based on 100% by mass of the negative electrode active material. It is 0 mass% or less.
  • the stability of the paste for negative electrode manufacture obtained can be improved by making the coating amount of a carbon material more than the said lower limit.
  • the coating amount can be calculated by thermogravimetric analysis. More specifically, when the temperature of the negative electrode active material is raised to 900 ° C. at a temperature rising rate of 5 ° C./min in an oxygen atmosphere using a thermogravimetric analyzer (for example, TGA7 analyzer manufactured by Perkin Elma Co., Ltd.) The reduced mass from the temperature at which the reduction started to the temperature at which the mass reduction rate becomes gradual and then the mass reduction accelerates can be used as the coating amount.
  • a thermogravimetric analyzer for example, TGA7 analyzer manufactured by Perkin Elma Co., Ltd.
  • the specific surface area of the negative electrode active material according to the nitrogen adsorption BET method is preferably 1.0 m 2 / g or more and 6.0 m 2 / g or less, more preferably 2.0 m 2 / g or more and 5.0 m 2 / g or less is there.
  • the specific surface area By setting the specific surface area to the upper limit value or less, it is possible to suppress the decrease in the initial charge / discharge efficiency due to the increase in the irreversible capacity.
  • the stability of the paste for negative electrode manufacture obtained can be improved by below a specific surface area being below the said upper limit.
  • the specific surface area to the above lower limit value or more the area for absorbing and releasing lithium ions can be increased, and the rate characteristics of the obtained lithium ion battery can be improved.
  • the binding property of the water-based binder can be improved by setting the specific surface area within the above range.
  • the average particle diameter of the negative electrode active material is preferably 1 ⁇ m or more, more preferably 3 ⁇ m or more, still more preferably 5 ⁇ m or more, and particularly preferably 8 ⁇ m or more, from the viewpoint of suppressing side reactions during charge and discharge and suppressing decrease in charge and discharge efficiency.
  • 50 ⁇ m or less is preferable, 40 ⁇ m or less is more preferable, and 30 ⁇ m or less is particularly preferable from the viewpoint of input / output characteristics and electrode production (smoothness of electrode surface etc.).
  • the average particle diameter means a particle diameter (median diameter: d 50 ) at an integrated value of 50% in a particle size distribution (volume basis) by a laser diffraction scattering method.
  • the aqueous binder is not particularly limited as long as it can be electrode-shaped and has sufficient electrochemical stability.
  • a rubber binder resin or an acrylic binder resin can be used.
  • the aqueous binder resin refers to one that can be dispersed in water to form an aqueous emulsion solution.
  • the aqueous binder according to the present embodiment is formed of latex particles, and is preferably dispersed in water and used as an aqueous emulsion solution. That is, the water-based binder according to the present embodiment is preferably formed of latex particles of the water-based binder.
  • the aqueous binder resin can be contained in the negative electrode active material layer without inhibiting the contact between the negative electrode active material, between the conductive support agents, and between the negative electrode active material and the conductive support agent.
  • the rubber-based binder resin examples include styrene-butadiene copolymer rubber and the like.
  • the acrylic binder resin for example, a polymer (homopolymer or homopolymer containing units of acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, acrylic acid salt, or methacrylic acid salt (hereinafter referred to as “acrylic unit”) Copolymers) and the like.
  • acrylic unit a copolymer containing an acryl unit and a styrene unit, a copolymer containing an acryl unit and a silicon unit, and the like can be mentioned.
  • These aqueous binder resins may be used singly or in combination of two or more.
  • styrene-butadiene copolymer rubbers are particularly preferable in terms of excellent binding properties, affinity with an electrolytic solution, cost and electrochemical stability.
  • the content of the water-based binder is preferably 0.01 parts by mass or more and 10.0 parts by mass or less, and 0.05 parts by mass or more, based on 100 parts by mass of the total solid content of the paste for negative electrode production. More preferably, it is 0 parts by mass or less.
  • the balance of the coating property of the paste for negative electrode manufacture, the binding property of a binder, and battery characteristics as the content of an aqueous binder is in the said range is much more excellent.
  • aqueous binder for example, a powdery one is dispersed in an aqueous medium and used as an aqueous emulsion solution.
  • the aqueous medium in which the aqueous binder is dispersed is not particularly limited as long as it can disperse the aqueous binder, but distilled water, ion exchanged water, city water, industrial water, etc. can be used. Among these, distilled water and ion exchange water are preferable.
  • water may be mixed with water such as alcohol and a highly hydrophilic solvent.
  • the styrene-butadiene copolymer rubber is a copolymer containing styrene and 1,3-butadiene as main components.
  • the main component means that the total content of the structural unit derived from styrene and the structural unit derived from 1,3-butadiene in the styrene-butadiene copolymer rubber is the total polymerization unit of the styrene-butadiene copolymer rubber 50% by mass or more.
  • the mass ratio (St / BD) of the structural unit derived from styrene (hereinafter also referred to as St) and the structural unit derived from 1,3-butadiene (hereinafter also referred to as BD) is, for example, 10/90 to 90 /. 10
  • the styrene butadiene copolymer rubber may be copolymerized with monomer components other than styrene and 1,3-butadiene.
  • monomer components other than styrene and 1,3-butadiene For example, conjugated diene-based monomers, unsaturated carboxylic acid monomers, other known copolymerizable monomers, and the like can be mentioned.
  • conjugated diene-based monomer include isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, piperylene and the like.
  • unsaturated carboxylic acid monomers include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid and the like.
  • the manufacturing method of a styrene butadiene copolymer rubber is not specifically limited, It is preferable to manufacture by an emulsion polymerization method.
  • emulsion polymerization When emulsion polymerization is used, it can be obtained as latex particles containing a styrene-butadiene copolymer rubber.
  • Conventionally known methods can be used as the emulsion polymerization. For example, it is produced by emulsion polymerization in water by adding a polymerization initiator, preferably in the presence of an emulsifying agent, of styrene, 1,3-butadiene, and various copolymerizable monomer components described above. Can.
  • the thickener is not particularly limited as long as it improves the coatability of the paste for negative electrode production.
  • the thickener include water-soluble polymers such as cellulose-based water-soluble polymers; polycarboxylic acids; polyethylene oxide; polyvinyl pyrrolidone; polyacrylates such as sodium polyacrylate; These thickeners may be used alone or in combination of two or more. Among these, cellulose-based water-soluble polymers are preferable.
  • the cellulose-based water-soluble polymer is not particularly limited as long as it improves the coatability of the paste for negative electrode production.
  • examples of cellulose-based water-soluble polymers include cellulose-based polymers such as carboxymethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, methylethylhydroxycellulose, methylcellulose and hydroxypropylcellulose, and ammonium salts and alkali metal salts of these cellulose-based polymers It is possible to use one or two or more selected from cellulose-based polymer salts and the like.
  • carboxymethylcellulose and carboxymethylcellulose salt it is preferable to include at least one selected from carboxymethylcellulose and carboxymethylcellulose salt, and one or more selected from carboxymethylcellulose, ammonium salt of carboxymethylcellulose, sodium salt of carboxymethylcellulose and potassium salt of carboxymethylcellulose. More preferably,
  • the degree of etherification of the cellulose-based water-soluble polymer is preferably 0.50 or more and 1.0 or less, and more preferably 0.70 or more and 0.90 or less.
  • the degree of etherification refers to the degree of substitution of a hydroxyl group per anhydroglucose unit in a cellulose-based water-soluble polymer with a substituent to a carboxymethyl group or the like.
  • the weight average molecular weight Mw (in terms of polyethylene glycol) of the cellulose-based water-soluble polymer, which is measured by gel permeation chromatography (GPC), is preferably 100,000 or more, and more preferably 200,000 or more.
  • the storage elastic modulus of the paste for manufacturing a negative electrode according to the present embodiment can be effectively increased when the weight average molecular weight Mw of the cellulose-based water-soluble polymer is not less than the above lower limit value. Moreover, it is preferable that it is 900000 or less, and, as for the weight average molecular weight Mw (polyethylene glycol conversion value) of a cellulose type water-soluble polymer measured by GPC, it is more preferable that it is 800000 or less.
  • the weight average molecular weight Mw of the cellulose-based water-soluble polymer is less than or equal to the above upper limit, the solubility of the cellulose-based water-soluble polymer in the aqueous medium is improved, and the solid content concentration of the paste for negative electrode production can be increased. As a result, the storage elastic modulus of the paste for manufacturing a negative electrode according to this embodiment can be effectively increased.
  • the content of the thickener is preferably 0.01 parts by mass or more and 10.0 parts by mass or less, and preferably 0.05 parts by mass or more, based on 100 parts by mass of the total solid content of the paste for negative electrode production. It is more preferable that it is not more than 0 parts by mass.
  • the balance of the coating property of the paste for negative electrode manufacture, the binding property of a binder, and battery characteristics as the content of a thickener is in the said range is much more excellent.
  • the paste for producing a negative electrode according to this embodiment preferably further includes a conductive aid.
  • the conductive aid is not particularly limited as long as it has electron conductivity and improves the conductivity of the electrode.
  • Examples of the conductive additive according to this embodiment include carbon materials such as acetylene black, ketjen black, carbon black, carbon nanofibers, and graphite having a particle diameter smaller than that of graphite used as an active material. These conductive aids may be used alone or in combination of two or more.
  • the content of the conductive additive is preferably 0.01 parts by mass or more and 10.0 parts by mass or less, and 0.05 parts by mass or more, based on 100 parts by mass of the total solid content of the paste for negative electrode production. It is more preferable that it is not more than 0 parts by mass.
  • the balance of the coating property of the paste for negative electrode manufacture and the binding property of a binder as the content of a conductive support agent is in the said range is much more excellent.
  • the specific surface area by the nitrogen adsorption BET method of the conductive additive is preferably 50 m 2 / g or more and 1000 m 2 / g or less from the viewpoint of the balance between the coatability of the paste for producing a negative electrode and the conductivity of the electrode.
  • Water based medium It does not specifically limit about the aqueous medium which concerns on this embodiment, For example, distilled water, ion-exchange water, city water, industrial water etc. can be used. Among these, distilled water and ion exchange water are preferable. In addition, water may be mixed with water such as alcohol and a highly hydrophilic solvent.
  • the content of the negative electrode active material is preferably 70 parts by mass or more and 99.97 parts by mass or less, when the total content of the solid content of the paste for negative electrode manufacture is 100 parts by mass, in the paste for negative electrode manufacture according to the present embodiment. More preferably, it is 85 parts by mass or more and 99.85 parts by mass or less.
  • the content of the aqueous binder is preferably 0.01 parts by mass or more and 10.0 parts by mass or less, and more preferably 0.05 parts by mass or more and 5.0 parts by mass or less.
  • the content of the thickener is preferably 0.01 parts by mass or more and 10.0 parts by mass or less, and more preferably 0.05 parts by mass or more and 5.0 parts by mass or less.
  • content of a conductive support agent becomes like this.
  • it is 0.01 to 10.0 mass parts, More preferably, it is 0.05 to 5.0 mass parts.
  • the balance of the quality stability of the paste for negative electrode manufacture and the battery characteristic of the battery obtained as the content of each component which comprises the paste for negative electrode manufacture is in the said range is especially excellent.
  • the method for producing a paste for producing a negative electrode according to the present embodiment includes a negative electrode active material, an aqueous binder, a thickener, and an aqueous medium, and further includes, if necessary, a negative electrode for a battery.
  • a powder mixture containing the negative electrode active material and the thickener powder is prepared by dry-mixing the negative electrode active material and the thickener powder in a powder state.
  • the conductive aid may be combined and powder mixed.
  • the dispersibility of the negative electrode active material and the thickener can be enhanced, and in the subsequent steps, the formation of the gel component derived from the thickener can be further suppressed. it can. Thereby, generation
  • a mixer which performs dry mixing it is preferable to use a planetary motion type mixer, and it is more preferable to use a planetary motion type planetary mixer.
  • a planetary motion type mixer means the mixer which has rotation and revolution function as a stirring mechanism.
  • the planetary motion type planetary mixer refers to a mixer having a blade having rotation and revolution functions as a stirring mechanism.
  • the rotation speed of the dry mixing in the dry mixing step (A) is preferably in the range of 0.05 m / sec to 0.55 m / sec, and is in the range of 0.07 m / sec to 0.52 m / sec. It is more preferable that it is inside.
  • the negative electrode active material and the thickener powder are sufficiently mixed while suppressing the scattering of the negative electrode active material and the thickener powder as the rotation speed of the dry mixing in the dry mixing step (A) falls within the above range be able to.
  • the revolving speed of the said dry mixing in dry mixing process (A) exists in the range of 0.01 m / sec or more and 0.20 m / sec or less, and 0.02 m / sec or more and 0.15 m / sec or less It is more preferable to be in the range of The negative electrode active material and the thickener powder are sufficiently mixed while suppressing the scattering of the negative electrode active material and the thickener powder as the revolution speed of the dry mixing in the dry mixing step (A) falls within the above range be able to.
  • the mixing time of the dry mixing in the dry mixing step (A) is not particularly limited, and is, for example, 5 minutes or more and 120 minutes or less, preferably 10 minutes or more and 60 minutes or less.
  • the paste precursor preparation step (B) one or two or more kinds of liquid components selected from an aqueous medium and an aqueous emulsion solution containing an aqueous binder are added to the above mixture obtained in the step (A) for wet mixing
  • the paste precursor is prepared by
  • a mixer which performs wet mixing in the paste precursor preparation process (B) it is preferable to use a planetary motion type mixer, and it is more preferable to use a planetary motion type planetary mixer.
  • a mixer which performs wet mixing in the paste precursor preparation process (B)
  • it is preferable to use a planetary motion type mixer and it is more preferable to use a planetary motion type planetary mixer.
  • the paste precursor preparation step (B) is a two or more step including at least a first solidifying step (B2) and a second solidifying step (B3). Furthermore, if necessary, a blending step (B1) may be performed prior to the first solidifying step (B2).
  • the blending step (B1) is a step of blending the powder mixture with one or more liquid components selected from an aqueous medium and an aqueous emulsion containing a water-based binder.
  • the powder mixture may rise to the edge of the mixer during wet mixing, the wetting of the powder mixture may be uneven, the powder mixture may be scattered during kneading, etc. In the range of
  • the rotation speed of the wet mixing in the blending step (B1) is preferably in the range of 0.10 m / sec to 0.50 m / sec, and in the range of 0.15 m / sec to 0.20 m / sec. It is more preferable that it is inside. If the rotation speed of the wet mixing in the blending step (B1) is within the above range, the powder mixture may rise up to the edge of the mixer during wet mixing, the wetting of the powder mixture may be biased, and the powder The liquid component can be sufficiently mixed with the powder mixture while suppressing the mixture from scattering and the like more effectively at the time of kneading.
  • the revolving speed of the said wet mixing in an adaptation process (B1) exists in the range of 0.03 m / sec or more and 0.06 m / sec or less, and 0.04 m / sec or more and 0.06 m / sec or less It is more preferable to be in the range of If the revolution speed of the wet mixing in the blending step (B1) is within the above range, the powder mixture may rise up to the edge of the mixer during wet mixing, the wetting of the powder mixture may be biased, and the powder The liquid component can be sufficiently mixed with the powder mixture while suppressing the mixture from scattering and the like more effectively at the time of kneading.
  • the mixing time of the said wet mixing in an adaptation process (B1) is not specifically limited, For example, it is preferable that it is 0.5 to 10 minutes, and it is more preferable that it is 2 to 5 minutes.
  • the rotation speed of wet mixing is set higher than in the soaking step (B1), and the powder mixture and the liquid component are It is a process of kneading and obtaining a paste precursor.
  • the solid content concentration of the paste precursor is preferably adjusted to 68% by mass to 77% by mass, and more preferably adjusted to 70% by mass to 74% by mass, It is more preferable to adjust to 71% by mass or more and 72% by mass or less.
  • the aqueous binder to be added in the subsequent paste preparation step (C) for negative electrode production is efficiently adsorbed by the active material and the conductive support agent to which the above-mentioned thickener is adsorbed, and three-dimensional by the interaction between each material Network develops.
  • the adhesion between the current collector layer and the negative electrode active material layer, that is, the peel strength is further improved. it can.
  • the powder mixture containing the active material and the conductive additive can be effectively suppressed from rising up to the edge of the mixer at the time of wet mixing, so that the stable viscosity -The paste for negative electrode manufacture of a mixing ratio can be obtained.
  • the mixing time of the wet mixing in the first solidifying step (B2) is not particularly limited, and is, for example, 5 minutes or more and 60 minutes or less.
  • the solid content concentration of the paste precursor is preferably adjusted to 59% by mass to 66% by mass, and more preferably adjusted to 61% by mass to 64% by mass, It is more preferable to adjust to 62 mass% or more and 63 mass% or less.
  • the solid content concentration By making solid content concentration more than the said lower limit, it can suppress that a solid mixture will be in the state of what is called a lump, and can prepare a uniform paste.
  • the thickener appropriately dispersed in the paste suppresses the movement of the water-based binder to the surface of the negative electrode active material layer in the next coating and drying step. As a result, it is considered that uneven distribution of the aqueous binder on the surface of the negative electrode active material layer can be suppressed.
  • the mixing time of the wet mixing in the second solidifying step (B3) is not particularly limited, and is, for example, 5 minutes or more and 60 minutes or less.
  • the rotation speed (the linear velocity of the blade of the planetary motion mixer) of the wet mixing in the first solidifying step (B2) and the second solidifying step (B3) is 0.10 m / sec or more and 2.0 m / sec or more It is preferable to be in the following range, and it is more preferable to be in the range of 0.20 m / sec or more and 1.2 m / sec or less.
  • the revolution speed (the linear velocity of the blade of the planetary motion mixer) of the above-mentioned wet mixing in the first solidifying step (B2) and the second solidifying step (B3) is 0.01 m / sec or more and 1.0 m or more It is preferable to be in the range of 2 sec or less, and more preferable to be in the range of 0.05 m / sec or more and 0.35 m / sec or less.
  • the paste preparation step (C) for negative electrode production at least one liquid selected from an aqueous solution containing an aqueous medium and an aqueous binder in the paste precursor obtained in the paste precursor preparation step (B)
  • the above-mentioned paste for producing a negative electrode is prepared by further adding components and wet mixing.
  • a mixer which performs wet mixing in the paste preparation process (C) for negative electrode manufacture it is preferable to use a planetary motion type mixer, and it is more preferable to use a planetary motion type planetary mixer.
  • a mixer By using such a mixer, sufficient mixing can be performed while stirring at low speed. Therefore, the dispersibility of each material which comprises the paste for negative electrode manufacture can be improved, suppressing the cutting
  • the obtained paste for producing a negative electrode is further excellent in dispersibility, when such a paste for producing a negative electrode is used, it is possible to obtain a much more uniform negative electrode active material layer. As a result, a battery having even more excellent battery characteristics can be obtained.
  • the rotation speed of the wet mixing (linear velocity of the blade of the planetary motion mixer) in the paste preparation step (C) for producing a negative electrode is not particularly limited, but is, for example, 0.10 m / sec or more and 10.0 m / sec. It is in the following range.
  • the revolution speed of the wet mixing (linear velocity of the blade of the planetary motion mixer) in the paste preparation step (C) for negative electrode production is not particularly limited, but is, for example, 0.02 m / sec or more and 3.0 m or more It is in the range below / sec.
  • the mixing time of the said wet mixing in the paste preparation process (C) for negative electrode manufacture is not specifically limited, For example, they are 5 minutes or more and 60 minutes or less.
  • solid content concentration of the paste for negative electrode manufacture in the paste preparation process (C) for negative electrode manufacture can be adjusted by adjusting the density
  • the method for producing a paste for producing a negative electrode according to the present embodiment may further include the step of degassing step (D): vacuum degassing.
  • degassing step (D) vacuum degassing.
  • the vacuum degassing may be performed by sealing the container or shaft of the mixer to remove air bubbles, or by transferring it to another container.
  • FIG. 1 is a cross-sectional view showing an example of the structure of a battery negative electrode 100 according to an embodiment of the present invention.
  • the battery negative electrode 100 according to the present embodiment is provided on at least one of the current collector layer 101 and the current collector layer 101, and is formed of the solid content of the negative electrode production paste according to the present embodiment.
  • the negative electrode active material layer 103 is formed of the negative electrode active material layer 103.
  • the current collector layer 101 used for manufacturing the battery negative electrode 100 for example, a normal current collector that can be used for a battery can be used.
  • the battery is a lithium ion battery
  • copper, stainless steel, nickel, titanium or an alloy thereof can be used as the negative electrode current collector, and among these, copper is particularly preferable.
  • the shape of the current collector is not particularly limited. For example, a foil-like material having a thickness of 0.001 to 0.5 mm can be used.
  • the thickness and density of the negative electrode active material layer 103 according to the present embodiment are not particularly limited because they are appropriately determined in accordance with the use and the like of the battery, and can be set according to generally known information.
  • the negative electrode manufacturing paste obtained by the method of manufacturing the negative electrode manufacturing paste according to the present embodiment is applied to the current collector layer 101 and dried.
  • a step of forming the negative electrode active material layer 103 on the current collector layer 101 by removing the medium is included.
  • the battery negative electrode 100 having excellent adhesion between the current collector layer 101 and the negative electrode active material layer 103 can be stably obtained.
  • the negative electrode for battery 100 applies the paste for producing a negative electrode according to the present embodiment on the negative electrode current collector layer 101 and dries it, and then the aqueous medium is removed. It can be obtained by forming the negative electrode active material layer 103 thereon.
  • the paste for manufacturing a negative electrode according to the present embodiment may be applied to only one side of the current collector layer 101 or may be applied to both sides. In the case of coating on both sides of the current collector layer 101, one side may be sequentially applied, or both sides may be applied simultaneously. In addition, it may be applied to the surface of the current collector layer 101 continuously or intermittently.
  • the thickness, length, and width of the coating layer can be appropriately determined according to the size of the battery.
  • a commonly known method can be used to dry the applied paste for negative electrode production.
  • hot air, vacuum, infrared, far infrared, electron beam and low temperature air can be used alone or in combination.
  • the drying temperature is, for example, in the range of 30 ° C. or more and 350 ° C. or less.
  • the battery negative electrode 100 according to the present embodiment may be pressed as necessary.
  • a method of pressing generally known methods can be used.
  • a die press method, a calendar press method, etc. may be mentioned.
  • the pressing pressure is not particularly limited, but is, for example, in the range of 0.2 to 3 t / cm 2 .
  • the thickness and density of the battery negative electrode 100 according to the present embodiment are not particularly limited because they are appropriately determined according to the use and the like of the battery, and can be set according to generally known information.
  • FIG. 2 is a cross-sectional view showing an example of the structure of the battery 150 according to the embodiment of the present invention.
  • a battery 150 according to the present embodiment includes at least a positive electrode 120, an electrolyte 110, and a negative electrode 130, and the negative electrode 130 includes the battery negative electrode 100 according to the present embodiment.
  • the battery 150 according to the present embodiment may include a separator as needed.
  • the negative electrode 130 since the negative electrode 130 includes the battery negative electrode 100 according to the present embodiment, powder removal of the negative electrode active material layer when assembling the battery is suppressed, and battery quality and battery The cycle characteristics etc. are good.
  • the battery 150 according to the present embodiment can be manufactured according to a known method.
  • As the electrode for example, a laminate or a wound body can be used.
  • As an exterior body a metal exterior body and an aluminum laminate exterior body can be used suitably.
  • the shape of the battery may be any shape such as coin type, button type, sheet type, cylindrical type, square type and flat type.
  • the positive electrode 120 of the battery can be manufactured by a known manufacturing method.
  • a paste containing at least a positive electrode active material and a binder, and, if necessary, a conductive auxiliary agent and a thickener may be applied to a positive electrode current collector and manufactured using a method such as drying .
  • the positive electrode active material is not particularly limited as long as it is a normal positive electrode active material usable for the positive electrode of the battery.
  • a lithium ion battery for example, a composite oxide of lithium and a transition metal such as lithium nickel composite oxide, lithium cobalt composite oxide, lithium manganese composite oxide, lithium-manganese-nickel composite oxide; TiS 2 , transition metal sulfides such as FeS and MoS 2 ; transition metal oxides such as MnO, V 2 O 5 , V 6 O 13 , TiO 2 , and olivine-type lithium phosphorus oxide.
  • the olivine-type lithium phosphorus oxide is, for example, at least one member of the group consisting of Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg, B, Nb, and Fe. It contains elements, lithium, phosphorus and oxygen. These compounds may be obtained by partially replacing some elements with other elements in order to improve their properties.
  • olivine-type lithium iron phosphorus oxide, lithium cobalt composite oxide, lithium nickel composite oxide, lithium manganese composite oxide, and lithium-manganese-nickel composite oxide are preferable.
  • These positive electrode active materials have large capacity in addition to high action potential and large energy density.
  • the positive electrode active material may be used singly or in combination of two or more.
  • the binder resin used for the positive electrode is appropriately selected according to the application.
  • a fluorine-based binder resin that can be dissolved in a solvent, an aqueous binder that can be dispersed in water, or the like can be used.
  • the fluorine-based binder resin is not particularly limited as long as it can be formed into an electrode and has sufficient electrochemical stability, and examples thereof include polyvinylidene fluoride resins and fluororubbers. These fluorine-based binder resins may be used alone or in combination of two or more. Among these, polyvinylidene fluoride resins are preferable.
  • the fluorine-based binder resin can be used, for example, by dissolving it in a solvent such as N-methyl-pyrrolidone (NMP).
  • NMP N-methyl-pyrrolidone
  • the aqueous binder resin, the thickener, and the conductive additive the same materials as those constituting the paste for producing a negative electrode according to the present embodiment can be used.
  • the positive electrode current collector aluminum, stainless steel, nickel, titanium or an alloy thereof can be used. Among these, aluminum is particularly preferable.
  • any known lithium salt can be used as the electrolyte in the electrolytic solution of the battery, and it may be selected according to the type of active material.
  • LiClO 4, LiBF 6, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiB 10 Cl 10, LiAlCl 4, LiCl, LiBr, LiB (C 2 H 5) 4, CF 3 SO 3 Li, CH 3 SO 3 Li, LiCF 3 SO 3 , LiC 4 F 9 SO 3 , Li (CF 3 SO 2 ) 2 N, lithium lower fatty acid carboxylate and the like can be mentioned.
  • the solvent for dissolving the electrolyte is not particularly limited as long as it is generally used as a liquid component for dissolving the electrolyte, and ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), vinylene carbonate (VC) and other carbonates; ⁇ -butyrolactone, ⁇ -valerolactone and other lactones; trimethoxymethane, 1,2-dimethoxyethane Ethers such as diethyl ether, 2-ethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, etc.
  • Sulfoxides such as dimethylsulfoxide etc.
  • Oxolanes such as 1,3-dioxolane, 4-methyl-1,3-dioxolanekinds of nitrogen; Nitrogenous compounds such as acetonitrile, nitromethane, formamide, dimethylformamide, etc .; Organic acid esters such as methyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl propionate, ethyl propionate; phosphoric acid triesters and diglymes; Triligmes; sulfolanes such as sulfolane and methyl sulfolane; oxazolidinones such as 3-methyl-2-oxazolidinone; and sultones such as 1,3-propane sultone, 1,4-butane sultone and naphtha sultone. These may be used singly or in combination of two or more.
  • a porous separator As a separator, a porous separator is mentioned, for example.
  • the form of the separator includes a membrane, a film, a non-woven fabric and the like.
  • the porous separator include polyolefin-based porous separators such as polypropylene and polyethylene; porous separators formed of polyvinylidene fluoride, polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride hexafluoropropylene copolymer, etc. Can be mentioned.
  • Example 1 Preparation of paste for aqueous negative electrode production>
  • MAC series of Sun Rose registered trademark
  • Mw weight average molecular weight
  • a rotation speed of 0.26 m / sec a rotation speed of 0.08 m / sec
  • a temperature of 20 ° C. a powder mixture.
  • the rotation speed and revolution speed are linear speeds of blades of a planetary motion type planetary mixer.
  • the average particle diameter d 50 is measured by MT 3000, manufactured by Microtrac, and the specific surface area is determined by nitrogen adsorption BET method using Quanta Sorb manufactured by Quantachrome Corporation.
  • graphite whose surface was coated with amorphous carbon was produced as follows. Natural graphite having an average particle diameter d 50 of 16 ⁇ m and a specific surface area of 3.4 m 2 / g was used as a core material. 99.0 parts by mass of this natural graphite powder and 1.0 parts by mass of coal-based pitch powder were mixed in a solid phase by simple mixing using a V blender. The obtained mixed powder was placed in a graphite crucible and heat-treated at 1300 ° C. for 1 hour in a nitrogen stream to obtain graphite whose surface was coated with amorphous carbon.
  • the obtained paste for negative electrode production was applied to both sides of a copper foil as a current collector layer using a die coater, and dried. Then, the obtained electrode was pressed to obtain a negative electrode.
  • Viscosity measurement of paste for negative electrode production The viscosity of the paste for negative electrode production was measured under the conditions of 25 ° C. and a shear rate of 3.4 s ⁇ 1 using a B-type viscometer (rotation viscometer manufactured by Brookfield Co., Ltd.) .
  • the peeling strength of the obtained negative electrode was measured by the following procedure. The negative electrode was cut over a width of 20 mm and a length of 10 cm, and one side of the negative electrode was attached to a plate on which a double-sided tape was applied. Then, the plate was fixed, and the negative electrode was peeled in the direction of 90 ° at a speed of 100 mm / min. The peel strength (mN / mm) at that time was measured three times, and the average value was taken as the peel strength.
  • Example 2 to 15, Comparative Examples 1 to 6 Example except that the solid concentration of the first solidifying step (B2) and the second solidifying step (B3) and the mixing time were changed to the values shown in Table 1
  • the paste for water system negative electrode manufacture was prepared similarly to 1, respectively, and each evaluation was performed, respectively. The obtained results are shown in Table 1.

Abstract

This method for producing a paste for negative electrode production is a production method of a paste for the production of a negative electrode for batteries, said paste containing a negative electrode active material, an aqueous binder, a thickening agent and an aqueous medium. This method for producing a paste for negative electrode production is carried out by a plurality of steps including at least: a first thick kneading step wherein a plurality of powder materials including at least the negative electrode active material and the thickening agent are dry mixed in a powder state, and subsequently an aqueous solution containing the aqueous medium and the aqueous binder is added to and wet mixed with the mixture; and a second thick kneading step. The solid content concentration in the first thick kneading step is from 68% by mass to 79% by mass (inclusive); and the solid content concentration in the second thick kneading step is from 59% by mass to 66% by mass (inclusive).

Description

負極製造用ペーストの製造方法、電池用負極電極、電池および電池用負極電極の製造方法Method for producing paste for producing negative electrode, negative electrode for battery, method for producing battery and negative electrode for battery
　本発明は、負極製造用ペーストの製造方法、電池用負極電極、電池および電池用負極電極の製造方法に関する。 The present invention relates to a method for producing a paste for producing a negative electrode, a battery negative electrode, a battery and a method for producing a battery negative electrode.
　電池に用いられる負極電極は、一般的に、負極活物質層と集電体層から主に構成されている。負極活物質層は、例えば、負極活物質、増粘剤および水系バインダー等を含む負極製造用ペーストを金属箔等の集電体層表面に塗布して乾燥することにより得ることができる。 Generally, a negative electrode used in a battery is mainly composed of a negative electrode active material layer and a current collector layer. The negative electrode active material layer can be obtained, for example, by applying a negative electrode production paste containing a negative electrode active material, a thickener, an aqueous binder and the like on the surface of a current collector layer such as metal foil and drying.
　電池用負極の製造方法としては、例えば、特許文献１に記載の方法が挙げられる。 As a manufacturing method of the negative electrode for batteries, the method of patent document 1 is mentioned, for example.
　特許文献１（特許第５３９６９８９号公報）には、炭素粉末１ａおよびＣＭＣ粉末１ｂを投入し、粉体のみの状態で混合して粉体混合物１を生成した後、ペーストの粘度、粒度および剥離強度との各相関に基づいて、分散媒の投入量や固練り時間を決定し、粗練り工程と固練り工程の二段階に分けて、分散媒である水を投入する、リチウムイオン二次電池の製造に用いられるペーストの製造法が記載されている。 In Patent Document 1 (Japanese Patent No. 5396989), the carbon powder 1a and the CMC powder 1b are introduced, and mixed in a powder-only state to form a powder mixture 1, and then the viscosity, particle size and peel strength of the paste are obtained. The amount of dispersion medium input and the solidifying time are determined on the basis of each correlation with the above, and divided into two steps of the coarse mixing process and the solid mixing process, and the water as the dispersion medium is added, lithium ion secondary battery A method of producing the paste used for production is described.
特許第５３９６９８９号公報Patent No. 5396989
　本発明者らの検討によれば、従来の製造方法により得られる電池用負極電極は剥離強度が低い場合があり、集電体層と負極活物質層との接着性に改善の余地があることが明らかになった。
　電池用負極電極の剥離強度が低い場合、電極や電池の生産性が低下したり、電池を組み立てる工程において負極活物質層の粉落ちが起こり、その結果、電池の品質劣化や電池のサイクル特性等に不具合が起きたりする懸念がある。 According to studies by the present inventors, the negative electrode for a battery obtained by the conventional manufacturing method may have low peel strength, and there is room for improvement in the adhesion between the current collector layer and the negative electrode active material layer. It became clear.
When the peel strength of the negative electrode for battery is low, productivity of the electrode or battery is reduced, and powdering of the negative electrode active material layer occurs in the process of assembling the battery. As a result, battery quality deterioration, battery cycle characteristics, etc. There is a concern that problems may occur in
　また、特許文献１（特許第５３９６９８９号公報）には、具体的に各工程での固形分濃度を定めた記載はなく、ペーストの粘度、粒度および剥離強度との各相関が求められなければ、固形分濃度を算出することが難しいという問題があった。また、固形分濃度が高すぎた場合、ミキサーを用いてペーストを攪拌混合する工程において、紛体混合物が湿式混合時に混合機のふちにせり上がってくるため、得られたペーストが不均一となり、その結果、上記負極製造用ペーストを塗布・乾燥して作製した負極電極の粘度や剥離強度が一定にならない問題や、上記負極電極を用いて作製した電池の性能が一定にならないという問題があった。 In addition, Patent Document 1 (Japanese Patent No. 5396989) does not specifically describe the solid content concentration in each step, and if the correlation with the viscosity, particle size and peel strength of the paste is not required, There is a problem that it is difficult to calculate the solid concentration. Also, if the solid concentration is too high, in the process of stirring and mixing the paste using a mixer, the powder mixture rises up to the edge of the mixer during wet mixing, so the obtained paste becomes uneven, and As a result, there is a problem that the viscosity and peel strength of the negative electrode produced by applying and drying the above paste for negative electrode are not constant, and the performance of a battery produced using the above negative electrode is not constant.
　本発明は上記事情に鑑みてなされたものであり、集電体層と負極活物質層との接着性に優れた電池用負極電極を安定的に得ることが可能な負極製造用ペーストの製造方法を提供するものである。 The present invention has been made in view of the above circumstances, and a method for producing a paste for producing a negative electrode capable of stably obtaining a negative electrode for a battery excellent in adhesion between the current collector layer and the negative electrode active material layer. To provide
　本発明者らは上記課題を達成すべく鋭意検討を重ねた。その結果、乾式混合した負極活物質および増粘剤を少なくとも含む混合物に、水系媒体および水系バインダーを含むエマルジョン水溶液から選択される一種または二種以上の液体成分を添加して湿式混合する工程を、第１の固練り工程と第２の固練り工程の二段階とした上で、上記第１の固練り工程における固形分濃度を６８質量％以上７９質量％以下に設定し、上記第２の固練り工程における固形分濃度を５９質量％以上６６質量％以下に設定する負極製造用ペーストの製造方法を用いることにより、集電体層と負極活物質層との接着性に優れた電池用負極電極を安定的に得ることができることを見出して本発明を完成するに至った。 The present inventors diligently studied to achieve the above object. As a result, one or two or more types of liquid components selected from an aqueous solution and an aqueous emulsion solution containing an aqueous binder are added to a mixture containing at least a dry mixed negative electrode active material and a thickener, and wet mixed, The solid content concentration in the first solidifying step is set to 68% by mass or more and 79% by mass or lower after the first solidifying step and the second solidifying step are performed in two steps. A negative electrode for a battery having excellent adhesiveness between the current collector layer and the negative electrode active material layer by using the method for producing a negative electrode production paste in which the solid content concentration in the kneading step is set to 59 mass% to 66 mass%. It came to complete the present invention by finding that it could obtain stably.
　すなわち、本発明によれば、
　負極活物質および増粘剤を少なくとも含む複数の粉末状物質を紛体状態で乾式混合することにより、上記負極活物質および上記増粘剤を少なくとも含む混合物を調製する工程（Ａ）と、
　上記混合物中に、水系媒体および水系バインダーを含むエマルジョン水溶液から選択される一種または二種以上の液体成分を添加して湿式混合することにより、ペースト前駆体を調製する工程（Ｂ）と、
　上記ペースト前駆体中に、上記水系媒体および上記水系バインダーを含むエマルジョン水溶液から選択される一種または二種以上の液体成分をさらに添加して湿式混合することにより、負極製造用ペーストを調製する工程（Ｃ）と、
を含む、負極製造用ペーストの製造方法であって、
　上記工程（Ｂ）は、第１の固練り工程（Ｂ２）と第２の固練り工程（Ｂ３）とを少なくとも含み、
　上記第１の固練り工程（Ｂ２）における固形分濃度が６８質量％以上７９質量％以下であり、上記第２の固練り工程（Ｂ３）における固形分濃度が５９質量％以上６６質量％以下である、負極製造用ペーストの製造方法が提供される。 That is, according to the present invention,
Preparing a mixture containing at least the negative electrode active material and the thickener by dry-mixing a plurality of powdery materials containing at least a negative electrode active material and a thickener in a powder state;
Preparing a paste precursor by adding one or two or more kinds of liquid components selected from an aqueous solution of an aqueous medium and an aqueous binder to the mixture and wet mixing them, and (B)
A step of preparing a paste for negative electrode production by further adding one or two or more types of liquid components selected from the aqueous solution and the aqueous emulsion containing the aqueous binder to the paste precursor and wet mixing C) and
A method for producing a paste for producing a negative electrode, comprising
The step (B) includes at least a first solidifying step (B2) and a second solidifying step (B3),
The solid content concentration in the first solidifying step (B2) is 68% by mass to 79% by mass, and the solid concentration in the second solidifying step (B3) is 59% by mass to 66% by mass A method for producing a paste for producing a negative electrode is provided.
　また、本発明者らは、上記の負極製造用ペーストの製造方法を用いることにより、上記負極製造用ペーストの粘度を一定範囲に制御することができ、その結果、作製した負極製造用ペーストを用いて引き続き行う、負極製造用ペーストを集電体層に塗工して乾燥し、上記水系媒体を除去することによって、上記集電体層上に上記負極活物質層を形成する工程において、安定的な塗工制御ができることを見出した。 Moreover, the present inventors can control the viscosity of the paste for producing a negative electrode within a certain range by using the above-described method for producing a paste for producing a negative electrode, and as a result, using the produced paste for producing a negative electrode The step of continuously forming the negative electrode active material layer on the current collector layer by applying the negative electrode production paste to the current collector layer and drying it, and removing the aqueous medium, is stable. Was found to be able to control the
　本発明によれば、
　本発明の負極製造用ペーストの製造方法により得られた負極製造用ペーストを集電体層に塗工して乾燥し、上記水系媒体を除去することによって、上記集電体層上に上記負極活物質層を形成する工程を含む電池用負極電極の製造方法が提供される。 According to the invention
The paste for producing a negative electrode obtained by the method for producing a paste for producing a negative electrode according to the present invention is applied to a current collector layer and dried, and the aqueous medium is removed to obtain the above-mentioned negative electrode active on the current collector layer. A method of manufacturing a battery negative electrode including the step of forming a material layer is provided.
　また、本発明によれば、
　集電体層と、
　上記集電体層の少なくとも一方の面に設けられ、かつ、本発明の負極製造用ペーストの製造方法により得られた負極製造用ペーストの固形分により形成された負極活物質層と、を含む電池用負極電極が提供される。 Moreover, according to the present invention,
A current collector layer,
A battery comprising: a negative electrode active material layer provided on at least one surface of the current collector layer and formed of the solid content of the negative electrode production paste obtained by the method for producing a negative electrode production paste of the present invention A negative electrode is provided.
　また、本発明によれば、
　正極と、電解質と、負極とを少なくとも備えた電池であって、
　上記負極が本発明の電池用負極電極を含む電池が提供される。 Moreover, according to the present invention,
A battery comprising at least a positive electrode, an electrolyte and a negative electrode,
There is provided a battery including the above-described negative electrode for a battery according to the present invention.
　本発明によれば、集電体層と負極活物質層との接着性に優れた電池用負極電極を安定的に得ることが可能な負極製造用ペーストを提供することができる。 ADVANTAGE OF THE INVENTION According to this invention, the paste for negative electrode manufacture which can obtain stably the negative electrode for batteries excellent in the adhesiveness of a collector layer and a negative electrode active material layer can be provided.
　上述した目的、およびその他の目的、特徴および利点は、以下に述べる好適な実施の形態、およびそれに付随する以下の図面によってさらに明らかになる。 The objects described above, and other objects, features and advantages will become more apparent from the preferred embodiments described below and the following drawings associated therewith.
本発明に係る実施形態の電池用負極電極の構造の一例を示す断面図である。It is sectional drawing which shows an example of the structure of the negative electrode for batteries of embodiment which concerns on this invention. 本発明に係る実施形態の電池の構造の一例を示す断面図である。It is sectional drawing which shows an example of the structure of the battery of embodiment which concerns on this invention.
　以下に、本発明の実施形態について、図面を用いて説明する。なお、すべての図面において、同様な構成要素には同様の符号を付し、適宜説明を省略する。また、図において各構成要素は本発明が理解できる程度の形状、大きさおよび配置関係を概略的に示したものであり、実寸とは異なっている。
　なお、本実施形態では特に断りがなければ、負極活物質を含む層を負極活物質層と呼び、集電体層上に負極活物質層を形成させたものを電極と呼ぶ。また、本実施形態では数値範囲の「Ａ～Ｂ」は特に断りがなければ、Ａ以上Ｂ以下を表す。 Hereinafter, embodiments of the present invention will be described using the drawings. In all the drawings, similar components are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. Further, in the drawings, each component schematically shows the shape, size and arrangement relationship to the extent that the present invention can be understood, and is different from the actual size.
In the present embodiment, unless otherwise specified, a layer containing a negative electrode active material is called a negative electrode active material layer, and a layer in which a negative electrode active material layer is formed on a current collector layer is called an electrode. Further, in the present embodiment, “A to B” in the numerical value range represent A or more and B or less unless otherwise specified.
＜負極製造用ペーストの製造方法＞
　本実施形態に係る負極製造用ペーストの製造方法は、負極活物質と、水系バインダーと、増粘剤と、水系媒体と、を含む電池用の負極製造用ペーストの製造方法であって、
　負極活物質および増粘剤を少なくとも含む複数の粉末状物質を紛体状態で乾式混合することにより、上記負極活物質および上記増粘剤を少なくとも含む混合物を調製する工程（Ａ）と、
　上記混合物中に、水系媒体および水系バインダーを含むエマルジョン水溶液から選択される一種または二種以上の液体成分を添加して湿式混合することにより、ペースト前駆体を調製する工程（Ｂ）と、
　上記ペースト前駆体中に、上記水系媒体および上記水系バインダーを含むエマルジョン水溶液から選択される一種または二種以上の液体成分をさらに添加して湿式混合することにより、上記負極製造用ペーストを調製する工程（Ｃ）と、を含み、
　上記工程（Ｂ）は、第１の固練り工程（Ｂ２）と第２の固練り工程（Ｂ３）とを少なくとも含み、
　上記第１の固練り工程（Ｂ２）における固形分濃度が６８質量％以上７９質量％以下であり、上記第２の固練り工程（Ｂ３）における固形分濃度が５９質量％以上６６質量％以下である、負極製造用ペーストの製造方法である。
　ここで、本実施形態に係る負極製造用ペーストにおいて、増粘剤は負極製造用ペースト中に溶解しており、粉末状態ではない。
　また、本実施形態に係る電池は、例えばリチウムイオン一次電池またはリチウムイオン二次電池であり、好ましくはリチウムイオン二次電池である。 <Method of producing paste for producing negative electrode>
The method for producing a paste for producing a negative electrode according to the present embodiment is a method for producing a paste for producing a negative electrode for a battery, which comprises a negative electrode active material, an aqueous binder, a thickener, and an aqueous medium.
Preparing a mixture containing at least the negative electrode active material and the thickener by dry-mixing a plurality of powdery materials containing at least a negative electrode active material and a thickener in a powder state;
Preparing a paste precursor by adding one or two or more kinds of liquid components selected from an aqueous solution of an aqueous medium and an aqueous binder to the mixture and wet mixing them, and (B)
A step of preparing the paste for producing a negative electrode by further adding one or two or more kinds of liquid components selected from the aqueous medium and the aqueous emulsion containing the aqueous binder to the paste precursor and wet mixing them. And (C),
The step (B) includes at least a first solidifying step (B2) and a second solidifying step (B3),
The solid content concentration in the first solidifying step (B2) is 68% by mass to 79% by mass, and the solid concentration in the second solidifying step (B3) is 59% by mass to 66% by mass This is a method for producing a paste for producing a negative electrode.
Here, in the paste for manufacturing a negative electrode according to the present embodiment, the thickener is dissolved in the paste for manufacturing a negative electrode and is not in a powder state.
The battery according to the present embodiment is, for example, a lithium ion primary battery or a lithium ion secondary battery, preferably a lithium ion secondary battery.
　前述したように、本発明者らの検討によれば、従来の製造方法により得られる電池用負極電極は剥離強度が低い場合があり、集電体層と負極活物質層との接着性に改善の余地があることが明らかになった。
　電池用負極電極の剥離強度が低い場合、電極や電池の生産性が低下したり、電池を組み立てる工程において負極活物質層の粉落ちが起こり、その結果、電池の品質劣化や電池のサイクル特性等に不具合が起きたりする懸念がある。 As described above, according to the study of the present inventors, the negative electrode for a battery obtained by the conventional manufacturing method may have low peel strength in some cases, and the adhesion between the current collector layer and the negative electrode active material layer is improved. It became clear that there was room for
When the peel strength of the negative electrode for battery is low, productivity of the electrode or battery is reduced, and powdering of the negative electrode active material layer occurs in the process of assembling the battery. As a result, battery quality deterioration, battery cycle characteristics, etc. There is a concern that problems may occur in
　本発明者らは上記課題を達成すべく鋭意検討を重ねた。その結果、負極製造用ペーストの前駆体製造工程を第１の固練り工程（Ｂ２）と第２の固練り工程（Ｂ３）の二段階以上とした上で、上記第１の固練り工程（Ｂ２）における固形分濃度を６８質量％以上７９質量％以下に設定し、上記第２の固練り工程（Ｂ３）における固形分濃度を５９質量％以上６６質量％以下に設定する負極製造用ペーストの製造方法を用いることにより、集電体層と負極活物質層との接着性に優れた電池用負極電極を安定的に得ることができることを見出して本発明を完成するに至った。
　ここで、上記第１の固練り工程（Ｂ２）における固形分濃度が６８質量％以上７９質量％以下であり、上記第２の固練り工程（Ｂ３）における固形分濃度が５９質量％以上６６質量％以下である負極製造用ペーストの製造方法を用いることにより、集電体層と負極活物質層との接着性に優れた電池用負極電極を安定的に得ることができる理由は必ずしも明らかではないが、以下の理由が考えられる。
　まず、固形分濃度が６８質量％以上７９質量％以下の状態で上記第１の固練り工程（Ｂ２）を行うことで、活物質や導電助剤に一定量の増粘剤が吸着すると考えられる。これにより、水系媒体中への増粘剤の過剰な分散が抑制される。
　活物質や導電助剤は、引き続き行う上記第２の固練り工程（Ｂ３）において、固形分濃度を５９質量％以上６６質量％以下となるように混合することで、上記の第１の固練り工程（Ｂ２）で吸着した増粘剤を表面に吸着したまま、水系媒体中へ分散すると考えられる。一方、上記の第１の固練り工程（Ｂ２）で活物質や導電助剤に吸着しなかった残りの増粘剤も水系媒体中へ分散する。
　こうして得られた負極製造用ペースト前駆体中では、活物質や導電助剤の多くは、表面に水系バインダーとの吸着性に優れた増粘剤が吸着した集合体として存在している。このため、引き続き行う、負極製造用ペーストの調製工程（Ｃ）で水系バインダーを添加し、湿式混合した際に、上記集合体に効率よく水系バインダーが吸着し、各材料間の相互作用による３次元的なネットワークが発達するものと考えられる。さらに、活物質や導電助剤に吸着しなかった残りの増粘剤は、水系媒体中へ適度に分散している。このため、引き続き行う、負極製造用ペーストを集電体層に塗工して乾燥し、さらに上記水系媒体を除去して、上記集電体層上に上記負極活物質層を形成する工程において、上記のペースト中に分散した増粘剤が、乾燥時の水系バインダーの負極活物質層表面への移動を抑え、その結果、水系バインダーが負極活物質層の表面に偏在してしまうことを抑制できると考えられる。
　そして、水系バインダーの負極活物質層への表面偏在が抑制された結果、集電体層と負極活物質層との界面における水系バインダーの量を増やすことができ、集電体層と負極活物質層との接着性、すなわち剥離強度を向上させることができると考えられる。 The present inventors diligently studied to achieve the above object. As a result, after the precursor production process of the paste for negative electrode production is made into two or more steps of the first solidifying process (B2) and the second solidifying process (B3), the first solidifying process (B2) is performed. Manufacturing the paste for negative electrode manufacture which sets the solid content concentration in 68) to 79 mass% and sets the solid concentration in the said 2nd solidifying process (B3) to 59 mass% to 66 mass%. By using the method, it has been found that the battery negative electrode having excellent adhesion between the current collector layer and the negative electrode active material layer can be stably obtained, and the present invention has been completed.
Here, the solid content concentration in the first solidifying step (B2) is 68% by mass to 79% by mass, and the solid concentration in the second solidifying step (B3) is 59% by mass to 66%. It is not always clear why the battery negative electrode having excellent adhesion between the current collector layer and the negative electrode active material layer can be stably obtained by using the method for producing a negative electrode production paste having% or less. However, the following reasons can be considered.
First, it is considered that by performing the first solidifying step (B2) in a state where the solid content concentration is 68% by mass to 79% by mass, a certain amount of thickener is adsorbed to the active material and the conductive additive. . Thereby, excessive dispersion of the thickener in the aqueous medium is suppressed.
The active material and the conductive auxiliary agent are mixed in the subsequent second solidifying step (B3) so that the solid content concentration is 59% by mass or more and 66% by mass or less, the first solidifying step described above It is considered that the thickener adsorbed in the step (B2) is dispersed in the aqueous medium while being adsorbed on the surface. On the other hand, the remaining thickener which is not adsorbed to the active material and the conductive auxiliary agent in the first solidifying step (B2) is also dispersed in the aqueous medium.
In the paste precursor for producing a negative electrode thus obtained, most of the active material and the conductive additive are present on the surface as an aggregate in which a thickener having excellent adsorptivity with a water-based binder is adsorbed. Therefore, when the aqueous binder is added and wet mixed in the subsequent step of preparing the paste for negative electrode production paste and wet mixed, the aqueous binder is efficiently adsorbed to the above aggregate, and the three-dimensional by the interaction between the respective materials Network is considered to develop. Furthermore, the remaining thickener which has not been adsorbed to the active material or the conductive aid is appropriately dispersed in the aqueous medium. Therefore, in the subsequent step, the paste for manufacturing a negative electrode is applied to the current collector layer and dried, and then the aqueous medium is removed to form the negative electrode active material layer on the current collector layer, The thickener dispersed in the paste suppresses the movement of the water-based binder to the surface of the negative electrode active material layer during drying, and as a result, uneven distribution of the water-based binder on the surface of the negative electrode active material layer can be suppressed it is conceivable that.
And as a result of the uneven distribution of the surface of the aqueous binder in the negative electrode active material layer being suppressed, the amount of the aqueous binder at the interface between the current collector layer and the negative electrode active material layer can be increased. It is believed that adhesion to the layer, ie peel strength, can be improved.
　すなわち、本実施形態に係る負極製造用ペーストの製造方法によれば、上記第１の固練り工程（Ｂ２）における固形分濃度が６８質量％以上７９質量％以下であり、上記第２の固練り工程（Ｂ３）における固形分濃度が５９質量％以上６６質量％以下である、負極製造用ペーストの製造方法を用いることにより、水系バインダーの負極活物質層表面への偏在を抑制でき、集電体層と負極活物質層との接着性、すなわち剥離強度を向上させることができる。
　以上から、本実施形態によれば、集電体層と負極活物質層との接着性に優れた電池用負極電極を安定的に得ることが可能な負極製造用ペーストを提供することができる。 That is, according to the method for producing a paste for producing a negative electrode according to the present embodiment, the solid content concentration in the first solidifying step (B2) is 68% by mass to 79% by mass, and the second solidifying By using the method for producing a paste for producing a negative electrode having a solid content concentration of 59% by mass to 66% by mass in the step (B3), uneven distribution of the aqueous binder on the surface of the negative electrode active material layer can be suppressed. The adhesion between the layer and the negative electrode active material layer, that is, the peel strength can be improved.
As mentioned above, according to this embodiment, the paste for negative electrode manufacture which can obtain stably the negative electrode for batteries excellent in the adhesiveness of a collector layer and a negative electrode active material layer can be provided.
　本実施形態に係る負極製造用ペーストの製造工程のうち、第１の固練り工程（Ｂ２）における固形分濃度の下限は６８質量％であるが、好ましくは７０質量％以上、より好ましくは７１質量％以上である。
　本実施形態に係る負極製造用ペーストの製造方法において、第１の固練り工程（Ｂ２）における固形分濃度を上記下限値以上とすることにより、活物質や導電助剤に一定量の増粘剤が吸着することができるため、水系媒体中への増粘剤の過剰な分散が抑制される。活物質や導電助剤の多くは、引き続き行う上記第２の固練り工程（Ｂ３）においても、増粘剤を表面に吸着した集合体の状態のまま、水系媒体中へ分散すると考えられる。増粘剤は、活物質や導電助剤そのものよりも水系バインダーとの吸着性に優れているため、上記集合体に効率よく水系バインダーが吸着し、各材料間の相互作用による３次元的なネットワークが発達するものと考えられる。 The lower limit of the solid content concentration in the first step of solidifying (B2) in the process of producing the paste for producing a negative electrode according to this embodiment is 68 mass%, preferably 70 mass% or more, more preferably 71 mass % Or more.
In the method for producing a paste for producing a negative electrode according to the present embodiment, the solid content concentration in the first solidifying step (B2) is set to the above lower limit value or more to obtain a constant amount of thickener for the active material and the conductive additive. Can be adsorbed, thereby suppressing excessive dispersion of the thickener in the aqueous medium. Many of the active material and the conductive auxiliary agent are considered to be dispersed in the aqueous medium in the state of an aggregate in which the thickener is adsorbed on the surface also in the above-mentioned second solidifying step (B3). Since the thickener has better adsorptivity with the aqueous binder than the active material and the conductive auxiliary itself, the aqueous binder is efficiently adsorbed to the above-mentioned aggregate, and a three-dimensional network by interaction between each material Is considered to develop.
　本実施形態に係る負極製造用ペーストの製造工程のうち、第１の固練り工程（Ｂ２）における固形分濃度の上限は７９質量％以下であるが、好ましくは７７質量％以下、より好ましくは７４質量％以下、さらに好ましくは７２質量％以下である。
　本実施形態に係る負極製造用ペーストの製造方法において、第１の固練り工程（Ｂ２）における固形分濃度を上記上限値以下とすることにより、活物質や導電助剤を含む紛体混合物が湿式混合時に混合機のふちにせり上がってくることを効果的に抑制できるため、安定した粘度・混合比の負極製造用ペーストを得ることができる。 The upper limit of the solid content concentration in the first solidifying step (B2) in the process of producing the paste for producing a negative electrode according to the present embodiment is 79% by mass or less, preferably 77% by mass or less, more preferably 74 It is at most mass%, more preferably at most 72 mass%.
In the method for producing a paste for producing a negative electrode according to the present embodiment, the powder mixture containing the active material and the conductive additive is wet mixed by setting the solid concentration in the first solidifying step (B2) to the upper limit value or less. Sometimes, it is possible to effectively suppress the rising of the edge of the mixer, so it is possible to obtain a paste for producing a negative electrode with a stable viscosity and mixing ratio.
　本実施形態に係る負極製造用ペーストの製造工程のうち、第２の固練り工程（Ｂ３）における固形分濃度の下限は５９質量％であるが、好ましくは６１質量％以上、より好ましくは６２質量％以上である。
　本実施形態に係る負極製造用ペーストの製造方法において、第２の固練り工程（Ｂ３）における固形分濃度を上記下限値以上とすることにより、固形混合物が所謂ダマの状態になるのを抑制し、均一なペーストを作製することができる。
　本実施形態に係る負極製造用ペーストの製造工程のうち、第２の固練り工程（Ｂ３）における固形分濃度の上限は６６質量％以下であるが、好ましくは６４質量％以下、より好ましくは６３質量％以下である。 The lower limit of the solid content concentration in the second solidifying step (B3) in the process of producing the paste for producing a negative electrode according to this embodiment is 59% by mass, preferably 61% by mass or more, more preferably 62% % Or more.
In the method for producing a paste for producing a negative electrode according to the present embodiment, the solid content concentration in the second solidifying step (B3) is set to the above lower limit value or more to suppress the solid mixture from becoming a so-called lump state. , Uniform paste can be produced.
The upper limit of the solid content concentration in the second solidifying step (B3) in the process of producing the paste for producing a negative electrode according to the present embodiment is 66 mass% or less, preferably 64 mass% or less, more preferably 63 It is less than mass%.
　本実施形態に係る負極製造用ペーストの製造方法において、第２の固練り工程（Ｂ３）における固形分濃度を上記上限値以下とすることにより、上記の第１の固練り工程（Ｂ２）で活物質や導電助剤に吸着しなかった残りの増粘剤を均一に水系媒体中へ分散することができると考えられる。これにより、引き続き行う、負極製造用ペーストを集電体層に塗工して乾燥し、さらに上記水系媒体を除去して、上記集電体層上に上記負極活物質層を形成する工程において、上記のペースト中に分散した増粘剤が、乾燥時の水系バインダーの負極活物質層表面への移動を抑え、その結果、水系バインダーが負極活物質層の表面に偏在してしまうことを抑制できると考えられる。 In the method for producing a paste for producing a negative electrode according to the present embodiment, the solid content concentration in the second solidifying step (B3) is set to the above upper limit value or less to activate in the first solidifying step (B2). It is considered that the remaining thickener which is not adsorbed to the substance or the conductive aid can be uniformly dispersed in the aqueous medium. Thereby, the paste for manufacturing a negative electrode is applied to the current collector layer and dried, and then the aqueous medium is removed to form the negative electrode active material layer on the current collector layer, The thickener dispersed in the paste suppresses the movement of the water-based binder to the surface of the negative electrode active material layer during drying, and as a result, uneven distribution of the water-based binder on the surface of the negative electrode active material layer can be suppressed it is conceivable that.
　本実施形態に係る負極製造用ペーストのｐＨは、負極製造用ペーストの分散安定性を良好にする観点から、例えば６．０以上８．０以下であり、好ましくは６．５以上７．５以下であり、より好ましくは６．８以上７．２以下である。
　本実施形態に係る負極製造用ペーストのｐＨの調整方法はとくに限定はされないが、例えば、負極製造用ペーストを構成する各材料の配合比率や、負極製造用ペーストを構成する各材料の種類等を調整することによって調整することができる。 The pH of the paste for manufacturing a negative electrode according to the present embodiment is, for example, 6.0 or more and 8.0 or less, preferably 6.5 or more and 7.5 or less, from the viewpoint of improving the dispersion stability of the paste for manufacturing a negative electrode. More preferably, they are 6.8 or more and 7.2 or less.
The method of adjusting the pH of the paste for negative electrode production according to the present embodiment is not particularly limited, but, for example, the blending ratio of each material constituting the paste for negative electrode production, the type of each material constituting the paste for negative electrode production, etc. It can be adjusted by adjusting.
＜負極製造用ペーストの構成材料＞
　次に、本実施形態に係る負極製造用ペーストを構成する各材料について説明する。本実施形態に係る負極製造用ペーストは、負極活物質と、水系バインダーと、増粘剤と、水系媒体と、を含み、さらに必要に応じて導電助剤を含む。 <Material of paste for negative electrode production>
Next, each material which comprises the paste for negative electrode manufacture concerning this embodiment is demonstrated. The paste for manufacturing a negative electrode according to the present embodiment includes a negative electrode active material, an aqueous binder, a thickener, and an aqueous medium, and further contains a conductive auxiliary as required.
（負極活物質）
　本実施形態において、電極活物質としては負極活物質を使用し、負極製造用ペーストが電池用の負極を形成するためのペーストであるときに、本実施形態の剥離強度向上効果を特に効果的に得ることができる。 (Anode active material)
In the present embodiment, when the negative electrode active material is used as the electrode active material and the paste for producing a negative electrode is a paste for forming a negative electrode for a battery, the peel strength improvement effect of the present embodiment is particularly effective. You can get it.
　負極活物質としては、電池の負極に使用可能な通常の負極活物質であれば特に限定されない。上記電池がリチウムイオン電池の場合、例えば、天然黒鉛、人造黒鉛、樹脂炭、炭素繊維、活性炭、ハードカーボン、ソフトカーボン等の炭素材料；リチウム金属、リチウム合金等のリチウム系金属；シリコン、スズ等の金属；ポリアセン、ポリアセチレン、ポリピロール等の導電性ポリマー等が挙げられる。これらの中でも炭素材料が好ましく、特に天然黒鉛や人造黒鉛等の黒鉛質材料が好ましい。
　負極活物質は１種単独で使用してもよいし、２種以上を組み合わせて使用してもよい。 The negative electrode active material is not particularly limited as long as it is a common negative electrode active material that can be used for the battery negative electrode. When the battery is a lithium ion battery, for example, carbon materials such as natural graphite, artificial graphite, resin charcoal, carbon fiber, activated carbon, hard carbon, soft carbon; lithium metals such as lithium metal, lithium alloy; silicon, tin, etc. Conductive polymers such as polyacene, polyacetylene, polypyrrole and the like. Among these, carbon materials are preferable, and particularly graphitic materials such as natural graphite and artificial graphite are preferable.
The negative electrode active material may be used singly or in combination of two or more.
　負極活物質の含有量は、負極製造用ペーストの固形分の全量を１００質量部としたとき、７０質量部以上９９．９７質量部以下であることが好ましく、８５質量部以上９９．８５質量部以下であることがより好ましい。 The content of the negative electrode active material is preferably 70 parts by mass or more and 99.97 parts by mass or less, and 85 parts by mass or more and 99.85 parts by mass, based on 100 parts by mass of the total solid content of the paste for negative electrode production It is more preferable that
　黒鉛質材料としては、電池の負極に使用可能な通常の黒鉛質材料であれば特に限定されない。上記電池がリチウムイオン電池の場合、例えば、天然黒鉛、石油系および石炭系コークスを熱処理することで製造される人造黒鉛等が挙げられる。
　ここで、天然黒鉛とは、鉱石として天然に産出する黒鉛のことをいう。本実施形態の核材として用いる天然黒鉛は、産地や性状、種類は特に限定されない。
　また、人造黒鉛とは、人工的な手法で作られた黒鉛および黒鉛の完全結晶に近い黒鉛をいう。このような人造黒鉛は、例えば、石炭の乾留、原油の蒸留による残渣等から得られるタールやコークスを原料にして、焼成工程、黒鉛化工程を経ることにより得られる。 The graphitic material is not particularly limited as long as it is an ordinary graphitic material usable for the negative electrode of the battery. When the said battery is a lithium ion battery, artificial graphite etc. which are manufactured by heat-processing natural graphite and petroleum type and coal type coke etc. are mentioned, for example.
Here, natural graphite refers to graphite naturally produced as ore. The natural graphite used as the core material of the present embodiment is not particularly limited in terms of production area, properties, and type.
In addition, artificial graphite refers to graphite made in an artificial manner and graphite close to a perfect crystal of graphite. Such artificial graphite can be obtained, for example, by using tar and coke obtained from dry distillation of coal, residue of crude oil distillation and the like as a raw material and passing through a firing step and graphitization step.
　また、黒鉛質材料は、黒鉛粉末を核材とし、上記黒鉛粉末の表面の少なくとも一部が上記黒鉛粉末よりも結晶性の低い炭素材料により被覆されているもの（以下、表面被覆黒鉛とも呼ぶ。）が好ましい。特に黒鉛粉末のエッジ部が上記炭素材料により被覆されていることが好ましい。黒鉛粉末のエッジ部が被覆されることにより、エッジ部と電解液との不可逆的な反応を抑制することができ、その結果、不可逆容量の増大による初期の充放電効率の低下を抑制することができる。
　また、表面被覆黒鉛を用いると、黒鉛単独のときよりもバインダーとの結着性を向上させることができるため、バインダーの量を減らすことができる。その結果、得られる電池の電池特性を向上させることができる。
　ここで、上記黒鉛粉末よりも結晶性の低い炭素材料とは、例えば、ソフトカーボン、ハードカーボン等のアモルファスカーボンである。 Further, the graphitic material has a graphite powder as a core material, and at least a part of the surface of the graphite powder is coated with a carbon material having a crystallinity lower than that of the graphite powder (hereinafter also referred to as surface-coated graphite). Is preferred. In particular, the edge portion of the graphite powder is preferably coated with the above-mentioned carbon material. By covering the edge portion of the graphite powder, it is possible to suppress the irreversible reaction between the edge portion and the electrolytic solution, and as a result, to suppress the decrease in the initial charge / discharge efficiency due to the increase of the irreversible capacity. it can.
In addition, when surface-coated graphite is used, the binding property with the binder can be improved as compared to the case of using graphite alone, so that the amount of binder can be reduced. As a result, the battery characteristics of the obtained battery can be improved.
Here, the carbon material having lower crystallinity than the above-mentioned graphite powder is, for example, amorphous carbon such as soft carbon and hard carbon.
　核材として用いる黒鉛粉末としては、例えば、天然黒鉛、石油系および石炭系コークスを熱処理することで製造される人造黒鉛等が挙げられる。本実施形態においては、これらの黒鉛粉末を一種単独で用いてもよく、二種以上を組み合わせて用いてもよい。これらの中でも、コストの点から、天然黒鉛が好ましい。 Examples of graphite powder used as a core material include natural graphite, artificial graphite produced by heat-treating petroleum-based and coal-based coke, and the like. In the present embodiment, these graphite powders may be used singly or in combination of two or more. Among these, natural graphite is preferable in terms of cost.
　本実施形態に係る表面被覆黒鉛は、焼成工程により炭素化されて上記黒鉛粉末よりも結晶性の低い炭素材料となる有機化合物と、上記黒鉛粉末とを混合した後に、上記有機化合物を焼成炭素化することによって作製することができる。 The surface-coated graphite according to the present embodiment is a mixture of an organic compound which is carbonized in a firing step to become a carbon material having a lower crystallinity than the graphite powder, and the graphite powder, and then the carbonization of the organic compound is performed. It can be produced by
　上記黒鉛粉末と混合する有機化合物は、焼成することによって炭素化して、上記黒鉛粉末よりも結晶性の低い炭素材料が得られるものであれば特に限定されないが、例えば、石油系タール、石炭系タール等のタール；石油系ピッチ、石炭系ピッチ等のピッチ；ポリ塩化ビニル、ポリビニルアセテート、ポリビニルブチラール、ポリビニルアルコール、ポリ塩化ビニリデン、ポリアクリロニトリル等の熱可塑性樹脂；フェノール樹脂、フルフリルアルコール樹脂等の熱硬化性樹脂；セルロース等の天然樹脂；ナフタレン、アルキルナフタレン、アントラセン等の芳香族炭化水素等が挙げられる。
　本実施形態においては、これらの有機化合物は一種単独で用いてもよく、二種以上を組み合わせて用いてもよい。また、これらの有機化合物は、必要に応じて、溶媒により溶解または分散させて用いてもよい。
　上記有機化合物の中でも、価格の点からタールおよびピッチが好ましい。 The organic compound to be mixed with the above-mentioned graphite powder is not particularly limited as long as it can be carbonized by firing to obtain a carbon material having a crystallinity lower than that of the above-mentioned graphite powder. Tars such as petroleum pitches, pitches such as coal pitches; thermoplastic resins such as polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, polyvinyl alcohol, polyvinylidene chloride and polyacrylonitrile; heat such as phenol resin and furfuryl alcohol resin Curable resins; natural resins such as cellulose; and aromatic hydrocarbons such as naphthalene, alkyl naphthalene and anthracene.
In the present embodiment, these organic compounds may be used singly or in combination of two or more. In addition, these organic compounds may be used as dissolved or dispersed in a solvent, as necessary.
Among the above organic compounds, tar and pitch are preferable in terms of price.
　本実施形態に係る表面被覆黒鉛における有機化合物由来の炭素材料の割合（以下「被覆量」と呼ぶ。）は、負極活物質を１００質量％としたとき、好ましくは０．７質量％以上８．０質量％以下である。
　炭素材料の被覆量を上記上限値以下とすることにより、リチウムイオンを吸蔵・放出する面積が大きくなり、得られるリチウムイオン電池のレート特性を向上させることができる。
　炭素材料の被覆量を上記下限値以上とすることにより、不可逆容量の増大による初期の充放電効率の低下を抑制することができる。また、炭素材料の被覆量を上記下限値以上とすることにより、得られる負極製造用ペーストの安定性を向上させることができる。
　ここで、上記被覆量は、熱重量分析により算出することができる。より具体的には、熱重量分析計（例えば、パーキンエルマ社製ＴＧＡ７アナライザ）を用いて、酸素雰囲気下、昇温速度５℃／ｍｉｎにて負極活物質を９００℃まで昇温したとき、質量減少が始まった温度から、質量減少割合が緩やかになり、その後質量減少が加速する温度までの減少質量を被覆量とすることができる。 The ratio of the carbon material derived from the organic compound in the surface-coated graphite according to the present embodiment (hereinafter referred to as "coating amount") is preferably 0.7% by mass or more, based on 100% by mass of the negative electrode active material. It is 0 mass% or less.
By setting the coating amount of the carbon material to the upper limit value or less, the area for occluding and releasing lithium ions can be increased, and the rate characteristics of the obtained lithium ion battery can be improved.
By setting the coating amount of the carbon material to the above lower limit value or more, it is possible to suppress the initial decrease in charge / discharge efficiency due to the increase in irreversible capacity. Moreover, the stability of the paste for negative electrode manufacture obtained can be improved by making the coating amount of a carbon material more than the said lower limit.
Here, the coating amount can be calculated by thermogravimetric analysis. More specifically, when the temperature of the negative electrode active material is raised to 900 ° C. at a temperature rising rate of 5 ° C./min in an oxygen atmosphere using a thermogravimetric analyzer (for example, TGA7 analyzer manufactured by Perkin Elma Co., Ltd.) The reduced mass from the temperature at which the reduction started to the temperature at which the mass reduction rate becomes gradual and then the mass reduction accelerates can be used as the coating amount.
　負極活物質の窒素吸着ＢＥＴ法による比表面積は、好ましくは１．０ｍ２／ｇ以上６．０ｍ２／ｇ以下であり、より好ましくは２．０ｍ２／ｇ以上５．０ｍ２／ｇ以下である。
　比表面積を上記上限値以下とすることにより、不可逆容量の増大による初期の充放電効率の低下を抑制することができる。また、比表面積を上記上限値以下とすることにより、得られる負極製造用ペーストの安定性を向上させることができる。
　比表面積を上記下限値以上とすることにより、リチウムイオンを吸蔵・放出する面積が大きくなり、得られるリチウムイオン電池のレート特性を向上させることができる。
　また、比表面積を上記範囲内とすることにより、水系バインダーの結着性を向上させることができる。 The specific surface area of the negative electrode active material according to the nitrogen adsorption BET method is preferably 1.0 m 2 / g or more and 6.0 m 2 / g or less, more preferably 2.0 m 2 / g or more and 5.0 m 2 / g or less is there.
By setting the specific surface area to the upper limit value or less, it is possible to suppress the decrease in the initial charge / discharge efficiency due to the increase in the irreversible capacity. Moreover, the stability of the paste for negative electrode manufacture obtained can be improved by below a specific surface area being below the said upper limit.
By setting the specific surface area to the above lower limit value or more, the area for absorbing and releasing lithium ions can be increased, and the rate characteristics of the obtained lithium ion battery can be improved.
Moreover, the binding property of the water-based binder can be improved by setting the specific surface area within the above range.
　負極活物質の平均粒子径は、充放電時の副反応を抑えて充放電効率の低下を抑える点から、１μｍ以上が好ましく、３μｍ以上がより好ましく、５μｍ以上がさらに好ましく、８μｍ以上が特に好ましく、入出力特性や電極作製上の観点（電極表面の平滑性等)から、５０μｍ以下が好ましく、４０μｍ以下がより好ましく、３０μｍ以下が特に好ましい。ここで、平均粒径は、レーザ回折散乱法による粒度分布（体積基準)における積算値５０％での粒子径（メジアン径：ｄ５０）を意味する。 The average particle diameter of the negative electrode active material is preferably 1 μm or more, more preferably 3 μm or more, still more preferably 5 μm or more, and particularly preferably 8 μm or more, from the viewpoint of suppressing side reactions during charge and discharge and suppressing decrease in charge and discharge efficiency. Or 50 μm or less is preferable, 40 μm or less is more preferable, and 30 μm or less is particularly preferable from the viewpoint of input / output characteristics and electrode production (smoothness of electrode surface etc.). Here, the average particle diameter means a particle diameter (median diameter: d 50 ) at an integrated value of 50% in a particle size distribution (volume basis) by a laser diffraction scattering method.
（水系バインダー）
　水系バインダーは、電極成形が可能であり、十分な電気化学的安定性を有していれば特に限定されないが、例えば、ゴム系バインダー樹脂やアクリル系バインダー樹脂等を用いることができる。なお、本実施形態において、水系バインダー樹脂とは、水に分散してエマルジョン水溶液を形成できるものをいう。
　本実施形態に係る水系バインダーはラテックス粒子により形成され、水に分散させてエマルジョン水溶液として用いることが好ましい。すなわち、本実施形態に係る水系バインダーは、水系バインダーのラテックス粒子により形成されていることが好ましい。これにより、負極活物質間や導電助剤間、負極活物質と導電助剤との間との接触を阻害せず、水系バインダー樹脂を負極活物質層中に含有させることができる。 (Water-based binder)
The aqueous binder is not particularly limited as long as it can be electrode-shaped and has sufficient electrochemical stability. For example, a rubber binder resin or an acrylic binder resin can be used. In the present embodiment, the aqueous binder resin refers to one that can be dispersed in water to form an aqueous emulsion solution.
The aqueous binder according to the present embodiment is formed of latex particles, and is preferably dispersed in water and used as an aqueous emulsion solution. That is, the water-based binder according to the present embodiment is preferably formed of latex particles of the water-based binder. Thus, the aqueous binder resin can be contained in the negative electrode active material layer without inhibiting the contact between the negative electrode active material, between the conductive support agents, and between the negative electrode active material and the conductive support agent.
　ゴム系バインダー樹脂としては、例えば、スチレン・ブタジエン共重合体ゴム等が挙げられる。
　アクリル系バインダー樹脂としては、例えば、アクリル酸、メタクリル酸、アクリル酸エステル、メタクリル酸エステル、アクリル酸塩、またはメタクリル酸塩の単位（以下「アクリル単位」という）を含む重合体（単独重合体又は共重合体）等が挙げられる。この共重合体としては、アクリル単位とスチレン単位を含む共重合体、アクリル単位とシリコン単位を含む共重合体等が挙げられる。
　これらの水系バインダー樹脂は一種単独で用いてもよく、二種以上を組み合わせて用いてもよい。これらの中でも、結着性、電解液との親和性、価格および電気化学安定性等に優れる点から、スチレン・ブタジエン共重合体ゴムが特に好ましい。 Examples of the rubber-based binder resin include styrene-butadiene copolymer rubber and the like.
As the acrylic binder resin, for example, a polymer (homopolymer or homopolymer containing units of acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, acrylic acid salt, or methacrylic acid salt (hereinafter referred to as “acrylic unit”) Copolymers) and the like. As this copolymer, a copolymer containing an acryl unit and a styrene unit, a copolymer containing an acryl unit and a silicon unit, and the like can be mentioned.
These aqueous binder resins may be used singly or in combination of two or more. Among these, styrene-butadiene copolymer rubbers are particularly preferable in terms of excellent binding properties, affinity with an electrolytic solution, cost and electrochemical stability.
　水系バインダーの含有量は、負極製造用ペーストの固形分の全量を１００質量部としたとき、０．０１質量部以上１０．０質量部以下であることが好ましく、０．０５質量部以上５．０質量部以下であることがより好ましい。水系バインダーの含有量が上記範囲内であると、負極製造用ペーストの塗工性、バインダーの結着性および電池特性のバランスがより一層優れる。 The content of the water-based binder is preferably 0.01 parts by mass or more and 10.0 parts by mass or less, and 0.05 parts by mass or more, based on 100 parts by mass of the total solid content of the paste for negative electrode production. More preferably, it is 0 parts by mass or less. The balance of the coating property of the paste for negative electrode manufacture, the binding property of a binder, and battery characteristics as the content of an aqueous binder is in the said range is much more excellent.
　水系バインダーは、例えば、粉末状のものを水系媒体に分散させてエマルジョン水溶液として用いる。これにより、負極活物質間や導電助剤間、負極活物質と導電助剤との間との接触を阻害せず、水系バインダーの分散性を向上させることができる。
　水系バインダーを分散させる水系媒体については、水系バインダーを分散できるものであれば特に限定されないが、蒸留水、イオン交換水、市水、工業用水等を使用できる。これらの中でも、蒸留水やイオン交換水が好ましい。また、水には、アルコール等の水と親水性の高い溶媒を混合させてもよい。 As the aqueous binder, for example, a powdery one is dispersed in an aqueous medium and used as an aqueous emulsion solution. Thus, the dispersibility of the water-based binder can be improved without inhibiting the contact between the negative electrode active material, the conductive auxiliary agent, and the negative electrode active material and the conductive auxiliary agent.
The aqueous medium in which the aqueous binder is dispersed is not particularly limited as long as it can disperse the aqueous binder, but distilled water, ion exchanged water, city water, industrial water, etc. can be used. Among these, distilled water and ion exchange water are preferable. In addition, water may be mixed with water such as alcohol and a highly hydrophilic solvent.
　スチレン・ブタジエン共重合体ゴムは、スチレンと１，３－ブタジエンを主成分とする共重合体である。ここで、主成分とは、スチレン・ブタジエン共重合体ゴム中において、スチレン由来の構成単位および１，３－ブタジエン由来の構成単位の合計含有量が、スチレン・ブタジエン共重合体ゴムの全重合単位中５０質量％以上の場合をいう。
　スチレン由来の構成単位（以下、Ｓｔとも呼ぶ。）と１，３－ブタジエン由来の構成単位（以下、ＢＤとも呼ぶ。）との質量比（Ｓｔ／ＢＤ）は、例えば、１０／９０～９０／１０である。 The styrene-butadiene copolymer rubber is a copolymer containing styrene and 1,3-butadiene as main components. Here, the main component means that the total content of the structural unit derived from styrene and the structural unit derived from 1,3-butadiene in the styrene-butadiene copolymer rubber is the total polymerization unit of the styrene-butadiene copolymer rubber 50% by mass or more.
The mass ratio (St / BD) of the structural unit derived from styrene (hereinafter also referred to as St) and the structural unit derived from 1,3-butadiene (hereinafter also referred to as BD) is, for example, 10/90 to 90 /. 10
　スチレン・ブタジエン共重合体ゴムは、スチレンおよび１，３－ブタジエン以外のモノマー成分を共重合させてもよい。例えば、共役ジエン系モノマー、不飽和カルボン酸モノマー、その他共重合可能である公知のモノマー等が挙げられる。
　共役ジエン系モノマーとしては、例えば、イソプレン、２，３－ジメチル－１，３－ブタジエン、１，３－ペンタジエン、ピペリレン等が挙げられる。
　不飽和カルボン酸モノマーとしては、例えば、アクリル酸、メタクリル酸、マレイン酸、フマル酸、イタコン酸等が挙げられる。 The styrene butadiene copolymer rubber may be copolymerized with monomer components other than styrene and 1,3-butadiene. For example, conjugated diene-based monomers, unsaturated carboxylic acid monomers, other known copolymerizable monomers, and the like can be mentioned.
Examples of the conjugated diene-based monomer include isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, piperylene and the like.
Examples of unsaturated carboxylic acid monomers include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid and the like.
　スチレン・ブタジエン共重合体ゴムの製造方法は特に限定されないが、乳化重合法により製造することが好ましい。乳化重合法を用いると、スチレン・ブタジエン共重合体ゴムを含むラテックス粒子で得ることができる。
　乳化重合としては従来既知の方法を用いることができる。例えば、スチレンと、１，３－ブタジエンと、さらには上記の各種共重合可能なモノマー成分とを、好ましくは乳化剤の存在下、重合開始剤を添加し、水中で乳化重合することにより製造することができる。 Although the manufacturing method of a styrene butadiene copolymer rubber is not specifically limited, It is preferable to manufacture by an emulsion polymerization method. When emulsion polymerization is used, it can be obtained as latex particles containing a styrene-butadiene copolymer rubber.
Conventionally known methods can be used as the emulsion polymerization. For example, it is produced by emulsion polymerization in water by adding a polymerization initiator, preferably in the presence of an emulsifying agent, of styrene, 1,3-butadiene, and various copolymerizable monomer components described above. Can.
（増粘剤）
　増粘剤は、負極製造用ペーストの塗工性を向上させるものであれば特に限定されない。増粘剤としては、例えば、セルロース系水溶性高分子；ポリカルボン酸；ポリエチレンオキシド；ポリビニルピロリドン；ポリアクリル酸ナトリウム等のポリアクリル酸塩；ポリビニルアルコール；等の水溶性ポリマーが挙げられる。これらの増粘剤は１種単独で使用してもよいし、２種以上を組み合わせて使用してもよい。
　これらの中でもセルロース系水溶性高分子が好ましい。 (Thickener)
The thickener is not particularly limited as long as it improves the coatability of the paste for negative electrode production. Examples of the thickener include water-soluble polymers such as cellulose-based water-soluble polymers; polycarboxylic acids; polyethylene oxide; polyvinyl pyrrolidone; polyacrylates such as sodium polyacrylate; These thickeners may be used alone or in combination of two or more.
Among these, cellulose-based water-soluble polymers are preferable.
　セルロース系水溶性高分子としては負極製造用ペーストの塗工性を向上させるものであれば特に限定されない。セルロース系水溶性高分子としては、例えば、カルボキシメチルセルロース、ヒドロキシメチルセルロース、ヒドロキシエチルセルロース、メチルエチルヒドロキシセルロース、メチルセルロース、ヒドロキシプロピルセルロース等のセルロース系ポリマー、およびこれらのセルロース系ポリマーのアンモニウム塩並びにアルカリ金属塩等のセルロース系ポリマー塩等から選択される一種または二種以上を用いることができる。
　これらの中でもカルボキシメチルセルロースおよびカルボキシメチルセルロース塩から選択される少なくとも一種を含むことが好ましく、カルボキシメチルセルロース、カルボキシメチルセルロースのアンモニウム塩、カルボキシメチルセルロースのナトリウム塩およびカルボキシメチルセルロースのカリウム塩から選択される一種または二種以上を含むことがより好ましい。 The cellulose-based water-soluble polymer is not particularly limited as long as it improves the coatability of the paste for negative electrode production. Examples of cellulose-based water-soluble polymers include cellulose-based polymers such as carboxymethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, methylethylhydroxycellulose, methylcellulose and hydroxypropylcellulose, and ammonium salts and alkali metal salts of these cellulose-based polymers It is possible to use one or two or more selected from cellulose-based polymer salts and the like.
Among these, it is preferable to include at least one selected from carboxymethylcellulose and carboxymethylcellulose salt, and one or more selected from carboxymethylcellulose, ammonium salt of carboxymethylcellulose, sodium salt of carboxymethylcellulose and potassium salt of carboxymethylcellulose. More preferably,
　セルロース系水溶性高分子の水系媒体への溶解性を向上させ、負極製造用ペーストの固形分濃度を高めることができる点や、得られる負極製造用ペーストの弾性率を向上させることができる点等から、セルロース系水溶性高分子のエーテル化度は０．５０以上１．０以下であることが好ましく、０．７０以上０．９０以下であることがより好ましい。
　ここで、エーテル化度とは、セルロース系水溶性高分子中の無水グルコース単位１個当たりの水酸基のカルボキシメチル基等への置換体への置換度のことをいう。 It is possible to improve the solubility of the cellulose-based water-soluble polymer in the aqueous medium and to increase the solid content concentration of the paste for producing a negative electrode, and to improve the elastic modulus of the obtained paste for producing a negative electrode, etc. Therefore, the degree of etherification of the cellulose-based water-soluble polymer is preferably 0.50 or more and 1.0 or less, and more preferably 0.70 or more and 0.90 or less.
Here, the degree of etherification refers to the degree of substitution of a hydroxyl group per anhydroglucose unit in a cellulose-based water-soluble polymer with a substituent to a carboxymethyl group or the like.
　ゲルパーミエーションクロマトグラフィー（ＧＰＣ）により測定される、セルロース系水溶性高分子の重量平均分子量Ｍｗ（ポリエチレングリコール換算値）は、１０００００以上であることが好ましく、２０００００以上であることがより好ましい。セルロース系水溶性高分子の重量平均分子量Ｍｗが上記下限値以上であると、本実施形態に係る負極製造用ペーストの貯蔵弾性率を効果的に高めることができる。
　また、ＧＰＣにより測定される、セルロース系水溶性高分子の重量平均分子量Ｍｗ（ポリエチレングリコール換算値）は、９０００００以下であることが好ましく、８０００００以下であることがより好ましい。セルロース系水溶性高分子の重量平均分子量Ｍｗが上記上限値以下であると、セルロース系水溶性高分子の水系媒体への溶解性が向上し、負極製造用ペーストの固形分濃度を高めることができ、その結果、本実施形態に係る負極製造用ペーストの貯蔵弾性率を効果的に高めることができる。 The weight average molecular weight Mw (in terms of polyethylene glycol) of the cellulose-based water-soluble polymer, which is measured by gel permeation chromatography (GPC), is preferably 100,000 or more, and more preferably 200,000 or more. The storage elastic modulus of the paste for manufacturing a negative electrode according to the present embodiment can be effectively increased when the weight average molecular weight Mw of the cellulose-based water-soluble polymer is not less than the above lower limit value.
Moreover, it is preferable that it is 900000 or less, and, as for the weight average molecular weight Mw (polyethylene glycol conversion value) of a cellulose type water-soluble polymer measured by GPC, it is more preferable that it is 800000 or less. When the weight average molecular weight Mw of the cellulose-based water-soluble polymer is less than or equal to the above upper limit, the solubility of the cellulose-based water-soluble polymer in the aqueous medium is improved, and the solid content concentration of the paste for negative electrode production can be increased. As a result, the storage elastic modulus of the paste for manufacturing a negative electrode according to this embodiment can be effectively increased.
　増粘剤の含有量は、負極製造用ペーストの固形分の全量を１００質量部としたとき、０．０１質量部以上１０．０質量部以下であることが好ましく、０．０５質量部以上５．０質量部以下であることがより好ましい。増粘剤の含有量が上記範囲内であると、負極製造用ペーストの塗工性、バインダーの結着性および電池特性のバランスがより一層優れる。 The content of the thickener is preferably 0.01 parts by mass or more and 10.0 parts by mass or less, and preferably 0.05 parts by mass or more, based on 100 parts by mass of the total solid content of the paste for negative electrode production. It is more preferable that it is not more than 0 parts by mass. The balance of the coating property of the paste for negative electrode manufacture, the binding property of a binder, and battery characteristics as the content of a thickener is in the said range is much more excellent.
（導電助剤）
　本実施形態に係る負極製造用ペーストは、得られる電極の電子伝導性を向上させる観点から、導電助剤をさらに含むことが好ましい。
　導電助剤は、電子伝導性を有しており、電極の導電性を向上させるものであれば特に限定されない。本実施形態に係る導電助剤としては、例えば、アセチレンブラック、ケッチェンブラック、カーボンブラック、カーボンナノファイバー、活物質として使用される黒鉛よりも粒子径の小さい黒鉛等の炭素材料が挙げられる。これらの導電助剤は１種単独で使用してもよいし、２種以上を組み合わせて使用してもよい。 (Conduction agent)
From the viewpoint of improving the electron conductivity of the obtained electrode, the paste for producing a negative electrode according to this embodiment preferably further includes a conductive aid.
The conductive aid is not particularly limited as long as it has electron conductivity and improves the conductivity of the electrode. Examples of the conductive additive according to this embodiment include carbon materials such as acetylene black, ketjen black, carbon black, carbon nanofibers, and graphite having a particle diameter smaller than that of graphite used as an active material. These conductive aids may be used alone or in combination of two or more.
　導電助剤の含有量は、負極製造用ペーストの固形分の全量を１００質量部としたとき、０．０１質量部以上１０．０質量部以下であることが好ましく、０．０５質量部以上５．０質量部以下であることがより好ましい。
　導電助剤の含有量が上記範囲内であると、負極製造用ペーストの塗工性およびバインダーの結着性のバランスがより一層優れる。 The content of the conductive additive is preferably 0.01 parts by mass or more and 10.0 parts by mass or less, and 0.05 parts by mass or more, based on 100 parts by mass of the total solid content of the paste for negative electrode production. It is more preferable that it is not more than 0 parts by mass.
The balance of the coating property of the paste for negative electrode manufacture and the binding property of a binder as the content of a conductive support agent is in the said range is much more excellent.
　導電助剤の窒素吸着ＢＥＴ法による比表面積は、負極製造用ペーストの塗工性および電極の伝導性のバランスの点から、好ましくは５０ｍ２／ｇ以上１０００ｍ２／ｇ以下である。 The specific surface area by the nitrogen adsorption BET method of the conductive additive is preferably 50 m 2 / g or more and 1000 m 2 / g or less from the viewpoint of the balance between the coatability of the paste for producing a negative electrode and the conductivity of the electrode.
（水系媒体）
　本実施形態に係る水系媒体については特に限定されず、例えば、蒸留水、イオン交換水、市水、工業用水等を使用できる。これらの中でも、蒸留水やイオン交換水が好ましい。また、水には、アルコール等の水と親水性の高い溶媒を混合させてもよい。 (Water based medium)
It does not specifically limit about the aqueous medium which concerns on this embodiment, For example, distilled water, ion-exchange water, city water, industrial water etc. can be used. Among these, distilled water and ion exchange water are preferable. In addition, water may be mixed with water such as alcohol and a highly hydrophilic solvent.
　本実施形態に係る負極製造用ペーストは、負極製造用ペーストの固形分の全量を１００質量部としたとき、負極活物質の含有量は好ましくは７０質量部以上９９．９７質量部以下であり、より好ましくは８５質量部以上９９．８５質量部以下である。また、水系バインダーの含有量は好ましくは０．０１質量部以上１０．０質量部以下であり、より好ましくは０．０５質量部以上５．０質量部以下である。また、増粘剤の含有量は好ましくは０．０１質量部以上１０．０質量部以下であり、より好ましくは０．０５質量部以上５．０質量部以下である。また、導電助剤の含有量は好ましくは０．０１質量部以上１０．０質量部以下であり、より好ましくは０．０５質量部以上５．０質量部以下である。
　負極製造用ペーストを構成する各成分の含有量が上記範囲内であると、負極製造用ペーストの品質安定性と、得られる電池の電池特性のバランスが特に優れる。 The content of the negative electrode active material is preferably 70 parts by mass or more and 99.97 parts by mass or less, when the total content of the solid content of the paste for negative electrode manufacture is 100 parts by mass, in the paste for negative electrode manufacture according to the present embodiment. More preferably, it is 85 parts by mass or more and 99.85 parts by mass or less. The content of the aqueous binder is preferably 0.01 parts by mass or more and 10.0 parts by mass or less, and more preferably 0.05 parts by mass or more and 5.0 parts by mass or less. Further, the content of the thickener is preferably 0.01 parts by mass or more and 10.0 parts by mass or less, and more preferably 0.05 parts by mass or more and 5.0 parts by mass or less. Moreover, content of a conductive support agent becomes like this. Preferably it is 0.01 to 10.0 mass parts, More preferably, it is 0.05 to 5.0 mass parts.
The balance of the quality stability of the paste for negative electrode manufacture and the battery characteristic of the battery obtained as the content of each component which comprises the paste for negative electrode manufacture is in the said range is especially excellent.
＜負極製造用ペーストの製造方法＞
　次に、本実施形態に係る水極製造用ペーストの製造方法について説明する。
　本実施形態に係る負極製造用ペーストの製造方法は、負極活物質と、水系バインダーと、増粘剤と、水系媒体と、を含み、さらに必要に応じて導電助剤を含む電池用負極製造用ペーストの製造方法であって、以下の工程（Ａ）～（Ｃ）を少なくとも含む。 <Method of producing paste for producing negative electrode>
Next, a method of producing the paste for producing a water electrode according to the present embodiment will be described.
The method for producing a paste for producing a negative electrode according to the present embodiment includes a negative electrode active material, an aqueous binder, a thickener, and an aqueous medium, and further includes, if necessary, a negative electrode for a battery. A method of producing a paste, comprising at least the following steps (A) to (C):
　乾式混合工程（Ａ）：負極活物質および増粘剤粉末を紛体状態で乾式混合することにより、負極活物質および増粘剤粉末を含む混合物を調製する工程
　ペースト前駆体調製工程（Ｂ）：上記混合物中に、水系媒体および水系バインダーを含むエマルジョン水溶液から選択される一種または二種以上の液体成分を添加して湿式混合することにより、ペースト前駆体を調製する工程
　負極製造用ペースト調製工程（Ｃ）：上記ペースト前駆体中に、水系媒体および水系バインダーを含むエマルジョン水溶液から選択される一種または二種以上の液体成分をさらに添加して湿式混合することにより上記負極製造用ペーストを調製する工程 Dry mixing step (A): a step of preparing a mixture containing the negative electrode active material and the thickener powder by dry mixing the negative electrode active material and the thickener powder in a powder state Paste precursor preparation step (B): A step of preparing a paste precursor by adding one or two or more types of liquid components selected from an aqueous solution and an aqueous emulsion containing an aqueous binder to the mixture and wet mixing to prepare a paste preparation step for negative electrode production (C ): A step of preparing the paste for producing the negative electrode by further adding one or two or more kinds of liquid components selected from an aqueous solution and an aqueous emulsion containing an aqueous binder to the above paste precursor and wet mixing
　乾式混合工程（Ａ）では、負極活物質および増粘剤粉末を紛体状態で乾式混合することにより、負極活物質および増粘剤粉末を含む粉体の混合物を調製する。このとき、導電助剤を合わせて紛体混合してもよい。
　本実施形態において、乾式混合工程（Ａ）をおこなうことにより、負極活物質および増粘剤の分散性を高めることができ、その後の工程において、増粘剤由来のゲル成分の生成をより一層抑制できる。これにより、得られる負極製造用ペースト中の増粘剤由来のゲル成分の発生を抑制できたり、負極製造用ペーストの貯蔵弾性率を向上できたりする。 In the dry mixing step (A), a powder mixture containing the negative electrode active material and the thickener powder is prepared by dry-mixing the negative electrode active material and the thickener powder in a powder state. At this time, the conductive aid may be combined and powder mixed.
In the present embodiment, by performing the dry mixing step (A), the dispersibility of the negative electrode active material and the thickener can be enhanced, and in the subsequent steps, the formation of the gel component derived from the thickener can be further suppressed. it can. Thereby, generation | occurrence | production of the gel component derived from the thickener in the paste for negative electrode manufacture obtained can be suppressed, or the storage elastic modulus of the paste for negative electrode manufacture can be improved.
　乾式混合をおこなう混合機としては、遊星運動型ミキサーを用いるのが好ましく、遊星運動型プラネタリーミキサーを用いることがより好ましい。このような混合機を用いることにより、負極活物質および増粘剤粉末の飛散を抑制しながら、負極活物質および増粘剤粉末を十分に混合することができる。なお、遊星運動型ミキサーは、攪拌機構として自転と公転機能を有しているミキサーのことをいう。遊星運動型プラネタリーミキサーとは、攪拌機構として自転と公転機能を有するブレードをもつミキサーをいう。 As a mixer which performs dry mixing, it is preferable to use a planetary motion type mixer, and it is more preferable to use a planetary motion type planetary mixer. By using such a mixer, the negative electrode active material and the thickener powder can be sufficiently mixed while suppressing scattering of the negative electrode active material and the thickener powder. In addition, a planetary motion type mixer means the mixer which has rotation and revolution function as a stirring mechanism. The planetary motion type planetary mixer refers to a mixer having a blade having rotation and revolution functions as a stirring mechanism.
　乾式混合工程（Ａ）における上記乾式混合の自転速度は、０．０５ｍ／ｓｅｃ以上０．５５ｍ／ｓｅｃ以下の範囲内であることが好ましく、０．０７ｍ／ｓｅｃ以上０．５２ｍ／ｓｅｃ以下の範囲内であることがより好ましい。
　乾式混合工程（Ａ）における上記乾式混合の自転速度が、上記範囲内であると、負極活物質および増粘剤粉末の飛散を抑制しながら、負極活物質および増粘剤粉末を十分に混合することができる。 The rotation speed of the dry mixing in the dry mixing step (A) is preferably in the range of 0.05 m / sec to 0.55 m / sec, and is in the range of 0.07 m / sec to 0.52 m / sec. It is more preferable that it is inside.
The negative electrode active material and the thickener powder are sufficiently mixed while suppressing the scattering of the negative electrode active material and the thickener powder as the rotation speed of the dry mixing in the dry mixing step (A) falls within the above range be able to.
　また、乾式混合工程（Ａ）における上記乾式混合の公転速度は、０．０１ｍ／ｓｅｃ以上０．２０ｍ／ｓｅｃ以下の範囲内であることが好ましく、０．０２ｍ／ｓｅｃ以上０．１５ｍ／ｓｅｃ以下の範囲内であることがより好ましい。
　乾式混合工程（Ａ）における上記乾式混合の公転速度が、上記範囲内であると、負極活物質および増粘剤粉末の飛散を抑制しながら、負極活物質および増粘剤粉末を十分に混合することができる。 Moreover, it is preferable that the revolving speed of the said dry mixing in dry mixing process (A) exists in the range of 0.01 m / sec or more and 0.20 m / sec or less, and 0.02 m / sec or more and 0.15 m / sec or less It is more preferable to be in the range of
The negative electrode active material and the thickener powder are sufficiently mixed while suppressing the scattering of the negative electrode active material and the thickener powder as the revolution speed of the dry mixing in the dry mixing step (A) falls within the above range be able to.
　乾式混合工程（Ａ）における上記乾式混合の混合時間は、特に限定されないが、例えば、５分以上１２０分以下、好ましくは１０分以上６０分以下である。 The mixing time of the dry mixing in the dry mixing step (A) is not particularly limited, and is, for example, 5 minutes or more and 120 minutes or less, preferably 10 minutes or more and 60 minutes or less.
　ペースト前駆体調製工程（Ｂ）では、工程（Ａ）により得られた上記混合物中に、水系媒体および水系バインダーを含むエマルジョン水溶液から選択される一種または二種以上の液体成分を添加して湿式混合することにより、ペースト前駆体を調製する。 In the paste precursor preparation step (B), one or two or more kinds of liquid components selected from an aqueous medium and an aqueous emulsion solution containing an aqueous binder are added to the above mixture obtained in the step (A) for wet mixing The paste precursor is prepared by
　ペースト前駆体調製工程（Ｂ）における湿式混合をおこなう混合機としては、遊星運動型ミキサーを用いるのが好ましく、遊星運動型プラネタリーミキサーを用いることがより好ましい。このような混合機を用いることにより、負極製造用ペーストを構成する各材料の飛散を抑制しながら、各材料の分散性を高めることができる。 As a mixer which performs wet mixing in the paste precursor preparation process (B), it is preferable to use a planetary motion type mixer, and it is more preferable to use a planetary motion type planetary mixer. By using such a mixer, the dispersibility of each material can be enhanced while suppressing scattering of each material constituting the paste for negative electrode production.
　ここで、ペースト前駆体調製工程（Ｂ）は、第１の固練り工程（Ｂ２）と、第２の固練り工程（Ｂ３）とを少なくとも含む、二段階以上の工程とする。さらに必要に応じて、第１の固練り工程（Ｂ２）の前に行う、なじませ工程（Ｂ１）を行ってもよい。 Here, the paste precursor preparation step (B) is a two or more step including at least a first solidifying step (B2) and a second solidifying step (B3). Furthermore, if necessary, a blending step (B1) may be performed prior to the first solidifying step (B2).
　なじませ工程（Ｂ１）は、紛体混合物に水系媒体および水系バインダーを含むエマルジョン水溶液から選択される一種または二種以上の液体成分をなじませる工程である。このなじませ工程（Ｂ１）を含むことにより、紛体混合物が湿式混合時に混合機のふちにせり上がってくることや、紛体混合物の濡れが偏ってしまうこと、紛体混合物が混練時に飛び散ること等を一定の範囲で抑制できる。 The blending step (B1) is a step of blending the powder mixture with one or more liquid components selected from an aqueous medium and an aqueous emulsion containing a water-based binder. By including the blending step (B1), the powder mixture may rise to the edge of the mixer during wet mixing, the wetting of the powder mixture may be uneven, the powder mixture may be scattered during kneading, etc. In the range of
　なじませ工程（Ｂ１）における上記湿式混合の自転速度は、０．１０ｍ／ｓｅｃ以上０．５０ｍ／ｓｅｃ以下の範囲内であることが好ましく、０．１５ｍ／ｓｅｃ以上０．２０ｍ／ｓｅｃ以下の範囲内であることがより好ましい。
　なじませ工程（Ｂ１）における上記湿式混合の自転速度が上記範囲内であると、紛体混合物が湿式混合時に混合機のふちにせり上がってくることや、紛体混合物の濡れが偏ってしまうこと、紛体混合物が混練時に飛び散ること等をより効果的に抑制しながら、紛体混合物に液体成分を十分になじませることができる。 The rotation speed of the wet mixing in the blending step (B1) is preferably in the range of 0.10 m / sec to 0.50 m / sec, and in the range of 0.15 m / sec to 0.20 m / sec. It is more preferable that it is inside.
If the rotation speed of the wet mixing in the blending step (B1) is within the above range, the powder mixture may rise up to the edge of the mixer during wet mixing, the wetting of the powder mixture may be biased, and the powder The liquid component can be sufficiently mixed with the powder mixture while suppressing the mixture from scattering and the like more effectively at the time of kneading.
　また、なじませ工程（Ｂ１）における上記湿式混合の公転速度は、０．０３ｍ／ｓｅｃ以上０．０６ｍ／ｓｅｃ以下の範囲内であることが好ましく、０．０４ｍ／ｓｅｃ以上０．０６ｍ／ｓｅｃ以下の範囲内であることがより好ましい。
　なじませ工程（Ｂ１）における上記湿式混合の公転速度が上記範囲内であると、紛体混合物が湿式混合時に混合機のふちにせり上がってくることや、紛体混合物の濡れが偏ってしまうこと、紛体混合物が混練時に飛び散ること等をより効果的に抑制しながら、紛体混合物に液体成分を十分になじませることができる。 Moreover, it is preferable that the revolving speed of the said wet mixing in an adaptation process (B1) exists in the range of 0.03 m / sec or more and 0.06 m / sec or less, and 0.04 m / sec or more and 0.06 m / sec or less It is more preferable to be in the range of
If the revolution speed of the wet mixing in the blending step (B1) is within the above range, the powder mixture may rise up to the edge of the mixer during wet mixing, the wetting of the powder mixture may be biased, and the powder The liquid component can be sufficiently mixed with the powder mixture while suppressing the mixture from scattering and the like more effectively at the time of kneading.
　なじませ工程（Ｂ１）における上記湿式混合の混合時間は、特に限定されないが、例えば、０．５分以上１０分以下であることが好ましく、２分以上５分以下であることがより好ましい。 Although the mixing time of the said wet mixing in an adaptation process (B1) is not specifically limited, For example, it is preferable that it is 0.5 to 10 minutes, and it is more preferable that it is 2 to 5 minutes.
　また、第１の固練り工程（Ｂ２）および第２の固練り工程（Ｂ３）は、なじませ工程（Ｂ１）よりも湿式混合の自転速度を高く設定し、上記紛体混合物と上記液体成分とを混練し、ペースト前駆体を得る工程である。 Further, in the first solidifying step (B2) and the second solidifying step (B3), the rotation speed of wet mixing is set higher than in the soaking step (B1), and the powder mixture and the liquid component are It is a process of kneading and obtaining a paste precursor.
　第１の固練り工程（Ｂ２）において、ペースト前駆体の固形分濃度を６８質量％以上７７質量％以下に調整することが好ましく、７０質量％以上７４質量％以下に調整することがより好ましく、７１質量％以上７２質量％以下に調整することがさらに好ましい。
　固形分濃度を上記下限値以上とすることにより、活物質や導電助剤に一定量の増粘剤が吸着することができるため、水系媒体中への増粘剤の過剰な分散が抑制される。以降の負極製造用ペースト調製工程（Ｃ）で添加される水系バインダーが、上記の増粘剤が吸着した活物質や導電助剤に効率よく吸着され、各材料間の相互作用による３次元的なネットワークが発達する。その結果、引き続き上記負極製造用ペーストを集電体に塗布・乾燥して得られる負極電極において、集電体層と負極活物質層との接着性、すなわち剥離強度を、より一層向上させることができる。
　また、固形分濃度を上記上限値以下とすることにより、活物質や導電助剤を含む紛体混合物が湿式混合時に混合機のふちにせり上がってくることを効果的に抑制できるため、安定した粘度・混合比の負極製造用ペーストを得ることができる。 In the first solidifying step (B2), the solid content concentration of the paste precursor is preferably adjusted to 68% by mass to 77% by mass, and more preferably adjusted to 70% by mass to 74% by mass, It is more preferable to adjust to 71% by mass or more and 72% by mass or less.
By setting the solid content concentration to the above lower limit value or more, a certain amount of thickener can be adsorbed to the active material and the conductive auxiliary agent, so excessive dispersion of the thickener in the aqueous medium is suppressed . The aqueous binder to be added in the subsequent paste preparation step (C) for negative electrode production is efficiently adsorbed by the active material and the conductive support agent to which the above-mentioned thickener is adsorbed, and three-dimensional by the interaction between each material Network develops. As a result, in the negative electrode obtained by subsequently applying and drying the above paste for negative electrode production on a current collector, the adhesion between the current collector layer and the negative electrode active material layer, that is, the peel strength is further improved. it can.
Further, by setting the solid content concentration to the upper limit value or less, the powder mixture containing the active material and the conductive additive can be effectively suppressed from rising up to the edge of the mixer at the time of wet mixing, so that the stable viscosity -The paste for negative electrode manufacture of a mixing ratio can be obtained.
　第１の固練り工程（Ｂ２）における上記湿式混合の混合時間は、特に限定されないが、例えば、５分以上６０分以下である。 The mixing time of the wet mixing in the first solidifying step (B2) is not particularly limited, and is, for example, 5 minutes or more and 60 minutes or less.
　第２の固練り工程（Ｂ３）において、ペースト前駆体の固形分濃度を５９質量％以上６６質量％以下に調整することが好ましく、６１質量％以上６４質量％以下に調整することがより好ましく、６２質量％以上６３質量％以下に調整することがさらに好ましい。
　固形分濃度を上記下限値以上とすることにより、固形混合物が所謂ダマの状態になるのを抑制し、均一なペーストを作製することができる。
　また、固形分濃度を上記上限値以下とすることにより、ペースト中に適度に分散した増粘剤が、次の塗布・乾燥工程において、水系バインダーの負極活物質層表面への移動を抑え、その結果、水系バインダーが負極活物質層の表面に偏在してしまうことを抑制できると考えられる。 In the second solidifying step (B3), the solid content concentration of the paste precursor is preferably adjusted to 59% by mass to 66% by mass, and more preferably adjusted to 61% by mass to 64% by mass, It is more preferable to adjust to 62 mass% or more and 63 mass% or less.
By making solid content concentration more than the said lower limit, it can suppress that a solid mixture will be in the state of what is called a lump, and can prepare a uniform paste.
In addition, by setting the solid content concentration to the upper limit value or less, the thickener appropriately dispersed in the paste suppresses the movement of the water-based binder to the surface of the negative electrode active material layer in the next coating and drying step. As a result, it is considered that uneven distribution of the aqueous binder on the surface of the negative electrode active material layer can be suppressed.
　第２の固練り工程（Ｂ３）における上記湿式混合の混合時間は、特に限定されないが、例えば、５分以上６０分以下である。 The mixing time of the wet mixing in the second solidifying step (B3) is not particularly limited, and is, for example, 5 minutes or more and 60 minutes or less.
　第１の固練り工程（Ｂ２）および第２の固練り工程（Ｂ３）における上記湿式混合の自転速度（遊星運動型ミキサーのブレードの線速度）は、０．１０ｍ／ｓｅｃ以上２．０ｍ／ｓｅｃ以下の範囲内であることが好ましく、０．２０ｍ／ｓｅｃ以上１．２ｍ／ｓｅｃ以下の範囲内であることがより好ましい。 The rotation speed (the linear velocity of the blade of the planetary motion mixer) of the wet mixing in the first solidifying step (B2) and the second solidifying step (B3) is 0.10 m / sec or more and 2.0 m / sec or more It is preferable to be in the following range, and it is more preferable to be in the range of 0.20 m / sec or more and 1.2 m / sec or less.
　また、第１の固練り工程（Ｂ２）および第２の固練り工程（Ｂ３）における上記湿式混合の公転速度（遊星運動型ミキサーのブレードの線速度）は、０．０１ｍ／ｓｅｃ以上１．０ｍ／ｓｅｃ以下の範囲内であることが好ましく、０．０５ｍ／ｓｅｃ以上０．３５ｍ／ｓｅｃ以下の範囲内であることがより好ましい。 In addition, the revolution speed (the linear velocity of the blade of the planetary motion mixer) of the above-mentioned wet mixing in the first solidifying step (B2) and the second solidifying step (B3) is 0.01 m / sec or more and 1.0 m or more It is preferable to be in the range of 2 sec or less, and more preferable to be in the range of 0.05 m / sec or more and 0.35 m / sec or less.
　負極製造用ペースト調製工程（Ｃ）では、ペースト前駆体調製工程（Ｂ）により得られた上記ペースト前駆体中に、水系媒体および水系バインダーを含むエマルジョン水溶液から選択される一種または二種以上の液体成分をさらに添加して湿式混合することにより、上記負極製造用ペーストを調製する。 In the paste preparation step (C) for negative electrode production, at least one liquid selected from an aqueous solution containing an aqueous medium and an aqueous binder in the paste precursor obtained in the paste precursor preparation step (B) The above-mentioned paste for producing a negative electrode is prepared by further adding components and wet mixing.
　負極製造用ペースト調製工程（Ｃ）における湿式混合をおこなう混合機としては、遊星運動型ミキサーを用いるのが好ましく、遊星運動型プラネタリーミキサーを用いることがより好ましい。このような混合機を用いることにより、低速で攪拌しながら、十分に混合することができる。そのため、攪拌混合による増粘剤の分子鎖の切断を抑制し、かつ、水系バインダー同士の凝集を抑制しながら、負極製造用ペーストを構成する各材料の分散性を高めることができる。そして、その結果として、品質安定性により一層優れた負極製造用ペーストを得ることができる。
　また、得られる負極製造用ペーストは分散性がより一層優れるため、このような負極製造用ペーストを用いると、より一層均一な負極活物質層を得ることができる。その結果、より一層電池特性に優れた電池を得ることができる。 As a mixer which performs wet mixing in the paste preparation process (C) for negative electrode manufacture, it is preferable to use a planetary motion type mixer, and it is more preferable to use a planetary motion type planetary mixer. By using such a mixer, sufficient mixing can be performed while stirring at low speed. Therefore, the dispersibility of each material which comprises the paste for negative electrode manufacture can be improved, suppressing the cutting | disconnection of the molecular chain of the thickener by stirring and mixing, and suppressing aggregation of water-based binders. And as a result, the paste for negative electrode manufacture more excellent by quality stability can be obtained.
Further, since the obtained paste for producing a negative electrode is further excellent in dispersibility, when such a paste for producing a negative electrode is used, it is possible to obtain a much more uniform negative electrode active material layer. As a result, a battery having even more excellent battery characteristics can be obtained.
　本実施形態において、負極製造用ペースト調製工程（Ｃ）における湿式混合の自転速度（遊星運動型ミキサーのブレードの線速度）は特に限定されないが、例えば、０．１０ｍ／ｓｅｃ以上１０．０ｍ／ｓｅｃ以下の範囲内である。
　また、本実施形態において、負極製造用ペースト調製工程（Ｃ）における湿式混合の公転速度（遊星運動型ミキサーのブレードの線速度）は特に限定されないが、例えば、０．０２ｍ／ｓｅｃ以上３．０ｍ／ｓｅｃ以下の範囲内である。 In the present embodiment, the rotation speed of the wet mixing (linear velocity of the blade of the planetary motion mixer) in the paste preparation step (C) for producing a negative electrode is not particularly limited, but is, for example, 0.10 m / sec or more and 10.0 m / sec. It is in the following range.
Further, in the present embodiment, the revolution speed of the wet mixing (linear velocity of the blade of the planetary motion mixer) in the paste preparation step (C) for negative electrode production is not particularly limited, but is, for example, 0.02 m / sec or more and 3.0 m or more It is in the range below / sec.
　負極製造用ペースト調製工程（Ｃ）における上記湿式混合の混合時間は、特に限定されないが、例えば、５分以上６０分以下である。 Although the mixing time of the said wet mixing in the paste preparation process (C) for negative electrode manufacture is not specifically limited, For example, they are 5 minutes or more and 60 minutes or less.
　なお、負極製造用ペースト調製工程（Ｃ）における負極製造用ペーストの固形分濃度は、上記液体成分の濃度や添加量を調整することにより調整することができる。 In addition, solid content concentration of the paste for negative electrode manufacture in the paste preparation process (C) for negative electrode manufacture can be adjusted by adjusting the density | concentration and addition amount of the said liquid component.
　本実施形態に係る負極製造用ペーストの製造方法は、脱泡工程（Ｄ）：真空脱泡する工程をさらにおこなってもよい。これにより、ペースト中に巻き込んだ気泡を取り除くことができ、ペーストの塗工性を向上させることができる。
　真空脱泡は混合機の容器や軸部にシール処理を施して気泡を除去してもよいし、別の容器に移してから行ってもよい。 The method for producing a paste for producing a negative electrode according to the present embodiment may further include the step of degassing step (D): vacuum degassing. Thereby, air bubbles caught in the paste can be removed, and the coatability of the paste can be improved.
The vacuum degassing may be performed by sealing the container or shaft of the mixer to remove air bubbles, or by transferring it to another container.
＜電池用負極電極＞
　図１は、本発明に係る実施形態の電池用負極電極１００の構造の一例を示す断面図である。本実施形態に係る電池用負極電極１００は、集電体層１０１と、集電体層１０１の少なくとも一方の面に設けられ、かつ、本実施形態に係る負極製造用ペーストの固形分により形成された負極活物質層１０３と、を含む。 <Anode for battery>
FIG. 1 is a cross-sectional view showing an example of the structure of a battery negative electrode 100 according to an embodiment of the present invention. The battery negative electrode 100 according to the present embodiment is provided on at least one of the current collector layer 101 and the current collector layer 101, and is formed of the solid content of the negative electrode production paste according to the present embodiment. And the negative electrode active material layer 103.
　本実施形態に係る電池用負極電極１００の製造に用いられる集電体層１０１としては、例えば、電池に使用可能な通常の集電体を用いることができる。
　上記電池がリチウムイオン電池の場合、負極集電体としては、例えば、銅、ステンレス鋼、ニッケル、チタンまたはこれらの合金を用いることができ、これらの中でも銅が特に好ましい。
　集電体の形状については特に限定されないが、例えば、厚さが０．００１～０．５ｍｍの範囲で箔状のものを用いることができる。 As the current collector layer 101 used for manufacturing the battery negative electrode 100 according to the present embodiment, for example, a normal current collector that can be used for a battery can be used.
When the battery is a lithium ion battery, for example, copper, stainless steel, nickel, titanium or an alloy thereof can be used as the negative electrode current collector, and among these, copper is particularly preferable.
The shape of the current collector is not particularly limited. For example, a foil-like material having a thickness of 0.001 to 0.5 mm can be used.
　本実施形態に係る負極活物質層１０３の厚みや密度は、電池の使用用途等に応じて適宜決定されるため特に限定されず、一般的に公知の情報に準じて設定することができる。 The thickness and density of the negative electrode active material layer 103 according to the present embodiment are not particularly limited because they are appropriately determined in accordance with the use and the like of the battery, and can be set according to generally known information.
＜電池用負極電極の製造方法＞
　次に、本実施形態に係る電池用負極電極１００の製造方法について説明する。
　本実施形態に係る電池用負極電極１００の製造方法は、本実施形態に係る負極製造用ペーストの製造方法により得られた負極製造用ペーストを集電体層１０１に塗工して乾燥し、水系媒体を除去することによって、集電体層１０１上に負極活物質層１０３を形成する工程を含む。これにより集電体層１０１と負極活物質層１０３との接着性に優れた電池用負極電極１００を安定的に得ることができる。 <Method of Manufacturing Negative Electrode for Battery>
Next, a method of manufacturing the battery negative electrode 100 according to the present embodiment will be described.
In the method of manufacturing the battery negative electrode 100 according to the present embodiment, the negative electrode manufacturing paste obtained by the method of manufacturing the negative electrode manufacturing paste according to the present embodiment is applied to the current collector layer 101 and dried. A step of forming the negative electrode active material layer 103 on the current collector layer 101 by removing the medium is included. Thus, the battery negative electrode 100 having excellent adhesion between the current collector layer 101 and the negative electrode active material layer 103 can be stably obtained.
　すなわち、本実施形態に係る電池用負極電極１００は、本実施形態に係る負極製造用ペーストを負極集電体層１０１上に塗布して乾燥し、水系媒体を除去することにより集電体層１０１上に負極活物質層１０３を形成することにより得ることができる。 That is, the negative electrode for battery 100 according to the present embodiment applies the paste for producing a negative electrode according to the present embodiment on the negative electrode current collector layer 101 and dries it, and then the aqueous medium is removed. It can be obtained by forming the negative electrode active material layer 103 thereon.
　本実施形態に係る負極製造用ペーストを集電体層１０１上に塗布する方法は、一般的に公知の方法を用いることができる。例えば、リバースロール法、ダイレクトロール法、ドクターブレード法、ナイフ法、エクストルージョン法、カーテン法、グラビア法、バー法、ディップ法およびスクイーズ法等を挙げることができる。 As a method of applying the paste for negative electrode production according to the present embodiment on the current collector layer 101, generally known methods can be used. For example, reverse roll method, direct roll method, doctor blade method, knife method, extrusion method, curtain method, gravure method, bar method, dip method, squeeze method and the like can be mentioned.
　本実施形態に係る負極製造用ペーストは、集電体層１０１の片面のみに塗布しても両面に塗布してもよい。集電体層１０１の両面に塗布する場合は、片面ずつ逐次でも、両面同時に塗布してもよい。また、集電体層１０１の表面に連続で、あるいは、間欠で塗布してもよい。塗布層の厚さや長さ、幅は、電池の大きさに応じて、適宜決定することができる。 The paste for manufacturing a negative electrode according to the present embodiment may be applied to only one side of the current collector layer 101 or may be applied to both sides. In the case of coating on both sides of the current collector layer 101, one side may be sequentially applied, or both sides may be applied simultaneously. In addition, it may be applied to the surface of the current collector layer 101 continuously or intermittently. The thickness, length, and width of the coating layer can be appropriately determined according to the size of the battery.
　塗布した負極製造用ペーストの乾燥方法は、一般的に公知の方法を用いることができる。例えば、熱風、真空、赤外線、遠赤外線、電子線および低温風を単独あるいは組み合わせて用いることができる。乾燥温度は、例えば、３０℃以上３５０℃以下の範囲である。 A commonly known method can be used to dry the applied paste for negative electrode production. For example, hot air, vacuum, infrared, far infrared, electron beam and low temperature air can be used alone or in combination. The drying temperature is, for example, in the range of 30 ° C. or more and 350 ° C. or less.
　本実施形態に係る電池用負極電極１００は、必要に応じてプレスしてもよい。プレスの方法としては、一般的に公知の方法を用いることができる。例えば、金型プレス法やカレンダープレス法等が挙げられる。プレス圧は特に限定されないが、例えば、０．２～３ｔ／ｃｍ２の範囲である。 The battery negative electrode 100 according to the present embodiment may be pressed as necessary. As a method of pressing, generally known methods can be used. For example, a die press method, a calendar press method, etc. may be mentioned. The pressing pressure is not particularly limited, but is, for example, in the range of 0.2 to 3 t / cm 2 .
　本実施形態に係る電池用負極電極１００の厚みや密度は、電池の使用用途等に応じて適宜決定されるため特に限定されず、一般的に公知の情報に準じて設定することができる。 The thickness and density of the battery negative electrode 100 according to the present embodiment are not particularly limited because they are appropriately determined according to the use and the like of the battery, and can be set according to generally known information.
＜電池＞
　つづいて、本実施形態に係る電池１５０について説明する。図２は、本発明に係る実施形態の電池１５０の構造の一例を示す断面図である。 <Battery>
Subsequently, the battery 150 according to the present embodiment will be described. FIG. 2 is a cross-sectional view showing an example of the structure of the battery 150 according to the embodiment of the present invention.
　本実施形態に係る電池１５０は、正極１２０と、電解質１１０と、負極１３０とを少なくとも備え、負極１３０が本実施形態に係る電池用負極電極１００を含む。また、本実施形態に係る電池１５０は、必要に応じてセパレーターを含んでもよい。
　本実施形態に係る電池１５０は、負極１３０が本実施形態に係る電池用負極電極１００を含むため、電池を組み立てる際の負極活物質層の粉落ちが抑制されており、電池の品質や電池のサイクル特性等が良好である。
　本実施形態に係る電池１５０は公知の方法に準じて作製することができる。
　電極は、例えば、積層体や捲回体を使用できる。外装体としては、金属外装体やアルミラミネート外装体を適宜使用できる。電池の形状は、コイン型、ボタン型、シート型、円筒型、角型、扁平型等いずれの形状であってもよい。 A battery 150 according to the present embodiment includes at least a positive electrode 120, an electrolyte 110, and a negative electrode 130, and the negative electrode 130 includes the battery negative electrode 100 according to the present embodiment. In addition, the battery 150 according to the present embodiment may include a separator as needed.
In the battery 150 according to the present embodiment, since the negative electrode 130 includes the battery negative electrode 100 according to the present embodiment, powder removal of the negative electrode active material layer when assembling the battery is suppressed, and battery quality and battery The cycle characteristics etc. are good.
The battery 150 according to the present embodiment can be manufactured according to a known method.
As the electrode, for example, a laminate or a wound body can be used. As an exterior body, a metal exterior body and an aluminum laminate exterior body can be used suitably. The shape of the battery may be any shape such as coin type, button type, sheet type, cylindrical type, square type and flat type.
　電池の正極１２０は、公知の製造方法により製造することができる。例えば、正極活物質と、バインダーとを少なくとも含み、さらに必要に応じて導電助剤、増粘剤を含んだペーストを正極集電体に塗布・乾燥等の方法を用いて製造したものが挙げられる。 The positive electrode 120 of the battery can be manufactured by a known manufacturing method. For example, a paste containing at least a positive electrode active material and a binder, and, if necessary, a conductive auxiliary agent and a thickener, may be applied to a positive electrode current collector and manufactured using a method such as drying .
　正極活物質としては電池の正極に使用可能な通常の正極活物質であれば特に限定されない。上記電池がリチウムイオン電池の場合、例えば、リチウムニッケル複合酸化物、リチウムコバルト複合酸化物、リチウムマンガン複合酸化物、リチウム－マンガン－ニッケル複合酸化物等のリチウムと遷移金属との複合酸化物；ＴｉＳ２、ＦｅＳ、ＭｏＳ２等の遷移金属硫化物；ＭｎＯ、Ｖ２Ｏ５、Ｖ６Ｏ１３、ＴｉＯ２等の遷移金属酸化物、オリビン型リチウムリン酸化物等が挙げられる。
　オリビン型リチウムリン酸化物は、例えば、Ｍｎ、Ｃｒ、Ｃｏ、Ｃｕ、Ｎｉ、Ｖ、Ｍｏ、Ｔｉ、Ｚｎ、Ａｌ、Ｇａ、Ｍｇ、Ｂ、Ｎｂ、およびＦｅよりなる群のうちの少なくとも１種の元素と、リチウムと、リンと、酸素とを含んでいる。これらの化合物はその特性を向上させるために一部の元素を部分的に他の元素に置換したものであってもよい。 The positive electrode active material is not particularly limited as long as it is a normal positive electrode active material usable for the positive electrode of the battery. When the above battery is a lithium ion battery, for example, a composite oxide of lithium and a transition metal such as lithium nickel composite oxide, lithium cobalt composite oxide, lithium manganese composite oxide, lithium-manganese-nickel composite oxide; TiS 2 , transition metal sulfides such as FeS and MoS 2 ; transition metal oxides such as MnO, V 2 O 5 , V 6 O 13 , TiO 2 , and olivine-type lithium phosphorus oxide.
The olivine-type lithium phosphorus oxide is, for example, at least one member of the group consisting of Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg, B, Nb, and Fe. It contains elements, lithium, phosphorus and oxygen. These compounds may be obtained by partially replacing some elements with other elements in order to improve their properties.
　これらの中でも、オリビン型リチウム鉄リン酸化物、リチウムコバルト複合酸化物、リチウムニッケル複合酸化物、リチウムマンガン複合酸化物、リチウム－マンガン－ニッケル複合酸化物が好ましい。これらの正極活物質は作用電位が高いことに加えて容量も大きく、大きなエネルギー密度を有する。正極活物質は１種単独で使用してもよいし、２種以上を組み合わせて使用してもよい。 Among these, olivine-type lithium iron phosphorus oxide, lithium cobalt composite oxide, lithium nickel composite oxide, lithium manganese composite oxide, and lithium-manganese-nickel composite oxide are preferable. These positive electrode active materials have large capacity in addition to high action potential and large energy density. The positive electrode active material may be used singly or in combination of two or more.
　正極に用いられるバインダー樹脂は用途に応じて適宜選択される。例えば、溶媒に溶解可能なフッ素系バインダー樹脂や、水に分散可能な水系バインダー等を使用することができる。 The binder resin used for the positive electrode is appropriately selected according to the application. For example, a fluorine-based binder resin that can be dissolved in a solvent, an aqueous binder that can be dispersed in water, or the like can be used.
　フッ素系バインダー樹脂としては電極成形が可能であり、十分な電気化学的安定性を有していれば特に限定されないが、例えば、ポリフッ化ビニリデン系樹脂、フッ素ゴム等が挙げられる。これらのフッ素系バインダー樹脂は一種単独で用いてもよく、二種以上を組み合わせて用いてもよい。これらの中でも、ポリフッ化ビニリデン系樹脂が好ましい。フッ素系バインダー樹脂は、例えば、Ｎ－メチル-ピロリドン（ＮＭＰ）等の溶媒に溶解させて使用することができる。 The fluorine-based binder resin is not particularly limited as long as it can be formed into an electrode and has sufficient electrochemical stability, and examples thereof include polyvinylidene fluoride resins and fluororubbers. These fluorine-based binder resins may be used alone or in combination of two or more. Among these, polyvinylidene fluoride resins are preferable. The fluorine-based binder resin can be used, for example, by dissolving it in a solvent such as N-methyl-pyrrolidone (NMP).
　また、水系バインダー樹脂、増粘剤、導電助剤としては、上記の本実施形態に係る負極製造用ペーストを構成する各材料と同じものを用いることができる。 In addition, as the aqueous binder resin, the thickener, and the conductive additive, the same materials as those constituting the paste for producing a negative electrode according to the present embodiment can be used.
　正極集電体としては、アルミニウム、ステンレス鋼、ニッケル、チタンまたはこれらの合金等を用いることができ、これらの中でもアルミニウムが特に好ましい。 As the positive electrode current collector, aluminum, stainless steel, nickel, titanium or an alloy thereof can be used. Among these, aluminum is particularly preferable.
　電池の電解液中の電解質としては、公知のリチウム塩がいずれも使用でき、活物質の種類に応じて選択すればよい。例えば、ＬｉＣｌＯ４、ＬｉＢＦ６、ＬｉＰＦ６、ＬｉＣＦ３ＳＯ３、ＬｉＣＦ３ＣＯ２、ＬｉＡｓＦ６、ＬｉＳｂＦ６、ＬｉＢ１０Ｃｌ１０、ＬｉＡｌＣｌ４、ＬｉＣｌ、ＬｉＢｒ、ＬｉＢ（Ｃ２Ｈ５）４、ＣＦ３ＳＯ３Ｌｉ、ＣＨ３ＳＯ３Ｌｉ、ＬｉＣＦ３ＳＯ３、ＬｉＣ４Ｆ９ＳＯ３、Ｌｉ（ＣＦ３ＳＯ２）２Ｎ、低級脂肪酸カルボン酸リチウム等が挙げられる。 Any known lithium salt can be used as the electrolyte in the electrolytic solution of the battery, and it may be selected according to the type of active material. For example, LiClO 4, LiBF 6, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiB 10 Cl 10, LiAlCl 4, LiCl, LiBr, LiB (C 2 H 5) 4, CF 3 SO 3 Li, CH 3 SO 3 Li, LiCF 3 SO 3 , LiC 4 F 9 SO 3 , Li (CF 3 SO 2 ) 2 N, lithium lower fatty acid carboxylate and the like can be mentioned.
　電解質を溶解する溶媒としては、電解質を溶解させる液体成分として通常用いられるものであれば特に限定されるものではなく、エチレンカーボネート（ＥＣ）、プロピレンカーボネート（ＰＣ）、ブチレンカーボネート（ＢＣ）、ジメチルカーボネート（ＤＭＣ）、ジエチルカーボネート（ＤＥＣ）、メチルエチルカーボネート（ＭＥＣ）、ビニレンカーボネート（ＶＣ）等のカーボネート類；γ－ブチロラクトン、γ－バレロラクトン等のラクトン類；トリメトキシメタン、１，２－ジメトキシエタン、ジエチルエーテル、２－エトキシエタン、テトラヒドロフラン、２－メチルテトラヒドロフラン等のエーテル類；ジメチルスルホキシド等のスルホキシド類；１，３－ジオキソラン、４－メチル－１，３－ジオキソラン等のオキソラン類；アセトニトリル、ニトロメタン、ホルムアミド、ジメチルホルムアミド等の含窒素類；ギ酸メチル、酢酸メチル、酢酸エチル、酢酸ブチル、プロピオン酸メチル、プロピオン酸エチル等の有機酸エステル類；リン酸トリエステルやジグライム類；トリグライム類；スルホラン、メチルスルホラン等のスルホラン類；３－メチル－２－オキサゾリジノン等のオキサゾリジノン類；１，３－プロパンスルトン、１，４－ブタンスルトン、ナフタスルトン等のスルトン類等が挙げられる。これらは、１種単独で使用してもよいし、２種以上を組み合わせて使用してもよい。 The solvent for dissolving the electrolyte is not particularly limited as long as it is generally used as a liquid component for dissolving the electrolyte, and ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), vinylene carbonate (VC) and other carbonates; γ-butyrolactone, γ-valerolactone and other lactones; trimethoxymethane, 1,2-dimethoxyethane Ethers such as diethyl ether, 2-ethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, etc. Sulfoxides such as dimethylsulfoxide etc. Oxolanes such as 1,3-dioxolane, 4-methyl-1,3-dioxolane Kinds of nitrogen; Nitrogenous compounds such as acetonitrile, nitromethane, formamide, dimethylformamide, etc .; Organic acid esters such as methyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl propionate, ethyl propionate; phosphoric acid triesters and diglymes; Triligmes; sulfolanes such as sulfolane and methyl sulfolane; oxazolidinones such as 3-methyl-2-oxazolidinone; and sultones such as 1,3-propane sultone, 1,4-butane sultone and naphtha sultone. These may be used singly or in combination of two or more.
　セパレーターとしては、例えば、多孔性セパレーターが挙げられる。セパレーターの形態は、膜、フィルム、不織布等が挙げられる。
　多孔性セパレーターとしては、例えば、ポリプロピレン系、ポリエチレン系等のポリオレフィン系多孔性セパレーター；ポリビニリデンフルオリド、ポリエチレンオキシド、ポリアクリロニトリル、ポリビニリデンフルオリドヘキサフルオロプロピレン共重合体等により形成された多孔性セパレーターが挙げられる。 As a separator, a porous separator is mentioned, for example. The form of the separator includes a membrane, a film, a non-woven fabric and the like.
Examples of the porous separator include polyolefin-based porous separators such as polypropylene and polyethylene; porous separators formed of polyvinylidene fluoride, polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride hexafluoropropylene copolymer, etc. Can be mentioned.
　以上、本発明の実施形態について述べたが、これらは本発明の例示であり、上記以外の様々な構成を採用することもできる。
　また、本発明は前述の実施形態に限定されるものではなく、本発明の目的を達成できる範囲での変形、改良等は本発明に含まれるものである。 As mentioned above, although embodiment of this invention was described, these are the illustrations of this invention, and various structures other than the above can also be employ | adopted.
Further, the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the range in which the object of the present invention can be achieved are included in the present invention.
　以下、本発明を実施例および比較例により説明するが、本発明はこれらに限定されるものではない。 Hereinafter, the present invention will be described by way of Examples and Comparative Examples, but the present invention is not limited thereto.
（実施例１）
＜水系負極製造用ペーストの作製＞
（Ａ）乾式混合工程
　遊星運動型プラネタリーミキサー（釜の大きさ：２００Ｌ）に、表面が非晶質の炭素で被覆された黒鉛（平均粒子径ｄ５０：１６μｍ、窒素吸着ＢＥＴ法による比表面積：３．４ｍ２／ｇ）９６０ｇと、カルボキシメチルセルロース粉末（日本製紙社製サンローズ（登録商標）のＭＡＣシリーズ、エーテル化度：０．７３、重量平均分子量Ｍｗ：３０００００（ポリエチレングリコール換算値））１０ｇと、導電助剤として約３０ｎｍの１次粒子が連鎖状に凝集したカーボンブラック（窒素吸着ＢＥＴ法による比表面積：６０ｍ２／ｇ）１０ｇとを投入した。次いで、自転速度：０．２６ｍ／ｓｅｃ、公転速度：０．０８ｍ／ｓｅｃ、温度：２０℃の条件下で２０分間乾式混合をおこない、粉体混合物を得た。ここで、自転速度および公転速度は、遊星運動型プラネタリーミキサーのブレードの線速度である。
　以下、平均粒子径ｄ５０はＭｉｃｒｏｔｒａｃ社製、ＭＴ３０００装置により測定し、比表面積は、Ｑｕａｎｔａｃｈｒｏｍｅ　Ｃｏｒｐｏｒａｔｉｏｎ社製、Ｑｕａｎｔａ　Ｓｏｒｂを用いて、窒素吸着ＢＥＴ法にて求めた。 Example 1
<Preparation of paste for aqueous negative electrode production>
(A) Dry mixing step Graphite (average particle diameter d 50 : 16 μm, specific surface area by nitrogen adsorption BET method) whose surface is coated with amorphous carbon on a planetary motion type planetary mixer (size of kettle: 200 L) : 3.4 m 2 / g) 960 g and carboxymethylcellulose powder (MAC series of Sun Rose (registered trademark) manufactured by Nippon Paper Industries, degree of etherification: 0.73, weight average molecular weight Mw: 300000 (polyethylene glycol equivalent value)) 10 g and 10 g of carbon black (specific surface area by nitrogen adsorption BET method: 60 m 2 / g) in which primary particles of about 30 nm were aggregated in a chain as a conductive aid were charged. Next, dry mixing was performed for 20 minutes under the conditions of a rotation speed of 0.26 m / sec, a rotation speed of 0.08 m / sec, and a temperature of 20 ° C. to obtain a powder mixture. Here, the rotation speed and revolution speed are linear speeds of blades of a planetary motion type planetary mixer.
The average particle diameter d 50 is measured by MT 3000, manufactured by Microtrac, and the specific surface area is determined by nitrogen adsorption BET method using Quanta Sorb manufactured by Quantachrome Corporation.
　ここで、表面が非晶質の炭素で被覆された黒鉛は以下のように作製した。
　平均粒子径ｄ５０が１６μｍ、比表面積が３．４ｍ２／ｇの天然黒鉛を核材として使用した。
　この天然黒鉛粉末９９．０質量部と、石炭系ピッチ粉末１．０質量部とを、Ｖブレンダーを用いた単純混合により固相で混合した。得られた混合粉末を黒鉛るつぼに入れ、窒素気流下１３００℃で１時間熱処理して、表面が非晶質の炭素で被覆された黒鉛を得た。 Here, graphite whose surface was coated with amorphous carbon was produced as follows.
Natural graphite having an average particle diameter d 50 of 16 μm and a specific surface area of 3.4 m 2 / g was used as a core material.
99.0 parts by mass of this natural graphite powder and 1.0 parts by mass of coal-based pitch powder were mixed in a solid phase by simple mixing using a V blender. The obtained mixed powder was placed in a graphite crucible and heat-treated at 1300 ° C. for 1 hour in a nitrogen stream to obtain graphite whose surface was coated with amorphous carbon.
（Ｂ１）なじませ工程
　次いで、上記乾式混合工程（Ａ）が終了した遊星運動型プラネタリーミキサーに、得られるペースト前駆体の固形分濃度が７１質量％になるように水を添加した。その後、自転速度：０．１５ｍ／ｓｅｃ、公転速度：０．０４ｍ／ｓｅｃ、温度：２０℃の条件下で２分間大気圧の条件下で２分間湿式混合をおこない、粉体混合物に水をなじませた。ここで、自転速度および公転速度は、遊星運動型プラネタリーミキサーのブレードの線速度である。 (B1) Adaptation Step Subsequently, water was added to the planetary motion type planetary mixer in which the dry mixing step (A) was completed such that the solid content concentration of the obtained paste precursor was 71% by mass. After that, wet mixing is performed for 2 minutes under the conditions of the rotation speed: 0.15 m / sec, the rotation speed: 0.04 m / sec, the temperature: 20 ° C. for 2 minutes, and the powder mixture is treated with water. I did not. Here, the rotation speed and revolution speed are linear speeds of blades of a planetary motion type planetary mixer.
（Ｂ２）第１の固練り工程
　次いで、自転速度：０．２６ｍ／ｓｅｃ、公転速度：０．０８ｍ／ｓｅｃ、温度：２０℃、大気圧の条件下で３０分間湿式混合をおこなった。ここで、自転速度および公転速度は、遊星運動型プラネタリーミキサーのブレードの線速度である。 (B2) First Hard-Mixing Step Next, wet mixing was performed for 30 minutes under the conditions of an rotation speed of 0.26 m / sec, a rotation speed of 0.08 m / sec, a temperature of 20 ° C. and atmospheric pressure. Here, the rotation speed and revolution speed are linear speeds of blades of a planetary motion type planetary mixer.
（Ｂ３）第２の固練り工程
　次いで、上記第１の固練り工程（Ｂ２）が終了した遊星運動型プラネタリーミキサーに、得られるペースト前駆体の固形分濃度が６３質量％になるように水を添加し、自転速度、公転速度、温度は上記第１の固練り工程（Ｂ２）と同じ条件にしたまま、大気圧の条件下で３０分間湿式混合をおこない、負極製造用ペースト前駆体を得た。
（Ｃ）負極製造用ペースト調製工程
　次いで、水系バインダー樹脂としてスチレン・ブタジエン共重合体ゴム（ＳＢＲ）を水に分散した固形分濃度４０質量％のＳＢＲエマルジョン水溶液を調製した。得られたＳＢＲエマルジョン水溶液５０ｇを、固練り工程が終了した遊星運動型プラネタリーミキサーに添加した。
　その後、自転速度：０．５２ｍ／ｓｅｃ、公転速度：０．１５ｍ／ｓｅｃ、温度：２０℃の条件下で４０分間湿式混合をおこなった。ここで、自転速度および公転速度は、遊星運動型プラネタリーミキサーのブレードの線速度である。
（Ｄ）脱泡工程
　次いで、真空脱泡を行い、負極製造用ペーストを得た。
　なお、負極製造用ペーストの最終的な固形分濃度は、負極製造用ペーストを調製する工程（Ｃ）において水を添加することによって５１質量％に調整した。 (B3) Second Hard-Mixing Step Next, in the planetary motion type planetary mixer where the above-mentioned first hard-mixing step (B2) is completed, water is adjusted so that the solid content concentration of the obtained paste precursor becomes 63 mass%. The mixture was wet mixed under the conditions of atmospheric pressure for 30 minutes while maintaining the rotation speed, revolution speed and temperature under the same conditions as the first solidifying step (B2) to obtain a paste precursor for negative electrode production. The
(C) Paste preparation process for negative electrode manufacture Then, the SBR emulsion aqueous solution of solid content concentration 40 mass% which disperse | distributed the styrene butadiene copolymer rubber (SBR) as water-based binder resin in water was prepared. 50 g of the obtained aqueous solution of SBR emulsion was added to the planetary motion type planetary mixer on which the solidifying process was completed.
Thereafter, wet mixing was performed for 40 minutes under the conditions of a rotation speed of 0.52 m / sec, a rotation speed of 0.15 m / sec, and a temperature of 20 ° C. Here, the rotation speed and revolution speed are linear speeds of blades of a planetary motion type planetary mixer.
(D) Defoaming Step Subsequently, vacuum degassing was performed to obtain a paste for producing a negative electrode.
The final solid content concentration of the paste for negative electrode production was adjusted to 51% by mass by adding water in the step (C) of preparing the paste for negative electrode production.
　＜負極の作製＞
　得られた負極製造用ペーストを集電体層である銅箔の両面にダイコータを用いて塗布し、乾燥した。次いで、得られた電極をプレスして、負極を得た。 <Fabrication of negative electrode>
The obtained paste for negative electrode production was applied to both sides of a copper foil as a current collector layer using a die coater, and dried. Then, the obtained electrode was pressed to obtain a negative electrode.
＜評価＞
（１）負極製造用ペーストの粘度測定
　Ｂ型粘度計（ブルックフィールド社製、回転粘度計）を用いて、２５℃、せん断速度３．４ｓ－１の条件で負極製造用ペーストの粘度を測定した。 <Evaluation>
(1) Viscosity measurement of paste for negative electrode production The viscosity of the paste for negative electrode production was measured under the conditions of 25 ° C. and a shear rate of 3.4 s −1 using a B-type viscometer (rotation viscometer manufactured by Brookfield Co., Ltd.) .
（２）剥離強度試験
　以下の手順により、得られた負極の剥離強度を測定した。負極を幅２０ｍｍ、長さ１０ｃｍにわたって切り取り、負極の片面を両面テープが張られた板に貼り付けた。次いで、板を固定し、負極を１００ｍｍ／ｍｉｎの速度で９０°方向に剥離した。そのときの剥離強度（ｍＮ／ｍｍ）を３回測定し、その平均値を剥離強度とした。 (2) Peeling Strength Test The peeling strength of the obtained negative electrode was measured by the following procedure. The negative electrode was cut over a width of 20 mm and a length of 10 cm, and one side of the negative electrode was attached to a plate on which a double-sided tape was applied. Then, the plate was fixed, and the negative electrode was peeled in the direction of 90 ° at a speed of 100 mm / min. The peel strength (mN / mm) at that time was measured three times, and the average value was taken as the peel strength.
　得られた評価結果を表１に示す。 The obtained evaluation results are shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
（実施例２～１５、比較例１～６）
　なじませ工程（Ｂ１）の有無、第１の固練り工程（Ｂ２）および第２の固練り工程（Ｂ３）の固形分濃度、並びに混合時間を表１に示す値に変化させた以外は実施例１と同様にそれぞれ水系負極製造用ペーストを調製し、各評価をそれぞれおこなった。得られた結果を表１に示す。 (Examples 2 to 15, Comparative Examples 1 to 6)
Example except that the solid concentration of the first solidifying step (B2) and the second solidifying step (B3) and the mixing time were changed to the values shown in Table 1 The paste for water system negative electrode manufacture was prepared similarly to 1, respectively, and each evaluation was performed, respectively. The obtained results are shown in Table 1.
　この出願は、２０１７年１１月２９日に出願された日本出願特願２０１７－２２８６６５号を基礎とする優先権を主張し、その開示の全てをここに取り込む。 This application claims priority based on Japanese Patent Application No. 2017-228665 filed on Nov. 29, 2017, the entire disclosure of which is incorporated herein.

Claims (18)

  1. 　負極活物質および増粘剤を少なくとも含む複数の粉末状物質を紛体状態で乾式混合することにより、前記負極活物質および前記増粘剤を少なくとも含む混合物を調製する工程（Ａ）と、
    　前記混合物中に、水系媒体および水系バインダーを含むエマルジョン水溶液から選択される一種または二種以上の液体成分を添加して湿式混合することにより、ペースト前駆体を調製する工程（Ｂ）と、
    　前記ペースト前駆体中に、前記水系媒体および前記水系バインダーを含むエマルジョン水溶液から選択される一種または二種以上の液体成分をさらに添加して湿式混合することにより、負極製造用ペーストを調製する工程（Ｃ）と、
    を含む、負極製造用ペーストの製造方法であって、
    　前記工程（Ｂ）は、第１の固練り工程（Ｂ２）と第２の固練り工程（Ｂ３）とを少なくとも含み、
    　前記第１の固練り工程（Ｂ２）における固形分濃度が６８質量％以上７９質量％以下であり、前記第２の固練り工程（Ｂ３）における固形分濃度が５９質量％以上６６質量％以下である、負極製造用ペーストの製造方法。     Preparing a mixture including at least the negative electrode active material and the thickener by dry-mixing a plurality of powdery materials including at least a negative electrode active material and a thickener in a powder state;
    Step (B) of preparing a paste precursor by adding one or two or more kinds of liquid components selected from an aqueous solution of an aqueous medium and an aqueous binder to the mixture and wet mixing them;
    A step of preparing a paste for negative electrode production by further adding one or two or more kinds of liquid components selected from the aqueous medium and the aqueous emulsion containing the aqueous binder to the paste precursor and wet mixing C) and
    A method for producing a paste for producing a negative electrode, comprising
    The step (B) includes at least a first solidifying step (B2) and a second solidifying step (B3),
    The solid content concentration in the first solidifying step (B2) is 68% by mass to 79% by mass, and the solid content concentration in the second solidifying step (B3) is 59% by mass to 66% by mass There is a method for producing a paste for producing a negative electrode.
  2. 　請求項１に記載の負極製造用ペーストの製造方法において、
    　前記第１の固練り工程（Ｂ２）における固形分濃度が７１質量％以上である、負極製造用ペーストの製造方法。     In the method of producing a paste for producing a negative electrode according to claim 1,
    The manufacturing method of the paste for negative electrode manufacture whose solid content concentration in the said 1st firming process (B2) is 71 mass% or more.
  3. 　請求項１または２に記載の負極製造用ペーストの製造方法において、
    　前記第１の固練り工程（Ｂ２）における固形分濃度が７７質量％以下である、負極製造用ペーストの製造方法。     In the manufacturing method of the paste for negative electrode manufacture of Claim 1 or 2,
    The manufacturing method of the paste for negative electrode manufacture whose solid content concentration in the said 1st firming process (B2) is 77 mass% or less.
  4. 　請求項１乃至３のいずれか一項に記載の負極製造用ペーストの製造方法において、
    　前記第１の固練り工程（Ｂ２）と前記第２の固練り工程（Ｂ３）における前記湿式混合の自転速度を０．１０ｍ／ｓｅｃ以上２．０ｍ／ｓｅｃ以下の範囲内に設定する、負極製造用ペーストの製造方法。     In the manufacturing method of the paste for negative electrode manufacture as described in any one of Claims 1 thru | or 3,
    Negative electrode production, wherein the rotation speed of the wet mixing in the first solidifying step (B2) and the second solidifying step (B3) is set in the range of 0.10 m / sec to 2.0 m / sec. Paste production method.
  5. 　請求項１乃至４のいずれか一項に記載の負極製造用ペーストの製造方法において、
    　前記第１の固練り工程（Ｂ２）と前記第２の固練り工程（Ｂ３）における前記湿式混合の公転速度を０．０１ｍ／ｓｅｃ以上１．０ｍ／ｓｅｃ以下の範囲内に設定する、負極製造用ペーストの製造方法。     In the manufacturing method of the paste for negative electrode manufacture as described in any one of Claim 1 thru | or 4,
    Anode production, wherein the revolution speed of the wet mixing in the first solidifying step (B2) and the second solidifying step (B3) is set in the range of 0.01 m / sec or more and 1.0 m / sec or less Paste production method.
  6. 　請求項１乃至５のいずれか一項に記載の負極製造用ペーストの製造方法において、
    　前記工程（Ｂ）は、前記第１の固練り工程（Ｂ２）と前記第２の固練り工程（Ｂ３）の前に行う、なじませ工程（Ｂ１）をさらに含み、
    　前記第１の固練り工程（Ｂ２）と前記第２の固練り工程（Ｂ３）における前記湿式混合の自転速度を、前記なじませ工程（Ｂ１）における湿式混合の自転速度よりも高く設定する、負極製造用ペーストの製造方法。     In the manufacturing method of the paste for negative electrode manufacture as described in any one of Claims 1 thru | or 5,
    The step (B) further includes a blending step (B1) which is performed before the first solidifying step (B2) and the second solidifying step (B3),
    A negative electrode in which the rotation speed of the wet mixing in the first solidifying step (B2) and the second solidifying step (B3) is set higher than that of the wet mixing in the kneading step (B1) Method of producing paste for production.
  7. 　請求項１乃至６のいずれか一項に記載の負極製造用ペーストの製造方法において、
    　前記負極製造用ペーストのｐＨが６．０以上８．０以下である、負極製造用ペーストの製造方法。     In the manufacturing method of the paste for negative electrode manufacture as described in any one of Claims 1 thru | or 6,
    The manufacturing method of the paste for negative electrode manufacture whose pH of the paste for said negative electrode production is 6.0-8.0.
  8. 　請求項１乃至７のいずれか一項に記載の負極製造用ペーストの製造方法において、
    　前記増粘剤がセルロース系水溶性高分子を含むものである、負極製造用ペーストの製造方法。     In the manufacturing method of the paste for negative electrode manufacture as described in any one of Claims 1 thru | or 7,
    The manufacturing method of the paste for negative electrode manufacture in which the said thickener contains a cellulose type water soluble polymer.
  9. 　請求項８に記載の負極製造用ペーストの製造方法において、
    　前記セルロース系水溶性高分子のエーテル化度が０．５０以上１．０以下である、負極製造用ペーストの製造方法。     In the method of producing a paste for producing a negative electrode according to claim 8,
    The manufacturing method of the paste for negative electrode manufacture whose etherification degree of the said cellulose water-soluble polymer is 0.50-1.0.
  10. 　請求項８または９に記載の負極製造用ペーストの製造方法において、
    　前記セルロース系水溶性高分子の重量平均分子量Ｍｗが１０００００以上である、負極製造用ペーストの製造方法。     In the method for producing a paste for producing a negative electrode according to claim 8 or 9,
    The manufacturing method of the paste for negative electrode manufacture whose weight average molecular weight Mw of the said cellulose water soluble polymer is 100,000 or more.
  11. 　請求項１乃至１０のいずれか一項に記載の負極製造用ペーストの製造方法において、
    　前記水系バインダーがスチレン・ブタジエン共重合体ゴムを含むものである、負極製造用ペーストの製造方法。     The method for producing a paste for producing a negative electrode according to any one of claims 1 to 10.
    The manufacturing method of the paste for negative electrode manufacture whose said water-based binder contains a styrene butadiene copolymer rubber.
  12. 　請求項１乃至１１のいずれか一項に記載の負極製造用ペーストの製造方法において、
    　当該負極製造用ペーストの固形分の全量を１００質量部としたとき、
    　前記負極活物質の含有量が７０質量部以上９９．９７質量部以下であり、
    　前記増粘剤の含有量が０．０１質量部以上１０．０質量部以下であり、
    　前記水系バインダーの含有量が０．０１質量部以上１０．０質量部以下である、負極製造用ペーストの製造方法。     The method for producing a paste for producing a negative electrode according to any one of claims 1 to 11.
    When the total amount of solid content of the paste for negative electrode production is 100 parts by mass,
    The content of the negative electrode active material is 70 parts by mass or more and 99.97 parts by mass or less,
    The content of the thickener is 0.01 parts by mass or more and 10.0 parts by mass or less,
    The manufacturing method of the paste for negative electrode manufacture whose content of the said water-based binder is 0.01 mass part or more and 10.0 mass parts or less.
  13. 　請求項１乃至１２のいずれか一項に記載の負極製造用ペーストの製造方法において、
    　前記負極活物質が炭素材料を含むものである、負極製造用ペーストの製造方法。     The method for producing a paste for producing a negative electrode according to any one of claims 1 to 12.
    The manufacturing method of the paste for negative electrode manufacture in which the said negative electrode active material contains a carbon material.
  14. 　請求項１乃至１３のいずれか一項に記載の負極製造用ペーストの製造方法において、
    　さらに、炭素材料を含む材料で構成された導電助剤を含む、負極製造用ペーストの製造方法。     In the method for producing a paste for producing a negative electrode according to any one of claims 1 to 13,
    Furthermore, the manufacturing method of the paste for negative electrode manufacture containing the conductive support agent comprised with the material containing a carbon material.
  15. 　請求項１４に記載の負極製造用ペーストの製造方法において、
    　前記導電助剤の窒素吸着ＢＥＴ法による比表面積が５０ｍ２／ｇ以上である、負極製造用ペーストの製造方法。     In the method for producing a paste for producing a negative electrode according to claim 14,
    The manufacturing method of the paste for negative electrode manufacture whose specific surface area by nitrogen adsorption BET method of the said conductive support agent is 50 m < 2 > / g or more.
  16. 　集電体層と、前記集電体層の少なくとも一方の面に設けられ、かつ、請求項１乃至１５のいずれか一項に記載の負極製造用ペーストの製造方法により得られた負極製造用ペーストの固形分により形成された負極活物質層と、を含む電池用負極電極。 A paste for producing a negative electrode, provided on a current collector layer and at least one surface of the current collector layer, and obtained by the method for producing a paste for producing a negative electrode according to any one of claims 1 to 15. And a negative electrode active material layer formed of the solid content of the above.
  17. 　正極と、電解質と、負極とを少なくとも備えた電池であって、
    　前記負極が請求項１６に記載の電池用負極電極を含む電池。     A battery comprising at least a positive electrode, an electrolyte and a negative electrode,
    A battery comprising the battery negative electrode according to claim 16.
  18. 　請求項１乃至１５のいずれか一項に記載の負極製造用ペーストの製造方法により得られた負極製造用ペーストを集電体層に塗工して乾燥し、前記水系媒体を除去することによって、前記集電体層上に負極活物質層を形成する工程を含む電池用負極電極の製造方法。 A paste for negative electrode production obtained by the method for producing a negative electrode production paste according to any one of claims 1 to 15 is applied to a current collector layer, dried, and the aqueous medium is removed, The manufacturing method of the negative electrode for batteries containing the process of forming a negative electrode active material layer on the said collector layer.
PCT/JP2018/040535 2017-11-29 2018-10-31 Method for producing paste for negative electrode production, negative electrode for batteries, battery, and method for producing negative electrode for batteries WO2019107054A1 (en)

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