JP2578783Y2 - Solid electrolytic capacitors - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid electrolytic capacitor using an organic semiconductor having an improved winding structure of a capacitor element as a solid electrolyte.

[0002]

2. Description of the Related Art In general, a dry foil electrolytic capacitor is formed by connecting a pair of lead terminals also made of aluminum to a pair of positive and negative foils made of, for example, high-purity aluminum foil.
A capacitor element, which is wound between a pair of positive and negative electrode foils via a spacer, is impregnated with a driving electrolyte and stored in a case, and the case opening is sealed with a sealing body.

The driving electrolyte uses an organic carboxylate such as ammonium adipate in an organic solvent such as ethylene glycol.
There is a limit to the improvement of δ characteristics, and there is a problem to be solved to satisfy market demands, such as low resistivity at high temperature, extremely low temperature characteristics and poor reliability for use in a wide temperature range. I was

Therefore, in recent years, TCN has been
Various devices using an organic semiconductor comprising a Q complex have been proposed and partially put into practical use.

[0005] As a method of impregnating a capacitor element with a TCNQ complex, there are generally a solution impregnation method, a dispersion impregnation method, and a vacuum evaporation method. Various ideas have been devised for use.

In particular, as the solid electrolyte condition of the electrolytic capacitor, it is required that the resistance value itself affecting the tan δ and the equivalent series resistance as a capacitor characteristic is small, and that the specific resistance value be stable even at high temperatures, especially at high temperatures. is important.

[0007] From the above, TC to the capacitor element
In order to impregnate the inside of the device uniformly and in a necessary amount as the means for impregnating the NQ complex, a heat-melt liquefaction treatment is effective according to a conventionally proposed patent publication or technical literature.

The specific means of the heat-melt liquefaction treatment is as follows:
The capacitor element preheated is stored in the desired TCNQ complex solution that has been heated and melted in an outer case, and the fibers of insulating paper as spacers constituting the capacitor element and the capillary phenomenon due to the fine etching pits of the electrode foil. It is impregnated with the TCNQ complex solution and then cooled and solidified. However, at the time of impregnation, the gap between the inner diameter of the container and the outer diameter of the capacitor element is also filled with the molten organic semiconductor, and the liquid level is changed to the opening of the outer case. May reach the inner wall where the part is located.

That is, the organic semiconductor is present on the wall surface where the filling resin as the sealing member should be located in the outer case, and when the epoxy resin as the sealing member is filled in such a state, the inner wall of the outer case and Adhesion with the epoxy resin becomes incomplete, and outside air and moisture easily enter from this portion, causing a problem of causing a decrease in capacitance and an increase in loss.

If the amount of the TCNQ complex solution present in the outer case tends to be larger than the required amount due to the variation in the amount of the TCNQ complex solution, the TCNQ may be passed through the inner surface of the case and / or between the outer surfaces of the element.
The Q complex solution adheres to the extraction terminal, and as a result, there is a problem that the leakage current increases.

[0011]

SUMMARY OF THE INVENTION As described above, the solid electrolytic capacitor having the above-mentioned structure is filled with resin as a sealing body because the TCNQ complex solution easily adheres to the outer surface of the capacitor element during the TCNQ complex solution impregnation step. In addition, there is a risk that the TCNQ complex solution adhered to the outer surface of the capacitor element adheres to the lead-out terminal, resulting in deterioration of various characteristics.

The present invention has been made in view of the above points, and by improving the outer surface structure of the capacitor element, the impregnation of the TCNQ complex solution has been improved, and the rise of the TCNQ complex solution has been suppressed. It is an object of the present invention to provide a solid electrolytic capacitor which can greatly contribute to eliminating a characteristic deterioration factor.

[0013]

A solid electrolytic capacitor according to the present invention is wound with a spacer between an anode foil and a cathode foil made of a valve action metal having a lead terminal attached at an arbitrary position, and a winding tape. In a solid electrolytic capacitor in which a sealed capacitor element is housed in a case and impregnated with an organic semiconductor, and the opening of the case is sealed with a filling resin, the width of the winding tape is at least half the length of the capacitor element. Wherein the surface opposite to the adhesive surface has a water-repellent surface, and the adhesive surface is in contact with at least the periphery of the capacitor element and is wound once.

[0014]

According to the above construction, at least one half of the wound outer peripheral surface of the capacitor element is covered with the water-repellent surface, so that the adhesion of the TCNQ complex liquid to the outer peripheral surface of the capacitor element does not occur. The inner wall of the case is completely in contact with the filling resin, the insulation between the capacitor element and the outside air is improved, and the TCNQ complex liquid does not adhere to the lead-out terminal through the outer peripheral surface of the capacitor element, and the sealing property is good. The isolation from the outside air is improved, and the cause of the characteristic deterioration is eliminated.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. That is, as shown in FIG. 2, first, the surface of the aluminum foil was roughened with an etchant to increase the surface area, and then the anode foil 1 on which an anodic oxide film was formed and the surface of the aluminum foil were roughened with the etchant in the same manner as described above. A spacer 3 made of kraft paper, manila paper, or the like is interposed between the cathode foils 2 obtained by enlarging the anode foil 1 and the cathode foil 2 on the way.
An anode lead terminal 4 and a cathode lead terminal 5 are attached to and wound around arbitrary portions of the base material, and are wound and fixed, as shown in FIG. 3, by heating one surface of a base material 6 made of, for example, polyester, polypropylene, polyimide or the like. Using a wrapping tape 9 having a curable or thermoplastic adhesive surface 7 and the other surface having a water-repellent surface 8 made of, for example, a silicone resin or an oil film,
The adhesive surface 7 is wound around the winding surface at least one turn to form the capacitor element 10.

In this case, the width of the wrapping tape 9 is set to be at least half the length of the capacitor element 10, and at least half of the circumference of the capacitor element 10 becomes the water-repellent surface 8.

Then, as shown in FIG. 4, an organic semiconductor made of a TCNQ complex is put in a case 11 made of, for example, aluminum, and the organic semiconductor is heated and melted to form an organic semiconductor melt 12, which is shown in FIG. As shown in the figure, the capacitor element 10 is housed in the case 11 in a preheated state,
The organic semiconductor melt 12 is impregnated into the capacitor element 10, then cooled and solidified, and the remaining organic semiconductor melt 12 that is not impregnated is solidified on the bottom surface of the case as an organic semiconductor 13. The part is sealed with a filling resin 14 made of, for example, an epoxy resin.

In the solid electrolytic capacitor having the above-described structure, at least half of the periphery of the capacitor element 10 is the water-repellent surface 8 constituting the winding tape 9, so that the impregnation of the organic semiconductor melt 12 is performed. Time capacitor element 10
The occurrence of capillary action is suppressed between the case 11 and the inner wall of the case 11, and the organic semiconductor melt 12 does not creep up, and the case 11 and the filling resin 14 adhere when the opening of the case 11 is sealed with the filling resin 14 made of epoxy resin. Is good, and the capacitor element 10 and the outside air are shut off, and there is no decrease in capacitance change or increase in loss change even during long-time use, which can greatly contribute to improvement of characteristics.

Next, an example of comparison between the embodiment A of the present invention and the conventional example B will be described.

That is, an anode foil having a width of 5 mm and a length of 25 mm and a cathode foil having a width of 5 mm and a length of 35 mm are used.
A thermosetting adhesive surface 7 is provided on one side of a μm polyimide,
8. Using a wrapping tape coated on the other side with a silicone heat-resistant oil to make it a water-repellent surface, the wrapped capacitor element is 6.3 mm in diameter and has a height of 9 mm in which an organic semiconductor melt is stored.
Leakage current distribution and capacitance of Example A housed in an 8 mm aluminum case and Conventional Example B which was the same as Example A except that no water-repellent surface was provided as a wrapping tape As a result of examining the change and the loss change, the results were as shown in FIGS.

The organic semiconductor uses a TCNQ complex of N-n-butylisoquinolinium in both Example A and Conventional Example B, and the rating is 16 V-47 μF in both Example A and Conventional Example B.

As apparent from FIGS. 5 to 7, in the conventional example, the absolute value of the leakage current value is high, the variation is large, and the capacitance change rate with time is extremely large.
Furthermore, while the fluctuation of loss over time is large,
In Example A, the leakage current value and the variation were small,
Further, the capacitance change rate with respect to time and the fluctuation deterioration of the loss are small and the excellent effect of the present invention can be seen.

However, in the case of the present invention, this difference is caused by providing a water-repellent surface on the other surface as a wrapping tape structure, and by positioning this water-repellent surface on the peripheral surface of the capacitor element. It is possible to prevent the organic semiconductor melt from splashing out during the impregnation process and to prevent the organic semiconductor melt from adhering to the inner wall of the case opening. This is due to the improvement in performance.

In the above embodiment, the silicone tape is used as an example of the water-repellent surface of the wrapping tape. However, the present invention is not limited to this. Of course, you can do that.

[0025]

According to the present invention, by using a tape having a water-repellent surface on one surface and by positioning the water-repellent surface on the peripheral surface of the capacitor element, the sealing performance is improved and the capacitance and the loss are improved. Further, a solid electrolytic capacitor using an organic semiconductor as a solid electrolyte without deterioration in leakage current characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a solid electrolytic capacitor according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a capacitor element constituting FIG. 1;

FIG. 3 is a partially cut-away cross-sectional view illustrating the winding tape according to the embodiment of the present invention;

FIG. 4 is a cross-sectional view showing a heat-melted state of an organic semiconductor.

FIG. 5 is a leakage current characteristic distribution diagram.

FIG. 6 is a diagram showing a capacitance change characteristic curve.

FIG. 7 is a loss change characteristic curve diagram.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anode foil 2 Cathode foil 3 Spacer 4 Anode lead-out terminal 5 Cathode lead-out terminal 6 Base material 7 Adhesive surface 8 Water-repellent surface 9 Winding tape 10 Capacitor element 11 Case 12 Organic semiconductor melt 13 Solidified organic semiconductor 14 Filling resin

Claims (1)

(57) [Scope of request for utility model registration] 1. A capacitor element wound around a spacer between an anode foil and a cathode foil made of a valve action metal and having a lead terminal attached at an arbitrary position and wound with a tape for fastening, is housed in a case, and an organic semiconductor is provided. In a solid electrolytic capacitor in which the opening of the case is sealed with a filling resin, a water-repellent surface is formed on the surface opposite to the adhesive surface with a width of 1/2 or more of the length of the capacitor element as the winding tape. A solid electrolytic capacitor wherein the adhesive surface is abutted at least around the capacitor element and is wound once.