JPH0491421A - Aluminum electrolytic capacitor - Google Patents

Abstract

PURPOSE:To obtain a capacitor which can prevent a gas of an organic solvent constituting an electrolyte for drive use from flowing out to the outside by a method wherein a porous sheet is arranged, via a space part, in the upper part of an explosion-proof valve installed in the ceiling part of a metal case and a separation film through which the organic solvent cannot be permeated but hydrogen gas can be permeated is arranged on the outside of the porous sheet. CONSTITUTION:The following are provided: a capacitor element 1 which has been impregnated with an electrolyte for drive use; a bottomed cylindrical metal case 2 in which the capacitor element 1 is built; one pair of lead wires 3, 3a which have been extracted from the capacitor element 1; and one pair of terminals 4, 4a, for external connection use, which have been connected to the pair of lead wires 3, 3a. A porous sheet 7 is arranged, via a space part 10, in the upper part of an explosion- proof valve 6 installed in the ceiling part of the metal case 2. A separation film 8 through which an organic solvent such as ethylene glycol or the like cannot be permeated is arranged on the outside of the porous sheet 7. For example, a separate porous sheet 7a is arranged additionally on said separation film 8, and the porous sheets 7, 7a and the separation film 8 are held and fixed by using a jig 9 for fixation use.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an aluminum electrolytic capacitor.

Conventional technology In conventional aluminum electrolytic capacitors, a dielectric oxide film is formed on the surface of an anode foil made of roughened aluminum foil, and the anode foil and cathode foil are wound together with a separator to form a capacitor element. It was constructed by impregnating the capacitor element with a driving electrolyte and enclosing the capacitor element in a metal case made of aluminum.

When an overvoltage higher than the rated voltage is applied to this aluminum electrolytic capacitor, the organic solvent that makes up the drive electrolyte impregnated in the capacitor element vaporizes due to the temperature rise, and hydrogen gas is generated through an electrochemical reaction. As a result, the internal pressure of the metal case increases. In this case, if the internal pressure of the metal case exceeds the sealing force of the metal case's sealing member, the capacitor element may come off from the metal case and fly out of the metal case, or the metal case may jump, which is extremely dangerous. It is something.

Therefore, in this type of aluminum electrolytic capacitor, a weak point consisting of a thin wall is usually provided in the top plate of the metal case, and when the internal pressure of this metal case rises abnormally, the weak point breaks and the metal Since the organic solvent gas constituting the driving electrolyte inside the case flows out, a major explosion will not occur.

Problems to be Solved by the Invention However, in the above-mentioned conventional aluminum electrolytic capacitor, the organic solvent gas that makes up the driving electrolyte leaks out of the capacitor, so the inside of the equipment in which this aluminum electrolytic capacitor is set is leaked. The problem was that the smoke became dirty and could not be distinguished from smoke caused by flames.

The present invention is intended to solve these problems, and an object of the present invention is to provide an aluminum electrolytic capacitor that can prevent the organic solvent gas constituting the driving electrolyte from leaking to the outside. It is something.

Means for Solving the Problems In order to achieve the above object, the aluminum electrolytic capacitor of the present invention includes a capacitor element impregnated with a driving electrolyte, a bottomed cylindrical metal case containing the capacitor element,
a pair of lead wires derived from the capacitor element;
It includes a pair of external connection terminals connected to the pair of lead wires and a sealing member that seals the opening of the metal case, and defines a space above the explosion-proof valve provided on the top plate of the metal case. A perforated plate is installed through the porous plate, and a separation membrane that does not allow organic solvents such as ethylene glycol to permeate but allows hydrogen gas to permeate is placed on the outside of the perforated plate.

Function According to the aluminum electrolytic capacitor having the above structure, a perforated plate is installed through a space above the explosion-proof valve provided on the top plate of the metal case, and an organic solvent such as ethylene glycol is placed on the outside of this perforated plate. Because a separation membrane is installed that does not allow hydrogen gas to pass through, but allows hydrogen gas to pass through, abnormal stress such as overvoltage is applied to the aluminum electrolytic capacitor, causing the explosion-proof valve to operate.
Even if the organic solvent gas and hydrogen gas that make up the drive electrolyte blow out from this explosion-proof valve, the separation membrane installed above the explosion-proof valve will not allow the organic solvent to pass through, but will allow hydrogen gas to pass through. Due to the presence of , the organic solvent gas hits the separation membrane and is cooled, liquefies, and falls onto the top plate of the metal case. On the other hand, hydrogen gas is released to the outside, so it The internal pressure is reduced, which eliminates the danger of explosion and also prevents the organic solvent gas constituting the driving electrolyte from leaking to the outside.

EXAMPLE Hereinafter, an example of the present invention will be described based on the accompanying drawings. In FIG. 1, 1 is a capacitor element, and this capacitor element 1 is made by forming a dielectric oxide film on the surface of an anode foil made of roughened aluminum foil, and winding this anode foil and cathode foil together with a separator. It is composed of: The capacitor element 1 is impregnated with a driving electrolyte, and the capacitor element 1 is installed in a bottomed cylindrical metal case 2 made of aluminum.

Further, a pair of lead wires 3, 3 are connected from the capacitor element 1.
A is led out, and a pair of external connection terminals 4, 4a are connected to the pair of lead wires 3, 3a by caulking at a portion of a sealing member 5 made of a terminal plate. The sealing member 5 made of the terminal plate is disposed in the opening of the metal case 2,
By sealing the open end of the metal case 2, the opening of the metal case 2 is sealed. Further, an explosion-proof valve 6 made of a thin weak point is formed on the top plate portion 2a of the metal case 2.

Further, a perforated plate 7 is installed above the explosion-proof valve with a space 10 in between, and on this perforated plate 7, an organic solvent such as ethylene glycol does not permeate, but hydrogen gas does not permeate. A separation membrane 8 to be obtained is placed, and a separate perforated plate 7a is placed above this separation membrane 8. The perforated plate 7.7a and the separation membrane 8 are held and fixed by a fixing jig 9, and the fixing jig 9 is fixed to the top plate 2a side of the metal case 2.

The operation in the above configuration will be explained. When an abnormal voltage or the like is applied to this aluminum electrolytic capacitor, the internal pressure of the metal case 2 rises, and the explosion-proof valve 6 provided on the top plate 2a of the metal case 2 is activated, causing the drive impregnated in the capacitor element l to Even if the organic solvent gas and hydrogen gas constituting the electrolyte are ejected from the explosion-proof valve 6, the organic solvent gas hits the separation membrane 8 and is cooled, liquefies and flows onto the top plate 2a of the metal case 2. On the other hand, the hydrogen gas passes through the separation membrane 8 and is released to the outside, so the internal pressure of the metal case 2 decreases, eliminating the risk of explosion, and the organic solvent gas is removed from the aluminum electrolyte. It is also possible to prevent leakage to the outside of the capacitor.

Effects of the Invention As is clear from the description of the embodiments above, the aluminum electrolytic capacitor of the present invention has a perforated plate installed above the explosion-proof valve provided on the top plate of the metal case through a space, and Because a separation membrane is placed on the outside of the plate that does not allow organic solvents such as ethylene glycol to pass through, but allows hydrogen gas to pass through, the explosion-proof valve may operate if abnormal stress such as overvoltage is applied to the aluminum electrolytic capacitor. Even if the organic solvent gas and hydrogen gas that make up the drive electrolyte blow out from this explosion-proof valve, the organic solvent installed above the explosion-proof valve will not pass through, but the separation will allow hydrogen gas to pass through. Due to the presence of the membrane, the ia solvent gas once hits the separation membrane and is cooled, liquefies, and falls onto the top plate of the metal case, and the hydrogen gas is released to the outside, so the metal case The internal pressure of the battery is reduced, which eliminates the risk of explosion, and also prevents the organic solvent gas constituting the driving electrolyte from leaking to the outside.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an aluminum electrolytic capacitor showing one embodiment of the present invention. 1...Capacitor element, 2...Metal case, 3゜3a...Pair of lead wires, 4.4a
......Pair of external connection terminals, 5...Sealing member, 6...Explosion proof valve, 7...Perforated plate, 8... Separation membrane, 10...Space part.

Claims (1)

[Claims] A capacitor element impregnated with a driving electrolyte, a bottomed cylindrical metal case containing the capacitor element, a pair of lead wires led out from the capacitor element, and a pair connected to the pair of lead wires. and a sealing member for sealing the opening of the metal case, a perforated plate is installed through a space above an explosion-proof valve provided on the ceiling of the metal case, and An aluminum electrolytic capacitor characterized by disposing a separation membrane on the outside of the plate that does not allow organic solvents such as ethylene glycol to pass through, but allows hydrogen gas to pass through.