JPH10144574A - Electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent exfoliation of the winding end of a winding tape, by winding a tape a specific number of turns around the outer peripheral part of a capacitor element, and by thermo-compression-bonding a part of at least winding end of a winding stop tape to the lower layer of the winding end of the winding stop tape. SOLUTION: An aluminum foil subjected to chemical conversion treatment is used as an electrode 1. Separator paper 3 is interposed between the anode and its opposing cathode foil 2, which are wound in a cylindrical type. Around the cylinder, a winding stop tape 4 is wound one turn or more, and a wound capacitor element is formed. The base material of the winding stop tape 4 is polypropylene, polyester, polyimide, polyphenylen sulfide, polyethylene naphthalate, polyether imide, etc. While the capacitance element is rotated in the winding direction, a linear heater is brought into contact with the winding stop tape on the outer peripheral part of the capacitor element, and a linear thermal fusing part is formed at a position stopping over at least the winding end part of the winding stop tape 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic capacitor in which an electrolytic material is impregnated in a capacitor element having a valve metal member on which a chemical conversion film is formed.

[0002]

2. Description of the Related Art A solid electrolytic capacitor in which a TCNQ complex salt as an electrolyte is impregnated in a capacitor element having a valve action metal member formed with a chemical conversion film is disclosed in JP-B-62-51489.
And the like.

FIG. 6 (cross-sectional view) shows an example of the configuration of the solid electrolytic capacitor according to the prior art.

In this solid electrolytic capacitor, an appropriate amount of powder of TCNQ complex salt 8 is packed in a bottomed cylindrical aluminum case 9 and heated to 250 to 350 ° C. to melt and liquefy the TCNQ complex salt. 7 soaked in T
After impregnating with the CNQ complex salt, it is quenched to solidify the TCNQ complex salt, and the opening of the case 9 is filled with an epoxy resin 10 and sealed. 6 is a lead tab terminal and 5 is a lead wire.

[0005] As shown in FIG. 5, the capacitor element 7 is formed by winding an etched aluminum foil 1 for an anode having a chemical conversion film formed thereon and an opposite cathode foil 2 via a separator paper 3.
The winding stopper tape 4 is wound around the outer periphery.
The anti-winding tape is made of polyester or the like as a base material, and has an adhesive glue applied to the winding surface and a back surface treatment material applied to the back surface.

[0006]

However, the adhesive glue of the above-mentioned wrapping tape has a strong adhesive strength to the aluminum foil and the separator paper, but has a weak adhesive strength to the back surface treatment material of the wrapping tape. A problem like this occurs.

(1) After stopping the winding, the end of the winding tape may come off due to the influence of moisture while being left indoors.

(2) After wrapping, when the capacitor element is immersed in the re-formation solution, the moisture of the re-formation solution has an adverse effect on the adhesion of the wrap-around tape, and the end-of-roll end of the wrap-around tape may come off. .

(3) After the re-chemical formation, the capacitor element is
When performing a heat treatment of heating to 300 ° C., the adhesion between the adhesive tape of the winding tape and the back surface treatment material is further reduced due to the influence of heat, and the winding end of the winding tape may come off.

If the end of the winding tape is peeled off as described above, the capacitor element cannot be completely inserted when inserted into the aluminum case, resulting in poor appearance.

The present invention solves the above-mentioned problems in an electrolytic capacitor.

[0012]

An electrolytic capacitor according to the present invention is a solid electrolytic capacitor in which an electrolytic material is impregnated in a capacitor element formed by winding an anode foil having a chemical conversion film formed thereon and an opposing cathode foil via a separator. One or more turns of a tape for winding the capacitor element were wound around the outer periphery of the capacitor element, and at least a part of the winding end of the winding tape was heat-sealed to a lower layer of the winding end of the winding tape. It is characterized by the following.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electrolytic capacitor according to a preferred embodiment of the present invention is manufactured through the following steps.

First, a high-purity aluminum foil is subjected to a chemical etching treatment to form irregularities on the surface, and then subjected to an electrochemical anodic oxidation treatment (chemical conversion treatment) to form an oxide film (chemical formation) on the irregular surface. Film).

Next, as shown in FIG. 4, the aluminum foil subjected to the chemical conversion treatment is used as an anode 1 and is wound into a cylindrical shape with a counter cathode foil 2 through a separator paper 3 made of Manila hemp or the like. The winding tape 4 is wound around the outer periphery one or more times to form a wound capacitor element as shown in FIG.

The winding tape 4 is made of polypropylene, polyester, polyimide, polyphenylene sulfide,
It has a substrate made of polyethylene naphthalate, polyetherimide, or the like, is coated with an adhesive glue on the winding surface, and is coated with a back surface treatment material on the back surface.

Next, while rotating the capacitor element in the winding direction, a linear heater is brought into contact with the winding tape on the outer periphery thereof, and as shown in FIG. A linear heat-sealed portion 49 is formed at a position straddling the end 44. When polyester is used as the base material of the anti-winding tape, the temperature of the heater for heat fusion is set to 200 to 300 ° C.

In the example shown in FIG. 1, two heat-sealed portions 9 are formed using two linear heaters over the entire circumference at a position where the width of the winding tape is divided into three equal parts. FIG.
(A) As shown in FIG.
4 may be formed only at the position straddling, or as shown in FIG. 2 (b), the linear heat fusion portion 49a is straddled diagonally across the winding end end 44 of the winding tape. The attachment portion 49b may be formed, as shown in FIG. 2C, a number of heat-sealed portions 49c may be formed within the width of the wrapping tape, or as shown in FIG. As shown, a planar heat-fused portion 49d may be formed within the width of the winding tape.

Thereafter, a re-chemical conversion treatment is performed to repair the defects and defects of the chemical conversion film generated at the time of cutting or winding the anode aluminum foil, and further, at about 200 ° C. to stabilize the chemical conversion film. Heat treatment.

On the other hand, the bottomed cylindrical aluminum case is made of T-Nbutylisoquinolinium (TCNQ) 2 or other T
Pack an appropriate amount of CNQ complex salt powder,
To melt the TCNQ complex.

Then, the capacitor element is immersed in a TCNQ complex salt melted and liquefied in the case to form a TCNQ.
After impregnation with the complex salt, the TCNQ complex salt is solidified by rapid cooling, the opening of the case is filled with an epoxy resin, and aging is performed to complete a desired electrolytic capacitor.

Here, Examples 1 and 2 in which the heat-sealing treatment was applied to the winding tape according to the present invention, and Conventional Examples 1 and 2 in which the heat-sealing treatment was not applied to the winding tape according to the prior art,
For No. 2, the rating, size, electrical characteristics (average of 50 samples) of the capacitor and the appearance failure rate (10 samples)
00) are shown in Table 1.

[0023]

[Table 1]

In Table 1, the leakage current was measured 30 seconds after the application of the rated voltage. The poor appearance was defined as the capacitor element normally inserted into the aluminum case because the end of the winding tape was peeled off. It means that it is not done.

As can be seen from Table 1, the appearance defect rate of the embodiment of the present invention is significantly lower than that of the conventional example.

In the present invention, as the electrolyte impregnated in the capacitor element, a conductive polymer such as polypyrrole, polythiophene, polyfuran, polyaniline, or a derivative thereof may be used instead of the TCNQ complex salt. An organic acid salt or the like dissolved in an organic solvent may be used.

[0027]

As described above, in the solid electrolytic capacitor according to the present invention, the appearance failure is suppressed as compared with the conventional example, and the electric characteristics are not impaired.

[Brief description of the drawings]

FIG. 1 is a perspective view of a capacitor element used in an embodiment of the present invention.

FIG. 2 is a perspective view of a capacitor element used in another embodiment of the present invention.

FIG. 3 is a perspective view of a capacitor element used in an embodiment of the present invention before a heat sealing process.

FIG. 4 is a partially exploded perspective view of a capacitor element used in the embodiment of the present invention.

FIG. 5 is a partially exploded perspective view of a capacitor element used in a conventional example.

FIG. 6 is a cross-sectional view of an electrolytic capacitor according to an embodiment of the present invention and a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anode foil 2 Cathode foil 3 Separator paper 4 Wrapping tape 44 End of winding 49 Heat fusion part 5 Lead wire 6 Lead tab terminal 7 Capacitor element 8 Electrolyte 9 Outer case 10 Sealing resin

Claims (3)

[Claims] 1. An electrolytic capacitor in which an electrolytic material is impregnated with a capacitor element formed by winding an anode foil having a chemical conversion film formed thereon and an opposite cathode foil via a separator, wherein the capacitor element is wound around an outer periphery of the capacitor element. Wrap one or more turns of the tape for stopping, at least a part of the winding end of the stopping tape,
An electrolytic capacitor characterized by being thermally fused to a lower layer of a winding end of the winding tape. 2. The electrolytic capacitor according to claim 1, wherein the base material of the winding tape is made of polypropylene, polyester, polyimide, polyphenylene sulfide, polyethylene naphthalate, or polyetherimide. 3. The electrolytic capacitor according to claim 1, wherein the electrolyte material comprises a TCNQ complex salt or a conductive polymer.