WO2009119553A1 - Method for production of electrode for hybrid capacitor - Google Patents

Method for production of electrode for hybrid capacitor Download PDF

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Publication number
WO2009119553A1
WO2009119553A1 PCT/JP2009/055767 JP2009055767W WO2009119553A1 WO 2009119553 A1 WO2009119553 A1 WO 2009119553A1 JP 2009055767 W JP2009055767 W JP 2009055767W WO 2009119553 A1 WO2009119553 A1 WO 2009119553A1
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WO
WIPO (PCT)
Prior art keywords
electrode
current collector
composite particles
binder
active material
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PCT/JP2009/055767
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French (fr)
Japanese (ja)
Inventor
敬太 戸倉
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日本ゼオン株式会社
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Priority to JP2010505656A priority Critical patent/JPWO2009119553A1/en
Publication of WO2009119553A1 publication Critical patent/WO2009119553A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their material
    • H01G11/50—Electrodes characterised by their material specially adapted for lithium-ion capacitors, e.g. for lithium-doping or for intercalation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/84—Processes for the manufacture of hybrid or EDL capacitors, or components thereof
    • H01G11/86—Processes for the manufacture of hybrid or EDL capacitors, or components thereof specially adapted for electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/04—Hybrid capacitors
    • H01G11/06—Hybrid capacitors with one of the electrodes allowing ions to be reversibly doped thereinto, e.g. lithium ion capacitors [LIC]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/26—Electrodes characterised by their structure, e.g. multi-layered, porosity or surface features
    • H01G11/28—Electrodes characterised by their structure, e.g. multi-layered, porosity or surface features arranged or disposed on a current collector; Layers or phases between electrodes and current collectors, e.g. adhesives
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/66—Current collectors
    • H01G11/70—Current collectors characterised by their structure
    • 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
    • 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
    • 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
    • Y02E60/13—Energy storage using capacitors

Definitions

  • the present invention relates to an electrode for a hybrid capacitor that is suitably used for a hybrid capacitor composed of a positive electrode made of a material capable of reversibly supporting lithium ions and / or anions and a negative electrode made of a material capable of reversibly supporting lithium ions. It relates to the manufacturing method.
  • Electrochemical elements such as lithium ion secondary batteries and electric double layer capacitors that are small and light, have high energy density, and can be repeatedly charged and discharged are rapidly expanding their demands by taking advantage of their characteristics.
  • Lithium ion secondary batteries have a relatively high energy density and are therefore used in fields such as mobile phones and notebook personal computers.
  • Electric double layer capacitors are used as memory backup compact power sources for personal computers and the like.
  • electric double layer capacitors are excellent in rapid charge / discharge characteristics, so that they have been used in construction machines such as excavators and cranes that require repeated charge / discharge.
  • the energy density of the electric double layer capacitor is about 3 to 4 Wh / liter, which is about two orders of magnitude smaller than that of the lithium ion secondary battery.
  • Hybrid capacitors using a Faraday reaction electrode for one of the two electrodes, the positive electrode and the negative electrode, and a non-Faraday reaction electrode for the other has been developed with the aim of achieving both a high energy density and a charge / discharge rate.
  • Hybrid capacitors are highly expected as electrochemical devices that combine safety, high capacity, and rapid charge / discharge.
  • Lithium ion secondary batteries have a high energy density, but have problems in output density, cycle characteristics, and safety.
  • the ion diffusion is accelerated by reducing the thickness of the electrode or increasing the porosity of the electrode to reduce the resistance.
  • the usage ratio of members that do not contribute to capacity such as separators and current collectors increases, the ratio of the electrodes occupying the cells decreases, and the energy density decreases.
  • the electrode is made porous, the amount of the active material filled in the cell is reduced, so that the energy density is lowered.
  • the power density is improved by reducing the particle size of the active material.
  • an electrode of a lithium ion secondary battery is manufactured by applying an electrode slurry containing an active material on a current collector.
  • the particle size of the active material is reduced, the fluidity of the slurry is deteriorated or the slurry concentration is reduced.
  • the coating speed cannot be increased.
  • the cycle characteristics as a battery fate with a Faraday reaction, in applications where charging and discharging are repeated, a method of using at a shallow charge / discharge depth is generally used, and an extra battery needs to be mounted.
  • lithium-containing composite oxides are generally used for the positive electrode, but the essential problems remain due to the instability of the crystal structure in the charged state.
  • Electric double layer capacitors have a high output density but a low energy density, and new carbon materials aimed at higher capacity have been developed as materials.
  • a proposal of alkali activated charcoal using potassium Japanese Unexamined Patent Publication No. 2004-47613 and an electric field activation treatment have been proposed (Japanese Unexamined Patent Publication No. 2002-25867).
  • these proposals still have problems in practical use due to the deterioration of cycle characteristics.
  • a current collector having protrusions is used to increase the energy density of the electric double layer capacitor (Japanese Patent Laid-Open No. 10-284349), or a metal fiber current collector is used to fill the current collector with the active material. (See Japanese Patent Laid-Open No.
  • a hybrid capacitor using a Faraday reaction electrode for one of the positive electrode and the negative electrode and a non-Faraday reaction electrode for the other has been attracting attention in order to achieve both high energy density and charge / discharge speed.
  • a carbon material capable of inserting and extracting lithium ions and to dope lithium ions in advance As a method of preliminarily occluding lithium ions in a carbon material that can occlude and desorb lithium ions, powdered lithium is mixed in advance with a carbon material powder that can occlude and desorb lithium ions, or lithium ions can be occluded and desorbed.
  • An electrode formed of a carbon material capable of inserting and extracting lithium ions and a binder is placed on one side of an electrolyte solution of a non-aqueous (organic) solvent containing lithium salt as an electrolyte, and a lithium metal electrode is placed on the other side
  • An electrochemical method in which an electric current is applied and lithium ions are occluded in a carbon material has been proposed, and a cell is formed using a current collector having a through hole.
  • a hybrid capacitor including a positive electrode made of a material capable of reversibly supporting lithium ions and / or anions and a negative electrode made of a material capable of reversibly supporting lithium ions, the negative electrode and / or the positive electrode
  • a method has been proposed in which lithium ions are doped into a negative electrode and / or a positive electrode in a cell by electrochemical contact between the lithium metal foil and the lithium metal foil.
  • An object of the present invention is to provide a method for efficiently producing a large number of electrodes for a hybrid capacitor that provides a low-resistance hybrid capacitor.
  • the present inventor gives a low-resistance hybrid capacitor by roll forming using a porous current collector capable of collectively doping lithium ions into the negative electrode and / or the positive electrode. It has been found that an electrode for a hybrid capacitor can be obtained. Further, a pressure device comprising a pair of rolls as a pressure device, a molding speed of 10 m / min or more in the step of forming the electrode layer, and a composite comprising an electrode active material bound by a binder as an electrode material It has been found that the resistance can be further reduced by using particles and setting the roll gap of the press roll, the opening area and the opening diameter of the porous collector to a specific range. The present inventor has completed the present invention based on these findings.
  • the electrode material is supplied to at least one surface of the porous current collector, and the electrode layer is formed on the porous current collector by pressurizing the porous current collector and the electrode material.
  • a method for manufacturing an electrode for a hybrid capacitor comprising a forming step.
  • a hybrid capacitor provided with the electrode for hybrid capacitors obtained by the said manufacturing method is provided.
  • the pressurization can be performed by a pressurization apparatus including a pair of rolls.
  • a pressurization apparatus including a pair of rolls.
  • rate in the process of forming the said electrode layer it can be 10 m / min or more.
  • the electrode material composite particles containing an electrode active material and a binder, and the electrode active material bound by the binder can be used.
  • the opening area of the porous current collector can be set in the range of 10 to 90 area%, and the opening diameter of the porous current collector can be set in the range of 0.1 to 10 ⁇ m.
  • the electrode material used in the present invention is used for obtaining an electrode for a hybrid capacitor.
  • the electrode material includes an electrode active material and a binder as essential components, and if necessary, a conductive material, a dispersion material, and Other additives and the like can be contained.
  • Electrode active material is a material that transfers electrons in the electrode.
  • Electrode active materials used for hybrid capacitor electrodes include positive electrodes and negative electrodes.
  • the electrode active material used for the positive electrode of the hybrid capacitor electrode may be any material that can reversibly carry lithium ions and anions such as tetrafluoroborate.
  • electrode active materials used in electric double layer capacitors can be widely used, and carbon allotropes are used.
  • those capable of forming an interface having a larger area with the same weight, that is, those having a large specific surface area are preferred.
  • the specific surface area is 30 m 2 / g or more, preferably 500 to 5,000 m 2 / g, more preferably 1,000 to 3,000 m 2 / g.
  • the allotrope of carbon include activated carbon, polyacene, carbon whisker, and graphite, and these powders or fibers can be used.
  • a preferred positive electrode active material is activated carbon, and specific examples include phenol-based, rayon-based, acrylic-based, pitch-based, and coconut shell-based activated carbon. These carbon allotropes can be used alone or in combination of two or more as the positive electrode active material. When carbon allotropes are used in combination, two or more types of carbon allotropes having different average particle diameters or particle size distributions may be used in combination.
  • a polyacene organic semiconductor (PAS) having a polyacene skeleton structure which is a heat-treated product of an aromatic condensation polymer and has an atomic ratio of hydrogen atom / carbon atom of 0.50 to 0.05, can be suitably used.
  • the electrode active material used for the negative electrode of the hybrid capacitor electrode is formed of a material that can reversibly carry lithium ions.
  • the electrode active material used in the negative electrode of the lithium ion secondary battery can be widely used.
  • Preferable examples include carbon materials such as graphite, non-graphitizable carbon, hard carbon and coke, and polyacene-based materials (PAS) described as the positive electrode active material. These carbon materials and PAS are obtained by carbonizing a phenol resin or the like, activated as necessary, and then pulverized.
  • the shape of the electrode active material used for the hybrid capacitor electrode is preferably a granulated particle.
  • the shape of the particles is spherical, a higher density electrode can be formed during electrode molding.
  • the volume average particle diameter of the electrode active material used for the electrode of the hybrid capacitor is usually 0.1 to 100 ⁇ m, preferably 1 to 50 ⁇ m, more preferably 5 to 20 ⁇ m for both the positive electrode and the negative electrode.
  • Electrode active materials can be used alone or in combination of two or more.
  • the conductive material is composed of an allotrope of particulate carbon that has conductivity and does not have pores that can form an electric double layer, and improves the conductivity of the electrode (positive electrode) for a hybrid capacitor.
  • Specific examples of the conductive material include conductive carbon black such as furnace black, acetylene black, and ketjen black (registered trademark of Akzo Nobel Chemicals Bethloten Fennot Shap); graphite such as natural graphite and artificial graphite; Can be mentioned.
  • conductive carbon black is preferable, and acetylene black and furnace black are more preferable.
  • the volume average particle diameter of the conductive material is preferably smaller than the volume average particle diameter of the electrode active material for the positive electrode, usually 0.001 to 10 ⁇ m, preferably 0.05 to 5 ⁇ m, more preferably 0.01 to 1 ⁇ m. Range. When the particle size of the conductive material is within this range, high conductivity can be obtained with a smaller amount of use.
  • the conductive materials can be used alone or in combination of two or more.
  • the amount of the conductive material is usually in the range of 0.1 to 50 parts by weight, preferably 0.5 to 15 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the electrode active material for the positive electrode. .
  • the capacity of the hybrid capacitor can be increased and the internal resistance can be decreased.
  • the binder is a compound that can bind an electrode active material, a conductive material, or the like.
  • polymer compounds such as fluorine-based polymers, diene-based polymers, acrylate-based polymers, polyimides, polyamides, and polyurethanes are preferable, and fluorine-based polymers, diene-based polymers, and acrylate-based polymers are preferable. It is done. Since the binder is usually a nonconductor, it becomes a resistance component.
  • fluorine-based polymers, diene-based polymers, and acrylate-based polymers are more preferable because there is little tendency to increase resistance. Among them, the diene polymer can reduce the amount of use because the electrode layer has a strong binding property.
  • a fluoropolymer is a polymer containing a monomer unit containing a fluorine atom.
  • the ratio of the monomer unit containing fluorine in the fluoropolymer is usually 50% by weight or more.
  • Specific examples of the fluorine-based polymer include fluorine resins such as polytetrafluoroethylene and polyvinylidene fluoride, and polytetrafluoroethylene is preferable.
  • the diene polymer is a homopolymer of a conjugated diene or a copolymer obtained by polymerizing a monomer mixture containing a conjugated diene, or a hydrogenated product thereof.
  • the proportion of the conjugated diene in the monomer mixture is usually 40% by weight or more, preferably 50% by weight or more, more preferably 60% by weight or more.
  • the diene polymer examples include conjugated diene homopolymers such as polybutadiene and polyisoprene; aromatic vinyl / conjugated diene copolymers such as carboxy-modified styrene / butadiene copolymer (SBR); Examples include vinyl cyanide / conjugated diene copolymers such as acrylonitrile / butadiene copolymer (NBR); hydrogenated SBR, hydrogenated NBR, and the like.
  • conjugated diene homopolymers such as polybutadiene and polyisoprene
  • aromatic vinyl / conjugated diene copolymers such as carboxy-modified styrene / butadiene copolymer (SBR)
  • SBR carboxy-modified styrene / butadiene copolymer
  • NBR acrylonitrile / butadiene copolymer
  • SBR acrylonitrile / butadiene copolymer
  • the acrylate polymer is a copolymer obtained by polymerizing a homopolymer of acrylic ester and / or methacrylic ester or a monomer mixture containing these.
  • the ratio of acrylic acid ester and / or methacrylic acid ester in the monomer mixture is usually 40% by weight or more, preferably 50% by weight or more, more preferably 60% by weight or more.
  • the acrylate polymer examples include 2-ethylhexyl acrylate / methacrylic acid / acrylonitrile / ethylene glycol dimethacrylate copolymer, 2-ethylhexyl acrylate / methacrylic acid / methacrylonitrile / diethylene glycol dimethacrylate copolymer, acrylic Crosslinking of 2-ethylhexyl acid / styrene / methacrylic acid / ethylene glycol dimethacrylate copolymer, butyl acrylate / acrylonitrile / diethylene glycol dimethacrylate copolymer, and butyl acrylate / acrylic acid / trimethylolpropane trimethacrylate copolymer
  • Type acrylate polymer ethylene / methyl acrylate copolymer, ethylene / methyl methacrylate copolymer, ethylene / ethyl acrylate copolymer, A copo
  • a radically polymerizable monomer used for the said graft polymer methyl methacrylate, acrylonitrile, methacrylic acid etc. are mentioned, for example.
  • a copolymer of ethylene and acrylic acid (or methacrylic acid) such as an ethylene / acrylic acid copolymer and an ethylene / methacrylic acid copolymer can be used as a binder.
  • the binder is not particularly limited depending on its shape, but has good binding properties and is particulate because it can suppress degradation of the produced hybrid capacitor due to decrease in capacitance and repeated charge / discharge. It is preferable.
  • the particulate binder include those in which particles of a dispersion-type binder such as latex are dispersed in water, and powders obtained by drying such a dispersion.
  • the number average particle diameter of the particulate binder is not particularly limited, but is usually 0.0001 to 100 ⁇ m, preferably 0.001 to 10 ⁇ m, more preferably 0.01 to 1 ⁇ m. When the number average particle diameter of the binder is within this range, an excellent binding force can be imparted to the electrode layer even when a small amount of the binder is used.
  • the number average particle diameter is a number average particle diameter calculated as an arithmetic average value obtained by measuring the diameter of 100 binder particles randomly selected in a transmission electron micrograph.
  • the shape of the particles can be either spherical or irregular.
  • the glass transition temperature (Tg) of the binder is preferably ⁇ 80 ° C. to 50 ° C., more preferably ⁇ 50 ° C. to 20 ° C.
  • Tg glass transition temperature
  • binders can be used alone or in combination of two or more.
  • the amount of the binder used is usually in the range of 0.1 to 50 parts by weight, preferably 0.5 to 20 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the electrode active material. .
  • the electrode material further contains a dispersing agent.
  • the dispersing material is used by being dissolved in a slurry solvent, and further has an action of uniformly dispersing the electrode active material, the conductive material and the like in the solvent.
  • cellulosic polymers such as carboxymethyl cellulose, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, and ammonium salts or alkali metal salts thereof; polyacrylic acid (or methacrylic acid) salts such as sodium polyacrylic acid (or methacrylic acid); polyvinyl Examples include alcohol, modified polyvinyl alcohol, polyethylene oxide; polyvinyl pyrrolidone, polycarboxylic acid, oxidized starch, phosphate starch, casein, various modified starches, chitin, and chitosan derivatives. These dispersing agents can be used alone or in combination of two or more. Among these, a cellulose polymer is preferable, and carboxymethyl cellulose or
  • the amount of the dispersing agent used is not particularly limited, but is usually 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, more preferably 0.8 parts per 100 parts by weight of the electrode active material. It is in the range of up to 2 parts by weight.
  • a dispersion material having a weight average molecular weight of 300,000 or more.
  • additives include, for example, surfactants.
  • surfactants include amphoteric surfactants such as anionic, cationic, nonionic, and nonionic anions. Among them, anionic or nonionic surfactants that are easily thermally decomposed are preferable.
  • Surfactants can be used alone or in combination of two or more.
  • the amount of the surfactant is not particularly limited, but is 0 to 50 parts by weight, preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the electrode active material. It is a range.
  • the electrode material used in the present invention contains the above-described electrode active material and binder as essential components, and contains a conductive material, a dispersing material, and other additives as necessary.
  • a suitably used electrode material is in the form of particles containing the above components in a composite (hereinafter sometimes referred to as “composite particles”). It is preferable that the composite particles usually contain at least an electrode active material and a binder, and the electrode active material is bound by a binder.
  • the production method of the composite particles is not particularly limited, and is a spray drying granulation method, a rolling bed granulation method, a compression granulation method, a stirring granulation method, an extrusion granulation method, a crushing granulation method, a fluidized bed granulation method. It can be produced by a known granulation method such as a granulation method, a fluidized bed multifunctional granulation method, or a melt granulation method. Among these, the spray-drying granulation method is preferable because composite particles in which the binder and the conductive auxiliary agent are unevenly distributed near the surface can be easily obtained. When composite particles obtained by the spray drying granulation method are used, the electrode of the present invention can be obtained with high productivity. In addition, the internal resistance of the electrode can be further reduced.
  • the composite particles suitably used in the present invention are preferably particles obtained by spray drying a slurry containing an electrode active material and a binder.
  • the composite particles are particles obtained by spray drying a slurry containing the electrode active material and the binder, the electrode of the present invention can be obtained with higher productivity, and the inside of the electrode Resistance can be further reduced.
  • the slurry can be obtained by dispersing or dissolving an optional component such as a conductive material, a dispersing agent, and other additives in a solvent in addition to the essential components of the electrode active material and the binder.
  • an optional component such as a conductive material, a dispersing agent, and other additives in a solvent in addition to the essential components of the electrode active material and the binder.
  • the solvent used in the slurry for obtaining composite particles water is usually used, but an organic solvent may be used.
  • the organic solvent include alkyl alcohols such as methyl alcohol, ethyl alcohol and propyl alcohol; alkyl ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran, dioxane and diglyme; diethylformamide, dimethylacetamide, N-methyl- Examples include amides such as 2-pyrrolidone and dimethylimidazolidinone; sulfur solvents such as dimethyl sulfoxide and sulfolane; and alcohols are preferable.
  • the drying rate can be increased during granulation by the spray drying method.
  • the dispersibility of the dispersion-type binder or the solubility of the soluble resin varies depending on the type of solvent, the viscosity and fluidity of the slurry are adjusted by selecting the amount or type of organic solvent, and spray drying production Efficiency can be improved.
  • the amount of the solvent used when preparing the slurry is such that the solid content concentration of the slurry is usually in the range of 1 to 50% by weight, preferably 5 to 50% by weight, more preferably 10 to 30% by weight. Amount.
  • the electrode active material and the binder there are no particular limitations on the essential components of the electrode active material and the binder, and the method or procedure for dispersing or dissolving the optional components in the solvent.
  • the electrode active material, the conductive material, the binder, and the other Method of adding and mixing optional components Method of adding and mixing a binder (for example, latex) dispersed in a solvent, and adding and mixing an electrode active material, a conductive material and the optional component; And a method in which a conductive material and other optional components dispersed in a solvent are added to a binder and mixed.
  • mixing means examples include mixing equipment such as a ball mill, a sand mill, a bead mill, a pigment disperser, a crusher, an ultrasonic disperser, a homogenizer, and a planetary mixer. Mixing is usually carried out in the range of room temperature to 80 ° C. for 10 minutes to several hours.
  • the spray drying method is a method in which slurry is sprayed and dried in hot air.
  • a typical example of the apparatus used for the spray drying method is an atomizer.
  • the rotating disk system is a system in which slurry is introduced almost at the center of a disk that rotates at high speed, and the slurry is released from the disk by the centrifugal force of the disk, and in that case, the slurry is dried in the form of a mist.
  • the rotational speed of the disk depends on the size of the disk, but is usually 5,000 to 30,000 rpm, preferably 15,000 to 30,000 rpm.
  • the pressurization method is a method in which the slurry is pressurized and sprayed from a nozzle to be dried.
  • the temperature of the slurry to be sprayed is usually room temperature, but it may be heated to room temperature or higher.
  • the hot air temperature at the time of spray drying is usually 80 to 250 ° C., preferably 100 to 200 ° C.
  • the method of blowing hot air is not particularly limited. Examples include a contact method, and a method in which sprayed droplets first flow in parallel with hot air and then drop by gravity to make countercurrent contact. Furthermore, heat treatment is performed to cure the surface of the composite particles.
  • the heat treatment temperature is usually 80 to 300 ° C.
  • the sphericity is preferably 80% or more, more preferably 90% or more.
  • the minor axis diameter Ls and the major axis diameter Ll are values measured from a transmission electron micrograph image.
  • the volume average particle diameter of the composite particles suitably used in the present invention is usually in the range of 10 to 100 ⁇ m, preferably 20 to 80 ⁇ m, more preferably 30 to 60 ⁇ m.
  • the volume average particle diameter can be measured using a laser diffraction particle size distribution measuring apparatus.
  • the composite particles suitably used in the present invention have a surface average porosity of preferably 15% or more, more preferably 20% or more, and further preferably 20% or more and 40% or less.
  • the “surface average porosity” is an apparent area of voids of 0.1 ⁇ m 2 or more on the surface of the composite particle for 5 particles or more (each with different fields of view) and 10 particles or more per composite particle. Is a value obtained as an average value of the ratio (%) of the apparent surface area of the void to the entire visual field area (hereinafter sometimes referred to as “void ratio”).
  • void ratio a value obtained as an average value of the ratio (%) of the apparent surface area of the void to the entire visual field area
  • the surface average porosity is obtained by taking an electron micrograph of the composite particles suitably used in the present invention, observing five or more different fields per arbitrarily selected particle, and an area of 0.1 ⁇ m 2 or more.
  • the apparent surface area of the continuous voids is measured, the same measurement is performed for 10 particles or more, and the average value of the obtained void ratios is calculated.
  • the apparent surface area of the void is an area corresponding to the surface area of the opening of the void observed on the electron micrograph, and is not an actual area taking into consideration the area in the pores of the void.
  • composite particles having a porosity of less than 15% may be included, but since the porosity includes a large number of particles having a porosity of 15% or more, the overall surface average porosity is As high as
  • the composite particles suitable for the present invention usually have a particle size displacement rate of 5 to 70%, preferably 20 to 50% when compressed to a maximum load of 9.8 mN at a load speed of 0.9 mN / sec using a micro compression tester. is there.
  • D1 is a value which changes according to a load amount with a particle size when applying a load.
  • the composite particles suitably used in the present invention preferably have a change amount of particle size displacement rate per unit second when compressed to a maximum load of 9.8 mN at a load speed of 0.9 mN / sec by a micro compression tester. It is 25% or less, more preferably 10% or less, and particularly preferably 7% or less.
  • the change amount of the particle size displacement rate per unit second is the change amount per unit second of the particle size change rate when the load is increased at a load speed of 0.9 mN / second.
  • the particle size displacement rate when compressed to a maximum load of 9.8 mN measured by a micro-compression tester is a numerical value necessary to show the shape maintenance force of the composite particles.
  • the particle size displacement rate is too small, the composite particles are hardly deformed even by pressurization, so that the contact area between the particles is small and the conductivity is not increased.
  • the particle size displacement rate is too large, the composite particles are crushed, the network formed by the conductive material and the electrode active material formed in the composite particles is broken, and the conductivity is lowered.
  • the change amount of the particle size displacement rate per unit second is an index for determining the presence or absence of crushing. When crushing occurs, the particle size decreases rapidly, so the amount of change in particle size displacement rate per unit second exceeds 25%. By crushing, the network formed by the conductive material and the electrode active material formed in the composite particles is broken, and the conductivity is lowered.
  • Composite particles having a particle size displacement rate of 5 to 70% when compressed to a maximum load of 9.8 mN have moderate softness, so that the contact area between the particles is large. And since it does not crush, the network of an electroconductive material and an electrode active material is maintained. These composite particles can be used alone or in combination of two or more.
  • the porous current collector used in the present invention is an electrode substrate having a current collecting function having front and back through-holes capable of batch doping of lithium ions on a negative electrode and / or a positive electrode necessary for a hybrid capacitor.
  • the material for example, metal, carbon, conductive polymer, and the like can be used, and metal is preferably used.
  • the current collector metal aluminum, platinum, nickel, tantalum, titanium, stainless steel, copper, other alloys and the like are usually used. Among these, it is preferable to use aluminum or an aluminum alloy in terms of conductivity and voltage resistance.
  • Examples of the shape of the front and back through holes include a rectangle, a rhombus, a turtle shell shape, a hexagon, a round shape, a star shape, and a cross shape.
  • Specific examples of porous collectors include expanded metal obtained by expanding a flat plate into a rhombus or turtle shell-shaped net, punching metal obtained by perforating a flat plate, and plain or twilled metal wires or metal bands. Or the metal net
  • the aperture ratio of the porous current collector used in the present invention is not particularly defined, it is preferably 10 to 90 area%, more preferably 40 to 60 area%, because the strength and molding speed can be increased.
  • the opening diameter is not particularly specified, but is usually 0.1 to 10 ⁇ m, more preferably 1 to 5 ⁇ m because the molding speed can be increased.
  • the opening diameter here is a diameter of a circumscribed circle of the opening. The diameter of the circumscribed circle is obtained by observing the surface of the current collector with a laser microscope or a tool microscope, fitting the circumscribed circle to the opening, and averaging the results.
  • the thickness of the porous current collector is appropriately selected according to the purpose of use, but is preferably 10 to 100 ⁇ m, more preferably 50 to 100 ⁇ m from the viewpoint of achieving both high strength and low resistance.
  • the current collector may be one obtained by applying a conductive adhesive on the surface thereof.
  • the conductive adhesive is obtained by dispersing a conductive auxiliary powder, a binder, and a dispersant added as necessary in water or an organic solvent.
  • the conductive assistant for the conductive adhesive include silver, nickel, gold, graphite, acetylene black, and ketjen black, and graphite and acetylene black are preferable.
  • the binder of the conductive adhesive any of those exemplified as the binder used in the electrode material of the present invention can be used.
  • the binder of the conductive adhesive is preferably an acrylate polymer, an ammonium salt or alkali metal salt of carboxymethyl cellulose, water glass, or polyamideimide resin.
  • a dispersing agent of a conductive adhesive a dispersing agent or a surfactant that may be used for the electrode layer of the electrode of the present invention can be used.
  • the electrode material is supplied to at least one surface of the porous current collector.
  • the feeder used in the step of supplying the electrode material is not particularly limited, but is preferably a quantitative feeder capable of supplying composite particles quantitatively.
  • the quantitative feeder used in the present invention preferably has a CV value of 2 or less.
  • Specific examples of the quantitative feeder include a gravity feeder such as a table feeder and a rotary feeder, and a mechanical force feeder such as a screw feeder and a belt feeder. Of these, the rotary feeder is preferred.
  • the porous current collector and the supplied electrode material are pressurized with a pair of rolls to form an electrode layer on the porous current collector.
  • the electrode material heated as necessary is formed into a sheet-like electrode layer by a pair of rolls.
  • the temperature of the electrode material supplied is preferably 40 to 160 ° C., more preferably 70 to 140 ° C. When an electrode material in this temperature range is used, there is no slip of the electrode material on the surface of the press roll, and the electrode material is continuously and uniformly supplied to the press roll. An electrochemical element electrode sheet with small variations can be obtained.
  • the molding temperature is usually 0 to 200 ° C., preferably higher than the melting point or glass transition temperature of the binder, and more preferably 20 ° C. higher than the melting point or glass transition temperature.
  • the forming speed is usually 10 m / min or more, and it is preferably 20 to 200 m / min, and more preferably 30 to 80 m / min, because the moldability is high and thinning is easy.
  • the forming speed here means the rotational speed of the roll.
  • the press linear pressure between the press rolls is not particularly defined, but is preferably 0.2 to 30 kN / cm, more preferably 0.5 to 10 kN / cm because the electrode strength can be increased.
  • the arrangement of the pair of rolls is not particularly limited, but is preferably arranged substantially horizontally or substantially vertically.
  • the porous current collector is continuously supplied between a pair of rolls, and an electrode material is supplied to at least one of the rolls, so that the gap between the porous current collector and the rolls is increased.
  • An electrode material is supplied to the electrode layer, and an electrode layer can be formed by pressurization.
  • the porous current collector is conveyed in the horizontal direction, an electrode material is supplied onto the current collector, and an electrode material layer is formed.
  • the current collector is supplied between a pair of rolls, and the electrode layer can be formed by pressurization.
  • the thickness of the electrode material layer supplied between the pair of rolls is a value represented by (roll gap between the pair of rolls) / (thickness of the porous current collector + thickness of the electrode material layer). From the viewpoint of excellent moldability, it is preferably 0.01 to 1, more preferably 0.05 to 0.75, and particularly preferably 0.1 to 0.5.
  • the post-pressing method is generally a press process using a roll.
  • the roll press process two cylindrical rolls are arranged in parallel at a narrow interval in the vertical direction, and each is rotated in the opposite direction.
  • the temperature of the roll may be adjusted by heating or cooling.
  • the electrode for a hybrid capacitor obtained by the production method of the present invention is suitably used for a hybrid capacitor using an aprotic organic solvent forming an aprotic organic solvent electrolyte solution as an electrolyte solvent.
  • the aprotic organic solvent include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ⁇ -butyrolactone, acetonitrile, dimethoxyethane, tetrahydrofuran, dioxolane, methylene chloride, sulfolane and the like.
  • a mixed solution in which two or more of these aprotic organic solvents are mixed can also be used.
  • any electrolyte can be used as long as it is an electrolyte capable of generating lithium ions as the electrolyte dissolved in the electrolyte solution solvent used alone or in combination.
  • Examples of such an electrolyte include LiClO4, LiAsF6, LiBF4, LiPF6, LiN (C2F5SO2) 2, LiN (CF3SO2) 2, and the like.
  • the electrolyte and the electrolyte solvent are mixed in a sufficiently dehydrated state to obtain an electrolyte solution.
  • the electrolyte concentration in the electrolyte is at least 0.1 mol in order to reduce the internal resistance of the electrolyte. / Liter or more is preferable, and the range of 0.5 to 1.5 mol / liter is more preferable.
  • the hybrid capacitor is a winding type in which a strip-like positive electrode and a negative electrode are wound through a separator, or a laminated type in which a plate-like positive electrode and a negative electrode are laminated through a separator.
  • a separator to be used a microporous film made of polypropylene or polyethylene having a thickness of 25 ⁇ m to 100 ⁇ m and a porosity of about 30% to 80% can be generally used. If the thickness is less than 25 ⁇ m, it may cause micro-shorts, or the amount of electrolyte solution retained will decrease and the cell characteristics will deteriorate. On the other hand, if the thickness exceeds 100 ⁇ m, the internal resistance of the cell increases.
  • the porosity of the separator can be obtained by converting the ratio of ⁇ 1- (separator weight / separator material density) / (separator apparent volume) ⁇ into a percentage.
  • a negative electrode capable of inserting and extracting lithium ions is brought into contact with lithium metal, and lithium ions are inserted and stored (hereinafter also referred to as doping) by a chemical method or an electrochemical method in advance to lower the negative electrode potential.
  • doping lithium ions are inserted and stored (hereinafter also referred to as doping) by a chemical method or an electrochemical method in advance to lower the negative electrode potential.
  • the withstand voltage can be increased and the energy density can be greatly increased.
  • the hybrid capacitor including the electrode for a hybrid capacitor obtained by the manufacturing method of the present invention uses a porous current collector, lithium ions can move through the through-hole, and lithium metal is placed at the end of the cell. By simply disposing, all the negative electrodes in the cell can be smoothly and uniformly doped with lithium ions.
  • Lithium ion doping may be one or both of the negative electrode and the positive electrode.
  • the lithium ion when activated carbon is used for the positive electrode, the lithium ion is irreversibly consumed when the amount of lithium ion doping increases and the positive electrode potential decreases. In other words, a problem such as a decrease in cell capacity may occur. For this reason, it is preferable that the lithium ions doped in the negative electrode and the positive electrode do not cause these problems in consideration of the respective electrode active materials. Since controlling the doping amount of the positive electrode and the doping amount of the negative electrode is complicated in the process, the doping of lithium ions is preferably performed on the negative electrode.
  • the average surface porosity of the composite particles produced in the following examples and comparative examples is determined by the following method. First, an electron micrograph of the composite particles was measured at a magnification of 2000 times, and arbitrary particles were read into image analysis software (analySIS: Soft Imaging System) as black and white 256-gradation image data within a field of view of 20 ⁇ m. The contrast is optimized so that the brightest part of the image is 255 and the darkest part is zero. Next, the threshold value is set to 77, binarization processing is performed, and the ratio of voids having an area of 0.1 ⁇ m 2 or more on the composite particle surface is obtained from the obtained binarized image. For the same particle, the same measurement is performed 5 times in any different field of view, and the same measurement is performed for 10 particles, and the average is the surface average porosity of the composite particles.
  • the electrode layer thickness is measured using an eddy current displacement sensor (sensor head unit EX-110V, amplifier unit unit EX-V02: manufactured by Keyence Corporation) after forming electrode layers on both sides of the current collector.
  • the thickness of each electrode layer is measured at intervals of 10 cm in the longitudinal direction and at intervals of 2 cm in the width direction, and the average value thereof is taken as the thickness of the electrode layer.
  • a hybrid capacitor of a laminated laminate cell is manufactured using the hybrid capacitor electrode manufactured in the examples and comparative examples, and the capacity and internal resistance are measured by performing charge / discharge operation after being allowed to stand for 24 hours.
  • charging starts with a constant current of 2 A, and when the voltage reaches 3.6 V, the voltage is maintained for 1 hour to be constant voltage charging.
  • Discharging is performed immediately after the end of charging until it reaches 1.9 V at a constant current of 0.9 A.
  • the capacity is calculated as the capacity per weight of the electrode active material from the energy amount at the time of discharge.
  • the internal resistance is calculated from the voltage drop immediately after discharge.
  • Example 1 (Preparation of composite particles used for positive electrode layer formation) 100 parts of electrode active material (activated carbon with a specific surface area of 2,000 m2 / g and a weight average particle diameter of 5 ⁇ m), 5 parts of conductive material (acetylene black “Denka black powder”: manufactured by Denki Kagaku Kogyo Co., Ltd.), dispersive binding 7.5 parts of an agent (a cross-linked acrylate polymer having a number average particle diameter of 0.15 ⁇ m and a glass transition temperature of ⁇ 40 ° C., 40% aqueous dispersion “AD211” manufactured by Nippon Zeon Co., Ltd.) Dissolved resin (1.5% aqueous solution of carboxymethyl cellulose “DN-800H”, weight average molecular weight of carboxymethyl cellulose less than 300,000: manufactured by Daicel Chemical Industries, Ltd.) 1.4 parts in solids equivalent, and ion-exchanged water Is stirred and mixed with “TK homomixer” (manufacture
  • this slurry is spray-dried with hot air at 150 ° C. using a spray dryer to obtain an electrode material as spherical composite particles having a volume average particle diameter of 50 ⁇ m and a surface average porosity of 13%.
  • the volume average particle size of the composite particles is measured using a particle size distribution measuring device (SALD-3100: manufactured by Shimadzu Corporation).
  • SALD-3100 manufactured by Shimadzu Corporation.
  • a 0.5 mm thick phenolic resin molded plate is placed in a siliconite electric furnace and heated to a temperature of 50 ° C./hour up to 500 ° C. and further to 660 ° C. at a rate of 10 ° C./hour in a nitrogen atmosphere. Synthesize polyacene.
  • the polyacene plate thus obtained is pulverized by a disk mill and sieved to obtain a PAS powder having an average particle diameter of 5 ⁇ m.
  • the polyacene powder has an H / C ratio of 0.21.
  • dispersion-type binder 50% aqueous dispersion “AD211” of a cross-linked acrylate polymer having a number average particle size of 0.15 ⁇ m and a glass transition temperature of ⁇ 40 ° C .: manufactured by Nippon Zeon Co., Ltd.
  • dissolved resin (1.5% aqueous solution of carboxymethyl cellulose “DN-800H”, weight average molecular weight of carboxymethyl cellulose less than 300,000: manufactured by Daicel Chemical Industries, Ltd.
  • 1.4 parts and ion-exchanged water are added, and the mixture is stirred and mixed with “TK homomixer” (manufactured by Tokushu Kika Kogyo Co., Ltd.) to obtain a slurry with a solid content concentration of 25%.
  • TK homomixer manufactured by Tokushu Kika Kogyo Co., Ltd.
  • the slurry is spray-dried with hot air at 150 ° C. using a spray dryer to obtain an electrode material as spherical composite particles having a volume average particle diameter of 50 ⁇ m and a surface average porosity of 13%.
  • the volume average particle size of the composite particles is measured using a particle size distribution measuring device (SALD-3100: manufactured by Shimadzu Corporation).
  • SALD-3100 manufactured by Shimadzu Corporation.
  • expanded metal used as a current collector 1 is supplied between forming rolls (press rolls) 2.2, and composite particles 4 and 4 are respectively formed using powder supply devices 3 and 3.
  • Rolls 2 and 2 (roll temperature: 120 ° C., press linear pressure: 4 kN / cm) are subjected to pressure molding at a molding speed of 5 m / min to obtain an electrode sheet for a positive electrode.
  • the electrode sheet for negative electrodes is obtained like the above except using the composite particles for negative electrodes as composite particles.
  • the roll gap between the pair of rolls is such that the values of (roll gap between the pair of rolls) / (thickness of the porous current collector + thickness of the electrode material layer) are all 0.5. And adjust the thickness of the electrode material layer.
  • the above-mentioned electrode sheet is cut out so that the collector sheet portion on which the electrode layer is not formed is 2 cm long ⁇ 2 cm wide and the portion on which the electrode layer is formed is 5 cm long ⁇ 5 cm wide.
  • a tab material made of aluminum having a length of 7 cm, a width of 1 cm, and a thickness of 0.01 cm is ultrasonically welded to the uncoated portion to produce a measurement electrode.
  • 10 sets of positive electrodes and 11 sets of negative electrodes are prepared and dried at 160 ° C. for 40 minutes.
  • the terminal welds of the positive electrode current collector and the negative electrode current collector are arranged on opposite sides, and the opposing surfaces of the positive electrode and the negative electrode are 20 layers.
  • lamination is performed so that the outermost electrode of the laminated electrodes becomes a negative electrode.
  • the uppermost part and the lowermost part are provided with separators, and four sides are taped, and the terminal welded part (10 sheets) of the positive electrode current collector and the terminal welded part (11 sheets) of the negative electrode current collector are ultrasonically welded.
  • a lithium metal foil (thickness 82 ⁇ m, length 5 cm ⁇ width 5 cm) bonded to an 80 ⁇ m-thick stainless steel mesh is used, and the lithium electrode is laminated so as to completely face the outermost negative electrode One sheet is placed at the top and one at the bottom.
  • the terminal welding part (two sheets) of the lithium electrode current collector is resistance-welded to the negative electrode terminal welding part.
  • Laminate with the lithium foil placed at the top and bottom is placed inside the deep-drawn lower exterior film, covered with the exterior laminate film and fused on the three sides, and then ethylene carbonate, diethyl carbonate and propylene carbonate are used as the electrolyte.
  • a solution obtained by dissolving LiPF6 at a concentration of 1 mol / liter is vacuum impregnated in a mixed solvent with a weight ratio of 3: 4: 1, and the remaining side is then fused to produce a film type capacitor. Each characteristic is measured about the film type capacitor obtained. The results are shown in Table 1.
  • Example 2 An electrode sheet and a film type capacitor are produced in the same manner as in Example 1 except that the molding speed is 15 m / min. The results are shown in Table 1.
  • Example 3 An electrode sheet and a film type capacitor are produced in the same manner as in Example 1 except that a punching metal having a thickness of 30 ⁇ m, an opening area of 37 area%, and an opening diameter of 0.1 ⁇ m is used as the porous collector. The results are shown in Table 1.
  • Example 4 An electrode sheet and a film type capacitor are produced in the same manner as in Example 3 except that the molding speed is 15 m / min. The results are shown in Table 1.
  • Example 5 An electrode sheet and a film type capacitor are produced in the same manner as in Example 3 except that the molding speed is 40 m / min. The results are shown in Table 1.
  • Example 6 An electrode sheet and a film type capacitor are obtained in the same manner as in Example 5 except that a punching metal having a thickness of 30 ⁇ m, an opening area of 60 area%, and an opening diameter of 0.1 ⁇ m is used as the porous current collector. The results are shown in Table 1.
  • Example 7 An electrode sheet and a film type capacitor are obtained in the same manner as in Example 5 except that a punching metal having a thickness of 30 ⁇ m, an opening area of 60 area%, and an opening diameter of 3 ⁇ m is used as the porous current collector. The results are shown in Table 1.
  • Example 8 In the preparation of composite particles used for forming the positive electrode layer, the soluble resin was replaced with another soluble resin (1% aqueous solution of carboxymethyl cellulose “BSH-12”: weight average molecular weight of carboxymethyl cellulose 330,000 to 380,000, first An electrode sheet and a film type capacitor are obtained in the same manner as in Example 7 except that the material is changed to Kogyo Kagaku Co. The results are shown in Table 1.
  • the volume average particle diameter of the composite particles used for forming the positive electrode layer is 50 ⁇ m, and the surface average porosity is 22%.
  • Comparative Example 1 Preparation of paint used for positive electrode layer formation
  • coconut shell By using coconut shell as a raw material, placing it in an electric furnace, raising the temperature to 950 ° C. at a rate of 50 ° C./hour under a nitrogen stream, and then activating it with a mixed gas of nitrogen / steam 1: 1 for 2 hours, An activated carbon having a surface area of 1,860 m 2 / g is produced.
  • the activated carbon is pulverized by a ball mill pulverizer to obtain activated carbon powder having an average particle size of 5 ⁇ m.
  • a positive electrode paint is obtained by mixing 92 parts of the above activated carbon powder, 4 parts of acetylene black powder, 4 parts of styrene-butadiene rubber (SBR) and 1 part of carboxymethylcellulose, and adding ion-exchanged water to the composition, the solid content is 35%.
  • a positive electrode paint is obtained by mixing.
  • the gap between the die and the roll bar is 300 ⁇ m
  • the gap between the die lip is 150 ⁇ m
  • the positive electrode paint is discharged to perform double-side coating to obtain a positive electrode.
  • the winding tension is 5 N
  • the expanded metal feed speed (coating speed) is 0.5 m / min.
  • the temperature in the drying furnace is set to 70 ° C.
  • a 0.5 mm thick phenolic resin molded plate is placed in a siliconite electric furnace, heated to 500 ° C. at a rate of 50 ° C./hour, and further at a rate of 10 ° C./hour to 650 ° C. in a nitrogen atmosphere, followed by heat treatment.
  • a polyacene (PAS) plate is synthesized.
  • the PAS plate thus obtained is pulverized with a ball mill to obtain a PAS powder having a volume average particle diameter of 7 ⁇ m.
  • a negative electrode paint is obtained by sufficiently mixing at a composition of 50%.
  • a copper expanded metal manufactured by Nippon Metal Industry Co., Ltd. having a thickness of 32 ⁇ m (opening ratio 50%, opening diameter 1 mm) as a porous current collector is fixed to a raw fabric hoop installation roll, and the expanded metal is passed through a guide roll. Then, it passes between the die and the roll bar, and is fixed to the winding part through a 2 m drying furnace.
  • the winding tension is 5 N
  • the expanded metal feed rate is 0.5 m / min.
  • the temperature in the drying furnace is set to 70 ° C.
  • the negative electrode is obtained by coating on both sides in the same manner as the positive electrode except that the current collector and the negative electrode paint obtained above are used.
  • a film type capacitor is produced in the same manner as in Example 1 except that the positive electrode and the negative electrode thus obtained are used. The results are shown in Table 1.
  • Comparative Example 2 An electrode sheet and a film type capacitor are obtained in the same manner as in Comparative Example 1 except that the expanded metal feed rate (coating rate) is 5 m / min. The results are shown in Table 1. On the paint coated surface on the expanded metal, there is a portion where no paint is applied (uncoated portion). Therefore, variation (5 to 60 ⁇ m) is observed in the thickness of the electrode layer.
  • Comparative Example 3 If an electrode sheet is produced in the same manner as in Comparative Example 1 except that the expanded metal feed rate (coating speed) is 15 m / min, the expanded metal that is the current collector is broken and the electrode sheet cannot be produced. . The results are shown in Table 1.
  • Comparative Example 4 An electrode sheet and a film type capacitor are obtained in the same manner as in Comparative Example 1 except that a punching metal having a thickness of 30 ⁇ m, an opening area of 60 area%, and an opening diameter of 3 ⁇ m is used as the porous collector. The results are shown in Table 1.
  • Comparative Example 5 An electrode sheet and a film type capacitor are obtained in the same manner as in Comparative Example 4 except that the feed rate (coating speed) of the punching metal is 5 m / min. The results are shown in Table 1. On the coated surface on the expanded metal, a portion where no paint is applied (uncoated portion) is seen. Therefore, variation (5 to 60 ⁇ m) is observed in the thickness of the electrode layer.
  • Comparative Example 6 When the electrode sheet is manufactured in the same manner as in Comparative Example 4 except that the feed rate (coating speed) of the punching metal is 15 m / min, the expanded metal as the current collector is broken and the electrode sheet cannot be created. . The results are shown in Table 1.
  • the present invention relates to the subject matter contained in Japanese Patent Application No. 2008-79276 filed on Mar. 25, 2008, the entire disclosure of which is expressly incorporated herein by reference.

Abstract

An electrode for a hybrid capacitor can be produced through the steps of: supplying an electrode material on at least one surface of a porous current collector; and pressurizing the porous current collector and the electrode material together to form an electrode layer on the porous current collector. In the electrode produced by this process, a porous current collector is used and, therefore, doping of a lithium ion into a negative electrode and/or a positive electrode can be achieved by one operation.

Description

ハイブリッドキャパシタ用電極の製造方法Method for manufacturing electrode for hybrid capacitor
　本発明は、リチウムイオン及び／又はアニオンを可逆的に担持可能な物質からなる正極とリチウムイオンを可逆的に担持可能な物質からなる負極で構成されたハイブリッドキャパシタに好適に用いられるハイブリッドキャパシタ用電極の製造方法に関する。 The present invention relates to an electrode for a hybrid capacitor that is suitably used for a hybrid capacitor composed of a positive electrode made of a material capable of reversibly supporting lithium ions and / or anions and a negative electrode made of a material capable of reversibly supporting lithium ions. It relates to the manufacturing method.
　小型で軽量、且つエネルギー密度が高く、更に繰り返し充放電が可能なリチウムイオン二次電池や電気二重層キャパシタなどの電気化学素子は、その特性を活かして急速に需要を拡大している。リチウムイオン二次電池は、エネルギー密度が比較的大きいことから携帯電話やノート型パーソナルコンピュータなどの分野で利用され、電気二重層キャパシタはパソコン等のメモリバックアップ小型電源として利用されている。更に、最近は、電気二重層キャパシタは急速充放電特性に優れることから、繰り返しの充放電が必要なショベル、クレーンなどの建設機械での使用が本格化してきている。一方で、電気二重層キャパシタのエネルギー密度は３～４Ｗｈ／リットル程度で、リチウムイオン二次電池に比べて二桁程度小さい。そのため、高いエネルギー密度と充放電速度の両立を目指し、正極、負極の２つの電極のうち、一方にファラデー反応電極、他方に非ファラデー反応電極を使用するハイブリッドキャパシタも開発が進められてきている。ハイブリッドキャパシタは安全性と高容量と急速充放電を兼ね備えた電気化学素子として大いに期待されている。 Electrochemical elements such as lithium ion secondary batteries and electric double layer capacitors that are small and light, have high energy density, and can be repeatedly charged and discharged are rapidly expanding their demands by taking advantage of their characteristics. Lithium ion secondary batteries have a relatively high energy density and are therefore used in fields such as mobile phones and notebook personal computers. Electric double layer capacitors are used as memory backup compact power sources for personal computers and the like. Furthermore, recently, electric double layer capacitors are excellent in rapid charge / discharge characteristics, so that they have been used in construction machines such as excavators and cranes that require repeated charge / discharge. On the other hand, the energy density of the electric double layer capacitor is about 3 to 4 Wh / liter, which is about two orders of magnitude smaller than that of the lithium ion secondary battery. Therefore, a hybrid capacitor using a Faraday reaction electrode for one of the two electrodes, the positive electrode and the negative electrode, and a non-Faraday reaction electrode for the other has been developed with the aim of achieving both a high energy density and a charge / discharge rate. Hybrid capacitors are highly expected as electrochemical devices that combine safety, high capacity, and rapid charge / discharge.
　リチウムイオン二次電池はエネルギー密度は大きいが、出力密度、サイクル特性、安全性には課題を残している。出力密度向上のためには電極の厚みを薄くしたり、電極の多孔度を上げることでイオン拡散を速めて低抵抗化を図っている。しかしながら、電極を薄くする方法では、セパレーターや集電体といった容量に寄与しない部材の使用比率が増加し、セルに占める電極の比率が減少し、エネルギー密度が低下するといった問題点を有している。また、電極の多孔化もセルへの活物質の充填量が減少するため、エネルギー密度が低下するといった問題点がある。 Lithium ion secondary batteries have a high energy density, but have problems in output density, cycle characteristics, and safety. In order to improve the power density, the ion diffusion is accelerated by reducing the thickness of the electrode or increasing the porosity of the electrode to reduce the resistance. However, in the method of thinning the electrodes, there is a problem that the usage ratio of members that do not contribute to capacity such as separators and current collectors increases, the ratio of the electrodes occupying the cells decreases, and the energy density decreases. . In addition, since the electrode is made porous, the amount of the active material filled in the cell is reduced, so that the energy density is lowered.
　また、活物質の粒子径を小さくすることで出力密度の向上が図られている。しかしながら、リチウムイオン二次電池の電極は活物質を含む電極スラリーを集電体上に塗布して製造されるが、活物質の粒子径を小さくするとスラリーの流動性が悪化したり、スラリー濃度が低下し、塗布速度が上げられないといった問題点がある。また、サイクル特性に関しては、ファラデー反応を伴う電池の宿命として、充放電を繰り返す用途では、充放電深度の浅いところで使用する方法が一般的に使用され、余分な電池の搭載が必要になる。 Also, the power density is improved by reducing the particle size of the active material. However, an electrode of a lithium ion secondary battery is manufactured by applying an electrode slurry containing an active material on a current collector. However, when the particle size of the active material is reduced, the fluidity of the slurry is deteriorated or the slurry concentration is reduced. There is a problem that the coating speed cannot be increased. In addition, regarding the cycle characteristics, as a battery fate with a Faraday reaction, in applications where charging and discharging are repeated, a method of using at a shallow charge / discharge depth is generally used, and an extra battery needs to be mounted.
　一方、安全性に関しては、正極にリチウム含有複合酸化物が一般的に用いられるが、充電状態での結晶構造の不安定さなどから、本質的な課題が残されている。 On the other hand, with regard to safety, lithium-containing composite oxides are generally used for the positive electrode, but the essential problems remain due to the instability of the crystal structure in the charged state.
　電気二重層キャパシタは出力密度は大きいがエネルギー密度が小さく、その材料として、高容量化を目指した新しい炭素材料の開発が進められてきた。例えば、カリウムを用いたアルカリ賦活炭の提案（日本国特開２００４－４７６１３号公報）や電界賦活処理が提案されている（日本国特開２００２－２５８６７号公報）。しかしながら、これらの提案はサイクル特性の低下から実用化には問題が残されている。また、電気二重層キャパシタのエネルギー密度を高めるため突起を有する集電体を用いたり(日本国特開平１０－２８４３４９号公報)、金属繊維集電体を用いて、活物質を集電体に充填する提案が見られる（日本国特開平９－２３２１９０号公報、日本国特開平６－１９６１７０号公報）。これらの提案では電極厚みを厚くしても電極内に存在する集電体によって集電性が高められるため、出力密度の高い電極を得ることが可能で、セルに占める活物質の比率を増加できることからエネルギー密度を上げることができるとしている。しかしながら、これらの提案で期待できるエネルギー密度の向上は数十％程度であり、二次電池と比べると未だ不十分なものであった。更に、これらの提案は分極性電極内に金属からなる集電体を配置することで電気抵抗を下げる効果はあるが、イオン拡散抵抗を下げる効果を発現することはできない。したがって、一定の効果はあるが、高速の充放電を伴う使われ方では抵抗低下に限界があった。 Electric double layer capacitors have a high output density but a low energy density, and new carbon materials aimed at higher capacity have been developed as materials. For example, a proposal of alkali activated charcoal using potassium (Japanese Unexamined Patent Publication No. 2004-47613) and an electric field activation treatment have been proposed (Japanese Unexamined Patent Publication No. 2002-25867). However, these proposals still have problems in practical use due to the deterioration of cycle characteristics. Also, a current collector having protrusions is used to increase the energy density of the electric double layer capacitor (Japanese Patent Laid-Open No. 10-284349), or a metal fiber current collector is used to fill the current collector with the active material. (See Japanese Patent Laid-Open No. 9-232190, Japanese Patent Laid-Open No. 6-196170). In these proposals, even if the electrode thickness is increased, the current collection is enhanced by the current collector present in the electrode, so that it is possible to obtain an electrode with a high output density and to increase the proportion of the active material in the cell. It is said that the energy density can be increased. However, the improvement in energy density that can be expected with these proposals is about several tens of percent, which is still insufficient as compared with the secondary battery. Furthermore, these proposals have the effect of lowering the electrical resistance by disposing a current collector made of metal in the polarizable electrode, but cannot produce the effect of lowering the ion diffusion resistance. Therefore, although there is a certain effect, there is a limit to the decrease in resistance when used with high-speed charging / discharging.
　一方で、高いエネルギー密度と充放電速度の両立を目指し、正極、負極の２つの電極のうち、一方にファラデー反応電極を、他方に非ファラデー反応電極を使用するハイブリッドキャパシタが注目されている。ハイブリッドキャパシタではリチウムイオンを吸蔵、離脱しうる炭素材料を使用し、予めリチウムイオンをドープする必要がある。リチウムイオンを吸蔵、離脱しうる炭素材料に予めリチウムイオンを吸蔵させる方法として、予め粉末状のリチウムをリチウムイオンを吸蔵、離脱しうる炭素材料の粉末に混ぜておいたり、リチウムイオンを吸蔵、脱離しうる炭素材料と結合剤の成形体に箔状のリチウムを電気的に接触させた状態で電解液中に浸漬することによりリチウムをイオン化させ、リチウムイオンを該炭素材料中に取り込ませる化学的方法；リチウム塩を電解質とする非水（有機）溶媒の電解液中の、一方にリチウムイオンを吸蔵、離脱しうる炭素材料と結合剤により形成された電極を置き、他方にリチウム金属の電極を置いて電流を印加し、炭素材料中にリチウムイオンを吸蔵させる電気化学的方法；などが提案されており、貫通孔を有する集電体を用いてセルを組み立てて、セル内でドープを行う方法で実現性が高まってきた（日本国特許第４０１５９９３号）。すなわち、リチウムイオン及び／又はアニオンを可逆的に担持可能な物質からなる正極と、リチウムイオンを可逆的に担持可能な物質からなる負極とで構成されたハイブリッドキャパシタであって、負極及び／又は正極とリチウム金属箔との電気化学的接触によってセル内でリチウムイオンを負極及び／又は正極にドーピングする方法が提案されている。その際、貫通孔を有する集電体を使用することで、積層された電極シートの垂直方向からのリチウムイオンの透過が可能になるため、効率よく、均一にセル内の電極にリチウムイオンのドープを行うことができるとしている。 On the other hand, a hybrid capacitor using a Faraday reaction electrode for one of the positive electrode and the negative electrode and a non-Faraday reaction electrode for the other has been attracting attention in order to achieve both high energy density and charge / discharge speed. In the hybrid capacitor, it is necessary to use a carbon material capable of inserting and extracting lithium ions and to dope lithium ions in advance. As a method of preliminarily occluding lithium ions in a carbon material that can occlude and desorb lithium ions, powdered lithium is mixed in advance with a carbon material powder that can occlude and desorb lithium ions, or lithium ions can be occluded and desorbed. A chemical method of ionizing lithium by immersing it in an electrolytic solution in a state in which foil-like lithium is in electrical contact with a molded body of a carbon material and a binder that can be released, and incorporating lithium ions into the carbon material. An electrode formed of a carbon material capable of inserting and extracting lithium ions and a binder is placed on one side of an electrolyte solution of a non-aqueous (organic) solvent containing lithium salt as an electrolyte, and a lithium metal electrode is placed on the other side An electrochemical method in which an electric current is applied and lithium ions are occluded in a carbon material has been proposed, and a cell is formed using a current collector having a through hole. Upright seen, there has been an increased possibility in a way to do the dope in the cell (Japanese Patent No. 4015993). That is, a hybrid capacitor including a positive electrode made of a material capable of reversibly supporting lithium ions and / or anions and a negative electrode made of a material capable of reversibly supporting lithium ions, the negative electrode and / or the positive electrode A method has been proposed in which lithium ions are doped into a negative electrode and / or a positive electrode in a cell by electrochemical contact between the lithium metal foil and the lithium metal foil. At that time, by using a current collector having a through-hole, it is possible to transmit lithium ions from the vertical direction of the laminated electrode sheet, so that the lithium ion can be efficiently and uniformly doped into the electrodes in the cell. You can do that.
　しかしながら、上記提案では電極層構造に対する工夫は見られず、電極層の厚みを厚くするとドーピング時間が長くなったり、ドーピングが不均一になるなど課題が残されていた。更に、貫通孔を有する集電体への電極の形成は難しく、生産性が悪いといった問題点を有している。すなわち、電極活物質を含むスラリー状物を塗布又は浸漬によりエキスパンドメタル、パンチドメタルなどの有孔性集電体に担持せしめる際、貫通孔の径が大きいためにダイコーターなどを必要とし、ある場合には、下塗りなどを必要とした。更に、通常、垂直方向に引き上げながら塗布するために強度上の問題から生産性が低かった。（日本国特開２００５－２０３１１５号公報）。 However, in the above proposal, no contrivance for the electrode layer structure was found, and problems such as a longer doping time and non-uniform doping were left when the thickness of the electrode layer was increased. Furthermore, it is difficult to form an electrode on a current collector having a through-hole, resulting in poor productivity. That is, when a slurry-like material containing an electrode active material is carried on a porous current collector such as an expanded metal or a punched metal by coating or dipping, a die coater or the like is required because the diameter of the through hole is large. In some cases, an undercoat was required. Further, since the coating is usually performed while pulling up in the vertical direction, the productivity is low due to a problem in strength. (Japanese Unexamined Patent Publication No. 2005-203115).
　本発明の目的は、低抵抗のハイブリッドキャパシタを与えるハイブリッドキャパシタ用電極を大量に効率よく製造する方法を提供することにある。 An object of the present invention is to provide a method for efficiently producing a large number of electrodes for a hybrid capacitor that provides a low-resistance hybrid capacitor.
　本発明者は、上記課題に鑑み鋭意検討した結果、負極及び／又は正極へのリチウムイオンの一括ドープが可能な多孔化集電体を用い、ロール成形することにより、低抵抗のハイブリッドキャパシタを与えるハイブリッドキャパシタ用電極が得られることを見出した。さらに、加圧装置として一対のロールを備える加圧装置を用い、電極層を形成する工程における成形速度を１０ｍ／分以上とし、電極材料として電極活物質が結着剤によって結着されてなる複合粒子を用い、プレス用ロールのロール間隙、多孔化集電体の開口面積および開口径を特定の範囲にすることによりさらなる低抵抗化が可能であることを見出した。本発明者は、これらの知見に基づいて本発明を完成するに至ったものである。 As a result of intensive studies in view of the above problems, the present inventor gives a low-resistance hybrid capacitor by roll forming using a porous current collector capable of collectively doping lithium ions into the negative electrode and / or the positive electrode. It has been found that an electrode for a hybrid capacitor can be obtained. Further, a pressure device comprising a pair of rolls as a pressure device, a molding speed of 10 m / min or more in the step of forming the electrode layer, and a composite comprising an electrode active material bound by a binder as an electrode material It has been found that the resistance can be further reduced by using particles and setting the roll gap of the press roll, the opening area and the opening diameter of the porous collector to a specific range. The present inventor has completed the present invention based on these findings.
　本発明によれば、多孔化集電体上の少なくとも一表面に電極材料を供給する工程、および前記多孔化集電体と前記電極材料とを加圧して多孔化集電体上に電極層を形成する工程を含んでなるハイブリッドキャパシタ用電極の製造方法が提供される。また、本発明によれば前記製造方法により得られたハイブリッドキャパシタ用電極を備えるハイブリッドキャパシタが提供される。 According to the present invention, the electrode material is supplied to at least one surface of the porous current collector, and the electrode layer is formed on the porous current collector by pressurizing the porous current collector and the electrode material. There is provided a method for manufacturing an electrode for a hybrid capacitor comprising a forming step. Moreover, according to this invention, a hybrid capacitor provided with the electrode for hybrid capacitors obtained by the said manufacturing method is provided.
　本発明において、前記加圧は、一対のロールを備える加圧装置で行うようにできる。この場合において、（前記一対のロールのロール間隙）／（前記多孔化集電体の厚さ＋前記電極材料層の厚さ）を０．０１～１に設定すると良い。また、前記電極層を形成する工程における成形速度としては、１０ｍ／分以上とすることができる。更に、前記電極材料としては、電極活物質および結着剤を含有し、且つ該電極活物質が該結着剤によって結着されてなる複合粒子を用いることができる。また、前記多孔化集電体の開口面積は１０～９０面積％、前記多孔化集電体の開口径は０．１～１０μｍの範囲でそれぞれ設定することができる。 In the present invention, the pressurization can be performed by a pressurization apparatus including a pair of rolls. In this case, it is preferable to set (roll gap between the pair of rolls) / (thickness of the porous current collector + thickness of the electrode material layer) to 0.01 to 1. Moreover, as a shaping | molding speed | rate in the process of forming the said electrode layer, it can be 10 m / min or more. Furthermore, as the electrode material, composite particles containing an electrode active material and a binder, and the electrode active material bound by the binder can be used. The opening area of the porous current collector can be set in the range of 10 to 90 area%, and the opening diameter of the porous current collector can be set in the range of 0.1 to 10 μm.
　本発明によれば、低抵抗のハイブリッドキャパシタを与えるハイブリッドキャパシタ用電極を大量に効率よく製造できる。 According to the present invention, it is possible to efficiently manufacture a large number of hybrid capacitor electrodes that provide a low-resistance hybrid capacitor.
本発明の実施例で用いた電極用シートの製造装置を示す図である。It is a figure which shows the manufacturing apparatus of the sheet | seat for electrodes used in the Example of this invention.
　本発明に用いる電極材料は、ハイブリッドキャパシタ用電極を得るために使用されるものであり、具体的には、電極活物質および結着剤を必須成分とし、必要に応じさらに導電材、分散材およびその他の添加剤などを含有することができる。 The electrode material used in the present invention is used for obtaining an electrode for a hybrid capacitor. Specifically, the electrode material includes an electrode active material and a binder as essential components, and if necessary, a conductive material, a dispersion material, and Other additives and the like can be contained.
　電極活物質とは電極内で電子の受け渡しをする物質である。 Electrode active material is a material that transfers electrons in the electrode.
　ハイブリッドキャパシタ用電極に用いる電極活物質には、正極用と負極用がある。ハイブリッドキャパシタ用電極の正極に用いる電極活物質としては、リチウムイオンと、例えばテトラフルオロボレートのようなアニオンを可逆的に担持できるものであれば良い。通常、電気二重層キャパシタで用いられる電極活物質が広く使用でき、炭素の同素体が用いられる。特に、同じ重量でもより広い面積の界面を形成することが可能なもの、すなわち比表面積の大きいものが好ましい。具体的には、比表面積が３０ｍ２／ｇ以上、好ましくは５００～５，０００ｍ２／ｇ、より好ましくは１，０００～３，０００ｍ２／ｇであることが好ましい。炭素の同素体の具体例としては、活性炭、ポリアセン、カーボンウィスカ及びグラファイト等が挙げられ、これらの粉末または繊維を使用することができる。好ましい正極活物質は活性炭であり、具体的にはフェノール系、レーヨン系、アクリル系、ピッチ系、又はヤシガラ系等の活性炭を挙げることができる。これら炭素の同素体は、正極活物質として、単独でまたは二種類以上を組み合わせて使用することができる。炭素の同素体を組み合わせて使用する場合は、平均粒径又は粒径分布の異なる二種類以上の炭素の同素体を組み合わせて使用してもよい。また、芳香族系縮合ポリマーの熱処理物であって、水素原子／炭素原子の原子比が０．５０～０．０５であるポリアセン系骨格構造を有するポリアセン系有機半導体（ＰＡＳ）も好適に使用できる。 Electrode active materials used for hybrid capacitor electrodes include positive electrodes and negative electrodes. The electrode active material used for the positive electrode of the hybrid capacitor electrode may be any material that can reversibly carry lithium ions and anions such as tetrafluoroborate. Usually, electrode active materials used in electric double layer capacitors can be widely used, and carbon allotropes are used. In particular, those capable of forming an interface having a larger area with the same weight, that is, those having a large specific surface area are preferred. Specifically, the specific surface area is 30 m 2 / g or more, preferably 500 to 5,000 m 2 / g, more preferably 1,000 to 3,000 m 2 / g. Specific examples of the allotrope of carbon include activated carbon, polyacene, carbon whisker, and graphite, and these powders or fibers can be used. A preferred positive electrode active material is activated carbon, and specific examples include phenol-based, rayon-based, acrylic-based, pitch-based, and coconut shell-based activated carbon. These carbon allotropes can be used alone or in combination of two or more as the positive electrode active material. When carbon allotropes are used in combination, two or more types of carbon allotropes having different average particle diameters or particle size distributions may be used in combination. Further, a polyacene organic semiconductor (PAS) having a polyacene skeleton structure, which is a heat-treated product of an aromatic condensation polymer and has an atomic ratio of hydrogen atom / carbon atom of 0.50 to 0.05, can be suitably used. .
　ハイブリッドキャパシタ用電極の負極に用いる電極活物質は、リチウムイオンを可逆的に担持できる物質から形成される。具体的には、リチウムイオン二次電池の負極で用いられる電極活物質は、広く使用できる。好ましくは、黒鉛、難黒鉛化炭素、ハードカーボン、コークス等の炭素材料、上記正極活物質としても記載したポリアセン系物質（ＰＡＳ）等を挙げることができる。これらの炭素材料及びＰＡＳは、フェノール樹脂等を炭化させ、必要に応じて賦活され、次いで粉砕したものが用いられる。 The electrode active material used for the negative electrode of the hybrid capacitor electrode is formed of a material that can reversibly carry lithium ions. Specifically, the electrode active material used in the negative electrode of the lithium ion secondary battery can be widely used. Preferable examples include carbon materials such as graphite, non-graphitizable carbon, hard carbon and coke, and polyacene-based materials (PAS) described as the positive electrode active material. These carbon materials and PAS are obtained by carbonizing a phenol resin or the like, activated as necessary, and then pulverized.
　ハイブリッドキャパシタ用電極に用いる電極活物質の形状は、粒状に整粒されたものが好ましい。粒子の形状が球形であると、電極成形時により高密度な電極が形成できる。 The shape of the electrode active material used for the hybrid capacitor electrode is preferably a granulated particle. When the shape of the particles is spherical, a higher density electrode can be formed during electrode molding.
　ハイブリッドキャパシタの電極に用いる電極活物質の体積平均粒子径は、正極、負極ともに通常０．１～１００μｍ、好ましくは１～５０μｍ、より好ましくは５～２０μｍである。 The volume average particle diameter of the electrode active material used for the electrode of the hybrid capacitor is usually 0.1 to 100 μm, preferably 1 to 50 μm, more preferably 5 to 20 μm for both the positive electrode and the negative electrode.
　これらの電極活物質は、それぞれ単独でまたは二種類以上を組み合わせて使用することができる。 These electrode active materials can be used alone or in combination of two or more.
　導電材とは、導電性を有し、電気二重層を形成し得る細孔を有さない粒子状の炭素の同素体からなり、ハイブリッドキャパシタ用電極（正極）の導電性を向上させるものである。導電材の具体例としては、ファーネスブラック、アセチレンブラック、及びケッチェンブラック（アクゾノーベルケミカルズベスローテンフェンノートシャップ社の登録商標）などの導電性カーボンブラック；天然黒鉛、人造黒鉛等の黒鉛；が挙げられる。これらの中でも、導電性カーボンブラックが好ましく、アセチレンブラックおよびファーネスブラックがより好ましい。 The conductive material is composed of an allotrope of particulate carbon that has conductivity and does not have pores that can form an electric double layer, and improves the conductivity of the electrode (positive electrode) for a hybrid capacitor. Specific examples of the conductive material include conductive carbon black such as furnace black, acetylene black, and ketjen black (registered trademark of Akzo Nobel Chemicals Bethloten Fennot Shap); graphite such as natural graphite and artificial graphite; Can be mentioned. Among these, conductive carbon black is preferable, and acetylene black and furnace black are more preferable.
　導電材の体積平均粒径は、正極用の電極活物質の体積平均粒径よりも小さいことが好ましく、通常０．００１～１０μｍ、好ましくは０．０５～５μｍ、より好ましくは０．０１～１μｍの範囲である。導電材の粒径がこの範囲にあると、より少ない使用量で高い導電性が得られる。 The volume average particle diameter of the conductive material is preferably smaller than the volume average particle diameter of the electrode active material for the positive electrode, usually 0.001 to 10 μm, preferably 0.05 to 5 μm, more preferably 0.01 to 1 μm. Range. When the particle size of the conductive material is within this range, high conductivity can be obtained with a smaller amount of use.
　これらの導電材は、それぞれ単独でまたは２種以上を組み合わせて用いることができる。導電材の量は、正極用の電極活物質１００重量部に対して、通常０．１～５０重量部、好ましくは０．５～１５重量部、より好ましくは１～１０重量部の範囲である。導電材の量がこの範囲にある電極を使用するとハイブリッドキャパシタの容量を高く且つ内部抵抗を低くすることができる。 These conductive materials can be used alone or in combination of two or more. The amount of the conductive material is usually in the range of 0.1 to 50 parts by weight, preferably 0.5 to 15 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the electrode active material for the positive electrode. . When an electrode having an amount of the conductive material within this range is used, the capacity of the hybrid capacitor can be increased and the internal resistance can be decreased.
　結着剤とは、電極活物質や導電材などを結着させることができる化合物である。例えば、フッ素系重合体、ジエン系重合体、アクリレート系重合体、ポリイミド、ポリアミド、ポリウレタン等の高分子化合物が挙げられ、好ましくはフッ素系重合体、ジエン系重合体、及びアクリレート系重合体が挙げられる。結着剤は、通常不導体なので、抵抗成分となる。前記分散型結着剤の中でも、フッ素系重合体、ジエン系重合体及びアクリレート系重合体は、抵抗増加傾向が少ないためより好ましい。その中でも、ジエン系重合体は、電極層の結着性が強いのでその使用量を減じることができる。 The binder is a compound that can bind an electrode active material, a conductive material, or the like. For example, polymer compounds such as fluorine-based polymers, diene-based polymers, acrylate-based polymers, polyimides, polyamides, and polyurethanes are preferable, and fluorine-based polymers, diene-based polymers, and acrylate-based polymers are preferable. It is done. Since the binder is usually a nonconductor, it becomes a resistance component. Among the dispersion-type binders, fluorine-based polymers, diene-based polymers, and acrylate-based polymers are more preferable because there is little tendency to increase resistance. Among them, the diene polymer can reduce the amount of use because the electrode layer has a strong binding property.
　フッ素系重合体はフッ素原子を含む単量体単位を含有する重合体である。フッ素系重合体中のフッ素を含有する単量体単位の割合は通常５０重量％以上である。フッ素系重合体の具体例としては、ポリテトラフルオロエチレン、ポリフッ化ビニリデン等のフッ素樹脂が挙げられ、ポリテトラフルオロエチレンが好ましい。 A fluoropolymer is a polymer containing a monomer unit containing a fluorine atom. The ratio of the monomer unit containing fluorine in the fluoropolymer is usually 50% by weight or more. Specific examples of the fluorine-based polymer include fluorine resins such as polytetrafluoroethylene and polyvinylidene fluoride, and polytetrafluoroethylene is preferable.
　ジエン系重合体は、共役ジエンの単独重合体もしくは共役ジエンを含む単量体混合物を重合して得られる共重合体、またはそれらの水素添加物である。前記単量体混合物における共役ジエンの割合は通常４０重量％以上、好ましくは５０重量％以上、より好ましくは６０重量％以上である。ジエン系重合体の具体例としては、ポリブタジエンやポリイソプレンなどの共役ジエン単独重合体；カルボキシ変性されていてもよいスチレン・ブタジエン共重合体（ＳＢＲ）などの芳香族ビニル・共役ジエン共重合体；アクリロニトリル・ブタジエン共重合体（ＮＢＲ）などのシアン化ビニル・共役ジエン共重合体；水素化ＳＢＲ、水素化ＮＢＲなどが挙げられる。 The diene polymer is a homopolymer of a conjugated diene or a copolymer obtained by polymerizing a monomer mixture containing a conjugated diene, or a hydrogenated product thereof. The proportion of the conjugated diene in the monomer mixture is usually 40% by weight or more, preferably 50% by weight or more, more preferably 60% by weight or more. Specific examples of the diene polymer include conjugated diene homopolymers such as polybutadiene and polyisoprene; aromatic vinyl / conjugated diene copolymers such as carboxy-modified styrene / butadiene copolymer (SBR); Examples include vinyl cyanide / conjugated diene copolymers such as acrylonitrile / butadiene copolymer (NBR); hydrogenated SBR, hydrogenated NBR, and the like.
　アクリレート系重合体は、アクリル酸エステルおよび／またはメタクリル酸エステルの単独重合体またはこれらを含む単量体混合物を重合して得られる共重合体である。前記単量体混合物におけるアクリル酸エステルおよび／またはメタクリル酸エステルの割合は通常４０重量％以上、好ましくは５０重量％以上、より好ましくは６０重量％以上である。 The acrylate polymer is a copolymer obtained by polymerizing a homopolymer of acrylic ester and / or methacrylic ester or a monomer mixture containing these. The ratio of acrylic acid ester and / or methacrylic acid ester in the monomer mixture is usually 40% by weight or more, preferably 50% by weight or more, more preferably 60% by weight or more.
　アクリレート系重合体の具体例としては、アクリル酸２－エチルヘキシル・メタクリル酸・アクリロニトリル・エチレングリコールジメタクリレート共重合体、アクリル酸２－エチルヘキシル・メタクリル酸・メタクリロニトリル・ジエチレングリコールジメタクリレート共重合体、アクリル酸２－エチルヘキシル・スチレン・メタクリル酸・エチレングリコールジメタクリレート共重合体、アクリル酸ブチル・アクリロニトリル・ジエチレングリコールジメタクリレート共重合体、およびアクリル酸ブチル・アクリル酸・トリメチロールプロパントリメタクリレート共重合体などの架橋型アクリレート系重合体；エチレン・アクリル酸メチル共重合体、エチレン・メタクリル酸メチル共重合体、エチレン・アクリル酸エチル共重合体、およびエチレン・メタクリル酸エチル共重合体などのエチレンとアクリル酸（またはメタクリル酸）エステルとの共重合体；上記エチレンとアクリル酸（またはメタクリル酸）エステルとの共重合体にラジカル重合性単量体をグラフトさせたグラフト重合体；などが挙げられる。なお、上記グラフト重合体に用いられるラジカル重合性単量体としては、例えば、メタクリル酸メチル、アクリロニトリル、メタクリル酸などが挙げられる。その他に、エチレン・アクリル酸共重合体、エチレン・メタクリル酸共重合体などのエチレンとアクリル酸（またはメタクリル酸）との共重合体等が結着剤として使用できる。 Specific examples of the acrylate polymer include 2-ethylhexyl acrylate / methacrylic acid / acrylonitrile / ethylene glycol dimethacrylate copolymer, 2-ethylhexyl acrylate / methacrylic acid / methacrylonitrile / diethylene glycol dimethacrylate copolymer, acrylic Crosslinking of 2-ethylhexyl acid / styrene / methacrylic acid / ethylene glycol dimethacrylate copolymer, butyl acrylate / acrylonitrile / diethylene glycol dimethacrylate copolymer, and butyl acrylate / acrylic acid / trimethylolpropane trimethacrylate copolymer Type acrylate polymer; ethylene / methyl acrylate copolymer, ethylene / methyl methacrylate copolymer, ethylene / ethyl acrylate copolymer, A copolymer of ethylene and acrylic acid (or methacrylic acid) such as ethylene / ethyl methacrylate copolymer; a radical polymerizable monomer in the above copolymer of ethylene and acrylic acid (or methacrylic acid) And the like, and the like. In addition, as a radically polymerizable monomer used for the said graft polymer, methyl methacrylate, acrylonitrile, methacrylic acid etc. are mentioned, for example. In addition, a copolymer of ethylene and acrylic acid (or methacrylic acid) such as an ethylene / acrylic acid copolymer and an ethylene / methacrylic acid copolymer can be used as a binder.
　結着剤は、その形状によって特に制限はないが、結着性が良く、また、作成したハイブリッドキャパシタの静電容量の低下や充放電の繰り返しによる劣化を抑えることができるため、粒子状であることが好ましい。粒子状の結着剤としては、例えば、ラテックスのごとき分散型結着剤の粒子が水に分散した状態のものや、このような分散液を乾燥して得られる粉末状のものが挙げられる。 The binder is not particularly limited depending on its shape, but has good binding properties and is particulate because it can suppress degradation of the produced hybrid capacitor due to decrease in capacitance and repeated charge / discharge. It is preferable. Examples of the particulate binder include those in which particles of a dispersion-type binder such as latex are dispersed in water, and powders obtained by drying such a dispersion.
　粒子状の結着剤の数平均粒径は、格別な限定はないが、通常は０．０００１～１００μｍ、好ましくは０．００１～１０μｍ、より好ましくは０．０１～１μｍである。結着剤の数平均粒径がこの範囲であるときは、少量の結着剤の使用でも優れた結着力を電極層に与えることができる。ここで、数平均粒径は、透過型電子顕微鏡写真で無作為に選んだ結着剤粒子１００個の径を測定し、その算術平均値として算出される個数平均粒径である。粒子の形状は球形、異形、どちらでもかまわない。 The number average particle diameter of the particulate binder is not particularly limited, but is usually 0.0001 to 100 μm, preferably 0.001 to 10 μm, more preferably 0.01 to 1 μm. When the number average particle diameter of the binder is within this range, an excellent binding force can be imparted to the electrode layer even when a small amount of the binder is used. Here, the number average particle diameter is a number average particle diameter calculated as an arithmetic average value obtained by measuring the diameter of 100 binder particles randomly selected in a transmission electron micrograph. The shape of the particles can be either spherical or irregular.
　結着剤のガラス転移温度（Ｔｇ）は、－８０℃～５０℃が好ましく、より好ましくは－５０℃～２０℃である。結着剤のガラス転移温度（Ｔｇ）が前記範囲であることにより、結着性と柔軟性のバランスに優れた電極層を得ることができる。 The glass transition temperature (Tg) of the binder is preferably −80 ° C. to 50 ° C., more preferably −50 ° C. to 20 ° C. When the glass transition temperature (Tg) of the binder is in the above range, an electrode layer having an excellent balance between binding properties and flexibility can be obtained.
　これら結着剤は単独で又は二種以上を組み合わせて用いることができる。結着剤の使用量は、電極活物質１００重量部に対して、通常は０．１～５０重量部、好ましくは０．５～２０重量部、より好ましくは１～１０重量部の範囲である。 These binders can be used alone or in combination of two or more. The amount of the binder used is usually in the range of 0.1 to 50 parts by weight, preferably 0.5 to 20 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the electrode active material. .
　電極材料にはその他に分散材を含有していることが好ましい。分散材とはスラリーの溶媒に溶解させて用いられ、電極活物質、導電材等を溶媒に均一に分散させる作用をさらに有するものである。例えば、カルボキシメチルセルロース、メチルセルロース、エチルセルロース、ヒドロキシプロピルセルロースなどのセルロース系ポリマー、ならびにこれらのアンモニウム塩またはアルカリ金属塩；ポリアクリル酸（またはメタクリル酸）ナトリウムなどのポリアクリル酸（またはメタクリル酸）塩；ポリビニルアルコール、変性ポリビニルアルコール、ポリエチレンオキシド；ポリビニルピロリドン、ポリカルボン酸、酸化スターチ、リン酸スターチ、カゼイン、各種変性デンプン、キチン、キトサン誘導体などが挙げられる。これらの分散材は、それぞれ単独でまたは２種以上を組み合わせて使用できる。中でも、セルロース系ポリマーが好ましく、カルボキシメチルセルロースまたはそのアンモニウム塩もしくはアルカリ金属塩が特に好ましい。 It is preferable that the electrode material further contains a dispersing agent. The dispersing material is used by being dissolved in a slurry solvent, and further has an action of uniformly dispersing the electrode active material, the conductive material and the like in the solvent. For example, cellulosic polymers such as carboxymethyl cellulose, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, and ammonium salts or alkali metal salts thereof; polyacrylic acid (or methacrylic acid) salts such as sodium polyacrylic acid (or methacrylic acid); polyvinyl Examples include alcohol, modified polyvinyl alcohol, polyethylene oxide; polyvinyl pyrrolidone, polycarboxylic acid, oxidized starch, phosphate starch, casein, various modified starches, chitin, and chitosan derivatives. These dispersing agents can be used alone or in combination of two or more. Among these, a cellulose polymer is preferable, and carboxymethyl cellulose or an ammonium salt or an alkali metal salt thereof is particularly preferable.
　分散材の使用量は、格別な限定はないが、電極活物質１００重量部に対して、通常は０．１～１０重量部、好ましくは０．５～５重量部、より好ましくは０．８～２重量部の範囲である。分散材を用いることで、スラリー中の固形分の沈降や凝集を抑制できる。また、噴霧乾燥時のアトマイザーの詰まりを防止することができるので、噴霧乾燥を安定して連続的に行うことができる。また、後述する複合粒子表面の表面平均空隙率を上げるため、具体的には表面平均空隙率を１５％以上にするためには、重量平均分子量が３０万以上の分散材を使用することが好ましい。 The amount of the dispersing agent used is not particularly limited, but is usually 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, more preferably 0.8 parts per 100 parts by weight of the electrode active material. It is in the range of up to 2 parts by weight. By using the dispersing material, it is possible to suppress sedimentation and aggregation of the solid content in the slurry. Moreover, since the clogging of the atomizer at the time of spray drying can be prevented, spray drying can be performed stably and continuously. Further, in order to increase the surface average porosity of the composite particle surface described later, specifically, in order to increase the surface average porosity to 15% or more, it is preferable to use a dispersion material having a weight average molecular weight of 300,000 or more. .
　その他の添加剤としては、例えば、界面活性剤がある。界面活性剤としては、アニオン性、カチオン性、ノニオン性、ノニオニックアニオンなどの両性の界面活性剤が挙げられるが、中でもアニオン性若しくはノニオン性の界面活性剤で熱分解しやすいものが好ましい。 Other additives include, for example, surfactants. Examples of the surfactant include amphoteric surfactants such as anionic, cationic, nonionic, and nonionic anions. Among them, anionic or nonionic surfactants that are easily thermally decomposed are preferable.
　界面活性剤は単独で又は二種以上を組み合わせて用いることができる。界面活性剤の量は、格別な限定はないが、電極活物質１００重量部に対して０～５０重量部、好ましくは０．１～１０重量部、より好ましくは０．５～５重量部の範囲である。 Surfactants can be used alone or in combination of two or more. The amount of the surfactant is not particularly limited, but is 0 to 50 parts by weight, preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the electrode active material. It is a range.
　本発明に使用される電極材料は、上記電極活物質および結着剤を必須成分として、必要に応じて導電材、分散材、その他の添加剤を含有してなる。好適に用いられる電極材料は上記成分を複合して含有する粒子形状のもの（以下、「複合粒子」ということがある。）である。この複合粒子は、通常、電極活物質および結着剤を少なくとも含有し、前記電極活物質が結着剤により結着されてなるもので構成されていることが好ましい。 The electrode material used in the present invention contains the above-described electrode active material and binder as essential components, and contains a conductive material, a dispersing material, and other additives as necessary. A suitably used electrode material is in the form of particles containing the above components in a composite (hereinafter sometimes referred to as “composite particles”). It is preferable that the composite particles usually contain at least an electrode active material and a binder, and the electrode active material is bound by a binder.
　複合粒子の製造方法は特に制限されず、噴霧乾燥造粒法、転動層造粒法、圧縮型造粒法、攪拌型造粒法、押出し造粒法、破砕型造粒法、流動層造粒法、流動層多機能型造粒法、および溶融造粒法などの公知の造粒法により製造することができる。中でも、表面付近に結着剤および導電助剤が偏在した複合粒子を容易に得られるので、噴霧乾燥造粒法が好ましい。噴霧乾燥造粒法で得られる複合粒子を用いると、本発明の電極を高い生産性で得ることができる。また、該電極の内部抵抗をより低減することができる。 The production method of the composite particles is not particularly limited, and is a spray drying granulation method, a rolling bed granulation method, a compression granulation method, a stirring granulation method, an extrusion granulation method, a crushing granulation method, a fluidized bed granulation method. It can be produced by a known granulation method such as a granulation method, a fluidized bed multifunctional granulation method, or a melt granulation method. Among these, the spray-drying granulation method is preferable because composite particles in which the binder and the conductive auxiliary agent are unevenly distributed near the surface can be easily obtained. When composite particles obtained by the spray drying granulation method are used, the electrode of the present invention can be obtained with high productivity. In addition, the internal resistance of the electrode can be further reduced.
　本発明に好適に使用される複合粒子は、電極活物質及び結着剤を含むスラリーを噴霧乾燥して得られた粒子であることが好ましい。前記複合粒子が、上記電極活物質及び結着剤を含むスラリーを噴霧乾燥して得られた粒子であることにより、本発明の電極をより高い生産性で得ることができ、かつ該電極の内部抵抗をより低減することができる。 The composite particles suitably used in the present invention are preferably particles obtained by spray drying a slurry containing an electrode active material and a binder. When the composite particles are particles obtained by spray drying a slurry containing the electrode active material and the binder, the electrode of the present invention can be obtained with higher productivity, and the inside of the electrode Resistance can be further reduced.
　前記スラリーは、電極活物質及び結着剤の必須成分の他に、導電材、分散材やその他の添加剤などの任意成分とを、溶媒に分散または溶解させることにより得ることができる。 The slurry can be obtained by dispersing or dissolving an optional component such as a conductive material, a dispersing agent, and other additives in a solvent in addition to the essential components of the electrode active material and the binder.
　複合粒子を得るためのスラリーに用いる溶媒として、通常、水が用いられるが、有機溶媒を用いてもよい。有機溶媒としては、例えば、メチルアルコール、エチルアルコール、プロピルアルコールなどのアルキルアルコール類；アセトン、メチルエチルケトンなどのアルキルケトン類；テトラヒドロフラン、ジオキサン、ジグライム等のエーテル類；ジエチルホルムアミド、ジメチルアセトアミド、Ｎ－メチル－２－ピロリドン、ジメチルイミダゾリジノン等のアミド類；ジメチルスルホキサイド、スルホラン等のイオウ系溶剤；などが挙げられるが、アルコール類が好ましい。水よりも沸点の低い有機溶媒を併用すると、噴霧乾燥法による造粒時に、乾燥速度を速くすることができる。また、分散型結着剤の分散性又は溶解型樹脂の溶解性が溶媒の種類によって変るので、スラリーの粘度や流動性を有機溶媒の量又は種類を選択することにより調整し、噴霧乾燥の生産効率を向上させることができる。 As the solvent used in the slurry for obtaining composite particles, water is usually used, but an organic solvent may be used. Examples of the organic solvent include alkyl alcohols such as methyl alcohol, ethyl alcohol and propyl alcohol; alkyl ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran, dioxane and diglyme; diethylformamide, dimethylacetamide, N-methyl- Examples include amides such as 2-pyrrolidone and dimethylimidazolidinone; sulfur solvents such as dimethyl sulfoxide and sulfolane; and alcohols are preferable. When an organic solvent having a lower boiling point than water is used in combination, the drying rate can be increased during granulation by the spray drying method. In addition, since the dispersibility of the dispersion-type binder or the solubility of the soluble resin varies depending on the type of solvent, the viscosity and fluidity of the slurry are adjusted by selecting the amount or type of organic solvent, and spray drying production Efficiency can be improved.
　スラリーを調製するときに使用する溶媒の量は、スラリーの固形分濃度が、通常は１～５０重量％、好ましくは５～５０重量％、より好ましくは１０～３０重量％の範囲となるような量である。 The amount of the solvent used when preparing the slurry is such that the solid content concentration of the slurry is usually in the range of 1 to 50% by weight, preferably 5 to 50% by weight, more preferably 10 to 30% by weight. Amount.
　電極活物質及び結着剤の必須成分、並びに前記任意成分を溶媒に分散又は溶解する方法又は手順は特に限定されず、例えば、溶媒に電極活物質、導電材、結着剤、及び前記他の任意成分を添加し混合する方法；溶媒に分散させた結着剤（例えば、ラテックス）を添加して混合し、電極活物質、導電材及び前記任意成分を添加して混合する方法；電極活物質、導電材及び前記他の任意成分を溶媒に分散させたものを、結着剤に添加して混合する方法などが挙げられる。混合の手段としては、例えば、ボールミル、サンドミル、ビーズミル、顔料分散機、らい潰機、超音波分散機、ホモジナイザー、プラネタリーミキサーなどの混合機器が挙げられる。混合は、通常、室温～８０℃の範囲で、１０分間～数時間行う。 There are no particular limitations on the essential components of the electrode active material and the binder, and the method or procedure for dispersing or dissolving the optional components in the solvent. For example, the electrode active material, the conductive material, the binder, and the other Method of adding and mixing optional components; Method of adding and mixing a binder (for example, latex) dispersed in a solvent, and adding and mixing an electrode active material, a conductive material and the optional component; And a method in which a conductive material and other optional components dispersed in a solvent are added to a binder and mixed. Examples of the mixing means include mixing equipment such as a ball mill, a sand mill, a bead mill, a pigment disperser, a crusher, an ultrasonic disperser, a homogenizer, and a planetary mixer. Mixing is usually carried out in the range of room temperature to 80 ° C. for 10 minutes to several hours.
　噴霧乾燥法は、熱風中にスラリーを噴霧して乾燥する方法である。噴霧乾燥法に用いる装置の代表例としてアトマイザーが挙げられる。アトマイザーは、回転円盤方式と加圧方式との二種類の装置がある。回転円盤方式は、高速回転する円盤のほぼ中央にスラリーを導入し、円盤の遠心力によってスラリーが円盤の外に放たれ、その際に霧状にして乾燥する方式である。 The spray drying method is a method in which slurry is sprayed and dried in hot air. A typical example of the apparatus used for the spray drying method is an atomizer. There are two types of atomizers: a rotating disk method and a pressure method. The rotating disk system is a system in which slurry is introduced almost at the center of a disk that rotates at high speed, and the slurry is released from the disk by the centrifugal force of the disk, and in that case, the slurry is dried in the form of a mist.
　円盤の回転速度は円盤の大きさに依存するが、通常は５，０００～３０，０００ｒｐｍ、好ましくは１５，０００～３０，０００ｒｐｍである。一方、加圧方式は、スラリーを加圧してノズルから霧状にして乾燥する方式である。 The rotational speed of the disk depends on the size of the disk, but is usually 5,000 to 30,000 rpm, preferably 15,000 to 30,000 rpm. On the other hand, the pressurization method is a method in which the slurry is pressurized and sprayed from a nozzle to be dried.
　噴霧されるスラリーの温度は、通常は室温であるが、加温して室温以上にしたものであってもよい。噴霧乾燥時の熱風温度は、通常８０～２５０℃、好ましくは１００～２００℃である。噴霧乾燥法において、熱風の吹き込み方法は特に制限されず、例えば、熱風と噴霧方向が横方向に並流する方式、乾燥塔頂部で噴霧され熱風と共に下降する方式、噴霧した滴と熱風が向流接触する方式、噴霧した滴が最初熱風と並流し次いで重力落下して向流接触する方式などが挙げられる。さらに、複合粒子の表面を硬化させるために加熱処理する。熱処理温度は、通常８０～３００℃である。 The temperature of the slurry to be sprayed is usually room temperature, but it may be heated to room temperature or higher. The hot air temperature at the time of spray drying is usually 80 to 250 ° C., preferably 100 to 200 ° C. In the spray drying method, the method of blowing hot air is not particularly limited. Examples include a contact method, and a method in which sprayed droplets first flow in parallel with hot air and then drop by gravity to make countercurrent contact. Furthermore, heat treatment is performed to cure the surface of the composite particles. The heat treatment temperature is usually 80 to 300 ° C.
　本発明に好適に用いる複合粒子の形状は、実質的に球形であることが好ましい。すなわち、複合粒子の短軸径をＬｓ、長軸径をＬｌ、Ｌａ＝（Ｌｓ＋Ｌｌ）／２とし、（１－（Ｌｌ－Ｌｓ）／Ｌａ）×１００の値を球形度（％）としたとき、球形度が８０％以上であることが好ましく、より好ましくは９０％以上である。ここで、短軸径Ｌｓおよび長軸径Ｌｌは、透過型電子顕微鏡写真像より測定される値である。 The shape of the composite particles suitably used in the present invention is preferably substantially spherical. That is, when the short axis diameter of the composite particles is Ls, the long axis diameter is Ll, La = (Ls + Ll) / 2, and the value of (1− (Ll−Ls) / La) × 100 is sphericity (%). The sphericity is preferably 80% or more, more preferably 90% or more. Here, the minor axis diameter Ls and the major axis diameter Ll are values measured from a transmission electron micrograph image.
　本発明に好適に用いる複合粒子の体積平均粒子径は、通常１０～１００μｍ、好ましくは２０～８０μｍ、より好ましくは３０～６０μｍの範囲である。体積平均粒子径は、レーザ回折式粒度分布測定装置を用いて測定することができる。 The volume average particle diameter of the composite particles suitably used in the present invention is usually in the range of 10 to 100 μm, preferably 20 to 80 μm, more preferably 30 to 60 μm. The volume average particle diameter can be measured using a laser diffraction particle size distribution measuring apparatus.
　本発明に好適に用いる複合粒子は、表面平均空隙率が、好ましくは１５％以上、より好ましくは２０％以上、さらに好ましくは２０％以上４０％以下である。ここで、「表面平均空隙率」は、複合粒子１つあたり、５視野以上（それぞれ異なる視野で）で、かつ１０粒子以上について、複合粒子の表面において、０．１μｍ２以上の空隙の見掛けの面積を測定し、全視野面積に対する空隙の見掛けの表面積の割合（％）（以下、「空隙率」と記載することがある）の平均値として得られる値である。複合粒子の表面平均空隙率が１５％未満であると、複合粒子中の電解質イオンの拡散抵抗が大きくなり、これを用いて得られる電極の抵抗が大きくなる。本発明に好適に用いる複合粒子の表面平均空隙率を１５％以上にするためには、複合粒子を作製する際に、重量平均分子量が３０万以上の分散材を使用することにより達成可能である。 The composite particles suitably used in the present invention have a surface average porosity of preferably 15% or more, more preferably 20% or more, and further preferably 20% or more and 40% or less. Here, the “surface average porosity” is an apparent area of voids of 0.1 μm 2 or more on the surface of the composite particle for 5 particles or more (each with different fields of view) and 10 particles or more per composite particle. Is a value obtained as an average value of the ratio (%) of the apparent surface area of the void to the entire visual field area (hereinafter sometimes referred to as “void ratio”). When the surface average porosity of the composite particles is less than 15%, the diffusion resistance of the electrolyte ions in the composite particles increases, and the resistance of the electrode obtained by using this increases. In order to increase the surface average porosity of the composite particles suitably used in the present invention to 15% or more, it can be achieved by using a dispersion material having a weight average molecular weight of 300,000 or more when producing the composite particles. .
　具体的には、表面平均空隙率は、本発明で好適に用いる複合粒子について、電子顕微鏡写真を撮影し、任意に選択した１粒子当たり、異なる５視野以上を観察し、面積が０．１μｍ２以上の連続した空隙の見掛け上の表面積を測定し、１０粒子以上について同様の測定を行い、得られた空隙率の平均値として算出する。なお、空隙の見掛け上の表面積とは、電子顕微鏡写真上で観察される空隙の開口部の表面積相当の面積であり、空隙の細孔内の面積等を考慮に入れた実際の面積ではない。個々の複合粒子を見た場合には、空隙率が１５％未満の複合粒子も含まれることがあるが、空隙率が１５％以上の粒子を多く含むため、全体の表面平均空隙率は、上記のように高くなる。 Specifically, the surface average porosity is obtained by taking an electron micrograph of the composite particles suitably used in the present invention, observing five or more different fields per arbitrarily selected particle, and an area of 0.1 μm 2 or more. The apparent surface area of the continuous voids is measured, the same measurement is performed for 10 particles or more, and the average value of the obtained void ratios is calculated. The apparent surface area of the void is an area corresponding to the surface area of the opening of the void observed on the electron micrograph, and is not an actual area taking into consideration the area in the pores of the void. When individual composite particles are seen, composite particles having a porosity of less than 15% may be included, but since the porosity includes a large number of particles having a porosity of 15% or more, the overall surface average porosity is As high as
　本発明に好適な複合粒子は、微小圧縮試験機によって荷重速度０．９ｍＮ／ｓｅｃで最大荷重９．８ｍＮまで圧縮したときの粒径変位率が通常５～７０％、好ましくは２０～５０％である。粒径変位率は、複合粒子の圧縮前の粒径Ｄ０に対する、圧縮による粒径の減少量（ΔＤ＝Ｄ０－Ｄ１）の割合（＝ΔＤ／Ｄ０×１００）である。なお、Ｄ１は荷重を掛けているときの粒径で荷重量に応じて変化する値である。 The composite particles suitable for the present invention usually have a particle size displacement rate of 5 to 70%, preferably 20 to 50% when compressed to a maximum load of 9.8 mN at a load speed of 0.9 mN / sec using a micro compression tester. is there. The particle size displacement rate is the ratio (= ΔD / D0 × 100) of the amount of particle size reduction (ΔD = D0−D1) due to compression to the particle size D0 before compression of the composite particles. In addition, D1 is a value which changes according to a load amount with a particle size when applying a load.
　また、本発明に好適に用いられる複合粒子は、微小圧縮試験機によって荷重速度０．９ｍＮ／秒で最大荷重９．８ｍＮまで圧縮したときの、単位秒あたりの粒径変位率変化量が好ましくは２５％以下、より好ましくは１０％以下、特に好ましくは７％以下である。単位秒あたりの粒径変位率変化量は、荷重速度０．９ｍＮ／秒で荷重が増えていったときの粒径変位率の単位秒あたりの変化量である。微小圧縮試験機によって測定される最大荷重９．８ｍＮまで圧縮したときの粒径変位率は、複合粒子の形状維持力を示すために必要な数値である。該粒径変位率が小さ過ぎると、加圧によってもほとんど複合粒子が変形しないので、粒子同士の接触面積が小さく、導電性が高くならない。一方、粒径変位率が大き過ぎると、複合粒子が圧壊し、複合粒子中に形成された導電材及び電極活物質によるネットワークが壊れ、導電性が低下する。また、単位秒あたりの粒径変位率変化量は、圧壊の有無を判断する一指標である。圧壊が起きると、粒径が急激に小さくなるので、単位秒あたりの粒径変位率変化量が２５％を超える。圧壊によって、複合粒子中に形成された導電材及び電極活物質によるネットワークが壊れ、導電性が低下する。最大荷重９．８ｍＮまで圧縮したときの粒径変位率が５～７０％である複合粒子は、適度な柔らかさを持つので、粒子同士の接触面積が大きい。そして、圧壊しないので、導電材及び電極活物質のネットワークが維持される。これら複合粒子は単独で又は二種以上を組み合わせて用いることができる。 In addition, the composite particles suitably used in the present invention preferably have a change amount of particle size displacement rate per unit second when compressed to a maximum load of 9.8 mN at a load speed of 0.9 mN / sec by a micro compression tester. It is 25% or less, more preferably 10% or less, and particularly preferably 7% or less. The change amount of the particle size displacement rate per unit second is the change amount per unit second of the particle size change rate when the load is increased at a load speed of 0.9 mN / second. The particle size displacement rate when compressed to a maximum load of 9.8 mN measured by a micro-compression tester is a numerical value necessary to show the shape maintenance force of the composite particles. If the particle size displacement rate is too small, the composite particles are hardly deformed even by pressurization, so that the contact area between the particles is small and the conductivity is not increased. On the other hand, when the particle size displacement rate is too large, the composite particles are crushed, the network formed by the conductive material and the electrode active material formed in the composite particles is broken, and the conductivity is lowered. Further, the change amount of the particle size displacement rate per unit second is an index for determining the presence or absence of crushing. When crushing occurs, the particle size decreases rapidly, so the amount of change in particle size displacement rate per unit second exceeds 25%. By crushing, the network formed by the conductive material and the electrode active material formed in the composite particles is broken, and the conductivity is lowered. Composite particles having a particle size displacement rate of 5 to 70% when compressed to a maximum load of 9.8 mN have moderate softness, so that the contact area between the particles is large. And since it does not crush, the network of an electroconductive material and an electrode active material is maintained. These composite particles can be used alone or in combination of two or more.
　本発明に使用される多孔化集電体とは、ハイブリッドキャパシタで必要な負極及び／又は正極にリチウムイオンの一括ドープを可能にする表裏貫通孔を有する、集電機能を有する電極基体である。その材料としては、例えば、金属、炭素、導電性高分子などを用いることができ、好適には金属が用いられる。集電体用金属としては、通常、アルミニウム、白金、ニッケル、タンタル、チタン、ステンレス鋼、銅、その他の合金等が使用される。これらの中で導電性、耐電圧性の面からアルミニウムまたはアルミニウム合金を使用するのが好ましい。表裏貫通孔の形状としては、四角形、菱形、亀甲形状、六角形、丸形、星形、十文字形などが挙げられる。多孔化集電体の具体例としては、平板を菱形や亀甲形の網状に展開して得られるエキスパンドメタル、平板に穿孔して得られるパンチングメタル、金属線や金属帯を平織り若しくはあや織りして又はクリンプ金属線を嵌め合わせて得られる金網などが挙げられる。 The porous current collector used in the present invention is an electrode substrate having a current collecting function having front and back through-holes capable of batch doping of lithium ions on a negative electrode and / or a positive electrode necessary for a hybrid capacitor. As the material, for example, metal, carbon, conductive polymer, and the like can be used, and metal is preferably used. As the current collector metal, aluminum, platinum, nickel, tantalum, titanium, stainless steel, copper, other alloys and the like are usually used. Among these, it is preferable to use aluminum or an aluminum alloy in terms of conductivity and voltage resistance. Examples of the shape of the front and back through holes include a rectangle, a rhombus, a turtle shell shape, a hexagon, a round shape, a star shape, and a cross shape. Specific examples of porous collectors include expanded metal obtained by expanding a flat plate into a rhombus or turtle shell-shaped net, punching metal obtained by perforating a flat plate, and plain or twilled metal wires or metal bands. Or the metal net | network etc. which are obtained by fitting a crimp metal wire are mentioned.
　本発明に使用される多孔化集電体の開口率は、特に規定はされないが、強度と成形速度を高くできるので、好ましくは１０～９０面積％、より好ましくは４０～６０面積％である。開口径は、特に規定はされないが、成形速度を高くできるので、通常０．１～１０μｍ、より好ましくは１～５μｍである。ここでいう開口径とは、開口部の外接円の直径である。外接円の直径は、レーザー顕微鏡や工具顕微鏡などにより集電体の表面観察を行い、開口部に外接円をフィッティングさせ、それを平均化したものである。多孔化集電体の厚さは、使用目的に応じて適宜選択されるが、高い強度と低抵抗とを両立するとの観点から、好ましくは１０～１００μｍ、より好ましくは５０～１００μｍである。 Although the aperture ratio of the porous current collector used in the present invention is not particularly defined, it is preferably 10 to 90 area%, more preferably 40 to 60 area%, because the strength and molding speed can be increased. The opening diameter is not particularly specified, but is usually 0.1 to 10 μm, more preferably 1 to 5 μm because the molding speed can be increased. The opening diameter here is a diameter of a circumscribed circle of the opening. The diameter of the circumscribed circle is obtained by observing the surface of the current collector with a laser microscope or a tool microscope, fitting the circumscribed circle to the opening, and averaging the results. The thickness of the porous current collector is appropriately selected according to the purpose of use, but is preferably 10 to 100 μm, more preferably 50 to 100 μm from the viewpoint of achieving both high strength and low resistance.
　また集電体は、その表面に導電性接着剤を塗布したものを用いてもよい。導電性接着剤は、導電助剤の粉末と結着剤と、必要に応じ添加される分散剤とを水または有機溶媒中に分散させたものである。導電性接着剤の導電助剤としては、銀、ニッケル、金、黒鉛、アセチレンブラック、ケッチェンブラックが挙げられ、好ましくは黒鉛、アセチレンブラックである。導電性接着剤の結着剤としては、上記本発明の電極材料に使用される結着剤として例示したものをいずれも使用できる。また、水ガラス、エポキシ樹脂、ポリアミドイミド樹脂、ウレタン樹脂等も用いることができ、それぞれ単独でまたは２種以上を組み合わせて使用できる。導電性接着剤の結着剤は好ましくは、アクリレート系重合体、カルボキシメチルセルロースのアンモニウム塩またはアルカリ金属塩、水ガラス、ポリアミドイミド樹脂である。また、導電性接着剤の分散剤としては、上記本発明の電極の電極層に使用してもよい分散材、または界面活性剤を用いることができる。 Further, the current collector may be one obtained by applying a conductive adhesive on the surface thereof. The conductive adhesive is obtained by dispersing a conductive auxiliary powder, a binder, and a dispersant added as necessary in water or an organic solvent. Examples of the conductive assistant for the conductive adhesive include silver, nickel, gold, graphite, acetylene black, and ketjen black, and graphite and acetylene black are preferable. As the binder of the conductive adhesive, any of those exemplified as the binder used in the electrode material of the present invention can be used. Moreover, water glass, an epoxy resin, a polyamideimide resin, a urethane resin, etc. can also be used, and each can be used individually or in combination of 2 or more types. The binder of the conductive adhesive is preferably an acrylate polymer, an ammonium salt or alkali metal salt of carboxymethyl cellulose, water glass, or polyamideimide resin. Moreover, as a dispersing agent of a conductive adhesive, a dispersing agent or a surfactant that may be used for the electrode layer of the electrode of the present invention can be used.
　本発明では、上記多孔化集電体上の少なくとも一表面に上記電極材料を供給する。電極材料を供給する工程で用いられるフィーダーは、特に限定されないが、複合粒子を定量的に供給できる定量フィーダーであることが好ましい。ここで、定量的に供給できるとは、かかるフィーダーを用いて電極材料を連続的に供給し、一定間隔で供給量を複数回測定し、その測定値の平均値ｍと標準偏差σｍから求められるＣＶ値（＝σｍ／ｍ×１００）が４以下であることをいう。本発明に用いられる定量フィーダーは、ＣＶ値が好ましくは２以下である。定量フィーダーの具体例としては、テーブルフィーダー、ロータリーフィーダーなどの重力供給機、スクリューフィーダー、ベルトフィーダーなどの機械力供給機などが挙げられる。これらのうちロータリーフィーダーが好適である。 In the present invention, the electrode material is supplied to at least one surface of the porous current collector. The feeder used in the step of supplying the electrode material is not particularly limited, but is preferably a quantitative feeder capable of supplying composite particles quantitatively. Here, being able to supply quantitatively means that the electrode material is continuously supplied using such a feeder, the supply amount is measured a plurality of times at regular intervals, and the average value m of the measured values and the standard deviation σm are obtained. It means that the CV value (= σm / m × 100) is 4 or less. The quantitative feeder used in the present invention preferably has a CV value of 2 or less. Specific examples of the quantitative feeder include a gravity feeder such as a table feeder and a rotary feeder, and a mechanical force feeder such as a screw feeder and a belt feeder. Of these, the rotary feeder is preferred.
　次いで、前記多孔化集電体と供給された電極材料とを一対のロールで加圧して、多孔化集電体上に電極層を形成する。この工程では、必要に応じ加温された前記電極材料が、一対のロールでシート状の電極層に成形される。供給される電極材料の温度は、好ましくは４０～１６０℃、より好ましくは７０～１４０℃である。この温度範囲にある電極材料を用いると、プレス用ロールの表面で電極材料の滑りがなく、電極材料が連続的かつ均一にプレス用ロールに供給されるので、膜厚が均一で、電極密度のばらつきが小さい、電気化学素子電極用シートを得ることができる。 Next, the porous current collector and the supplied electrode material are pressurized with a pair of rolls to form an electrode layer on the porous current collector. In this step, the electrode material heated as necessary is formed into a sheet-like electrode layer by a pair of rolls. The temperature of the electrode material supplied is preferably 40 to 160 ° C., more preferably 70 to 140 ° C. When an electrode material in this temperature range is used, there is no slip of the electrode material on the surface of the press roll, and the electrode material is continuously and uniformly supplied to the press roll. An electrochemical element electrode sheet with small variations can be obtained.
　成形時の温度は、通常０～２００℃であり、結着剤の融点またはガラス転移温度より高いことが好ましく、融点またはガラス転移温度より２０℃以上高いことがより好ましい。ロールを用いる場合の成形速度は、通常１０ｍ／分以上、成形性が高く薄膜化が容易なので、好ましくは２０～２００ｍ／分、さらに好ましくは３０～８０ｍ／分である。ここでいう成形速度とは、ロールの回転速度を意味する。またプレス用ロール間のプレス線圧は、特に規定はされないが、電極強度を高くできるので、好ましくは０．２～３０ｋＮ／ｃｍ、より好ましくは０．５～１０ｋＮ／ｃｍである。 The molding temperature is usually 0 to 200 ° C., preferably higher than the melting point or glass transition temperature of the binder, and more preferably 20 ° C. higher than the melting point or glass transition temperature. When a roll is used, the forming speed is usually 10 m / min or more, and it is preferably 20 to 200 m / min, and more preferably 30 to 80 m / min, because the moldability is high and thinning is easy. The forming speed here means the rotational speed of the roll. The press linear pressure between the press rolls is not particularly defined, but is preferably 0.2 to 30 kN / cm, more preferably 0.5 to 10 kN / cm because the electrode strength can be increased.
　本発明の製法では、前記一対のロールの配置は特に限定されないが、略水平または略垂直に配置されることが好ましい。略水平に配置する場合は、前記多孔化集電体を一対のロール間に連続的に供給し、該ロールの少なくとも一方に電極材料を供給することで、多孔化集電体とロールとの間隙に電極材料が供給され、加圧により電極層を形成できる。略垂直に配置する場合は、前記多孔化集電体を水平方向に搬送させ、該集電体上に電極材料を供給し、電極材料層を形成する。供給された電極材料層を必要に応じブレード等で均一にした後、該集電体を一対のロール間に供給し、加圧により電極層を形成できる。この場合において、一対のロール間に供給される電極材料層の厚さは、（前記一対のロールのロール間隙）／（多孔化集電体厚み＋電極材料層の厚さ）で表される値で、成形性に優れるとの観点から、好ましくは０．０１～１であり、より好ましくは０．０５～０．７５、特に好ましくは０．１～０．５である。 In the production method of the present invention, the arrangement of the pair of rolls is not particularly limited, but is preferably arranged substantially horizontally or substantially vertically. When arranged substantially horizontally, the porous current collector is continuously supplied between a pair of rolls, and an electrode material is supplied to at least one of the rolls, so that the gap between the porous current collector and the rolls is increased. An electrode material is supplied to the electrode layer, and an electrode layer can be formed by pressurization. In the case of disposing substantially vertically, the porous current collector is conveyed in the horizontal direction, an electrode material is supplied onto the current collector, and an electrode material layer is formed. After the supplied electrode material layer is made uniform with a blade or the like as necessary, the current collector is supplied between a pair of rolls, and the electrode layer can be formed by pressurization. In this case, the thickness of the electrode material layer supplied between the pair of rolls is a value represented by (roll gap between the pair of rolls) / (thickness of the porous current collector + thickness of the electrode material layer). From the viewpoint of excellent moldability, it is preferably 0.01 to 1, more preferably 0.05 to 0.75, and particularly preferably 0.1 to 0.5.
　成形した成形体の厚みのばらつきを無くし、密度を上げて高容量化をはかるために、必要に応じて更に後加圧を行っても良い。後加圧の方法は、ロールによるプレス工程が一般的である。ロールプレス工程では、２本の円柱状のロールをせまい間隔で平行に上下にならべ、それぞれを反対方向に回転させて、その間に電極をかみこませ加圧する。ロールは加熱又は冷却等、温度調節しても良い。 ¡Post-pressurization may be further performed as necessary in order to eliminate variations in the thickness of the molded body and increase the density and increase the capacity. The post-pressing method is generally a press process using a roll. In the roll press process, two cylindrical rolls are arranged in parallel at a narrow interval in the vertical direction, and each is rotated in the opposite direction. The temperature of the roll may be adjusted by heating or cooling.
　本発明の製造方法で得られるハイブリッドキャパシタ用電極は、非プロトン性有機溶媒電解質溶液を形成する非プロトン性有機溶媒を電解液溶媒として用いるハイブリッドキャパシタに好適に用いられる。非プロトン性有機溶媒としては、例えばエチレンカーボネート、プロピレンカーボネート、ジメチルカーボネート、ジエチルカーボネート、γ－ブチロラクトン、アセトニトリル、ジメトキシエタン、テトラヒドロフラン、ジオキソラン、塩化メチレン、スルホラン等が挙げられる。更に、これら非プロトン性有機溶媒の二種以上を混合した混合液を用いることもできる。 The electrode for a hybrid capacitor obtained by the production method of the present invention is suitably used for a hybrid capacitor using an aprotic organic solvent forming an aprotic organic solvent electrolyte solution as an electrolyte solvent. Examples of the aprotic organic solvent include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone, acetonitrile, dimethoxyethane, tetrahydrofuran, dioxolane, methylene chloride, sulfolane and the like. Furthermore, a mixed solution in which two or more of these aprotic organic solvents are mixed can also be used.
　また、上記を単独または混合して用いる電解液溶媒に溶解させる電解質としては、リチウムイオンを生成しうる電解質であれば、あらゆるものを用いることができる。このような電解質としては、例えばＬｉＣｌＯ４、ＬｉＡｓＦ６、ＬｉＢＦ４、ＬｉＰＦ６、ＬｉＮ（Ｃ２Ｆ５ＳＯ２）２、ＬｉＮ（ＣＦ３ＳＯ２）２等が挙げられる。なお、上記の電解質及び電解液溶媒は、充分に脱水された状態で混合され、電解質溶液とするが、電解液中の電解質の濃度は、電解液による内部抵抗を小さくするため少なくとも０．１モル／リットル以上とすることが好ましく、０．５～１．５モル／リットルの範囲が更に好ましい。 Also, any electrolyte can be used as long as it is an electrolyte capable of generating lithium ions as the electrolyte dissolved in the electrolyte solution solvent used alone or in combination. Examples of such an electrolyte include LiClO4, LiAsF6, LiBF4, LiPF6, LiN (C2F5SO2) 2, LiN (CF3SO2) 2, and the like. The electrolyte and the electrolyte solvent are mixed in a sufficiently dehydrated state to obtain an electrolyte solution. The electrolyte concentration in the electrolyte is at least 0.1 mol in order to reduce the internal resistance of the electrolyte. / Liter or more is preferable, and the range of 0.5 to 1.5 mol / liter is more preferable.
　また、ハイブリッドキャパシタでは、帯状の正極と負極とをセパレータを介して捲回させる捲回型、あるいは板状の正極と負極とをセパレータを介して積層した積層型とされる。用いられるセパレータとしては、一般に厚みが２５μｍ～１００μｍ、気孔率３０％～８０％程度のポリプロピレンもしくはポリエチレン製の微多孔膜を用いることができる。厚みが２５μmよりも薄くなるとミクロショートの原因になったり、あるいは電解液の保液量が少なくなりセルの特性が悪化する。一方、１００μｍよりも厚くなるとセルの内部抵抗が大きくなる。また気孔率に関しては３０％よりも小さくなるとイオン拡散抵抗が大きくなり、セルの抵抗が大きくなる。８０％よりも大きくなると抵抗を小さくする上では好ましいが、正極と負極の短絡の原因となる。ここで、セパレータの気孔率は、｛１－（セパレータ重量／セパレータ素材密度）／（セパレータ見かけ体積）｝の比を百分率に換算して得られる。 Also, the hybrid capacitor is a winding type in which a strip-like positive electrode and a negative electrode are wound through a separator, or a laminated type in which a plate-like positive electrode and a negative electrode are laminated through a separator. As the separator to be used, a microporous film made of polypropylene or polyethylene having a thickness of 25 μm to 100 μm and a porosity of about 30% to 80% can be generally used. If the thickness is less than 25 μm, it may cause micro-shorts, or the amount of electrolyte solution retained will decrease and the cell characteristics will deteriorate. On the other hand, if the thickness exceeds 100 μm, the internal resistance of the cell increases. When the porosity is less than 30%, the ion diffusion resistance increases, and the resistance of the cell increases. If it exceeds 80%, it is preferable for reducing the resistance, but it causes a short circuit between the positive electrode and the negative electrode. Here, the porosity of the separator can be obtained by converting the ratio of {1- (separator weight / separator material density) / (separator apparent volume)} into a percentage.
　ハイブリッドキャパシタにおいて、リチウムイオンを吸蔵、脱離しうる負極をリチウム金属と接触させて、予め化学的方法又は電気化学的方法でリチウムイオンを吸蔵、担持（以下、ドーピングともいう）させて負極電位を下げることにより、耐電圧を高くしエネルギー密度を大幅に大きくすることができる。本発明の製造方法で得られるハイブリッドキャパシタ用電極を具えるハイブリッドキャパシタは、多孔化集電体を使用しているので、貫通孔を通じてリチウムイオンが移動可能であり、セルの端部にリチウム金属を配置するだけで、セル中の全負極にリチウムイオンをスムーズに且つ均一にドーピングすることができる。 In a hybrid capacitor, a negative electrode capable of inserting and extracting lithium ions is brought into contact with lithium metal, and lithium ions are inserted and stored (hereinafter also referred to as doping) by a chemical method or an electrochemical method in advance to lower the negative electrode potential. As a result, the withstand voltage can be increased and the energy density can be greatly increased. Since the hybrid capacitor including the electrode for a hybrid capacitor obtained by the manufacturing method of the present invention uses a porous current collector, lithium ions can move through the through-hole, and lithium metal is placed at the end of the cell. By simply disposing, all the negative electrodes in the cell can be smoothly and uniformly doped with lithium ions.
　リチウムイオンのドーピングは、負極と正極の片方あるいは両方いずれでもよいが、例えば正極に活性炭を用いた場合、リチウムイオンのドーピング量が多くなり正極電位が低くなると、リチウムイオンを不可逆的に消費してしまい、セルの容量が低下する等の不具合が生じる場合がある。このため、負極と正極にドーピングするリチウムイオンは、それぞれの電極活物質を考慮し、これらの不具合を生じないようにするのが好ましい。正極のドーピング量と負極のドーピング量を制御することは工程上煩雑となるため、リチウムイオンのドーピングは好ましくは負極に対して行われる。 Lithium ion doping may be one or both of the negative electrode and the positive electrode. For example, when activated carbon is used for the positive electrode, the lithium ion is irreversibly consumed when the amount of lithium ion doping increases and the positive electrode potential decreases. In other words, a problem such as a decrease in cell capacity may occur. For this reason, it is preferable that the lithium ions doped in the negative electrode and the positive electrode do not cause these problems in consideration of the respective electrode active materials. Since controlling the doping amount of the positive electrode and the doping amount of the negative electrode is complicated in the process, the doping of lithium ions is preferably performed on the negative electrode.
　以下、実施例および比較例により本発明をさらに具体的に説明する。なお、実施例および比較例における部および％は、特に断りのない限り重量基準である。 Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In the examples and comparative examples, “part” and “%” are based on weight unless otherwise specified.
　実施例および比較例における各特性は、下記の方法に従い測定する。 Each characteristic in Examples and Comparative Examples is measured according to the following method.
（複合粒子の表面平均空隙率）
　下記実施例、比較例において製造した複合粒子の表面平均空隙率を以下の方法で求める。
まず、倍率２０００倍で複合粒子の電子顕微鏡写真を測定し、任意の粒子について、視野２０μｍ２の範囲で白黒２５６階調の画像データとして画像解析ソフト（ａｎａｌｙＳＩＳ：Ｓｏｆｔ　Ｉｍａｇｉｎｇ　Ｓｙｓｔｅｍ社製）に読み込み、その画像の最明部が２５５、最暗部が０となるようにコントラストの最適化を行う。次いで、しきい値を７７に設定して２値化処理を行い、得られた２値化画像より複合粒子表面における０．１μｍ２以上の面積を有する空隙の割合を求める。同一粒子について、任意の異なる視野において全５回同様の測定を行い、さらに、同じ測定を１０個の粒子について行い、平均化したものを複合粒子の表面平均空隙率とする。 (Surface average porosity of composite particles)
The average surface porosity of the composite particles produced in the following examples and comparative examples is determined by the following method.
First, an electron micrograph of the composite particles was measured at a magnification of 2000 times, and arbitrary particles were read into image analysis software (analySIS: Soft Imaging System) as black and white 256-gradation image data within a field of view of 20 μm. The contrast is optimized so that the brightest part of the image is 255 and the darkest part is zero. Next, the threshold value is set to 77, binarization processing is performed, and the ratio of voids having an area of 0.1 μm 2 or more on the composite particle surface is obtained from the obtained binarized image. For the same particle, the same measurement is performed 5 times in any different field of view, and the same measurement is performed for 10 particles, and the average is the surface average porosity of the composite particles.
（電極層厚さの測定）
　電極層厚さは集電体の両面に電極層を形成した後に、渦電流式変位センサ（センサヘッド部ＥＸ－１１０Ｖ、アンプユニット部ＥＸ－Ｖ０２：キーエンス社製）を用いて測定する。長手方向に１０ｃｍ間隔、幅方向に２ｃｍ間隔で各電極層の厚さを測定し、それらの平均値を電極層の厚さとする。 (Measurement of electrode layer thickness)
The electrode layer thickness is measured using an eddy current displacement sensor (sensor head unit EX-110V, amplifier unit unit EX-V02: manufactured by Keyence Corporation) after forming electrode layers on both sides of the current collector. The thickness of each electrode layer is measured at intervals of 10 cm in the longitudinal direction and at intervals of 2 cm in the width direction, and the average value thereof is taken as the thickness of the electrode layer.
（内部抵抗の測定）
　実施例および比較例で製造したハイブリッドキャパシタ用電極を用いて積層型ラミネートセルのハイブリッドキャパシタを作製し、容量と内部抵抗は、２４時間静置させた後に充放電の操作を行い測定する。ここで、充電は２Ａの定電流で開始し、電圧が３．６Ｖに達したらその電圧を１時間保って定電圧充電とする。また、放電は充電終了直後に定電流０．９Ａで１．９Ｖに達するまで行う。容量は放電時のエネルギー量から電極活物質の重量あたりの容量として算出する。内部抵抗は放電直後の電圧降下から算出する。 (Measurement of internal resistance)
A hybrid capacitor of a laminated laminate cell is manufactured using the hybrid capacitor electrode manufactured in the examples and comparative examples, and the capacity and internal resistance are measured by performing charge / discharge operation after being allowed to stand for 24 hours. Here, charging starts with a constant current of 2 A, and when the voltage reaches 3.6 V, the voltage is maintained for 1 hour to be constant voltage charging. Discharging is performed immediately after the end of charging until it reaches 1.9 V at a constant current of 0.9 A. The capacity is calculated as the capacity per weight of the electrode active material from the energy amount at the time of discharge. The internal resistance is calculated from the voltage drop immediately after discharge.
実施例１
（正極電極層形成に使用する複合粒子の作製）
　電極活物質（比表面積２，０００ｍ２／ｇ及び重量平均粒子径５μｍの活性炭）１００部、導電材（アセチレンブラック「デンカブラック粉状」：電気化学工業（株）製）５部、分散型結着剤（数平均粒子径０．１５μｍ、ガラス転移温度－４０℃の架橋型アクリレート系重合体の４０％水分散体「ＡＤ２１１」：日本ゼオン（株）製）を固形分相当で７．５部、溶解型樹脂（カルボキシメチルセルロースの１．５％水溶液「ＤＮ－８００Ｈ」、カルボキシメチルセルロースの重量平均分子量３０万未満：ダイセル化学工業（株）製）を固形分相当で１．４部、及びイオン交換水を「Ｔ．Ｋ．ホモミクサー」（特殊機化工業（株）製）で攪拌混合して、固形分濃度２５％のスラリーを得る。次いで、このスラリーをスプレー乾燥機を用いて１５０℃の熱風で噴霧乾燥し、体積平均粒子径５０μｍ、表面平均空隙率１３％の球状の複合粒子として電極材料を得る。この複合粒子の体積平均粒径は、粒度分布測定装置（ＳＡＬＤ－３１００：島津製作所（株）製）を用いて測定する。なお、実施例１～７のハイブリッドキャパシタの正極電極層形成では、上記で作製した複合粒子を用いる。 Example 1
(Preparation of composite particles used for positive electrode layer formation)
100 parts of electrode active material (activated carbon with a specific surface area of 2,000 m2 / g and a weight average particle diameter of 5 μm), 5 parts of conductive material (acetylene black “Denka black powder”: manufactured by Denki Kagaku Kogyo Co., Ltd.), dispersive binding 7.5 parts of an agent (a cross-linked acrylate polymer having a number average particle diameter of 0.15 μm and a glass transition temperature of −40 ° C., 40% aqueous dispersion “AD211” manufactured by Nippon Zeon Co., Ltd.) Dissolved resin (1.5% aqueous solution of carboxymethyl cellulose “DN-800H”, weight average molecular weight of carboxymethyl cellulose less than 300,000: manufactured by Daicel Chemical Industries, Ltd.) 1.4 parts in solids equivalent, and ion-exchanged water Is stirred and mixed with “TK homomixer” (manufactured by Tokushu Kika Kogyo Co., Ltd.) to obtain a slurry having a solid content concentration of 25%. Next, this slurry is spray-dried with hot air at 150 ° C. using a spray dryer to obtain an electrode material as spherical composite particles having a volume average particle diameter of 50 μm and a surface average porosity of 13%. The volume average particle size of the composite particles is measured using a particle size distribution measuring device (SALD-3100: manufactured by Shimadzu Corporation). In the formation of the positive electrode layer of the hybrid capacitors of Examples 1 to 7, the composite particles prepared above are used.
（負極電極層形成に使用する複合粒子の作製）
　厚さ０．５ｍｍのフェノール樹脂成形板をシリコニット電気炉中に入れ、窒素雰囲気下で５００℃まで５０℃／時間の速度で、更に１０℃／時間の速度で６６０℃まで昇温して熱処理し、ポリアセンを合成する。かくして得られるポリアセン板をディスクミルで粉砕し、篩にかけて平均粒子径５μｍのＰＡＳ粉体を得る。このポリアセン粉体のＨ／Ｃ比は０．２１である。得られるポリアセン１００部、分散型結着剤（数平均粒子径０．１５μｍ、ガラス転移温度－４０℃の架橋型アクリレート系重合体の４０％水分散体「ＡＤ２１１」：日本ゼオン（株）製）を固形分相当で７．５部、溶解型樹脂（カルボキシメチルセルロースの１．５％水溶液「ＤＮ－８００Ｈ」、カルボキシメチルセルロースの重量平均分子量３０万未満：ダイセル化学工業（株）製）を固形分相当で１．４部、及びイオン交換水を加えて、「Ｔ．Ｋ．ホモミクサー」（特殊機化工業（株）製）で攪拌混合して、固形分濃度２５％のスラリーを得る。次いで、スラリーをスプレー乾燥機を用いて１５０℃の熱風で噴霧乾燥し、体積平均粒子径５０μｍ、表面平均空隙率１３％の球状の複合粒子として電極材料を得る。この複合粒子の体積平均粒径は、粒度分布測定装置（ＳＡＬＤ－３１００：島津製作所（株）製）を用いて測定する。なお、ハイブリッドキャパシタの負極電極層形成の実施例では、すべて上記で作製した複合粒子を用いる。 (Preparation of composite particles used for negative electrode layer formation)
A 0.5 mm thick phenolic resin molded plate is placed in a siliconite electric furnace and heated to a temperature of 50 ° C./hour up to 500 ° C. and further to 660 ° C. at a rate of 10 ° C./hour in a nitrogen atmosphere. Synthesize polyacene. The polyacene plate thus obtained is pulverized by a disk mill and sieved to obtain a PAS powder having an average particle diameter of 5 μm. The polyacene powder has an H / C ratio of 0.21. 100 parts of polyacene obtained, dispersion-type binder (40% aqueous dispersion “AD211” of a cross-linked acrylate polymer having a number average particle size of 0.15 μm and a glass transition temperature of −40 ° C .: manufactured by Nippon Zeon Co., Ltd.) 7.5 parts in terms of solid content, dissolved resin (1.5% aqueous solution of carboxymethyl cellulose “DN-800H”, weight average molecular weight of carboxymethyl cellulose less than 300,000: manufactured by Daicel Chemical Industries, Ltd.) Then, 1.4 parts and ion-exchanged water are added, and the mixture is stirred and mixed with “TK homomixer” (manufactured by Tokushu Kika Kogyo Co., Ltd.) to obtain a slurry with a solid content concentration of 25%. Next, the slurry is spray-dried with hot air at 150 ° C. using a spray dryer to obtain an electrode material as spherical composite particles having a volume average particle diameter of 50 μm and a surface average porosity of 13%. The volume average particle size of the composite particles is measured using a particle size distribution measuring device (SALD-3100: manufactured by Shimadzu Corporation). In the examples of forming the negative electrode layer of the hybrid capacitor, all the composite particles prepared above are used.
（ハイブリッドキャパシタ用電極シートの作製）
　得られる正極用の複合粒子を、集電体として用いる厚さ３５μｍ、開口率（開口面積）５０％、開口径１ｍｍのアルミニウム製エキスパンドメタル（日本金属工業株式会社製）とともに、図１に示すようなロールプレス機（加圧装置）を用いて電極を作製する。ここで使われるエキスパンドメタルには、塗料として固形分濃度１５％のカーボン系の導電性塗料（日本黒鉛工業株式会社製、バニーハイトＴ－７０２Ａ）を用い、ダイとロールバーの隙間を２００μｍ、ダイリップの隙間を１５０μｍとして、塗料を吐出して両面塗工したものを用いる。図１に示すように、集電体１として用いるエキスパンドメタルを成形用ロール（プレスロール）２．２間に供給し、粉体供給装置３，３を用いて複合粒子４，４をそれぞれ成形用ロール２，２（ロール温度１２０℃、プレス線圧４ｋＮ／ｃｍ）に供給して、成形速度５ｍ／分で加圧成形して、正極用の電極シートを得る。また、複合粒子として負極用の複合粒子を用いる以外は、上記と同様にして負極用の電極シートを得る。なお、実施例１～８における（一対のロールのロール間隙）／（多孔化集電体厚み＋電極材料層の厚さ）の値は、すべて０．５となるように一対のロールのロール間隙や電極材料層の厚さを調整する。 (Preparation of electrode sheet for hybrid capacitor)
As shown in FIG. 1, together with the aluminum expanded metal (manufactured by Nippon Metal Industry Co., Ltd.) having a thickness of 35 μm, an aperture ratio (opening area) of 50%, and an opening diameter of 1 mm, the obtained composite particles for positive electrode are used. An electrode is produced using a simple roll press machine (pressure device). For the expanded metal used here, a carbon-based conductive paint with a solid content of 15% (Nihon Graphite Industries Co., Ltd., Bunny Height T-702A) is used as the paint, and the gap between the die and the roll bar is 200 μm. The gap is set to 150 μm, and a paint is applied on both sides by discharging the paint. As shown in FIG. 1, expanded metal used as a current collector 1 is supplied between forming rolls (press rolls) 2.2, and composite particles 4 and 4 are respectively formed using powder supply devices 3 and 3. Rolls 2 and 2 (roll temperature: 120 ° C., press linear pressure: 4 kN / cm) are subjected to pressure molding at a molding speed of 5 m / min to obtain an electrode sheet for a positive electrode. Moreover, the electrode sheet for negative electrodes is obtained like the above except using the composite particles for negative electrodes as composite particles. In Examples 1 to 8, the roll gap between the pair of rolls is such that the values of (roll gap between the pair of rolls) / (thickness of the porous current collector + thickness of the electrode material layer) are all 0.5. And adjust the thickness of the electrode material layer.
（測定用セルの作製）
　上記の電極シートを、電極層が形成されていない集電体シート部を縦２ｃｍ×横２ｃｍを残し、電極層が形成されている部分を縦５ｃｍ×横５ｃｍになるように切り抜く。これに縦７ｃｍ×横１ｃｍ×厚み０．０１ｃｍのアルミからなるタブ材を未塗工部に超音波溶接して測定用電極を作製する。測定用電極は、正極１０組、負極１１組を用意し、１６０℃で４０分間乾燥する。セパレータとして厚さ３５μｍのセルロース／レーヨン混合不織布を用いて、正極集電体、負極集電体の端子溶接部がそれぞれ反対側になるよう配置し、正極、負極の対向面が２０層になるように、また積層した電極の最外部の電極が負極となるように積層する。最上部と最下部はセパレータを配置させて４辺をテープ留めし、正極集電体の端子溶接部（１０枚）、負極集電体の端子溶接部（１１枚）をそれぞれ超音波溶接する。 (Preparation of measurement cell)
The above-mentioned electrode sheet is cut out so that the collector sheet portion on which the electrode layer is not formed is 2 cm long × 2 cm wide and the portion on which the electrode layer is formed is 5 cm long × 5 cm wide. A tab material made of aluminum having a length of 7 cm, a width of 1 cm, and a thickness of 0.01 cm is ultrasonically welded to the uncoated portion to produce a measurement electrode. As the measurement electrodes, 10 sets of positive electrodes and 11 sets of negative electrodes are prepared and dried at 160 ° C. for 40 minutes. Using a cellulose / rayon mixed nonwoven fabric having a thickness of 35 μm as a separator, the terminal welds of the positive electrode current collector and the negative electrode current collector are arranged on opposite sides, and the opposing surfaces of the positive electrode and the negative electrode are 20 layers. In addition, lamination is performed so that the outermost electrode of the laminated electrodes becomes a negative electrode. The uppermost part and the lowermost part are provided with separators, and four sides are taped, and the terminal welded part (10 sheets) of the positive electrode current collector and the terminal welded part (11 sheets) of the negative electrode current collector are ultrasonically welded.
　リチウム極として、リチウム金属箔（厚み８２μｍ、縦５ｃｍ×横５ｃｍ）を厚さ８０μｍのステンレス網に圧着したものを用い、該リチウム極を最外部の負極と完全に対向するように積層した電極の上部および下部に各１枚配置する。尚、リチウム極集電体の端子溶接部（２枚）は負極端子溶接部に抵抗溶接する。 As a lithium electrode, a lithium metal foil (thickness 82 μm, length 5 cm × width 5 cm) bonded to an 80 μm-thick stainless steel mesh is used, and the lithium electrode is laminated so as to completely face the outermost negative electrode One sheet is placed at the top and one at the bottom. The terminal welding part (two sheets) of the lithium electrode current collector is resistance-welded to the negative electrode terminal welding part.
　上記リチウム箔を最上部と最下部に配置した積層体を深絞り下外装フィルムの内部へ設置し、外装ラミネートフィルムで覆い三辺を融着後、電解液としてエチレンカーボネート、ジエチルカーボネートおよびプロピレンカーボネートを重量比で３：４：１とした混合溶媒に、１モル／リットルの濃度にＬｉＰＦ6を溶解した溶液を真空含浸させた後、残り一辺を融着させ、フィルム型キャパシタを作製する。得られるフィルム型キャパシタについて各特性を測定する。結果を表１に示す。 Laminate with the lithium foil placed at the top and bottom is placed inside the deep-drawn lower exterior film, covered with the exterior laminate film and fused on the three sides, and then ethylene carbonate, diethyl carbonate and propylene carbonate are used as the electrolyte. A solution obtained by dissolving LiPF6 at a concentration of 1 mol / liter is vacuum impregnated in a mixed solvent with a weight ratio of 3: 4: 1, and the remaining side is then fused to produce a film type capacitor. Each characteristic is measured about the film type capacitor obtained. The results are shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
実施例２
　成形速度を１５ｍ／分にする以外は実施例１と同様にして電極シートおよびフィルム型キャパシタを作製する。結果を表１に示す。 Example 2
An electrode sheet and a film type capacitor are produced in the same manner as in Example 1 except that the molding speed is 15 m / min. The results are shown in Table 1.
実施例３
　多孔化集電体として、厚さが３０μｍ、開口面積が３７面積％、開口径が０．１μｍのパンチングメタルを用いる以外は実施例１と同様にして電極シートおよびフィルム型キャパシタを作製する。結果を表１に示す。 Example 3
An electrode sheet and a film type capacitor are produced in the same manner as in Example 1 except that a punching metal having a thickness of 30 μm, an opening area of 37 area%, and an opening diameter of 0.1 μm is used as the porous collector. The results are shown in Table 1.
実施例４
　成形速度を１５ｍ／分にする以外は実施例３と同様にして電極シートおよびフィルム型キャパシタを作製する。結果を表１に示す。 Example 4
An electrode sheet and a film type capacitor are produced in the same manner as in Example 3 except that the molding speed is 15 m / min. The results are shown in Table 1.
実施例５
　成形速度を４０ｍ／分にする以外は実施例３と同様にして電極シートおよびフィルム型キャパシタを作製する。結果を表１に示す。 Example 5
An electrode sheet and a film type capacitor are produced in the same manner as in Example 3 except that the molding speed is 40 m / min. The results are shown in Table 1.
実施例６
　多孔化集電体として、厚さが３０μｍ、開口面積が６０面積％、開口径が０．１μｍのパンチングメタルを用いる以外は実施例５と同様にして電極シートおよびフィルム型キャパシタを得る。結果を表１に示す。 Example 6
An electrode sheet and a film type capacitor are obtained in the same manner as in Example 5 except that a punching metal having a thickness of 30 μm, an opening area of 60 area%, and an opening diameter of 0.1 μm is used as the porous current collector. The results are shown in Table 1.
実施例７
　多孔化集電体として、厚さが３０μｍ、開口面積が６０面積％、開口径３μｍのパンチングメタルを用いる以外は実施例５と同様にして電極シートおよびフィルム型キャパシタを得る。結果を表１に示す。 Example 7
An electrode sheet and a film type capacitor are obtained in the same manner as in Example 5 except that a punching metal having a thickness of 30 μm, an opening area of 60 area%, and an opening diameter of 3 μm is used as the porous current collector. The results are shown in Table 1.
実施例８
　正極電極層形成に使用する複合粒子の作製において、溶解型樹脂を、他の溶解型樹脂（カルボキシメチルセルロースの１％水溶液「ＢＳＨ－１２」：カルボキシメチルセルロースの重量平均分子量３３万～３８万、第一工業化学（株）製）に変える以外は実施例７と同様にして電極シートおよびフィルム型キャパシタを得る。結果を表１に示す。なお、正極電極層形成に使用する複合粒子の体積平均粒子径は５０μｍ、表面平均空隙率は２２％である。 Example 8
In the preparation of composite particles used for forming the positive electrode layer, the soluble resin was replaced with another soluble resin (1% aqueous solution of carboxymethyl cellulose “BSH-12”: weight average molecular weight of carboxymethyl cellulose 330,000 to 380,000, first An electrode sheet and a film type capacitor are obtained in the same manner as in Example 7 except that the material is changed to Kogyo Kagaku Co. The results are shown in Table 1. The volume average particle diameter of the composite particles used for forming the positive electrode layer is 50 μm, and the surface average porosity is 22%.
比較例１
（正極電極層形成に使用する塗料の作製）
　ヤシ殻を原料とし、これを電気炉中に入れ窒素気流下で５０℃／時間の速度で９５０℃まで昇温した後、窒素／水蒸気１：１の混合ガスにより２時間賦活することにより、比表面積１，８６０ｍ２／ｇの活性炭を製造する。該活性炭をボールミル粉砕機で粉砕して平均粒子径が５μｍの活性炭粉末を得る。 Comparative Example 1
(Preparation of paint used for positive electrode layer formation)
By using coconut shell as a raw material, placing it in an electric furnace, raising the temperature to 950 ° C. at a rate of 50 ° C./hour under a nitrogen stream, and then activating it with a mixed gas of nitrogen / steam 1: 1 for 2 hours, An activated carbon having a surface area of 1,860 m 2 / g is produced. The activated carbon is pulverized by a ball mill pulverizer to obtain activated carbon powder having an average particle size of 5 μm.
　上記活性炭粉末９２部、アセチレンブラック粉体４部、スチレン－ブタジエンゴム（ＳＢＲ）４部、カルボキシメチルセルロース１部を混合し、ここにイオン交換水を加えて固形分が３５％となる組成にて充分混合することにより正極塗料を得る。 Mixing 92 parts of the above activated carbon powder, 4 parts of acetylene black powder, 4 parts of styrene-butadiene rubber (SBR) and 1 part of carboxymethylcellulose, and adding ion-exchanged water to the composition, the solid content is 35%. A positive electrode paint is obtained by mixing.
（正極の製造方法）
　多孔化集電体として厚さ３５μｍ（開口率５０％、開口径１ｍｍ）のアルミニウム製エキスパンドメタル（日本金属工業株式会社製）、塗料として固形分濃度１５％のカーボン系の導電性塗料（日本黒鉛工業株式会社製、バニーハイトＴ－７０２Ａ）を用い、ダイとロールバーの隙間を２００μｍ、ダイリップの隙間を１５０μｍとして、塗料を吐出させて両面塗工を実施する。ただし、塗工される集電体が乾燥炉に入る手前で集電体に対し垂直方向からエアを吹き付けることにより、エキスパンドメタルの貫通孔内に保持された塗料を吹き飛ばし、エキスパンドメタルの金属部に導電性塗料がコーティングされた下塗り集電体を得る。 (Production method of positive electrode)
Aluminum expanded metal (manufactured by Nippon Metal Industry Co., Ltd.) with a thickness of 35 μm (opening ratio 50%, opening diameter 1 mm) as a porous collector, and carbon-based conductive paint (Nippon Graphite) with a solid content concentration of 15%. Using a bunny height T-702A manufactured by Kogyo Co., Ltd., the gap between the die and the roll bar is set to 200 μm, and the gap between the die lip is set to 150 μm. However, before the current collector to be coated enters the drying furnace, air is blown from the vertical direction to the current collector, so that the paint held in the through hole of the expanded metal is blown off, and the metal part of the expanded metal is blown. An undercoat current collector coated with a conductive paint is obtained.
　該下塗り集電体と上記で得られる正極塗料を用いて、ダイとロールバーの隙間を３００μｍ、ダイリップの隙間を１５０μｍとして、正極塗料を吐出させて両面塗工を行い、正極を得る。巻取りのテンションは５Ｎとし、エキスパンドメタルの送り速度（塗工速度）を０．５ｍ／分とする。乾燥炉内の温度は７０℃に設定する。 Using the undercoat current collector and the positive electrode paint obtained above, the gap between the die and the roll bar is 300 μm, the gap between the die lip is 150 μm, and the positive electrode paint is discharged to perform double-side coating to obtain a positive electrode. The winding tension is 5 N, and the expanded metal feed speed (coating speed) is 0.5 m / min. The temperature in the drying furnace is set to 70 ° C.
（負極電極層形成に使用する塗料の作製）
　厚さ０．５ｍｍのフェノール樹脂成形板をシリコニット電気炉中に入れ、窒素雰囲気下で５００℃まで５０℃／時間の速度で、更に１０℃／時間の速度で６５０℃まで昇温し、熱処理し、ポリアセン（ＰＡＳ）板を合成する。かくして得られるＰＡＳ板をボールミルで粉砕することにより、体積平均粒子径が７μｍのＰＡＳ粉体を得る。 (Preparation of paint used for negative electrode layer formation)
A 0.5 mm thick phenolic resin molded plate is placed in a siliconite electric furnace, heated to 500 ° C. at a rate of 50 ° C./hour, and further at a rate of 10 ° C./hour to 650 ° C. in a nitrogen atmosphere, followed by heat treatment. A polyacene (PAS) plate is synthesized. The PAS plate thus obtained is pulverized with a ball mill to obtain a PAS powder having a volume average particle diameter of 7 μm.
　次に、上記ＰＡＳ粉体９２部、アセチレンブラック粉体４部、スチレン－ブタジエンゴム（ＳＢＲ）４部、カルボキシメチルセルロース３．２部を混合し、ここにイオン交換水を添加して固形分濃度が５０％となる組成にて充分混合することにより負極塗料を得る。 Next, 92 parts of the above PAS powder, 4 parts of acetylene black powder, 4 parts of styrene-butadiene rubber (SBR), and 3.2 parts of carboxymethylcellulose are mixed, and ion exchange water is added thereto to obtain a solid content concentration. A negative electrode paint is obtained by sufficiently mixing at a composition of 50%.
（負極の製造方法）
　多孔化集電体として厚さ３２μｍ（開口率５０％、開口径１ｍｍ）の銅製エキスパンドメタル（日本金属工業株式会社製）を原反フープ設置ロールに固定し、該エキスパンドメタルをガイドロールを経由してダイとロールバーの間を通し、２ｍの乾燥炉内を通して巻取り部に固定する。巻取りのテンションは５Ｎとし、エキスパンドメタルの送り速度を０．５ｍ／分とする。乾燥炉内の温度は７０℃に設定する。 (Method for producing negative electrode)
A copper expanded metal (manufactured by Nippon Metal Industry Co., Ltd.) having a thickness of 32 μm (opening ratio 50%, opening diameter 1 mm) as a porous current collector is fixed to a raw fabric hoop installation roll, and the expanded metal is passed through a guide roll. Then, it passes between the die and the roll bar, and is fixed to the winding part through a 2 m drying furnace. The winding tension is 5 N, and the expanded metal feed rate is 0.5 m / min. The temperature in the drying furnace is set to 70 ° C.
　該集電体と上記で得られる負極塗料を用いる他は、正極と同様に両面塗工することで負極を得る。 The negative electrode is obtained by coating on both sides in the same manner as the positive electrode except that the current collector and the negative electrode paint obtained above are used.
　こうして得られる正極および負極を用いる以外は、実施例１と同様にしてフィルム型キャパシタを作製する。結果を表１に示す。 A film type capacitor is produced in the same manner as in Example 1 except that the positive electrode and the negative electrode thus obtained are used. The results are shown in Table 1.
比較例２
　エキスパンドメタルの送り速度（塗工速度）を５ｍ／分にする以外は比較例１と同様にして電極シートおよびフィルム型キャパシタを得る。結果を表１に示す。エキスパンドメタル上の塗料塗工面には、塗料が塗工されていない部分（未塗工部）がみられる。そのため、電極層の厚さにばらつき（５～６０μｍ）がみられる。 Comparative Example 2
An electrode sheet and a film type capacitor are obtained in the same manner as in Comparative Example 1 except that the expanded metal feed rate (coating rate) is 5 m / min. The results are shown in Table 1. On the paint coated surface on the expanded metal, there is a portion where no paint is applied (uncoated portion). Therefore, variation (5 to 60 μm) is observed in the thickness of the electrode layer.
比較例３
　エキスパンドメタルの送り速度（塗工速度）を１５ｍ／分にする以外は比較例１と同様にして電極シートの製造を行うと、集電体であるエキスパンドメタルが破断し、電極シートの作成ができない。結果を表１に示す。 Comparative Example 3
If an electrode sheet is produced in the same manner as in Comparative Example 1 except that the expanded metal feed rate (coating speed) is 15 m / min, the expanded metal that is the current collector is broken and the electrode sheet cannot be produced. . The results are shown in Table 1.
比較例４
　多孔化集電体として、厚さ３０μｍ、開口面積が６０面積％、開口径が３μｍのパンチングメタルを用いる以外は比較例１と同様にして電極シートおよびフィルム型キャパシタを得る。結果を表１に示す。 Comparative Example 4
An electrode sheet and a film type capacitor are obtained in the same manner as in Comparative Example 1 except that a punching metal having a thickness of 30 μm, an opening area of 60 area%, and an opening diameter of 3 μm is used as the porous collector. The results are shown in Table 1.
比較例５
　パンチングメタルの送り速度（塗工速度）を５ｍ／分にする以外は比較例４と同様にして電極シートおよびフィルム型キャパシタを得る。結果を表１に示す。エキスパンドメタル上の塗工面には、塗料が塗工されていない部分（未塗工部）がみられる。そのため、電極層の厚さにばらつき（５～６０μｍ）がみられる。 Comparative Example 5
An electrode sheet and a film type capacitor are obtained in the same manner as in Comparative Example 4 except that the feed rate (coating speed) of the punching metal is 5 m / min. The results are shown in Table 1. On the coated surface on the expanded metal, a portion where no paint is applied (uncoated portion) is seen. Therefore, variation (5 to 60 μm) is observed in the thickness of the electrode layer.
比較例６
　パンチングメタルの送り速度（塗工速度）を１５ｍ／分にする以外は比較例４と同様にして電極シートの製造を行うと、集電体であるエキスパンドメタルが破断し、電極シートの作成ができない。結果を表１に示す。 Comparative Example 6
When the electrode sheet is manufactured in the same manner as in Comparative Example 4 except that the feed rate (coating speed) of the punching metal is 15 m / min, the expanded metal as the current collector is broken and the electrode sheet cannot be created. . The results are shown in Table 1.
　比較例の湿式塗布型による製造方法では、成形速度を上げると未塗工部が発生して均一な電極が得られなかったり、集電体の破断が起きて成形自体が不可能になる。一方、実施例の乾式成形による製造法では、比較例のような問題は起きず、低速度で成形すると安定して電極厚さが大きい電極が得られる。また高速での成形では安定して薄膜電極が得られ、低抵抗化が可能である。 In the manufacturing method using the wet coating type of the comparative example, when the molding speed is increased, an uncoated part is generated and a uniform electrode cannot be obtained, or the current collector is broken and the molding itself becomes impossible. On the other hand, in the manufacturing method by dry molding of the example, the problem as in the comparative example does not occur, and an electrode having a large electrode thickness can be stably obtained by molding at a low speed. In addition, thin film electrodes can be obtained stably by high-speed molding, and the resistance can be reduced.
　なお、以上説明した実施形態及び実施例は、本発明の理解を容易にするために記載されたものであって、本発明を限定するために記載されたものではない。従って、上記の実施形態又は実施例に開示された各要素は、本発明の技術的範囲に属する全ての設計変更や均等物をも含む趣旨である。 The embodiments and examples described above are described for facilitating understanding of the present invention, and are not described for limiting the present invention. Accordingly, each element disclosed in the above embodiment or example is intended to include all design changes and equivalents belonging to the technical scope of the present invention.
　本発明は、２００８年３月２５日に提出された日本国特許出願第２００８－７９２７６号に含まれた主題に関連し、その開示のすべては、ここに参照事項として明白に組み込まれる。 The present invention relates to the subject matter contained in Japanese Patent Application No. 2008-79276 filed on Mar. 25, 2008, the entire disclosure of which is expressly incorporated herein by reference.

Claims (9)

  1. 　多孔化集電体上の少なくとも一表面に電極材料を供給する工程、および前記多孔化集電体と前記電極材料とを加圧して多孔化集電体上に電極層を形成する工程を含むハイブリッドキャパシタ用電極の製造方法。 A hybrid including a step of supplying an electrode material to at least one surface on a porous current collector, and a step of pressurizing the porous current collector and the electrode material to form an electrode layer on the porous current collector A method for manufacturing a capacitor electrode.
  2. 　前記加圧を、一対のロールを備える加圧装置で行うようにした請求項１記載の製造方法。 The manufacturing method according to claim 1, wherein the pressurization is performed by a pressurization apparatus including a pair of rolls.
  3. 　前記電極層を形成する工程における成形速度が１０ｍ／分以上である請求項１記載の製造方法。 The manufacturing method according to claim 1, wherein a forming speed in the step of forming the electrode layer is 10 m / min or more.
  4. 　前記電極材料が、
    　電極活物質および結着剤を含有し、且つ該電極活物質が該結着剤によって結着されてなる複合粒子である請求項１記載の製造方法。     The electrode material is
    The production method according to claim 1, which is a composite particle containing an electrode active material and a binder, and the electrode active material is bound by the binder.
  5. 　前記複合粒子の表面平均空隙率が１５％以上である請求項４記載のハイブリッドキャパシタ用電極の製造方法。 The method for producing an electrode for a hybrid capacitor according to claim 4, wherein the composite particles have a surface average porosity of 15% or more.
  6. 　（前記一対のロールのロール間隙）／（前記多孔化集電体の厚さ＋前記電極材料層の厚さ）が０．０１～１である請求項２記載の製造方法。 3. The manufacturing method according to claim 2, wherein (the roll gap between the pair of rolls) / (thickness of the porous current collector + thickness of the electrode material layer) is 0.01 to 1.
  7. 　前記多孔化集電体の開口面積が１０～９０面積％である請求項１記載の製造方法。 The manufacturing method according to claim 1, wherein an opening area of the porous current collector is 10 to 90 area%.
  8. 　前記多孔化集電体の開口径が０．１～１０μｍである請求項１記載の製造方法。 The manufacturing method according to claim 1, wherein the aperture diameter of the porous current collector is 0.1 to 10 µm.
  9. 　請求項１～８のいずれかに記載の製造方法により得られるハイブリッドキャパシタ用電極を備えるハイブリッドキャパシタ。 A hybrid capacitor comprising a hybrid capacitor electrode obtained by the manufacturing method according to any one of claims 1 to 8.
PCT/JP2009/055767 2008-03-25 2009-03-24 Method for production of electrode for hybrid capacitor WO2009119553A1 (en)

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JP2011249517A (en) * 2010-05-26 2011-12-08 Aisin Seiki Co Ltd Negative electrode material for lithium ion capacitor, dope method thereof, and lithium ion capacitor
JP2011249507A (en) * 2010-05-26 2011-12-08 Aisin Seiki Co Ltd High performance capacitor and method of doping negative electrode material for high performance capacitor
JP2012122834A (en) * 2010-12-08 2012-06-28 Lasertec Corp Thickness measurement apparatus for battery electrode material and thickness measurement method thereof

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JP2007005457A (en) * 2005-06-22 2007-01-11 Seiko Epson Corp Sealing device of package and method of manufacturing electronic device
JP2007035770A (en) * 2005-07-25 2007-02-08 Tdk Corp Manufacturing method of electrode for electrochemical element and manufacturing method of electrochemical element
JP2007141897A (en) * 2005-11-14 2007-06-07 Fuji Heavy Ind Ltd Lithium ion capacitor

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JP2006269110A (en) * 2005-03-22 2006-10-05 Jfe Chemical Corp Metal-graphite composite particle, cathode material for lithium ion secondary battery, cathode, and the lithium ion secondary battery
JP2007005457A (en) * 2005-06-22 2007-01-11 Seiko Epson Corp Sealing device of package and method of manufacturing electronic device
JP2007035770A (en) * 2005-07-25 2007-02-08 Tdk Corp Manufacturing method of electrode for electrochemical element and manufacturing method of electrochemical element
JP2007141897A (en) * 2005-11-14 2007-06-07 Fuji Heavy Ind Ltd Lithium ion capacitor

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011249517A (en) * 2010-05-26 2011-12-08 Aisin Seiki Co Ltd Negative electrode material for lithium ion capacitor, dope method thereof, and lithium ion capacitor
JP2011249507A (en) * 2010-05-26 2011-12-08 Aisin Seiki Co Ltd High performance capacitor and method of doping negative electrode material for high performance capacitor
JP2012122834A (en) * 2010-12-08 2012-06-28 Lasertec Corp Thickness measurement apparatus for battery electrode material and thickness measurement method thereof

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