JP3152572B2 - Method for manufacturing solid electrolytic capacitor - 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.

[0002]

2. Description of the Related Art A solid electrolytic capacitor using a TCNQ complex salt, which is a kind of organic semiconductor, as an electrolyte is disclosed in
-52939. Where TCNQ
Means 7,7,8,8-tetracyanoquinodimethane.

[0003] The solid electrolytic capacitor according to the prior art is manufactured through the following steps.

[0004] First, as shown in FIG. 5, a surface of an etched aluminum foil 1 for an anode is subjected to a chemical conversion treatment to form a dielectric film, and the anode foil 1 is separated from a cathode foil 2 and a separator.
It is wound together with the tab paper 3 to form the capacitor element 7.
In FIG. 5, reference numeral 4 denotes a winding tape, reference numerals 51 and 52 denote anode and cathode lead terminals, and reference numerals 61 and 62 denote lead bosses. Next, an appropriate amount of the powder of the TCNQ complex salt is packed in a bottomed cylindrical aluminum case, which is heated to melt the TCNQ complex salt. And a TCNQ in which the capacitor element is melted and liquefied from the opening of the aluminum case.
Inserted and immersed in a complex salt, impregnated the TCNQ complex salt as an electrolyte inside the capacitor element, immediately quenched, and
The complex is allowed to solidify. Finally, as shown in FIG. 6, the opening of the aluminum case 90 is sealed with an epoxy resin 8.

[0005]

The solid electrolytic capacitor according to the prior art described above is one in which the opening of the aluminum case is sealed with epoxy resin, so that it has excellent temperature characteristics, high temperature load characteristics, moisture resistance characteristics and the like. Although it is highly reliable and excellent in environmental resistance, it has the following disadvantages.

That is, after immersing the capacitor element in the molten TCNQ complex salt, in the process of cooling and solidifying the TCNQ complex salt, the capacitor element becomes an aluminum casing.
7B, the positions of the lead terminals 51 and 52 may be shifted as shown in FIGS. 7B and 7C. FIG. 7 is a top plan view of the solid electrolytic capacitor, and FIG.
Examples where the positions of 1, 52 are normal, (b) and (c) show that the capacitor element is fixed to the end inside the case 90 and the lead terminal 5
The example where the positions of 1 and 52 are abnormal is shown.

Further, in the step of sealing the opening of the aluminum case with epoxy resin, there is a problem that the height of the rise of the epoxy resin from the opening end of the case is not constant.

[0008] The above-mentioned problems not only lead to dimensional defects as a product as they are, but also in the case where processing such as molding of lead terminals after curing of an epoxy resin for surface mounting is particularly required. A dimensional design that can relatively absorb dimensional errors is required, which results in a large size for surface mounting and an increase in product cost.

On the other hand, if the rubber sealing method commonly used for electrolyte type capacitors is simply diverted as the sealing method for the solid electrolytic capacitor, the following problems occur.

In other words, when the sealing rubber is attached to the lead terminal portion of the capacitor element and then impregnated with the TCNQ complex salt, the rubber may expand and deteriorate due to the heating in the impregnation step and may not enter the aluminum case. In order to avoid the problem, rubber having excellent heat resistance is required, which increases the cost.

When the sealing element is to be mounted after the capacitor element has been impregnated with the TCNQ complex salt, the rubber must be inserted through the opening of the aluminum case and the lead terminal of the capacitor element must be passed through the rubber. In addition, not only workability is poor, but also poor appearance due to incomplete mounting occurs.

The present invention has been made to solve the above-mentioned problems relating to a solid electrolytic capacitor.

[0013]

The method of manufacturing a solid electrolytic capacitor according to the present invention comprises inserting and dipping a capacitor element into an electrolyte material such as a TCNQ complex salt melted and liquefied in a first case. A step of impregnating the inside of the capacitor element with the electrolyte material, a step of cooling and solidifying the electrolyte material inside the capacitor element by extracting the capacitor element from the first case, and a lead terminal of the capacitor element A step of mounting an elastic member for sealing the case at the root of the case, and a step of housing the capacitor element with the sealing member in a second case.

[0014]

According to the method of the present invention, an elastic member for sealing a case is attached to the root of the lead terminal of the capacitor element in a state where the capacitor element impregnated with the electrolyte material is pulled out from the first case. At this time, the displacement of the lead terminal is corrected, and the capacitor element with the sealing member is accurately stored in the second case.

Further, since the epoxy resin is not used for sealing the case, not only the problem of swelling of the epoxy resin in the sealing portion is avoided, but also the management of the mixing ratio of the epoxy resin, the pot life, the viscosity, etc. is unnecessary. Become.

[0016]

Embodiments of the present invention will be described below.

In the manufacturing method of the solid electrolytic capacitor according to the embodiment of the present invention, first, as shown in FIG. 1 is wound together with the cathode foil 2 and the separator paper 3 to form the capacitor element 7. On the other hand, an appropriate amount of TCNQ complex salt powder is packed in a bottomed first aluminum case, which is heated to melt the TCNQ complex salt.

Then, as shown in FIG. 2, the capacitor element 7 is inserted and immersed in the molten TCNQ complex salt from the opening of the first aluminum case 9, and the TCNQ complex salt as an electrolyte is placed inside the capacitor element. Immediately after the impregnation, the capacitor element is pulled out of the first aluminum case, and the TCNQ complex salt is cooled and solidified.

Thereafter, as shown in FIG. 1, the lead terminals 51 and 52 of the capacitor element 7 are inserted through the holes of the case sealing rubber 11, and the sealing rubber 11 is inserted into the lead terminals 51 and 52. Lead bosses 61, 62 at the root
And the capacitor element with a rubber for sealing is housed in a second aluminum case 10 having substantially the same diameter as the first aluminum case, and the side surface near the opening of the second aluminum case is removed. The opening of the case 10 is sealed by curling and tightening the sealing rubber 11.

Further, in the case of a vertical chip type for surface mounting, as shown in FIG. 3, lead terminals 51 and 52 are inserted into holes of the plastic pedestal 12, penetrated, bent, and Fix the capacitor body to the base.

In the case of a horizontal chip type, as shown in FIG. 4, after the lead terminals 51 and 52 are bent and formed into a predetermined shape, the capacitor body is hollowed out of the external plastic case 13. Store and fix in the section.

Table 1 shows the dimensions of the second aluminum case, the sealing rubber and the finished product in various vertical chip type solid electrolytic capacitors manufactured according to the above embodiment.

[0023]

[Table 1]

[0024]

According to the present invention, a dimensional accuracy of a lead terminal portion and a case sealing portion of a solid electrolytic capacitor is improved, and a small solid electrolytic capacitor suitable for surface mounting or the like is provided.

In a conventional solid electrolytic capacitor using an epoxy resin as a sealing material, when a completed product is subjected to a soldering heat test, the epoxy resin expands and contracts due to solder heat, cracks are generated in the capacitor element, and leakage occurs. Current (L
Although C) sometimes increased, in the solid electrolytic capacitor according to the present invention, since the epoxy resin was not used, the capacitor element was not damaged by solder heat, and the solder heat resistance was also improved.

The solid electrolytic capacitor according to the embodiment of the present invention using rubber sealing and the conventional solid electrolytic capacitor using epoxy resin sealing are:
Table 2 shows the results of a solder heat test at 230 ° C. × 10 seconds after preheating at 50 ° C. × 120 seconds.

[0027]

[Table 2]

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view for explaining an electrolyte impregnation step in an embodiment of the present invention.

FIG. 3 is a side view of a vertical chip capacitor.

FIG. 4 is a perspective view of a horizontal chip capacitor.

FIG. 5 is a partially exploded perspective view of a capacitor element.

FIG. 6 is a sectional view of a conventional solid electrolytic capacitor.

FIGS. 7A and 7B are top plan views of a conventional solid electrolytic capacitor, in which FIG. 7A shows a non-defective product and FIGS.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anode foil 2 Cathode foil 3 Separator paper 5 Lead terminal 6 Lead boss 7 Capacitor element 9 First case 10 Second case 11 Elastic member for sealing

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-60-167413 (JP, A) JP-A-62-185308 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01G 9/00 H01G 9/028

Claims (3)

(57) [Claims] A step of inserting and dipping a capacitor element into an electrolyte material melted and liquefied in a first case to impregnate the electrolyte element into the interior of the capacitor element; Removing the electrolyte material inside the capacitor element from the case and cooling and solidifying the electrolyte material inside the capacitor element; and housing the capacitor element in a second case. The first case and the second case Wherein the case is a cylindrical body having substantially the same diameter. 2. After cooling and solidifying the electrolyte material impregnated in the capacitor element, a sealing member for sealing a case is attached to a root portion of a lead terminal of the capacitor element. 2. The method for manufacturing a solid electrolytic capacitor according to claim 1, further comprising a step of housing the solid electrolytic capacitor in a second case. 3. The method according to claim 1, wherein the electrolyte material is a TCNQ complex salt.