JPH04233214A - Aluminum electrolytic capacitor - Google Patents

Abstract

PURPOSE:To prevent the gas of driving electrolyte from flowing out, by installing a temperature detecting element on an aluminum rivet for fixing a pair of metal terminals to an aperture sealing plate, which terminals are connected with a pair of leading-out lead wires led out from a capacitor element. CONSTITUTION:When an excessive voltage higher than or equal to a rated voltage is applied to an aluminum electrolytic capacitor, the leak current of a capacitor element 11 increases, and the internal temperature of an armoring case 16 rises, on account of Joule heat due to the resistance of driving electrolyte and a dielectric oxide film. The heat of the temperature rise is conducted to an aluminum rivet 15, via a pair of leading-out lead wires, and detected by a temperature detecting element 18 fixed on the aluminum rivet. The detected signal of the element 18 is sent to the outside, and the electric circuit of the capacitor is cut off by the external signal. Thereby the gas of driving electrolyte can be prevented from flowing out to the outside.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum electrolytic capacitor used in general electronic equipment.

0002

2. Description of the Related Art A conventional aluminum electrolytic capacitor of this type was constructed as shown in FIGS. 4a and 4b. That is,
An anode foil formed by roughening a high-purity aluminum foil to increase its surface area and forming a dielectric oxide film on the surface by anodizing the surface, and a cathode foil made of aluminum foil are attached with lead leads 1, and the anode foil A capacitor element 2 is constructed by winding the cathode foil together with electrolytic paper and impregnating it with a driving electrolyte, and the lead 1 of this capacitor element 2 is connected to a metal terminal 4 attached to a sealing plate 3 with an aluminum rivet 5. At the same time as caulking the connection, the capacitor element 2 is housed in a bottomed cylindrical metal case 6 made of aluminum, and then the sealing plate 3 is attached to the opening of the metal case 6 to seal it. An aluminum electrolytic capacitor was constructed by covering the outer surface with a sleeve 7 made of vinyl chloride.

[0003] When this aluminum electrolytic capacitor is used at a voltage higher than the rated voltage, the capacitor element 2
Since the temperature of the driving electrolyte impregnated in the metal case 6 rises and vaporizes, the internal pressure of the metal case 6 rises. In this case, if the internal pressure of the metal case 6 exceeds the sealing force between the metal case 6 and the sealing plate 3, the capacitor element 2 will come off from the metal case 6 and fly out, or the metal case 6 will jump, which is very dangerous. It becomes a state. Therefore, in this type of aluminum electrolytic capacitor, a weak point is usually provided in the bottomed part of the metal case 6 to serve as a safety valve (not shown), and when the internal pressure of the metal case 6 rises abnormally, the safety valve is activated. Since the gas of the driving electrolyte in the metal case 6 flows out from this safety valve, a dangerous explosion will not occur.

0004

[Problems to be Solved by the Invention] However, in the conventional aluminum electrolytic capacitor described above, when the internal pressure of the metal case 6 rises abnormally, the safety valve is activated and the gas of the driving electrolyte flows out of the capacitor. Because of this,
There were problems in that the inside of the equipment in which the aluminum electrolytic capacitor was installed became dirty, and it was difficult to distinguish it from smoke caused by a fire.

The present invention solves the above-mentioned conventional problems, and aims to provide an aluminum electrolytic capacitor that can prevent the gas from the driving electrolyte from flowing out.

[0006]

[Means for Solving the Problems] In order to solve the above problems, the aluminum electrolytic capacitor of the present invention includes a capacitor element having a pair of lead-out leads, and a bottomed cylindrical exterior with the capacitor element internally inserted through an opening at one end. It has a case, a sealing plate that seals an opening at one end of the outer case, and a pair of metal terminals that are attached to the sealing plate with aluminum rivets and connected to the pair of lead-out leads. A temperature sensing element is placed on an aluminum rivet on one of the metal terminals, and a metal lid is placed on this one metal terminal to enclose the temperature sensing element, and an opening at one end of the outer case is placed on the aluminum rivet of one of the metal terminals. The metal lid is held down and fixed with a resin cap placed on the side, and the temperature rise due to heat generation of the capacitor element inside the outer case is detected by the temperature sensing element via the aluminum rivet in the event of an abnormality. A detection signal is transmitted to the outside, and the electric circuit of the capacitor is cut off by the external signal.

[0007]

[Function] According to the aluminum electrolytic capacitor having the above configuration, the temperature sensing element is mounted on the aluminum rivet that attaches the pair of metal terminals connected to the pair of lead-out leads led out from the capacitor element to the sealing plate. When an overvoltage higher than the rated voltage is applied to this aluminum electrolytic capacitor, the leakage current of the capacitor element increases, the internal temperature of the outer case rises due to Joule heat due to the resistance of the drive electrolyte and the dielectric oxide film, and This heat is conducted to the aluminum rivet via a pair of lead-out leads in the capacitor element, and is detected by a temperature sensing element attached to the aluminum rivet, and the detection signal of this temperature sensing element is sent to the outside. The electric circuit of the capacitor is immediately cut off by the external signal, which prevents the safety valve from operating due to the rise in internal pressure of the outer case. There will be no leakage.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. In the figure, 11 is a capacitor element, and this capacitor element 11 consists of an anode foil made by roughening a high-purity aluminum foil to enlarge its surface area, and forming a dielectric oxide film on the surface by anodizing, and an aluminum foil. A pair of lead-out leads 12 are attached to the cathode foil, and the anode foil and the cathode foil are wound together with electrolytic paper,
And it is constructed by impregnating it with a driving electrolyte. A pair of lead-out leads 12 led out from this capacitor element 11 are caulked and connected to a pair of metal terminals 14 attached to a sealing plate 13 with aluminum rivets 15, and the capacitor element 11 is connected to a bottomed cylindrical aluminum plate. After that, the sealing plate 13 is attached to the opening of the outer case 16, and the opening end of the outer case 16 is curled to the flat part of the sealing plate 13 to seal it. The outside of the case 16 is covered with a resin sleeve 17 made of vinyl chloride or the like.

Furthermore, a temperature sensing element 18 is mounted on the aluminum rivet 13 of one of the pair of metal terminals 14 as shown in FIGS. A lid 19 made of metal such as aluminum is disposed to enclose the temperature sensing element 18, and a cap 20 made of resin is placed over the opening of one end of the outer case 16.
The metal lid 19 is pressed and fixed.

When an overvoltage higher than the rated voltage is applied to the aluminum electrolytic capacitor configured as described above, the leakage current of the capacitor element 11 increases, and the Joule heat due to the resistance of the driving electrolyte and the dielectric oxide film causes the outer case 16 to increase. The internal temperature of the capacitor element 11 increases, and the heat caused by this temperature rise is conducted to the aluminum rivet 15 via a pair of lead-out leads 12 in the capacitor element 11, and this heat is transferred to the temperature sensing element attached above the aluminum rivet 15. 18 detected,
The detection signal of the temperature sensing element 18 is transmitted to the outside, and the electric circuit of the capacitor is interrupted by the external signal. In this way, when an overvoltage higher than the rated voltage is applied to the aluminum electrolytic capacitor, the electrical circuit of the capacitor is immediately cut off, so it is possible to prevent the safety valve from operating due to an increase in the internal pressure of the exterior case 16. This prevents the gas of the driving electrolyte from flowing out of the capacitor.

[0011]

[Effects of the Invention] As is clear from the description of the above embodiments,
The aluminum electrolytic capacitor of the present invention has a temperature-sensitive element mounted on an aluminum rivet that attaches a pair of metal terminals connected to a pair of lead-out leads led out from a capacitor element to a sealing plate. When an overvoltage higher than the rated voltage is applied, the leakage current of the capacitor element increases, and the internal temperature of the outer case rises due to Joule heat due to the resistance of the drive electrolyte and dielectric oxide film, and this heat is transferred to the capacitor. The heat is conducted to the aluminum rivet via a pair of lead-out leads in the element, and this heat is detected by the temperature sensing element attached to the aluminum rivet.The detection signal of this temperature sensing element is transmitted to the outside, and the heat is transmitted to the outside. Since the electrical circuit of the capacitor is immediately cut off by the signal, it is possible to prevent the safety valve from operating due to an increase in the internal pressure of the external case, and as a result, the drive electrolyte gas leaks outside the capacitor. will disappear.

[Brief explanation of the drawing]

[Fig. 1] A cutaway front view of an aluminum electrolytic capacitor showing one embodiment of the present invention.

[Figure 2] Exploded perspective view of the aluminum electrolytic capacitor

[Figure 3]
(a) Exploded perspective view of the terminal part of the aluminum electrolytic capacitor (b) Perspective view of the terminal part

[Figure 4] (a) A plan view of a conventional aluminum electrolytic capacitor (b) A cutaway front view of the same aluminum electrolytic capacitor

[Explanation of symbols]

11 Capacitor element 12 A pair of drawer leads 13 Sealing plate 14 A pair of metal terminals 15 Aluminum rivet 16 Exterior case 18 Temperature sensing element 19 Metal lid 20 Resin cap

Claims (1)

[Claims] Claims 1: A capacitor element having a pair of lead leads, a bottomed cylindrical outer case in which the capacitor element is inserted from an opening at one end, a sealing plate for sealing the opening at one end of the outer case, and a sealing plate for sealing the opening at one end of the outer case. A pair of metal terminals are attached to the plate with aluminum rivets and connected to the pair of lead-out leads, and a temperature sensing element is placed on the aluminum rivet of one of the pair of metal terminals. Further, a metal lid is disposed on one of the metal terminals so as to enclose the temperature sensing element, and the metal lid is pressed and fixed with a resin cap that is placed over one end of the opening of the outer case. In the event of an abnormality, the temperature rise due to heat generated by the capacitor element inside the exterior case is detected by a temperature sensing element via an aluminum rivet, the detection signal of the temperature sensing element is transmitted to the outside, and the electric circuit of the capacitor is cut off by the external signal. An aluminum electrolytic capacitor characterized by: