JP2000331882A - Electric double-layer capacitor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-reliability electric double-layer capacitor which is widely used for various kinds of electric devices, for regenerative power of electric vehicles and for storage of power. SOLUTION: By impregnating a collector 3 constituting the electric double- layer capacitor with water, winding it into a specified shape in a softened state, and drying the collector 3 after winding, defects such as cracks or peeling off at the time of winding can be prevented even if the thickness of the collector 3 is increased and its cost of manufacture can also be reduced. Also, by using a waterproof separator 16 at that time, the yield of products is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric double layer capacitor used for regenerating driving motors such as various electric devices and electric vehicles and for storing electric power, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as an electric double layer capacitor,
One described in Japanese Patent Application Laid-Open No. 3-280518 is known. In such an electric double layer capacitor, a current collector is wound around a separator and sealed in a case together with a non-aqueous electrode solution.

[0003] Electric double layer capacitors are required to have large capacity, low cost, and improved reliability. FIG.
FIG. 1 shows a structure diagram of a wound electric double layer capacitor for 10 F (farad) to several thousand F high power. In FIG. 8, reference numeral 1 denotes a case, 2 denotes a conductive foil, and a current collector 3 is formed on one or both surfaces of the conductive foil 2.
Reference numeral 5 denotes a wound body, and a plurality of current collectors 3 have a separator 4 therebetween.
It is wound around. Reference numeral 6a denotes an extraction electrode, which is connected to the plurality of conductive foils 2 mutually. Reference numeral 7 denotes a sealing material, and reference numeral 8 denotes a terminal provided on the sealing body 7.

[0004] In the electric double layer capacitor proposed so far, it has been proposed to use a resin containing fluorine as a binder (binder or adhesive, often a resin). Was an issue.
Thus, for example, a method using a polysaccharide such as carboxymethylcellulose or carboxymethylstarch as a binder proposed in Japanese Patent Publication No. 59-44448 is disclosed in JP-A-4-88619. Agents using water-soluble polysaccharides such as carboxymethylcellulose and water-soluble chicken and derivatives thereof, and JP-A-63-181307 discloses sodium alginate having a carboxyl group or an alkali metal salt thereof as an electrode binder. Those using polysaccharides have been proposed.

Activated carbon is adhered to such a material as a binder, and is used as a current collector (which is a constituent part of an electric double layer and refers to an activated carbon coating film formed on a base metal foil). However, since the raw material of such materials is pulp (cellulose), all of these cellulose derivatives are cellulose at the center of the molecular chain (having a long-chain structure in which a glucopyranose molecule has a β-glucoside bond at the 1,4 position). However, the cellulose molecule has a micellar structure and is easily crystallized, and is therefore hard and brittle because it corresponds to the bone of a plant.

[0006] In order to increase the coating density of an electrode coating using such a resin material, even if a press proposed in Japanese Patent Application Laid-Open No. 57-60828 or the like is performed, there is no flexibility. If it is not a press, the coating density will not increase. In the case of a high-pressure press, there was a problem in cracking or peeling of the electrode coating film or elongation or deformation of the aluminum foil itself. Pressing pressure can be reduced somewhat by reducing the amount of resin, but the binding power of the current collector is insufficient. Specifically, the adhesive strength between the metal foil and the activated carbon coating film is insufficient, and cohesive failure of the activated carbon coating film itself occurs, so that the electrode coating film is easily cracked or peeled at the time of winding. For this reason, in the case of such a binder, it is necessary to perform the pressing while keeping the moisture remaining in the current collector and the moisture tends to remain in the current collector.

In particular, in the case of an electric double layer capacitor using a non-aqueous electrolyte, if water enters the inside, a cause of deterioration of withstand voltage,
The decomposition voltage of an organic solvent system is 3 V, whereas the decomposition voltage of an aqueous system tends to be as low as about 1 V. In the case of such a conventional binder, the binder itself is water-soluble, and therefore has a high water absorption property, and it is difficult to remove the residual water. Such a phenomenon is disclosed in
Alginic acid polysaccharides proposed in, for example, JP-A-3-181307 also occur similarly.

On the other hand, in Japanese Patent Application Laid-Open Nos. 62-179711 and 62-16506, activated carbon is dispersed in artificial latex to prepare a mixed solution, and agglomerates obtained by dehydration treatment are dried. Then, it is proposed to pulverize the agglomerate, further granulate this, pressurize this granulated powder, and mold it. Therefore, it cannot be applied to the production of large-capacity, for example, wound or laminated electric double-layer capacitors of 4,000 F or more, which are required for industrial and electric vehicles. .

Japanese Patent Application Laid-Open No. 6-316784 discloses the use of an ultrasonic homogenizer as a method for producing a uniform mixed powder of carbon black and PTFE.
JP-A-3849 and JP-A-8-203536 propose the use of an ultrasonic homogenizer as a method for dispersing a catalyst and nickel together with carbon black in a fuel electrode of a fuel cell, a method for producing the catalyst and a method for operating the battery. However, high dispersion was limited.

Japanese Patent Application Laid-Open No. 63-104316 proposes to use a polarizable electrode made of an elastomer having a glass transition temperature of -10 ° C. or less for Ketjen Black. Here, copolymers and various rubber materials have been proposed as elastomers. However, these materials dissolve the binder in the organic solvent, mix Ketjen Black with this, disperse both, evaporate the solvent,
Further, they are blended by a roll and are to be molded. However, such a method has been created by a method of manufacturing rubber kneaded materials such as tires for a long time, and it is difficult to create a high capacity battery such as a lithium secondary battery or a lead secondary battery. Such a case is disclosed in Japanese Patent Laid-Open No. 7-3312.
No. 01 also proposes kneading a rubber material as a binder for expanded graphite. In this case, the rubber material is dissolved in a solvent such as toluene, added with carbon powder, kneaded, and then heat-treated.

In Japanese Patent Application Laid-Open No. 8-250380, a powder obtained by dissolving a powder such as acrylonitrile butadiene rubber in a solvent such as xylene is mixed with activated carbon powder or acetylene black, and finally the solvent is evaporated. Of the mixture obtained by using a pressure molding method or an extrusion molding die to a thickness of 50 to 50 μm.
A method of molding to 500 μm has been proposed. In such a conventional dissolution method, the rubber material is completely dissolved (in other words, dissolved or dispersed to a molecular state of several angstroms), thereby closing the fine pores of several angstroms on the surface of the activated carbon and lowering the capacity value of the product. Was a problem. In order to solve these problems, kneading with rubber and a method of molding have been devised, but there was a limit.

In recent years, as a more environmentally friendly product, when an activated carbon or a conductivity-imparting agent is applied as a current collector together with a resin on a conductive foil, a solvent mainly composed of water instead of an organic solvent is used. It is considered to use. However, when water is mainly used, drying energy of the current collector is required more than when a low-boiling organic solvent is used. Alternatively, the current collector itself (and the resin itself) easily absorbs moisture,
The remaining moisture remaining inside the current collector, and the absorption and absorption of moisture by the in-process product become problems. It has been experimentally confirmed that as a general electric double layer capacitor, long-term reliability may be adversely affected unless the residual moisture in the product is reduced to 200 ppm or less. The reason for this is that when a voltage is applied, a voltage is also applied to the residual moisture,
For this reason, it is considered that the residual water is electrolyzed at a lower voltage than the non-aqueous electrolyte.

[0013] In order to increase the capacity of the electric double layer capacitor, a high thickness of the current collector is desired. However, when the current collector is thick, there is a problem that cracks and cracks occur in the current collector during winding. FIGS. 9A to 9C show an example of a method for evaluating the winding property. In FIG. 9, 9
Is a round bar, and by winding an aluminum foil 2 having a current collector 3 bound on at least one surface cut into a product width around the round bar 9, the winding property of the current collector 3 is improved. To evaluate. FIG. 9A shows a state in which the current collector 3 has been peeled off from the aluminum foil 2 and the current collector 3 itself has formed a fractured surface 10, and it is impossible to evaluate this state.
FIG. 9B shows a state in which the current collector 3 is not peeled off from the aluminum foil 2 and fine cracks 11 are formed on the surface of the current collector 3, and evaluation of this state is poor in winding property. FIG.
(C) is a state in which the aluminum foil 2 is not peeled off from the current collector 3 and no damage such as cracks or cracks has occurred on the surface of the current collector 3, and the normal surface 12 is the same surface state as before the winding. The evaluation of this state shows that the winding property is good.

Incidentally, such evaluation is based on aluminum foil 2
It is preferable that the current collectors 3 are formed on both sides of the substrate, and the operations are alternately performed 10 to 100 times on both sides. For example, even if a current collector is manufactured using the same electrode solution, cracks and cracks are more likely to occur when the rollability is evaluated as the thickness increases. For example, an electrode solution having a certain composition is prepared, and a current collector having a thickness of 30 μm is formed on an aluminum foil using the electrode solution. Even if the winding property is good, a current collector having a thickness of 100 μm is formed. When the reversibility is evaluated, cracks, cracks or peeling may occur, and the thickness is further 1000 μm.
When the current collector is prepared, cracks, cracks or peeling often occur.

As described above, poor winding is likely to occur at a thickness of 100 μm or more.
In some cases, winding failure may occur at μm, and in some cases, it may be OK. For this reason, conventionally, to solve such problems,
It is necessary to change the composition and composition of the electrode solution according to the hardness and flexibility of the current collector coating, for example, according to the thickness of the current collector, which increases the cost of the product.

Conventionally, since the current-collector coating film in a dried state has been wound a predetermined number of times through a separator, ordinary paper is used for the separator itself.

[0017]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and obtains long-term reliability by minimizing water contained in a current collector portion while increasing the capacity. It is an object of the present invention to provide a low-cost electric double layer capacitor.

[0018]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention relates to a method in which a current collector is coated on a current-collecting film which is liable to crack, crack, peel off, etc. in the winding step. To increase the flexibility and prevent the occurrence of fine cracks, cracks and peeling by winding, and by drying the current collector itself after winding, it can be applied to thicker current collectors. It is intended to minimize cracking and chipping of the film, and by using a water-resistant separator, even if the current collector and the separator are hydrated, they do not short-circuit with each other, and they are wound in a hydrated state. It is hard to generate stress in the current collector because it is turned, and by drying, curing or polymerizing in the wound state, the residual stress in the wound state can be reduced as much as possible, and the product itself is stable. You can enhance the nature.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention relates to a method for forming a plurality of conductive foils, each of which is coated with activated carbon and a conductivity-imparting agent on one side or both sides as a current collector with a thickness of 100 μm or more. An electric double-layer capacitor that is wound through one or more water-resistant separators, taken out in a predetermined non-aqueous electrode solution and sealed together with electrodes, and the winding process is performed by using a water-resistant separator. In this case, even when wound using a current collector containing water, defects such as short-circuiting hardly occur.

According to a second aspect of the present invention, a plurality of conductive foils in which activated carbon and a conductivity-imparting agent are applied as a current collector to one or both surfaces with a thickness of 100 μm or more on a resin are interposed via a separator. In an electric double-layer capacitor which is wound and sealed together with an extraction electrode in a non-aqueous electrode solution, the current collector is impregnated with water and dried while being wound, and then encapsulated together with the extraction electrode in a predetermined non-aqueous electrode solution. This is a method for manufacturing a double-layer capacitor, in which the current collector is wound into a predetermined shape in a state of containing water containing a large amount of a solvent component, and the contained solvent component acts as a kind of plasticizer,
Even a thick current collector coating film can be wound into a predetermined shape without generating cracks and peeling, and after being wound into a predetermined shape, the current collector is dried and contained in the current collector. Water is not a problem.

According to a third aspect of the present invention, a plurality of conductive foils, each of which is coated with activated carbon and a conductivity-imparting agent as a current collector on one or both sides with a thickness of 100 μm or more on a resin, via a separator, are provided. Wound, in an electric double layer capacitor sealed with a take-out electrode in a non-aqueous electrode solution, the current collector is wound in a state of being hydrated, and then heat is applied by applying a current to the conductive foil or current collector. A method for manufacturing an electric double layer capacitor in which the current collector is dried and then taken out into a predetermined non-aqueous electrode solution and sealed together with an electrode, wherein the current collector is wound into a predetermined shape while being hydrated. The contained water acts as a kind of plasticizer and can be rolled into a predetermined shape even with a thick current collector coating without causing cracks or peeling, and a conductive foil after being wound into a predetermined shape Alternatively, charge the current collector To generate Joule heat by applying a possible heating the current collector from the inside, can be short to ensure removal of water contained in the interior of the current collector is enhanced product reliability.

According to a fourth aspect of the present invention, the activated carbon and the conductivity-imparting agent are combined with a resin on one side or as a current collector.
In the electric double layer capacitor in which a plurality of conductive foils applied with a thickness of 00 μm or more are wound through a separator and taken out in a non-aqueous electrode solution and sealed together with electrodes, the current collector is hydrated and wound. A method for manufacturing an electric double layer capacitor in which an external electromagnetic field is applied so as to generate an eddy current and the current collector is dried and then taken out in a predetermined non-aqueous electrode solution and sealed together with an electrode. Will be wound into a predetermined shape in a state of containing water, and the contained water acts as a kind of plasticizer, and even a thick current collector coating without a crack or peeling is wound into a predetermined shape. Also, after being wound into a predetermined shape, the current collector can be heated from the inside by generating an eddy current in the conductive foil or the current collector, and water contained in the current collector can be removed in a short time. Reliable removal, product reliability It is enhanced.

According to a fifth aspect of the present invention, a plurality of conductive foils in which activated carbon and a conductivity-imparting agent are applied as a current collector to one or both surfaces with a thickness of 100 μm or more on a resin are interposed via a separator. In an electric double-layer capacitor which is wound and enclosed together with an extraction electrode in a non-aqueous electrode solution, the current collector is impregnated with water and wound with a gap formed between the current collectors, and then heated and dried in this state. After that, it is a method of manufacturing an electric double layer capacitor in which a predetermined non-aqueous electrode solution is taken out and sealed together with an electrode, and the current collector is wound into a predetermined shape while being hydrated, and the contained water is removed. Acts as a kind of plasticizer, it can be wound into a predetermined shape even with a thick current collector coating without generating cracks or peeling, and it can be wound so that gaps are formed in the wet state , The collection Body can be in contact over a wide area outside air or hot air, a vacuum, etc., can be short to ensure removal of water contained in the interior of the current collector is enhanced product reliability.

According to a sixth aspect of the present invention, a plurality of conductive foils having activated carbon and a conductivity-imparting agent applied to a resin and having a thickness of 100 μm or more on one or both sides as a current collector are formed through a separator. In an electric double layer capacitor which is wound up and sealed together with an extraction electrode in a non-aqueous electrode solution, the current collector is wound in a water-containing state, dried in vacuum, and then removed in a predetermined non-aqueous electrode solution. This is a method of manufacturing an electric double layer capacitor that is enclosed together with the current collector, and the current collector is wound into a predetermined shape while containing water, the water contained acts as a kind of plasticizer, causing cracking and peeling Even a thick current collector coating can be wound into a predetermined shape without causing the water to evaporate in a vacuum after being wound into a predetermined shape, so that water contained inside the current collector can be removed for a short time. Products can be reliably removed It is enhanced reliability.

According to a seventh aspect of the present invention, a plurality of conductive foils having activated carbon and a conductivity-imparting agent applied as a current collector to one or both surfaces with a thickness of 100 μm or more on a resin are interposed via a separator. In an electric double-layer capacitor wound and wound together with an extraction electrode in a non-aqueous electrode solution, the current collector is wound in a state of being hydrated, then the current collector is dried, and a central portion of the current collector is dried. A method for manufacturing an electric double-layer capacitor in which a jig is inserted into a current collector, and the current collector is wound up to a predetermined size, and then taken out into a predetermined non-aqueous electrode solution and sealed together with an electrode. Even if a gap is formed between the current collector and the adjacent separator after the formation, the coil can be wound into a smaller diameter by winding it up, and the capacity density per unit volume of the electric double layer capacitor can be increased.

The invention according to claim 8 of the present invention is characterized in that a plurality of conductive foils having activated carbon and a conductivity-imparting agent applied as a current collector to one or both surfaces with a thickness of 100 μm or more on a resin are interposed via a separator. In an electric double layer capacitor wound and sealed together with an extraction electrode in a non-aqueous electrode solution, the current collector is wound together with a water-containing separator, and after the separator and the current collector are dried, a predetermined non-aqueous electrode This is a method of manufacturing an electric double layer capacitor that is taken out in a liquid and sealed together with an electrode.The current collector is wound at the same time as a water-containing separator, so that the water contained acts as a kind of plasticizer, causing cracks and peeling. Thick current collector coatings can be wound into a given shape without causing any problems, and water is evaporated from the current collector and separator after being wound into a given shape. The enhanced.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

(Embodiment 1) FIG. 1 shows a structure of an electric double layer capacitor according to the present invention and a part of steps of a manufacturing method. In FIG. 1A, reference numeral 13 denotes a raw material, and the conductive foil 2
The current collector 3 is wound by a predetermined length (the conductive foil 2 and the current collector 3 are omitted in FIG. 1A). Reference numeral 14 denotes a spray, which sprays a predetermined amount of water 15 on the surface of the current collector 3. Generally, the raw material 13 has a diameter of 100 to 200 mm in order to improve workability.
Are continuously wound up. Reference numeral 16 denotes a water-resistant separator. The plurality of conductive foils 2 and the current collectors 3 are wound into a product shape via the water-resistant separator 16 to form a wound body 5. Since the dimensions of the wound body 5 are the product dimensions, the wound body 5
The diameter of the central part of the raw material 13 is about 0.5 mm to 3 mm.
It will be wound much smaller than. That is,
In the material 13, since the current collector 3 is wound around the thick core, no winding failure occurs, but the center of the wound body 5 is 0.5 mm.
It will be extremely tightly wound up to about 3 mmφ.

FIG. 1B shows a state in which the current collector is hydrated, and corresponds to an enlarged view near the spray 14 in FIG. 1A. In FIG. 1B, the conductive foil 2 has a current collector 3 on its surface.
Is sent in the direction of the arrow while forming. On the way, the current collector 17 is hydrated by the water 15 spouted from the spray 14. Note that, depending on the type of the current collector and the water content, the thickness of the current collector 17 containing water may be larger than the thickness of the current collector 3 as shown in FIG. Here, by using the water-resistant separator 16, short-circuiting between the hydrated current collectors is prevented.

This will be described in more detail. First, the curvature of the central portion of the web 13 was set to 100 mm from the viewpoint of workability. On the other hand, the curvature of the central portion of the current collector in the product of the electric double layer capacitor was 1 mm. Further, current collectors 3 having different thicknesses were formed on the conductive foil 2 using the same electrode solution. Synthetic paper was used as the water-resistant separator 16. For comparison with a conventional example, an electric double layer capacitor was similarly formed using current collectors having different thicknesses. First, the current collector thickness is 50 μm
As shown in FIG. 9 (C), even when wound with a curvature of 1 mm, the winding property was good. However, the current collector thickness is 100μ
At the time of m, there was a part corresponding to poor winding property as shown in FIG. 9B. The current collector thickness is 150 μm
In this case, the winding property was poor as shown in FIG. 9B (the winding was partially impossible as shown in FIG. 9A).

Therefore, as shown in FIGS. 1A and 1B, an experiment was carried out in which the current collector 3 was moistened with a fine mist of water 15 jetted from a spray 14 at a predetermined ratio. In the case of the current collector 17 containing water, the thickness of the current collector 50 μm, 100 μm, 1
In any of the cases of 50 μm, 200 μm, and 300 μm, by adjusting the water content, poor winding property as shown in FIG. 9B did not occur.

Further, it can be predicted that this phenomenon is due to the fact that the water permeated into the current collector acts as a kind of plasticizer and relaxes the stress in the coating film generated at the time of winding. Further, in the present embodiment, since the current collector may be wetted with water immediately before winding,
It is not affected by the amount of moisture contained in the raw fabric itself.
That is, a sufficiently dried raw material can be used. Although it is possible to increase the amount of residual moisture in the raw material itself by relaxing the drying conditions of the electrode solution, it is difficult to adjust the amount of water remaining in the raw material in this case. In addition, the raw fabric itself becomes heavy because it contains water, and the workability is poor. In addition, when the residual moisture in the raw material is large, the conductive foil in the current collector, particularly, the aluminum foil may be corroded. This can occur rarely if the chemicals used to activate the activated carbon remain in the activated carbon as ions, and perhaps this phenomenon
It is considered that the residual ions cause the aluminum foil to be corroded and oxidized by a kind of battery effect. In order to prevent such a phenomenon, the amount of water in the raw material is desirably equal to or less than a certain amount, but is not limited thereto.

FIG. 2 shows how water is removed from a wound body 5 composed of a plurality of water-containing current collectors and separators. In FIG. 2, reference numeral 18 denotes an induction heating device. The induction heating device 18 heats the wound body 5 and removes water vapor 19.
Volatilize as. Thus, the moisture contained in the current collector 3 by the spray 14 is removed by heating by the induction heating device 18.

In the present invention, it is desirable to use the water-resistant separator 16. When a conventional non-water-resistant separator (corresponding to the separator 4 in FIG. 8) is used and wound in the same manner using the water-containing current collector 17, the insulating property may be reduced due to the melted current collector material. there were. Further, in the case of a separator having no water resistance, the strength of the separator drops sharply when water is contained, so that the separator sometimes breaks during the winding operation.

As the water-resistant separator, synthetic paper, for example, a paper obtained by subjecting pulp to a water-resistant treatment, a synthetic resin formed into a paper shape, a resin film having pores formed thereon, or the like can be used. As a measure of water resistance,
After sufficient wetting, it is desirable that the material has such a strength that it does not break even if a weight of 50 g or more is hung.

(Second Embodiment) FIG. 3 shows a manufacturing process of an electric double layer capacitor according to a second embodiment. In FIG. 3, reference numeral 20 denotes a power supply. The wound body 5 is configured by winding a plurality of water-containing current collectors 17 and water-resistant separators 16. In the present embodiment, the current collector is wound in a state of containing water, and is dried by Joule heat generated by applying a current to the conductive foil or the current collector.

FIG. 4 shows the result of measurement of the manner in which the wound body 5 of FIG. 3 is heated by Joule heat drying using a thermocouple inserted into the center of the wound body 5. In FIG.
The X axis represents the energization time (minutes), and the Y axis represents the temperature (° C.) at the center of the wound body 5. In FIG. 4, the black dots are the results of Joule heat drying corresponding to the second embodiment. The open circles are the results of a conventional drying example for comparison and heating with an external heater. Heated products can be heated to room temperature +
Although the temperature is about 50 ° C., the center temperature obviously exceeds 100 ° C., which is the boiling point of water, over 10 minutes after energization. The thus dried product has a residual water content of 10 pp in the current collector.
m or less, and there was no problem with residual moisture.

In this experiment, the current may be DC or AC. On the other hand, in the conventional drying, the energization time is 100
It is still several tens of degrees Celsius even in minutes, and it is expected that water containing water still remains inside the current collector. In other words, it is considered that even when heating is performed from the outside with infrared rays or the like, heat is not easily transmitted to the inside of the wound body 5. In the sample dried with Joule heat, steam 19 was applied to the wound body 5 as shown in FIG.
It blew up white from the upper and lower surfaces. This water vapor 19 is considered to be the water content of the current collector 17 containing water inside the wound body 5.
During this experiment, steam 19 did not blow out from the side surface of the wound body 5. This is probably because the conductive foil 2 functioned as a barrier. By programming the applied voltage and current value in advance, the evaporation rate of water can be set freely so as not to damage the current collector due to excessive generation of water vapor, or according to the amount of generated water vapor. Power supply 20
There is no problem whether the current supplied from the DC or the DC is supplied.

(Embodiment 3) FIG. 5 shows a manufacturing process of an electric double layer capacitor according to Embodiment 3. In FIG. 5, reference numeral 21 denotes an eddy current generator. The wound body 5 is formed by winding a plurality of water-containing current collectors 17 and a plurality of water-resistant separators 16. In the present embodiment, the current collector is wound in a state of being hydrated, an eddy current is generated on the conductive foil or the conductor by an external eddy current generator 21, and the hydrated current is generated by the heat generated by the eddy current. The electric body 17 is dried.

(Fourth Embodiment) FIG. 6 shows a process of manufacturing an electric double layer capacitor according to a fourth embodiment. In FIG. 6, a plurality of wound bodies 5 are formed together with a hydrated current collector 17 and a water-resistant separator 16, with gaps 22 formed therebetween.
That is, it is configured to be wound in a loosely wound state.
By loosely winding in this way, water is more likely to evaporate than the water-containing current collector 17.

By making the separator 16 hydrate in addition to the current collector 17, it is easy to make the water content of the hydrated current collector 17 uniform.

(Fifth Embodiment) FIG. 7 shows a manufacturing process of an electric double layer capacitor according to a fifth embodiment. In FIG. 7, 23 is a current collector after drying, and 24 is a winding device. When the current collector wound in a water-containing state is dried, a gap 22 may be formed between the current collector and the separator. This phenomenon is the opposite phenomenon in which the current collector 3 in FIG. The dried current collector 23 having the gaps 22 formed as described above is hard-wound by the winding device 24 as shown by the arrow, and the outer diameter thereof can be reduced. The capacity density is increased and automatic insertion into the case becomes easier.

In the case of drying a water-containing wound body or separator, the drying time can be shortened and the product cost can be reduced by using such a drying method in combination. In addition, by impregnating the conductive foil, when the surface of the current collector is exposed by rubbing the surface of the current collector to attach the extraction electrode to the conductive foil, powder of the current collector is less likely to be generated. It becomes difficult to be caught between them, and it becomes possible to prevent the impedance from becoming unstable when caught. In addition, the working environment can be improved because the powder of the current collector hardly flies.

When water is sprayed on the current collector, it is desirable to slowly increase the water content in the current collector coating in a fine mist. When a large water droplet adheres to the current collector coating, that portion locally swells, which may cause cracks and cracks. Also, even when the current collector is thick, if the current collector is rapidly immersed in a large amount of water, a difference in density occurs between the upper and lower portions of the coating film, which may cause cracks and cracks.

In the case where the current collector 17 containing water is dried while being kept in the case, the case itself may be heated. Further, even when a plurality of drying methods described in this embodiment are used at the same time, or in combination with vacuum drying or the like, more efficient drying can be performed.
In the present invention, the main drying is performed after being wound, and the polymerization and curing of the resin and the like contained in the current collector can also be performed at this time. In the present invention, the current collector is dried in a rolled state, and depending on the type of the resin contained in the current collector, heat polymerization and heat curing are performed. That is, depending on the case, if the current collector is stretched straight, cracks or cracks may occur in the current collector. However, in the case of the wound type electric double layer capacitor manufactured in the present invention, the wound state in the wound state is in a natural state, that is, a state in which the stress is the smallest, so that long-term reliability and aging. Is considered to be a more advantageous direction.

[0046]

As described above, according to the present invention, the current collector is formed into a predetermined shape in a state where the current collector is made hard to be broken, and then dried to obtain a wound body or a laminate having a small amount of resin. Even at the time of preparation, the generation of internal stress in the current collector coating film is minimized, and the coating film is less likely to be cracked or peeled, thereby improving the yield and reliability of the product.

[Brief description of the drawings]

FIGS. 1A and 1B show a part of a method for manufacturing an electric double layer capacitor according to an embodiment of the present invention;

FIG. 2 is a diagram showing a state in which moisture is removed from a wound body including a current collector containing water and a separator.

FIG. 3 is a diagram showing a manufacturing process of the electric double layer capacitor according to the second embodiment.

FIG. 4 is a diagram showing a state in which a wound body is heated by Joule heat drying.

FIG. 5 is a diagram showing a manufacturing process of the electric double layer capacitor according to the third embodiment.

FIG. 6 is a diagram showing a manufacturing process of the electric double layer capacitor according to the fourth embodiment.

FIG. 7 is a diagram showing a manufacturing process of the electric double layer capacitor according to the fifth embodiment.

FIG. 8 is a structural diagram of a wound electric double-layer capacitor for large electric power from 10F (farad) to several thousand F;

FIGS. 9A, 9B, and 9C are explanatory diagrams showing an example of a method for evaluating winding property. FIGS.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case 2 Conductive foil 3 Current collector 4 Separator 5 Winding body 6 Extraction electrode 7 Sealing material 8 Terminal 9 Round bar 10 Breaking surface 11 Fine crack 12 Normal surface 13 Raw material 14 Spray 15 Water 16 Water-resistant separator 17 Water-containing separator 17 Electric body 18 Induction heating device 19 Water vapor 20 Power supply 21 Eddy current generator 22 Gap 23 Current collector after drying 24 Winding device

Claims (8)

[Claims] 1. A method in which activated carbon and a conductivity-imparting agent are applied on one or both sides of a resin as a current collector to a plurality of conductive foils having a thickness of 100 μm or more through one or a plurality of water-resistant separators. An electric double-layer capacitor wound and enclosed in a predetermined non-aqueous electrode solution together with an extraction electrode. 2. A plurality of conductive foils coated with activated carbon and a conductivity-imparting agent on one side or both sides of a resin as a current collector with a thickness of 100 μm or more are wound through a separator and taken out into a non-aqueous electrode solution. In an electric double layer capacitor encapsulated with electrodes, the current collector is hydrated and wound while the current collector is dried, then taken out into a predetermined non-aqueous electrode solution, and encapsulated with an electrode. Method. 3. A plurality of conductive foils coated with activated carbon and a conductivity-imparting agent on one side or both sides of a resin as a current collector with a thickness of 100 μm or more are wound through a separator and taken out in a non-aqueous electrode solution. In the electric double layer capacitor encapsulated with the electrodes, the current collector is wound in a state of being hydrated, and then a current is applied to the conductive foil or the current collector to generate heat, and the current collector is dried. A method for producing an electric double layer capacitor which is enclosed in a non-aqueous electrode solution together with an extraction electrode. 4. A plurality of conductive foils, each coated with activated carbon and a conductivity-imparting agent on one side or both sides of a resin as a current collector with a thickness of 100 μm or more, are wound through a separator and taken out into a non-aqueous electrode solution. In the electric double-layer capacitor encapsulated with the electrodes, the current collector is dried by applying an electromagnetic field from outside so as to generate eddy current in a state of being hydrated and wound, and then drying the current collector. A method for manufacturing an electric double layer capacitor which is taken out of an electrode solution and sealed together with an electrode. 5. A plurality of conductive foils coated with activated carbon and a conductivity-imparting agent on one or both sides of a resin as a current collector with a thickness of 100 μm or more are wound through a separator and taken out into a non-aqueous electrode solution. In the electric double layer capacitor encapsulated with the electrodes, the current collector is hydrated, heated and dried in a state where the current collectors are wound with a gap formed between the current collectors, and then taken out into a predetermined nonaqueous electrode solution. A method of manufacturing an electric double layer capacitor to be enclosed with electrodes. 6. A plurality of conductive foils each coated with activated carbon and a conductivity-imparting agent on one or both sides of a resin as a current collector with a thickness of 100 μm or more are wound through a separator and taken out into a non-aqueous electrode solution. In an electric double layer capacitor sealed with electrodes, after the current collector is wound in a state of being hydrated, the current collector is dried by vacuum drying, and then taken out into a predetermined non-aqueous electrode solution and sealed with an electrode. Of manufacturing electric double layer capacitors. 7. A plurality of conductive foils having activated carbon and a conductivity-imparting agent applied on one or both sides of a resin as a current collector to a thickness of 100 μm or more are wound through a separator and taken out into a non-aqueous electrode solution. In the electric double layer capacitor encapsulated with the electrodes, the current collector is wound while being hydrated, then the current collector is dried, and a jig is inserted into a central portion of the current collector, and the current collector is inserted. A method for manufacturing an electric double-layer capacitor in which is wound into a predetermined non-aqueous electrode solution and sealed together with an electrode after winding to a predetermined size. 8. A plurality of conductive foils each coated with activated carbon and a conductivity-imparting agent on one side or both sides of a resin as a current collector with a thickness of 100 μm or more are wound through a separator and taken out into a non-aqueous electrode solution. In an electric double layer capacitor sealed with electrodes, the current collector is wound together with a water-containing separator, and after the separator and the current collector are dried, the electric double layer is taken out into a predetermined non-aqueous electrode solution and sealed with an electrode. Manufacturing method of capacitor.