JPS5824433Y2 - Cotai Denkai Capacitor - Google Patents

Description

[Detailed Description of the Invention] The present invention mainly relates to the improvement of a small solid electrolytic capacitor.

In general, this type of solid electrolytic capacitor is made by press-molding metal powder having a valve action such as tantalum, niobium, or aluminum into a cylindrical shape and sintering it as shown in Figure 1. A first external lead member C is welded to the extending anode lead B, and this capacitor element A is housed in a metal bottomed cylindrical case D, and an electrode lead-out layer E is formed on the circumferential surface of the capacitor element A. is electrically connected to a conductive adhesive F such as solder that has been injected into the case D in advance, and the opening of the case D is closed with a resin material G, and a second external lead member is inserted from the bottom outer surface of the case D. It is constructed by deriving H.

By the way, before forming the electrode extension layer E on the circumferential surface of the capacitor element A, an oxide layer is formed as a dielectric layer by chemical conversion treatment, and an oxide layer is formed on this oxide layer by impregnation and thermal decomposition of a semiconductor mother liquor. Although a semiconductor layer is formed, these oxide layers and semiconductor layers tend to be easily damaged by mechanical stress or the like.

Therefore, if the case D is extremely small, for example, with an inner diameter of 2 to 3 mm or less and a total length of 5 mm or less, the outer diameter of the capacitor A should be relatively close to the case inner diameter due to capacitance. Because of this, especially by forming the semiconductor white layer and the electrode extraction layer E, the outer diameter thereof becomes further larger, and the allowance for the inner diameter of the case D decreases.

For this reason, when the capacitor element A is housed in the case D, the electrode extension layer E gets caught on the open end of the case D and receives a pressing force, and sometimes the electrode extension layer peels off, causing an oxide layer and a semiconductor. The disadvantage is that the layers are damaged and the capacitor properties are significantly degraded.

This project was proposed in view of these points, and includes a capacitor element that uses a metal member with valve action as its material and has an electrode lead layer formed on its circumferential surface, and a first external lead led out from the capacitor element. a resin material applied to cover almost the entire surface of the lead-out side of the first external lead member of the capacitor element; and a resin material formed on the resin material so as not to contact the first external lead member. a first metal layer having good adhesion to the resin material;
a second external lead member led out from the electrode extraction layer;
It is characterized by comprising an electrode lead layer of a capacitor element and a second metal layer such as solder formed on the first metal layer.

An embodiment of the present invention will be explained with reference to FIG. 2. Reference numeral 1 indicates a condenser element made of a metal member having a valve action, and the illustrated example is made by press-molding metal powder having a valve action into a cylindrical shape. Constructed by sintering.

Incidentally, as the metal member, a metal wire or a crushed metal wire may also be used.

Reference numeral 2 denotes an anode lead made of a metal member having a valve function and installed in advance on the capacitor element 1, and can also be welded to the circumferential surface of the capacitor element 1 to lead out.

Reference numeral 3 denotes an electrode lead layer formed on the circumferential surface of the condenser element 1 through an oxide layer and a semiconductor layer. In the illustrated example, it is composed of a graphite layer and a silver paste layer deposited in this order, but it is simply a graphite layer. It can also be constructed by using only a single conductive member or by using other conductive members.

4 is a first external lead member bent into an L shape, for example;
It is welded across the protrusion 2a of the anode lead 2.

Reference numeral 5 denotes a resin material applied so as to cover almost the entire surface of the lead-out side of the anode lead 2 of the capacitor element 1,
In particular, the connection portion between the anode lead 2 and the first external lead member 4 is completely hidden.

Reference numeral 6 denotes a first metal layer formed on the surface of the resin material 5 excluding the lead-out portion of the first external lead member 4. For example, a metal material (such as silver paste) that can be soldered is applied by dip coating or electroless plating. , thermal spraying, vapor deposition, etc.

In particular, as the first metal layer 6, silver paste containing silver powder and resin is suitable.

Reference numeral 7 denotes a second external lead member, which is led out from the bottom of the electrode extraction layer 3, and is led out from the side of the first external lead member 4.
It can also be derived in the same direction.

A second metal layer 8 is densely formed on the electrode lead layer 3 of the capacitor element 1 and the first metal layer 6 of the resin material 5, and is formed by dipping the capacitor element 1 in a molten solder layer. Although this is preferable from the viewpoint of workability, other metal members may also be deposited by thermal spraying or the like.

In this way, a second
Since the metal layer 8 is densely formed, sufficient moisture resistance can be obtained as in the conventional metal case.

In particular, since the second metal layer 8 is present at the boundary between the capacitor element 1 and the resin material 5, the moisture resistance does not deteriorate at all from this boundary.

In addition, by adopting the metal layer 8, the metal case can be completely omitted, which not only completely solves the problems that occur when conventional capacitor elements are housed in the metal case, but also improves workability and reduces costs. be able to.

Moreover, when forming the second metal layer 8, it is difficult for mechanical stress to act on the oxide layer and the semiconductor layer through the electrode lead layer 3, so damage to the oxide layer and the semiconductor layer is reduced.
Therefore, leakage current characteristics etc. can be improved.

Moreover, when the second metal layer 8 is deposited on the resin material 5, since the first metal layer 6 is formed on the resin material 5 in advance, the second metal layer 8 is deposited on the resin material 5.
The adhesion of the metal layer 8 to the first metal layer 6 is improved, which is advantageous in terms of moisture resistance.

In the present invention, the first external lead member 4 can also be substituted by extending the anode lead 2.

Further, the anode lead 2 can be planted on the capacitor element 1 or can be welded to the circumferential surface.

Furthermore, if a higher degree of moisture resistance is required, the second metal layer 8 may be coated with a resin material.

As described above, according to the present invention, the outer circumferential surface of the capacitor element and the resin material is the first. By appropriately covering with a second metal layer, the metal case can be completely omitted.
It is possible to solve the problems that occur when using a metal case, and together with improved workability, it is possible to reduce capacitor costs.

[Brief explanation of drawings]

FIGS. 1 and 2 are front sectional views showing an embodiment of the conventional and the present invention. 1...condenser element, 4, 2...
...First external lead member, 3... Electrode extraction layer, 5... Resin material, 6... First metal layer, 7... - Second external lead member, 8...
...Second metal layer.

Claims (1)

[Scope of utility model registration request] A capacitor element made of a metal member having a valve action as a material and having an electrode lead-out layer formed on its peripheral surface, a first external lead member led out from the capacitor element, and a lead-out side of the first external lead member of the capacitor element. a first metal layer that has good adhesion to the resin material and is formed on the resin material so as not to contact the first external lead member; , the second external lead member led out from the electrode lead layer, the electrode lead layer of the capacitor element and the first
A solid electrolytic capacitor comprising a second metal layer such as solder formed on the metal layer.