JPS5940522A - Electrolytic condenser - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrolytic capacitor, and an object of the present invention is to improve the performance of the capacitor by improving the sealing body.

Generally, as shown in Figures 1 and 2, electrolytic capacitors are made by forming a dielectric film on the surface of a metal foil with valve action such as aluminum or tantalum through anodizing treatment to form an anode body, which is opposed to the anode body. It is wound with a separator impregnated with a driving electrolyte (hereinafter referred to as electrolyte) between it and the cathode foil to form a capacitor element 1, and an internal lead 5 is drawn out from the capacitor element 1, and the internal lead 5 of the bracket is An external lead wire 4 is connected to the casing 2, which is housed in a metal case 2. In the case of FIG. 2, the internal lead 5 on the cathode side is connected to the case 2, and the opening of the case 2 is sealed with an elastic sealing member 3. In such an electrolytic capacitor, since an electrolytic solution is used, when the temperature becomes high, the electrolyte passes through the elastic sealing body 3 and dissipates to the outside.
When used in a high-temperature atmosphere for a long period of time, the electrolyte evaporates to dryness, causing the capacitor to no longer function as a capacitor or increasing the loss value of the capacitor.

For this reason, ethylene propylene rubber is often used as a sealing material with excellent heat resistance.
It can withstand long-term use at high temperatures of around 50°C and has relatively little change in hardness. However, gas permeability is on the same level as natural rubber, and airtightness cannot be maintained at high temperatures with respect to an electrolytic solution using an organic solvent such as dimethylformamide (hereinafter referred to as DMF), which is highly marketable.

In order to eliminate the above-mentioned drawbacks, the present invention uses a two-layer elastic body made of polyester elastomer and ethylene propylene rubber as the rubber material for the seal body.

The present invention will be explained below based on the embodiments shown in FIGS. 3 and 4.

Table 1 shows the nitrogen gas permeability, and Table 2 shows a comparison with the initial value of hardness measured after being left at 125°C for 1000 hours and then returning to room temperature.

Table 3 shows the changes in the rubber when immersed in DMF at 125°C for 500 hours.

Table 3 Based on the cholera test results, ethylene propylene rubber is DM
Although it is superior to electrolytes using F as a solvent, it has high gas permeability and lacks airtightness as an elastic sealant. Although polyester elastomer has good airtightness, it does not leak into areas where it comes into contact with an electrolyte containing DMF as a solvent.

Therefore, when using an electrolyte containing DMF,
Ethylene propylene rubber 6b is placed on the side in contact with the electrolyte, and a two-layer elastic sealing body made of polyester elastomer 6'' is placed on the outside to maintain airtightness, ensuring high reliability. A more reliable electrolytic capacitor can be obtained even when using a stable solvent such as ethylene glycol. Needless to say, it is possible.

Next, the rating is 10V, 220μF (10 Makotoφ x 20nmL)
and rated 50V, 10L1. F(8TnMφ×16+ra
20 in a 125'C atmosphere of a product using a two-layer elastic sealing body made of conventional ethylene propylene rubber, the polyester elastomer of the present invention, and ethylene propylene rubber as the elastic L1 body of the electrolytic capacitor L).
The life test results of 00 hours of rated voltage application are shown in Tables 3 and 5.
As shown in FIG.

The electrolyte used in this test was a solvent mixed with DMF. Moreover, the measured value shows the average value of 20 samples other than the sample. As is clear from the test results, the electrolytic capacitor using the two-layer elastic sealing body of the present invention has high performance and can guarantee high temperatures.
This is a high-performance, long-life, highly reliable capacitor.

The above-mentioned elastic sealing body is not limited to a two-layer structure, but can also be used as a multi-layer structure made by laminating silicone rubber or similar materials, or as a rubber material for bonding with a resin base material such as phenol. can get.

As described above, the present invention greatly contributes to improving the reliability of electrolytic capacitors and has extremely great industrial value.

[Brief explanation of drawings]

Figures 1 and 2 are cross-sectional views of conventional electrolytic capacitors, and Figure 3 is an embodiment of the present invention. FIG. 4 is a cross-sectional view of an electrolytic capacitor, FIG. 4 is a perspective view of an elastic sealing body of a capacitor according to the present invention, and FIGS. 5 and 6 are characteristic examples of electrolytic capacitors comparing a conventional product and a product of the present invention. stomach)
12 is a one-hour characteristic diagram of capacitance change rate, and (b) is a one-hour characteristic diagram of tan δ. 1: Capacitor element 2: Case 4: External ground wire
5: Internal parts - 1 and 6: Elastic body 6a: Polyester elastomer - 6b = ethylene propylene rubber Patent applicant Nippon Capacitor Industry Co., Ltd. Figure 1 Figure 3 Figure 2 Figure 4 Figure 5 (A) b) Tsuba Ch) Figure 6 (b) -(

Claims (1)

[Claims] An electrolytic capacitor characterized in that an elastic sealing body made of polyester elastomer with ethylene propylene rubber arranged on the surface facing the capacitor element is sealed to the opening of a case housing the capacitor element.