JPS6125244Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrolytic capacitor with an improved safety mechanism.

When a reverse voltage, continuous overvoltage, or abnormal pulse is applied to an electrolytic capacitor, an excessive current flows through the electrolyte, causing electrolysis and gas generation, and the equivalent resistance causes the electrolysis to occur due to the generation of Joule heat. The internal pressure of the capacitor increases and eventually explodes and breaks down. A similar phenomenon occurs when the elements of an electrolytic capacitor deteriorate for some reason. There are considerable differences depending on the structure and material of the sealing part of the electrolytic capacitor, but the diameter is 10
The internal pressure at which a mm-sized cylindrical case breaks is 30Kg/cm ²
Before and after. Therefore, it is quite dangerous if it explodes, so to avoid this danger, an explosion-proof mechanism is provided that allows the gas generated when a predetermined internal pressure is reached to escape to the outside of the case.

An example of a conventional explosion-proof mechanism for a relatively large electrolytic capacitor is shown in FIG. In the figure, 1 is a case made of aluminum or the like, 2 is a capacitor element, 3 is a drawer lead plate, 4 is a separator made of synthetic resin or the like with a through hole 4', and 5 is an elastic plate made of synthetic rubber or the like. , the separator plate 4 and the elastic plate 5 form a terminal plate. 6 is a terminal, and 7 is a rivet that fixedly connects the terminal 6 and the lead plate 3. The lead plate 3 led out from the capacitor element 2 impregnated with electrolyte is fixedly connected by crimping with rivets 7, and then the capacitor element 2 is housed in the case 1, and the terminal plate is inserted into the opening of the case 1. After fitting, the open end of the case 1 is sealed tightly. The explosion-proof mechanism in this case consists of a through hole 4' and a portion 5' of the elastic plate 5 disposed above the through hole 4'. When the internal pressure reaches a predetermined pressure, a portion 5' of the elastic plate 5 swells outward and ruptures, and the generated gas escapes to the outside through the through hole 4', thereby avoiding the risk of explosion. However, since this explosion-proof function is mostly dependent on the elastic plate 5,
Since it is necessary to select the thickness, hardness, type, etc. of the rubber so that it will break under the required internal pressure, it is actually relatively difficult to obtain a stable product with little variation. Furthermore, as rubber deteriorates over time, its hardness changes and cracks appear, making it extremely difficult to guarantee explosion-proof performance over many years.

In addition, as an explosion-proof mechanism other than the sealing part, a thick wall part and a thin wall part of various shapes are placed on the inner or outer surface of a capacitor case made of aluminum or the like, which expands due to an increase in internal pressure and causes the internal gas to escape. There is something that allows you to escape. In this case, although the explosion-proof mechanism of the sealing part can guarantee stability as described above, it has the disadvantage that it is vulnerable to mechanical shock from the outside and may break or become damaged during transportation.

In addition, all of the capacitors mentioned above operate the valve after a certain period of time has passed after an abnormality occurs inside the capacitor or in the external circuit, and wait for the internal pressure to rise due to gas, simply to prevent the capacitor from exploding. Since it is a mechanism for this purpose, it often causes failures in other circuit components before it breaks down. In addition, the electrolyte may scatter onto other printed circuit boards and circuit components due to the destruction, and sometimes elements may come out from the valve part, so from a circuit perspective,
The overall safety mechanism was not in place.

The present invention aims to eliminate the above-mentioned drawbacks, provide an inexpensive electrolytic capacitor that can reliably open the capacitor circuit in the event of an abnormality.

The present invention will be described below with reference to embodiments shown in FIGS. 2 to 4.

Figure 2 is a cross-sectional view of the main part of an electrolytic capacitor, and Figure 3 is a cross-sectional view of the main part of its seal, in which the external terminal 6 is pasted with a relatively thin piece of rubber that swells at a predetermined internal pressure using a rivet 12 made of aluminum or the like. A partition plate 10 provided with a through hole 9 through which a portion of the rivet 12 on the side opposite to the external terminal 6 passes is superimposed on the terminal plate 8. Next, the lead plate 3 led out from the capacitor element 2 is attached to the part of the rivet 12 protruding from the through hole 9 provided in the partition plate 10 through the washer 11 having a larger outer diameter than the through hole 9. The tip of the rivet 12 is connected by spot welding, etc., and this is housed in a case 1, and the partition plate 10 and terminal plate 8 are fitted into the opening of the case 1, and the product is completed by wrapping and sealing. . 13 is a connection part.

FIG. 4 shows a diagram of the operation of the safety device when an internal abnormality occurs and the internal pressure increases due to gas generation in the electrolytic capacitor of the present invention sealed as described above. That is, when the internal pressure inside the case 1 increases, the internal gas pushes up the relatively thin terminal plate 8 through the gas-passing through hole 14 provided in the partition plate 10 and the gap between the rivet through hole 9 and the rivet 2. The drawer lead plate 3 connected to the rivet 12 attached to the terminal plate 8 pushed up by the increase in internal pressure is inserted into the rivet through hole 9 of the partition plate 10.
Since it is supported by a washer 11 with a larger outer diameter, it is stuck to the rivet 12 and is not pushed upward, and when the internal pressure rises to a certain level, the drawer lead plate 3 is torn off from the rivet 12, and at the same time the capacitor becomes disconnected, and the progress of the defect stops. In addition, the terminal plate 8 and the partition plate 10 are both tightly sealed and a through hole 14 is provided in the center of the partition plate 10 to allow gas to pass through, so the terminal plate 8 can be designed to be thin, and the capacitor can be made thin. It is easy to bend even when the internal pressure is low, which can lead to early wire breakage.

In addition, the same effect can be obtained by using a rigid partition plate in which the washer 11 and the partition plate 10 are integrally formed.

As described above, the present invention disconnects the capacitor circuit due to a certain increase in internal pressure. Conventionally, electrolytic capacitors that would eventually explode and break due to the increase in internal pressure do not explode and are no longer triggered by an explosion. The various accidents that occurred could have been completely prevented.

As mentioned above, the electrolytic capacitor of the present invention is safe, simple in structure, and inexpensive, and has great industrial and practical value.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a conventional electrolytic capacitor, Figure 2 is a cross-sectional view of a conventional electrolytic capacitor.
The figure is a cross-sectional view of the main part of an embodiment of the electrolytic capacitor of the present invention, Figure 3 is a cross-sectional view of the main part of the sealed electrolytic capacitor of the present invention, and Figure 4 is the electrolytic capacitor of the present invention after the safety device is activated. It is a sectional view of the main part. 1...Capacitor case, 2...Capacitor element, 3...Output lead plate, 6...External terminal, 8...
...Terminal board, 9...Through hole, 10...Partition plate, 11
... Washer, 12 ... Rivet, 13 ... Connection part, 14 ... Through hole.

Claims (1)

[Scope of utility model registration request] A terminal plate 8 to which an external terminal 6 is mounted with a rivet 12 and expands under a predetermined internal pressure is superimposed on a partition plate 10 provided with a through hole 9 passing through the rivet 12 and a through hole 14 through which gas passes. The drawer lead plate 3 led out from the capacitor element 2 is connected to the rivet 12, and the drawer lead plate 3 is supported by a washer 11 having a larger outer diameter than the rivet through hole 9 of the partition plate 10, and the capacitor element 2
is housed in a case 1, and the overlapping partition plate 10 and terminal plate 8 are wrapped around the opening of the case 1 for sealing.