JPH0447449B2 - - Google Patents

Abstract

PURPOSE:To obtain sufficient and uniform impregnated state of a sheetlike electrode with an electrolyte by damaging the surface smooth layer of the electrode on the surface of the electrode to form flaws for enhancing impregnating ability of the electrolyte. CONSTITUTION:A sheetlike electrode 12 is mounted through a conductive adhesive material 11 on the bottom of a metal case body 10, and flaws 13 for damaging the surface smooth layer of the electrode 12 are formed on the surface 12a of the electrode 12. Electrolyte poured from a nozzle 15 in the body 10 is sufficiently and uniformly impregnated in the electrode 12 from both the flaws 13 formed on the surface 12a of the electrode 12 and the side face 12b of a cut port in case of punching it from an electrode sheet 12S. Thus, an electric double layer capacitor having preferable life characteristic containing the electrode including good impregnation is obtained.

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a flat coin-shaped electric double layer capacitor, and more specifically, to its electrode. [Conventional example] An electric double layer capacitor includes a dish-shaped case body and a cap that is placed over the case body via a sealing means. During manufacturing, conductive adhesive is first applied to the bottoms of the case body and the cap. Sheet-like electrodes are attached to each via a material.
Next, an electrolytic solution is injected into the case body and the cap, and a separator is placed between each electrode. Thereafter, a cap is placed over the case body, and the periphery of the case body is caulked to create a coin cell of a predetermined capacity. [Problems to be solved by the invention] The characteristics of this type of electric double layer capacitor depend on the amount of electrolyte impregnated into the electrodes.
In the past, many products had poor impregnation properties and were found to be defective in product tests. The reason for this is explained with reference to Fig. 4.The electrode 1 is made by punching out a circular sheet from a sheet made by kneading, for example, activated carbon, carbon, and PTFE (polytetrafluoroethylene; binder) and rolling it to a predetermined thickness. Consisting of When this electrode 1 is microscopically observed, when it is rolled into a sheet, a dense smooth layer containing a particularly large amount of PTFE is formed on its surface. Therefore, even if the same electrode 1 is installed inside the case body 2 and the electrolyte is injected from the nozzle 3, the electrolyte will not reach the surface 1.
It is difficult to impregnate from A, and the electrode 1 is impregnated from the side surface 1b, which is the cut when punching the electrode, so in extreme cases, an unfilled portion X may be left behind. be. [Means for Solving the Problems] In order to solve the above-mentioned conventional drawbacks, in the present invention, each surface of the sheet-like electrodes facing each other with a separator in between is impregnated with an electrolytic solution by destroying the surface smooth layer. They are given scars to enhance their sex. [Function] According to the above configuration, the electrolytic solution impregnates not only the side surface of the electrode but also the scratched surface thereof, so that sufficient and uniform impregnation of the electrode with the electrolytic solution can be obtained. [Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 3. FIG. 1 illustrates a state in which a sheet-like electrode 12 is installed on the bottom of a metal case body 10 formed in a dish shape with a conductive adhesive 11 interposed therebetween.
The electrode 12 is made of a sheet prepared by kneading activated carbon, carbon, and PTFE and rolling it to a predetermined thickness, and then punched into a predetermined shape (for example, circular), as in the past.
There are scratches 1 on the surface 12a that destroy the surface smooth layer.
3 is provided. Here, the surface 12a to be scratched refers to the separator 1 of the sheet electrode 12.
7 (see FIG. 3). For example, as shown in FIG. 2, this scratch 13 is formed by pressing a mold 14 of an embossing machine having a large number of needle-like protrusions 14a onto the surface of an electrode sheet 12S, which is the base of the electrode 12. be done. In this embodiment, the electrode 12 has a diameter of 6 mm and a thickness of 0.5 mm, and its surface 12a has approximately 5 inverted conical needle insertion holes with a depth of 0.3 mm and an upper opening of 0.4 mm formed by the needle-like projections 14a. ~6 are provided. Therefore, as shown in FIG. 1, the electrolytic solution injected into the case body 10 from the nozzle 15 is punched out from the scratches 13 formed on the surface 12a of the sheet-shaped electrode 12 and the electrode sheet 12S. The same electrode 1 is removed from both side surfaces 12b, which are often cut.
2 will be sufficiently and uniformly impregnated. FIG. 3 shows the finally assembled electric double layer capacitor according to this embodiment. That is, the cap 20 is placed over the case body 10 shown in FIG. Electrode 1
2 is attached, and the same electrode 12 is also impregnated with an electrolytic solution in advance. When assembling, install the gasket 1 along the inner circumference of the case body 10.
6 is placed, and a separator 17 is placed inside the case body 10. Thereafter, the cap 20 is placed on the case body 10, and the opening edge of the case body 10 is caulked watertightly. The capacitance change and equivalent series resistance (ESR) of the thus obtained product according to the present invention and the conventional product were tested under high temperature load conditions of 70°C.
The changes are shown in the table below.

【table】

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to obtain an electric double layer capacitor having particularly good life characteristics and having a sheet-like electrode that is well impregnated with an electrolytic solution.

[Brief explanation of the drawing]

Figures 1 to 3 relate to embodiments of the present invention, with Figure 1 being a cross-sectional view for explaining the state in which the electrolyte is impregnated into a sheet-shaped electrode installed inside the case body, and Figure 2 3 is a cross-sectional view showing the state in which the electrode sheet, which is the base of the sheet-like electrode, is damaged; FIG. 3 is a cross-sectional view showing the finally assembled electric double layer capacitor according to the present invention; and FIG.
The figure is a sectional view similar to FIG. 1 for explaining a conventional example. In the figure, 10 is the case body, 11 is a conductive adhesive, 12 is a sheet electrode, 12a is its surface, 1
3 is a scratch, 14 is a mold, 14a is a needle-like projection, 15 is a nozzle, 16 is a gasket, 17 is a separator,
20 is a cap.

Claims (1)

[Claims] 1. A case body formed in a dish shape and a cap that is placed over the case body through a sealing means, and sheet-like electrodes are provided at the bottoms of the case body and the cap, respectively. In an electric double layer capacitor in which each electrode is impregnated with an electrolytic solution and a separator is interposed between them, each surface of the sheet-shaped electrode facing the separator has a smooth surface layer. An electric double layer capacitor characterized in that it is provided with scratches to destroy it and improve impregnation with the electrolyte. 2. The electric double layer capacitor according to claim 1, wherein the sheet-like electrode is made of a kneaded material of activated carbon, carbon, a predetermined binder, and the like. 3. The electric double layer capacitor according to claim 1, wherein the scratch is a needle insertion hole caused by embossing. 4. The electric double layer capacitor according to claim 1, wherein the scratch is a groove caused by a blade.