Isuzu Motors Limited

Yoriaki Niida

Yoshinobu Tsuchiya

Ken Kurabayashi

Akio Yoshida

Hitoshi Koizumi

Akihiro Shirata

Hiroyoshi Moroboshi

Seiichiro Kitou

Seiichiro Kito

Tadakuni Nishitani

Fine powder particles of an electrically conductive or semiconductive material, which have a diameter of 10 .mu.m or less, are pressurized, and at the same time, a pulse voltage is applied between the fine powder particles to produce an electric discharge therebetween. The fine powder particles are fused together at areas where they contact each other, thereby producing a porous sintered body. The porous sintered body is made of only an electrically conductive or semiconductive material without using any particle binders whatsoever.

Porous sintered body and method of manufacturing same

An electric double which utilizes the principles of an electric double layer in the interface between polarized electrodes and an electrolyte, each of the polarized electrodes being composed of minute active carbon particles of coal tar which have a specific surface area ranging from 1,000 to 4,000 m.sup.2 /gram. Many such minute active carbon particles are packed in a unit volume for an increased electrostatic capacitance.

Electric double layer capacitor

An electric double layer capacitor has an electric double layer composed of an interface between activated carbon and electrolyte. The electric double layer capacitor includes a pair of polarized electrodes each comprising an electrode body in the form of a porous sintered body of joined active carbon particles. When the electrode body is sintered, an electrically conductive layer is formed on a surface of the electrode body. With this construction, the contact resistance between the electrode body and a current collector through the electrically conductive layer is reduced, so that the electric double layer has a reduced internal resistance.

An electric double layer capacitor has two polarized electrodes each comprising a porous sintered body, and two current collectors each made of an electrically conductive material composed of a base and electrically conductive fine particles mixed in the base. The current collectors are held in contact with surfaces of the polarized electrodes and enter pores of the polarized electrodes.

An electric double layer capacitor employs a paste electrode between collector electrodes. The paste electrode is compressed under small load because the collector electrodes are pressed by compression plates in only an area corresponding to the past electrode. With the paste electrode thus compressed, the internal resistance of the capacitance is reduced and the capacitance of the capacitor is stable. The electric double layer capacitor comprises a stack of basic cells of capacitor elements. The basic cells are held closely together by a bolt which extends through central holes in the basic cells and interconnects the compression plates, so that the basic cells are compressed under a uniform and appropriate pressure.

In producing an electrical double-layer capacitor cell, when the polarizing electrode (61,71) is formed by sintering to the collecting electrode (11,21) obtained by sintering a conductive powder into plate-like form, the contact resistance between the collecting electrode (11,21) and the polarizing electrode (61,71) becomes extremely small. Thereby, the internal resistance of the electrical double-layer capacitor cell becomes small.

Electrical double-layer capacitor

An electrical double-layer capacitor cell wherein a sintered polarizing electrode (2) is used as a polarizing electrode, and the collecting electrode (1) and the sintered polarizing electrode (2) are contacted. Conductive metal evaporated films (5,6) are formed on the respective contact surfaces of the collecting electrode (1) and of the sintered polarizing electrode (2). When the above-described contact is carried out by the respective conductive metal evaporated films (5,6), the contact resistance becomes small.

A gasket (4) or collecting electrodes (1) are used as members for separating the inside from the outside of an electrical double-layer capacitor and small holes (5) are provided therein through which the internal air is drawn. Thus the internal pressure becomes lower than the atmospheric pressure and the pressure difference is generated between the inside and the outside. Due to this pressure difference, collecting electrodes (1) are pressed to solid polarizing electrodes (2). Hence the resistance in the contacts between the collecting electrodes and the solid polarizing electrodes can be reduced. Since the contact force is obtained by the pressure difference between the inside and the outside, the contact force is applied equally to every part of the contacts. As a result, there is no contact where its contact resistance is not reduced. Further, there is no need of provision of any device for generating the contact force outside the electrical double-layer capacitor.

In a forming an electrical double-layer capacitor by combining a plurality of electrical double-layer capacitor cells, the electrical double-layer capacitor cells are formed not by being laminated in a vertical direction but by being arranged in a horizontal direction, thereby allowing a multiplicity of electrical double-layer capacity cells to be arranged even in the case of a narrow space if only there is a sufficient area.

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Yamato, Japan

Yoriaki Niida