JPH07302736A - Solid electrolytic capacitor and method of manufacturing the same - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To solve various problems related to the method of sealing the outer case of a solid electrolytic capacitor. In the solid electrolytic capacitor according to the present invention, a capacitor element impregnated with a solid electrolyte is housed in a first case 4, the first case is housed in a second case 5, and an opening of the second case is formed. The portion is sealed by an elastic member 7 such as rubber, and the lead terminal 2 of the capacitor element is penetrated through the elastic sealing member and pulled out to the outside.

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 type of organic semiconductor, as an electrolyte is disclosed in Japanese Patent Publication No.
It is disclosed in Japanese Patent Publication No. 52939. TCNQ here
Means 7,7,8,8-tetracyanoquinodimethane.

In the above-mentioned prior art, TCNQ complex salt powder is loaded into an exterior case having excellent thermal conductivity, and this is heated to 250 to 300 ° C. and preheated to the place where the TCNQ complex salt is melted and liquefied. After immersing the stored capacitor element, it is rapidly cooled to solidify the TCNQ complex salt, the opening of the case is filled with an epoxy resin, and the temperature is raised to 85 to 105 ° C. to cure the epoxy resin. The outer surface of the case is covered with a display tube to manufacture a solid electrolytic capacitor having a cross-sectional structure as shown in FIG. In FIG. 5, 1 is a capacitor element, 2 is a lead terminal connected to the anode and cathode of the capacitor element, 3 is a TCNQ complex salt, 4
Reference numeral 5 is an exterior case, 6 is a display tube, and 77 is an epoxy resin.

[0004]

However, when the epoxy resin is used as the sealing material of the case, the appearance of the resin such as the adhesion of the resin to the lead wire of the capacitor element and the crack of the display tube due to the burr of the resin surface occurs. .

Further, it takes a long time to cure an epoxy resin, and it is complicated to manage the resin composition, viscosity, pot life, curing conditions, etc., resulting in increased man-hours and cost.

Furthermore, when this capacitor is mounted on a printed circuit board or the like, the epoxy resin expands and contracts due to the solder heat, and cracks occur in the capacitor element,
This causes an increase in leakage current.

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

That is, electrical characteristics equivalent to those of resin-sealed products,
In order to maintain reliability, the size of the sealing rubber must be increased, and therefore the size of the exterior case must be increased, which increases the amount of TCNQ complex salt powder loaded in the case and increases the material cost.

When the sealing rubber is attached to the lead terminal portion of the capacitor element and then the solid electrolyte is impregnated, there is a risk that the rubber expands and deteriorates due to the heating in the impregnation step and cannot enter the exterior case. In order to avoid this problem, a rubber having excellent heat resistance is required, resulting in high cost.

Further, when the sealing rubber is mounted after the capacitor element is impregnated with the TCNQ complex salt, the rubber must be inserted through the opening of the case and at the same time, the lead terminal of the capacitor element must be penetrated through the rubber. Not only the workability is poor, but the appearance is poor due to incomplete mounting.

The present invention solves the above-mentioned problems related to the method of sealing a solid electrolytic capacitor.

[0012]

In a solid electrolytic capacitor according to the present invention, a capacitor element impregnated with a solid electrolyte is housed in a first case, the first case is housed in a second case, and the second case is The opening of the case is sealed with an elastic member such as rubber, and the lead terminals of the capacitor element are pulled out to the outside through the elastic sealing member. , A capacitor element impregnated with a solid electrolyte is housed in a first case, and an elastic member is attached to a lead terminal portion of the capacitor element,
The first case is housed in the second case, and the opening of the second case is sealed by the elastic member.

[0013]

According to the present invention, since no epoxy resin is used as the sealing material, the appearance of the resin such as the adhesion of the resin to the lead wire of the capacitor element and the crack of the display tube due to the burr on the resin surface does not occur. Further, it is not necessary to manage the resin composition, viscosity, pot life, curing conditions, and the like.

On the other hand, since the capacitor element impregnated with the solid electrolyte is housed in the first case, which is smaller than the second case, the amount of the solid electrolyte can be reduced.
Since a large sealing member is arranged in the opening of the second case, which is larger than the first case, electrical characteristics and reliability are secured.

Further, since the sealing member is mounted after the capacitor element is impregnated with the solid electrolyte, there is no fear of thermal deterioration of the sealing member in the impregnation step, and after mounting the sealing member on the lead terminal of the capacitor element. Since it is housed in the second case, workability is excellent, and appearance defects due to imperfect mounting are less likely to occur.

Further, even when the sealing member expands or contracts due to the heat of solder, the elastic sealing member absorbs the stress, so that the generation of cracks in the capacitor element is suppressed and the leakage current defect is reduced.

[0017]

EXAMPLES Examples of the present invention will be described below.

The solid electrolytic capacitor according to the present invention has a sectional structure as shown in FIG. 1, for example. In this solid electrolytic capacitor, a capacitor element 1 impregnated with a solid electrolyte 3 such as TCNQ complex salt is housed in a first case 4, and
Is housed in the second case 5, the opening of the second case is sealed by a sealing member 7 made of an elastic material such as rubber, and the lead terminal 2 of the capacitor element penetrates the elastic sealing member. It is characterized by being pulled out to the outside.

The solid electrolytic capacitor shown in FIG. 1 is manufactured through the following steps.

First, the powder of the solid electrolyte 3 such as TCNQ complex salt is loaded into the first case 4 made of aluminum in the shape of a cylinder with a bottom and heated to 250 to 300 ° C. to melt and liquefy the TCNQ complex salt and preheat it. The capacitor element 1 was immersed in a melted and liquefied TCNQ complex salt to impregnate the capacitor element with the TCNQ complex salt, and immediately cooled to solidify the TCNQ complex salt. FIG. 2 shows a cross section of a semi-finished solid electrolytic capacitor obtained through the steps up to here.

Here, as a typical constitution of the capacitor element 1, a surface of an etched aluminum foil for an anode is subjected to a chemical conversion treatment to form a dielectric oxide film, which is wound together with a cathode foil through a separator paper. There are things. A lead terminal 2 is connected to the anode foil and the cathode foil.

Next, as shown in FIG. 3, a sealing member 7 made of an elastic material such as rubber is attached to the lead terminal portion 2 of the capacitor element, and is slightly larger than the first case 4 as shown in FIG. Stored in the second case 5.

Finally, the opening end side of the second case 5 is curled and laterally squeezed, and the display tube 6 is covered to complete the solid electrolytic capacitor as shown in FIG.

Table 1 shows dimensional examples (cylindrical diameter φ × length L, unit: mm) of the first case 4, the second case 5, and the elastic sealing member 7 according to the rating of the capacitor.

[0025]

[Table 1]

[0026]

According to the present invention, the problems of the conventional resin-sealed solid electrolytic capacitor, that is, the problems such as the adhesion of the resin to the lead wire of the capacitor element and the cracking of the display tube due to the burr on the resin surface are avoided. can do. Further, management of resin blending, viscosity, pot life, curing conditions, etc. is unnecessary, and the number of manufacturing steps is reduced.

On the other hand, there is a problem that the practical use of the solid electrolytic capacitor with the rubber sealing is impeded, that is, the amount of the solid electrolyte is large in order to secure the same electrical characteristics and reliability as those of the solid electrolytic capacitor with the resin sealing. However, the problems of thermal deterioration of the rubber sealing member, workability when mounting the rubber sealing member, and poor appearance due to incomplete mounting are eliminated.

Further, with respect to the problem that the sealing member expands and contracts due to the heat of solder, the elastic sealing member absorbs the stress, so that the generation of cracks in the capacitor element is suppressed and the leakage current defect is reduced. To do. The results of the solder heat resistance test are shown in Table 2.

[0029]

[Table 2]

In the solder heat resistance test, a sample capacitor was mounted in close contact with a glass epoxy substrate having a thickness of 0.6 mm, and 15
It is preheated at 0 ° C. for 120 seconds and then immersed in a solder bath at 260 ° C. for 10 seconds. Examples shown in Table 2 are solid electrolytic capacitors with rubber sealing according to the present invention, and comparative examples are resin sealing according to prior art. The present invention relates to solid electrolytic capacitors. In the comparative example, a small leakage current defect occurs, but in the inventive examples, no leakage current defect occurs.

[Brief description of 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 (No. 1) of a semi-finished solid electrolytic capacitor for explaining a method for manufacturing a solid electrolytic capacitor according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view (part 2) of a semi-finished solid electrolytic capacitor for explaining a method for manufacturing a solid electrolytic capacitor according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view (3) of a semi-finished solid electrolytic capacitor for explaining a method for manufacturing a solid electrolytic capacitor according to an example of the present invention.

FIG. 5 is a cross-sectional view of a conventional solid electrolytic capacitor.

[Explanation of symbols]

 1 Capacitor Element 2 Lead Terminal 3 Solid Electrolyte 4 First Case 5 Second Case 6 Display Tube 7 Elastic Sealing Member

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Claims (3)

[Claims] 1. A capacitor element impregnated with a solid electrolyte is housed in a first case, the first case is housed in a second case, and the opening of the second case is sealed by an elastic member. A solid electrolytic capacitor, wherein a lead terminal of the capacitor element penetrates the elastic sealing member and is drawn to the outside. 2. The solid electrolytic capacitor according to claim 1, wherein the elastic sealing member is made of rubber. 3. A capacitor element impregnated with a solid electrolyte is housed in a first case, an elastic member is attached to a lead terminal portion of the capacitor element, and the first case is housed in a second case. A method for manufacturing a solid electrolytic capacitor, characterized in that the opening of the second case is sealed with the elastic member.