JPS5833692B2 - Manufacturing method of solid electrolytic capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for manufacturing a solid electrolytic capacitor.

Generally, this kind of capacitor has a valve action in the capacitor pellet A, which is made by press-molding metal powder such as tankle, niobium, aluminum, etc., into a cylindrical shape and sintering it, as shown in Fig. 1. A metal wire is planted as an anode lead B, a first external lead wire C is welded to this anode lead B, and a second external lead wire is attached to the circumferential surface of the capacitor pellet A through an oxide layer and a semiconductor layer. The capacitor pellet A is connected to the formed electrode extraction layer, and then the entire circumferential surface of the capacitor pellet A is coated with a resin material E and taken over.

Incidentally, the anode lead B is integrated into the capacitor pellet A by applying pressure with upper and lower punches while planted in the metal powder forming the capacitor pellet A. However, due to the structure of the punch, the anode lead The compressed density of the metal powder in the peripheral portion of the lead B is smaller than that in the peripheral portion of the pellet, and the mechanical strength also tends to be weaker accordingly.

Therefore, when a pressing force is applied to the capacitor pellet A, especially after the chemical formation process, cracks occur at the connection boundary between the anode lead B and the metal powder of the capacitor pellet, and the anode lead B sometimes comes out from the capacitor pellet A. Sometimes it happens.

For this reason, the oxide layer formed at the boundary portion is destroyed, causing a short circuit between the anode and the cathode, or causing a significant increase in leakage current.

In view of these points, the present invention provides a solid electrolyte that can significantly reduce damage to the oxide layer formed at the connection boundary between the anode lead and the metal powder even if pressing force is applied to the capacitor pellet after the chemical formation process. This invention provides a method for manufacturing a capacitor, and the manufacturing method will be described below with reference to FIG.

First, an anode lead 2 made of a metal wire having a valve action is planted in advance on a capacitor pellet 1 made by press-molding and sintering a metal powder having a valve action, such as tankle, niobium, or aluminum, into a cylindrical shape. .

Next, a notch 3 is formed at the root portion of the anode lead 2 protruding from the capacitor pellet 1, and the diameter of the anode lead 2 is locally reduced.

Note that this notch 3 is a gather blade having a V-shaped recess that moves back and forth to adjust the position from the left and right sides of the anode grid 2, for example, in the process of fixing capacitor pellets 1 to a metal plate at regular pitch intervals. It is desirable to form the position at the same time as the position correction.

Next, after sequentially forming an oxide layer, a semiconductor layer, and an electrode lead layer on the surface of the capacitor pellet 1 by a chemical conversion operation, a first external lead wire 4 bent into an L shape, for example, is attached to the anode lead portion above the notch 3. to weld.

Then, the lower end of the second external lead wire 5 is soldered to the electrode lead layer of the capacitor pellet 1.

Thereafter, the entire circumferential surface of the capacitor pellet 1 is molded with a resin material 6 to obtain a solid electrolytic capacitor.

In addition, for the exterior of the capacitor pellet 1, a metal case or a resin case can be used in addition to the resin material.

Since the notch 3 is formed in the protruding portion of the anode lead 2 before the chemical formation process, even if a pressing force is applied to the capacitor pellet 1 after the chemical formation process, the capacitor pellet 1 will deform around the notch 3. It rotates to relieve the pressing force.

Therefore, damage to the oxide layer formed at the connection boundary between the anode lead 2 and the metal powder can be significantly reduced, and leakage current characteristics can be improved.

Furthermore, even if the axes of the upper portion of the anode lead 2 and the capacitor pellet 1 become misaligned due to the action of the pressing force, this can be easily corrected by applying a pressing force in the opposite direction to the capacitor pellet 1.

Moreover, since this correction does not cause the oxide layer at the connection boundary between the anode IJ-de 2 and the metal powder to be tJ4, the number of position correction operations of the capacitor pellet 1 is increased during the process, and the first and second Connection work for external lead wires can be improved.

Furthermore, even if the capacitor pellet 1 is eccentric after welding the first external lead wire 4 to the anode lead 2, it can be easily corrected by the above-described operation without damaging the oxide layer.

Furthermore, if the notch 3 is formed at the same time as the position of the capacitor pellet 1 is adjusted, work efficiency can be further improved.

In the present invention, the shape of the notch is not particularly limited as long as a portion of locally weak mechanical strength can be formed in the anode IJ-de.

Further, the capacitor pellet can be formed without applying pressure or sintering if necessary.

As described above, according to the present invention, it is possible to effectively suppress characteristic deterioration caused by pressing force acting on the capacitor pellet during the manufacturing process.

[Brief explanation of drawings]

FIG. 1 is a front sectional view of a conventional capacitor, and FIG. 2 is a front sectional view of a capacitor according to the present invention.

Claims (1)

[Claims] 1. A step of forming a notch in an anode lead extending from a capacitor pellet made by molding metal powder with valve action into a desired shape, and then a step of sequentially forming an oxide layer, a semiconductor layer, and an electrode lead layer on the capacitor pellet. And then,
1. A method for manufacturing a solid electrolytic capacitor, comprising the step of welding an external lead wire to an anode lead such that the notch is located between the capacitor pellet and the external lead wire.