WO2014030735A1

WO2014030735A1 - Lead battery capacitor electrode, lead capacitor battery, method for producing lead battery capacitor electrode and method for producing lead capacitor battery

Info

Publication number: WO2014030735A1
Application number: PCT/JP2013/072541
Authority: WO
Inventors: 祐子大谷
Original assignee: 日本ゼオン株式会社
Priority date: 2012-08-23
Filing date: 2013-08-23
Publication date: 2014-02-27

Abstract

The present invention provides: a lead battery capacitor electrode having superior strength and low resistance; a lead capacitor battery; and, in order to obtain same, a method for producing a lead battery capacitor electrode and a method for producing a lead capacitor battery. The lead battery capacitor electrode includes a capacitor layer disposed between an anode and a cathode; the capacitor layer includes a capacitor electrode active material, a conductive agent, and a binder; the binder density of the capacitor layer is in the range of 0.48-0.52 g/cm³ at the cathode side and anode side; and an electrolyte solution dispersive cellulose compound that disperses in an electrolyte solution is included.

Description

Capacitor electrode for lead storage battery, lead capacitor storage battery, method of manufacturing capacitor electrode for lead storage battery, and method of manufacturing lead capacitor storage battery

The present invention relates to a lead-acid battery capacitor electrode having excellent strength and low resistance, a lead-capacitor battery, a method for producing a lead-acid battery capacitor electrode, and a method for producing a lead-capacitor battery.

Lead-acid batteries that use lead dioxide as the positive electrode active material, lead as the negative electrode active material, and sulfuric acid as the electrolyte are inexpensive and suitable for high-current discharge in many industries compared to other secondary batteries. Even today, the importance of high-capacity secondary batteries such as lithium-ion secondary batteries is prominent, and their importance has not been lost.

In recent years, a technique using activated carbon has been reported regarding the improvement of short-time high-current discharge characteristics, which is an advantage of lead-acid batteries, and the improvement of cycle characteristics with a large discharge depth, which is a disadvantage.

For example, increasing the charging speed of a lead storage battery or providing a capacitor layer between the positive electrode and the negative electrode in order to improve the depth of discharge. In Patent Document 1, a capacitor layer is formed by applying a slurry for forming a capacitor layer on a lead electrode plate. In Patent Document 2, (i) a capacitor layer is formed on a PET (polyethylene terephthalate) film used as a support by a dry method, the capacitor layer is pressure-bonded on a lead electrode plate, and then the PET film is peeled off. Method (ii) A method of forming a capacitor layer on a PET film used as a support by a dry method, peeling the PET film, and pressing the capacitor layer on a lead electrode plate is disclosed.

JP 2011-71110 A JP 2010-192417 A

However, when the slurry is applied and dried as in Patent Document 1, binder migration occurs, and thus the resistance of the obtained lead capacitor storage battery increases. Further, in the case of Patent Document 2, if the PET film is peeled off after being pressure-bonded to the lead electrode as in (i), the strength of the capacitor layer is weakened. Since the PET film becomes a resistance component, the resistance of the obtained lead capacitor storage battery increases. Further, when the capacitor layer is formed by a dry method as in (ii) and the PET film is peeled off and the capacitor layer is pressure-bonded on the lead electrode plate, the capacitor is formed on the lead electrode plate without a support. Since the layers are pressure-bonded, the strength of the capacitor layer is weakened.

An object of the present invention is to provide a capacitor electrode for a lead storage battery, a lead capacitor storage battery, a method for manufacturing a capacitor electrode for lead storage battery, and a method for manufacturing a lead capacitor storage battery, which have excellent strength and low resistance.

As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that the above-mentioned object can be achieved by containing an electrolyte-dispersible cellulose in the capacitor electrode, and has completed the present invention.

That is, according to the present invention,
(1) A capacitor electrode for a lead storage battery that is disposed between a negative electrode and a positive electrode and includes a capacitor layer, the capacitor layer including a capacitor electrode active material, a conductive agent, and a binder, and binding of the capacitor layer The agent density is in the range of 0.48 to 0.52 g / cm ³ on the positive electrode side and the negative electrode side,
A capacitor electrode for a lead storage battery comprising an electrolytic solution-dispersible cellulose compound dispersed in an electrolytic solution.
(2) The capacitor electrode for a lead storage battery according to (1), wherein the capacitor layer contains electrolyte-insoluble cellulose.
(3) The capacitor electrode for a lead storage battery according to claim 2, wherein the ratio of the electrolyte-insoluble cellulose in the capacitor layer is 0.1 to 10 parts by weight with respect to 100 parts by weight of the capacitor electrode active material.
(4) The capacitor electrode active material according to any one of (1) to (3), wherein the capacitor electrode active material is activated carbon starting from petroleum pitch.
(5) The capacitor electrode for a lead storage battery according to any one of (1) to (4), wherein the binder is a diene polymer,
(6) A lead capacitor storage battery comprising the capacitor electrode for a lead storage battery according to any one of (1) to (5), a negative electrode, a positive electrode, a separator, and an electrolytic solution,
(7) A step of granulating composite particles containing a capacitor electrode active material, a conductive agent and a binder, and a capacitor layer containing the composite particles by a dry method on a support made of electrolyte-dispersible cellulose. A method for producing a lead-acid battery capacitor electrode, comprising a sheet forming step,
(8) In the step of forming the sheet, the composite particles and a support made of electrolyte-dispersible cellulose are supplied to a pair of press rolls or belts arranged substantially horizontally, and the pair of press rolls Alternatively, a capacitor layer is obtained by molding the composite particles into a sheet-like molded body using a belt, and the capacitor layer is produced by pressure-bonding it to the surface of the support. (7) Method,
(9) A step of granulating composite particles containing a capacitor electrode active material, a conductive agent and a binder, and forming a capacitor layer containing the composite particles on the roughened or release-treated support surface A method for producing a capacitor electrode for a lead storage battery, comprising: a step of transferring the capacitor layer onto a support made of an electrolyte-dispersible cellulose;
(10) The step of forming the capacitor layer includes supplying the composite particles and a roughened or release-treated support to a pair of press rolls or belts arranged substantially horizontally, A lead-acid battery according to (9), which is a step of obtaining a capacitor layer by molding the composite particles into a sheet-like molded body with a pressing roll or belt, and crimping the capacitor layer to the surface of the support. Manufacturing method of capacitor electrode,
(11) A method of manufacturing a lead capacitor storage battery including a step of laminating a lead storage battery capacitor electrode obtained by the method of manufacturing a lead capacitor storage battery according to any one of (7) to (10) and a lead active material layer is provided. Is done.

According to the present invention, there are provided a lead-acid battery capacitor electrode having excellent strength and low resistance, a lead-capacitor battery, a method for producing a lead-acid battery capacitor electrode for obtaining these, and a method for producing a lead-capacitor battery.

It is a figure which shows the specific aspect of the manufacturing process of the capacitor layer of this invention. It is a schematic sectional drawing which shows the lead capacitor storage battery of this invention.

Hereinafter, a capacitor electrode for a lead storage battery according to an embodiment of the present invention will be described. The capacitor electrode for a lead storage battery of the present invention is a capacitor electrode for a lead storage battery that is disposed between a negative electrode and a positive electrode and includes a capacitor layer, the capacitor layer including a capacitor electrode active material, a conductive agent, and a binder, The capacitor layer has a binder density in the range of 0.48 to 0.52 g / cm ³ on the positive electrode side and the negative electrode side, and includes an electrolytic solution-dispersible cellulose compound dispersed in the electrolytic solution.

(Capacitor layer)
The capacitor layer used in the present invention includes a capacitor electrode active material, a conductive agent, and a binder.

(Capacitor electrode active material)
The capacitor electrode active material used in the present invention is a substance that transfers electrons in the electrode.
As the capacitor electrode active material used in the present invention, an electrode active material used for an electric double layer capacitor electrode, specifically, an allotrope of carbon is used. Specific examples of the allotrope of carbon include activated carbon, polyacene, carbon whisker, and graphite, and these powders or fibers can be used. The preferred electrode active material is activated carbon. Specifically, activated carbon made from phenol resin, rayon, acrylonitrile resin, petroleum pitch, coconut shell, etc. is preferred. From the viewpoint of adhesion to the lead plate, petroleum pitch is used as a raw material. More preferred is activated carbon.

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

The specific surface area of the capacitor electrode active material 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. Since the density of the obtained capacitor layer tends to decrease as the specific surface area of the capacitor electrode active material increases, a capacitor layer having a desired density can be obtained by appropriately selecting the capacitor electrode active material.

(Conductive agent)
The conductive agent used in the present invention comprises an allotrope of particulate carbon that has conductivity and does not have pores that can form an electric double layer, and specifically includes furnace black, acetylene black, and ketjen. Examples thereof include conductive carbon black such as black (registered trademark of Akzo Nobel Chemicals Bethloten Fennaut Shap). Among these, acetylene black and ketjen black are preferable.

The volume average particle diameter of the conductive agent used in the present invention is preferably smaller than the volume average particle diameter of the capacitor electrode active material, and is usually 0.001 to 10 μm from the viewpoint of obtaining high conductivity with a smaller use amount. The thickness is preferably 0.005 to 5 μm, more preferably 0.01 to 1 μm. These conductive agents can be used alone or in combination of two or more.
The amount of the conductive agent is usually 0.1 to 50 weights with respect to 100 parts by weight of the capacitor electrode active material from the viewpoint of increasing the capacity of the lead storage battery using the obtained lead storage battery electrode and reducing the internal resistance. Parts, preferably 0.5 to 15 parts by weight, more preferably 1 to 10 parts by weight.

(Binder)
The binder used for the capacitor layer is not particularly limited as long as it is a compound that can bind the capacitor electrode active material and the conductive agent 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 fluoropolymers, diene polymers, acrylic polymers, polyimides, polyamides, polyurethane polymers, and diene polymers and acrylic polymers are 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. 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); acrylonitrile -Vinyl cyanide * conjugated diene copolymers, such as a butadiene copolymer (NBR); Hydrogenated SBR, hydrogenated NBR, etc. are mentioned.

The acrylic polymer is a copolymer obtained by polymerizing a homopolymer of acrylic ester or methacrylic ester or a monomer mixture containing a monomer copolymerizable therewith. Examples of the copolymerizable monomer include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, and fumaric acid; two or more carbons such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, and trimethylolpropane triacrylate. Carboxylates having carbon double bonds; styrene, chlorostyrene, vinyl toluene, t-butyl styrene, vinyl benzoic acid, methyl vinyl benzoate, vinyl naphthalene, chloromethyl styrene, hydroxymethyl styrene, α-methyl styrene, Styrenic monomers such as divinylbenzene; Amide monomers such as acrylamide, N-methylolacrylamide, and acrylamide-2-methylpropanesulfonic acid; α, β-insoluble such as acrylonitrile and methacrylonitrile Japanese nitrile compounds; olefins such as ethylene and propylene; diene monomers such as butadiene and isoprene; monomers containing halogen atoms such as vinyl chloride and vinylidene chloride; vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate Vinyl esters such as methyl vinyl ether, ethyl vinyl ether, and butyl vinyl ether; vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, butyl vinyl ketone, hexyl vinyl ketone, and isopropenyl vinyl ketone; N-vinyl pyrrolidone, Examples thereof include heterocyclic compounds containing vinyl rings such as vinylpyridine and vinylimidazole; compounds containing hydroxyalkyl groups such as β-hydroxyethyl acrylate and β-hydroxyethyl methacrylate.

Among these, it is preferable to use a diene polymer from the viewpoint of strength when dry forming into composite particles together with a capacitor electrode active material and a conductive agent, and an acrylonitrile-butadiene copolymer (hereinafter referred to as “NBR”). It is more preferable to use. In the case of using the acrylonitrile-butadiene copolymer, the ratio of the 1,3-butadiene monomer unit in the binder is preferably 40 to 75% by weight, and 45 to 75% by weight. Is more preferable. Further, when the acrylonitrile-butadiene copolymer is used, the ratio of the acrylonitrile monomer unit in the binder is preferably 20 to 60% by weight, and more preferably 20 to 45% by weight.

The acrylonitrile-butadiene copolymer preferably further contains monomer units of the aforementioned unsaturated carboxylic acids such as acrylic acid and methacrylic acid in addition to 1,3-butadiene and acrylonitrile. As unsaturated carboxylic acids, methacrylic acid is preferable. In this case, the lower limit of the ratio of the unsaturated carboxylic acid monomer in the binder is preferably 3% by weight or more, more preferably 5% by weight or more, and the upper limit is 39% by weight. Or less, more preferably 35% by weight or less.

The glass transition temperature (hereinafter referred to as “Tg”) of the binder used in the present invention is preferably −40 to + 40 ° C., more preferably −30 to + 30 ° C. When the Tg of the binder is too high, the obtained capacitor layer is inferior in flexibility, and when the Tg of the binder is too low, it is difficult to mold the capacitor layer. Further, the binder may have a melting point.

The shape of the binder is most preferably particulate in order to minimize binding, increase in electrode capacity, and increase in internal resistance, for example, a binder such as latex. Examples include resin particles dispersed in a solvent and powders obtained by drying such a dispersion.

The particle size of the binder is not particularly limited, but the volume average particle size is preferably 100 to 500 nm.

The method for producing the binder is not particularly limited, and a known polymerization method such as an emulsion polymerization method, a suspension polymerization method, a dispersion polymerization method or a solution polymerization method using a composition containing each monomer at a predetermined ratio is used. Can be adopted. Among them, it is preferable to produce by an emulsion polymerization method because the particle diameter of the binder is easy to control. In particular, an aqueous polymerization method using water as a main solvent is preferred.

(Electrolyte insoluble cellulose)
The capacitor layer used in the present invention preferably further contains an electrolyte-insoluble cellulose.
Examples of the electrolyte-insoluble cellulose include cellulose polymers such as carboxymethylcellulose, methylcellulose, ethylcellulose, and hydroxypropylcellulose, and ammonium salts or alkali metal salts thereof. From the viewpoint of reducing the internal resistance of the lead capacitor storage battery, it is preferable to use carboxymethyl cellulose, an ammonium salt or an alkali metal salt thereof, and more preferably an ammonium salt of carboxymethyl cellulose. The electrolyte-insoluble cellulose in the present invention is insoluble in sulfuric acid used as the electrolyte and is different from the electrolyte-dispersible cellulose described below.

In addition, the ratio of the electrolyte-insoluble cellulose is preferably 0.1 to 10 parts by weight, more preferably 0.8 to 2.5 parts by weight with respect to 100 parts by weight of the capacitor electrode active material. By setting the ratio of the electrolyte-insoluble cellulose in the above range, the stability of the slurry described later can be improved, and the life characteristics of the obtained lead capacitor storage battery can be improved.

In addition to or in place of the electrolyte-insoluble cellulose, (modified) poly (meth) acrylic acid and ammonium salts thereof and alkali metal salts; (modified) polyvinyl alcohol, acrylic acid or acrylic acid Polyvinyl alcohols such as copolymers of salts and vinyl alcohol, maleic anhydride or maleic acid or copolymers of fumaric acid and vinyl alcohol; polyethylene glycol, polyethylene oxide, polyvinyl pyrrolidone, modified polyacrylic acid, oxidized starch, phosphoric acid Thickeners such as starch, casein, various modified starches, chitin and chitosan derivatives may be used.

When the above thickener is used as a dispersant, these dispersants can be used alone or in combination of two or more. Among them, the dispersant is preferably a cellulosic polymer, such as carboxymethylcellulose or ammonium thereof. Particularly preferred are salts or alkali metal salts. The amount of the dispersant 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 2 parts per 100 parts by weight of the electrode active material. .5 parts by weight. By using a dispersing agent, sedimentation and aggregation of solid content in the slurry can be suppressed.

The capacitor layer may further contain other additives as necessary. Specifically, in order to improve the electrical stability of the slurry described later, amphoteric surfactants such as anionic, cationic, nonionic or nonionic anions, aminocarboxylic acid chelate compounds, phosphonic acids And chelate compounds such as chelates, gluconic acid, citric acid, malic acid and tartaric acid.

(Capacitor layer manufacturing method)
The capacitor layer used in the present invention includes a capacitor electrode active material, a conductive agent, a binder, and other components used as necessary. In the capacitor electrode for a lead storage battery of the present invention, the capacitor layer is provided on the support, but the method of forming the capacitor layer on the support is not limited.

As a method for forming a capacitor layer on a support, composite particles comprising a capacitor electrode active material, a binder and a conductive agent and the optional components used as necessary are prepared, and this is formed on a sheet. A method (dry molding method) obtained by molding and roll molding as necessary is preferable in that the capacity of the lead storage battery can be increased and the internal resistance can be reduced.

(Dry molding method)
(Preparation of composite particles)
When the capacitor layer used in the present invention is molded by a dry molding method, the capacitor layer composition for forming the capacitor layer includes, as described above, the essential components of the capacitor electrode active material, the conductive agent and the binder, and the electrolytic solution. A composite particle comprising an optional component such as insoluble cellulose and a dispersant is preferred. When the capacitor layer slurry is composite particles, the electrode strength of the obtained lead storage battery electrode can be increased, or the internal resistance can be reduced.
The composite particle as used in the present invention refers to a particle in which a plurality of materials such as a capacitor electrode active material, an essential component of a conductive agent and a binder, and an optional component such as a dispersant are integrated. In addition, composite particles that can be suitably used are produced by granulation using an essential component of a capacitor electrode active material, a conductive agent and a binder, and optional components such as an electrolyte-insoluble cellulose and a dispersant. .

The granulation method of the composite particles is not particularly limited, and is spray drying granulation method, rolling bed granulation method, compression granulation method, stirring granulation method, extrusion granulation method, crushing granulation method, fluidized bed 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 a binder and a conductive agent are unevenly distributed near the surface can be easily obtained. By using the composite particles obtained by the spray-drying granulation method, the lead-acid battery electrode can be obtained with high productivity. In addition, the internal resistance of the electrode can be further reduced.

In the spray-drying granulation method, first, the capacitor electrode active material, the essential components of the conductive agent and the binder, and optional components such as the electrolyte solution insoluble cellulose and the dispersant are dispersed or dissolved in a solvent to obtain the capacitor electrode active material. A slurry is obtained in which the essential components of the substance, conductive agent and binder, and optional components such as electrolyte-insoluble cellulose and dispersant are dispersed or dissolved.

The solvent used for obtaining the slurry is not particularly limited, but when the above dispersant is used, a solvent capable of dissolving the dispersant is preferably used. Specifically, water is usually used, but an organic solvent may be used, or a mixed solvent of water and 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 and N-methyl- Amides such as 2-pyrrolidone and dimethylimidazolidinone; sulfur solvents such as dimethyl sulfoxide and sulfolane; and the like. Among these, alcohols are preferable as the organic solvent. When water and an organic solvent having a lower boiling point than water are used in combination, the drying rate can be increased during spray drying. Further, the dispersibility of the binder or the solubility of the dispersant varies depending on the amount or type of the organic solvent used in combination with water. Thereby, the viscosity and fluidity | liquidity of a slurry can be adjusted and 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. . When the solid content concentration is in this range, the binder is preferably dispersed uniformly.

A method or procedure for dispersing or dissolving the essential components of the capacitor electrode active material, the conductive agent and the binder and the optional components such as the electrolyte-insoluble cellulose and the dispersant in the solvent is not particularly limited. A method in which an electrode active material, a conductive agent, a binder, an electrolyte-insoluble cellulose and a dispersant are added and mixed; after the dispersant is dissolved in a solvent, a binder (for example, latex) dispersed in the solvent is added Finally, the capacitor electrode active material, conductive agent and electrolyte-insoluble cellulose are added and mixed; the capacitor electrode active material, conductive agent and electrolyte-insoluble cellulose are added to the binder dispersed in the solvent And a method in which a dispersant dissolved in a solvent is added to the mixture 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, a homomixer, 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 viscosity of the slurry is usually in the range of 10 to 3,000 mPa · s, preferably 30 to 1,500 mPa · s, more preferably 50 to 1,000 mPa · s at room temperature. When the viscosity of the slurry is within this range, the productivity of the composite particles can be increased. Moreover, the higher the viscosity of the slurry, the larger the spray droplets, and the larger the volume average particle diameter of the resulting composite particles.

Next, the slurry obtained above is spray-dried and granulated to obtain composite particles. Spray drying is performed by spraying the slurry in hot air and drying. An atomizer is used as an apparatus used for spraying slurry. 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 a high speed, and the slurry is released out of the disk by the centrifugal force of the disk, and the slurry is atomized at that time. 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 lower the rotational speed of the disk, the larger the spray droplets and the larger the volume average particle diameter of the resulting composite particles. Examples of the rotating disk type atomizer include a pin type and a vane type, and a pin type atomizer is preferable. A pin-type atomizer is a type of centrifugal spraying device that uses a spraying plate, and the spraying plate has a plurality of spraying rollers attached between upper and lower mounting disks in a substantially concentric manner along its periphery. It consists of The slurry is introduced from the center of the spray platen, adheres to the spraying roller by centrifugal force, moves outside the roller surface, and finally sprays away from the roller surface. On the other hand, 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. In spray drying, the method of blowing hot air is not particularly limited, for example, a method in which the hot air and the spray direction flow in the horizontal direction, a method in which the hot air is sprayed at the top of the drying tower and descends with the hot air, and the sprayed droplets and hot air are in countercurrent contact. And a system in which sprayed droplets first flow in parallel with hot air and then drop by gravity to make countercurrent contact.

複合 Composite particles are obtained by spray drying. The volume average particle diameter of the composite particles is usually 0.1 to 1000 μm, preferably 1 to 80 μm, more preferably 10 to 65 μm, from the viewpoint of good fluidity and enabling thinning. Here, the volume average particle diameter of the composite particles is a volume average particle diameter measured by pressurizing and spraying the composite particles with compressed air using a laser diffraction particle size distribution analyzer.

The composite particles are preferably spherical. Whether the composite particles are spherical or not is evaluated by (Ll−Ls) / {(Ls + Ll) / 2} where Ls is the minor axis diameter of the composite particles and Ll is the major axis diameter. (Hereinafter referred to as “sphericity”). Here, the minor axis diameter Ls and the major axis diameter Ll are average values for 100 arbitrary composite particles measured from a photographic image obtained by observing the composite particles using a reflection electron microscope. The smaller this value, the closer the spherical composite particle is to a true sphere.

For example, the particle observed as a square in the photographic image has a sphericity of 34.4%, so the composite particle showing a sphericity exceeding 34.4% is not at least spherical. The sphericity of the composite particles is preferably 20% or less, and more preferably 15% or less.

The composite particles obtained by the above production method can be subjected to post-treatment after production of the particles, if necessary. As a specific example, the fluidity of spherical composite particles is improved by modifying the particle surface by mixing the composite electrode with the capacitor electrode active material, conductive agent, binder, electrolyte-insoluble cellulose, or additive. Can be improved or decreased, continuous pressure moldability can be improved, and the electrical conductivity of the spherical composite particles can be improved.

(Roll molding)
When the capacitor layer of the present invention is produced by a dry molding method, a capacitor layer made of a capacitor electrode composition such as composite particles is directly formed on a support by roll molding to obtain a capacitor electrode for a lead storage battery (hereinafter referred to as “capacitor electrode”). , “First manufacturing method”), a capacitor layer composed of a capacitor electrode composition such as composite particles is formed on a first support by roll forming, and the obtained capacitor layer is formed on a second support. And a method of obtaining a capacitor electrode for a lead storage battery (hereinafter referred to as “second manufacturing method”). In addition, the collector used for a lead electrode is not contained in the support body in a 1st manufacturing method, and the 1st support body and 2nd support body in a 2nd manufacturing method.

(First manufacturing method)
In the first production method, the capacitor electrode composition such as composite particles and the support are supplied to a pair of press rolls or belts arranged substantially horizontally, and the pair of press rolls or belts A capacitor layer is obtained by molding the capacitor electrode composition into a sheet-like molded body, and this is pressure-bonded to the surface of the support.

The support used in the first manufacturing method is used for supporting the capacitor layer and further bonding the capacitor layer to the lead electrode. In the present invention, as the material constituting the support, Electrolyte-dispersible cellulose can be used. The thickness of the support made of the electrolyte-dispersible cellulose is not particularly limited, but is preferably 10 to 50 μm, and more preferably 20 to 40 μm. The width is not particularly limited, but is preferably 100 to 1000 mm, more preferably 100 to 500 mm. The tensile strength of the support made of the electrolyte-dispersible cellulose is not particularly limited, but is preferably 30 to 500 MPa, more preferably 30 to 300 MPa from the viewpoint of preventing breakage during the production of the capacitor layer. Although the manufacturing method of the support body which consists of electrolyte solution dispersible cellulose is not specifically limited, It is preferable to manufacture through a pulping process, an adjustment process, a papermaking process, and a finishing process.

(Electrolyte dispersible cellulose)
The electrolytic solution-dispersible cellulose used in the present invention is used as a support in forming the capacitor layer. Further, the electrolytic solution-dispersible cellulose is dispersed in sulfuric acid used as an electrolytic solution.

The electrolyte-dispersible cellulose is preferably wood-derived cellulose, and is preferably a short fiber (for example, a length of 1 to 2 mm and a width of about 20 μm). If the length or width of the electrolyte-dispersible cellulose fiber is too large, it is difficult to disperse in the electrolyte solution, and if the length or width of the electrolyte-dispersible cellulose fiber is too small, the strength of the obtained capacitor layer becomes weak.

In addition, the amount of the electrolyte-dispersible cellulose in the electrolyte in the obtained lead capacitor storage battery is preferably 3 to 100 parts by weight with respect to 100 parts by weight of the capacitor electrode active material in the capacitor layer from the viewpoint of extending the life of the lead capacitor storage battery. 30 parts by weight, more preferably 10 to 30 parts by weight. If the amount of the electrolyte-dispersible cellulose in the electrolyte is too large, the resistance of the lead capacitor storage battery increases due to the influence of the electrolyte-dispersible cellulose in the electrolyte. Moreover, the lifetime characteristic of the lead capacitor storage battery obtained can be improved more by making the quantity of the electrolyte-dispersible cellulose in electrolyte solution into the said range. In addition, the quantity of the electrolyte solution dispersible cellulose in electrolyte solution can be adjusted with the kind of electrolyte solution dispersible cellulose to be used.

(Second manufacturing method)
In the second production method, the capacitor electrode composition such as composite particles and the first support are supplied to a pair of press rolls or belts arranged substantially horizontally, and the pair of press rolls or A capacitor layer is obtained by molding the capacitor electrode composition into a sheet-like molded body using a belt, and this is pressure-bonded to the surface of the first support. Next, the capacitor layer bonded to the first support is transferred to the second support.

As the first support, a support having a roughened surface or a release-treated support is used. In addition, as the second support, a support made of an electrolytic solution-dispersed cellulose used as the support in the first manufacturing method described above can be used.

FIG. 1 shows a method of supplying a capacitor electrode composition and a first support having a surface roughened or released to a pair of press rolls or belts disposed substantially horizontally. It is a figure showing the specific aspect of the process of shape | molding the said capacitor electrode composition into a sheet-like molded object with a roll or belt, and crimping | bonding this to the roughened surface of the said support body.

In FIG. 1, the roll of the first support 14 is attached to the unwinder 11 and sent out. Next, the capacitor electrode composition (composite particles in the figure) 13 is supplied to a pair of press rolls 12 arranged substantially horizontally by a supply device such as a screw feeder, and is pressure-formed by a pair of press rolls. The capacitor electrode composition is molded into a sheet-like molded body, and this is pressure-bonded to the surface of the first support 14. And the 1st support body in which the capacitor layer was formed is wound up with the winder 10, and the 1st support body and the winding-up body of a capacitor layer are obtained.

The pair of press rolls shown in FIG. 1 can be replaced with a pair of press belts. Moreover, in FIG. 1, although demonstrated as the 1st support body 1 by which the surface was roughened or released, when the 1st support body 1 was changed into the support body in a 1st manufacturing method, It becomes a figure which shows the process in a 1st manufacturing method.

(First support)
The 1st support body used for the 2nd manufacturing method is used in order to support a capacitor layer, when roll forming a capacitor layer. As a material constituting the first support, inorganic materials and organic materials can be used without limitation as long as the capacitor layer can be formed on the first support. For example, metal foil such as aluminum foil and copper foil; plastic film; paper and the like can be mentioned. Moreover, you may use the film of the multilayered structure which accumulated the said film. Among these, paper and thermoplastic resin film are preferable from the viewpoint of versatility and handling, and among paper and thermoplastic resin film, in particular, PET (polyethylene terephthalate) film, polyolefin film, PVA (polyvinyl alcohol) film, PVB (Polyvinyl butyral film) and PVC (polyvinyl chloride) film are preferable.

In the second manufacturing method, the surface of the first support in contact with the capacitor layer is roughened or released. Since the surface of the first support that is in contact with the capacitor layer is roughened, it can be in close contact with the capacitor layer due to the anchoring effect and can be rolled up. Moreover, when manufacturing the lead storage battery electrode, the capacitor layer can be easily transferred from the first support to the second support. The surface roughness Ra of the roughened surface of the first support is determined from the viewpoint of adhesion between the capacitor layer and the first support, and the capacitor layer from the first support to the second support. From the viewpoint of facilitating transfer of the film, it is preferably in the range of 0.1 to 5 μm, more preferably 0.2 to 3 μm, and still more preferably 0.2 to 1 μm.

The surface roughness Ra can be calculated from the equation shown below by drawing a roughness curve using, for example, a nanoscale hybrid microscope (VN-8010, manufactured by Keyence Corporation) in accordance with JIS B0601. In the following formula, L is the measurement length, and x is the deviation from the average line to the measurement curve.

A method for roughening the surface of the first support is not particularly limited, a method for embossing the surface of the first support; a method for sandblasting the surface of the first support; a mat material for the first support And a method of coating a layer containing a mat material on the surface of the first support. Among these, the method of sandblasting the first support surface from the viewpoint of adhesion to the capacitor layer is preferable. The roughening treatment of the first support may be performed only on one side or on both sides.

In the case of releasing the surface of the first support, the method of releasing is not particularly limited. For example, a thermosetting resin such as an alkyd resin is applied on the first support and is cured. Method: It is preferable to use a method in which a silicone resin is coated on a first support and cured, and a method in which a fluororesin is coated on the first support. In particular, from the viewpoint of easily forming a homogeneous release treatment layer, release treatment using a thermosetting resin is preferable, and the moldability of the capacitor layer and the first support to the second support are preferred. From the viewpoint of the balance of ease of transfer of the capacitor layer, a release treatment by coating and curing of an alkyd resin is preferable.

The thickness of the first support is not particularly limited, but is preferably 10 to 200 μm, more preferably 20 to 150 μm, and particularly preferably 20 to 100 μm. The width is not particularly limited, but is preferably 100 to 1000 mm, more preferably 100 to 500 mm.

The tensile strength of the first support is not particularly limited, but is preferably 30 to 500 MPa, more preferably 30 to 300 MPa, from the viewpoint of preventing breakage during the production of the capacitor layer.
The 1st support body used for this invention can also be used repeatedly, and can reduce the production cost of an electrode further by using it repeatedly.

(Capacitor layer)
Hereinafter, the capacitor layer obtained by the first manufacturing method and the second manufacturing method will be described.

The density of the capacitor layer obtained by roll forming is not particularly limited, but is usually 0.30 to 10 g / cm ³ , preferably 0.35 to 5.0 g / cm ³ , more preferably 0.40 to 3.0 g. / Cm ³ . The thickness of the capacitor layer is not particularly limited, but is usually 5 to 1000 μm, preferably 20 to 500 μm, more preferably 30 to 400 μm.

Further, the density of the binder in the capacitor layer obtained by roll forming is 0.45 to 0.52 g / cm ³ on each of the negative electrode side and the positive electrode side when producing a lead capacitor storage battery described later, It is preferably 0.49 to 0.51 g / cm ³ . In the present invention, the binder density in the range of 0.48 to 0.52 g / cm ³ on the positive electrode side and the negative electrode side means that the capacitor layer is positioned at the intermediate point in the thickness direction between the positive electrode side and the negative electrode side. When divided into two regions, the binder density is in the above range on both the positive electrode side and the negative electrode side. When the density of the binder on the positive electrode side or the negative electrode side in the capacitor layer is too large or too small, the resistance of the obtained capacitor electrode for lead storage battery increases. The density of the binder in the capacitor layer is dyed by allowing the binder in the electrode to stand overnight in an osmium environment, and a cross section is cut out from the dyed electrode using a cross section polisher (CP). The cross section cut out using an electron microscope (SEM) can be observed and converted from the result.

Further, the capacitor electrode composition may be heated when being supplied to the pair of press rolls or belts arranged substantially horizontally. The temperature of the capacitor electrode composition at that time is such that there is no slip of the capacitor electrode composition on the surface of the press roll or belt, and the capacitor electrode composition is continuously and uniformly supplied to the press roll or belt. The temperature is preferably 40 to 160 ° C., more preferably 70 to 140 ° C., from the viewpoint of obtaining a capacitor layer having a uniform film thickness and small variation in density.

Further, the temperature at the time of molding in roll molding is usually 25 to 200 ° C., preferably 50 to 150 ° C., more preferably 60 to 120 ° C. from the viewpoint of developing good adhesive force. The molding speed is usually 0.1 to 20 m / min, preferably 4 to 20 m / min.

The press linear pressure between the rolls is usually 10 to 1000 kN / m, preferably 200 to 900 kN / m, more preferably 300 to 600 kN / m from the viewpoint of forming a uniform capacitor layer. Further, the forming speed when using a belt is usually 1 to 15 m / min, preferably 5 to 10 m / min. The pressure between the pressing belts is usually 5 to 50 MPa, preferably 10 to 30 MPa.

In the present invention, post-pressurization may be further performed as necessary in order to eliminate variations in the thickness of the molded capacitor layer and increase the density of the capacitor layer to increase the capacity. The post-pressing method is generally a roll press process. 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.

(Lead capacitor battery)
The lead capacitor storage battery of the present invention includes a positive electrode and a negative electrode, a separator disposed between the positive electrode and the negative electrode, and an electrolytic solution, and is described above at least between the positive electrode and the separator and between the negative electrode and the separator. The capacitor electrode for lead acid battery is arrange | positioned.

A lead capacitor storage battery is usually arranged such that a positive electrode and a negative electrode face each other with a separator interposed therebetween, and the above-mentioned lead storage battery capacitor electrode is arranged between at least one of the positive electrode and the separator and between the negative electrode and the separator. The positive electrodes or the negative electrodes are electrically short-circuited. By setting it as such a structure, the capacity | capacitance of a lead capacitor storage battery can be enlarged.
In the lead capacitor storage battery of the present invention, examples of the constituent elements other than those described above include a battery case and a lid for storing the above constituent elements.

(Positive electrode and negative electrode)
The positive electrode and the negative electrode comprise a lead active material layer. Lead active material layer contains lead and lead compounds such as lead, lead monoxide, lead dioxide, dilead trioxide, trilead tetroxide (lead red), lead sulfate, etc. Refers to the main layer. These lead and lead compounds can be used alone or in a suitable mixture. From the viewpoint of increasing the energy density of the active material layer, the proportion of lead atoms in the lead active material layer is usually 50% by weight or more, preferably 70% by weight or more, based on the weight of the entire layer. The lead-containing material used in the positive electrode active material layer that is the lead active material layer included in the positive electrode is preferably lead dioxide or lead monoxide, and is used in the negative electrode active material layer that is the lead active material layer included in the negative electrode. As the lead-containing material, lead monoxide or lead is preferable.

The lead active material layer may contain a reinforcing material such as polyester fiber, a surfactant such as lignin, barium sulfate and the like in addition to the lead-containing material. Further, an additive selected from oxides, hydroxides or sulfates of antimony, zinc, cadmium, silver and bismuth can be used. Further, when a lead active material layer is formed by producing a paste of a lead-containing material, sulfuric acid can be added.

(Method for forming lead active material layer)
The lead active material layer can be formed by preparing a paste by adding a solvent and an additive to a lead-containing material and filling the paste on a grid-like current collector.

For example, when using a grid current collector, a lead active material layer is formed on a part of the grid plane of the grid current collector, a lead active material layer is formed on the entire grid surface of the grid current collector, and the like. It is done.

(Lamination method of lead active material layer and capacitor layer)
The lead active material layer and the capacitor layer must be electrically connected. Therefore, these layers are preferably pressure bonded. For example, a lead storage battery capacitor electrode is pressure-molded on the lead active material layer filled in the grid-like current collector by the above-described method of forming a lead active material layer.
At this time, it arrange | positions so that the capacitor layer side of the capacitor electrode for lead acid batteries may oppose a lead active material layer, and it pressure-molds.

(Current collector)
The current collector used in the present invention is for establishing electrical continuity between the capacitor electrode active material and the lead-containing material and the outside of the lead storage battery. Examples of the current collector include a plate-shaped, foil-shaped, clad-type porous tube in which a lead alloy core is inserted, and a grid-shaped current collector. Among these, a grid-like current collector is preferable from the viewpoint of maintaining the electrode active material layer and excellent current collecting properties. As the grid current collector, any of a standard grid, a radial grid, and an expanded type can be used.

As the material of the grid current collector, a lead-containing alloy such as a lead-calcium alloy, a lead-antimony alloy, or a lead-tin alloy is used. Arsenic, tin, copper, silver, aluminum, or the like may be included as part of the composition of the lead alloy.

(Separator)
As the separator used in the lead capacitor storage battery of the present invention, one or a combination of separators such as papermaking, microporous polyethylene, microporous polypropylene, microporous rubber, retainer mat, glass mat, etc., should be used. Can do.

(Electrolyte)
The electrolytic solution used in the lead capacitor storage battery of the present invention is usually sulfuric acid. Although the density of sulfuric acid varies depending on the charge / discharge state, the density is preferably 1.25 to 1.30 g / cm ³ (20 ° C.) in a fully charged state after chemical conversion treatment of the lead storage battery.

(Battery, lid)
In the lead capacitor storage battery of the present invention, the positive electrode, the negative electrode, the separator, the capacitor electrode for the lead storage battery, and the battery case and the lid for storing the electrolyte are ethylene-propylene copolymer, polyethylene, polypropylene, polyacrylonitrile-styrene copolymer. In addition, a polyacrylonitrile-butadiene-styrene copolymer as a raw material can be used.

(Battery)
As described above, a plurality of structures in which the positive electrode and the negative electrode are opposed to each other with the separator interposed therebetween, and the above-described lead storage battery capacitor electrode is disposed between at least one of the positive electrode and the separator and between the negative electrode and the separator. A plurality of lead capacitor storage batteries having a structure in which a pair of positive electrodes and negative electrodes are short-circuited can be prepared and connected in series. By doing in this way, the electromotive force of the whole lead capacitor storage battery can be enlarged. There is no need to prepare a plurality of battery cases in order to connect in series. A plurality of partitions are provided in one battery case, and the structure including the above-described positive electrode, negative electrode, separator, and lead-acid battery capacitor electrode is provided for each partition. If it is housed and connected in series, an integrated lead capacitor battery with high electromotive force can be produced.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto. In the examples, parts and% are based on weight unless otherwise specified.

In the examples and comparative examples, the determination of the capacitor electrode layer strength, the adhesion with the lead electrode, the dispersibility of the electrolyte-dispersible cellulose in the electrolyte, the internal resistance, and the input characteristics were performed as follows.

(Capacitor electrode layer strength)
It measured according to JIS K6251. After the capacitor electrode obtained by forming the capacitor electrode layer into a sheet on a support made of electrolyte-dispersible cellulose having a thickness of 25 μm was dried at 160 ° C. for 40 minutes, the shape of No. 1 dumbbell-shaped test piece Then, a tensile test was performed at an atmospheric temperature of 25 ° C. and a tensile speed of 10 mm / min, and the maximum load at break was measured. This measurement was repeated 6 times, and the value obtained by dividing the average value of the maximum load by the cross-sectional area of the sheet was taken as the tensile strength of the capacitor electrode, and evaluated according to the following criteria. The results are shown in Table 1.
It shows that as the tensile strength of the capacitor electrode is larger, cracking and breakage are less likely to occur and the shape retention is better.
A: 0.5 MPa or more B: 0.4 MPa or more and less than 0.5 MPa C: 0.3 MPa or more and less than 0.4 MPa D: Less than 0.3 MPa

(Adhesion with lead electrode)
The capacitor electrode was pressure-bonded to a 1 cm square lead plate at 160 ° C. and 2 MPa for 30 minutes, and the penetration resistance was measured. After measuring for 10 minutes at 10 mA, the volume resistivity was calculated and evaluated by the increase in resistance value with respect to the capacitor electrodes prepared in Examples and Comparative Examples. Evaluation was performed according to the following criteria, and the results are shown in Table 1.
A: 0.1 or more and less than 1 time B: 1 or more and less than 2 times C: 2 or more and less than 5 times D: 5 or more times

(Electrolyte dispersible cellulose dispersible)
In a 200 mL beaker, a support (thickness 25 μm) made of an electrolytic solution-dispersible cellulose, which is a 2 cm square test sample, and 100 mL of 38% sulfuric acid, which is an electrolytic solution, were left for 1 week. The mixture was stirred for 30 seconds with a stirrer and then left for 5 minutes. The degree of dispersion of the test sample was determined according to the following criteria, and the results are shown in Table 1.
A: There is no precipitate, and the electrolyte is transparent or translucent, and no fiber derived from the test piece is observed. B: There is a precipitate, the electrolyte is transparent or translucent, and the thickness of the bottom of the beaker is 1 cm. C: A fiber derived from a piece is observed C: There is a precipitate, the electrolyte is transparent or translucent, and a fiber derived from a test piece having a thickness of 2 cm at the bottom of the beaker is seen D: The test piece remains in shape ing

The amount of the electrolyte-dispersible cellulose relative to 100 parts by weight of the capacitor electrode active material was measured as follows.
A capacitor electrode including a capacitor layer formed into a sheet shape on a support made of electrolyte-dispersible cellulose was punched out to a size of 12φ and immersed in sulfuric acid adjusted to 38% for 1 week. Thereafter, the capacitor electrode was taken out and dried to measure the weight. The amount of change in weight before and after immersion in sulfuric acid was shown as parts by weight relative to 100 parts of the capacitor electrode active material.

(Internal resistance)
The capacitor electrodes obtained in the examples and comparative examples were punched into a circular shape having a diameter of 12 mm, the capacitor electrodes and the glass fiber separator were sufficiently impregnated with the electrolyte, and then the two capacitor electrodes were opposed to each other through the separator. Then, each capacitor electrode was arranged so as not to be in electrical contact, and an electric double layer capacitor was manufactured. Sulfuric acid was used as the electrolyte.

The internal resistance was determined by conducting a charge / discharge test of the electric double layer capacitor. That is, the charging current is performed using a current value at which the current value per unit area of the electrode is 6.6 mA / cm ^2, and when the voltage reaches 1.0 V, the voltage is maintained for 10 minutes for constant voltage charging. Completed charging. Then, immediately after the end of charging, constant current discharging is performed until the voltage reaches 0 V at a current value similar to that used during charging. The capacitance was calculated from the amount of electric power at the time of discharge using an energy conversion method.

Next, using this capacitance, charging is started at a constant current of 5 mA / F so that the charging / discharging speed of the electric double layer capacitor is constant, and the charging times of constant current charging and constant voltage charging are matched. Charging was completed at the time when the charging was performed for 20 minutes, and further, constant current discharging was performed immediately after the end of charging until the voltage reached 0 V at a current value similar to that used during charging.

The internal resistance is a value obtained by dividing the amount of voltage drop at the start of discharge from the extrapolation of the approximate curve by the least square method of the voltage data from the start of discharge to the predetermined time divided by the discharge current value, and the resistivity per volume, that is, the volume Expressed as resistivity and evaluated according to the following criteria. However, the predetermined time was 10% of the total discharge time. The results are shown in Table 1.
A: Less than 0.6Ω B: 0.6 or more and less than 0.8Ω C: 0.8 or more and 1.0Ω or more D: 1.0Ω or more

(Input characteristics)
When the lead capacitor storage battery obtained in the example and the comparative example is charged at 10 CA from the last discharge state by repeating the operation of charging / discharging the lead capacitor storage battery obtained at 25 ° C. with a current of 2 CA from a charging voltage of 2.2 V to SOC 70%. The voltage after 0.2 seconds was measured. The difference from the voltage immediately before discharging at 10 CA was expressed as a relative value with respect to the example and the comparative example as the input characteristics after the cycle, and evaluated according to the following criteria. The results are shown in Table 1.

Note that SOC 70% refers to a state in which the capacity of the lead storage battery is 100% and the capacity of 70% remains. 2CA and 10CA are the capacity of the produced storage battery for 1/2 hour, It refers to the amount of current for discharging in 1/10 hours. The smaller the voltage value difference, the better the acceptance of large current charging.
A: 100 or more and less than 110% B: 110 or more and less than 120% C: 120 or more and less than 130% D: 130% or more

(Example 1)
(Preparation of binder)
In a nitrogen-substituted polymerization reactor, acrylonitrile (AN) 45 parts, 1,3-butadiene (BD) 50 parts, methacrylic acid (MMA) 5 parts, t-dodecyl mercaptan (TDM) 0.2 parts, soft water 132 parts, 3.0 parts of sodium dodecylbenzenesulfonate, 0.5 part of β-naphthalenesulfonic acid formalin condensate sodium salt, 0.3 part of potassium persulfate and 0.05 part of ethylenediaminetetraacetic acid sodium salt were charged, and the polymerization temperature was 40 ° C. While maintaining, the reaction was continued until the polymerization conversion reached 90%. Thereafter, 0.1 part of sodium dimethyldithiocarbamate was added as a polymerization terminator to terminate the polymerization reaction. After removing unreacted monomers from the obtained copolymer particle aqueous dispersion, the pH and solid content concentration of the copolymer particle water dispersion station are adjusted to obtain a copolymer having a solid content concentration of 40% and pH of 8. An aqueous particle dispersion was obtained. The obtained copolymer particle aqueous dispersion was stored for one week, and then BIT (1,2-benz-2-methyl-4-isothiazolin-3-one) as a preservative was solidified in the copolymer particle aqueous dispersion. 0.2 part was added to 100 parts per minute and stirred to obtain Binder A (NBR1). Binder A had a Tg of −20 ° C. and a volume average particle size of 100 nm.

(Production of composite particles)
100 parts of petroleum pitch-derived high-purity activated carbon powder having a specific surface area of 2,200 m ² / g and a weight average particle diameter of 5 μm as a capacitor electrode active material, and acetylene black (trade name “DENKA BLACK POWDER”: Electric 5 parts by chemical industry), 1.5 parts aqueous solution of carboxymethyl cellulose (trade name “WS-C”: manufactured by Daicel Chemical Industries, Ltd.) as electrolyte-insoluble cellulose in an amount equivalent to 1.4 parts by solid content Then, the binder A as a binder was mixed in an amount of 9 parts in terms of solid content, and ion-exchanged water was further added so that the solid content concentration was 20%, followed by mixing and dispersion to obtain a slurry. This slurry is spray-dried using a spray dryer (Okawara Chemical Co., Ltd.) at a rotational speed of 25,000 rpm of a rotating disk type atomizer (diameter 65 mm), a hot air temperature of 150 ° C., and a particle recovery outlet temperature of 90 ° C. Granulation was performed to obtain spherical composite particles. The spherical composite particles had an average volume particle size of 63 μm.

(Production of capacitor electrodes for lead-acid batteries)
The obtained spherical composite particles were sprayed on a roughened surface of a roughened PET film (surface roughness Ra = 0.3 μm) and heated to 65 ° C. (molding speed 20 m / m). Sheet forming was performed at a press linear pressure of 5.0 kN / cm (500 kN / m)) to obtain a capacitor layer having a thickness of 200 μm and a density of 0.54 g / cm ³ . Further, the density of the binder in the capacitor layer was 0.5 g / cm ³ on each of the negative electrode side and the positive electrode side when a lead capacitor storage battery described later was manufactured.

Furthermore, the obtained capacitor layer is transferred onto a support (thickness 25 μm) made of electrolyte-dispersible cellulose (short fibers: length 1 to 2 mm, width 20 μm) to obtain a capacitor electrode for a lead storage battery. It was. Note that the lead storage battery capacitor electrode does not include a PET film.

(Preparation of negative electrode)
As a lead-containing material, a paste was obtained by adding and mixing 100 parts of lead oxide with 0.3 parts of conductive agent carbon black, 0.3 parts of barium sulfate, 10 parts of ion-exchanged water, and 10 parts of diluted sulfuric acid with a specific gravity of 1.36. . The obtained paste was filled in a grid-like current collector (100 mm × 100 mm × 3 mm) made of a lead-calcium alloy to produce a negative electrode.

(Lamination of negative electrode and capacitor electrode for lead acid battery)
The capacitor electrode for a lead storage battery was pressure-bonded at 100 ° C. and 2 MPa with a batch press on one surface of the negative electrode filled with the paste in a grid-like current collector.

As described above, the negative electrode and the capacitor electrode for the lead storage battery were laminated by press-molding the capacitor electrode for the lead storage battery on the negative electrode. At this time, the lead-acid battery capacitor electrode was pressure-molded with the capacitor layer side facing the current collector side of the negative electrode.

(Preparation of positive electrode)
As a lead-containing material, 10 parts of ion-exchanged water and 10 parts of dilute sulfuric acid having a specific gravity of 1.27 were added to 100 parts of lead oxide and mixed to produce a positive electrode active material mixture paste. After filling this paste into a grid-like current collector (100 mm × 100 mm × 3 mm) made of lead-calcium alloy, the paste was aged in an atmosphere of 40 ° C. and 95% humidity for 24 hours and dried to form an unformed positive electrode. Produced.

(Production of lead capacitor battery)
A multilayer lead capacitor storage battery shown in FIG. 2 was produced using the positive electrode, the stacked negative electrode, and the capacitor electrode for a lead storage battery. As the separator, a glass microfiber separator 5 is disposed between the negative electrode 2 and the positive electrode 4, and a microporous polypropylene separator 6 is disposed between the lead storage battery capacitor electrode 3 and the positive electrode 4. did. In FIG. 2, 1 indicates a current collector.

As the electrolyte, dilute sulfuric acid having a specific gravity of 1.225 (20 ° C.) was used. After subjected to overcharge chemical conversion process to this, the density of the electrolyte solution to obtain a lead-capacitor battery is adjusted with sulfuric acid of density 1.4 g / cm ³ so that the 1.28 g / cm ^3. Further, the amount of the electrolyte-dispersible cellulose in the electrolyte with respect to 100 parts of the capacitor electrode active material was 25 parts.

(Example 2)
Capacitor electrode for lead-acid battery, lead as in Example 1, except that activated carbon derived from phenol resin (specific surface area 1700 m ² / g, weight average particle size 5 μm) was used instead of the capacitor electrode active material derived from petroleum pitch A capacitor storage battery was produced.

(Example 3)
Capacitor electrode for lead-acid battery, lead as in Example 1, except that activated carbon derived from coconut shell (specific surface area 2000 m ² / g, weight average particle diameter 5 μm) was used instead of the capacitor electrode active material derived from petroleum pitch A capacitor storage battery was produced.

Example 4
Binder B (SBR) was obtained by using styrene (ST) instead of acrylonitrile when preparing the binder. The binder B had a Tg of −20 ° C. and a volume average particle size of 100 nm. A lead-acid battery capacitor electrode and a lead-capacitor battery were produced in the same manner as in Example 1 except that the binder B was used when producing the composite particles.

(Example 5)
Binder C (NBR2) was obtained by using 63 parts of acrylonitrile, 32 parts of 1,3-butadiene, and 5 parts of methacrylic acid as the composition of the monomer used in preparing the binder. The binder C had a Tg of 14 ° C. and a volume average particle size of 100 nm. A capacitor electrode for a lead storage battery and a lead capacitor storage battery were prepared in the same manner as in Example 1 except that the binder C was used when preparing the composite particles.

(Example 6)
Binder D (NBR3) was obtained by using 35 parts of acrylonitrile, 55 parts of 1,3-butadiene, and 10 parts of methacrylic acid as the composition of the monomer used in preparing the binder. The binder D had a Tg of −26 ° C. and a volume average particle size of 100 nm. A lead-acid battery capacitor electrode and a lead-capacitor battery were produced in the same manner as in Example 1 except that the binder D was used when producing the composite particles.

(Example 7)
A lead-acid battery capacitor as in Example 1 except that a support made of electrolyte-dispersible cellulose was used so that the amount of electrolyte-dispersible cellulose in the electrolyte with respect to 100 parts of the capacitor electrode active material was 10 parts. Electrodes and lead capacitor storage batteries were produced. In addition, adjustment of the quantity of electrolyte solution dispersible cellulose was performed by changing the fiber diameter of the electrolyte solution dispersible cellulose which comprises a support body.

(Example 8)
A lead-acid battery capacitor as in Example 1 except that a support made of electrolyte-dispersible cellulose was used so that the amount of electrolyte-dispersible cellulose in the electrolyte was 30 parts with respect to 100 parts of the capacitor electrode active material. Electrodes and lead capacitor storage batteries were produced. In addition, adjustment of the quantity of electrolyte solution dispersible cellulose was performed by changing the fiber diameter of the electrolyte solution dispersible cellulose which comprises a support body.

Example 9
In the production of a lead-acid battery capacitor electrode, the obtained spherical composite particles were dispersed on a support made of electrolyte-dispersed cellulose having a thickness of 25 μm and heated to 65 ° C. (molding speed 10 m / min, The sheet was molded at a press linear pressure of 5.0 kN / cm), and the same as in Example 1 except that a capacitor electrode for a lead storage battery having a capacitor layer with a thickness of 200 μm and a density of 0.54 g / cm ³ was obtained. A capacitor electrode for a lead storage battery and a lead capacitor storage battery were produced.

(Comparative Example 1)
Instead of roll forming in preparation of composite particles and lead storage battery capacitor electrode, cast slurry containing binder A (slurry used for manufacture of composite particles in Example 1) on electrolyte-dispersible cellulose, A capacitor electrode for a lead storage battery and a lead capacitor storage battery were prepared in the same manner as in Example 1 except that the capacitor electrode for a lead storage battery was obtained by drying at 100 ° C. The density of the binder in the capacitor layer was 0.35 g / cm ³ on each of the negative electrode side and the positive electrode side.

(Comparative Example 2)
A capacitor electrode for a lead storage battery and a lead capacitor storage battery were prepared in the same manner as in Comparative Example 1 except that the drying temperature after casting the slurry containing the binder A onto the electrolyte-dispersible cellulose was 60 ° C. The density of the binder in the capacitor layer was 0.45 g / cm ³ on each of the negative electrode side and the positive electrode side.

(Comparative Example 3)
A capacitor electrode for a lead storage battery and a lead capacitor storage battery were prepared in the same manner as in Example 1 except that the capacitor layer was directly transferred to the negative electrode and then the PET film was peeled to laminate the negative electrode and the capacitor layer. It was.

(Comparative Example 4)
A lead-acid battery capacitor electrode and a lead-capacitor battery were prepared in the same manner as in Example 1 except that electrolyte-insoluble paper was used instead of the electrolyte-dispersible cellulose.

As shown in Table 1, a capacitor electrode for a lead storage battery that is disposed between a negative electrode and a positive electrode and includes a capacitor layer, the capacitor layer including a capacitor electrode active material, a conductive agent, and a binder, The binder density of the layer is in the range of 0.48 to 0.52 g / cm ³ on the positive electrode side and the negative electrode side, and when the electrolytic solution-dispersible cellulose compound is dispersed in the electrolytic solution, The adhesiveness with the lead electrode, electrolyte dispersibility, cellulose dispersibility, internal resistance, and input characteristics were all good.

Claims

A capacitor electrode for a lead storage battery, which is disposed between a negative electrode and a positive electrode and includes a capacitor layer,
The capacitor layer includes a capacitor electrode active material, a conductive agent and a binder,
The binder density of the capacitor layer is in the range of 0.48 to 0.52 g / cm 3 on the positive electrode side and the negative electrode side,
A capacitor electrode for a lead storage battery comprising an electrolytic solution-dispersible cellulose compound dispersed in an electrolytic solution.
The lead-acid battery capacitor electrode according to claim 1, wherein the capacitor layer contains an electrolyte-insoluble cellulose.
The lead-acid battery capacitor electrode according to claim 2, wherein a ratio of the electrolyte-insoluble cellulose in the capacitor layer is 0.1 to 10 parts by weight with respect to 100 parts by weight of the capacitor electrode active material.
The lead-acid battery capacitor electrode according to any one of claims 1 to 3, wherein the capacitor electrode active material is activated carbon starting from petroleum pitch.
The lead-acid battery capacitor electrode according to any one of claims 1 to 4, wherein the binder is a diene polymer.
A lead capacitor storage battery comprising the capacitor electrode for a lead storage battery according to any one of claims 1 to 5, a negative electrode, a positive electrode, a separator, and an electrolytic solution.
A step of granulating composite particles comprising a capacitor electrode active material, a conductive agent and a binder;
A method for producing a capacitor electrode for a lead storage battery, comprising: forming a capacitor layer containing the composite particles on a support made of an electrolyte-dispersible cellulose by a dry method.
The sheet forming step supplies the composite particles and a support made of an electrolyte-dispersible cellulose to a pair of press rolls or belts arranged substantially horizontally, and the pair of press rolls or belts In addition, a capacitor layer is obtained by molding the composite particles into a sheet-like molded body, and this is a step of pressure-bonding this to the surface of the support.
The manufacturing method of the capacitor electrode for lead acid batteries of Claim 7.
A step of granulating composite particles comprising a capacitor electrode active material, a conductive agent and a binder;
Forming a capacitor layer containing the composite particles on a roughened or release-treated support surface;
And transferring the capacitor layer onto a support made of an electrolyte-dispersible cellulose.
The step of forming the capacitor layer includes supplying the composite particles and a roughened or release-treated support to a pair of pressing rolls or belts arranged substantially horizontally, A step of forming a capacitor layer by molding the composite particles into a sheet-like molded body with a roll or a belt, and crimping the capacitor layer to the surface of the support.
The manufacturing method of the capacitor electrode for lead acid batteries of Claim 9.
A method for producing a lead capacitor storage battery, comprising the step of laminating a lead storage battery capacitor electrode and a lead active material layer obtained by the method for producing a lead capacitor storage battery according to any one of claims 7 to 10.