JP3160725B2 - Electric double layer capacitor - Google Patents

Abstract

PURPOSE:To sharply reduce the internal resistance of the title capacitor by eliminating a separator, to enhance the performance of the title capacitor and to reduce the production cost of the title capacitor. CONSTITUTION:The title capacitor is formed by providing the following: one pair of polarizable electrodes 3p,... which have been arranged in parallel via an electrolyte solution C; and one pair of conductive electrodes 2p,... which have been connected to outside faces of the individual polarizable electrodes 3p,.... One pair of electrode units 5p,... which have united the conductive electrodes 2p,... and the polarizable electrodes 3p,... are formed. The individual electrode units 5p,... are held in fixed positions by a plurality of insulating bridges 7,... arranged between the individual electrode units 5p, and 5n or by a casing 8 or the like which supports the conductive electrodes 2p, 2p at the individual electrode units 5p, 5n.

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 comprising a pair of polarizable electrodes arranged in an electrolytic solution so as to face each other and a pair of conductive electrodes connected to the outer surface of each polarizable electrode.

[0002]

2. Description of the Related Art Conventionally, an electric double layer capacitor disclosed in Japanese Patent Publication No. 2-5007 has been known as an electric double layer capacitor.

[0003] This type of electric double-layer capacitor includes a pair of polarizable electrodes arranged to face each other in an electrolytic solution and a pair of conductive electrodes connected to the outer surface of each polarizable electrode. A metal material such as aluminum is adhered to each outer end face of a pair of activated carbon fiber cloths constituting the polarizable electrode by spraying or the like, and a separator is arranged between each activated carbon fiber cloth, and the outer end face side of each activated carbon fiber cloth. After disposing a pair of conductive electrodes made of the same metal material as the metal material attached to the case, it is housed in a case while injecting an electrolytic solution. Then, pressure bonding of the polarizable electrode and the conductive electrode is performed by caulking the case. The reason why the metal material is previously adhered by thermal spraying or the like and pressure bonding is performed is to reduce the contact resistance between the polarizable electrode and the conductive electrode.

[0004]

In this type of electric double-layer capacitor, the anode-side polarizable electrode and the cathode-side polarizable electrode are insulated so as not to be in contact with each other, and the second electrode is capable of transmitting ions through the electrolyte. A separator having two functions is required. Generally, a porous sheet formed of polypropylene or the like is used as the separator.
However, since such a separator has a large number of random and non-linear permeation holes, the passage path of ions is substantially lengthened, and the entire permeation area is reduced.
There is a problem that the performance of the capacitor is impaired due to an increase in the internal resistance (internal loss) of the electric double layer capacitor. Further, since it is necessary to reduce the contact resistance between the polarizable electrode and the conductive electrode by pressing, several tens kg / cm ²
A caulking device (special machine) is required to pressurize
There was a disadvantage that the manufacturing cost was high.

The present invention has solved the above-mentioned problems in the prior art. By eliminating the separator, the internal resistance can be greatly reduced, the capacitor performance can be improved, and the manufacturing cost can be reduced. It is an object of the present invention to provide an electric double-layer capacitor that can be used.

[0006]

According to the present invention, there is provided an electric device comprising a pair of polarizable electrodes disposed in an electrolytic solution C so as to face each other, and a pair of conductive electrodes connected to the outer surface of each polarizable electrode. When forming the multilayer capacitor 1, after the active carbon material such as the active carbon fiber containing at least a thermosetting resin is overlaid on the conductive electrodes 2p and 2n formed of the electrolyte impermeable carbon material M, and the thermocompression molding is performed. By performing carbonization, a pair of electrode units 5p and 5n in which the conductive electrodes 2p and 2n and the polarizable electrodes 3p and 3n are integrated is formed, and each of the electrode units 5p and 5n is connected to a regulating member, for example, each electrode. A plurality of insulating bridges 7 arranged between the units 5p and 5n or the conductive electrodes 2p in each of the electrode units 5p and 5n;
It is characterized in that it is held in a fixed position by a casing 8 or the like supporting 2n.

An electric double layer capacitor 1 according to another embodiment of the present invention comprises conductive electrodes 2p and 2q formed of an electrolyte-impermeable carbon material M, and an activated carbon material containing at least a thermosetting resin. Polarized molded body 3pm
Are bonded by a bonding material B using a thermosetting resin and then carbonized to form conductive electrodes 2p and 2n.
And the polarizable electrodes 3p, 3n are integrated to form a pair of electrode units 5p, 5n.
A regulating member, for example, a plurality of insulating bridges 7 arranged between each electrode unit 5p and 5n or each electrode unit 5p, 5n
n is held in a fixed position by a casing 8 or the like that supports the conductive electrodes 2p and 2n in n.

Further, an electric double layer capacitor 1 according to another embodiment of the present invention comprises a conductive electrode 2p, 2q formed of an electrolyte-impermeable carbon material M, an activated carbon material containing at least a thermosetting resin. After bonding the polarizable electrodes 3p and 3q obtained by molding and carbonizing with an adhesive material B using a thermosetting resin, the adhesive material B is carbonized to obtain a conductive property. A pair of electrode units 5p, 5n integrating the electrodes 2p, 2n and the polarizable electrodes 3p, 3n
And each electrode unit 5p, 5n supports a regulating member, for example, a plurality of insulating bridges 7 arranged between each electrode unit 5p and 5n or the conductive electrodes 2p, 2n in each electrode unit 5p, 5n. It is characterized in that it is held in a fixed position by a casing 8 or the like.

[0009]

According to the electric double layer capacitor 1 of the present invention, for example, the conductive electrode 2p formed from the electrolyte impermeable carbon material M is provided with an activated carbon material such as an activated carbon fiber containing at least a thermosetting resin. After stacking and thermocompression molding,
By performing the carbonization process, an electrode unit 5p (the same is applied to the 5n side) in which the conductive electrode 2p and the polarizable electrode 3p are integrated can be formed. Therefore, the conductive electrode 2 at the time of assembly is
The pressure bonding step between p and the polarizable electrode 3p becomes unnecessary, and each electrode unit 5p and 5n is fixed using, for example, a plurality of insulating bridges 7 (regulating members) disposed between the pair of polarizable electrodes 3p and 3n. Can be held in position. That is, each electrode unit 5
It is possible to assemble with p and 5n held in a fixed position, and a separator disposed between each electrode unit 5p and 5n becomes unnecessary. As a result, a space free of inclusions can be created between the polarizable electrodes 3p and 3n, whereby a shortest distance ion migration path can be secured and the internal resistance can be reduced.

[0010]

Next, preferred embodiments according to the present invention will be described in detail with reference to the drawings.

An electric double layer capacitor 1 according to the present invention comprises:
The electrode unit 5p shown in FIG. 1 is used. The electrode unit 5p is obtained by integrally forming the polarizable electrode 3p on the conductive electrode 2p. Next, a method for manufacturing the electrode unit 5p will be described with reference to a manufacturing process diagram shown in FIG.

First, a thin plate-shaped conductive electrode 2p is formed from an electrolyte-impermeable carbon material M (step 11). Examples of the electrolyte-impermeable carbon material M include high-density isotropic carbon or vitreous carbon belonging to non-graphitizable carbon obtained from thermosetting resins such as cellulose, furfuryl alcohol resin, and phenol aldehyde resin. Can be used.

Activated carbon fibers (or activated carbon fibers and other materials such as rayon, polyacrylonitrile,
Impregnating a thermosetting resin such as a phenolic resin into a mixture of fibers or pulp made from pitch or the like (step 12),
Activated carbon fiber containing thermosetting resin obtained from this,
The conductive electrode 2p obtained from the step 11 is overlaid and thermocompression molded (step 13). As a result, as shown in FIG. 2, the activated carbon fiber containing the thermosetting resin is a thin plate-like polarized side molded body 3 pm
And the size is smaller than the conductive electrode 2p. Therefore, the two-layer intermediate molded body 4pf, in which the polarized side molded body 3pm is integrally overlapped on the conductive electrode 2p and the peripheral edge of the conductive electrode 2p is projected outward by a predetermined width from the polarized side molded body 3pm. obtain.

Then, the intermediate molded product 4p obtained from the step 13
f performs a carbonization process of heating at a temperature at which the electrode function is not deteriorated. As a result, the thermosetting resin in the activated carbon fibers is carbonized to form a so-called C / C composite, and this portion becomes the polarizable electrode 3p (step 14).

Therefore, the polarizable electrode 3p is connected to the conductive electrode 2p.
Is obtained (Step 15).
Since the electrode unit 5p is manufactured in this manner, the contact resistance (internal resistance) between the conductive electrode 2p and the polarizable electrode 3p is reduced. On the other hand, a pair of the obtained electrode units 5p is prepared, and the electric double layer capacitor 1 according to the present invention is assembled (step 16).

In FIG. 1, reference numerals 5p and 5n denote the electrode units thus obtained, which are on the anode side and the cathode side, respectively. In the electrode units 5p and 5n, the polarizable electrodes 3p and 3n are arranged in parallel with each other facing each other, and a plurality of insulating bridges 7 are interposed therebetween. The insulating bridges 7 have the function of insulating the electrode units 5p and 5n by positioning them slightly apart from each other.
Therefore, it is desirable to minimize the contact area of the electrode units 5p and 5n with the polarizable electrodes 3p and 3n from the viewpoint of reducing the internal resistance.

On the other hand, reference numeral 8 denotes a casing, which comprises a side plate portion 8k formed of an insulating material, and end plate portions 8p and 8n formed of a conductive material covering both ends of the side plate portion 8k.
The conductive electrodes 2p, 2n in each of the electrode units 5p, 5n described above are fitted and assembled into notches 9p, 9n formed at one end and the other end of the inner peripheral surface of the side plate portions 8k. Both ends of 8k are end plates 8p, 8n
To close. Thereby, each electrode unit 5p, 5
n is positioned and supported by the casing 8. At the time of this assembly, each electrode unit 5p
And the organic electrolyte C is injected between 5n. Therefore, the entirety is sealed by the side plate portion 8k and the end plate portions 8p and 8n, and the outer surfaces of the conductive electrodes 2p and 2n respectively contact the inner surfaces of the end plate portions 8p and 8n formed of a conductive material. The plate portions 8p and 8n serve as electrode terminal surfaces connected to an external circuit. Thus, the electric double layer capacitor 1 according to the present invention is obtained.

Since the electrode units 5p and 5n are regulated by the casing 8, the insulating bridges 7 may be omitted. When the insulating bridges 7 are not used, any inclusions between the polarizable electrodes 3p and 3n can be eliminated except for the organic electrolytic solution C. FIG. 4 shows the principle configuration of the electric double layer capacitor 1, in which the organic electrolytic solution C permeates the polarizable electrodes 3p and 3n.

Further, by using the electrolyte impermeable carbon material M for the conductive electrodes 2p and 2n in the electrode units 5p and 5n, the withstand voltage can be increased to about 5 volts. That is, the withstand voltage of the electric double layer capacitor is usually determined by the electrolysis potential Ew of water when an aqueous electrolyte is used as the electrolyte as shown in FIG.
It is about 1.7 volts. On the other hand, when an organic electrolytic solution is used, it is determined by the dissolution potential Ed of the electrolytic solution with respect to the metal material used for the conductive electrode. For example, when the metal material is aluminum, the potential Ed is about 2.3 volts. Become. In addition, in the case of the electric double layer capacitor disclosed in the above publication, titanium is adopted as the conductive electrode, whereby
Although the withstand voltage is increased, the withstand voltage that can be secured in this case is about 2.9 volts. However, in the case of the electric double layer capacitor 1 of the embodiment, since the electrolytic solution impervious carbon material M is used, it does not depend on the dissolution potential Ed of the metal material by the organic electrolytic solution when the metal material is used. And the decomposition potential Ec of the organic electrolyte or the anodic oxidation potential Em of the carbon material electrode. These potentials Ec and Em
Is usually about 5 volts, and eventually the withstand voltage can be increased to about 5 volts.

Next, a modified embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

FIG. 6 shows another manufacturing method of the electrode unit 5p. Hereinafter, the manufacturing method will be described with reference to the manufacturing process diagram of FIG.

First, a thin plate-shaped conductive electrode 2p is formed from an electrolyte-impermeable carbon material M in the same manner as in the above embodiment (step 21).

On the other hand, activated carbon fibers (or activated carbon fibers and other materials such as rayon, polyacrylonitrile,
A mixture of fibers or pulp made of pitch or the like as a raw material) is impregnated with a thermosetting resin such as a phenolic resin, and is formed into a thin plate-like polarization for obtaining a polarizable electrode 3p (C / C composite) by thermocompression bonding. Forming side molding 3pm (Step 2)
2).

Next, the conductive electrode 2p obtained from the step 21
And 3 pm of the polarization-side molded body obtained from the step 22 are adhered with an adhesive material B using a thermosetting resin such as a phenolic resin. As a result, an intermediate molded product 4ps substantially the same as the intermediate molded product 4pf in which the conductive electrode 2p and the polarization-side molded product 3p are bonded to each other is obtained (Step 23: see FIG. 2).

Then, the intermediate molded product 4p obtained from the step 23
For s, carbonization is performed by heating at a temperature that does not deteriorate the electrode function. Thereby, both the thermosetting resin and the adhesive material B in the activated carbon fiber are carbonized, so-called C / C
By forming the composite, this portion becomes the polarizable electrode 3p. Therefore, an electrode unit 5p similar to that of the above-described embodiment in which the polarizable electrode 3p is integrally formed with the conductive electrode 2p is obtained (steps 24 and 25).

As another modified embodiment, step 22
By performing the same carbonization treatment as in step 24 on the polarization-side molded body 3pm obtained in the above, a polarizable electrode 3p was manufactured before sticking, and the obtained polarizable electrode 3p and step 21 were obtained. The conductive electrode 2p may be stuck with the sticking material B. In this case, it is necessary to carbonize the adhesive material B again after sticking, but there is an advantage that the conditions of each carbonizing treatment can be set to be optimal.

FIG. 7 shows another structure of the electric double layer capacitor 1 according to the present invention. The electric double layer capacitor 1 shown in the figure has two electric double layer capacitor elements 1x and 1y provided inside a casing 8. in this case,
The structure is the same as the structure in which two electric double layer capacitors shown in FIG. 1 are connected in series, except that the conductive electrode 2c arranged at the center is also used for each of the capacitor elements 1x and 1y.
Therefore, such a structure can be similarly implemented even when three or more electric double layer capacitor elements 1x are used.

The embodiment has been described in detail above.
The present invention is not limited to such an embodiment,
The detailed configuration, material, and the like can be arbitrarily changed without departing from the gist of the present invention.

[0029]

As described above, the present invention provides an electric double layer comprising a pair of polarizable electrodes arranged in parallel via an electrolyte and a pair of conductive electrodes connected to the outer surface of each polarizable electrode. In the capacitor, for example, by laminating an active carbon material such as an active carbon fiber containing at least a thermosetting resin on a conductive electrode formed of an electrolytic solution impermeable carbon material and thermocompression molding, and then performing carbonization treatment, Since a pair of electrode units are formed by integrating a conductive electrode and a polarizable electrode, and each electrode unit is held in a fixed position by a regulating member, the internal resistance (internal loss) is greatly reduced by eliminating the separator. In addition, the capacitor performance can be improved, and the production cost can be significantly reduced by eliminating the crimping step.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an electric double layer capacitor according to the present invention,

FIG. 2 is a perspective view of an electrode unit used for the electric double layer capacitor,

FIG. 3 is a manufacturing process diagram of the electrode unit.

FIG. 4 is a diagram showing the principle configuration of the electric double-layer capacitor,

FIG. 5 is a diagram illustrating the operation of the electric double-layer capacitor,

FIG. 6 is a manufacturing process diagram according to a modified example of the electrode unit,

FIG. 7 is a longitudinal sectional view according to a modified example of the electric double-layer capacitor,

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric double layer capacitor 2p ... Conductive electrode 3p ... Polarizing electrode 3pm Polarization side molded object 5p ... Electrode unit 7 ... Insulating bridge 8 Casing B Adhesive material M Electrolyte impermeable carbon material C Electrolyte (organic electrolyte) )

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-84915 (JP, A) JP-A-4-98811 (JP, A) JP-A-3-80517 (JP, A) 199503 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01G 9/058 H01G 9/016

Claims (9)

(57) [Claims] 1. An electric double-layer capacitor comprising a pair of polarizable electrodes opposed to each other in an electrolytic solution and a pair of conductive electrodes connected to the outer surface of each polarizable electrode. An active carbon material such as an activated carbon fiber containing at least a thermosetting resin is superimposed on a conductive electrode formed from a carbon material, and then thermocompression-bonded, followed by carbonization to integrate the conductive electrode and the polarizable electrode. An electric double layer capacitor comprising: a pair of electrode units formed as described above, wherein each electrode unit is held in a fixed position by a regulating member. 2. The electric double layer capacitor according to claim 1, wherein the restricting member is a plurality of insulating bridges arranged between the electrode units. 3. The electric double-layer capacitor according to claim 1, wherein the regulating member is a casing that supports the conductive electrodes in each electrode unit. 4. An electric double-layer capacitor comprising a pair of polarizable electrodes facing each other in an electrolytic solution and a pair of conductive electrodes connected to the outer surface of each polarizable electrode. After bonding a conductive electrode molded with a carbon material and a polarization-side molded body molded with an activated carbon material such as an activated carbon fiber containing at least a thermosetting resin with an adhesive material using a thermosetting resin, An electric double layer capacitor characterized by forming a pair of electrode units in which a conductive electrode and a polarizable electrode are integrated by carbonizing, and holding each electrode unit in a fixed position by a regulating member. 5. The electric double layer capacitor according to claim 4, wherein the restricting member is a plurality of insulating bridges arranged between the electrode units. 6. The electric double layer capacitor according to claim 4, wherein the regulating member is a casing that supports the conductive electrodes in each electrode unit. 7. An electric double-layer capacitor comprising a pair of polarizable electrodes facing each other in an electrolytic solution and a pair of conductive electrodes connected to the outer surface of each polarizable electrode. A conductive electrode molded from a carbon material, and a polarizable electrode molded from an activated carbon material such as activated carbon fiber containing at least a thermosetting resin, and obtained by carbonization, are pasted together using a thermosetting resin. After bonding with the adhesive, the adhesive is carbonized to form a pair of electrode units integrating the conductive electrode and the polarizable electrode, and each electrode unit is held in place by the regulating member. An electric double layer capacitor characterized by the following. 8. The electric double layer capacitor according to claim 7, wherein the restricting member is a plurality of insulating bridges arranged between the electrode units. 9. The electric double-layer capacitor according to claim 7, wherein the regulating member is a casing that supports the conductive electrode in each electrode unit.