JPH04316308A - Manufacture of aluminum electrolytic capacitor - Google Patents

Abstract

PURPOSE:To attach a plug member consisting of the two-layer laminate of fluororesin body and rubber elastic body to a tab terminal with good work efficiency, and get enough airtightness. CONSTITUTION:When attaching a plug member 3 consisting of the two-layer laminate of a fluororesin body 5a and rubber elastic body 5b to a lead terminal 2, the lead insertion hole 3a bored in the fluororesin body 5a is made in a diameter substantially smaller than that of the lead terminal 2, and after enlarging the bore diameter of both lead insertion holes 3a by heating, the plug is set on the lead terminals.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an aluminum electrolytic capacitor, and more particularly to a method of attaching a sealing member to a lead terminal.

0002

2. Description of the Related Art FIG. 2 shows an exploded perspective view of an aluminum electrolytic capacitor as a conventional example. That is,
The electrolytic capacitor includes a capacitor element 1 formed by winding aluminum anode foil and cathode foil with a separator in between.

Prior to winding, tab terminals 2, 2 as lead terminals are attached to each foil. The tab terminal 2 includes a terminal main body 2a that is formed by flattening a part of an aluminum round bar to form a battledore-shaped flat plate portion 2b, and the terminal main body 2a.
It consists of a lead wire 2c welded to the end of a round bar part, and its flat plate part 2b is attached to the foil by caulking or the like. Usually, a CP wire (steel core copper wire) is used for the lead wire 2c.

After the capacitor element 1 is impregnated with a predetermined electrolyte, it is assembled using a sealing member 3. Lead insertion holes 3a, 3a are bored in the enclosure member 3, and the enclosure member 3 is attached to the capacitor element 1 by inserting the tab terminals 2, 2 into the respective holes 3a, 3a.

[0005] Then, the capacitor element 1 is sealed with a sealing member 3.
At the same time, it is housed in a bottomed cylindrical metal case 4. As a result, the opening of the metal case 4 is closed with the sealing member. Thereafter, the metal case 4 is laterally squeezed and the opening edge is caulked.

By the way, when the sealing member 3 is made of a single material such as butyl rubber, the sealing workability including the ability to insert into the tab terminal 2 is good, but it is difficult to handle the electrolyte (paste) which is highly volatile and swellable. However, it is highly permeable and undesirable.

[0007]

SUMMARY OF THE INVENTION Therefore, the sealing member 3 is a two-layer laminate of a fluororesin body 5a and a rubber elastic body 5b. The fluororesin body 5a has sufficient chemical resistance to the electrolytic solution, and is itself highly airtight.

However, there was a problem in the sealing operation when inserting the tab terminal 2. That is, since the fluororesin body 5a is relatively hard, if the diameter of the lead insertion hole 3a is even slightly smaller than that of the tab terminal 2, it becomes difficult to insert the lead through the lead insertion hole 3a.

[0009] Therefore, it is necessary to precisely drill the lead insertion hole 3a so that there is no gap between the lead insertion hole 3a and the tab terminal 2. To solve this problem, it would be possible to make the lead insertion hole 3a slightly larger in diameter and inject a hardening resin liquid to seal the gap after inserting the tab terminal 2, but this would require extra effort. This is unfavorable in terms of productivity.

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 are wound with a separator in between. In addition, a capacitor element is formed by attaching lead terminals to each of the above-mentioned foils, and after inserting a sealing member made of a two-layer laminate of a fluororesin body and a rubber elastic body into each lead terminal, the capacitor element is attached to a capacitor element with a bottom. In a method for manufacturing an aluminum electrolytic capacitor, which is housed in a cylindrical metal case and the opening of the metal case is sealed with the sealing member, the sealing member is attached to the lead terminal when the sealing member is attached to the lead terminal. A lead insertion hole formed in the fluororesin body is made substantially smaller in diameter than the lead terminal, and the diameter of the lead insertion hole is increased by heating, and then the lead insertion hole is inserted into the lead terminal. It's what I did.

[0011] The fluororesin used here is preferably a tetrafluoroethylene resin, and the heating temperature thereof is 100 to 150°C.
is appropriate.

0012

[Operation] When hot air at 125°C is blown onto a fluororesin body that has a lead insertion hole for about 10 seconds, the hole diameter will be reduced by about 20%.
As the lead terminal becomes larger, the lead terminal can be inserted easily.

[0013] After that, when left at room temperature, it tends to return to its original size, so that it comes into close contact with the tab terminal 2, and sufficient airtightness is obtained.

[0014]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to FIG. In addition, only the tab terminal 2 and the sealing member 3 are shown in the figure, and the capacitor element 1, metal case 4, etc. are the same as those in the conventional example described above.
Please refer to FIG. 2 for them.

The sealing member 3 in this embodiment is a two-layer laminate of a fluororesin body 5a and a rubber elastic body 5b, and the sealing member 3 is provided with a pair of lead insertion holes 3a, 3a. Here, the diameter of the lead insertion hole 3a is assumed to be Da.

The tab terminal 2 is made by welding a CP wire 2c to one end of a terminal body 2a having a flat plate portion 2b, and the round bar portion of the terminal body 2a is inserted into the lead insertion hole 3a.

Therefore, if the diameter of the round bar portion of the terminal body 2a is Db, the diameter Da of the lead insertion hole 3a is made substantially smaller than the diameter Db of the round bar portion. That is, Da<Db.

When inserting the tab terminal 2 into the lead insertion hole 3a, the sealing member 3 is exposed to hot air to enlarge the diameter of the lead insertion hole 3a. In this example, the fluororesin body 5a is made of tetrafluoroethylene resin, and the suitable hot air temperature is 100 to 150°C.

If the hole diameter of the lead insertion hole 3a at 25° C. is 1, then the hole diameter when hot air at 125° C. is blown for 10 seconds is approximately 1.2.

Further, if the pressing force required to insert the tab terminal 2 into the lead insertion hole 3a at 25° C. is 1, then 1
The pressing force after blowing hot air at 25°C for 10 seconds is approximately 0.
2 is enough.

After the tab terminal 2 is inserted, the fluororesin body 5a shrinks to its original size by natural cooling or forced cooling, so the lead insertion hole 3a comes into close contact with the tab terminal 2, and sufficient airtightness is achieved. can get. Further, since the round bar portion of the terminal body 2a is reinforced with the fluororesin body 5a, the bending strength of the tab terminal 2 is increased.

[0022]

[Effects of the Invention] As explained above, according to the present invention,
A sealing member made of a two-layer laminate of a fluororesin body and a rubber elastic body can be attached to a tab terminal with good workability, and sufficient airtightness can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a tab terminal and a half cross section of a sealing member inserted therein, according to an embodiment of the present invention;

FIG. 2 is an exploded perspective view showing a conventional aluminum electrolytic capacitor.

[Explanation of symbols]

1 Capacitor element 2 Tab terminal 2a Terminal body 2b Flat plate part 2c Lead wire 3 Sealing member 3a Lead insertion hole 4 Metal case 5a Fluororesin body 5b Rubber elastic body

Claims (2)

[Claims] 1. A capacitor element comprising an anode foil and a cathode foil made of aluminum wound with a separator interposed therebetween, and lead terminals attached to each of the foils, each of which has a fluororesin body and a rubber After a sealing member made of a two-layer laminate of elastic bodies is inserted, the capacitor element is housed in a bottomed cylindrical metal case, and the opening of the metal case is sealed with the sealing member. In the method for manufacturing an electrolytic capacitor, when attaching the sealing member to the lead terminal, a lead insertion hole formed in the fluororesin body constituting the sealing member has a diameter substantially smaller than the diameter of the lead terminal; A method for manufacturing an aluminum electrolytic capacitor, comprising increasing the diameter of the lead insertion hole by heating and then inserting the lead into the lead terminal. 2. The fluororesin body is made of tetrafluoroethylene resin, and the heating temperature thereof is 100 to 150°C.
The method for manufacturing an aluminum electrolytic capacitor described in .