JPS5824434Y2 - 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 has an anode lead extending from a capacitor element made by press-molding and sintering metal powder with valve action, such as tantalum, niobium, or aluminum, into a cylindrical shape, as shown in Figure 1. A first external lead member C is welded to B, and this capacitor element A is housed in a bottomed metal cylindrical case D, and an electrode extraction layer E is formed on the circumferential surface of capacitor element A.
is electrically connected to the conductive adhesive F that has been injected into the case D in advance, and the opening of the case D is closed with the resin material G, and the second external lead member H is inserted from the bottom outer surface of the case D.
It is constructed by deriving the

However, prior to 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 an impregnation-pyrolysis operation of 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 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 pull-out layer E gets caught on the open end of the case D and receives the pressing force, causing cracks in the oxide layer, and sometimes the electrode pull-out layer E peels off. This has the disadvantage that the oxide layer and the semiconductor layer are damaged by the capacitor, or the oxide layer and the semiconductor layer are damaged by the pressing force from the inner wall of the case D during storage, resulting in a significant deterioration of the capacitor characteristics.

This project was proposed in view of these points, and consists of a capacitor element that uses a metal member that has a valve action as a material and has an electrode extraction layer formed on its circumferential surface, and a metal member that has a valve action that is derived from the capacitor element. The present invention comprises an anode lead made of This is characterized in that the electrode lead layer of the capacitor element and the anode lead are electrically connected.

An embodiment of the present invention will be described with reference to FIG. 2. 1 is a capacitor element formed of a metal member having a valve action as a material, and the illustrated example is a capacitor element formed by pressure forming 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 curved surface of the capacitor element 1 to form a conductor.

Reference numeral 3 denotes an electrode lead layer formed on the circumferential surface of the capacitor element 1 via an oxide layer and a semiconductor layer, and 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 made of only one conductive material or other conductive members.

Reference numeral 4 denotes a bottomed cylindrical first case made of a metal member, which is attached to the capacitor element 1 from the outlet side of the anode lead 2.

5 is the solder injected into the bottom inner surface of the first case 4;

The ends of the protrusion 2a of the anode lead 2 are connected with a conductive adhesive such as silver paste.

Reference numeral 6 denotes a first external lead member led out from the bottom outer surface of the first case 4.

Reference numeral 7 denotes a bottomed cylindrical second case made of a metal member, which is attached to the capacitor element 1 from the side from which the anode lead 2 is not led out.

Note that it is slightly spaced apart from the open end of the first case 4.

8 is a conductive adhesive such as solder or silver paste injected into the bottom inner surface of the second case 7, and is electrically connected to the electrode lead layer 3.

Reference numeral 9 denotes a second external lead member led out from the bottom outer surface of the second case 7, and led out, for example, in the opposite direction to the first external lead member 6.

Reference numeral 10 denotes a resin material injected into the openings of the first and second cases 4 and 7.

In this way, since the first and second cases 4 and 7 are attached to the capacitor element 1 from the lead-out side and the non-lead-out side of the anode lead 2, there is no possibility that the capacitor element 1 will be exposed to the capacitor element 1 from the inner wall of the case when the case is attached. The pressing force can be alleviated.

Therefore, damage to the oxide layer and semiconductor layer can be alleviated, and capacitor characteristics, particularly leakage current characteristics, can be significantly improved.

Further, the end of the protrusion 2a of the anode lead 2 is coated with a conductive adhesive 5.
Since the capacitor element 1 is electrically connected to the first case 4 through the capacitor element 1, sparks generated when welding the first external lead member to the anode lead as in the conventional case may damage the anode lead lead-out side of the capacitor element 1. There is no damage to the oxide layer or semiconductor layer in the capacitor, and the capacitor characteristics can be improved in this respect as well.

Furthermore, the first. Since the openings of the second cases 4 and 7 are closed by injecting the resin material 10, the airtightness inside the cases can be improved.

For this reason, moisture resistance can be improved.

In the present invention, the first external lead member 6 may be substituted by forming a small hole in the bottom of the first case 4 and extending the anode lead 2 through the small hole.

As described above, according to the present invention, by dividing the case into two parts, it is possible to reduce the pressure exerted by the case on the oxide layer and the semiconductor layer when the case is attached to the capacitor element.
This allows the capacitor characteristics to be significantly improved.

[Brief explanation of drawings]

FIGS. 1 and 2 are front sectional views showing an embodiment of the conventional and the present invention. 1... Capacitor element, 2...
Anode lead, 3... Electrode lead layer, 4, 7...
...Case, 10...Resin material.

Claims (1)

[Scope of utility model registration request] A capacitor element made of a metal member with a valve action as a material and with an electrode lead layer formed on its circumferential surface, an anode lead made of a metal member with a valve action derived from the capacitor element, and an anode lead of the capacitor element. It is equipped with a bottomed cylindrical case attached from the lead-out side and the non-lead side, and a resin material injected into the opening of each case, and the electrode lead-out layer and anode lead of the capacitor element are electrically connected to the case. A solid electrolytic capacitor characterized by being connected.