JPH04323816A - Aluminum electrolytic capacitor - Google Patents

Abstract

PURPOSE:To improve the sealing work and to increase the airtightness. CONSTITUTION:As for a sealing member 10, a laminate which is constituted of fluorocarbon resin bodies 12a, 12b and a rubber elastic body 11 placed between the two fluorocarbon resin bodies 12a, 12b or a laminate which is constituted of at least three layers is used. With this sealing member 10, a recess 4a is formed on the outer face of the rubber elastic body 11 when a metal case 4 is tightened transversely.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to aluminum electrolytic capacitors, and more particularly to an improvement in the sealing member thereof.

0002

2. Description of the Related Art FIG. 3 shows a sectional view of a typical conventional aluminum electrolytic capacitor. That is, the electrolytic capacitor includes a capacitor element 1 formed by winding aluminum anode foil and cathode foil with a separator in between.

Tab terminals 2, 2 as lead terminals are attached to each foil of the capacitor element 1, and after the capacitor element 1 is impregnated with a predetermined electrolyte, the tab terminals 2
, 2 by inserting the sealing member 3 through the lead insertion holes 3a, 3a formed therein.

The capacitor element 1 is housed together with a sealing member 3 in a cylindrical metal case 4 with a bottom. A horizontal throttle groove 4a that engages with the side surface of the sealing member 3 is formed on the circumferential surface of the metal case 4, and an opening edge 4a of the metal case 4 is formed.
b is caulked against the sealing member 3.

By the way, the sealing member 3 is generally made of an elastic material such as butyl rubber, which has good sealing workability including ease of insertion into the tab terminal 2, but is highly volatile and swellable. It is highly permeable to electrolyte solution (paste) and is not preferred.

[0006]

SUMMARY OF THE INVENTION Therefore, as shown in FIG. 4, it has been proposed that the sealing member 3 be a two-layer laminate of a fluororesin body 5a and a rubber elastic body 5b. The fluororesin body 5a has sufficient chemical resistance to electrolytes,
Moreover, it has high airtightness.

In this two-layer laminate, there are two cases in which the fluororesin body 5a is placed inside the case and the rubber elastic body 5b is placed outside the case as shown in FIG. In some cases, the fluororesin body 5a is placed inside the case and the fluororesin body 5a is placed outside, but the following drawbacks have been pointed out in either case.

First, in the former case, since the fluororesin body 5a corresponds to the horizontal throttle groove 4a, it is necessary to form a concave groove in advance on the circumferential surface of the fluororesin body 5a to match the horizontal throttle groove 4a.
There is a problem with its processability.

On the other hand, in the latter case, the horizontal throttle groove 4a is formed in the rubber elastic body 5b, so the processing as in the former is not necessary. However, since the outer surface of the rubber elastic body 5b is pressed by the fluororesin body 5a, the rubber elastic body 5b expands only toward the inside of the case 4 due to the pressure when forming the horizontal throttle groove 4a. There is a possibility that mechanical stress that is undesirable in terms of characteristics may be applied to the element 1.

0010

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned conventional drawbacks, and its structural feature is that an anode foil and a cathode foil made of aluminum each have a lead terminal attached thereto. It includes a capacitor element wound through a separator, a sealing member attached to each lead terminal of the capacitor element so as to be inserted through the capacitor element, and a bottomed cylindrical metal case in which the capacitor element is housed together with the sealing member, In the aluminum electrolytic capacitor, a horizontal throttle groove is formed on the peripheral surface of the metal case to engage with a side surface of the sealing member, and an opening edge of the metal case is caulked to the sealing member. The sealing member includes a first sealing element made of a rubber elastic body disposed at a position corresponding to the horizontal aperture groove, and a second sealing element made of a fluororesin body attached to both surfaces of the first sealing element. have at least 3
It consists of a laminate of layers.

[0011] Based on this three-layer laminate, a third sealing element made of a rubber elastic body may be added on the second sealing element on the side where the opening edge of the metal case is caulked. .

0012

[Operation] According to the above structure, since the rubber elastic body is placed in the middle and the fluororesin bodies are attached to both sides of the rubber elastic body, the bulge of the rubber elastic body is suppressed by the fluororesin body when forming the horizontal throttle groove. become.

[0013] Therefore, it is possible to perform sealing with good sealing workability, sufficient airtightness, and excellent chemical resistance.

[0014]

Embodiment First, a first embodiment of the present invention will be described with reference to FIG. In addition, in the figure, the same parts as in the conventional example described earlier are given the same reference numerals.

According to the first embodiment, a sealing member 10 made of a three-layer laminate is provided. That is, the sealing member 10 is composed of a rubber elastic body 11 disposed in the middle as a first sealing element, and fluororesin bodies 12a and 12b laminated on both sides of the rubber elastic body 11 as a second sealing element. There is.

The rubber elastic body 11 may be made of, for example, butyl rubber as in the prior art, and its thickness is preferably approximately equal to the width of the lateral throttle groove 4a formed in the metal case 4.

For example, tetrafluoroethylene resin is used for the fluororesin bodies 12a, 12b.
It is preferable that b and the rubber elastic body 11 are integrally laminated using an adhesive or lamination (tetra-etch).

This sealing member 10 has a pair of lead insertion holes 1.
0a, 10a, and is attached to the capacitor element 1 by inserting tab terminals 2, 2 as lead terminals therein.

This sealing member 10 is housed in a metal case 4 together with the capacitor element 1, and then a horizontal throttle groove 4a is formed in the metal case 4, and the opening edge 4b of the case is turned inward. It is caulked so that it curls.

In this case, the horizontal throttle groove 4a is formed by the rubber elastic body 11.
Because it is formed at a position corresponding to the circumferential surface of the fluororesin body 1
There is no need to perform any processing on 2a and 12b.

Furthermore, as the lateral throttle groove 4a is formed, the rubber elastic body 11 is compressed toward its center, and as a reaction to this, it tends to expand in the axial direction (vertical direction), but the fluororesin body 1
Since the bulge is suppressed by 2a and 12b, the airtightness is further improved and no unnecessary mechanical stress is applied to the capacitor element 1.

FIG. 2 shows a second embodiment of the invention. That is, in this second embodiment, in addition to the three-layer laminate of the first embodiment, a rubber elastic body 13 is further provided to form a four-layer laminate.

In this case, the rubber elastic body 13 is the fluororesin body 12b on the side where the opening edge 4b of the metal case 4 is caulked.
According to this, the airtightness of the caulked portion of the opening edge 4b is further improved.

Here, in each of the first embodiment, the second embodiment, the first conventional example shown in FIG. 3, and the second conventional example shown in FIG. 4, the diameter is 5 mm, the axial length is 11 mm, and We prototyped 50 aluminum electrolytic capacitors each with a rating of 25 V and 47 μF using paste of
A high-temperature load test was carried out at 5000 degrees Celsius for 5,000 hours, and the capacitance change rate (ΔC/C), loss angle tangent (tan δ), and leakage current (LC) were measured. Table 1 shows the results.

[0025]

[Table 1] As can be seen from this table, according to the present invention, remarkable effects are seen particularly on the capacitance change rate and the tangent of the loss angle.

[0026]

[Effects of the Invention] As explained above, according to the present invention,
By using a sealing member consisting of a laminate of at least three layers with a rubber elastic body in the middle and fluororesin bodies laminated on both sides, an aluminum electrolytic capacitor with good sealing workability and excellent airtightness is provided.

[Brief explanation of the drawing]

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

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

FIG. 3 is a sectional view showing a first conventional example of an aluminum electrolytic capacitor.

FIG. 4 is a sectional view showing a second conventional example of an aluminum electrolytic capacitor.

[Explanation of symbols]

1 Capacitor element 2 Tab terminal 4 Metal case 4a Horizontal throttle groove 4b Case opening edge 10 Sealing member 11 Rubber elastic body (first sealing element) 12a, 12b Fluorine resin body (second sealing element) 13
Rubber elastic body (third sealing element)

Claims (2)

[Claims] 1. A capacitor element in which an anode foil and a cathode foil made of aluminum are wound with a separator in between, each having a lead terminal attached thereto, and a sealing member attached so as to be inserted through each of the lead terminals. The capacitor element includes a cylindrical metal case with a bottom in which the capacitor element is housed together with the sealing member, and a lateral throttle groove is formed on the circumferential surface of the metal case to engage with the side surface of the sealing member, and In an aluminum electrolytic capacitor in which the opening edge of the metal case is caulked to the member, the sealing member includes a first sealing element made of a rubber elastic body disposed at a position corresponding to the horizontal throttle groove; An aluminum electrolytic capacitor comprising a laminate of at least three layers including a first sealing element and a second sealing element made of a fluororesin body attached to both sides of the first sealing element. 2. A third sealing element made of a rubber elastic body is attached to the second sealing element on the side of the sealing member on which the opening edge of the metal case is caulked. Aluminum electrolytic capacitor.