JPH09129520A - Tantalum solid electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the burning by Joule heating in the shortcircuit time of tantalum solid electrolytic capacitor. SOLUTION: This capacitor is composed of an anode leading wire 2 and a semiconductor layer 4, a carbon layer 5, single or a plurality of cathode conductive layers 6 and a cathode leading out part 7 successively lamination.formed on an anode body 1 whereon a dielectric oxide film 3 is formed. On the other hand, a heat insulating conductive layer 8 is provided between the cathode conductive layers 6 and the cathode leading part 7 or between the cathode conductive layers themselves so that the resistance may be stiffened by the Joule heat generated in the capacitor shortcircuit time thereby enabling the conductive layer 8 to be insulated and the burning to be avoided by the suppressed heating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tantalum solid electrolytic capacitor, and more particularly to a tantalum solid electrolytic capacitor provided with a means for preventing a burnout accident due to Joule heat generation during a short circuit.

[0002]

2. Description of the Related Art As shown in FIGS.
Manganese dioxide layer 4 as a semiconductor, carbon such as graphite, etc. on an anode body 1 having an anode lead wire 2 such as a tantalum wire and having a dielectric oxide film 3 formed on the surface of a sintered body of tantalum powder. When the conventional tantalum solid electrolytic capacitor having a structure in which the layer 5 and one or more cathode conductive layers 6 of silver or copper paste and the cathode lead-out portion 7 are sequentially stacked, Joule heat is generated due to the flowing current, while , The effective surface area of the anode body 1 mainly composed of the tantalum sintered body is much larger than the apparent surface area.
When it exceeds ℃, it burns explosively. For this reason, there is a risk that the tantalum solid electrolytic capacitor is short-circuited and burns out if the amount of heat generated at that time is large, and the circuit board or, in the worst case, the electronic device itself.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the problems of the prior art as described above, and its object is to provide a space between the cathode conductive layer and the cathode lead portion or the cathode conductive layer. An object of the present invention is to provide a highly reliable tantalum solid electrolytic capacitor which can prevent burning damage due to Joule heat generation at the time of short circuit by interposing a conductive layer which is thermally insulated from each other.

[0004]

In order to achieve this object, the present invention provides a semiconductor layer, a carbon layer, and a single layer on an anode body having an anode lead wire and having a dielectric oxide film formed on the surface thereof. Alternatively, in a tantalum solid electrolytic capacitor in which a plurality of cathode conductive layers and a cathode lead portion are sequentially stacked and formed, a conductive material that is thermally insulated between the single cathode conductive layer and the cathode lead portion or between the cathode conductive layers. A layer is provided, and the conductive layer is insulated so that excessive heat generation at the time of a short circuit is suppressed and burnout is prevented.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. 1 and 2. As shown in these drawings, the solid tantalum solid having the conventional structure shown in FIGS. In an electrolytic capacitor, a single cathode conductive layer 6
Between the cathode and the cathode lead-out portion 7 (see FIG. 1) or the cathode conductive layer 6,
There is a configuration in which a conductive layer 8 which is insulated by heat is provided between the 6 (see FIG. 2). Here, the conductive layer 8 which is insulated by heat
Means that the conductivity is maintained as a whole at a temperature lower than 300 ° C., and the material is electrically insulated as a whole at a temperature higher than 300 ° C. Specifically, the softening material such as polyolefin or fluorine-based material is used. Conductive particles such as Pd, Pt, Ag, Cu, Pb, and Sn are provided on the surface of the insulating resin particles, and the conductive material formed is dispersed in a resin such as fluorine-based, epoxy, phenol, or acrylic. Moreover, the conductive layer 8 is formed by means such as solvent drying curing, heat curing, and pressure molding, and at a temperature lower than 300 ° C., the conductive particles of the conductive material come into contact with each other to form a conductive passage, and thus the whole structure is formed. As a result, the conductivity is maintained, and at a high temperature of more than 300 ° C., the insulating resin particles of the conductive material are melted and expanded, so that the contact of the conductive path by the conductive particles is cut off and the whole is insulated. Therefore, when the tantalum solid electrolytic capacitor is short-circuited, the Joule heat generated thereby increases the resistance and insulates the conductive layer 8, suppressing excessive heat generation at the time of short-circuiting and preventing burnout accidents.

[0006]

According to the present invention, therefore, the conductive layer 8 which is insulated by heat is provided between the cathode conductive layer 6 and the cathode lead-out portion 7 or between the cathode conductive layers 6, 6. Therefore, excessive heat generation at the time of short-circuiting of the capacitor is suppressed, and therefore, a burnout accident is prevented and safety and reliability are excellent.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view of an example of a tantalum solid electrolytic capacitor according to the present invention.

FIG. 2 is a vertical cross-sectional view of another example of the tantalum solid electrolytic capacitor according to the present invention.

3 and 4 are vertical sectional views of a conventional tantalum solid electrolytic capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anode body 2 Anode lead wire 3 Dielectric oxide film 4 Semiconductor 5 Carbon layer 6 Cathode conductive layer 7 Cathode derivation part 8 Conductive layer insulated by heat

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hidetoshi Ishizuka 2-44 Muromachi, Hadano City, Kanagawa Prefecture, Fujitsu Towa Electron Limited (72) Inventor Asahi 2-44, Muromachi, Hadano City, Kanagawa Prefecture Towa Electron Limited In the company

Claims (1)

[Claims] 1. A semiconductor layer, a carbon layer, one or a plurality of cathode conductive layers, and a cathode lead portion are sequentially laminated on an anode body having an anode lead wire and having a dielectric oxide film formed on the surface thereof. In the tantalum solid electrolytic capacitor consisting of, a conductive layer which is insulated by heat is provided between the single cathode conductive layer and the cathode lead-out portion or between the cathode conductive layers, and when the short circuit is caused by the insulation of the conductive layer. A tantalum solid electrolytic capacitor having a structure in which excessive heat generation is suppressed and burning is prevented.