JPH062675U - Solid electrolytic capacitor - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the amount of organic semiconductor used, prevent the organic semiconductor from adhering to the lead terminal, and prevent mechanical fluctuations of the capacitor element to improve the leakage current characteristics. [Structure] A rod-shaped body 6 made of metal is wound as a winding core,
The organic semiconductor is heat-melted and impregnated into the capacitor element 7 in which the rod-shaped body 6 is left as it is, and the organic semiconductor is housed in the case 8.
The opening is sealed with a sealing body 11 made of resin.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a solid electrolytic capacitor using an organic semiconductor having an improved element structure as a solid electrolyte.

[0002]

[Prior art]

 Generally, a dry foil type electrolytic capacitor has, for example, a pair of positive and negative electrode foils made of high-purity aluminum foil and a pair of lead terminals also made of aluminum, and a spacer interposed between the pair of positive and negative electrode foils. The capacitor element formed by winding the capacitor is impregnated with a driving electrolyte solution and housed in a case, and the case opening is sealed with a sealing body.

Although the driving electrolyte uses an organic carboxylic acid salt such as ammonium adipate in an organic solvent such as ethylene glycol, there is a limit to the improvement of tan δ characteristics, and at a low temperature. There was a problem to be solved in order to satisfy the market demands, such as an increase in resistivity and extremely low temperature characteristics, and lack of reliability for use in a wide temperature range.

Therefore, in recent years, various types of organic electrolytes made of a TCNQ complex have been proposed instead of the driving electrolyte, and some of them have been put into practical use.

As a method for impregnating a TCNQ complex into a capacitor element, there are generally a solution impregnation method, a dispersion impregnation method, and a vacuum vapor deposition method. However, the characteristics of the TCNQ complex change under various conditions, and it is an extremely difficult substance to handle. Therefore, various measures have been taken in using it.

[0006] In particular, as a condition of the solid electrolyte, there is a small resistance value per se that affects tan δ as a capacitor characteristic and an equivalent series resistance, and a stable specific resistance value at a temperature, especially at a high temperature. is important.

From the above, as a means for impregnating a capacitor element with a TCNQ complex industrially, in order to uniformly impregnate the inside of the element with a required amount, the heating melt liquefaction treatment is effective according to the conventionally proposed patent publications or technical literatures. It is said that.

The specific means of the heat-melting and liquefying treatment is to store the capacitor element, which is preheated in the desired TCNQ complex solution, which is placed in an outer case and heated and melted, and the insulating paper ( It is impregnated through fine etching pits of the spacer foil and the electrode foil.

However, in the case of the wound type capacitor element configuration, since the core hole from which the core is drawn is formed as a void, when the capacitor element is stored in the TCNQ complex liquid heated and melted in the outer case, The TCNQ complex solution jumps out through this void and adheres to the lead terminal.

There is no problem if the TCNQ complex solution adheres to the part where the anodized film of the lead terminal is formed, but if it adheres to the part where the anodized film does not exist, the leakage current increases and a short circuit occurs at the same time. At the same time as it has a problem of being defective, the amount of TCNQ complex used as an organic semiconductor must be determined in consideration of the amount flowing into the core hole. However, since the TCNQ complex is expensive, market demand is strong. It was an alienation factor in reducing the cost of capacitors.

Further, when the epoxy resin used as the sealing body is not sufficiently flown into the void as the winding core hole of the capacitor element, and when the epoxy resin is heated in a high temperature atmosphere and the air in the void is not discharged. In addition to swelling and rising to the epoxy resin surface, resulting in a poor appearance, it also had the factor of causing characteristic changes due to a local decrease in the resin layer due to reliability tests, especially moisture resistance. .

Further, due to the presence of the void portion as the core hole, slight thermal expansion / contraction in the temperature cycle test or the like easily moves toward the core hole, and the leakage current is further increased due to cracks in the oxide film due to the fluctuation. I also had the problem of doing it.

[0013]

[Problems to be solved by the device]

 As described above, in the solid electrolytic capacitor configured as described above, due to the presence of the void portion as the winding core hole of the capacitor element, the TCNQ complex liquid as the organic semiconductor jumps out of the void portion during the impregnation process, increasing the leakage current, This is not only a cause of short-circuit failure, but also a cause of deterioration of various characteristics due to mechanical fluctuations of the capacitor element, and a problem of useless use of TCNQ complex as an organic semiconductor. It was

The present invention has been made in view of the above points, and improves the impregnation property of the TCNQ complex, suppresses mechanical fluctuations of the capacitor element, has various characteristics, and is highly cost-effective. It is intended to provide a solid electrolytic capacitor that can contribute.

[0015]

[Means for Solving the Problems]

 The solid electrolytic capacitor according to the present invention is a solid electrolytic capacitor formed by impregnating an organic semiconductor into a capacitor element wound with a spacer interposed between an anode foil and a cathode foil made of a valve metal with lead terminals attached at arbitrary locations. In the capacitor, the core hole of the capacitor element is closed by a rod-shaped body made of metal, ceramic or heat resistant resin.

[0016]

[Action]

 According to the above configuration, since the void portion as the winding core hole of the capacitor element is closed by the rod-shaped body made of metal, ceramic or heat resistant resin, waste of the amount of TCNQ complex used as the organic semiconductor is saved. The effective electrode part is quickly impregnated without sticking to the lead-out terminal, and there is no mechanical fluctuation of the capacitor element even at high temperatures during the manufacturing process, eliminating the factor of characteristic deterioration.

[0017]

【Example】

 An 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 is roughened with an etching solution to increase the surface area, and then the anode foil 1 on which the anodized film is formed and the surface of the aluminum foil are roughened with the same etching solution as described above. A spacer 3 made of kraft paper or manila paper is interposed between the cathode foils 2 whose surface area has been increased, and the anode lead-out terminal 4 or the cathode lead-out terminal is provided at any place on the anode foil 1 and the cathode foil 2 in the middle. 5 is attached, and a capacitor element 7 is formed by winding a rod-shaped body 6 made of metal, for example, a round shape having a diameter of 1 mm or a polygonal cross section having a polygonal shape as a winding core. At this time, the rod-shaped body 6 is left in the capacitor element.

Next, as shown in FIG. 3, an organic semiconductor made of a TC NQ complex is put into a case 8 made of, for example, aluminum, and the organic semiconductor is heated and melted to form an organic semiconductor melt 9 which is shown in FIG. As shown, the capacitor element 7 is stored in a case 8 in a preheated state, the organic semiconductor melt 9 is impregnated into the capacitor element 7, and then the capacitor element 7 is cooled and solidified, and the remaining organic semiconductor melt 9 not impregnated. Is an organic semiconductor 10 in a solidified state on the bottom surface of the case, and the opening of the case 8 is sealed by a sealing body 11 made of, for example, an epoxy resin.

In the solid electrolytic capacitor configured as described above, since the void portion as the winding core hole of the capacitor element 7 is closed by the rod-shaped body 6 made of metal, the solid electrolytic capacitor has the same winding core hole as the conventional structure. The phenomenon that the organic semiconductor molten liquid 9 crawls through does not occur, and therefore the factor that increases the leakage current is eliminated without adhering to the anode lead terminal 4 and the cathode lead terminal 5 with the minimum required amount of organic semiconductor melt 9 and is effective. Immediately impregnating the electrode part eliminates the factor of characteristic deterioration.

Further, even when accompanied by expansion and contraction such as in a temperature cycle test, since there is no winding core hole as in the conventional case, there is no factor of mechanical fluctuation of the capacitor element and it can greatly contribute to the improvement of characteristics such as leakage current. .

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

That is, an anode foil having a width of 5 mm and a length of 25 mm and an anode foil having a width of 5 mm and a length of 35 mm were used, and a manila paper having a width of 6 mm was wrapped around the aluminum round wire having a diameter of 1 mm to form a capacitor element. A capacitor element, in which the core was left as it was, was placed in an aluminum case having a diameter of 6.3 mm and a height of 9.8 mm in which the organic semiconductor melt was stored, and Example A prepared and a core having a diameter of 1 mm were used. Capacitor element formation Initial and temperature cycle tests of the conventional example B manufactured by the same method as the example A except that the core after withdrawal was removed (-55 ° C 30 minutes, 20 ° C 15 minutes, + 105 ° C 30 minutes, 20 ° C 15 As a result of investigating the change of the leakage current after 5 times (1 minute as one cycle) is shown in FIG. It was as shown in 1.

[0023]

[Table 1]

As is clear from FIG. 4 and Table 1, the conventional example B has a large variation deterioration of the leakage current characteristic due to the temperature cycle test, while the example A has little variation. You can see the excellent effect of. Further, it can be seen that, compared with the conventional example B, the example A can reduce the amount of the organic semiconductor used by about 13% without changing the characteristics of the product, which greatly contributes to the cost reduction.

In the above embodiments, the rod-shaped body for closing the winding core hole of the capacitor element is described by using metal as an example. However, ceramic or heat resistant resin may be used instead of metal. Good.

In the above embodiment, the technique of closing the core hole by leaving the core itself has been described as an example. However, after forming the capacitor element, the core is removed and prepared separately in the core hole. The same effect can be obtained if a plugging material is inserted and as a result the core hole is closed.

[0027]

[Effect of device]

 According to the present invention, it is possible to obtain a solid electrolytic capacitor using an organic semiconductor as a solid electrolyte, which can reduce the amount of organic semiconductor used and can suppress the fluctuation of leakage current due to temperature cycle.

[Brief description of drawings]

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

FIG. 2 is a developed perspective view showing a capacitor element which constitutes FIG.

FIG. 3 is a cross-sectional view showing a heated and melted state of an organic semiconductor.

FIG. 4 is a leakage current characteristic distribution chart.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anode foil 2 Cathode foil 3 Spacer 4 Anode lead terminal 5 Cathode lead terminal 6 Rod-like body 7 Capacitor element 8 Case 9 Organic semiconductor melt 10 Solid state organic semiconductor 11 Sealing body

Claims (1)

[Scope of utility model registration request] 1. A solid electrolytic capacitor obtained by impregnating an organic semiconductor into a capacitor element wound by interposing a spacer between an anode foil and a cathode foil made of a valve metal having lead terminals attached at arbitrary positions, A solid electrolytic capacitor, wherein the core hole of the capacitor element is closed by a rod-shaped body made of metal, ceramic or heat resistant resin.