JPS6023962Y2 - solid electrolytic capacitor - Google Patents

Description

[Detailed explanation of the idea] This proposal concerns the improvement of solid electrolytic capacitors.

In general, this type of solid electrolytic capacitor is made of a capacitor element A made by press-molding metal powder having a valve action such as tantalum, niobium, aluminum, etc. into a cylindrical shape and sintering it, as shown in FIG. 1. A functional metal wire is planted as an anode lead B, a first external lead member C is welded to the protruding part of this anode lead B, and a second external lead member is oxidized on the circumferential surface of the capacitor element A. The half member F is used to connect to the electrode lead layer E formed through the layer, the semiconductor layer, and the graphite layer, and then,
The entire circumferential surface of the capacitor element A is covered with a resin material G.

By the way, the electrode lead layer E in the capacitor element A is formed by dip-coating a conductive material made of silver powder, resin, or solvent onto a graphite layer and then drying it. In order to ensure good soldering with the components, the proportion of silver powder in the total amount is set to approximately 7%.

However, recently the prices of precious metals including silver have soared abnormally, and the impact of this on the cost of capacitors cannot be ignored.

Therefore, if it is possible to extract an electrode from the graphite layer as a cathode layer without using a conductive member containing such a noble metal, it is desirable not only to effectively reduce the cost of the capacitor but also to save precious resources. .

In view of these points, the present proposal provides a solid electrolytic capacitor with a simple configuration that allows electrodes to be drawn out from the graphite layer without using a conductive member containing noble metal powder.Examples will be described below. do.

In FIG. 2, numeral 1 denotes a capacitor element made of a metal member having a valve action. , a graphite layer 2 is formed on the peripheral surface thereof with an oxide layer and a semiconductor layer interposed therebetween.

Reference numeral 3 denotes an anode lead made of a metal wire having a valve action and led out from the capacitor element 1; However, it can also be welded around the capacitor element 1.

Reference numeral 4 denotes a first external lead member configured in an L-shape, for example, and its bent portion 4a is connected to the protruding portion 3a of the anode lead 3.
It is welded across the

5 is, for example, a metal case configured in a cylindrical shape with a bottom,
A capacitor element 1 is housed inside.

A solder member 6 is interposed between the graphite layer 2 of the capacitor element 1 and the metal case 5,
Each is electrically connected.

Reference numeral 7 denotes a second external lead member configured, for example, in the shape of a strainer, one end of which is welded to the wall surface of the metal case 5.

Note that this second external lead member 7 can also be connected to the solder member 6 and led out.

Reference numeral 8 denotes a resin material that coats the entire circumferential surface of the metal case 5, and can be coated by a dipping method or the like in addition to a molding method.

Next, a method of assembling this solid electrolytic capacitor will be explained with reference to FIG.

First, as shown in FIG. 1A, the first external lead member 4 is welded to the anode lead 3 led out from the capacitor element 1 so that the bent portion 4a intersects with the protruding portion 3a of the first external lead member 4.

Then, a graphite layer 2 is formed on the circumferential surface of the capacitor element 1 via an oxide layer and a semiconductor layer.

Next, as shown in the figure, the capacitor element 1 is positioned above the opening of the metal case 5.

Then, the metal case 5 is heated, and a required amount of solder member 6 is supplied inside to melt it.

Note that the second external lead member 7 is in contact with the metal case 5 in advance.

Next, as shown in FIG.
be interposed between.

In this state, although the solder member 6 is not compatible with the graphite layer 2, it is electrically connected to the metal case 5 by mechanical contact.

After that, the metal case 5 is cooled, and its outer peripheral surface is coated with a resin material 8.
The solid electrolytic capacitor shown in FIG. 2 is obtained by coating with the following.

In this way, the capacitor element 1 is housed in the metal case 5, and since the solder member 6 is interposed between the graphite layer 2 and the metal case 5, the electrodes can be drawn out from the graphite layer 2 using noble metal powder as a main component. This can be reliably carried out without any intervening electrode extraction layer.

Therefore, the cost of the capacitor can be effectively reduced.

Furthermore, since the solder member is not compatible with the graphite layer at all, it is impossible to connect the second external lead member by the dipping method.
The solder member 6 is stored in the metal case 5, and the solder member 6 is brought into mechanical contact with the graphite layer 2 by storing the capacitor element 1 in the metal case 5.
The electrical connection between the metal case 5 and the metal case 5 can be reliably established.

Moreover, since the entire circumferential surface of the metal case 5 is strongly covered with the resin material 8, even if the electrical connection between the graphite layer 2 and the solder member 6 is made by mere mechanical contact, each Not only can displacement be completely prevented, but also good electrical connection can be achieved over a long period of time.

In this regard, according to experiments conducted by the inventor of the present invention, no deterioration in characteristics that would be a problem in practical use was observed even after 1000 Ctf was passed in a running test.

In particular, if the outer surface of the metal case 5 is made to be easily oxidized, the adhesion between the metal case 5 and the resin material 8 can be further improved when the metal case 5 is covered with the resin material 8, and the above-mentioned effects can also be further improved.

In the present invention, the capacitor element may be formed by press-molding metal powder into a desired shape, or may also be formed using a wire or a plate material.

Further, the external lead member can be led out in the same direction or in the opposite direction.

As described above, according to the present invention, it is possible to completely omit the electrode extraction layer whose main component is noble metal powder due to the simple structure, and the cost of the capacitor can be effectively reduced.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a conventional example, FIG. 2 is a side sectional view showing an embodiment of the present invention, and FIG. 3 is a side sectional view for explaining an assembly method. In the figure, 1 is a capacitor element, 2 is a graphite layer, 4 is a first external lead member, 5 is a metal case, 6 is a solder member, 7 is a second external lead member, and 8 is a resin material.

Claims (1)

[Scope of utility model registration request] A capacitor element made of a metal member having a valve action and having a graphite layer formed on its surface through an oxide layer and a semiconductor layer, a metal case housing the capacitor element, and a metal case and a graphite layer of the capacitor element. A solder member located between and electrically connected to each other, a first external lead member led out from the capacitor element, a second external lead member led out from the metal case or the solder member, and the entire part of the metal case. A solid electrolytic capacitor characterized by comprising a resin material covering a peripheral surface.