JPH0533001Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an electrolytic capacitor equipped with a safety valve.

BACKGROUND TECHNOLOGY In general, aluminum electrolytic capacitors are manufactured by enlarging the surface area of aluminum foil by etching, and then forming an electrode foil on which an oxide film is formed by chemical conversion and facing each other with electrolytic paper interposed therebetween to form a wound capacitor element.

Next, the capacitor element is impregnated with a driving electrolytic solution consisting of ethylene glycol, water, an organic acid such as adipic acid or boric acid, or a salt thereof, and the capacitor element is housed in a case and sealed.

In electrolytic capacitors manufactured in this way, when used below the normal withstand voltage, the anode foil has some defects in the film, so current flows through the defects, but the driving electrolyte described above It also has the ability to repair defects in the film, and generates a small amount of hydrogen gas at the same time as repairing.

These currents are temperature-dependent and flow well at high temperatures, resulting in the generation of a lot of gas. Therefore, the pressure inside the capacitor increases with long-term use. Furthermore, in an area where the withstand voltage is exceeded or where a voltage is applied in the opposite direction, a significantly large current flows to form a new film, and a large amount of gas is generated, causing the internal pressure to rise rapidly. If this internal pressure continues to rise, there is a danger that it will eventually lead to an explosion, so generally a thin section is provided in the case or sealing section in advance, and when the internal pressure exceeds a certain level, the thin section is ruptured to quickly release the internal pressure. A structure called an explosion-proof valve was adopted.

Problems that the invention aims to solve In these explosion-proof valve structures, once the explosion-proof valve is activated, it cannot return to its original state and maintain a sealed state, causing the driving electrolyte in the element to volatilize and dry up. , the capacitor loses its function due to capacitance loss and large losses.

As mentioned above, increases in internal pressure occur due to long-term use, under some abnormal conditions, or due to the weight of aluminum electrolytic capacitors, but in recent years there has been a strong desire for aluminum electrolytic capacitors to have longer lifespans and be more compact. The development of electrode foils and electrolytes that generate less generation is progressing, but efforts are being made to ensure that they have sufficient structural strength to withstand internal pressure and that valves operate at relatively high pressures.

However, when the operating pressure of an explosion-proof valve is increased, the internal pressure naturally increases, causing smoke and bursting sounds during operation, secondary disasters due to the contents flying out, and operability in the event of a sudden increase in pressure. There were problems such as deterioration.

Means for Solving the Problems The present invention solves the above-mentioned problems, and provides an electrolytic capacitor in which a capacitor element is housed in a case, and a sealing plate is fitted into the opening of the case to seal it. An electrolytic device characterized in that it is equipped with a returnable safety valve consisting of a through hole provided in a plate, a spherical, conical, or elliptical safety valve that contacts so as to close the outer surface of the through hole, and a cap that presses the safety valve. It is a capacitor.

Function When the gas generated from the capacitor element reaches a predetermined pressure, it pushes up the safety valve through the through hole provided in the sealing plate and escapes to the outside. Then, when the internal pressure decreases, the cap is in pressure contact with the safety valve, so the spherical, conical, or elliptical safety valve returns to its original position and closes the outer surface of the through hole and is sealed. Therefore, only unnecessary gas is discharged, and the capacitor function can be maintained even after that.

Embodiments The present invention will be explained below with reference to embodiments shown in FIGS. 1 to 4. Figure 2 shows a sealing plate 1 made of a rubber-covered Bakelite plate, with rivet holes 2 for fixing terminals, through holes 3 for safety valves, and rivet holes 4 for fixing caps arranged around the through holes 3 at an angle of 120 degrees to each other. There are three locations in total.

Using the sealing plate 1, as shown in FIG. 1, a safety valve 5 made of a spherical elastic body made of rubber, plastic, etc. is brought into contact with the outer surface of the through hole 3 so as to close it, and a cap 6 is placed on top of the safety valve 5. The cap 6 is fixed to the sealing plate 1 using the rivets 7.
The safety valve 5 is pressed against the pressure. Note that a hole 6a is provided in the cap 6 to facilitate the release of gas. Then, a rivet 8 is inserted into the rivet hole 2, and the terminal 9 is crimped and fixed to the sealing plate 1. Then, the rivet 8 is connected to a tab 10 for drawing out an electrode led out from the capacitor element 9 and housed in a case 11, and a sealing plate 1 is fitted into the opening of the case 11 and sealed by tightening. Then, electricity is applied between the terminals 9 and 9 to perform aging treatment and the product is completed. The electrolytic capacitor of the present invention has capacitor element 1 as described above.
When the gas generated from the
As shown by the arrow in the figure, the safety valve 5 is pushed up through the through hole 3 provided in the sealing plate 1 and escapes outward. When the internal pressure drops, the cap 6 presses against the safety valve, so the safety valve returns to its original position and is sealed. .

FIG. 4 shows another embodiment in which a spherical ceramic is used as the safety valve 12 and a spring 13 is connected between the safety valve 12 and the cap 14.
This is an intervening method.

In the above embodiments, the shape of the safety valve has been described as being spherical, but any shape that closes the outer surface of the through hole 3 may be used, such as a conical shape or an elliptical spherical shape. The cap does not necessarily need to be fixed in three places, but may be fixed in one place.

Effects of the Invention Since the present invention is constructed as described above, the explosion-proof valve does not expand or open during the aging process, and defects in the film can be repaired. It has the effect of extending lifespan, and has great practical value.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of essential parts of an embodiment of the electrolytic capacitor of the present invention, Fig. 2 is a plan view of an embodiment of the sealing plate of the electrolytic capacitor of the present invention, and Fig. 3 is a sectional view of an embodiment of the electrolytic capacitor of the present invention. FIG. 4, which is an explanatory view of the operating state of the safety valve, is a sectional view of the main part of another embodiment of the electrolytic capacitor of the present invention. 1... Sealing plate, 3... Through hole, 5, 12... Safety valve, 6, 14... Cap.

Claims (1)

[Scope of utility model claims] In an electrolytic capacitor in which a capacitor element is housed in a case and a sealing plate is fitted to the opening of the case to seal it, a spherical capacitor is in contact with a through hole provided in the sealing plate so as to close the outer surface of the through hole. Alternatively, an electrolytic capacitor comprising a returnable safety valve comprising a conical or elliptical safety valve and a cap that presses the safety valve.