JP2000012407A - Electric double-layer capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make satisfactory electric contact between electrodes and to attain improvement in workability. SOLUTION: For the electric double-layer capacitor constituted by piling up a polarized electrode 3, a collector electrode 2 and a separator 4 and having an electrolyte impregnated, at least the polarized electrode 3 and collector electrode 2 are sewn by a sewing thread 1, integrated, further made mulfilayered while including the separator 4 sewn by the sewing thread 1 to be integrated.

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 obtained by stacking a polarizable electrode, a collector and a separator and impregnating the same with an electrolytic solution.

[0002]

2. Description of the Related Art A conventional electric double layer capacitor has a capacitance several orders of magnitude higher in capacitance density than an aluminum electrolytic capacitor having a withstand voltage of the same level. However, from the viewpoint of the amount of energy that can be stored, the electric double layer capacitor is compared with the lead battery, which is a typical secondary battery, in 1993.
Electricity per weight that can be stored at the time of year is about 1 /
It was about 20. Further, the electric double layer capacitor has a property of being able to efficiently charge and discharge energy in a short period of time due to the principle of physical power storage, and has a very advantageous point as compared with a secondary battery.

Paying attention to the point that this electric double layer capacitor is more advantageous than a secondary battery, in an application requiring rapid charging and discharging such as an electric vehicle, for example, the capacitor is connected in parallel with the battery. Research is being carried out in various fields on the so-called battery assist technology to be used and on the electric double layer capacitors with low internal resistance, which are called for power use. In addition to these studies, it has become possible to manufacture electric double-layer capacitors with a much higher energy density than before (for example, Dio Okamura: Basic Research on Power Storage Devices, The Institute of Electrical Engineers of Japan, Journal Vol.115B). No.5, p504-510,
1995) Further, by combining this electric double layer capacitor and an electronic circuit, it has become possible to manufacture a power storage device having a performance exceeding that of a lead battery.

FIG. 4 is a diagram for explaining a single-cell electric double layer capacitor, FIG. 5 is a diagram for explaining a pressing force applied to a single cell, 21 is a collector, and 22 is a polarizable electrode. , 23 is a separator, 24 is a cell, 25 is a cell container,
26 denotes a push plate, and 27 denotes an electrolytic solution.

As shown in FIG. 4, an electric double layer capacitor is composed of a collector electrode 21 made of aluminum foil or the like, a polarizable electrode 22 synthesized by kneading activated carbon and a conductive material, and a separator 23 made of non-woven fabric or resin. 21-Polarizable electrode 22-Separator 23-Polarizable electrode 22-Collecting electrode 2
A single cell 24 is formed by stacking in the order of 1. Then, as shown in FIG.
Through the step of impregnating 7, the capacitor is completed as an electric double layer capacitor.

In an electric double layer capacitor, the polarizable electrode 2
2 (carbon electrode), aluminum collector electrode 21 and various manufacturing techniques to improve the interparticle contact in the carbon electrode and to maintain good mutual electrical conductivity between polarizable electrode 22 and collector electrode 21. It is required, and a device for lowering the internal resistance is required. For example, in order to improve mutual electrical conductivity between the polarizable electrode 22 and the collector electrode 21, a non-electrically conductive oxide film formed on the surface of the collector electrode 21 is chemically or mechanically removed. That has been done. On the electrode surface, as shown in FIG. 5, a pressing force is applied in a direction perpendicular to the pressing plate 26. In many cases, a certain mechanical pressing force is applied in the laminating direction of the capacitor (between the electrodes). ing.

[0007] For example, when the mutual electrical conductivity between the polarizable electrode 22 and the collector electrode 21 is insufficient, the electrical internal resistance of the completed device is large, causing Joule heat to be generated during operation, and as a result, the life is shortened. In addition to reducing the energy efficiency of charging and discharging. Sufficiently good electrical contact between the polarizable electrode and the collector electrode, even for capacitors that emphasize fast time response, or at the expense of high capacitance, for example, capacitor cells for load leveling electrical storage Is the key to performance.

[0008]

However, even if a hot roll press method is used, the degree of mechanical compression between the polarizable electrode and the collector electrode is reduced due to the inherent elasticity of the polarizable electrode itself. Never rises. That is, in order to improve the electrical conductivity, it is necessary to completely introduce another dedicated technology. Also,
In the case where the pressing plate 26 shown in FIG.
If the pressing plate 26 is thin, the load will not be uniform depending on how the pressing pressure is applied, for example, if the pressing plate 26 is thin, and the performance will deteriorate due to the uneven contact pressure between the electrodes. Therefore, it is extremely important to equalize the contact pressure when stacking electric double layer capacitors in order to realize an efficient multilayer electric double layer capacitor.

Regarding the assembling process as described with reference to FIG. 4, the workability is extremely poor because the respective constituent members such as the polarizable electrodes are thin plates, whether manually or mechanically. It is the current situation.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and aims at improving the electrical contact between electrodes and improving the workability.

[0011] For this purpose, the present invention provides an electric double layer capacitor in which a polarizable electrode, a collecting electrode, and a separator are stacked and impregnated with an electrolytic solution, wherein at least the polarizable electrode and the collecting electrode are sewn and integrated with a sewing thread. In addition, a multi-layered structure including a separator is sewn with sewing thread and integrated.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of an electric double layer capacitor according to the present invention, and FIG. 2 is a diagram for explaining an example of sewing and integration of a multi-layered electric double layer capacitor. In the figure, 1 is a sewing thread, 2 is a collecting electrode, 3 is a polarizable electrode, and 4 is a separator.

In the electric double layer capacitor according to the present invention, as shown in FIG. 1, the collector electrode 2, the polarizable electrode 3, and the separator 4 are sewn with sewing thread 1 to be integrated. In the case of a multi-layered electric double layer capacitor, as shown in FIG. 2, a separator 4-a polarizable electrode 3-a collecting electrode 2-a polarizable electrode 3-a separator 4 are sequentially laminated, and the
And integrated.

The sewing thread 1 is made of a thread material which is chemically stable in relation to the electrolytic solution. In addition, the collecting electrode 2
Generally, for example, aluminum chemically treated for the purpose of removing an oxide layer and roughening is used. The polarizing electrode 3 is usually manufactured by, for example, a kneading and roll pressing method. The separator 4 is generally of a nonwoven fabric type such as cellulose or polymer fiber having good electrical conductivity and good ion flowability. In the case of (2), a folded shape can be used.

FIG. 3 is a view showing an example of housing a case of a sewn multilayer electric double layer capacitor, wherein 11 and 12 are sewing units, 13 is a collecting electrode, 14 is a polarizable electrode, 15 is a separator, and 16 is an electrolytic unit. The liquid, 17 indicates a case, and 18 indicates a lead line.

As described above, the collector electrode 2, the polarizable electrode 3, and the separator 4 are sewn and integrated with the sewing thread 1, so that the electric double layer capacitor according to the present invention has
Since a mechanical pressure can be applied to the entire plane of the electrode, the electrical contact between the collector electrode 2 and the polarizable electrode 3 can be improved, and the contact pressure between the electrodes can be made uniform. Further, a fine "sewing hole group" is formed by sewing with the sewing thread 1, so that the "sewing hole group" can have a role of "electrolyte passage" in the electrolyte impregnation step. Therefore, as shown in FIG. 3, the collector electrode 13, the polarizable electrode 14,
A sewing unit 11 in which the separator 15 is sewn and integrated,
The electrolytic solution impregnating step of accommodating 12 in the case 17 and impregnating the electrolytic solution can be shortened. The sewing unit 11 corresponds to the unit described in FIG. 1, and the sewing unit 12 corresponds to the unit described in FIG.

The present invention is not limited to the above embodiment, but can be variously modified. For example, in the above embodiment, one set of the collecting electrode, the polarizable electrode, and the separator were sewn with sewing thread, but these were repeatedly overlapped to form a plurality of sets, that is, a plurality of layers, which were sewn with sewing thread. They may be integrated.

[0018]

As is apparent from the above description, according to the present invention, in an electric double-layer capacitor in which a polarizable electrode, a collecting electrode and a separator are stacked and impregnated with an electrolyte, at least the polarizable electrode and the collector are impregnated. Since the electrodes are sewn and integrated with sewing threads, mechanical pressure can be applied to the entire plane of the electrodes, and electrical conductivity between the electrodes can be improved. Furthermore, by stacking multiple layers including the separator, sewing them together with sewing threads, and integrating them, the multi-layered thin plate-shaped members can be overlapped as a unit, so that workability can be greatly improved. In addition, the "sewing hole group" formed during sewing is called "electrolyte passage".
Therefore, the workability can be further improved by shortening the electrolyte solution impregnating step.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of an electric double layer capacitor according to the present invention.

FIG. 2 is a diagram for explaining an example of sewing and integration of a multi-layer type electric double layer capacitor.

FIG. 3 is a diagram showing an example of housing a case of a sewn multilayer electric double layer capacitor.

FIG. 4 is a diagram for explaining a single-cell electric double-layer capacitor.

FIG. 5 is a diagram for explaining a pressing force applied to a single cell.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sewing thread, 2 ... Collector electrode, 3 ... Polarizable electrode, 4 ... Separator

Claims (2)

[Claims] 1. An electric double layer capacitor comprising a polarizable electrode, a collecting electrode, and a separator stacked and impregnated with an electrolytic solution, wherein at least the polarizable electrode and the collecting electrode are sewn and integrated with sewing threads. Electric double layer capacitor. 2. The electric double-layer capacitor according to claim 1, wherein a multi-layer capacitor including the separator is sewn with sewing threads and integrated.