JP4034569B2 - Method for producing electrode material for electric double layer capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an electric double-layer capacitor electrode material capable of being manufactured with reproducibility an electrode material with high energy density, a uniformly small thickness, and the concise stable quality. <P>SOLUTION: A method for manufacturing an electric double-layer capacitor electrode material comprises a first step, a second step and a third step: wherein the first step, an active carbon, an acetylene black, an aggregate of ultra-thin fibers having a fiber diameter 5 &mu;m or smaller, and an aggregate of a pulp-like substance are spouted in a gas from a nozzle by an action of a compressed gas, and the active carbon and the acetylene black are dispersed, and further the ultra-fibers and the pulp-like substance are generated and dispersed; in the second step, the dispersed active carbon, the acetylene black, the ultra-thin fibers and the pulp-like substance are accumulated to form an active carbon included aggregate; and in the third step, the active carbon and the acetylene black are fixed by welding of the ultra-thin fibers of the active carbon included aggregate, to form the electric double-layer capacitor electrode material. <P>COPYRIGHT: (C)2003,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an electrode material for an electric double layer capacitor.
[0002]
[Prior art]
Development of electric double layer capacitors that can store a large amount of energy and have a long life is being actively carried out. In particular, with regard to the electrode material of the electric double layer capacitor, active research has been actively conducted focusing on activated carbon in order to realize low internal resistance and high output density.
[0003]
In order to use the selected member centering on the powder as the electrode material, it is necessary to process it so as to be suitable for use. As this processing method, conventionally, a method of applying a selected powder member to a separately prepared current collector (coating method), a powder of polytetrafluoroethylene and a selected powder member (activated carbon, acetylene black) are kneaded. After preparing mixed particles entangled with powder members (activated carbon, acetylene black) by fibrils of polytetrafluoroethylene powder generated by friction between powders, this mixed particle is compacted with a molding die There is known a method of forming (molding method), or a method of further kneading the mixed particles and rolling them with a two-roll mill to form a sheet (rolling method).
[0004]
The coating method has good productivity and is suitable for producing a thin electrode material having a thickness of 100 μm or less, but has a problem that the energy density cannot be increased. Further, the molding method is a method in which a large energy density can be obtained, but a thin electrode material cannot be mass-produced uniformly. Furthermore, although the rolling method is located between the coating method and the molding method, there has been a problem that the kneading of the powder member is complicated, and it is difficult to produce an electrode material with stable quality with good reproducibility.
[0005]
[Problems to be solved by the invention]
The present invention has been made in order to solve the above-mentioned problems, and it is possible to produce an electrode material having a high energy density, a thin and uniform thickness, and a simple and stable quality with high reproducibility. An object of the present invention is to provide a method for producing an electrode material for an electric double layer capacitor.
[0006]
[Means for Solving the Problems]
The method for producing an electrode material for an electric double layer capacitor of the present invention (hereinafter sometimes simply referred to as “electrode material”) is “active carbon, acetylene black, an aggregate of ultrafine fibers having a fiber diameter of 5 μm or less, compression An assembly of separable fibers that can be divided into ultrafine fibers having a fiber diameter of 5 μm or less by the action of gas, an aggregate of pulp-like materials, and an aggregate of split fibers that can be fibrillated into pulp by the action of compressed gas At least one aggregate selected from the inside is ejected from the nozzle into the gas by the action of the compressed gas to disperse the activated carbon and acetylene black, and the aggregate The Extra fine fiber and / or pulp As A step of dispersing, a step of accumulating the dispersed activated carbon, acetylene black, ultrafine fibers and / or pulp-like material to form an activated carbon-containing aggregate, activated carbon and / or pulp-like aggregates of activated carbon and aggregates; A process for producing an electrode material for an electric double layer capacitor by fixing acetylene black ”. As described above, the method for producing an electrode material of the present invention can uniformly mix and disperse activated carbon, acetylene black, and aggregate by ejecting them from the nozzle into the gas by the action of the compressed gas. Can be manufactured. In this method for producing an electrode material, the thickness can be freely adjusted by the step of fixing the activated carbon and acetylene black with ultrafine fibers and / or pulp-like materials, so that the thickness can be easily reduced. Further, since the basis weight can be easily adjusted by adjusting the amount of the raw material to be supplied (activated carbon, acetylene black, aggregate), an intended electrode material having a high energy density can be produced. Furthermore, since it can be uniformly mixed just by jetting and dispersing in the gas by the action of the compressed gas, a complicated kneading operation is unnecessary, and an electrode material with stable quality can be produced continuously. This is a method for producing an electrode material with excellent productivity.
[0007]
When the fixing step is a step of fixing activated carbon and acetylene black by fusing ultrafine fibers, the dimensions of the electrode material can be stabilized and the uniformity can be maintained, so that variations in energy density are reduced. In addition, it is difficult for the powder to fall off which causes a short circuit of the electric double layer capacitor. In particular, since acetylene black has small particles and is submicron or smaller, if it is desorbed in an electric double layer capacitor, it floats in the electrolyte and tends to enter the separator and cause a short circuit. When fixed by fusion, such a micro short circuit is unlikely to occur.
[0008]
When the pulp-like material is made of a resin selected from wholly aromatic polyamide resin, polyimide resin, and polybenzimidazole resin, the electrode material itself has high heat resistance, so that it can be dried at a high temperature and constitutes an electric double layer capacitor. When the electrolytic solution to be used is an organic solvent, it is effective for removing moisture. In other words, if there is moisture, gas is generated by electrolysis when the voltage is increased, and the electric double layer capacitor breaks or induces a chemical reaction, resulting in a variation in performance. Therefore, such an adverse effect can be avoided. Moreover, since the pulp-like material can maintain the shape even if the ultrafine fibers are fused, stable production is possible.
[0009]
When blended so that the mass ratio of (activated carbon) to (acetylene black) to (aggregate) is 6 to 8: 2 to 1: 2 to 1, an electrode material having excellent electrical conductivity and high energy density is produced. can do.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The activated carbon used in the method for producing an electrode material of the present invention is not particularly limited as long as it has a large surface area, a predetermined pore structure, and a porous structure that can ensure electric double layer capacity. However, for example, coconut shells, petroleum pitch, petroleum coke, phenol resin, etc., which are raw materials, are carbonized at a low temperature of 300 to 700 ° C., then steam, carbon monoxide, oxygen, zinc chloride, calcium chloride, potassium chloride, water Activated carbon activated by using potassium oxide or the like and made porous can be used. The surface area of activated carbon is 1500m. ² / G or more, and the average particle size is preferably 1 to 200 μm. If the average particle size is less than 1 μm, the density of the electrode material becomes too dense and the number of voids that can hold the electrolytic solution decreases. As a result, the resistance increases and the capacity is difficult to be produced, and when the average particle size exceeds 200 μm, the voids become large. This is because the activated carbon that can be filled in the volume of the prescribed electrode material becomes too thin, and the capacity is not easily obtained. “Surface area” refers to a value measured by a nitrogen adsorption method, and “average particle diameter” refers to an average particle diameter measured by a laser diffraction / scattering method.
[0011]
In addition to the activated carbon, acetylene black is used as a conductive filler. Since the activated carbon has a large number of pores, the electrical conductivity is low, and the activated carbon alone cannot be used as an electrode material. Therefore, it is necessary to add and mix a conductive filler. Use acetylene black.
[0012]
In the method for producing an electrode material of the present invention, in addition to the activated carbon and acetylene black, an aggregate capable of generating ultrafine fibers or pulp-like material is used so that the form of the electrode material can be maintained. As aggregates, aggregates of ultrafine fibers having a fiber diameter of 5 μm or less, aggregates of splittable fibers that can be divided into ultrafine fibers having a fiber diameter of 5 μm or less by the action of compressed gas, aggregates of pulp-like materials, compressed gas As an example, there can be mentioned an aggregate of separable fibers that can be fibrillated into pulp.
[0013]
The aggregate of ultrafine fibers is composed of aggregates of ultrafine fibers having a fiber diameter of 5 μm or less so that the retention of activated carbon and acetylene black powder is excellent. The smaller the fiber diameter of the ultrafine fiber, the better the retention of the activated carbon and acetylene black powder, and the smaller the particle diameter of the activated carbon and acetylene black powder can be retained, so the fiber diameter of the ultrafine fiber is 4 μm or less. It is preferably 3 μm or less, more preferably 2 μm or less. In addition, the lower limit of the fiber diameter of the ultrafine fiber is not particularly limited, but about 0.01 μm is appropriate. “Fiber diameter” in the present invention refers to the diameter when the cross-sectional shape of the fiber is circular, and when the cross-sectional shape of the fiber is non-circular, the diameter of the circle having the same cross-sectional area and area is used as the fiber. Consider diameter.
[0014]
The fiber length of the ultrafine fiber is preferably 5 mm or less, and more preferably 3 mm or less so as to be excellent in uniform dispersibility. In addition, although the minimum of the fiber length of an ultrafine fiber is not specifically limited, about 0.1 mm is suitable. Moreover, it is preferable that it is the cut | disconnected ultra fine fiber so that fiber length may be uniform. The “fiber length” in the present invention refers to the length obtained by JIS L 1015 (chemical fiber staple test method) B method (corrected staple diagram method).
[0015]
The components constituting this ultrafine fiber are not particularly limited. For example, polyester resins, polyacrylonitrile resins, polyolefin resins (for example, polyethylene resins, polypropylene resins, polymethylpentene resins, etc.), all Organic components such as aromatic polyamide resin, polyimide resin, polyphenylene sulfide resin, wholly aromatic polyester resin, polybenzoxazole resin, glass, carbon, potassium titanate, silicon carbide, silicon nitride, zinc oxide, boron It can be composed of inorganic components such as aluminum acid and wollastonite. Among these, polyethylene terephthalate is preferably composed of an organic component so as to have excellent dimensional stability and flexibility of the electrode material, and has excellent affinity with the electrolyte solution constituting the electric double layer capacitor. When the electrolytic solution constituting the electric double layer capacitor is an organic solvent, it is made of a polyolefin resin such as polyethylene, polypropylene, polymethylpentene, etc. More preferred. The ultrafine fiber may be composed of these components alone or may be composed of two or more components. Further, two or more types of ultrafine fibers that are different in terms of fiber diameter, components, or fusibility or pressure-bonding properties may be included.
[0016]
If the ultrafine fibers can be fused or crimped, the retention of activated carbon and acetylene black can be enhanced by the fusion or crimping of the ultrafine fibers, and the powder of activated carbon and acetylene black is less likely to fall off. Is preferred.
[0017]
Examples of the ultrafine fibers that can be fused include ultrafine fibers in which at least a part of the components constituting the ultrafine fiber surface is made of a thermoplastic resin. Examples of the thermoplastic resin include polyolefin resins (for example, polyethylene resins, polypropylene resins, etc.), polyester resins, and the like. Among these, from relatively low melting point polyethylene resins and polyester resins. Preferably it is. In addition, it is preferable that the ultrafine fiber is composed of two or more types of components because even if one type of component is fused, the fiber form can be maintained by at least one type of component. The cross-sectional shape of the ultrafine fibers composed of these two or more components can be, for example, a core-sheath type, an eccentric type, a sea-island type, a side-by-side type, a multiple bimetal type, an orange type, and a fusion property. The core-sheath type, the eccentric type, and the sea-island type are preferable.
[0018]
On the other hand, examples of the ultrafine fibers that can be crimped include unstretched ultrafine fibers that have not been sufficiently stretched after spinning. For example, unstretched polyester ultrafine fibers can be used.
[0019]
Moreover, it is preferable that the diameters of the ultrafine fibers are substantially the same in the fiber axis direction so that an electrode material having excellent uniformity can be produced. As described above, the ultrafine fibers having substantially the same diameter in the fiber axis direction are, for example, sea island type fibers manufactured by a composite spinning method in which the base component is regulated into the sea component at the spinneret portion and the island component is extruded to be combined. It can be obtained by removing sea components.
[0020]
The aggregate of the ultrafine fibers of the present invention is a collection of the ultrafine fibers as described above, and the number thereof is not particularly limited. Further, the aggregated state is not particularly limited, and examples thereof include a bundle state in which ultrafine fibers are regularly aligned in a certain direction, and an aggregated state in which they are randomly aligned. Among these, the bundle state is preferable because of excellent dispersibility due to the action of the compressed gas described later.
[0021]
As this ultrafine fiber aggregate, aggregates of different types of ultrafine fibers may be used in combination.
[0022]
The ultrafine fiber assembly of the present invention generates, for example, ultrafine fibers composed of island components by removing the sea components of the sea-island type fibers produced by the composite spinning method or the mixed spinning method, or is spun by the super draw method. It can be manufactured by the method. For ultra-fine fibers consisting of two or more components, supply the resin so that the island component becomes two or more components when spinning the sea-island type fiber, or supply two or more components when spinning by the super draw method Can be manufactured. Further, a bundled ultrafine fiber assembly that is suitable can be obtained by removing sea components of sea-island fibers produced by a composite spinning method or a mixed spinning method.
[0023]
Next, an assembly of splittable fibers that can be divided into ultrafine fibers by the action of compressed gas is also made from splittable fibers so as to have excellent retention of activated carbon and acetylene black, similar to the ultrafine fiber assemblies described above. The fiber diameter of the generated ultrafine fiber (hereinafter referred to as “generated ultrafine fiber”) needs to be 5 μm or less, and the smaller the fiber diameter of the generated ultrafine fiber, the better the retention of activated carbon and acetylene black, Since the activated carbon and acetylene black having a smaller particle diameter can be retained, the fiber diameter of the generated ultrafine fiber is preferably 4 μm or less, more preferably 3 μm or less, and even more preferably 2 μm or less. The lower limit of the fiber diameter of the generated ultrafine fibers is not particularly limited, but about 0.01 μm is appropriate.
[0024]
The fiber length of the generated ultrafine fibers is preferably 5 mm or less, more preferably 3 mm or less so that the uniform dispersibility is excellent. In addition, the lower limit of the fiber length of the generated ultrafine fiber is not particularly limited, but about 0.1 mm is appropriate. Moreover, it is preferable that it is the generation | occurrence | production ultrafine fiber cut | disconnected so that fiber length may be uniform. That is, it is preferable that the generated ultrafine fiber generated from the cut splittable fiber.
[0025]
The component constituting the generated ultrafine fiber is not particularly limited, but can be composed of the same component as the above-described ultrafine fiber, and preferably composed of an organic component for the same reason, Polyethylene resins such as polyethylene terephthalate, polyethylene terephthalate, etc., and polyolefins such as polyethylene, polypropylene, polymethylpentene, etc. The generated ultrafine fibers composed of a resin are more preferable. This generated ultrafine fiber may also be composed of a single component, or may be composed of two or more components. Further, the generated ultrafine fibers may include two or more types of generated ultrafine fibers that are different from each other in terms of fiber diameter, components, or fusibility. Note that it is preferable that the generated ultrafine fibers can be fused, because the retention of the activated carbon and acetylene black can be enhanced by the fusion of the generated ultrafine fibers, and the activated carbon and acetylene black are unlikely to fall off.
[0026]
Examples of the generated ultrafine fibers that can be fused include generated ultrafine fibers in which at least a part of the components constituting the generated ultrafine fiber surface is made of a thermoplastic resin. Examples of the thermoplastic resin include polyolefin resins (for example, polyethylene resins, polypropylene resins, etc.), polyester resins, and the like. Among these, polyethylene resins and polyester resins having a relatively low melting point are used. Is preferred. In addition, it is preferable that the generated ultrafine fiber is composed of two or more types of components because even if one type of component is fused, the fiber form can be maintained by at least one type of component. The cross-sectional shape of the generated ultrafine fibers composed of two or more components can be, for example, a core-sheath type, an eccentric type, a sea-island type, a side-by-side type, a multiple bimetal type, an orange type, The core-sheath type, the eccentric type, and the sea-island type are preferable because of their excellent properties.
[0027]
In addition, it is preferable that the generated ultrafine fibers have substantially the same diameter in the fiber axis direction so that an electrode material with excellent texture can be produced. The generated ultrafine fibers having substantially the same diameter in the fiber axis direction are obtained by, for example, dividing a split fiber manufactured by a composite spinning method in which two or more kinds of components are extruded after being regulated by a die. Obtainable.
[0028]
Examples of splittable fibers that can be divided into such generated ultrafine fibers include fibers produced by a composite spinning method in which two or more types of resin components are extruded and then combined. The lower the compatibility between the two or more types of resin components, the more likely the generated split fibers are generated, and the higher the compatibility, the partly fibrillated as described below, resulting in a pulp-like splitting fiber. In other words, when it is actually ejected from the nozzle into the gas by the action of the compressed gas, it is a split fiber if it is completely split to generate the generated ultrafine fiber, and is it incompletely split into a pulp-like material? In the case of fibrillation like this, it is a split fiber. More specifically, a combination of a polyamide resin and a polyester resin, a combination of a polyamide resin and a polyolefin resin, and a combination of a polyester resin and a polyolefin resin are highly likely to be split fibers, If it is a combination of a polyethylene resin and a polypropylene resin, there is a high possibility that it is a split fiber.
[0029]
The cross-sectional shape of such a splittable fiber can be, for example, orange or multiple bimetal.
[0030]
Such an assembly of split fibers is a collection of split fibers as described above, and the number thereof is not particularly limited. Further, the aggregation state is not particularly limited, and examples thereof include a regularly oriented state and a randomly oriented agglomerated state.
[0031]
This aggregate of splittable fibers may be used in combination with a set of different types of splittable fibers.
[0032]
The aggregate of splittable fibers of the present invention can be obtained, for example, by converging after spinning by a conventional composite spinning method.
[0033]
Next, the aggregate of pulp-like materials is also excellent in retention of activated carbon and acetylene black due to the fibrils of the pulp-like materials. In addition, this pulp-like thing can make the thickness of an electrode material thin and is excellent in uniform dispersibility. Moreover, since the activated carbon and acetylene black retainability by pulp-like fibrils are excellent, the amount of constituent materials of the electrode material can be reduced, and the energy density can be increased. Furthermore, the shape retention is excellent due to the entanglement between the fibrils of the pulp-like material.
[0034]
Although this pulp-like material may be comprised from what kind of resin component, it is preferable to consist of resin chosen from meta type | system | group or para type | system | group fully aromatic polyamide resin, a polyimide resin, and a polybenzimidazole resin. Since such a resin is excellent in heat resistance, the heat resistance of the electrode material itself can be increased, and moisture can be removed by high-temperature drying. In other words, when the electrolytic solution that constitutes the electric double layer capacitor is an organic solvent, if there is moisture, it will be electrolyzed and gas will be generated when the voltage is increased. However, such a harmful effect can be avoided because the moisture can be sufficiently removed by drying at a high temperature. Moreover, since the pulp-like material can maintain the shape even if the ultrafine fibers are fused, stable production is possible.
[0035]
This aggregate of pulp-like materials may be used in combination with an aggregate of different types of pulp-like materials.
[0036]
And, the aggregate of the split fibers that can be fibrillated by the action of the compressed gas is also excellent in the retention of activated carbon and acetylene black by the fibrils, and the thickness of the electrode material can be increased. Can be thin and has excellent uniform dispersibility. Moreover, since the amount of the constituent material of the electrode material can be reduced, the energy density of the electrode material can be increased. Furthermore, it has excellent shape retention due to entanglement with fibrils.
[0037]
Although the component which comprises the pulp-like thing generate | occur | produced from this splitting fiber (henceforth "generated pulp-like thing") is not specifically limited, It can comprise from the component similar to the above-mentioned ultrafine fiber, For the same reason, it is preferably composed of an organic component. In the case where the polyester resin such as polyethylene terephthalate having excellent affinity with the electrolytic solution or the electrolytic solution constituting the electric double layer capacitor is an organic solvent. It is preferably composed of a polyolefin-based resin such as polyethylene, polypropylene, polymethylpentene and the like that is not easily attacked by the electrolytic solution.
[0038]
This generated pulp-like product may be composed of a single component or may be composed of two or more components. Further, two or more kinds of generated pulp-like materials that differ from each other in terms of components and fusibility may be included. Note that it is preferable that the generated pulp-like material can be fused, because the retention of the activated carbon and acetylene black can be enhanced by the fusion of the generated pulp-like material, and the activated carbon and acetylene black are less likely to fall off.
[0039]
An example of the fusible generated pulp-like material is a pulp-like material in which at least a part of the components constituting the surface of the generated pulp-like material is composed of a thermoplastic resin. Examples of the thermoplastic resin include polyolefin resins (for example, polyethylene resins, polypropylene resins, etc.), polyester resins, and the like. Among these, from relatively low melting point polyethylene resins and polyester resins. Preferably it is. Note that it is preferable that the generated pulp-like material is composed of two or more types of components because even if one type of component is fused, the pulp-like form can be maintained by at least one type of component.
[0040]
Examples of the splitting fibers that can be fibrillated into the generated pulp-like material include fibers produced by a composite spinning method in which two or more kinds of resin components are extruded and then combined. The higher the compatibility between the two or more types of resin components, the higher the possibility of being a split fiber. For example, a composite fiber made of a combination of a polyethylene resin and a polypropylene resin is highly likely to be a split fiber. Fibers composed of a single component such as cellulose fiber, wholly aromatic polyamide fiber, wholly aromatic polyester fiber, polyimide fiber, and polybenzoxazole fiber obtained by the solvent spinning method are also fibrillable separable fibers. . That is, when the gas is actually ejected from the nozzle into the gas by the action of the compressed gas, the fiber that is incompletely divided and fibrillated as if it were a pulp-like material is a separable fiber.
[0041]
Such an assembly of the split fibers is a collection of the split fibers as described above, and the number thereof is not particularly limited. Further, the aggregation state is not particularly limited, and examples thereof include a regularly oriented state and a randomly oriented agglomerated state.
[0042]
You may use combining the aggregate of a different kind of splitting fiber as this splitting fiber assembly.
[0043]
The aggregate of the split fibers according to the present invention can be obtained, for example, by converging after spinning by a conventional spinning method.
[0044]
In the method for producing an electrode material of the present invention, as described above, an assembly of ultrafine fibers (A), an assembly of splittable fibers that can be divided into ultrafine fibers (B), and an aggregate of pulp-like materials (C) At least one aggregate selected from the aggregate (D) of separable fibers that can be fibrillated is used. There are 15 combinations of these (A) to (D), but among these, the combination of the assembly of ultrafine fibers (A) and the assembly of pulp-like materials (C) improves the uniformity of the electrode material. This is a particularly preferred combination because the pulp-like material is fibrillated and easily entangled, the strength of the electrode material can be increased, and the retention of activated carbon and acetylene black is also high. In the case of this combination, the blending ratio is such that the strength of the electrode material is improved by pulp-like fibrils, the retention of activated carbon and acetylene black is excellent, and the uniform dispersibility is not impaired. ) = 30-90: 70-10, and (A) :( C) = 40-90: 60-10 is more preferable.
[0045]
Further, the content of activated carbon in the electrode material is preferably 60% or more of the total mass of the electrode material and more preferably 70% or more so that the energy density can be increased. In addition, it is preferable to mix | blend so that it may become 80% or less from the relationship with acetylene black and an aggregate. Further, the content of acetylene black in the electrode material is preferably 10% or more of the total mass of the electrode material so that the electrical conductivity can be increased. In order to increase the energy density, the content of acetylene black is 20%. % Or less is preferable. On the other hand, the aggregate is preferably 10% or more of the total mass of the electrode material so that dimensional stability can be imparted to the electrode material. If the aggregate exceeds 20% of the total mass of the electrode material, the insulating portion increases and the electrical When the conductivity is low, the energy density is low. Therefore, it is preferable to blend so that 20% or less of the total mass of the electrode material becomes the aggregate. That is, it is preferable to mix so that the mass ratio of (activated carbon) to (acetylene black) to (aggregate) is 6 to 8: 2 to 1: 2 to 1.
[0046]
Next, the activated carbon and acetylene black as described above and at least one aggregate are supplied to the nozzle, and the activated carbon and acetylene black are dispersed by being ejected from the nozzle into the gas by the action of the compressed gas. Ultrafine fibers and / or pulp-like materials are generated from the aggregate and dispersed.
[0047]
The nozzle may have a constant cross-sectional area from the supply side of activated carbon, acetylene black and aggregate to the ejection side, or the cross-sectional area may be reduced continuously or discontinuously. The cross-sectional area may be increased continuously or discontinuously, or may be decreased continuously or discontinuously after the cross-sectional area is increased. Alternatively, it may increase continuously after the cross-sectional area decreases continuously or discontinuously.
[0048]
In addition, if the flow of the compressed gas supplied to the nozzle is spiral, the aggregates are entangled with each other, and it tends to be difficult to generate ultrafine fibers and / or pulp-like materials or to uniformly disperse them. It is preferred that the flow of compressed gas supplied to the nozzle is substantially laminar. As a nozzle capable of supplying a substantially laminar compressed gas in this way, for example, a Venturi tube can be mentioned.
[0049]
Also, activated carbon, acetylene black, ultrafine fibers and / or pulp-like materials collide with activated carbon, acetylene black and aggregates, or ultrafine fibers and / or pulp-like materials generated from aggregates in the vicinity of the nozzle ejection part. In order to disperse or promote the generation of ultrafine fibers and / or pulp-like materials from the aggregate, it is preferable to provide a collision member. The distance between the collision member (flat portion) and the nozzle ejection portion is preferably 1 to 100 mm, more preferably 5 to 40 mm, still more preferably 5 to 30 mm, and more preferably 10 to 30 mm. Is more preferable, and it is most preferable that it is 10-20 mm.
[0050]
Any gas may be used as the compressed gas, but air is suitable for manufacturing. In addition, the compressed gas disperses activated carbon and acetylene black, and generates a fine fiber and / or pulp-like material from the aggregate so that the gas passing speed at the nozzle outlet is 100 m / sec. The above is preferable. This “gas passage speed” is the flow rate of the gas ejected from the nozzle at 1 atm (m ³ / Sec) is the cross-sectional area (m ² The value divided by). The pressure of the compressed gas is 2 kg / cm so that activated carbon and acetylene black can be dispersed, and fine fibers and / or pulp-like materials can be generated and dispersed from the aggregate. ² The above is preferable.
[0051]
Further, the gas as a dispersion medium for dispersing the activated carbon, acetylene black, ultrafine fibers and / or pulp-like material ejected from the nozzle is not particularly limited, but air is suitable for production. .
[0052]
In addition, if the adhesion rate of the deposits such as the surfactant and the paste is low, static electricity is likely to be generated due to friction with the activated carbon, acetylene black, and / or the aggregate, and the activated carbon, acetylene black, ultrafine fibers and Since pulp-like materials are also easily charged with static electricity, they repel each other and are easily dispersed uniformly. Therefore, it is preferable to perform a process of removing the deposits before supplying the aggregate to the nozzle. For example, the aggregate is preferably washed with a solvent such as acetone to reduce the amount of deposits, and the activated carbon and acetylene black are preferably dried to remove moisture. In addition, in the case of the ultrafine fiber aggregate formed by extracting the sea component of the sea-island type fiber, it is a suitable ultrafine fiber aggregate because it has a small amount of deposits. Even if the ultrafine fiber aggregate is formed by extracting the sea components of the sea-island fiber, it is preferable to wash it with a solvent such as acetone to further reduce the amount of deposits.
[0053]
Subsequently, the dispersed activated carbon, acetylene black, ultrafine fibers and / or pulp-like materials are accumulated to form an activated carbon-containing aggregate. Accumulation of the activated carbon, acetylene black, ultrafine fibers and / or pulp-like material can be carried out using a support such as a porous roll or net. In addition, activated carbon, acetylene black, ultrafine fibers, and / or pulp-like materials may be naturally dropped and accumulated, or gas may be sucked and accumulated from below the support. When the gas is sucked and accumulated, the activated carbon-containing aggregate in a state where the activated carbon, acetylene black, ultrafine fibers and / or pulp-like materials are in close contact can be obtained by increasing the suction force.
[0054]
Next, the activated carbon and acetylene black can be fixed with the ultrafine fibers and / or pulp-like material of the activated carbon-containing assembly to produce an electrode material. Although this fixing method is not particularly limited, for example, a method of fixing by fusion or pressure bonding of ultrafine fibers and / or pulp-like material, fibrillation of the pulp-like material is promoted by applying pressure, and this fibril And the like, and a method of confining activated carbon and acetylene black by promoting entanglement between pulp-like materials and / or pulp-like materials and ultrafine fibers. Among these, it is preferable to fix by fusion or pressure bonding of ultrafine fibers and / or pulp-like materials, and more preferably to fix by fusion of ultrafine fibers. As described above, when the electrode material form is maintained by fusion or pressure bonding (particularly, fusion of ultrafine fibers) of ultrafine fibers and / or pulp-like materials, the electrode material form is excellent in mechanical strength and can be maintained. In addition, the activated carbon and acetylene black can be eliminated, which is preferable.
[0055]
According to the method for producing an electrode material of the present invention as described above, activated carbon and acetylene black are the surfaces of ultrafine fibers and / or pulp-like materials, between ultrafine fibers, between pulp-like materials, or between ultrafine fibers and pulp-like materials. Since the gap formed by the ultrafine fibers and / or the pulp-like material can be filled in close proximity, an electrode material having a high electric conductivity and a sufficient amount of electric double layer capacity can be manufactured. Since this manufacturing method is a method of manufacturing by dispersing and accumulating in a gas, it is not necessary to knead, and an electrode material with high uniformity is manufactured with good workability and continuously with stable quality. be able to. The thickness can be adjusted by the fixing step after the activated carbon-containing assembly is formed, and the thickness can be easily reduced. Further, since the basis weight can be easily adjusted by adjusting the amount of the raw material to be supplied (activated carbon, acetylene black, aggregate), an intended electrode material having a high energy density can be produced. Furthermore, even if it is an aggregate of pulp-like materials that have conventionally been difficult to open, it can be efficiently and uniformly opened into pulp-like materials, and the pulp-like materials are excellent in retention of activated carbon and acetylene black. There is also an effect.
[0056]
Next, the manufacturing method of the electrode material of the present invention will be described based on FIG. 1 which is a schematic cross-sectional view of a manufacturing apparatus capable of manufacturing the electrode material of the present invention.
[0057]
First, the activated carbon, acetylene black, and aggregate (that is, at least one selected from an ultrafine fiber aggregate, an aggregate of split fibers, a pulp aggregate, and a split fiber aggregate) are mixed in the mixing device 10. Mixed by.
[0058]
Next, the mixed activated carbon, acetylene black and aggregate are supplied to the nozzle 30. Before the activated carbon, acetylene black and aggregate reach the nozzle 30, activated carbon, acetylene black and aggregate are vigorously moved from the nozzle 30 into the gas 40 by the action of the compressed gas introduced from the compressed gas introduction port 20. Is ejected. When the gas is ejected to the gas 40, the pressure difference between the inside of the nozzle 30 and the gas 40, the turbulent flow formed between the ejected compressed gas and the gas 40, or the nozzle 30 is provided near the ejection port. The activated carbon and acetylene black are dispersed by the interaction such as collision with the colliding member, and ultrafine fibers and / or pulp-like materials are generated and dispersed from the aggregate.
[0059]
The activated carbon, acetylene black and ultrafine fibers and / or pulp-like material 70 dispersed in the gas 40 are accumulated on a support 50 made of a net to form an activated carbon-containing assembly 80. In this manufacturing apparatus, since the gas can be sucked by the gas suction device 60 positioned below the support 50, a relatively dense activated carbon-containing assembly 80 can be formed.
[0060]
The activated carbon-containing assembly 80 formed in this way is supplied again to the nozzles 31 and 32 in order to further improve the dispersibility of the activated carbon, acetylene black, ultrafine fibers and / or pulp. In this manufacturing apparatus, two nozzles are supplied again, but one nozzle may be supplied again, three or more nozzles may be supplied again, and the activated carbon-containing assembly 80 may be used as it is. You may supply to the heat sealing | fusion apparatus 90 as mentioned later.
[0061]
Similarly, when the gas is again supplied to the nozzles 31 and 32, activated carbon, acetylene black, ultrafine fiber, and the like by the action of the compressed gas introduced from the compressed gas introduction ports 21 and 22 just before reaching the nozzles 31 and 32. The pulp-like material is vigorously ejected from the nozzles 31 and 32 into the gases 41 and 42, respectively. At this time, similarly, the activated carbon, acetylene black, ultrafine short fibers and / or pulp-like materials are uniformly dispersed.
[0062]
The activated carbon, acetylene black, ultrafine fibers, and / or pulp-like materials 71 and 72 dispersed in the gases 41 and 42 are respectively accumulated on the support 51 made of a net to form an activated carbon-containing aggregate again. In this manufacturing apparatus, first, activated carbon, acetylene black, ultrafine fibers, and / or pulp-like material 71 ejected from the nozzle 31 are accumulated on the support 51 to form a single-layer activated carbon-containing assembly 81, On this single-layer activated carbon-containing assembly 81, activated carbon, acetylene black, ultrafine fibers and / or pulp-like material 72 ejected from the nozzle 32 are accumulated to form a stacked activated carbon-containing assembly 82. Note that even though the activated carbon-containing aggregates are laminated, since the activated carbon, acetylene black, ultrafine fibers and / or pulp-like materials that originally constitute the single-layer activated carbon-containing aggregate 80 are dispersed again, a clear layer is formed. It is not formed.
[0063]
Further, when the activated carbon, acetylene black, ultrafine fibers and / or pulp-like materials 71 and 72 are accumulated, the gas is sucked by the gas suction device 61 located below the support 51, so that it is relatively dense. A laminated activated carbon-containing assembly 82 can be formed. In this manufacturing apparatus, both the gas 41 and the gas 42 are sucked by one gas suction device 61, but a gas suction device may be provided for each gas.
[0064]
Next, the laminated activated carbon-containing assembly 82 is supplied to the heat fusion apparatus 90, and the fine fibers and / or pulp-like materials are fused by the action of heat of the heat fusion apparatus 90 to obtain activated carbon and acetylene black. Can be fixed to produce an electrode material. Then, the electrode material is wound up by the winding device 100.
[0065]
Examples of the present invention will be described below, but the present invention is not limited to these examples.
[0066]
【Example】
(Example)
Made of low-density polyethylene and polypropylene, and fusion-bondable ultrafine fibers in which at least a part of the fiber surface is occupied by low-density polyethylene (cross-sectional shape: sea-island type, fineness = 0.03 dtex, fiber diameter = 2 μm, cut fiber length = 2 mm , An aggregate of substantially the same diameter in the fiber axis direction (a state of being gathered by water in parallel bundles), 8 mass%, an aggregate of para-type wholly aromatic polyamide pulp (fiber length = 0.38 mm) 2% by mass, acetylene black powder (manufactured by Denki Kagaku Kogyo Co., Ltd., Denka Black, average particle size = 0.1 μm), 10% by mass, activated carbon powder (manufactured by Kuraray Chemical Co., Ltd., YP-17, petroleum pitch type Kuraray coal activated carbon, surface area: 2000m ² / G, average particle size = 5 μm) was fed to the mixer at a mass ratio of 80 mass%, and these were dissolved and mixed. The fusible ultrafine fibers were washed with acetone and dried at a temperature of 70 ° C., and para-type wholly aromatic polyamide pulp, activated carbon powder and acetylene black powder were dried at a temperature of 120 ° C.
[0067]
Next, these mixtures are supplied to a venturi tube having a circular cross section at the jet outlet (diameter: 8.5 mm) (a cross sectional shape on the supply side of the venturi tube is circular (diameter: 3 mm)), and before the venturi tube. Compressed air (pressure: 6 kg / cm ² A substantially laminar flow), and the mixture is ejected from the venturi tube into the air (the gas passage speed at the venturi tube outlet: 118 m / s), and the collision is provided in front of the venturi tube outlet. Collide with a member (distance between venturi tube outlet and flat part of impact member: 15 mm) to disperse activated carbon powder, acetylene black powder, fusible ultrafine fibers, and para-type wholly aromatic polyamide pulp It was.
[0068]
Next, this dispersed activated carbon powder, acetylene black powder, fusible ultrafine fiber, and para-type wholly aromatic polyamide pulp were placed on a support made of a net (non-woven fabric substrate (weight per unit) 30 g / m ² To form an activated carbon-containing aggregate. When accumulating, air is sucked in by a suction box installed under the support (2 m ³ / Min).
[0069]
Next, the activated carbon-containing assembly-nonwoven fabric base material laminate is supplied to an oven set at a temperature of 130 ° C., subjected to heat treatment for 3 minutes, and only the low-density polyethylene of the meltable ultrafine fibers is fused, 350 g / m ² An activated carbon-containing assembly-nonwoven fabric base material composite having a thickness of 850 μm was produced.
[0070]
Next, the nonwoven fabric base material is peeled from the activated carbon-containing assembly-nonwoven fabric base material composite, and only the activated carbon-containing assembly is subjected to thermal calendering (pressure: 500 N / cm, temperature: 140 ° C.), and the basis weight is 320 g / m. ² In addition, an electrode material having a thickness of 500 μm (containable ultrafine fiber: 8 mass%, para-type wholly aromatic polyamide pulp: 2 mass%, acetylene black powder: 10 mass%, activated carbon powder: 80 mass%) continuously Manufactured. In this electrode material, each constituent material was uniformly dispersed. Further, in this electrode material, the activated carbon and acetylene black are closely packed in a three-dimensional fiber structure formed of fusible ultrafine fibers and para-type wholly aromatic polyamide pulp, and 256 g / m ² It was easy to predict that the energy density was high. Further, activated carbon and acetylene black were fused, adhered, or pressure-bonded on the surfaces of the fusible ultrafine fibers and the para-type wholly aromatic polyamide pulp. Note that the fusible ultrafine fibers and the para-type wholly aromatic polyamide pulp were also oriented in the thickness direction of the electrode material.
[0071]
【The invention's effect】
The method for producing an electrode material for an electric double layer capacitor of the present invention can produce an electrode material having a high energy density, a thin and uniform thickness, and having a stable quality with good reproducibility.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a production apparatus that can be used for producing an electrode material for an electric double layer capacitor of the present invention.
[Explanation of symbols]
10 Mixing device
20, 21, 22 Compressed gas inlet
30, 31, 32 nozzles
40, 41, 42 Gas
50, 51 Support
60, 61 Gas suction device
70, 71, 72 Activated carbon, acetylene black, ultrafine fiber and / or pulp
80 Aggregates containing activated carbon
81 Single-layer activated carbon-containing assembly
82 Stacked activated carbon-containing assembly
90 heat fusion equipment
100 Winding device

Claims (4)

Aggregates of activated carbon, acetylene black, and ultrafine fibers having a fiber diameter of 5 μm or less, aggregates of split fibers that can be divided into ultrafine fibers having a fiber diameter of 5 μm or less by the action of compressed gas, aggregates of pulp-like materials, compression The activated carbon and the acetylene black are produced by jetting at least one aggregate selected from an aggregate of separable fibers that can be fibrillated into a pulp form by the action of gas into the gas from the nozzle by the action of compressed gas. with dispersing, the aggregate step of dispersing the ultrafine fibers and / or pulp-like material, dispersed active carbon, acetylene black, and integrating the ultrafine fibers and / or pulp-like material, to form an activated carbon-containing aggregate Electric double layer capacitor by fixing activated carbon and acetylene black with process, activated carbon containing aggregate ultrafine fiber and / or pulp A method for producing an electrode material for an electric double layer capacitor, comprising: a step of forming an electrode material for a battery.   The method for producing an electrode material for an electric double layer capacitor according to claim 1, wherein the activated carbon and acetylene black are fixed by fusion of ultrafine fibers.   3. The electrode material for an electric double layer capacitor according to claim 1, wherein the pulp is made of a resin selected from wholly aromatic polyamide resin, polyimide resin, and polybenzimidazole resin. Method.   It mix | blends so that the mass ratio of (activated carbon) vs. (acetylene black) vs. (aggregate) may be set to 6-8: 2 to 1: 2-1. Manufacturing method of electrode material for electric double layer capacitor.

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