JP2011216505A - Method for manufacturing polarizable electrode and electrochemical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a polarizable electrode stably, having high coating efficiency.SOLUTION: In the method for manufacturing a polarizable electrode, an electrode material is charged and an electrode layer is formed on at least one surface of a grounded collector. The electrochemical element including the polarizable electrode obtained by the manufacturing method is disclosed.

Description

  The present invention relates to a method for producing a polarizable electrode and an electrochemical device comprising the same.

  A power storage element using a polarizable electrode typified by an electric double layer capacitor can be rapidly charged and discharged, and thus is used as a power source for memory backup of electronic equipment. Furthermore, in recent years, application as a large power source such as a distributed power source or a hybrid vehicle is expected due to environmental problems and resource problems of energy. However, in order to apply the electric double layer capacitor as a large-scale power source, it is desired to reduce the internal resistance in order to reduce the energy loss during large current discharge.

  In order to reduce the internal resistance, it is common to reduce the thickness of the electrode, and it is required to manufacture the thin film electrode with high productivity.

  On the other hand, as a method for producing an electrode, a method in which an electrode material containing an electrode active material and a binder is made into a slurry, applied and dried; a method in which the electrode material is kneaded and extended to a target thickness with a rolling roll A method of pressure forming the electrode material as it is or in the form of composite particles. Among these, the method of pressure-molding the electrode material is preferable in terms of productivity, and various methods for supplying the electrode material have been proposed.

  As a method for supplying the electrode material, there is a method in which the electrode material is charged and electrostatically attached. This method is excellent in productivity because the electrode material can be supplied thinly and evenly, and the electrode material that has not adhered can be recovered and reused.

For example, Patent Document 1 discloses a method of applying a powder having water repellency on a surface to a current collector by electrostatic powder coating. According to this method, it is said that a hydrogen storage alloy electrode having water repellency uniformly and sufficiently enhanced can be produced.
Patent Document 2 discloses a method for producing an electrode, wherein an active material layer made of an active material, a conductive material, and a binder is formed on the surface of a current collector by a powder coating method. ing. According to this method, it is said that an electrode that is easy to control, has good productivity, and has excellent load characteristics as compared with the wet method can be obtained.
Further, in Patent Document 3, an incombustible or flame-retardant electrolyte solution is applied to the surface of an electrode structure, and further, an electrode material is applied by electrostatic copying and heat-fixed, whereby the electrolyte solution becomes an electrode material and an electrode structure. An electrode manufacturing method is disclosed, which is characterized in that According to this method, a higher performance electrode can be provided.
Moreover, in patent document 4, the spreading | diffusion process which spreads electrode raw material powder on the conveyance path | route drive | worked in a horizontal direction, the collector supply process which supplies a collector in the shape of the spread | distributed electrode raw material powder, The said electrode There is disclosed a method for producing an electrode for an electrochemical device, comprising: a zone press-bonding step of continuously pressing raw material powder and a current collector to form an electrode. And the method of making it adhere by static electricity, such as an electrostatic spraying method, is illustrated as a method of supplying electrode raw material powder.
Moreover, in patent document 5, an electrode material is apply | coated to the electrode structure surface, and in the electrode manufacturing apparatus which manufactures the electrode formed, the electrostatic screen application | coating means which apply | coats to electrode material and an electrode structure surface, and forms an electrode An electrode manufacturing apparatus is disclosed. According to this apparatus, a higher performance electrode can be manufactured.
Furthermore, in Patent Document 6, a fuel cell electrode formed by adhering an electrostatically charged electrode catalyst powder to a polymer electrolyte membrane has a structure with an appropriate pore distribution, and gas diffusion is further improved. It is said that the battery performance will improve because it improves.
JP-A-9-213316 JP 2001-351616 A JP 2004-281152 A WO2005 / 117043 publication JP 2004-281221 A JP-A-11-288728

An issue of manufacturing a thin film electrode with high productivity is that it can be stably produced continuously. For such problems, the methods described in Patent Documents 1 to 4 have a problem that continuous and stable production cannot be achieved.
In addition, although there is a possibility of recovery and reuse, improvement of the coating efficiency when the electrode material is supplied electrostatically is also important in terms of productivity. With respect to such a problem, there is a problem in that the coating efficiency cannot be sufficiently increased when the methods as in Patent Documents 5 and 6 are used.
Accordingly, an object of the present invention is to provide a method for stably producing a polarizable electrode with high coating efficiency.

  As a result of diligent study, the present inventor can efficiently generate inductive charging of the current collector by forming the electrode layer by supplying the charged electrode material onto the grounded current collector. The inventors have found that a charged electrode material can be efficiently applied, and that a polarizable electrode can be produced stably for a long time. Based on these findings, the following invention has been completed.

Thus, according to the present invention, the following [1] to [7] are provided.
[1] A method for producing a polarizable electrode, wherein an electrode layer is formed by supplying a charged electrode material onto at least one surface of a grounded current collector.
[2] The manufacturing method according to [1], wherein the current collector is a metal. [3] The electrochemical element according to [1] or [2], wherein the electrode material is composite particles containing the electrode active material. For manufacturing an electrode.
[4] The method for producing an electrode for an electrochemical element according to [1], wherein an average charge amount of the electrode material is 0.5 to 10.0 μC / g.
[5] An electrochemical element comprising a polarizable electrode obtained by the production method according to any one of [1] to [4].
[6] The electrochemical device according to [5], wherein the electrochemical device is an electric double layer capacitor.

  According to the present invention, a charged electrode material can be efficiently applied, and stable production can be performed for a long time. Therefore, it is possible to provide a method for producing a polarizable electrode with high productivity. is there. In particular, it can be suitably used as a method for producing an electrode for an electric double layer capacitor or a hybrid capacitor.

  The method for producing a polarizable electrode of the present invention is characterized in that an electrode layer is formed on at least one surface of a current collector grounded with a charged electrode material.

<Current collector>
As the current collector used in the production method of the present invention, specifically, a metal, carbon, a conductive polymer, or the like can be used, and a metal is preferably used. As the current collector metal, aluminum, platinum, nickel, tantalum, titanium, other alloys and the like are usually used. Among these, it is preferable to use copper, aluminum, or an aluminum alloy in terms of conductivity and voltage resistance.

  The shape of the current collector is not particularly limited, but is in the form of a film or a sheet, and the sheet-like current collector may have pores. The sheet-like current collector may have a shape such as an expanded metal, a punching metal, or a net. When a sheet-like current collector having pores is used, the capacity per volume of the obtained electrode can be increased. When the sheet-like current collector has holes, the ratio of the holes is preferably 10 to 79 area%, more preferably 20 to 60 area%.

  Although the thickness of a collector is suitably selected according to the intended purpose, it is 1-200 micrometers normally, Preferably it is 5-100 micrometers, More preferably, it is 10-50 micrometers. When the thickness of the current collector is in this range, the resistance of electron movement can be reduced, and the internal resistance can be reduced.

  Moreover, you may use what applied the conductive adhesive to the surface as a collector. 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 for the conductive adhesive, any of those exemplified as the binder used in the electrode material used in the production method of the present invention described later can be used. Moreover, water glass, an epoxy resin, a polyamideimide resin, a urethane resin, etc. can also be used, and these can be used individually or in combination of 2 or more types, respectively. The binder of the conductive adhesive is preferably an acrylate polymer, an ammonium salt or alkali metal salt of carboxymethyl cellulose, water glass, or a 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 in the production method of the present invention can be used.

<Electrode material>
The electrode material used in the method for producing a polarizable electrode of the present invention is an electrode active material, a conductive agent, a binder, and other materials necessary for constituting an electrode, and usually has a solid particle form. This is what you are doing.

(Electrode active material)
What is necessary is just to select the electrode active material used for the polarizable electrode obtained by the manufacturing method of this invention according to the element for which an electrode is utilized.
When the polarizable electrode obtained by the production method of the present invention is used for an electrode for an electric double layer capacitor or a positive electrode for a hybrid capacitor, an allotrope of carbon is usually used as the electrode active material. 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 electrode active material is activated carbon, and specific examples include activated carbon made from phenol resin, rayon, acrylonitrile resin, pitch, coconut shell, and the like.

  When the polarizable electrode obtained by the production method of the present invention is used as an electrode for a hybrid capacitor negative electrode, the electrode active material includes amorphous carbon, graphite, natural graphite, mesocarbon microbeads (MCMB), and pitch system Examples thereof include carbonaceous materials such as carbon fibers; conductive polymers such as polyacene; Si, Sn, Sb, Al, Zn, and W that can be alloyed with lithium.

  The volume average particle diameter of the electrode active material used in the present invention is usually 0.1 to 100 μm, preferably 1 to 50 μm, and more preferably 5 to 20 μm.

The specific surface area of the electrode active material used in the present invention, ^{30 m} 2 / g or more, preferably preferably 500~5,000m ² / g, more preferably 1,000~3,000m ² / g. Since the density of the obtained electrode composition layer tends to decrease as the specific surface area of the electrode active material increases, an electrode composition layer having a desired density can be obtained by appropriately selecting the electrode active material. Moreover, these electrode active materials can be used individually or in combination of 2 or more types.

(Conductive material)
The conductive material used in the present invention is composed of an allotrope of particulate carbon that has conductivity and does not have pores that can form an electric double layer. Specifically, furnace black, acetylene black, and kettle are used. Examples thereof include conductive carbon black such as chain black (registered trademark of Akzo Nobel Chemicals Besloten Fennaut Shap); graphite such as natural graphite and artificial graphite. Among these, conductive carbon black is preferable, and acetylene black and ketjen black are more preferable.

  The volume average particle diameter of the conductive material used in the present invention is preferably smaller than the volume average particle diameter of the electrode active material, and the range thereof is usually 0.001 to 10 μm, preferably 0.05 to 5 μm, more preferably. 0.01 to 1 μm. When the volume average particle diameter of the conductive material is within this range, high conductivity can be obtained with a smaller amount of use. These conductive materials can be used alone or in combination of two or more. When the amount of the conductive material is increased, the charge amount of the electrode material described later can be reduced, and when the amount is decreased, the charge amount can be increased. The amount of the conductive material is usually 0.1 to 50 parts by weight, preferably 0.5 to 15 parts by weight, and more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the electrode active material. When the amount of the conductive material is within this range, when the polarizable electrode obtained is used as an electrode for an electric double layer capacitor, the capacity of the electric double layer capacitor used can be increased and the internal resistance can be decreased.

(Binder)
The binder used in the present invention is not particularly limited as long as it is a compound capable of binding electrode active materials to each other. A suitable binder is a dispersion type binder having a property of being dispersed in a solvent. Examples of the dispersion-type binder include polymer compounds such as fluorine-based polymers, diene-based polymers, acrylate-based polymers, polyimides, polyamides, polyurethane-based polymers, and preferably fluorine-based polymers and diene-based binders. A polymer and an acrylate polymer, more preferably a diene polymer and an acrylate polymer. When the method of charging the electrode material is frictional charging with polytetrafluoroethylene, the charge amount described later can be adjusted by utilizing the relationship of the charge train. For example, since the acrylate polymer is more likely to be positively charged on the charged column than the diene polymer, the charge amount can be increased.

  The shape of the binder used in the production method of the present invention is not particularly limited, but has good binding properties, and can suppress deterioration due to repeated decrease in capacity and charge / discharge of the created electrode. It is preferably in the form of particles. Examples of the particulate binder include those in which binder particles such as latex are dispersed in water, and powders obtained by drying such a dispersion.

  The number average particle size of the binder used in the production method of the present invention 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. It has a number average particle size. When the number average particle diameter of the binder is within this range, an excellent binding force can be imparted to the polarizable electrode 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. These binders can be used alone or in combination of two or more. The amount of the binder is usually 0.1 to 50 parts by weight, preferably 0.5 to 20 parts by weight, and more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the electrode active material. When the amount of the binder is within this range, sufficient adhesion between the obtained electrode composition layer and the current collector can be secured, and when the obtained polarizable electrode is used as an electrode for an electric double layer capacitor, The capacitance of the double layer capacitor can be increased and the internal resistance can be decreased. Further, when the amount of the binder is increased, the charge amount of the electrode described later can be increased, and when the amount of the binder is decreased, the charge amount can be decreased.

  In addition, the manufacturing method of the present invention may contain the following materials necessary for constituting the electrode.

(Dispersant)
The dispersing material is used by being dissolved in a slurry solvent described later, 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.

  These dispersing agents can be used alone or in combination of two or more. 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 to 100 parts by weight of the electrode active material. The range is ˜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.

  Examples of other additives include a surfactant. 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.

  Surfactant can be used individually or in combination of 2 or more types. 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 has the above-mentioned electrode active material and binder as essential components, and has a particle shape containing a conductive material, a dispersing material, and other additives as necessary (hereinafter referred to as “ It is preferable to be referred to as “composite particles”.

  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 in the vicinity of the surface can be easily obtained. When composite particles obtained by the spray drying granulation method are used, the polarizable electrode of the present invention can be obtained with high productivity. In addition, the internal resistance of the electrode can be further reduced.

  The weight average particle diameter of the composite particles used in the present invention is usually in the range of 0.1 to 1,000 μm, preferably 5 to 500 μm, more preferably 10 to 100 μm. When the weight average particle diameter of the composite particles is within this range, the composite particles are less likely to aggregate and electrostatic force is increased against gravity, which is preferable.

  In the present invention, the electrode layer is formed by supplying the charged electrode material onto at least one surface of the grounded current collector.

To charge the electrode material means to charge the electrode material positively or negatively by treating the electrode material.
The method for charging the electrode material is not particularly limited, and examples thereof include a method for charging by directly applying a voltage to the electrode material, a method for charging the electrode material by friction, and the like.

  As a method of charging by directly applying a voltage to the electrode material, a charging method using corona discharge can be mentioned. In the charging method using corona discharge, when the electrode material is sprayed on the current collector, it may be charged by passing through the vicinity of the corona discharge electrode. May be charged.

  As a method of charging the electrode material by friction, a method of charging the electrode material by contacting the electrode material and a material that is easily charged using a charging train is used. The charged column is inherent to a substance and has a relative order of easiness of charging from a material that is easily charged negatively to a material that is easily charged positively. As the two materials to be rubbed are more apart from each other on the charge train, each of them is charged more greatly. Therefore, on the charge train, the electrode material is easily brought into contact with the electrode material by contacting the material away from the electrode train from the electrode train. Can be charged. When the electrode material is positively charged, tetrafluoroethylene is the material that is most easily negatively charged on the charge train, and therefore the electrode material can be easily positively charged by contacting with polytetrafluoroethylene.

  The electrode material may be charged by mixing a plurality of the above-mentioned electrode materials. However, since the difference in chargeability between different electrode materials can be eliminated, the composite of the above-mentioned electrode materials is charged. It is preferable to make it.

<Charge amount>
The amount of charge when the electrode material is charged can be measured as the average amount of charge of the electrode material by measuring the amount of current that the oppositely charged material flows to the ground when the electrode material is charged. The average charge amount of the electrode material is usually 0.5 μC / g or more, preferably 0.5 to 10.0 μC / g, more preferably 1.5 to 6.0 μC / g. When the average charge amount is within this range, the electrode material can be more efficiently applied on the current collector. As described above, the charge amount can be adjusted by changing the amount and type of the conductive material and the binder.

<Grounding>
In the present invention, the current collector is required to be grounded. The ground resistance of the current collector is usually 1 MΩ or less, preferably 100Ω or less. When the ground resistance is within this range, effective induction charging is induced in the current collector when the charged electrode material approaches the vicinity of the current collector, so that a uniform electrode can be formed.

<Formation of electrode layer>
(Electrode material supply method)
In the present invention, the charged electrode material is supplied onto at least one surface of the grounded current collector. There is no particular limitation on the method of supplying the charged electrode material onto the current collector. For example, a charged electrode material may be sprayed and supplied to a grounded current collector as in electrostatic powder coating, or charged to a current collector installed as in electrostatic screen printing. The electrode material may be transferred.

  Then, the current collector and the electrode material supplied on the one surface by the supply method are pressurized with a pair of rolls to form an electrode layer on the current collector. In this step, the electrode material heated as necessary may be formed into a sheet-like electrode layer with 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. A sheet for polarizable electrodes with small variations can be obtained.

  In the present invention, 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 or higher than the melting point or glass transition temperature of the binder. preferable. In the case of using a press roll, the forming speed is usually 10 m / min or more, preferably 20 to 200 m / min, more preferably 30 to 80 m / min, in order to make the moldability higher and to make the film easier. . Further, the press linear pressure between the press rolls is not particularly specified, but is preferably 0.2 to 30 kN / cm, more preferably 0.5 to 10 kN / cm in that the electrode strength of the obtained electrode can be increased. is there.

  In 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 current collector is continuously supplied between a pair of rolls, and the electrode material is supplied to at least one of the rolls, so that the electrode material is placed in the gap between the current collector and the rolls. The electrode layer can be formed by being supplied and pressurized. In the case of disposing substantially vertically, the 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 leveled 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 order to eliminate the variation in the thickness of the molded body, increase the density, and increase the capacity, further pressurization may be performed as necessary. 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 roll may be temperature controlled, such as heated or cooled.

(Polarizable electrode)
A polarizable electrode is obtained by the production method of the present invention. A polarizable electrode refers to an electrode that has a potential range in which no current flows even when a potential is applied. The polarizable electrode obtained by the production method of the present invention is suitably used as an electrode for a capacitor such as an electric double layer capacitor or a hybrid capacitor.

(Electrochemical element)
The electrochemical device of the present invention includes a polarizable electrode obtained by the production method of the present invention. Examples of the electrochemical element include an electric double layer capacitor and a hybrid capacitor. An electric double layer capacitor is preferable. Hereinafter, the case where the polarizable electrode obtained by the manufacturing method of the present invention is used as an electrode for an electric double layer capacitor will be described.

  The electric double layer capacitor is composed of an electrode, a separator and an electrolytic solution, and the polarizable electrode obtained by the production method of the present invention is used as the electrode.

  A separator will not be specifically limited if it can insulate between the electrodes for electric double layer capacitors, and can let a cation and an anion pass. Specifically, polyolefins such as polyethylene and polypropylene, microporous membranes or nonwoven fabrics made of rayon or glass fiber, and porous membranes mainly made of pulp called electrolytic capacitor paper can be used. A separator is arrange | positioned between the electrodes for electric double layer capacitors so that said pair of electrode composition layer may oppose, and an element is obtained. Although the thickness of a separator is suitably selected according to a use purpose, it is 1-100 micrometers normally, Preferably it is 10-80 micrometers, More preferably, it is 20-60 micrometers.

The electrolytic solution is usually composed of an electrolyte and a solvent. As the electrolyte, (1) imidazolium, (2) quaternary ammonium, (3) quaternary phosphonium, (4) lithium and the like as shown below can be used as the cation.
(1) Imidazolium 1,3-Dimethylimidazolium, 1-ethyl-3-methylimidazolium, 1,3-diethylimidazolium, 1,2,3-trimethylimidazolium, 1,2,3,4-tetramethyl Imidazolium, 1,3,4-trimethyl-ethylimidazolium, 1,3-dimethyl-2,4-diethylimidazolium, 1,2-dimethyl-3,4-diethylimidazolium, 1-methyl-2,3 , 4-triethylmethylimidazolium, 1,2,3,4-tetraethylimidazolium, 1,3-dimethyl-2-ethylimidazolium, 1-ethyl-2,3-dimethylimidazolium, 1,2,3- Triethylimidazolium, etc. (2) Quaternary ammonium tetramethylammonium, ethyltrimethylammonium, diethyl (3) Quaternary phosphonium Tetramethylphosphonium, tetraethylphosphonium, tetrabutylphosphonium, methyltriethylphosphonium, methyltributylphosphonium, dimethyldiethylphosphonium, etc. ( 4) Lithium

Similarly, the electrolyte has PF ₆ ⁻ , BF ₄ ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , N (RfSO ₃ ) ²⁻ , C (RfSO ₃ ) ³⁻ , RfSO ₃ ⁻ (Rf is respectively A fluoroalkyl group having 1 to 12 carbon atoms), F ⁻ , ClO ₄ ⁻ , AlCl ₄ ⁻ , AlF ₄ ^{− and the} like can be used. These electrolytes can be used alone or in combination of two or more.

  The solvent of the electrolytic solution is not particularly limited as long as it is generally used as a solvent for the electrolytic solution. Specifically, carbonates such as propylene car boat, ethylene carbonate and butylene carbonate; lactones such as γ-butyrolactone; sulfolanes; nitriles such as acetonitrile; These can be used alone or as a mixed solvent of two or more. Of these, carbonates are preferred.

  An electric double layer capacitor is obtained by impregnating the capacitor element with an electrolytic solution. Specifically, the capacitor element can be manufactured by winding, stacking, or folding into a container as necessary, and pouring the electrolyte into the container and sealing it. Moreover, what impregnated the electrolytic solution beforehand in the capacitor element may be stored in the container. Any known container such as a coin shape, a cylindrical shape, or a square shape can be used as the container.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to these Examples. In addition, the part and% in an Example and a comparative example are mass references | standards unless there is particular notice.

<Example 1>
100 parts of high-purity activated carbon powder “Kuraray Coal YP-17D” (manufactured by Kuraray Chemical Co., Ltd.) having a specific surface area of 1,800 m ² / g and a volume average particle diameter of 5 μm as an electrode active material, and a core forming a core as a binder The constituent monomer units of the coalescence are n-butyl acrylate and ethyl methacrylate, the constituent monomer units of the polymer forming the shell portion are n-butyl methacrylate and methacrylic acid, and all monomer units The composition ratio is n-butyl acrylate: ethyl methacrylate: n-butyl methacrylate: methacrylic acid = 40: 40: 17: 3 (mass ratio), the glass transition temperature of the core part is −5 ° C., and the shell part. 5 parts of an aqueous dispersion latex (volume average particle size 0.31 μm, solid content concentration 40%) of a core-shell polymer having a glass transition temperature of 25 ° C. and an average particle size of 0.7 as a conductive material 5 parts of m acetylene black (Denka black powder; manufactured by Denki Kagaku Kogyo Co., Ltd.) and 93% of a 1.5% aqueous solution of ammonium salt of carboxymethyl cellulose (“DN-800H” (manufactured by Daicel Chemical Industries, Ltd.)) as a dispersant. .3 parts and 348.7 parts of ion-exchanged water were added and stirred and mixed with a “TK homomixer” (manufactured by Primics) to obtain a slurry having a solid content concentration of 20%. The pH of the slurry was 7.6 at 23 ° C. This slurry was adjusted to pH 8.5 with 25% aqueous ammonia, and using a spray dryer (OC-16; manufactured by Okawara Chemical Co., Ltd.), a rotating disk type atomizer (diameter 65 mm) with a rotation speed of 25,000 rpm and hot air Spray drying granulation was performed under the conditions of a temperature of 150 ° C. and a particle recovery outlet temperature of 90 ° C. to obtain composite particles of an electrode material. The composite particles had a weight average particle diameter of 54 μm.

  100 parts of carbon black having a volume average particle diameter of 0.7 μm and 4.0 parts of a carboxymethylcellulose 4.0% aqueous solution (DN-10L; manufactured by Daicel Chemical Industries) as a dispersant are equivalent to 4 parts in solid content and several parts as a binder. For forming a conductive adhesive layer by mixing a 40% aqueous dispersion of an acrylate polymer having an average particle diameter of 0.25 μm with a solid content equivalent of 8 parts and ion-exchanged water so that the total solid concentration is 30%. A slurry composition was prepared.

  The slurry composition for forming a conductive adhesive was applied to a current collector made of an aluminum foil having a thickness of 30 μm, and dried at 120 ° C. for 10 minutes to form a conductive adhesive layer having a thickness of 4 μm. A 30 μm thick aluminum foil was grounded and placed horizontally. The grounding resistance was 10Ω.

Next, the charging and supply of the electrode material were performed by the friction charging electrostatic powder coating machine MTR-100VTmini manufactured by Asahi Sunac Corporation and the friction charging powder manual gun T-2m type L7 manufactured by Asahi Sunac Corporation (the inner sleeve and outer sleeve are And made of polytetrafluoroethylene.). Specifically, the composite particles of the electrode material were put into the hopper of the powder coating machine, the rotation speed of the screw feeder for quantitative supply was adjusted, and the composite particles of the electrode material were supplied at 1.5 g / second. . Moreover, the electrode material was supplied to the said collector from the upper part by making the conveyance air pressure from the said powder manual gun into 0.4 Mpa. The electrode material was charged by frictional charging generated when passing through the gap between the inner sleeve and outer sleeve of the powder manual gun. The current value at this time was 1.0 μA (C / sec). The average charge amount of the charged electrode material was 0.7 μC / g. The coating efficiency on the current collector was calculated from the weight of the supplied electrode material and the weight of the electrode material in which the electrode material layer was formed on the current collector according to the following formula, and found to be 43%.
Coating efficiency (%) = weight of electrode material deposited on current collector / weight of supplied electrode material

When the appearance of the obtained electrode material layer was observed, it was confirmed that the electrode material was uniformly formed on the current collector. The current collector on which this electrode material layer is formed is supplied to a roll (roll temperature 120 ° C., press linear pressure 4 kN / cm) of a roll press machine (pressed rough surface heat roll, manufactured by Hirano Giken Kogyo Co., Ltd.), and roll pressure is applied. A sheet-like consolidated electrode layer was formed by molding to produce an electrode for an electric double layer capacitor having an electrode layer thickness of 60 μm and an electrode layer density of 0.58 g / cm ³ .

<Example 2>
In Example 1, an electrode having an electrode layer thickness of 60 μm and an electrode layer density of 0.58 g / cm ³ was obtained in the same manner as in Example 1 except that the amount of the water-dispersed latex used as the binder was 10 parts. Manufactured. There was no problem in the appearance of the electrode material layer, the current value at the time of supplying the electrode material was 3.0 μA (average charge amount 2.0 μC / g), and the coating efficiency was 60%.

<Example 3>
In Example 1, an electrode having an electrode layer thickness of 60 μm and an electrode layer density of 0.60 g / cm ³ was produced in the same manner as in Example 1 except that the amount of the water-dispersed latex used as the binder was 15 parts. did. There was no problem in the appearance of the electrode material layer, the current value at the time of supplying the electrode material was 7.5 μA (average charge amount 5.0 μC / g), and the coating efficiency was 67%.

<Example 4>
In Example 1, the amount of the water-dispersed latex used as the binder was 15 parts, and the electrode material supply rate was 0.8 g / sec. An electrode having an electrode layer density of 0.60 g / cm ³ was produced. There was no problem in the appearance of the electrode material layer, the current value at the time of supplying the electrode material was 13.5 μA (average charge amount 9.0 μC / g), and the coating efficiency was 45%.

<Example 5>
In Example 1, the amount of the water-dispersed latex used as the binder was 15 parts, and the electrode material supply amount was 0.5 g / sec. An electrode having an electrode layer density of 0.60 g / cm ³ was produced. There was no problem in the appearance of the electrode material layer, the current value when supplying the electrode material amount was 18 μA (average charge amount 12.0 μC / g), and the coating efficiency was 35%.

<Comparative Example 1>
In Example 1, the electrode layer was the same as in Example 1 except that the PTFE inner and outer sleeves of the triboelectric powder manual gun T-2m type L7 were replaced with stainless steel of the same shape. An electrode having a thickness of 60 μm and an electrode density of 0.58 g / cm ³ was produced. There was no problem in the appearance of the electrode material layer, the current value when supplying the electrode material was 0.0 μA (average charge amount was 0.0 μC / g), and the coating efficiency was 8%.

<Comparative example 2>
In Example 3, an electrode having an electrode layer thickness of 60 μm and an electrode density of 0.60 g / cm ³ was produced in the same manner as in Example 3 except that the aluminum foil was not grounded. A spark occurred during the supply of the electrode material, and the appearance of the electrode was impaired.

  The results of the above examples and comparative examples are shown in Table 1.

  From the results in Table 1, the following can be understood. In Comparative Example 1, since the electrode material is not charged, the coating efficiency of the electrode material is inferior. In Comparative Example 2, since the current collector is not grounded, the charged electrode material on the current collector causes a dielectric breakdown and sparks, which hinders the appearance of the electrode.

  The method for producing a polarizable electrode of the present invention is excellent in the appearance of the electrode and has a high coating efficiency of the electrode material, so that it can be suitably used for producing an electrode such as an electric double layer capacitor electrode or a hybrid capacitor electrode with high productivity. it can.

  Although the present invention has been described with reference to the most practical and preferred embodiments at the present time, the invention is limited to the embodiments disclosed herein. However, the present invention can be modified as appropriate without departing from the scope or spirit of the invention that can be read from the claims and the entire specification, and a method for manufacturing a polarizable electrode involving such a change is also included in the technical scope of the present invention. Must be understood as being.

Claims (6)

A method for producing a polarizable electrode, wherein an electrode layer is formed by supplying a charged electrode material onto at least one surface of a grounded current collector. The manufacturing method according to claim 1, wherein the current collector is a metal. The method for producing a polarizable electrode according to claim 1, wherein the electrode material is composite particles containing an electrode active material. The method for producing a polarizable electrode according to claim 1, wherein the electrode material has an average charge amount of 0.5 to 10.0 μC / g. An electrochemical element provided with the polarizable electrode obtained by the manufacturing method in any one of Claims 1-4. The electrochemical device according to claim 5, wherein the electrochemical device is an electric double layer capacitor.