JPS5934121Y2 - Electrolytic capacitor - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electrolytic capacitor using a metal having a valve action (hereinafter abbreviated as valve action metal) such as tantalum or niobium.

In general, a solid electrolytic capacitor is made of a valve metal, and an oxide film as a dielectric, a semiconductor layer as an electrolyte, and a conductive layer as a cathode are sequentially formed on a sintered anode provided with a rod-shaped body made of the same metal. The capacitor element is composed of external leads connected to the rod-shaped body and the cathode, and a resin insulator surrounding the capacitor element.

However, when creating an oxide film that serves as a dielectric, generally the lead connected to the rod-shaped body of the sintered anode is connected to a band-shaped metal plate, and the sintered anode is suspended to form the oxide film. The lead wires are immersed in an anodic chemical solution such as a phosphoric acid solution to undergo chemical conversion, but at this time the chemical liquid creeps up to the roots of the leads, which may corrode the lead wires or cause damage to semiconductors made of manganese dioxide. There were problems such as short circuits caused by the layers climbing up.

An object of the present invention is to provide an electrolytic capacitor that solves this difficulty.

In the electrolytic capacitor according to the present invention, the outer bottom surface of a container-like body made of a valve-action metal or the tip of a cone-shaped body is welded to the anode body made of a valve-action metal, and It is characterized by a lead that has good solderability and is fixed to the bottom of the body by welding.

Next, one embodiment of the present invention will be described with reference to FIGS. 1 and 2.

As shown in Fig. 1, first, a sintered anode 1 is made by pressing and sintering tantalum powder, and a lead wire 2 made of nickel or the like with good solder is welded to the inner surface of the valve metal body in the form of a bowl-shaped container made of tantalum. Weld 3.

This structure is immersed in a phosphoric acid solution as deeply as possible to form the electrolytic oxide film 7 in a conventional manner, without allowing the container-shaped valve metal body 3 to sink to the liquid surface. It is immersed in a manganese nitrate solution for forming a semiconductor layer to form a manganese dioxide layer.

At this time, the sintered body anode 1 is immersed in a manganese nitrate solution to a position above the upper surface and below the level of the chemical conversion liquid and thermally decomposed to form a manganese dioxide semiconductor layer, and then a graphite layer,
A silver paste conductive layer is formed as a cathode layer 5, and a cathode lead 4 is provided.

Next, a resin sheath 6 was applied and the completed container is shown in Fig. 2.

The container manufactured in this way prevents each solution from creeping up to the lead wire side due to the container-shaped valve metal body 3, and can be easily connected to the anode body, eliminating the above-mentioned drawbacks. It has the advantage of stable production.

Note that the shape of the valve metal body 3 is not limited to one with a recess on the inside; as shown in FIG. A similar effect can be obtained by using

Furthermore, the valve metal body 3 may have an inverted conical shape, as shown in FIG. 4, and is not particularly limited.

[Brief explanation of the drawing]

FIGS. 1 and 2 are vertical cross-sectional views sequentially showing an electrolytic capacitor according to an embodiment of the present invention along the manufacturing process. 3 and 4 are sectional views showing other embodiments of the present invention, respectively. Codes in the diagram 1... Electrode body, 2, 4...
・Lead with good solderability, 3... Umbrella-shaped body made of anodic oxide film forming metal, 7... Dielectric material, 5...
... Cathode layer, 6 ... Resin exterior.

Claims (1)

[Scope of utility model registration request] In an electrolytic capacitor in which an anode lead is connected to an anode body made of a metal having a valve action, the one end of the valve metal body having a conical outer shape whose total outer diameter increases from one end to the other end is connected to the anode body. An electrolytic capacitor characterized in that the anode lead is connected to the inner surface of the outer diameter of the other end of the valve metal body.