JPH0115177Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electrolytic capacitor with an improved explosion-proof structure in a relatively large capacity electrolytic capacitor using a sealing plate with screw terminals molded with resin.

Conventionally, the structure of these electrolytic capacitors is, for example, an aluminum case 1 as shown in Fig. 1.
Fix the capacitor element 3 with compound 2 inside.
The opening of the case 1 is sealed with a resin molded sealing plate 6 in which a screw terminal 4 is implanted and an explosion-proof valve 5 is provided at an arbitrary location, and the screw terminal 4 and the capacitor element 3 are connected to a lead wire 7. It is connected by . However, in the electrolytic capacitor configured in this way, if dielectric breakdown of the capacitor element 3 occurs near the top of the element 3, but if it occurs near the bottom of the capacitor element 3, the area near the bottom of the element 3 is a compound. 2, there is no place for the gas to escape, and the capacitor element 3 is pushed upwards, causing the capacitor element 3 to push up the sealing plate 6 and cause an explosion before the explosion-proof valve 5 provided on the resin-molded sealing plate 6 operates. It had a

The present invention was developed in view of the above points, and the purpose is to provide an extremely safe electrolytic capacitor by providing a gas vent plate on the end face of the capacitor element located at the bottom of the case. It is something.

An embodiment of the present invention will be described below with reference to the drawings. That is, as shown in FIG. 2, the capacitor element 13 is fixed in an aluminum case 11 with a compound 12 and stored in an upright position. At this time, as shown in FIGS. 3 to 5, the winding core hole 14 on the bottom surface of the element 13 has a bottomed protruding cylindrical portion 15 made of thermoplastic resin such as polyester or polypropylene, and has a bottom at its center. It consists of a radial groove part 16 provided around the protruding cylindrical part 15 so as to be connected to the bottomed protruding cylindrical part 15 without continuing to the outer peripheral end, and as shown in FIG. Made of resin and has a through hole 17 in the center and has a thickness of 3 to 6 μm.
The bottomed protruding cylindrical portion 15 of the gas venting disk 19 to which the circular thin film 18 is attached is fitted.
Then, the opening of the aluminum case 11 is sealed with a resin molded sealing plate 22 in which a screw terminal 20 is implanted and an explosion-proof valve 21 is provided at an arbitrary location, and the screw terminal 20 and the capacitor element 13 are connected with a lead wire 23. It is made by connecting.

In the electrolytic capacitor configured as described above, when gas is generated due to dielectric breakdown near the bottom of the capacitor element 13, since the gas venting disk 19 is disposed on the bottom of the capacitor element 13, the gas pressure is reduced to the level of the gas venting disk. The thin film 18 pasted on the plate 19 is broken and the particles pass through the radial grooves 16 and concentrate in the bottomed protruding cylindrical portion 15 . Since the bottomed protruding cylindrical portion 15 is fitted into the winding core hole 14 of the capacitor element 13, the gas pressure concentrated in the bottomed protruding cylindrical portion 15 passes through the winding core hole 14 to the upper part of the aluminum case 11 of the capacitor. Explosion-proof valve 2 installed on resin molded sealing plate 22
1 and is ejected to the outside, which can reliably prevent an explosion. In the above embodiment, the gas venting disk structure was explained by exemplifying a structure in which the bottomed protruding cylindrical part and the radial groove forming part were integrated in advance, but as shown in FIG. 7, a through hole 24 was provided in the center part. The eighth through hole 24 of the disk 26 is provided with a radial groove 25 that is connected to the through hole 24 and does not continue to the circular end.
As shown in the figure, a bottomed cylinder 28 having holes 27 corresponding to the number of radial grooves around the bottom is fitted,
The radial groove part 25 has a combined structure in which the holes 27 are made to coincide with each other, and as shown in FIG. Good too. In addition, in each of the above embodiments, a circular thin film was used as an example of the thin film to be attached to the radial groove surface, and a case where the thin film was attached to the entire surface was explained. can.

As described above, according to the present invention, in an electrolytic capacitor in which a capacitor element is housed at the bottom of the case via a compound and the case opening is sealed with a resin-molded sealing plate, the capacitor element is located at the bottom of the case at the end face of the capacitor element. Dielectric breakdown at the bottom of the capacitor element can be prevented by fitting and arranging the bottomed protruding cylindrical part of the gas venting disk, which is composed of a radial groove part provided in connection with the bottomed protruding cylindrical part in the winding core hole of the surface. It is possible to obtain an extremely safe electrolytic capacitor that can reliably perform the function of an explosion-proof valve even if an explosion occurs.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an electrolytic capacitor according to a conventional example, Fig. 2 is a sectional view showing an electrolytic capacitor according to an embodiment of the present invention, and Figs. 3 to 6 are sectional views showing an electrolytic capacitor shown in Fig. 2. Regarding the constituent parts, Fig. 3 is a perspective view showing a gas venting disk, Fig. 4 is a plan view showing a state in which a thin film is attached to the gas venting disk, and Fig. 5 is a perspective view showing a gas venting disk.
The figures are a sectional view taken along the line A-A in FIG. 4, FIG. 6 is a perspective view showing a thin film, FIGS. 7 to 9 relate to other embodiments of the present invention, and FIG. FIG. 8 is a perspective view showing a cylinder with a bottom, and FIG. 9 is a sectional view showing a gas venting disk obtained by combining the parts shown in FIGS. 7 and 8 and pasting a thin film thereon. 11... Aluminum case, 12... Compound, 13... Capacitor element, 14... Winding core hole, 15... Bottomed protruding cylindrical portion, 16, 25... Radial groove, 18, 29... Thin film, 19, 30...
Gas venting disc, 21... explosion-proof valve, 22... resin molded sealing plate.

Claims (1)

[Scope of utility model registration request] An aluminum case, a compound injected into the inner bottom of the case, a capacitor element partially embedded and fixed in the compound, and a center part with a bottom protruding from the center part disposed closely to the bottom of the element embedded in the compound. A cylindrical part, a radial groove provided around the cylindrical part, connected to the cylindrical part without continuing to the outer circumferential end, a gas venting disk made of a thin film attached to the groove surface, and the metal case opening. 1. An electrolytic capacitor, comprising: a resin-molded sealing plate provided with a sealed explosion-proof valve, and the bottomed protruding cylindrical portion is fitted into the capacitor element winding core hole.