JPH03215922A - Solid electrolytic capacitor and manufacture thereof - Google Patents

Abstract

PURPOSE:To avoid the passage of ions through water content wherein thick and minute high molecular resin layer is immersed by a method wherein a dielectric oxide film is formed on the surface of an anode body comprising a metal working as a valve and then the high molecular carbon resin layer and a metallic conductive paint layer are provided on a capacitor element whereon a solid electrolyte to be a cathode is formed. CONSTITUTION:A dielectric oxide film 12 is formed by anode-oxidizing an anode body 11 constituted by sintering tantalum and then a solid electrolyte 13 is formed of a manganese dioxide to be an anode by repeating thermochemical reaction, i.e., the impregnation with manganese nitride solution, and thermal cracking reaction so as to constitute a capacitor element 14. Next, the solid electrolyte 13 in this capacitor element 14 is provided with the bond properties onto a metallic conductive paint layer 15 for leading-out the anode while a high molecular carbon resin layer 16 for lowering the equivalent series resistance is formed. Furthermore, the layer 16 is coated with the metallic conductive paint layer 15 whereto a cathode terminal 17 is connected. Through these procedures, the passage of ions through water content wherein the thick and minute high molecular carbon resin layer 16 is immersed can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a solid electrolytic capacitor and a method for manufacturing the same.

Prior Art A conventional solid electrolytic capacitor is shown in FIG. 4C as shown in FIG.
A dielectric oxide film 2 made of tantalum oxide is formed on the first part of the anode body I made of tantalum, and this is covered with a solid electrolyte 3 made of manganese dioxide which is a true cathode,
Furthermore, after immersing a carbon layer 5 in an aqueous solution of colloidal graphite to provide adhesion to the metal conductive paint layer 4 for cathode projection and to lower the equivalent series resistance. The metal conductive paint layer 4 was formed thereon, and the cathode terminal 6 was connected to the metal conductive paint layer 4.

Problems to be Solved by the Invention In recent years, there has been a strong demand for high reliability and high performance for parts for electronic equipment in the industrial field. Many improvements have been attempted in solid electrolytic capacitors, including the following:

(1) Improvements to improve the reliability of the capacitor element itself (2) Improvements in cathode materials and cathode formation methods (3) Improvements in conductive paint for cathode extraction (4) Improvements in exterior resin materials and construction methods However, these improvements The improvement and improvement of the conventional solid electrolytic capacitor 6 shown in Fig. 4 are easy to apply to conventional solid electrolytic capacitors, and they are highly reliable without significantly increasing the cost. The reality is that there are almost no parts for electronic equipment used in the industrial field, where there is a strong demand for improved durability and performance, and that there are almost no parts that satisfy the requirement of excellent weather resistance (moisture resistance).

In view of these circumstances, the present invention is aimed at the industrial field where high reliability and high performance are strongly desired. The purpose is to provide a manufacturing method.

Means for Solving the Problems To achieve the above objects, the present invention involves forming a dielectric oxide film on the surface of an anode body made of a valve metal by anodic oxidation, and then forming a solid electrolyte to become a cathode by a thermochemical reaction. A polymer carbon resin layer and a metal conductive paint are provided on the formed layer.

The polymeric carbon resin layer is formed by immersing the capacitor element on which the solid electrolyte is formed in a mixed solution of a condensed polycyclic polynuclear aromatic compound and an aromatic polyhydric alcohol, and then using an acid catalyst. be.

Effects According to the present invention described above, the solid electrolyte serving as the cathode is covered with a polymeric carbon resin layer, and this polymeric carbon resin layer is thick and dense, and has excellent adhesion and conductivity. Therefore, it has the following effects. (
1) The thick and dense polymeric carbon resin layer can prevent the passage of invading ions in moisture. (2) Since the polymeric carbon resin layer has excellent adhesion, it is unlikely to peel off due to rapid temperature rise or temperature drop due to thermal shock or the like. (3) The polymeric carbon resin layer has excellent electrical conductivity and stable toughness.

Embodiments Hereinafter, embodiments of the present invention will be described based on the accompanying drawings. Figures 1 and 2 are a structural diagram and a sectional view showing a Kuntal solid electrolytic capacitor according to an embodiment of the present invention.
The anode body is formed by molding and sintering to a length of 1.6 m x 1.6 m, and is formed by anodization, and then a cathode is formed by repeating a thermochemical reaction, that is, impregnation with a manganese nitrate solution and a thermal decomposition reaction. A solid electrolyte 13 made of manganese dioxide is formed to constitute a capacitor element 14 of 35.times.1 .mu.F. A polymer carbon resin layer 16 is formed on the solid electrolyte 13 in the capacitor element 14 to provide adhesion to the metal conductive paint layer 15 for drawing out the cathode and to lower the equivalent series resistance. At the same time, the metal conductive paint layer 15 is further coated on the second side of this polymeric carbon resin layer 16, and the cathode terminal 17 is connected to this metal conductive paint layer 15.

In FIG. 2, 18 is a solder layer formed on the metal conductive paint layer 15, and a cathode lead wire 19 is connected to this solder layer 18. Reference numeral 20 denotes an anode 1 led out from the capacitor element 14, and an anode lead wire 2] is connected to the anode 1-20 by welding.

22 is an exterior resin.

Figure 3 (a), (b), and (c) show two solid electrolytic capacitors of the conventional example, example (1), and example (2), each having different conditions for forming carbon, at a test temperature of 12
The results are shown in the results of each test conducted at 1'C and a pressure of 2 atm. (a) is the capacitance change rate (%), (b) is the tangent of the loss angle (tan δ), (
c) shows the leakage current (ttA).

In addition, in the conventional example 2, the carbon layer 5 was formed by immersing the capacitor element in colloidal graphite 1 water and drying it at 120°C for 30 minutes. In Example (1), the capacitor element 14 is immersed in a mixed solution of pyrene, which is a condensed polycyclic polynuclear aromatic compound, and P-keysylene glycol, which is an aromatic polyhydric alcohol, and then immersed in diphenylsulfonic acid. The polymer carbon resin layer 16 is formed by acid catalyst treatment and curing at 150° C. for 30 minutes, and in Example (2), the capacitor element 14 is immersed in diphenylsulfonic acid. After the surface is subjected to acid catalyst treatment, it is immersed in a mixed solution of pyrene, a condensed polycyclic polynuclear aromatic compound, and P-xylene glycol, an aromatic polyhydric alcohol, and cured at 150°C for 30 minutes. , a polymer carbon resin 16 is formed.

As is clear from (a), (b), and (c) in FIG. It is excellent in both tangent (tan δ) and leakage current (μA).

Effects of the Invention As described above, according to the present invention, since a polymer carbon resin layer is provided on a capacitor element in which a solid electrolyte serving as a cathode is formed, the following advantages can be obtained.

(1) Since the polymer carbon resin layer is thick and dense, it can prevent the passage of ions in the invading moisture, thereby preventing the deterioration of the dielectric oxide film. Weather resistance (moisture resistance) because it can be significantly suppressed
improvement is expected.

(2) Since the polymeric carbon resin layer has excellent adhesion, it will not peel off due to sudden temperature rise or temperature stress such as thermal shock, and the resistance characteristics will be stable.

(3) Since the polymeric carbon resin layer has excellent conductivity and stable toughness, stable and good resistance characteristics can be obtained, and the stress resistance is also good, resulting in stable electrical performance over time. You can also obtain products with excellent properties.

(4) Although the present invention is a relatively simple method, it has a remarkable effect on improving the reliability of solid electrolytic capacitors, and is easy to apply to conventional processes, so it does not involve a significant increase in cost. It is of extremely great industrial value.

[Brief explanation of drawings]

Figure 1 is a structural diagram of a solid electrolytic capacitor showing an embodiment of the present invention, Figure 2 is a sectional view of the same capacitor, Part 3 (a)
(b) and (c) are characteristic diagrams showing the results of the Prenosha Cooker Test l of the champion solid electrolytic capacitors of the conventional example, examples (1) and (2), each having different conditions for forming carbon; FIG. 4 is a structural diagram showing a conventional solid electrolytic capacitor. 11... Anodity, 12... Dielectric oxide film, 13... Solid electrolyte, 14-... Capacitor element, 15... Metal conductive paint layer, 16・・・・・・
...Polymer carbon resin layer, 17...Cathode terminal.

Claims (6)

[Claims] (1) A dielectric oxide film is formed on the surface of the anode body made of a valve metal by anodizing, and then a solid electrolyte that becomes the cathode is formed by a thermochemical reaction.The capacitor element is covered with a polymer carbon resin layer, a metal conductive layer, Solid electrolytic capacitor with a paint layer. (2) The solid electrolytic capacitor according to claim 1, wherein the polymeric carbon resin layer has a main skeleton of a condensed polycyclic polynuclear aromatic compound. (3) The solid electrolytic capacitor according to claim 2, wherein the binding material that binds the main skeleton comprises an aromatic polyhydric alcohol. (4) A dielectric oxide film is formed on the surface of the anode body made of a valve metal by anodization, and then a solid electrolyte that becomes the cathode is formed by a thermochemical reaction. A method for manufacturing a solid electrolytic capacitor in which a polymeric carbon resin layer is formed by immersing the capacitor in a mixed solution of group polyhydric alcohol and then subjecting it to acid catalyst treatment. (5) After forming a dielectric oxide film on the surface of the anode body made of a valve metal by anodizing, and then applying an acid catalyst treatment to the surface of the capacitor element in which a solid electrolyte serving as a cathode was formed by a thermochemical reaction, A method for manufacturing a solid electrolytic capacitor in which a polymeric carbon resin layer is formed by immersing the solid electrolytic capacitor in a mixed solution of a condensed polycyclic polynuclear aromatic compound and an aromatic polyhydric alcohol. (6) The method for manufacturing a solid electrolytic capacitor according to claim 4 or 5, wherein the acid catalyst treatment for forming the polymeric carbon resin layer is performed using aromatic sulfonic acid.