JP2000348976A - Electric double-layer capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electric double-layer capacitor which is constituted of inexpensive members which are not required to be sealed and can reduce the size and height of an electric circuit. SOLUTION: An electric double-layer capacitor is constituted of a positive electrode 1 and a negative electrode 2, both of which are housed in spaces surrounded by a separator 3 and conductive current bodies 4, in a state where the electrodes 1 and 2 are separated from each other by the separator 3 and an electrolyte 6 contained in the spaces, and the current collecting bodies 4 are constituted of anisotropic conductive films. This capacitor is constituted of inexpensive members which are do not require sealing. When this capacitor is used in an electric circuit, additionally, the size and height of the circuit can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electric double layer capacitor.

[0002]

2. Description of the Related Art FIG. 5 is a diagram showing a structure of an electric double layer capacitor called a coin type. In FIG. 5, the electric double-layer capacitor includes a pair of a positive electrode 21 and a negative electrode 22 interposed therebetween to separate the positive electrode 21 and the negative electrode 22 from each other.
3, and a space between a metal container 25 containing an electrolytic solution 26 and a metal lid 24 is sealed via a gasket 29. Positive electrode 21 and negative electrode 22 forming polarizable electrodes
In many cases, sheet-shaped activated carbon fiber or activated carbon powder is punched out and used in the form of pellets. For the coin-type electric double layer capacitor, a caulking sealing method using a sealing material such as a gasket 29 has been adopted.

A large capacitance is realized by a multilayer electric double layer capacitor. FIG. 6 is a diagram showing a structure of a multilayer electric double layer capacitor. The laminated electric double layer capacitor is obtained by rolling a laminated sheet in which a separator 33 is sandwiched between a pair of electrode sheets composed of a positive electrode plate 31 and a negative electrode plate 32, impregnated with an organic electrolyte, and housed in a metal container 35. Make the enclosed structure. The sealing of the multilayer electric double layer capacitor has been performed by a thermocompression bonding method or the like.

[0004]

However, in order to manufacture these electric double layer capacitors, it is necessary to enclose members of the electric double layer capacitor. The encapsulation operation increases the cost of the electric double layer capacitor. Furthermore, the encapsulation structure increases the bulk of the electric double layer capacitor, and an electric circuit incorporating this electric double layer capacitor has a problem that the mounting density increases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electric double layer capacitor which is made of a member which does not need to be sealed at low cost and which can reduce the size and height of an electric circuit.

[0006]

An electric double layer capacitor according to the present invention comprises a polarizer electrode housed in a space surrounded by a separator and a conductive current collector with a separator interposed therebetween, and a space filled with the polarizable electrode. Composed of the deposited electrolyte,
The current collector is formed of an anisotropic conductive film. In the anisotropic conductive film, the conductive part and the insulating part are
It is formed alternately on the surface and continuously in one direction of the surface and the thickness direction.

In the electric double layer capacitor of the present invention,
The separator and the insulating portion of the conductive film are formed using the same material, a material having similar properties, or a material having good compatibility in various characteristics such as workability. Specifically, the electric double-layer capacitor of the present invention, the separator, and the insulating portion of the conductive film, polypropylene and polyethylene, polyethylene and polyethylene terephthalate, polyamide and polyamide imide, and nylon and polyacrylonitrile, It is characterized in that at least one material of the group is used.

[0008] The electric double layer capacitor of the present invention is characterized in that a positive electrode and a negative electrode constituting a polarizable electrode are arranged with their main surfaces facing each other with a separator therebetween.

Further, according to the present invention, an electric double layer capacitor may be constructed in which the positive electrode and the negative electrode constituting the polarizable electrode are arranged with their respective sides facing each other with a separator therebetween. In this case, an electric double layer capacitor in which each of the positive electrode and the negative electrode constituting the polarizable electrode is composed of a plurality is also possible.

According to the present invention, by using an anisotropic conductive film only for a current collector to which a polarizable electrode is connected, it is possible to obtain a configuration in which a terminal voltage can be extracted from only one surface.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

The electric double layer capacitor of the present invention is characterized in that the current collector is formed of an anisotropic conductive film. FIG. 4 is a cross-sectional view schematically showing the structure of the anisotropic conductive film. In the anisotropic conductive film 13, the conductive portions 15 and the insulating portions 14 are formed alternately on the surface and continuously in both the thickness direction and one direction of the surface. Anisotropic conductive film 1
Reference numeral 3 denotes anisotropy having conductivity only in the direction in which the conductive portion 15 and the insulating portion 13 are formed in the plane, and has conductivity through the conductive portion 15 in the thickness direction.

The polarizable electrode of the electric double layer capacitor is manufactured by punching a sheet-shaped electrode material into a predetermined size in the form of a pellet. The sheet-like electrode material is obtained by adding ethanol to a mixture consisting of 80 parts by weight of activated carbon powder (average particle size: 10 μm), 10 parts by weight of carbon black powder, and 10 parts by weight of polytetrafluoroethylene, which has been activated by heat treatment to obtain a slurry. At a temperature of 120 in a nitrogen stream.
It is produced by removing the solvent and moisture by a heat treatment at 4 ° C. for 4 hours. As an alternative to carbon black powder, acetylene black, furnace black, and other metal particles may be used. The polarizable electrode is immersed in an organic electrolyte as a positive electrode and a negative electrode.

As the electrolytic solution, there is a solution in which an electrolyte such as tetraethylammonium tetrafluoroboron is dissolved in a solvent such as an aqueous sulfuric acid aqueous solution or an organic propylene carbonate. For the electric double layer capacitor of the present invention, an organic and electrochemically stable quaternary salt is used.

Further, the separator used for the electric double layer capacitor is required to have good strength, ion permeability, insulation, temperature resistance and the like. As the separator of the electric double layer capacitor of the present invention, butyl rubber, porous propylene, rayon, Manila hemp, various nylons, etc. are suitable.

FIG. 1 is a sectional view of an electric double layer capacitor according to a first embodiment of the present invention. In FIG.
The electric double layer capacitor includes a positive electrode 1 and a negative electrode 2 housed in a space surrounded by a separator 3 and a current collector 4, and an electrolytic solution 6 filled in the space. The positive electrode 1 and the negative electrode 2 are arranged with their respective main surfaces facing each other with a separator 3 therebetween. The positive electrode 1 and the negative electrode 2
Inside the electric double layer capacitor, a conductive binder 5 is adhered to the collecting electrode 4 composed of the anisotropic conductive film 13. If the positive electrode lead 7 and the negative electrode lead 8 are respectively connected to the positive and negative electrode current collectors of the electric double layer capacitor, the terminal voltage can be obtained.

Table 1 is a comparison table of the electric double layer capacitor according to the present embodiment, in which a conventional coin-type electric double layer capacitor is used as a comparative example. Table 1 shows initial capacitance characteristics (F), internal resistance (Ω), and thickness when charged at an applied voltage of 3.0 V and discharged at 0.5 mA (the same applies hereinafter). According to Table 1, the characteristics of the two are almost the same, but the electric double layer capacitor according to the present embodiment is reduced in height, that is, reduced in size.

[0018]

[Table 1]

FIG. 2 is a sectional view of an electric double layer capacitor according to a second embodiment of the present invention. In FIG.
The electric double-layer capacitor has a configuration in which the side surfaces of the positive electrode 1 and the negative electrode 2 are opposed to each other with a separator 3 interposed therebetween.
The positive electrode 1 and the negative electrode 2 are bonded to a current collector 4 formed of an anisotropic conductive film 13 with a conductive binder 5 inside the electric double layer capacitor. Positive electrode 1 forming a polarizable electrode
In addition, since the negative electrode 2 is configured in a planar manner, a thin electric double layer capacitor is realized. Further, the anisotropic conductive film 13 forming the current collector 4 has conductivity only in a direction perpendicular to the paper surface in FIG. 4. Therefore, if the direction of the current collector is selected, the positive electrode lead 7 and the negative electrode The lead 8 can be provided on the same surface of the current collector 4 of the electric double layer capacitor. Therefore, if an anisotropic conductive film is used, a current collector having a current collecting function only needs to be present on the side to which the polarizable electrode is connected, and the other side only needs to have a protecting function. Become.

Table 2 is a comparison table of the electric double layer capacitor according to the present embodiment with a comparative example. According to Table 2, the characteristics are almost the same, but the electric double-layer capacitor according to the present embodiment is reduced in height, that is, reduced in size.

[0021]

[Table 2]

FIG. 3 is a sectional view of an electric double layer capacitor according to a third embodiment of the present invention. The electric double-layer capacitor shown in FIG. 3 is characterized in that each of the positive electrode 1 and the negative electrode 2 arranged with their side surfaces facing each other with the separator 3 interposed therebetween is composed of a plurality. The positive electrode 1 and the negative electrode 2
Inside the electric double layer capacitor, a conductive binder 5 is adhered to a current collector 4 composed of an anisotropic conductive film 13. Since the current collector 4 is made of the anisotropic conductive film 13, the positive electrode lead 7 and the negative electrode lead 8 can be provided on the same surface of the current collector 4 of the electric double layer capacitor.
With this configuration, a high terminal voltage or large capacity electric double layer capacitor can be obtained.

Table 3 is a comparison table of the electric double layer capacitor according to the present embodiment with a comparative example. According to Table 3, in the electric double layer capacitor according to the present embodiment, the height is reduced, that is, the size is reduced while the initial capacitance characteristics are increased.

[0024]

[Table 3]

It should be noted that an electric double layer capacitor in which a plurality of pairs of the main surfaces of the positive electrode and the negative electrode opposed to each other with a separator interposed therebetween may be arranged in a plane. The present invention also enables a plurality of positive electrodes and negative electrodes to be constructed three-dimensionally with a separator therebetween.

[0026]

As described above, according to the electric double-layer capacitor of the present invention, the electric double-layer capacitor is made of a low-cost member that does not need to be encapsulated. Brings downsizing and low profile to the circuit.

[Brief description of the drawings]

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

FIG. 2 is a sectional view of an electric double layer capacitor according to a second embodiment of the present invention.

FIG. 3 is a sectional view of an electric double layer capacitor according to a third embodiment of the present invention.

FIG. 4 is a cross-sectional view schematically illustrating a structure of an anisotropic conductive film.

FIG. 5 is a diagram showing a structure of a coin-type electric double layer capacitor.

FIG. 6 is a diagram showing a structure of a multilayer electric double layer capacitor.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 positive electrode 2 negative electrode 3 separator 4 current collector 5 conductive binder 6 electrolytic solution 7 positive electrode lead 8 negative electrode lead 13 anisotropic conductive film 14 insulating portion 15 conductive portion 21 positive electrode 22 negative electrode 23 separator 24 metal lid 25 metal Container 26 Electrolyte 29 Gasket 31 Positive electrode plate 32 Negative electrode plate 33 Separator 34 Positive terminal 35 Metal container 39 Gasket

Claims (10)

[Claims] 1. An electric double layer comprising a polarizable electrode housed in a space surrounded by a separator and a conductive current collector with a separator interposed therebetween, and an electrolyte filled in the space. In the capacitor, the current collector includes:
An electric double-layer capacitor comprising an anisotropic conductive film. 2. The anisotropic conductive film is characterized in that conductive portions and insulating portions are formed alternately on a surface and continuous in a thickness direction and one direction of the surface. Claim 1
The electric double-layer capacitor as described. 3. The electric double layer capacitor according to claim 1, wherein the separator and the insulating portion of the conductive film each include one of polypropylene and polyethylene. 4. The electric double layer capacitor according to claim 1, wherein the separator and the insulating portion of the conductive film each include one of polyethylene and polyethylene terephthalate. 5. The electric double-layer capacitor according to claim 1, wherein the separator and the insulating portion of the conductive film each include one of polyamide and polyamide-imide. 6. The electric double-layer capacitor according to claim 1, wherein the separator and the insulating portion of the conductive film each include one of nylon and polyacrylonitrile. 7. The positive electrode and the negative electrode constituting the polarizable electrode are arranged with their respective main surfaces facing each other with the separator therebetween.
An electric double layer capacitor according to claim 6. 8. The positive electrode and the negative electrode constituting the polarizable electrode are arranged so that their respective sides are opposed to each other with the separator therebetween.
An electric double layer capacitor according to claim 6. 9. The polarizer according to claim 8, wherein the polarizable electrode comprises a plurality of positive and negative electrodes.
The electric double-layer capacitor as described. 10. The electric double layer capacitor according to claim 8, wherein only the current collector to which the polarizable electrode is connected is made of the anisotropic conductive film.