JPH0439219B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a method for manufacturing an electrolytic capacitor using an organic semiconductor as an electrolyte. [Temporary background of the invention and its problems] Generally, an electrolytic capacitor whose dielectric is an oxide of a valve metal such as aluminum or tantalum has a pair of anode and cathode foils made of aluminum foil and a pair of anode foils also made of aluminum. The lead terminals are connected, and the pair of anode and cathode foils are wound with a spacer interposed between them, and then impregnated with an organic or inorganic liquid electrolyte as a driving electrolyte and housed in a case, and the opening of the case is sealed with a sealing body. It is sealed and sealed. However, the liquid electrolyte tends to increase its specific resistance at low temperatures, resulting in extremely poor low-temperature characteristics and lacks reliability when used in a low temperature range. Various electrolytic capacitors have been proposed in which a fixed electrolyte is a charge transfer complex type organic semiconductor that is small and provides excellent temperature characteristics and high frequency characteristics. As the organic semiconductor, a TCNQ complex consisting of a nitrogen-containing polymer such as polyvinylpyridine as an electron donor and TCNQ as an acceptor is often used in practice. Conventionally, the TCNQ complex layer was formed on the surface of the electrode foil by dissolving the TCNQ complex in an appropriate organic solvent and coating and drying it, or by immersing the TCNQ complex in a thermal melting tank in which the TCNQ complex was once thermally melted. Alternatively, methods such as vacuum evaporation of TCNQ complexes have been taken. However, the technique for forming the TCNQ differential layer described above has the following problems. That is, in the case of the organic solvent solution method, the solubility of the TCNQ complex in the organic solvent is low, so that it is not possible to form a film with sufficient thickness. TCNQ
The complex is easily decomposed by organic solvents and stable conductivity cannot be obtained. After drying, the TCNQ complex recrystallizes into needle-like shapes and does not adhere closely to the electrode foil. In addition, in the case of the thermal melting method, the chemical stability in the molten state is extremely poor, and the conductivity decreases in a short period of time.In addition, many TCNQ complexes are in a thermally decomposed form, and tend to decompose before melting, resulting in extremely unstable properties. It was becoming. Furthermore, in the case of vapor deposition, it is impossible to form a TCNQ complex film on a surface other than the smooth electrode foil or the surface facing the evaporation source, which increases capacity and
It was difficult to reduce the loss (tanδ). [Purpose of the Invention] The present invention has been made in view of the above points, and is an electrolytic method that improves the contact efficiency between the electrode foil and the TCNQ complex, stabilizes various characteristics for a long time, and contributes to miniaturization. The object of the present invention is to provide a method for manufacturing a capacitor. [Summary of the Invention] The method for manufacturing an electrolytic capacitor of the present invention provides a method for manufacturing an electrolytic capacitor, in which both sides of one end in the width direction of an anode foil made of a band-shaped valve metal with a dielectric oxide film formed on the surface are used as a margin, and the surface other than the margin is A capacitor element obtained by depositing a TCNQ complex to form a TCNQ complex film, forming a cathode film on the surface of the TCNQ complex film to form a strip-shaped composite layer, and then winding the strip-shaped composite layer in the length direction. is heated by high-frequency induction to melt the TCNQ complex film, impregnating and adhering to the pores of the anode foil and the cathode film, and then forming electrode extension parts on both end faces of the capacitor element. It is something. [Embodiment of the Invention] An embodiment of the present invention will be described below. That is, as shown in FIG. 1, both sides of one end in the width direction of an anode foil 2 made of a strip of aluminum on which a dielectric oxide film 1 is formed by anodic oxidation treatment are defined as a margin 3, and the anode foil excluding the margin 3 2 on the surface
A TCNQ complex film 4 is formed by vacuum evaporation of the TCNQ complex, and a conductive paste using, for example, silver or copper powder as a copper conductive medium is applied to the surface of the TCNQ complex film 4 excluding the end face located in the margin portion 3. - The cathode film 5 is formed by drying or vacuum evaporation of a metal such as silver or copper to obtain the strip-shaped multilayer body 6. Then, the capacitor element 7 obtained by winding the strip-shaped multilayer body 6 in the length direction is inserted into the center of the heating coil 8 as shown in FIG.
A high frequency current of 22 OK Hz is passed through the heating coil 8 and the TCNQ complex film 4 is rapidly and briefly melted by the current heat generated in the anode foil 2 constituting the capacitor element 7, thereby etching the pores of the anode foil 2. Then, as shown in FIG. 3, silver or copper paste is applied to both end faces of the capacitor element 7 and dried. A lead-out portion 9 is formed, and the electrode lead-out portion 9
The lead terminal 10 is attached to the terminal, and then an exterior (not shown) is applied. According to the manufacturing method of the electrolytic capacitor configured as described above, compared to the conventional method of simply vapor depositing TCNQ complex, TCNQ complex is produced by high-frequency induction heating.
As the complex film 4 is melted, the TCNQ complex penetrates into the pores of the roughened surface of the anode foil 2 and into the cathode film 5, and the TCNQ complex film 4 is tightly adhered to these parts, resulting in large capacity, low tanδ, and long life. It becomes possible to In addition, the TCNQ complex film 4 is melted by short-time heating using high-frequency induction heating, and there is no need for long-term heating unlike the conventional hot-melting immersion method for TCNQ complexes, so thermal decomposition of the TCNQ complex is extremely small and the characteristics are maintained. The variation is small, and the TCNQ complex does not cause recrystallization and has good adhesion to the anode foil 2 and cathode film 5 compared to the solution coating method, and is extremely effective in improving and stabilizing properties. Next, an example of comparison between an embodiment of the present invention and a conventional reference example will be described. Example A The surface of a high-purity aluminum (purity 99.99%) foil was roughened by electrolytic etching, and then 2,2'-bipyridinium (TCNQ) ₂ was applied to the surface of the strip-shaped anode foil on which a dielectric oxide film was formed by anodizing treatment. The complex is vacuum evaporated to form a 5 μm thick TCNQ complex film, and then Ag is vacuum evaporated onto the TCNQ complex film to reduce the thickness.
A capacitor element obtained by winding a band-shaped multilayer body having the configuration shown in Fig. 1 obtained by forming a 10 μm cathode film was subjected to high-frequency induction heating treatment for 5 seconds by the means shown in Fig. 2. Then, Ag paste is applied to both end faces of the capacitor element and dried to form an electrode lead-out part, a lead-out terminal is welded to the electrode lead-out part, and an epoxy resin is coated as an exterior structure. capacitor. Reference Example B A capacitor element formed with the same configuration as Example A above was coated with Ag paste on both end faces without high-frequency induction heating treatment and dried to form an electrode lead-out portion, and the lead-out terminal and exterior structure were changed to the same structure as in Example A above. An electrolytic capacitor with a rating of 25WV and 1μF that has the same configuration as . Reference Example C A capacitor element formed by winding an anode foil prepared with the same configuration as in Example A above and a cathode foil with a roughened surface of 99% pure aluminum foil through a glass cloth was heated and melted in advance. ′-bipyridinium (TCNQ) ₂ complex solution - impregnated,
After that, it was pulled up, cooled, and made into a metal case exterior.
525WV 1μF electrolytic capacitor. Therefore, the high temperature (105°C) load life of Example A according to the present invention and conventional Reference Examples B and C is
The results of examining tanδ characteristics, leakage current characteristics, and comparison of molten volume are shown in Figures 4 and 5 and the table.

[Table] As is clear from Figures 4 and 5, tanδ
Both characteristics and leakage current characteristics of Example A were more stable than Reference Examples B and C, demonstrating the excellent effect of the present invention on high temperature load life. Also, as is clear from the above table, with the same rating, Example A is 1/3 the volume ratio of Reference Example B, and Reference Example C
It was demonstrated that it is possible to significantly reduce the size to 1/5 compared to that of Reference Example B or C, and that it is possible to significantly increase the capacity if the volume is the same as Reference Example B or C. In the above embodiment, aluminum foil was used as an example of the band-shaped valve metal foil, but the same effect can be obtained even if the valve metal foil is made of tantalum, niobium, titanium, or the like. Furthermore, in the above examples, 2,2'-bipyridinium (TCNQ) ₂ complex was exemplified as the TCNQ complex, but for example, 4,4'-dimethylbipyridinium (TCNQ) ₂ complex or other TCNQ complexes were explained.
The same effect is obtained when applied to a complex. [Effects of the Invention] According to the present invention, the TCNQ complex can be adhered uniformly and completely to the inside of the pores on the surface of the anode foil, and can also be adhered to the inside of the cathode membrane, thereby contributing to stabilization of characteristics and miniaturization. A method for manufacturing an electrolytic capacitor with high commercial value can be obtained.

[Brief explanation of drawings]

FIG. 1 and FIG. 3 are for explaining one embodiment of the present invention, and FIG. 1 is a perspective view of a strip-shaped multilayer body;
FIG. 2 is a schematic diagram showing high-frequency induction heating means for a capacitor element, FIG. 3 is a sectional view showing the capacitor element after forming an electrode extraction part, and FIG.
FIG. 5 is a time-leakage current characteristic curve diagram. 1... Dielectric oxide film, 2... Anode foil, 3...
Margin area, 4...TCNQ complex film, 5... cathode film,
6... Band-shaped multilayer body, 7... Capacitor element, 8...
... Heating coil, 9... Electrode extraction part.

Claims (1)

[Claims] 1. means for forming a TCNQ complex film by vacuum-depositing a TCNQ complex on the surface of an anode foil made of a band-shaped valve metal on which a dielectric oxide film is formed, with both sides of one end in the width direction of the anode foil as a margin; The TCNQ
means for forming a cathode film on the surface of the complex film to obtain a strip-like multilayer body; means for winding the strip-like multilayer body to form a capacitor element; and heating the element by high-frequency induction to
An electrolytic capacitor comprising means for impregnating and adhering a TCNQ complex to the pores of the anode foil and the cathode film, and means for forming electrode extension parts on both end surfaces of the capacitor element after the means. manufacturing method.