Method for manufacturing solid electrolytic capacitor using functional polymer electrolytic composition

Abstract

Disclosed is a method for manufacturing a solid electrolytic capacitor using a functional polymer composition. The method comprises immersing the rolled aluminum electrolytic capacitor device in polyaniline solution with high electric conductivity to impregnate the device with polyaniline, drying the impregnated device in a drying oven which is maintained at constant temperature to fully remove the solvent, inserting the dried device to a capacitor aluminum can and then sealing with epoxy resin, to manufacture a solid electrolytic capacitor using a functional polymer. As such, the impregnation can be performed well at not only normal temperature and pressure, but also high temperature and reduced pressure. The solid electrolytic capacitor has the advantages of high capacity, low impedance and low ESR, and also, low manufacturing cost, simple processes and high reliability.

Description

[0001] 1. Field of the Invention[0002] The present invention relates to a method for manufacturing a solid electrolytic capacitor with high performance and high reliability, by applying a solution of a. functional polymer composition useful as a solid electrolyte, and a rolled aluminum device.[0003] 2. Description of the Prior Art[0004] Usually, a solid electrolytic capacitor has a structure comprising an electrode of metals, such as aluminum (Al) or tantalum (Ta), acting as an anode; an oxide film formed thereon via chemical treatment, as a dielectric layer; and a solid electrolyte-attached conductive layer of substances including graphite or silver formed on the dielectric layer, as a part of a cathode. In this caser as the solid electrolyte, use may be made of metal oxides such as manganese dioxide and lead oxide, TCNQ (7,7',8,8'-tetracyanoquinodimethane) complex, which is an organic semiconductor, and polypyrrole, which is a conductive polymer,[0005] Though generally used in tan...

AI Technical Summary

Benefits of technology

[0011] As mentioned above, the electrode lead is attached to each of the aluminum etching thin film and the cathode thin film and then rolled, together with a separator paper, to prepare a rolled device, which is simply immersed in the solution of conductive polymer solid electrolyte at normal temperature and pressure, thereby forming a solid electrolyte layer with high impregnation efficiency. In consequence, the solid electrolytic capacitor which is advantageous in terms of easier impregnation, more excellent leakage current properties and larger electrostatic capacity, can be prepared according to the present invention, compared with conventional solid electrolytic capacitors.

Problems solved by technology

Though generally used in tantalum (Ta) electrolytic capacitors, manganese dioxide can be applied to aluminum electrolytic capacitors, but with significant difficulty.

But, in the case of aluminum (Al) electrolytic capacitor, such thermal decomposition impairs a dielectric aluminum oxide film with concurrent drastic decrease in pressure resistance.

However, TCNQ complex is poorly resistant to heat.

In particular, TCNQ complex suitable for the dissolution-impregnation should have a dissolution point of 270.degree. C. or lower owing to its decomposition point being about 290.degree. C., but this temperature is too low to provide resistance to soldering.

However, the impregnation of polypyrrole causes the pressure resistance of dielectric oxide film to be greatly lowered, as in manganese dioxide.

Additionally, the application range of polypyrrole is limited.

For example, the electrode in the flat form can be impregnated with polypyrrole, whereas the rolled form is very difficult to impregnate with polypyrrole.

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