JPH04101407A - Solid electrolytic capacitor - Google Patents

Abstract

PURPOSE:To achieve a solid electrolytic capacitor in which there is no mechanical stress on the dielectric coating or the conductive polymer film and which has more stable features by independently pinching and welding multiple electrodes sheets to the slit sections formed in the tip of exposed lead terminals and forming a conductive polymer film on the dielectric coated electrode sheet. CONSTITUTION:After roughening the surface of a high purity aluminum sheet in a hydrochloride solution, a dielectric coating is formed using an ammonium adipate solution to create a planner electrode. Two sheets of this aluminum electrodes sheet and an exposed lead terminal 3 with multiple slits 3a on the tip are used. The electrode sheets 1 are pinched in the slits and are welded from the front and back sides of the exposed lead terminal 3. A polypyrrole layer is formed on the surface of the dielectric layers on these electrode sheets 1. After this, a carbon layer is formed and an anode is created using a silver paste or other conductive paste. An epoxy resin is added to form the exterior and the solid electrolytic capacitor is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a solid electrolytic capacitor using a conductive polymer membrane such as polypyrrole as a solid electrolyte.

Conventional technology Solid electrolytic capacitors using valve action metal foil are made by oxidizing aluminum foil, which has been roughened in advance, to form a dielectric film, connecting lead terminals to the foil, and then connecting it through a separator. A capacitor element wound opposite to a similar cathode foil is impregnated with heat-molten TCNQ complex and stored in a cylindrical space, or a carbon layer is formed by polymerizing pyrrole on a flat anode body. It has been put into practical use, with a cathode lead terminal connected using silver paste and a resin exterior.

Problem to be Solved by the Invention In the case of a wound type condenser as described above,
Since a cylindrical case is used, the external dimensions are restricted, making it difficult to meet market demands for lower profile.

When six flat plate electrodes are used, the capacitance is limited by the electrode area, so it is not possible to increase the capacitance, and for this reason, are there any attempts to avoid bending longer flat foils? However, the dielectric film and the polymer dielectric film formed on the dielectric film were easily destroyed, which was a major drawback for increasing capacity.

Means for Solving the Problems The present invention aims to solve the above-mentioned problems by applying a chemical conversion treatment to a valve metal foil to form a dielectric film, and then cutting a plurality of electrode foils into predetermined dimensions. A solid electrolytic capacitor characterized in that a conductive polymer film is formed on a dielectric film of the electrode foil by independently sandwiching and welding the slit portion formed at the tip of a lead terminal.

Function As described above, the solid electrolytic capacitor of the present invention has a plurality of anode foils stacked at intervals and connected independently at the connection part of one lead terminal, so that the solid electrolytic capacitor of the present invention has a multilayer type in terms of electrical characteristics. This is similar to the above, and there is no need to bend the electrode foil portion, and there is no mechanical stress on the dielectric film or conductive polymer film, resulting in a solid electrolytic capacitor with more stable characteristics.

Example A high-purity aluminum foil with a thickness of 100 μm was roughened by alternating current etching in an aqueous solution of hydrochloric acid, and then a dielectric film equivalent to 50 V was formed in an aqueous solution of ammonium 7 dipate, as shown in Figure 3. A flat plate electrode was formed using a conventional method.

Figure 5 shows an electrode foil similar to that shown in Figure 3, bent from the middle, and Figure 1 shows an example of the present invention; Using a pull-out lead terminal having a plurality of slits 3a formed at the tip thereof, an electrode foil 1 is held under pressure at the slit portion, and further welded from both the front and back sides of the pull-out lead terminal.

After forming a polypyrrole layer on the dielectric layer of the electrode foils shown in FIGS. 1, 3, and 5, a carbon layer is formed, and a silver paste etc. is formed as shown in FIGS. 2, 4, and 6. A solid electrolytic capacitor was fabricated by drawing out the cathode using conductive paste and covering it with epoxy resin. Table 1 shows the results of measuring the electrical properties.

According to the present invention, compared to conventional products, ESR, equal series resistance,
It has been proven that both leakage current is low and it is extremely effective.

Although the embodiment has been described using two electrode foils, the same applies to three or more electrode foils.

In addition, in the above embodiments, the cathode was constructed using a carbon layer and a silver paste layer, but the cathode may also be constructed using a known technique with an anode electrode foil and a cathode electrode foil facing each other. For example, one electrode foil may be independently held between the slit portions, and the other electrode foil may be welded to one side of the holding portion. In any case, it is sufficient that the anode foils are overlapped and independently connected at intervals.

Effects of the Invention As described above, a solid electrolytic capacitor formed by welding a plurality of electrode foils together under pressure using the external lead terminal having a slit portion according to the present invention not only allows the shape of the capacitor element to be miniaturized. , it is possible to improve the electrical properties like the laminated type, and it has great industrial and practical value.

[Brief explanation of drawings]

Fig. 1 is a perspective view of an embodiment of the connection between the lead-out terminal and the electrode foil of the solid electrolytic capacitor of the present invention, and Fig. 2 is a perspective view of an embodiment of the connection between the lead-out terminal and the electrode foil of the solid electrolytic capacitor of the present invention. 3 and 5 are perspective views of the main parts of the solid electrolytic capacitor element connecting the lead terminals and the electrode foils of the conventional solid electrolytic capacitor. , 4 and 6 are perspective views of the main parts of a conventional solid electrolytic capacitor element. 1.2: Electrode foil 3: Anode lead terminal, 3a mini slit 4: Cathode lead terminal

Claims (1)

[Claims] A plurality of electrode foils, which are chemically treated to valve metal foil to form a dielectric film and cut to predetermined dimensions, are independently sandwiched and welded to a slit portion formed at the tip of a drawer lead terminal. A solid electrolytic capacitor characterized in that a conductive polymer film is formed on the dielectric film of the electrode foil.