JPS628513A - Solid electrolytic capacitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to solid electrolytic capacitors, and relates to a structure of a conductive carbon layer that improves the moisture resistance and heat resistance characteristics of the impedance of a solid tS capacitor by 1%.

[Conventional technology]

In general, solid objects coated with insulating resin are
As shown in FIG. 4, an anode lead 2 is planted from a metal anode body 1 having a valve action, and an oxide film layer and a semiconductor layer are formed on the circumferential surface of the anode body 1 (a capacitor element (hereinafter referred to as an element) not shown) is formed on the circumferential surface of the anode body 1. Abbreviation) 2. Dip in a suspension consisting of water, a dispersant, a stabilizer, and graphite powder and dry with heat to form a graphite layer 3.Furthermore, a cathode conductor layer 5 consisting of a silver paste layer and a solder layer is formed. After that, attach the anode lead drawer #6't- to the protruding part of the anode lead 2 with the tip bent into an iL shape.
At the same time as welding, the cathode lead wire 7 is soldered to the solder layer of the cathode 4'rlL body layer 5.

The entire circumferential surface of the element is covered with a thermosetting resin material to provide an insulating resin layer 8t, thereby forming a resin-clad solid electrolytic capacitor.

[Problems that the invention helps solve]

However, the conventional graphite layer formed using the above-mentioned conventional graphite suspension has weak adhesion to the semiconductor layer compared to the graphite layer formed only from graphite powder with a particle size of several microns or less, and moreover, Since it is smooth, its adhesion to the silver paste layer is also weak. For this reason, if the circuit board is mounted under thermal stress or exposed to a high temperature and high humidity atmosphere, the adhesion between the semiconductor/ill/graphite layer/silver paste JI1 will decrease due to moisture that has entered the circuit board, increasing impedance. There is.

[Means for solving problems]

An object of the present invention is to provide a solid electrolytic capacitor that eliminates such conventional drawbacks.

According to the present invention, an oxide film layer, a semiconductor layer, and a conductive carbon layer are sequentially formed on an anode body element having a valve metal.

A solid electrolytic capacitor formed by forming a cathode conductor layer, wherein the conductor carbon layer is composed of a water-insoluble resin, a heat-resistant inorganic powder, and a conductor carbon powder. is obtained.

〔Example〕

Hereinafter, the present invention will be explained using a resin-clad tantalum solid electrolytic capacitor with reference to the drawings. FIG. 1 is a longitudinal sectional view of an embodiment of the present invention. In the figure.

11 is an anode body made by vacuum sintering a molded body in which the anode 12 is fully implanted in mental powder and press-molded, this anode body 11
1cm circumferential surface of secondary oxidized skin MP! j, manganese dioxide NJ (
14 is a conductive carbon layer, 23 parts by weight of epoxy resin, 23 parts by weight of phenol-modified epoxy resin, 35 parts by weight of graphite powder, 13 parts by weight of calcium carbonate powder with an average particle size of about 20 microns, hardened A mixture of imidazole and imidazole in a ratio of 6 and 7 parts, thoroughly kneaded, diluted with a solvent, applied to the surface of the element except for the peripheral area of the anode lead 12, and then cured with heat. Reference numeral 15 denotes a cathode conductor layer consisting of a silver paste layer and a solder layer provided by known means;
f! A solder-plated nickel wire is soldered to J15 to provide all cathode lead lead wires 17.

16Fi anode body is planted, and then the anode lead 12 is folded into an L shape and solder-plated nickel wire is welded to create a friend anode lead lead wire, 18 is an insulated resin skin, and anode/cathode lead lead wires 16, A liquid epoxy resin is coated on the surface of the element containing 17t and cured by heat.

Note that the water-insoluble resin is not limited to a mixed resin of epoxy resin and 7-enol-modified epoxy resin, but also includes thermosetting resins such as phenol resin, polyurethane resin, silicone resin, and polyimide resin, cellulose resin, High-temperature plastic resins such as vinyl resins and acrylic resins, and ultraviolet curable resins such as epoxy acrylates and abyroacetal acrylates may be used alone or in combination.

Further, the present invention is characterized in that it is composed of a conductive carbon powder, a water-insoluble resin, and a heat-resistant inorganic powder, and the type, particle size, and shape of the conductive powder are not limited.

Furthermore, as the heat-resistant inorganic powder, carbonates such as iron carbonate and magnesium carbonate, sulfates such as sodium sulfate, glucinates such as calcium phosphate and barium phosphate, and oxides such as alumina, silica, and glass may be used. Of course.

The rated voltage of 10 V during the implementation of this invention exploded in this way.
A heat resistance test was conducted in which 96 tantalum solid electrolytic capacitors with a capacitance of 10 μF were arbitrarily extracted and immersed in a solder bath at a temperature of 280°C for 10 seconds, and in a high temperature and high humidity atmosphere at a temperature of 85°C and a relative humidity of 95%. A moisture resistance test was conducted.

For comparison purposes, conventional construction products were also tested at the same time. Figures 2 and 5 show impedance heat resistance test results, and Figure 3 shows all moisture resistance test results.

It is shown in FIG. It can be seen that the impedance of the conventional product increased by 2 to 4 times after the heat resistance/humidity test, but the impedance of the product of the present invention hardly changed.

[Effects of the Invention] In addition to the above explanation, the non-explosion 8A has the following effects because the conductive carbon layer is composed of a water-insoluble resin, a heat-resistant inorganic powder, and a conductive carbon powder.

(1) Since the water-insoluble resin containing conductive carbon powder and the Manogaf dioxide layer have strong adhesion, an increase in impedance in moisture resistance and heat resistance tests can be suppressed.

(11) Since the heat-resistant inorganic powder with a particle size of several tens of microns protrudes from the surface of the two-conductor carbon layer, the adhesion with the disilver paste layer increases due to the so-called anchor effect, making it difficult to remove solder during the heat resistance test. Increase in impedance and deterioration of impedance due to moisture intrusion (1) can be prevented.

[Brief explanation of drawings]

FIG. 1 is a vertical view of a resin-clad solid electrolytic capacitor according to an embodiment of the present invention. FIG. 2 is an impedance distribution diagram of the solid tS capacitor of the present invention before and after a soldering heat resistance test. FIG. 3 is a diagram showing the impedance and time resistance characteristics of the solid electrolytic container/container of the present invention. Figure 4 is a vertical cross-sectional view of a conventional resin-clad solid electrolytic capacitor. Figure 5 is an impedance distribution diagram of a conventional solid electrolytic capacitor before and after a soldering heat resistance test. FIG. 6 shows a moisture resistance time characteristic diagram of impedance of a conventional solid-state tS capacitor. 1.11... Anode body, 2.12... Anode lead, 3
... graphite layer, 14 ... conductor carbon layer, 5.
15... Cathode conductor layer, 6, 16... Anode lead wire. 7.17... Cathode lead lead wire, 8.18... Insulating resin layer. 2nd fig. 3 times ρ 25 ρ engineering 26757) Time! Shishi “ζH) Trap Rice Product

Claims (2)

[Claims] (1) In a solid electrolytic capacitor in which an oxide film layer, a semiconductor layer, a conductive carbon layer, and a cathode conductive layer are sequentially formed on an anode body of a valve metal, the conductive carbon layer is made of a water-insoluble resin, a heat-resistant A solid electrolytic capacitor characterized by being made of conductive inorganic powder and conductive carbon powder. (2) The water-insoluble resin, the heat-resistant inorganic powder, and the conductive carbon powder contain 18 to 200 parts by weight of the heat-resistant inorganic powder and 12 to 180 parts by weight of the conductive carbon powder per 100 parts by weight of the water-insoluble resin.
The solid electrolytic capacitor according to claim 1, characterized in that the solid electrolytic capacitor consists of parts by weight.