JPH04101408A - Aluminum electrolytic capacitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an aluminum electrolytic capacitor used in general electronic equipment.

Conventional technology This type of conventional aluminum electrolytic capacitor is made by winding an anode foil and a cathode foil, which are made by forming a dielectric oxide film on the surface of a roughened aluminum foil by anodizing, together with a separator, to form a capacitor element. The capacitor element is impregnated with a driving electrolyte, and then the capacitor element is enclosed in a metal case made of aluminum.

When this aluminum electrolytic capacitor is used at an overvoltage higher than the rated voltage, the temperature of the driving electrolyte impregnated in the capacitor element rises and vaporizes, so that the internal pressure of the metal case rises. 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, this type of aluminum electrolytic capacitor usually has a weak point made of a thin wall on the top of the metal case, and when the internal pressure of this metal case rises abnormally, the weak point breaks and the inside of the metal case is broken. The gas from the driving electrolyte will flow out, so a major explosion will not occur.

Problems to be Solved by the Invention However, 1. In conventional aluminum electrolytic capacitors, gas from the driving electrolyte leaks out of the capacitor, so the inside of the equipment in which this aluminum electrolytic capacitor is installed may become dirty. The problem was that it was indistinguishable from smoke caused by flames.

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 temperature sensing element is attached to one of the pair of external connection terminals. It is fixed by a fixing means, and a temperature sensing element detects the heat generated by the external connection terminal due to a temperature rise inside the metal case in the event of an abnormality, transmits a detection signal from this temperature sensing element to the outside, and uses that signal to control the electrical circuit of the capacitor. It was designed to block it. As a fixing means for fixing the temperature sensing element to one of the pair of external connection terminals, a springy metal fitting, adhesive tape, resin or heat shrink tube is used, and either of these is used.
A temperature sensing element is fixed to one external connection terminal.

Function According to the aluminum electrolytic capacitor having the above configuration, a springy metal fitting, adhesive tape, resin, or heat-shrink tube can be used as a fixing means for fixing the temperature sensing element to one of the pair of external connection terminals. Since the temperature sensing element is fixed to the external connection terminal using either of these, if an overvoltage higher than the rated voltage is applied to this aluminum electrolytic capacitor, the leakage current will increase and the driving electrolyte will drain. The temperature of the capacitor element inside the metal case rises due to Joule heat due to the resistance of the dielectric oxide film and the resistance of the dielectric oxide film. In this case, since the lead wire led out from the capacitor element has very good thermal conductivity, the external connection terminal connected to this lead wire generates heat approximately equal to the internal temperature of the metal case. This heat generation is then detected by a temperature sensing element fixed to the external connection terminal.
The detection signal of this temperature-sensitive element is transmitted to the outside, and the signal immediately shuts off the capacitor's electrical circuit, thereby preventing the activation of safety devices such as explosion-proof valves due to an increase in the internal pressure of the metal case. This prevents the gas of the driving electrolyte from leaking out of the aluminum electrolytic capacitor.

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 winding an anode foil and a cathode foil, which are made by forming a dielectric oxide film on the surface of a roughened aluminum foil by anodizing, together with a separator. It is composed of: After impregnating the capacitor element 1 with a driving electrolyte, the capacitor element 1 is installed in a bottomed cylindrical metal case 2 made of aluminum. A pair of lead wires 3, 3a made of aluminum are led out from the capacitor element 1, and a pair of external connection terminals 44a are connected to the lead wires 3, 3a by caulking at a portion of the sealing member 5 made of a terminal plate. It is connected. 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 2. Further, among the pair of external connection terminals 4, 4a, one of the external connection terminals 4 is provided with a fixing means 6 made of adhesive tape or resin.
This fixes the temperature sensing element 7 having a pair of external connection lead wires 7a and 7b. Note that as the temperature sensing element 7, a temperature fuse, a thermistor, a thermocouple, a bimetal temperature sensing reed switch, etc. are normally used. In this case, when a temperature fuse is used as the temperature sensing element 7, a main body temperature sensing type temperature fuse using ceramic as a temperature sensing element may be used.

In the above configuration, the operation will be explained. When an overvoltage higher than the rated voltage is applied to this aluminum electrolytic capacitor, the leakage current increases, and the temperature of the capacitor element 1 inside the metal case 2 rises due to Joule heat due to the resistance of the driving electrolyte and dielectric oxide film. do. In this case, since the lead wires 3, 3a led out from the capacitor element 1 have very good thermal conductivity, the external connection terminals 4, 4a connected to the lead wires 3, 3a are connected to the internal temperature of the metal case 2. Generates almost the same amount of heat. Then, this heat generation is detected by a temperature sensing element 7 fixed to one of the external connection terminals 4, a detection signal of this temperature sensing element 7 is transmitted to the outside, and the electric circuit of the capacitor is immediately interrupted by the signal. It is.

2, 3, 4, and 5, a springy metal fitting 6a is used to connect the temperature sensing element 7 to one external connection terminal 4.
Fig. 6 shows an example of fixing the temperature sensing element 7 to one of the external connection terminals 4 using a heat shrink tube 6b. It is something.

Using the fixing means 6 made of adhesive tape or resin shown in FIGS. 1, 2, 3, 4, 5, and 6, the metal fittings 6a having spring properties, and the heat shrink tube 6b, By fixing the temperature sensing element 7 to one of the external connection terminals 4, the temperature sensing element 7 can be easily fixed at low cost.

Effects of the Invention As is clear from the description of the embodiments above, the aluminum electrolytic capacitor of the present invention has a temperature-sensing function on one of the pair of external connection terminals connected to the pair of lead wires led out from the capacitor element. Because the element is fixed, if an overvoltage higher than the rated voltage is applied to this aluminum electrolytic capacitor, leakage current will increase and Joule heat due to the resistance of the drive electrolyte and dielectric oxide film will cause damage to the inside of the metal case. The temperature of the capacitor element will rise, and in this case, the lead wire calculated from the capacitor element has very good thermal conductivity, so the external connection terminal connected to this lead wire will raise the internal temperature of the metal case. This heat generation is detected by the temperature sensing element fixed to the external connection terminal, the detection signal of this temperature sensing element is transmitted to the outside, and the electric circuit of the capacitor is immediately connected by that signal. This prevents the activation of safety devices such as explosion-proof valves due to an increase in the internal pressure of the metal case, which prevents the drive electrolyte gas from leaking outside the aluminum electrolytic capacitor. Things will go away.

In addition, adhesive tape, resin, spring metal fittings, or heat shrink tubes are used as the fixing means for fixing the thermosensor to one of the external connection terminals, making it cheaper to fix the thermosensor. This can be done easily.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of an aluminum electrolytic capacitor showing an embodiment of the present invention, and Figs. 2 to 5 are perspective views showing the same aluminum electrolytic capacitor in which a temperature sensing element is fixed with a metal fitting having spring properties. , FIG. 6 is a perspective view showing the same aluminum electrolytic capacitor in which a temperature sensing element is fixed with a heat shrink tube. 1...Capacitor element, 2...Metal case, 3.3a...Pair of lead wires, 4,4a...
...Pair of external connection terminals, 5...Sealing member, 6...Fixing means, 6a...Metal fittings having spring properties, 6b...・・Heat shrink tube, 7
・・・・・・Temperature sensing element. Name of agent: Patent attorney Shigetaka Awano and 1 other person (Fig. 1)] l-Cosoton agent Goko 2 Metal case J, 3α°-Female size Noriichi Dome Izumi, 6 fixed + stage 7, 廠Onmiji Temple 3 Fig. 4 Terminal 6α for connecting shoes 6α Spring I-ke 5 metal fittings γ Kayakura 4-1-4 Iku Jikkyo-cho l Cα・Spring・1 life and 5 metal fittings 7 Kai-on #pre-Fig. 5 4” Tato Kaku offering earth use standing threat + 6a Changne = l'l and breaking 6 metal fittings 7 Gekijikai element 6b Heat shrinkage +1-bu 7 Special temperature element

Claims (5)

[Claims] (1) A capacitor element impregnated with a driving electrolyte, a bottomed cylindrical metal case housing the capacitor element,
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 temperature sensing element is attached to one of the pair of external connection terminals. It is fixed by a fixing means, and a temperature sensing element detects the heat generated by the external connection terminal due to a temperature rise inside the metal case in the event of an abnormality, transmits a detection signal from this temperature sensing element to the outside, and uses that signal to control the electrical circuit of the capacitor. Aluminum electrolytic capacitor designed to cut off. (2) A metal fitting with spring properties is used as a fixing means for fixing the temperature sensing element to one of the pair of external connection terminals, and the temperature sensing element is placed between this metal fitting and one of the external connection terminals. An aluminum electrolytic capacitor according to claim 1, which is sandwiched and fixed. (3) The aluminum electrolytic capacitor according to claim 1, wherein an adhesive tape is used as a fixing means for fixing the temperature sensing element to one of the pair of external connection terminals. (4) The aluminum electrolytic capacitor according to claim 1, wherein a resin is used as a fixing means for fixing the temperature sensing element to one of the pair of external connection terminals. (5) The aluminum electrolytic capacitor according to claim 1, wherein a heat-shrinkable tube is used as a fixing means for fixing the temperature sensing element to one of the pair of external connection terminals.