JPH0412517A - Aluminum electrolytic capacitor - Google Patents

Abstract

PURPOSE:To avoid the running of a driving electrolyte gas out of the title aluminum electrolytic capacitor by a method wherein an emergency increase in inner pressure of a metallic case is detected by a pressure-voltage converting element to cut off the electric circuit of the capacitor. CONSTITUTION:When the inner pressure of a metallic case 2 is increased by a driving electrolyte gasified by heating, before actuating a safety device such as an exprosion-proof valve etc., the increase in the inner pressure of the metallic case 2 is detected by a pressure-voltage converting element 6 to be converted into an electric signal thereby cutting off the electric circuit of a capacitor 1. Accordingly, the unnecessary actuation of said safety device due to the increase in pressure can be prevented. Through these procedures, the running of the driving electrolyte gas out of the title aluminum electrolytic capacitor can be avoided.

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 inside an aluminum case.

When this aluminum electrolytic capacitor is used at an overvoltage higher than the rated voltage, the temperature of the driving electrolyte contained in the capacitor element rises and vaporizes, causing the internal pressure of the aluminum case to rise. 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, in this type of aluminum electrolytic capacitor, a weak point is usually provided in the sealing member or aluminum case, and when the internal pressure of this aluminum case rises abnormally, the weak point breaks and the driving electrolyte in the aluminum cane leaks. Because the gas flows to the outside, a large explosion will not occur.

Problems to be Solved by the Invention However, in the above-mentioned conventional aluminum electrolytic capacitors, gas from the drive electrolyte leaks out of the capacitor, resulting in dirt inside the equipment in which the aluminum electrolytic capacitors are installed, and a risk of fire. The problem was that it was indistinguishable from smoke caused by 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 comprises: a capacitor element impregnated with a driving electrolyte; a bottomed cylindrical metal case in which the capacitor element is housed;
a pair of lead wires derived from the capacitor element;
A pair of external connection terminals connected to the pair of lead wires and a sealing member sealing the opening of the metal case are provided, and a pressure-voltage conversion element is installed in the sealing member or the metal case, and The pressure-voltage converting element detects the pressure rise inside the metal case at the same time, converts it into an electrical signal, and uses this electrical signal to interrupt the electrical circuit of the capacitor.

Function: According to the aluminum electrolytic capacitor having the above configuration, a sealing member sealing the opening of the metal case or a pressure-voltage conversion element is installed inside the metal case, so that the aluminum electrolytic capacitor is protected from overvoltage exceeding the rated value. When applied, the leakage current gradually increases, and the temperature of the capacitor element inside the metal case rises due to Joule heat caused by the driving electrolyte and the resistance of the dielectric oxide and film. And due to this fever,
The drive electrolyte gasifies and the pressure inside the metal case rises, eventually activating safety devices such as explosion-proof valves. However, in the present invention, before the safety devices such as explosion-proof valves operate,
The pressure rise inside the metal case is detected by the pressure-voltage conversion element and converted into an electrical signal, and the electrical circuit of the capacitor is cut off by this electrical signal, so that the pressure rise inside the metal case is detected. Activation of safety devices such as anti-drying valves can also be prevented.
This prevents the driving electrolyte gas from leaking out of the aluminum electrolytic capacitor.

Embodiment Hereinafter, one embodiment of the present invention will be described based on the accompanying drawings. In Figure 1, 1 is an aluminum electrolytic capacitor 7' (
Rating: 200V, 680μF) (7) Koni/7'Nsa Shiko, this capacitor element 1 is constructed by forming a dielectric oxide film on the surface of a roughened aluminum foil and winding this together with a separator. ing. This capacitor element 1 is impregnated with a driving electrolyte and is installed in a bottomed cylindrical metal case 2 made of aluminum. Further, a pair of leads M3.3& made of aluminum are led out from the capacitor element 1, and this pair of leads M3. A pair of external connection terminals 4.4a are connected to 3.31L by caulking at a portion of the sealing member 5 made of a terminal plate.

The sealing member 5 made of the terminal plate is disposed at the opening of the metal case 2, and seals the opening of the metal case 2 by curling the open end of the metal case 72.

Further, a pressure-voltage conversion element 6 such as a piezoelectric element is installed in the central hollow part 1a of the same part of the capacitor element 1, and this pressure-voltage conversion element 6 has a device for extracting a signal to the outside. A pair of lead wires 7.7& are connected to each other, and further connected to a pair of lead terminals 8, 8a through the sealing member 5.

The aluminum electrolytic capacitor with the above configuration is set so that the electric circuit is cut off when the voltage across the pressure-redundant pressure conversion element 6 exceeds a certain level. Overvoltage, Tsuma! +3
When an overvoltage of 60V is applied, the leakage f''L current gradually increases, and the temperature of the capacitor element 1 inside the metal case 2 increases due to the juice/L/P due to the resistance of the driving electrolyte and the dielectric oxide film. Due to this heat generation, the drive electrolyte gasifies and the pressure inside the metal cake 2 increases.In this case, the pressure-voltage conversion element 6 such as a piezoelectric element detects the pressure increase and converts it into an electrical signal. This electrical signal is a voltage across the pair of lead terminals 8, 8a that allows the pressure inside the metal case 2 to be taken out to the outside as an alarm signal in the event of an abnormality. It was possible to open the electric circuit by forcibly cutting off both ends of the pair of external connection terminals 4.4a of the capacitor.

FIG. 2 shows another embodiment of the present invention, in which a pressure-voltage conversion element 6 such as a piezoelectric element in FIG. 1 is installed in the sealing member 5. In this embodiment, the same effects as in the embodiment shown in FIG. 1 were obtained.

Effects of the Invention As is clear from the description of the embodiments above, the aluminum electrolytic capacitor of the present invention has a pressure-voltage converting element installed in the sealing member or the metal case, and converts the pressure increase inside the metal case during an abnormality into the pressure. - Since the voltage is detected by a voltage conversion element and converted into an electrical signal, and the electrical circuit of the capacitor is cut off by this electrical signal, safety devices such as explosion-proof valves may be activated due to pressure increase inside the metal case. This can reliably prevent the gas of the driving electrolyte from flowing out of the aluminum electrolytic capacitor.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an aluminum electrolytic capacitor showing one embodiment of the invention, and FIG. 2 is a sectional view of an aluminum electrolytic capacitor showing another embodiment of the invention. 1...Capacitor element, 2...Metal case, 3゜3a...Pair of lead wires, 4.4a
. . . A pair of external connection terminals, 5 . . . Sealing member, 6 . . . Pressure-voltage conversion element. Name of agent: Patent attorney Shigetaka Awano and one other person Figure 7 Capacitor element 24: Fake booth tJ--71 lead 4.4a, -f=7 outside view, restaurant hsuf Diamond stroke 0 part 6 Pressure - fFLi 按:! Tef, Te, +1 wheel, metal case, 1 saw, 16-grid, 1 axis, shoulder strap, Y1, 10 hands, 10,000 car voltage, 61'+

Claims (1)

[Claims] A capacitor element impregnated with a driving electrolyte, a bottomed cylindrical metal case housing the capacitor element, a pair of lead wires led out from the capacitor element, and a pair connected to the pair of lead wires. external connection terminal,
and a sealing member that seals the opening of the metal case,
A pressure-voltage conversion element is installed in the sealing member or the metal case, and the pressure-voltage conversion element detects the pressure increase inside the metal case during an abnormality and converts it into an electrical signal. An aluminum electrolytic capacitor designed to interrupt the electrical circuit of