JPH0278213A - Electric double layer capacitor - Google Patents

Abstract

PURPOSE:To discharge a large electric current by a method wherein, in an electric double layer capacitor which uses activated carbon as polarization electrodes and utilizes an electrolyte, polarization electrode faces composed of an activated carbon fiber are covered with continuous conductive metal layers and a gap of the polarization electrodes is filled with a metal linked to the metal layers in order to form an electrode body. CONSTITUTION:Polarization electrodes 2 composed of a cloth of a phenol-based activated carbon fiber are set to a compressed state; this cloth is filled with aluminum conductive metals 3 by using a hot-press; it is stamped to be a disk shape; an electrode body is formed. Then, this electrode body is impregnated with an electrolyte where 10weight% of tetraethylammonium tetrafluoroborate has been added to propylene carbonate; after that, a separator 4 is laid in between; the electrodes are piled up. After that, they are sandwiched between a stainless steel cases 1 ; an opening end is sealed by using a gasket 1a. Thereby, an internal resistance of the polarization electrodes is lowered, and an area coming into contact with the electrodes of the conductive metals is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an electric double layer capacitor using activated carbon as a polarizable electrode and an electrolyte.

BACKGROUND OF THE INVENTION Conventionally, the electric FM body of this type of electric double layer capacitor has been made by press-molding activated carbon particles or by coating the mixture with a suitable binder on a metal current collector. In addition, when activated carbon fibers are used, a thermally sprayed layer of aluminum is formed on the activated carbon fibers, and the electrode body is constructed by welding the electrode case made of strong stainless steel as the case material and the thermally sprayed layer of aluminum. .

Problems to be Solved by the Invention In such conventional electric double layer capacitors, the movement of charges when they are accumulated or released between the electrodes and the electrolyte, that is, when charging or discharging, the electric double layer The value of the internal resistance that goes in series with the multilayer capacitor has a large effect. For example, when charging at a constant voltage, it takes a long time to complete charging because the internal resistance is large. In addition, even when discharging at a large current, the internal resistance causes a large voltage drop and the capacitance of the electric double layer capacitor is not utilized, so there are problems in that the practical use of the capacitor is limited.

The present invention solves these problems and aims to lower the internal resistance.

Means for Solving the Problems In order to solve the above problems, the present invention provides a method in which at least one side of a polarizable electrode made of an aggregate of activated carbon fibers or an activated carbon fiber cloth is covered with a continuous conductive metal layer, The electrode body is constructed by filling the gap between the polarizable electrodes with the conductive metal so as to be connected to the metal layer.

Effect: According to the configuration of the present invention, the internal resistance in the thickness direction is improved by filling the gap between the polarizable electrodes with conductive metal. Therefore, when charging or discharging, as shown in FIG. 2, the polarizable electrode is compressed because it acts from the capacitance C1 of the portion R1 of the polarizable electrode with low electrical resistance, that is, the portion close to the conductive metal. Furthermore, when filled with conductive metal, the capacity of the portions with low electrical resistance increases, allowing for faster charging and discharging of large currents.

Example Hereinafter, one embodiment of the present invention will be described using the drawings.

As shown in Fig. 1, the conductive aluminum was The electrode body formed by filling the metal 3 with the hot press method is punched out into a disk shape with a diameter of 2 cm using a punching die.

After adding 10 wt% of tetraethylammonium tetrafluoroborate to propylene carbonate to this electrode body and impregnating it with an electrolytic solution, the electrode body is stacked with a separator 4 interposed between them, and this is further sandwiched between stainless steel cases 1. Gaskera) 12L is placed at the open end of the opening, and the opening is sealed by caulking.

FIG. 3 shows the charging characteristics of the electric double layer capacitor according to the present invention when 2V is applied. For comparison, we also show the characteristics of a prototype of a conventional structure in which aluminum was formed on only one side of the polarizable electrode by plasma spraying. As is clear from the figure, the charging time of the product of the present invention is shorter than that of the conventional product.

It should be noted that the polarizability 'F! The L pole must be exposed.

Furthermore, in order to obtain the same effect by forming the conductive metal only on one side of the polarizable electrode as in the conventional method, it is possible to obtain the same effect by reducing the thickness of the polarizable electrode and increasing the contact surface with the conductive metal. However, due to product size constraints, it is not possible to increase the size unnecessarily. Therefore, in view of these constraints, it is appropriate to compress the polarized electrode and fill it with conductive metal.

Further, in this embodiment, the polarizable electrode was constructed from a cloth made of activated carbon fibers, but it may be constructed from a collection of felt-like activated carbon fibers other than cloth-like ones.

Effects of the Invention As described above, the present invention lowers the internal resistance of polarizable electrodes,
By efficiently increasing the area where the conductive metal contacts the polarizable electrode, it is possible to easily obtain an electric double layer capacitor with low internal resistance that can be rapidly charged and discharged with a large current.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing one embodiment of the electric double layer capacitor of the present invention. Fig. 2 is an explanatory diagram of the anode side electrode. Fig. 3 shows the charging characteristics of the inventive product and the conventional product when 2V is applied. It is a characteristic diagram. 1... Case, 2... Polarizable electrode, 3
... Conductive gold M, 4... Separator. Name of agent: Patent attorney Shigetaka Awano and 1 other person! −
Case 4 - Sepa ν Ichiyo Figure 1 C1 ~ α-L Capacity 12 Figure 3 Katsuihoko ■ Self-

Claims (3)

[Claims] (1) An electrode body is constructed by covering at least one side of a polarizable electrode made of activated carbon fiber with a continuous conductive metal layer, and filling the gap between the polarizable electrodes with a metal connected to the metal layer. double layer capacitor. (2) The electric double layer capacitor according to claim 1, wherein the conductive metal is at least one selected from valve metals such as Al, Ta, Ti, and Hb. (3) The electric double layer capacitor according to claim 1, wherein the polarizable electrode is compressed and fixed by a conductive metal.