JPH0594925A - Electric double layer capacitor - Google Patents

Abstract

PURPOSE:To lessen internal resistance by a method wherein the surface of the lead or the lead alloy as the current collecting body, which comes in contact with a polarizable electrode, is coated with conductive resin, the current collecting body is put in the polarizable electrode, and a solution mainly composed of sulfuric acid is used as an electrolyte. CONSTITUTION:A current collecting body, which comes in contact with a polarizable electrode consisting of activated charcoal 2, is a lead lattice-formed body, and the surface of the lead lattice-formed body 3 is coated with conductive resin 4 consisting of the mixture of graphite and epoxy resin. Sulfuric acid, of 40% is infiltrated into the pores of the activated charcoal 2. After an electric double layer capacitor has been constructed using four polarizable electrodes 1, with a current-collecting body, and three separators 7, a lead terminal 5 is formed. Also, each of the current-collecting body attached polarizable electrodes is welded by lead connecting piece 6. As a result, a large type electric double-layer capacitor, having small internal resistance, can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large-sized electric double layer capacitor using lead or lead alloy as a current collector.

[0002]

2. Description of the Related Art A conventional electric double layer capacitor is 1F
Most of them were small. Therefore, the polarizable electrode also had a diameter of 30 mm and a thickness of 1 mm or less. None of the polarizable electrodes played a role of current collection, and the current collector was arranged at the end of the polarizable electrode.

Lead, which is an inexpensive metal capable of withstanding sulfuric acid, cannot be used as a current collector of an electric double layer capacitor because an insulating film is formed on its surface. Therefore, in a system using sulfuric acid as an electrolytic solution, a conductive rubber film is used as a current collector.

FIG. 4 is a diagram showing a polarizable electrode of a conventional electric double layer capacitor. (11) is a conductive rubber film, (12) is a gasket, (13) is activated carbon, and (14) is a separator.

[0005]

Conventionally, a conductive rubber film, which is easily deformed, is used for the current collector, so that the polarizable electrode is deformed and a large electric double layer capacitor (for example, 1000
It was difficult to make F).

Further, since there is no collector in the polarizable electrode, there is a drawback that the internal resistance becomes large even if the size is large.

[0007]

In the electric double layer capacitor according to the present invention, a conductive resin is applied to the surface of lead or a lead alloy as a current collector in contact with the polarizable electrode, and the polarizable electrode is coated with the conductive resin. It is characterized in that a solution containing a current collector and containing sulfuric acid as a main component is used as an electrolytic solution.

[0008]

In the present invention, by applying a conductive resin to the surface of lead or a lead alloy, it is possible to use lead or a lead alloy which could not be used as a current collector of an electric double layer capacitor using sulfuric acid as an electrolytic solution. To do.

Lead or a lead alloy coated with a conductive resin is a rigid body unlike the conductive rubber film, and does not deform even if it is large. Further, since the current collector is put in the polarizable electrode, the internal resistance is small even if it is large.

Further, according to the present invention, by using a carbon material such as carbon black, graphite or acetylene black as the conductive agent of the conductive resin, the adhesion with the activated carbon, which is a polarizable electrode, is improved. However, the internal resistance does not increase.

[0011]

FIG. 1 shows an embodiment of the present invention.

(1) is a polarizable electrode with a current collector according to the present invention. (2) is the activated carbon of the polarizable electrode, (3)
Is a lead grid of the current collector. A conductive resin (4) made of a mixture of graphite and an epoxy resin is applied to the surface of the lead grid (3). The pores of activated carbon are soaked with 40% sulfuric acid.

2 and 3 show an electric double layer capacitor assembled by using four polarizable electrodes (1) with a current collector and three separators (7). )
Is a terminal made of lead. (6) is a lead connecting piece for connecting the polarizable electrodes with the collector. Leads are joined by welding.

In this embodiment, a grid-shaped body as a current collector is used, but another shape, for example, a plate-shaped body may be used.

[0015]

The present invention does not use a conductive rubber film as a current collector as in the prior art, but instead uses lead or a lead alloy coated with a conductive resin on the surface thereof. With the condenser, an electric double condenser with a small internal resistance can be obtained.

Further, the welding of lead serving as a current collector is extremely simple, and the processing time for joining the connecting pieces, terminals, etc. can be greatly shortened.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a polarizable electrode with a current collector according to the present invention.

FIG. 2 is a conceptual diagram of an electric double layer capacitor using a polarizable electrode with a current collector of the present invention.

FIG. 3 is a conceptual diagram of an electric double layer capacitor using a polarizable electrode with a current collector of the present invention.

FIG. 4 is a diagram showing a polarizable electrode of a conventional electric double layer capacitor.

[Explanation of symbols]

 2 Activated carbon 3 Lead grid 4 Conductive resin

Claims (1)

[Claims] 1. A current collector in contact with a polarizable electrode is lead or a lead alloy whose surface is coated with a conductive resin. The current collector is contained in the polarizable electrode, and the electrolytic solution is An electric double layer capacitor, which is a solution containing sulfuric acid as a main component.