JPH03179721A - Aluminum electrolytic capacitor - Google Patents

Abstract

PURPOSE:To prevent driving electrolyte gas from escaping outside by a method wherein a varistor, having the threshold voltage almost equal to the surface voltage of an electrolytic capacitor, is connected between a pair of electrode terminals. CONSTITUTION:Between a pair of electrode terminals 2 and 2a provided on the main body 1 of an aluminum electrolytic capacitor, a safety device 3, consisting of a fuse or a breaker and the like, is connected to the electrode terminal 2. The varistor 4, which is connected between a pair of electrode terminals 2 and 2a, is an element made of ceramic, and has a property that it function as an insulator while the voltage applied is lower than a specific one, but it becomes a conductor while the voltage exceeds the specific voltage.

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 was constructed by enclosing it in an aluminum case.

When this aluminum electrolytic capacitor is used at a higher temperature or higher voltage than the rated value, the temperature of the driving electrolyte contained in the capacitor element rises and vaporizes.
The internal pressure of the aluminum case increases. In this case, if the internal pressure of the aluminum case exceeds the sealing force of the sealing member of the aluminum case, the capacitor element will come off the aluminum case and fly out of the aluminum case, or the aluminum case will fly off, which is extremely dangerous. It is what it is.

Therefore, this type of aluminum electrolytic capacitor usually has a weak point in the sealing member or the aluminum case, and when the internal pressure of the aluminum case suddenly increases, the weak point breaks and the driving electrolyte in the aluminum case leaks. Since the gas escapes to the outside, it does not result in a large explosion.

Problems to be Solved by the Invention However, in the above-mentioned conventional aluminum electrolytic capacitors, gas from the driving electrolyte exits outside the capacitor, which may stain the inside of the equipment in which the aluminum electrolytic capacitors are installed or cause fire hazards. The problem was that it was indistinguishable from smoke.

The present invention solves these problems and aims to provide an aluminum electrolytic capacitor that can prevent the gas of the driving electrolyte from flowing out.

Means for Solving the Problems In order to achieve the above objects, the aluminum electrolytic capacitor of the present invention includes an aluminum electrolytic capacitor body having a pair of electrode terminals, and a capacitor connected to one of the pair of electrode terminals. and a safety device, between the pair of electrode terminals,
A varistor whose threshold voltage is approximately equal to the surge voltage of an aluminum electrolytic capacitor is connected.

Function According to the above configuration, a varistor whose threshold voltage is approximately equal to the surge voltage of the aluminum electrolytic capacitor is connected between a pair of electrode terminals provided on the aluminum electrolytic capacitor body, and this varistor is a ceramic element. When the applied voltage is below a certain voltage, the aluminum electrolytic capacitor is an insulator, but when the voltage exceeds a certain level, the resistance value drops rapidly and it becomes a conductor. Therefore, if an abnormal voltage is applied to the aluminum electrolytic capacitor body, The resistance value of the varistor decreases and the varistor becomes a conductor, which causes a large current to flow through the varistor to the safety device connected to one electrode terminal, operating the safety device, for example, blowing a fuse and interrupting the electrical circuit. be able to.

In this case, the operation is instantaneous; for example, the electric circuit is cut off before a safety device such as an explosion-proof valve installed in the metal case is activated, so the gas from the driving electrolyte is transferred to the aluminum electrolytic capacitor. can be prevented from leaking to the outside.

Embodiment Hereinafter, one embodiment of the present invention will be described based on the accompanying drawings. In the figure, 1 is an aluminum electrolytic capacitor body, and this aluminum electrolytic capacitor body 1 has a capacitor element formed by forming a dielectric oxide film on the surface of a roughened aluminum foil and winding this together with a separator. However, this capacitor element is sealed together with a driving electrolyte in an aluminum case. Reference numerals 2 and 2a denote a pair of electrode terminals provided on the aluminum electrolytic capacitor body 1. Of the pair of electrode terminals 2 and 2a, one electrode terminal 2 is connected to a safety device 3 such as a fuse or a breaker. . 4 is a varistor connected between the pair of electrode terminals 2 and 28; this varistor 4 is a ceramic element, and is an insulator when the applied voltage is below a certain voltage; When this happens, the resistance value decreases rapidly and the material has the property of becoming a conductor.

20, which is then used for the switching power supply input circuit.
An aluminum electrolytic capacitor of 0wv330μF is prepared as a sample, and the threshold voltage is approximately equal to the surge voltage (250V) of the aluminum electrolytic capacitor, and the current capacity is When a 20A zinc oxide type varistor 4 was connected and an abnormal voltage of 360V was applied between the pair of electrode terminals 2.2a, a current of 10 to 15A flowed through the varistor 4 at the same time as this application was applied, and the current flowed for about 1 second. The fuse or breaker that constitutes the safety device 3 was blown, and the electric circuit was cut off. In this case, the safety device 3 consisting of a fuse or breaker operates instantly to cut off the electric circuit before the explosion-proof valve installed in the aluminum case operates, so that the gas from the drive electrolyte leaks outside the aluminum electrolytic capacitor. There will be no leakage.

Effects of the Invention As is clear from the description of the above embodiments, the aluminum electrolytic capacitor of the present invention has a safety device connected to one of the pair of electrode terminals provided on the aluminum electrolytic capacitor body, and Since a varistor whose threshold voltage is approximately equal to the surge voltage of the aluminum electrolytic capacitor is connected between the electrode terminals of the The safety device can be operated via the varistor to interrupt the electric circuit before the varistor is activated, and as a result, it is possible to prevent the drive electrolyte gas from leaking to the outside of the aluminum electrolytic capacitor. It is possible.

[Brief explanation of drawings]

FIG. 1 is an electrical circuit diagram showing an aluminum electrolytic capacitor according to an embodiment of the present invention in which a safety device and a varistor are connected. 1... Aluminum electrolytic capacitor body, 2, 2a.
...Pair of electrode terminals, 3...Safety device,
4...Barista.

Claims (1)

[Claims] It has an aluminum electrolytic capacitor main body having a pair of electrode terminals, and a safety device connected to one of the pair of electrode terminals, and the threshold voltage is set between the aluminum electrolytic capacitor and the aluminum electrolytic capacitor body. An aluminum electrolytic capacitor characterized by connecting a varistor whose surge voltage is approximately equal to the capacitor's surge voltage.