JPH0410522A - Aluminum electrolytic capacitor - Google Patents

Abstract

PURPOSE:To effectively absorb a driving electrolyte gushing out when an explosion-proof valve is actuated to avoid the running out of the electrolyte without hampering the operation capability of the valve by a method wherein an absorbing material having the absorbing property of the driving electrolyte and the air permeability is provided inside a metallic case so as to oppose to the explosion-proof valve CONSTITUTION:For example, an absorbing material 17 such as glass fiber, porus high molecule, etc., having the absorbing property of a driving electrolyte and the air permeability is provided on the inner surface of the ceiling part 11a of a metallic case 11 by bonding operation, etc., so as to oppose to an explosion-proof valve 16. When the explosion-proof valve 16 is immediately actuated in case of an emergency temperature rise or a boosted inner pressure inside the metallic case 11, the driving electrolyte going to gush out can be absorbed into the absorbing material 17 to avoid the running out of the electrolyte. Furthermore, the absorbing material 17 being provided inside the metallic case 11 falls down outside the metallic case 11 when the explosion-proof valve 16 is actuated.

Description

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

Conventional technology Conventional aluminum electrolytic capacitors are made by forming a dielectric oxide film on the surface of a roughened aluminum foil, and winding this together with a separator to form a capacitor element. It is constructed by enclosing it in a cylindrical aluminum case with a bottom. This aluminum electrolytic capacitor is made by covering the outer circumferential surface of the aluminum case with a vinyl chloride tube as an exterior material, and installing an explosion-proof valve made of a thin wall on the top plate of the aluminum case. A disc-shaped insulating plate is installed.

When the aluminum electrolytic capacitor is used at a higher temperature or higher voltage than its rated value, the temperature of the driving electrolyte rises and vaporizes, resulting in an increase in the internal pressure of the aluminum case. In this case, as mentioned above, the explosion-proof valve made of a thin wall is provided on the top plate of the aluminum case, so if the internal pressure of the aluminum case suddenly increases, the thin wall that makes up the explosion-proof valve will break and the valve will not move. Since the gas from the electrolyte will escape, a large explosion will not occur. When the explosion-proof valve operates, the gasified driving electrolyte is discharged from the explosion-proof valve portion to the outside. In this case, the gasified driving electrolyte is cooled by hitting the disc-shaped insulating plate provided on the explosion-proof valve, so that a portion of the gasified driving electrolyte liquefies and condenses on the back side of the insulating plate. The liquefied driving electrolyte then falls down the side of the aluminum case.
The aluminum electrolytic capacitor would fall onto the printed circuit board, causing a short circuit in the voltage application section and causing smoke and fire.

In order to solve these problems, an aluminum electrolytic capacitor having a structure as shown in FIG. 2 has been proposed, for example, as disclosed in Japanese Utility Model Application Publication No. 1-129819. That is, the aluminum electrolytic capacitor shown in FIG. 2 has an explosion-proof valve 2 provided on the top plate 1a of a bottomed cylindrical aluminum case 1, and an electrolyte absorbing material 3 having air permeability on the explosion-proof valve 2. It is fixed with an adhesive, and the electrolytic solution absorbing material 3 absorbs the driving electrolytic solution spouted from the explosion-proof valve 2 parts.

Problems to be Solved by the Invention However, in the conventional configuration described above, when the aluminum case 1 is deformed when the explosion-proof valve 2 is activated, the adhesive is stressed and destroyed, and as a result, the electrolyte absorbent 3 is damaged. There is a risk that the electrolyte absorbing material 3 may fall, and since the electrolyte absorbing material 3 is glued onto the explosion-proof valve 2, there is a problem in that it impedes the operability of the explosion-proof valve 2.

The present invention solves these problems by using aluminum that effectively absorbs the driving electrolyte that is spouted out when the explosion-proof valve is activated, without interfering with the operability of the explosion-proof valve, and prevents it from flowing outside. The purpose is to provide an electrolytic capacitor.

Means for Solving the Problems In order to achieve the above objects, the aluminum electrolytic capacitor of the present invention comprises: a capacitor element impregnated with a driving electrolyte; a bottomed cylindrical metal case in which the capacitor element is housed;
The metal case includes a sealing member that seals the opening of the metal case, and an explosion-proof valve provided on the top plate of the metal case, and a drive electrolyte is disposed within the metal case so as to face the explosion-proof valve. It is equipped with an absorbent material that has absorbent properties and breathability.

Effect According to the above configuration, an absorbent material having a property of absorbing the drive electrolyte and having breathability is placed inside the metal case and facing the explosion-proof valve provided on the top plate of the metal case. Therefore, the driving electrolyte that is spouted out when the explosion-proof valve is activated can be effectively absorbed by the absorbent material without interfering with the operation of the explosion-proof valve.As a result, the driving electrolyte does not flow out to the outside. Therefore, the voltage application section on the printed circuit board connected to this aluminum electrolytic capacitor will not be short-circuited. Furthermore, the problem that the absorbent material falls when the explosion-proof valve is activated can also be solved.

EXAMPLE Hereinafter, an example of the present invention will be described based on FIG. In FIG. 1, reference numeral 11 denotes a metal case made of aluminum and having a cylindrical shape with a bottom. This metal case 11 is equipped with a capacitor element 12 impregnated with a driving electrolyte, and this capacitor element 12 has a rough surface. It is constructed by forming a dielectric oxide film on the surface of aluminum foil and winding it together with a separator. Further, a pair of lead wires 13.13a are led out from the capacitor element 12, and a pair of external connection terminals 14.14a are connected to the pair of lead wires 13.13a by caulking at a portion of the sealing member 15 made of a terminal plate. It is connected. The sealing member 15 made of the terminal plate is disposed in the opening of the metal case 11,
The opening of the metal case 11 is sealed by curling the open end of the metal case 11.

Reference numeral 16 denotes an explosion-proof valve consisting of a thin wall portion provided on the top plate portion 11a of the metal case 11. The inner surface of the top plate portion 11a of the metal case 11, facing the explosion-proof valve 16, is provided with a driving electrolyte. An absorbent material 17 having absorbing properties and breathability, such as glass fiber, porous polymer, flame-retardant filter paper, or nonwoven fabric, is installed by adhesion or the like.

With the above configuration, if the temperature rises or the internal pressure of the metal case 11 rises during an abnormality, the explosion-proof valve 16 will operate quickly, and in this case, the drive electrolyte that is about to blow out will be activated. Since the liquid is absorbed by the absorbent material 17, it will not leak out to the outside.Also, since the absorbent material 17 is installed inside the metal case, it will fall outside the metal case when the explosion-proof valve 16 is activated. It's nothing.

Effects of the Invention As is clear from the description of the above embodiments, the aluminum electrolytic capacitor of the present invention is located inside a metal case, and has a driving electrolyte disposed opposite to an explosion-proof valve provided on the top plate of the metal case. Because the absorbent material has absorption properties and breathability, the driving electrolyte that is spouted out when the explosion-proof valve is activated can be effectively absorbed by the absorbent material without interfering with the operation of the explosion-proof valve. As a result, the driving electrolyte will not leak out to the outside, and therefore the voltage application section on the printed circuit board on which the aluminum electrolytic capacitor is set will not be short-circuited.

Furthermore, it is possible to solve the problem that the absorbent material falls when the explosion-proof valve is activated.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an aluminum electrolytic capacitor according to an embodiment of the present invention, and FIG. 2 is a perspective view of a conventional aluminum electrolytic capacitor. 11...Metal case, lla...Top plate part, 12...Capacitor element, 15...
・Sealing member, 16...Explosion-proof valve, 17...
・Absorbent material.

Claims (1)

[Claims] A capacitor element impregnated with a driving electrolyte, a bottomed cylindrical metal case housing the capacitor element, a sealing member sealing the opening of the metal case, and a sealing member provided on the top plate of the metal case. 1. An aluminum electrolytic capacitor comprising: an explosion-proof valve, and an absorbent material having a property of absorbing a driving electrolyte and having air permeability is disposed within the metal case so as to face the explosion-proof valve.