JP2003031447A - Electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrolytic capacitor in which action of a safety mechanism can be judged visually when an overvoltage is applied and driving electrolyte is gasified to open an explosion-proof valve. SOLUTION: A capacitor element 1 impregnated with electrolyte is contained in a bottomed metal case 2 having an opening sealed with a sealing material 5 an the electrolytic capacitor body having an explosion-proof valve 6 formed on the metal case 2 or the sealing material 5 is contained in a bottomed exterior case 7 through a space. In such an electrolytic capacitor having double case structure, a window of transparent resin 8 is made at a part of the exterior case 7 and a temperature indicating material 9 changing the color at the vaporization point of the electrolyte is disposed on the inside of the window. The sealing material 5 comprises a positive terminal and a negative terminal connected, respectively, with a positive lead and a negative lead led out from the capacitor element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic capacitor having a double case structure.

[0002]

2. Description of the Related Art Generally, an aluminum electrolytic capacitor is wound with an aluminum foil having a dielectric oxide film formed on its surface and electrolytic paper to form a capacitor element, and this capacitor element is placed in an aluminum case together with a driving electrolytic solution. It was configured by encapsulating in.

When an overvoltage higher than the rating is applied to the aluminum electrolytic capacitor, the temperature of the driving electrolyte impregnated in the capacitor element rises and vaporizes, so that the internal pressure of the aluminum case rises. 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 may come off from the aluminum case.

Therefore, in this type of aluminum electrolytic capacitor, a weak point is usually provided in the aluminum case, and when the internal pressure of the aluminum case rises abnormally, the explosion-proof valve provided in the aluminum case opens. Since the gas of the driving electrolyte in the aluminum case flows out to the outside, it becomes electrically open and does not cause short circuit or ignition.

However, in the above-mentioned conventional aluminum electrolytic capacitor, since the gas of the driving electrolytic solution flows out to the outside of the capacitor, the inside of the device in which the aluminum electrolytic capacitor is set becomes dirty, and it is distinguished from smoke caused by flame. It had a problem that it did not come out.

In order to solve the above problems, there is a double structure in which the entire aluminum electrolytic capacitor is housed in a case as shown in FIGS.

In the aluminum electrolytic capacitor shown in FIG. 3, the internal lead wires 4a and 4b between the metal case 2 and the outer case 7 which are separate from each other are connected as fuse wires, so that the explosion-proof valve 6 opens due to an abnormal voltage. Then, since the internal electrolytic capacitor moves to the bottom side together with the metal case due to the pressure increase, the fuse wire is cut, the generated gas and the electrolytic solution do not scatter to the surroundings, and the short circuit or the ignition does not occur.

Further, the aluminum electrolytic capacitor shown in FIG.
A separate outer case 7 having a cylindrical shape with a bottom is arranged outside the metal case 2 accommodating the elements, and an absorbing material 10 having a property of absorbing the driving electrolytic solution is provided on the inner surface of the separate outer case 7. The outer case 7 is arranged and the opening of the separate outer case 7 is curled and sealed. According to this configuration, when the explosion-proof valve 6 opens during an abnormality, the drive electrolyte ejected from the explosion-proof valve portion can be absorbed by the absorber 10.
Also, even if this driving electrolyte is cooled and liquefied,
Since the opening of the separate outer case 7 having a bottomed cylindrical shape is curling-sealed, the liquefied driving electrolytic solution is stored between the separate outer case and the metal case 2 located inside thereof. Therefore, the driving electrolyte does not leak outside.

[0009]

However, in the conventional aluminum electrolytic capacitor as described above, since it is covered with a separate outer case, an overvoltage is applied, the explosion-proof valve opens, and the internal safety mechanism is formed. Even if it works, there is a problem in that there is no change in the appearance of the outer case, and it is difficult to determine whether the explosion-proof valve has opened and the safety mechanism has worked. Therefore, it is difficult to check the aluminum electrolytic capacitor and the like built into the device because it is difficult to check the electrical characteristics.

The present invention solves the above problems,
To provide an electrolytic capacitor having a double-case structure that can be visually recognized even when overvoltage is applied, the driving electrolytic solution is gasified, and the explosion-proof valve is opened to operate the safety mechanism. With the goal.

[0011]

To achieve the above object, in an electrolytic capacitor of the present invention, a capacitor element impregnated with an electrolytic solution is housed in a metal case, and the opening of the metal case is sealed with a sealing material. In an electrolytic capacitor having a double case structure in which an electrolytic capacitor body having an explosion-proof valve formed in the metal case or the sealing material is housed in the outer case with a certain space, the outer case is partially transparent. It is characterized in that a window made of resin is formed, and a temperature indicating material that changes color at the vaporization temperature of the electrolytic solution is arranged inside the window.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) FIG. 1 is a sectional view showing a first embodiment of an electrolytic capacitor of the present invention. In FIG. 1, reference numeral 1 is a capacitor element, and this capacitor element 1
Is formed by forming a dielectric oxide film on the surface of a roughened aluminum foil and winding it together with a separator. The capacitor element 1 is impregnated with a driving electrolytic solution, and the capacitor element 1 is mounted in a bottomed cylindrical metal case 2 made of aluminum. Further, a pair of lead wires 3a, 3b made of aluminum are led out from the capacitor element 1, and a pair of fuse wires 4a, 4b are formed on the pair of lead wires 3a, 3b at a portion of a sealing member 5 made of a terminal plate. Connected by caulking. The sealing member 5 made of the terminal plate is arranged in the opening of the metal case 2 and seals the open end of the metal case 2. An explosion-proof valve 6 made of a thin portion which is a weak point is formed at the sealing portion of the metal case 2.

A separate outer case 7 having a bottomed cylindrical shape is arranged outside the metal case 2, and the opening of the outer case 7 is sealed by a sealing member 11. Further, a window 8 made of a transparent resin is provided in a part of the outer case 7, and a temperature indicating material 9 which changes its color by the vaporization temperature of the electrolytic solution is arranged inside the window 8. An irreversible thermolabel manufactured by NOF Giken Co., Ltd. may be used as the temperature indicator.

The operation of the electrolytic capacitor having the above structure will be described. When an overvoltage or the like higher than the rated value is applied to this electrolytic capacitor, the internal pressure of the metal case 2 rises, whereby the explosion-proof valve 6 provided at the sealing portion of the metal case 2 operates and the gas generated therein is ejected. . At this time, since the generated gas is ejected into the upper space between the metal case 2 and the outer case 7, the pressure inside the upper space causes the electrolytic capacitor inside the metal case 2 to move.
And move to the bottom side. Along with this, the fuse wire 4a
Or 4b is cut. Further, when the internal pressure rises and the generated gas is ejected, the temperature of the temperature indicator 9 changes because the condenser is in a high temperature state.

(Second Embodiment) FIG. 2 is a sectional view showing a second embodiment of the electrolytic capacitor of the present invention. In FIG. 2, components having the same functions as those of the components shown in FIG. 1 are designated by the same reference numerals.

In FIG. 2, reference numeral 1 is a capacitor element having a structure similar to that of the first embodiment.
It is installed in a bottomed cylindrical metal case 2 made of aluminum. A pair of lead wires 3a, 3b made of aluminum are led out from the capacitor element 1, and a pair of external terminals are connected to the pair of lead wires 3a, 3b by caulking at a sealing member 5 portion made of a terminal plate. ing.
The sealing member 5 made of a terminal plate is arranged in the opening of the metal case 2 and seals the open end of the metal case 2. An explosion-proof valve 6 made of a thin portion which is a weak point is formed on the top plate of the metal case 2.

A separate outer case 7 having a cylindrical shape with a bottom is disposed outside the metal case 2, and an absorbent material 10 having a property of absorbing the driving electrolytic solution is provided on the inner surface of the outer case 7. This separate outer case 7 is installed.
The opening is closed at the portion of the sealing member 5 of the metal case 2 by curling. In addition, in a part of the outer case 7,
A window 8 made of a transparent resin is provided, and a temperature indicating material 9 that changes color at the vaporization temperature of the electrolytic solution is arranged inside the window 8. Similar to the first embodiment, when the internal pressure rises and the generated gas is ejected, the temperature of the temperature indicator 9 changes because the condenser is in a high temperature state.

[0019]

As described above, according to the present invention,
When the explosion-proof valve operates due to abnormal stress such as overvoltage applied to the electrolytic capacitor, the temperature indicator can be observed in the transparent resin window attached to a part of the outer case of the double case structure, and the appearance of the explosion-proof valve can be observed. You can judge. Therefore, even if it is mounted on the device, it is possible to easily determine the replacement.

[Brief description of drawings]

FIG. 1 is a sectional view of an electrolytic capacitor according to a first embodiment of the present invention.

FIG. 2 is a sectional view of an electrolytic capacitor according to a second embodiment of the present invention.

FIG. 3 is a diagram illustrating a conventional example.

FIG. 4 is a diagram illustrating a conventional example.

[Explanation of symbols]

1 Capacitor element 2 metal cases 3a, 3b a pair of lead wires 4a, 4b A pair of fuse wires 5,11 Sealing member 6 Explosion-proof valve 7 Separate outer case 8 windows 9 Temperature indicator 10 absorber

Claims (2)

[Claims] 1. An electrolytic capacitor in which a capacitor element impregnated with an electrolytic solution is housed in a metal case, the opening of the metal case is sealed with a sealing material, and an explosion-proof valve is formed on the metal case or the sealing material. In an electrolytic capacitor having a double case structure in which a main body is housed in an outer case with a certain space, a window made of a transparent resin is formed in a part of the outer case, and the electrolytic solution is vaporized inside the window. An electrolytic capacitor characterized by arranging a temperature indicator that changes color with temperature. 2. The electrolytic capacitor according to claim 1, wherein the sealing material includes an anode terminal and a cathode terminal respectively connected to an anode lead and a cathode lead drawn out from the capacitor element. Electrolytic capacitor.