JPS6011637Y2 - Electrolytic capacitor - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a capacitor in which the exterior of an electrolytic capacitor element is improved.

Conventional electrolytic capacitors house a capacitor element impregnated with electrolyte in a metal case such as aluminum or a resin case such as epoxy resin or polypropylene resin, and then pass through the opening of the case with an external lead led out from the capacitor element. It was designed to be sealed using a sealing material such as rubber.

In conventional electrolytic capacitors with such an electrolyte, when a voltage is applied for a long time at high temperature, leakage current flows between the electrodes, accompanied by gas generation, and when there is no space between the capacitor element and the outer case. This leads to damage to the exterior material due to the increase in internal pressure and activation of the explosion-proof mechanism installed in the exterior case, resulting in a shortened lifespan.

For this reason, attempts have been made to create a space between the capacitor element and the outer case by using an outer case that is relatively larger than the capacitor element, or to develop an electrolytic solution that generates less gas.

However, capacitors such as electrolytic capacitors manufactured by these conventional manufacturing methods have the following drawbacks.

(1) The number of parts is large and the number of manufacturing steps increases, leading to an increase in cost.

(2) If a high-temperature, long-term life test is performed using a soft material such as rubber as a sealing material, the airtightness deteriorates and the electrical characteristics deteriorate.

(3) When cleaning the board after mounting it on a printed circuit board, there is a risk that cleaning liquid or the like will penetrate into the capacitor element and deteriorate its electrical characteristics.

Further, in order to prevent this, a process such as applying resin to the sealing part is required.

The present invention aims to eliminate these drawbacks and provide a highly reliable and inexpensive electrolytic capacitor without using an external case or parts for use in Japan.

Hereinafter, one embodiment of the present invention shown in FIGS. 1 and 2 will be described.

FIG. 1 is a sectional view of an electrolytic capacitor, and FIG. 2 is a cutaway perspective view of a main part of the same capacitor.A capacitor element 1 wound by a conventional method is impregnated with an electrolytic solution.

Reference numeral 2 denotes an external lead lead led out from the capacitor element 1.

Next, after adding a foaming agent, the capacitor element 1 is immersed in the heated and melted thermoplastic resin, and then hardened to form the capacitor element 1.
A foamed plastic layer 3 is formed on the outer surface of.

Further, the capacitor element 1 is coated with an ultraviolet curing resin, an epoxy resin, a urethane resin, etc. to form an exterior resin layer 4.

The electrolytic capacitor enclosed by the foamed plastic layer 3 in this way has an outer resin layer 4 and a capacitor element 1.
Since the porous plastic foam layer 3 is interposed between the
There is no practical problem with gas generation due to voltage application.

Further, since up to the 2 parts of the external lead leads are covered with the exterior resin layer 4 without using a mechanical sealing method, no deterioration of the electrical characteristics is observed even in a high temperature life test.

In the above-described embodiment, the foamed plastic layer 3 is formed on the bottom surface and the side peripheral surface of the capacitor element 1, but it may also be formed on the top surface of the capacitor element 1 or in the above-mentioned partial positions. has the same effect.

Further, another layer such as an insulating sleeve may be interposed between the foamed plastic resin layer 3 and the exterior resin layer 4.

Although the above-mentioned embodiments have been shown for electrolytic capacitors, similar effects can be obtained for capacitors that generate gas, such as plastic film capacitors and paper capacitors.

As described above, the electrolytic capacitor manufactured according to the present invention has far superior characteristics in terms of quality and characteristics compared to electrolytic capacitors that use conventional external cases, and has fewer parts and can be mass-produced, reducing production costs. The reduction effect is extremely high and has great industrial and practical value.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the electrolytic capacitor of the present invention.
FIG. 2 is a cutaway perspective view of essential parts of the capacitor. 1: capacitor element, 2: external lead, 3: foamed plastic layer, 4: exterior resin layer.

Claims (1)

[Scope of utility model registration request] An electrolytic capacitor is made by forming a foamed plastic layer on part or all of the outer surface of a wound capacitor element, and covering the entire surface with an exterior resin.