JPH0653091A - Electrolytic capacitor - Google Patents

Abstract

PURPOSE:To use an electrode foil with a higher capacitance and at the same time to reduce the space inside an armored case by constituting the armored case with a built-in capacitor element using iron and providing a sealing body at an opening. CONSTITUTION:A capacitor element 12 is incorporated in a closed-end cylindrical or flat iron armored case and the opening of the armored case 11 is sealed by a sealing body 13. Since the iron armored case is strong than an aluminum armored case, the iron armored case can endure, for a long time, pressure increase due to aging of an electrolytic capacitor or hydrogen gas, etc., which is generated on operation, thus using an electrode foil with a larger capacity than that of a conventional one, reducing the space inside the armored case 11, and then further miniaturizing the electrolytic capacitor.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Recently, with downsizing and high reliability of electronic equipment, electrolytic capacitors used in the electronic equipment are required to be downsized, thinned, and have a long life.

A conventional electrolytic capacitor of this type is shown in FIG.
As shown in (a) and (b), a separator is interposed between an anode foil and a cathode foil, and these are wound to form a capacitor element 1, and the capacitor element 1 is impregnated with an electrolytic solution. After that, the capacitor element 1 was housed in the aluminum case 2, and the opening of the aluminum case 2 was sealed with the sealing body 3.

[0004]

However, as shown in FIG.
In the conventional electrolytic capacitors shown in (a) and (b), if further downsizing, thinning, and long life are attempted in response to market demands, a defect in appearance occurs and reliability is impaired. There was a problem.

That is, in order to miniaturize the electrolytic capacitor, generally, an anode foil and a cathode foil having a high etching ratio and a high electrostatic capacity per unit area are used, and at the same time, the space inside the aluminum case 2 is minimized. The means for maximizing the areas of the anode foil and the cathode foil accommodated in the aluminum case 2 are taken in parallel, but if the above means is simply advanced, the capacity of the foil is increased. Along with this, the amount of hydrogen gas generated during aging or operation increases, so that the pressure inside the aluminum case 2 rises. In addition to this, when the space inside the aluminum case 2 is made smaller, the aluminum case 2 is further reduced. There is a problem that the internal pressure rises and the appearance of the electrolytic capacitor is impaired.

In order to make the electrolytic capacitor thinner, the flat capacitor element 1 as shown in FIG. 6 (b) is housed in a flat aluminum case 2, and the aluminum case 2 Although the opening is sealed with the sealing body 3, in such a structure, the strength is significantly lower than that of the cylindrical aluminum case 2 shown in FIG. In the case of the aluminum case 2, it is necessary to make the wall thickness thicker, and there is a problem that it is disadvantageous in terms of accommodating a high capacity and cost.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide an electrolytic capacitor which can be made smaller, thinner, and have a longer life.

[0008]

In order to achieve the above object, an electrolytic capacitor of the present invention comprises a capacitor element, an outer case containing the capacitor element, and a sealing body for sealing the opening of the outer case. The outer case is made of iron.

[0009]

According to the above construction, the outer case containing the capacitor element is made of iron. Since iron has higher tensile strength, compressive strength, bending strength, etc. than aluminum, it is made of iron. The electrolytic capacitor of the present invention using the external case described above can withstand a rise in pressure due to aging or hydrogen gas generated during operation for a long time without causing a defect in appearance,
As a result, it is possible to use the anode foil and the cathode foil having higher capacitance, and it is possible to further reduce the space inside the outer case.

In the conventional flat type outer case using aluminum, when the degree of flatness is increased,
Since the strength of the outer case drastically decreases due to the structure, the degree of flatness cannot be increased so much, which limits the thinning of the capacitor, but uses a flat outer case made of iron. As a result, the degree of flatness can be further increased as compared with the conventional aluminum case, and therefore, the electrolytic capacitor can be made smaller, thinner, and have a longer life.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIGS. 1 (a), 1 (b), 2, 3, and 4, reference numeral 11 designates a bottomed cylindrical or flat outer case in which the capacitor element 12 is built.
Is made of iron, and the opening of the iron outer case 11 is sealed by a sealing body 13.

In the iron outer case 11, the iron forming the outer case 11 is brought into contact with the electrolytic solution inside,
If you are exposed to an external corrosive environment,
The entire surface is covered with resin 14 as shown in FIG. 2, the entire surface is covered with aluminum plating 15 as shown in FIG. 3, and the entire surface is covered with aluminum clad 16 as shown in FIG. ing.

Next, 30 electrolytic capacitors according to the embodiment of the present invention and 30 electrolytic capacitors according to the related art are manufactured and the temperature is set to 105.degree.
FIG. 5 shows the results of examining the amount of appearance deformation by carrying out a high temperature load test.

As is clear from FIG. 5, the electrolytic capacitor A according to the embodiment of the present invention has the outer case 11 made of iron, and this iron is made of aluminum which constitutes the outer case of the conventional electrolytic capacitor. Because it is stronger than
The electrolytic capacitor can withstand a long period of time even when the electrolytic capacitor is aged or the pressure is increased due to hydrogen gas or the like generated during operation. Therefore, almost no deformation of the external appearance of the electrolytic capacitor is recognized. As described above, in the electrolytic capacitor A according to the embodiment of the present invention, the outer case 11 has a higher proof strength against the internal rising pressure, so that a higher capacity electrode foil can be used than ever. At the same time, it is possible to reduce the space inside the outer case 11, which allows the electrolytic capacitor to be further downsized. At the same time, since the outer case 11 having a higher degree of flatness can be used, the electrolytic capacitor can be made thinner than the conventional one, and the electrolytic capacitor A of the embodiment of the present invention is the electrolytic case of the conventional example. It is clear that it is superior to the capacitor B.

[0016]

As described above, the electrolytic capacitor of the present invention comprises a capacitor element, an outer case containing the capacitor element, and a sealing body for sealing the opening of the outer case. This iron has a higher strength than aluminum that constitutes the conventional outer case, so even when the pressure rises due to hydrogen gas generated during aging of the electrolytic capacitor or during operation, It can withstand for a long time without causing any appearance defects, which allows the use of electrode foils with higher capacitance and the reduction of the space inside the outer case. It is possible to further downsize the electrolytic capacitor. At the same time, it is possible to use an outer case with a higher degree of flatness, so it is possible to make the electrolytic capacitor even thinner.
This makes the electrolytic capacitor smaller and thinner,
It is possible to realize a long life.

[Brief description of drawings]

FIG. 1A is a partially cutaway perspective view of a cylindrical electrolytic capacitor showing an embodiment of the present invention. FIG. 1B is a partially cutaway perspective view of the same flat type electrolytic capacitor.

FIG. 2 is a sectional view showing a state in which the entire surface of an outer case of the capacitor is covered with resin.

FIG. 3 is a sectional view showing a state in which the entire surface of an outer case of the capacitor is covered with aluminum plating.

FIG. 4 is a cross-sectional view showing a state where the entire surface of an outer case of the capacitor is covered with an aluminum clad.

FIG. 5 is a graph showing a comparison of the amount of external deformation at the 105 ° C. high temperature load test of the example of the present invention and the conventional example.

FIG. 6A is a partially cutaway perspective view showing a conventional cylindrical electrolytic capacitor. FIG. 6B is a partially cutaway perspective view showing a conventional flat type electrolytic capacitor.

[Explanation of symbols]

 11 Outer case 12 Capacitor element 13 Sealing body 14 Resin 15 Aluminum plating 16 Aluminum clad

Claims (4)

[Claims] 1. An electrolytic capacitor comprising a capacitor element, an outer case containing the capacitor element, and a sealing body for sealing an opening of the outer case, wherein the outer case is made of iron. 2. The electrolytic capacitor according to claim 1, wherein the outer case is covered with resin. 3. The electrolytic capacitor according to claim 1, wherein the surface of the outer case is coated with aluminum. 4. The electrolytic capacitor according to claim 1, wherein a surface of the outer case is covered with an aluminum clad.