JPS5832260Y2 - solid electrolytic capacitor - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a solid electrolytic capacitor, and more specifically,
This invention relates to a solid electrolytic capacitor with an improved lead structure.

As solid electrolytic capacitors, for example, a metal case resin-filled solid electrolytic capacitor shown in FIG. 1 and a resin paint-dipped solid electrolytic capacitor shown in FIG. 2 are already known.

The solid electrolytic capacitor shown in FIG. 1 has an internal anode lead wire 2 made of, for example, tantalum, from one end 1a of a valve metal element 1 made of a sintered body of tantalum, aluminum, titanium, niobium, tungsten, columbium, hafnium, zircon, etc. In other words, a part of the lead wire 2 is embedded in the valve metal element 1, and using this internal anode lead wire 2,
An anodic oxide film 3 is formed on the surface of the valve metal element 1, and further,
For example, a semiconductor metal oxide layer 4 made of manganese dioxide is formed, and a cathode layer 5 made of a graphite layer and a cathode metal layer such as silver is formed, and a metal case 7 is fixed to this cathode layer 5 with solder 6. Then, an external anode lead wire 8 is fixed to the internal anode lead wire 2 by welding or the like, a synthetic resin insulator 9 is injected into the metal case 7, an insulation coating 10 is provided on the outer peripheral surface of the metal case 7, and the metal case The cathode lead wire 11 and the external anode lead wire 8 welded to the external anode lead wire 7 are configured to electrically connect to an external circuit.

Note that 12 is an insulating layer that separates the anode and cathode.

By forming a solid electrolytic capacitor in this manner, the external dimensions can be made constant.

However, the internal anode lead wire 8, which had been corroded by the process for forming the capacitor, had to be cut and a new external anode lead wire 8 connected, and a metal case was used to mechanically protect this joint. Since the metal case 7 has to be formed so as to cover the joint portion, the metal case 7 and the entire element inevitably become long.

Another disadvantage is that as the device becomes smaller, it becomes difficult to fit the insulator 9 into the metal case 7.

Furthermore, the insulating coating 10 must be provided on the surface of the metal case 7, which has the disadvantage of increasing costs.

The resin paint dip type solid electrolytic capacitor shown in Fig. 2 has a cathode lead directly connected to the solder 6 on the cathode layer 5 without using a metal case in order to eliminate the drawbacks of the metal case resin-filled capacitor described above. Glue the wire 11 and form the exterior insulation layer 1.
3.

This configuration is more advantageous than a metal case type in terms of cost.

However, there is a drawback that the external dimensions are not constant, which is inconvenient when automatically mounting the device on a printed circuit board or the like.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a solid electrolytic capacitor that can suppress an increase in the cost of a capacitor element and keep its external dimensions substantially constant.

To achieve the above object, the present invention includes a cylindrical or prismatic valve metal element, an internal anode lead wire led out from one end of the valve metal element, and an anodized film formed on the valve metal element. , a semiconductor metal oxide layer formed on the anodic oxide film, a cathode layer formed on the semiconductor metal oxide layer, a cathode metal cap fixed to the cathode layer, and a cathode metal cap fixed to the cathode metal cap. a metal plate having external dimensions substantially equal to the external dimensions of the bottom of the metal cap, disposed coaxially with respect to the metal cap, and to which the internal anode lead wire is coupled; This relates to a solid electrolytic capacitor in which an external anode lead wire led out from a metal plate and an exterior insulating layer coated so that at least a portion of the cathode lead wire and the external anode lead wire are kept uncovered. be.

According to the present invention, a metal plate is disposed on the anode side, an internal anode lead wire is connected thereto, and the metal plate has approximately the same external dimensions as the bottom of the cathode metal cap, so it is constructed in a dip type. Even if it is, it does not become extremely oval or elliptical, but becomes cylindrical or prismatic, and in particular, it is possible to make the dimensions of both shoulders substantially constant.

Therefore, automatic attachment to a printed circuit board or the like using both shoulders of the element becomes easy.

In addition, it is possible to reduce costs compared to a metal case resin-filled capacitor.

An embodiment of the present invention will be described below with reference to FIGS. 3 and 4.

However, in FIGS. 3 and 4, the numbers 1 to 6, 8, and 11 to 13 are substantially the same as those with the same numbers in FIGS. 1 and 2, so The explanation will be omitted.

In the resin paint dip type solid electrolytic capacitor according to the present invention shown in FIGS. 3 and 4, a metal cap 14 is used instead of a metal case.

As is clear from FIG. 3, the metal cap 14 is not formed to include a joint between the internal anode lead wire 2 and the external anode lead wire 8, but is formed by applying solder 6 or a conductive adhesive to the cathode layer 5. It is formed so that it can be overturned through the

A disc-shaped metal plate 15 is fixed or integrally formed on the external anode lead wire 8 in advance, and the internal anode lead wire 2 is attached to the metal plate 15 before the exterior insulating layer 13 made of resin paint is provided.
is welded.

Note that the diameter of the metal plate 15 is approximately equal to the diameter of the bottom portion 14a of the metal cap 14.

The inner anode lead wire 2 is fixed to a metal plate 15 integrated with the outer anode lead wire 8, and the metal cap 14 is fixed to the cathode layer 5 via solder 6 or a conductive adhesive, and then dipped in resin paint. For example, as shown in FIG.
is formed and an electrically insulating coating and mechanical protection are achieved.

As is clear from the above, in the solid electrolytic capacitor of this embodiment, a metal plate 15 having approximately the same external dimensions as the bottom portion 14a of the metal cap 14 is arranged on the anode side, and this metal plate 15 is arranged coaxially with the metal cap 14. Since the exterior insulating layer 13 is provided while maintaining the valve metal terminal 1 in this state, that is, in a state facing the one end 1a of the valve metal terminal 1, it is possible to make the left shoulder portion 16 and the right shoulder portion 17 of the capacitor element substantially coincident in external dimensions. It becomes possible,
It becomes possible to make the element as a whole cylindrical.

Therefore, it becomes an element convenient for use in automatic mounting devices and the like.

Furthermore, since the structure is such that the internal anode lead wire 2 is not directly connected to the external anode lead wire 8 but is connected to the metal plate 15, the joining operation becomes easy and it is also possible to further increase the joint strength. .

Further, the degree of freedom in selecting the material of the external anode lead wire 8 is increased.

In addition, since the metal cap 14 is used instead of a metal case, not only is it possible to reduce costs by saving materials, but there is no need to inject resin into the metal case, and manufacturing becomes easier.

Further, it becomes easy to arrange the external anode lead wire 8 and the cathode lead wire 11 coaxially.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment and can be further modified.

For example, as shown in FIG. 5, a recess 18 for connecting the internal anode lead wire 2 may be provided in the metal plate 15.

Further, the metal plate 15 and the internal anode lead wire 2 may be coupled by caulking, or may be coupled by another method.

Further, the metal plate 15 may be integrally formed with the external anode lead wire 8.

Further, the valve metal element 1 may be made into a prismatic shape instead of a cylindrical shape, and the cap 14 and the metal plate 15 may also be made into a prismatic shape.

Further, instead of using the valve metal element 1 as a sintered body, the valve metal element 1 may be made of a single metal anode body with a porous surface.

[Brief explanation of the drawing]

Fig. 1 is a sectional view illustrating a conventional metal case resin-filled solid electrolytic capacitor, Fig. 2 is a sectional view illustrating a conventional dip type solid electrolytic capacitor, and Fig. 3 is an implementation of the present invention. A sectional view explanatory of a solid electrolytic capacitor according to an example, FIG. 4 is a left side view of the capacitor in FIG.
The figure is a side view showing a modified example of the metal plate. In the symbols used in the drawings, 1 is the valve metal element, 1a is one end, 2 is the internal anode lead wire, 3 is the anodic oxide film, 4 is the semiconductor metal oxide layer, 5 is the cathode layer, and 8 is the cathode layer. An external anode lead wire, 11 a cathode lead wire, 13 an exterior insulation layer,
14 is a metal cap, 14a is a bottom, 15 is a metal plate, 1
6 is the left shoulder, and 17 is the right shoulder.

Claims (1)

[Claims for Utility Model Registration] A cylindrical or prismatic valve metal element, an internal anode lead wire led out from one end of the valve metal element, an anodized film formed on the valve metal element, and an anodized film formed on the valve metal element. a semiconductor metal oxide layer formed on the film; a cathode layer formed on the semiconductor metal oxide layer; a cathode metal cap fixed to the cathode layer; and a cathode fixed to the cathode metal cap. a lead wire; a metal plate having external dimensions substantially equal to the external dimensions of the bottom of the metal cap, disposed coaxially with respect to the metal cap, and to which the internal anode lead wire is coupled; A solid electrolytic capacitor comprising an external anode lead wire led out, and an exterior insulating layer coated so that at least a portion of the cathode lead wire and the external anode lead wire are kept uncovered.