JPH03175607A - Electric double-layer capacitor - Google Patents

Abstract

PURPOSE:To decrease the contact resistance between a conductive separator and an outer package case and to obtain a small equivalent series resistance even if the pressure at the time of caulking and sealing of a port by providing the outer package case whose bottom surface in contact with the surface of the conductor separator is machined in an irregular shape. CONSTITUTION:An electric double-layer capacitor element 5a is constituted of the following parts: an iron transmitting and non-electron-conducting porous separator 11, a pair of paste electrode layers 10 which are separated through the porous separator 11, ion impermeable and electron conducting conductive separators 8 which are arranged through the paste electrode layers 10 and nonconducting gaskets 9 which are provided at the peripheral part of the above described pair of the paste electrode layers 10 between the conductive separators 8. A laminated body 5 of the electric double-layer capacitor elements 5a is contained in an outer package case 4. Thus an electric double-layer capacitor is obtained. In this capacitor, the bottom surface of the outer package case 4 which is in contact with the surface of the conductive separator 8 is machined in an irregular shape. For example, the outer package case 4 wherein protruding parts having the height of 0.2mm and the width of 0.5mm are machined in the concentric circles having the diameters of 2mm, 3.5mm and 5mm is used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electric double layer capacitor, and particularly to an electric double layer capacitor with reduced contact resistance.

[Conventional technology]

In general, an electric double layer capacitor element (hereinafter referred to as a basic cell) using carbon paste electrodes consists of a pair of cells separated by a porous separator 11 that is ion permeable and non-electron conductive, as shown in FIG. An ion-impermeable conductive separator 8 disposed through a carbon paste electrode 10 made of powdered activated carbon and an electrolyte solution, and carbon interposed between the conductive separator 8 in the periphery of the pair of carbon paste electrodes 10. It has a structure including a non-conductive gasket 9 provided to hold the paste electrode 10 and isolate it from the outside world.

Furthermore, as shown in FIG. 6, the electric double layer capacitor is constructed by short-circuiting the laminate 5, which is formed by laminating the necessary number of basic cells 5a according to the working voltage, between the metal exterior case 12 and the side surface of the laminate 5 of the basic cells. It has a structure in which the first and second electrode plates 1.2 are used as electrodes. In the electric double layer capacitor, in order to reduce the contact resistance within the carbon paste electrode 10, the button between the basic cells 53, and between the exterior case 12 and the basic cell 5a, the laminate 5 of the basic cell 5a is coated with 1 to 1004/car from above and below. While applying pressure and holding the pressure, the open end of the outer case 12 is bent inward and sealed by caulking.

[Problem to be solved by the invention]

The conventional electric double layer capacitor described above uses pressure sealing via the electrode plate and the insulating case in order to reduce the contact resistance between the activated carbon, the button between the conductive separators, and the contact resistance between the conductive separator and the exterior case. ing. In this case, if excessive pressure (more than 1004/cJ) is applied to lower the equivalent series resistance (hereinafter referred to as ESR) of the electric double layer capacitor, excessive pressure will be applied to the basic cell, and the porous separator that is the constituent material, Unbalanced pressure and voltage are applied to the conductive separator,
There is a drawback that problems such as tearing and distortion occur, resulting in poor characteristics.

An object of the present invention is to provide an electric double layer capacitor that can reduce the contact resistance between a conductive separator and an exterior case and obtain a small EAR even if the pressure at the time of caulking and sealing is low.

[Means to solve the problem]

The electric double layer content of the present invention includes an ion-permeable and non-electronically conductive porous separator, a pair of paste electrode layers separated through the porous separator, and a pair of paste electrode layers arranged through the paste electrode layer. An electric double layer capacitor element comprising an ion-impermeable, electronically conductive conductive separator, and a non-conductive gasket interposed between the aforementioned conductive separators in the periphery of the aforementioned pair of paste electrode layers. The electric double layer capacitor obtained by housing the laminate of 3 in an exterior case has an exterior case whose bottom surface, which is in contact with the surface of the conductive separator described above, is textured.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, and FIG. 2(a)
(b) is a top view and a vertical cross-sectional view of the exterior case according to the present invention.

! First, after stacking six basic cells 5a to form the laminate 5, three metal plates 4a are placed on the outer case cutting die 7 as shown in FIG. Apply pressure,
Height 0.2 tx, width 0 as shown in Figure 2 (a) and (b)
The convex part of ゜51oE has a radius of 2131.3-5mm, 5m
The laminate 5 is housed in an exterior case 4 according to the present invention that has been processed to have concentric circles, and a 301fe/ci machine is attached to the laminate 5 via the first and second electrode plates 1.2 and the insulating case 3. The upper end of the grooved outer case was held in this state by applying a certain pressure, and the upper end was caulked to obtain an electric double layer container with an operating voltage of 5 . Further, a conventional electric double layer capacitor was obtained under the same manufacturing conditions as the present invention except that the outer case was changed to a conventional one.

Table 1 shows the average values of the electrical characteristics of 650 electric double layer capacitors of the present invention and the conventional example.

Table: The present invention has an equivalent series resistance of about 20% compared to the conventional example.
% could be reduced.

FIGS. 3(a) and (bJ are a top view button and a vertical cross-sectional view of another embodiment of the exterior case according to the present invention. FIGS. 3(a!,
The exterior case of the present invention shown in (b) has a height of 0.21K.
, a hemispherical convex portion with a radius of 0.511 is processed in the same manner as in the first embodiment. An electric double layer capacitor of the present invention was obtained under the same manufacturing conditions as in the first example except that the outer case of the present invention was used.

Further, a conventional electric double layer capacitor was obtained under the same manufacturing conditions as the present invention except that the outer case was changed to a conventional one.

Table 2 shows the average values of the electrical characteristics of 650 electric double layer capacitors of the present invention and the conventional example. The present invention was able to reduce the equivalent series resistance by about 15% compared to the conventional example.

In addition to the first and second embodiments, the effects of the present invention can be obtained regardless of the shape of the unevenness on the bottom surface of the outer case, as long as the unevenness widens the contact area between the conductive separator and the outer case. It is not even possible to say that it will be done.

〔Effect of the invention〕

As explained above, the present invention reduces the contact resistance between the conductive separator and the exterior case by processing the bottom surface of the exterior case in contact with the surface of the conductive separator into an uneven shape, thereby lowering the pressure against the date and time of caulking. It is also possible to obtain a small ESR.

As described above, the electric double layer capacitor of the present invention has great industrial value.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an electric double layer capacitor according to an embodiment of the present invention, and FIGS. 2(a) and 2(b) are top views and The vertical cross-sectional view, FIGS.
C) is a simplified diagram of the procedure for processing the outer case according to the present invention;
FIG. 5 is a longitudinal sectional view of a basic cell of an electric double layer capacitor, and FIG. 6 is a longitudinal sectional view of an example of a conventional electric double layer capacitor. 1... First electrode plate, 2... Second electrode plate, 3...
・Insulation case, 4a...Metal plate before exterior case processing,
4... Metal exterior case according to the present invention, 5a... Basic cell, 5... Laminated body, 6... Pressurizing bar,
7... Exterior case cutting die, 8... Conductive separator, 9... Non-conductive gasket, 10... Carbon paste electrode, 11... Porous separator, 12...
Traditional metal exterior case.

Claims (1)

[Claims] an ion-permeable and non-electronically conductive porous separator; a pair of paste electrode layers separated through the porous separator; and an ion-impermeable and electronically conductive porous separator disposed through the paste electrode layer. Obtained by housing a laminate of an electric double layer capacitor element, which is composed of a conductive separator and a non-conductive gasket interposed between the conductive separators around the pair of paste electrode layers, in an exterior case. An electric double layer capacitor characterized in that the electric double layer capacitor has an exterior case whose bottom surface in contact with the surface of the conductive separator is processed into an uneven shape.