JPH06112097A - Manufacture of solid-state electrolytic capacitor - Google Patents

Abstract

PURPOSE:To obtain a method of manufacturing a solid-state electrolytic capacitor where organic semiconductor is used as solid-state electrolyte so as to almost completely prevent moisture from penetrating into the capacitor through its resin-sealed part. CONSTITUTION:A preheated capacitor element 3 is housed in a case 4 where a certain amount of organic semiconductor of TCNQ complex melted by heating is previously filled and impregnated with organic semiconductor, liquid sealing resin 6 is injected into the case 4 through an opening so as to form a convex surface protruding from the opening concerned, and thereafter the liquid sealing resin 6 is hardened to hermetically seal up the opening of the case 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a solid electrolytic capacitor using an organic semiconductor as a solid electrolyte, which has improved means for sealing the opening of a case accommodating a capacitor element.

[0002]

2. Description of the Related Art In recent years, with the sophistication of electronic information devices, there has been a demand for miniaturization and higher performance of parts. Even in electrolytic capacitors, conventional electrolytic capacitors impregnated with a driving electrolytic solution have been used. A solid electrolytic capacitor using an organic semiconductor composed of a TCNQ complex that can be miniaturized as a solid electrolyte has already been put into practical use.

Conventionally, a solid electrolytic capacitor using an organic semiconductor composed of a TCNQ complex as a solid electrolyte has a surface of an aluminum foil roughened with an etching solution to increase its surface area, and then an anode foil having an anodic oxide film formed thereon, and an aluminum foil. A spacer made of kraft paper or Manila paper is interposed between the cathode foils whose surface has been roughened with an etching solution to increase the surface area in the same manner as described above, and the anode lead terminals and cathode lead-outs are provided at any desired points on the anode foil and cathode foil. The terminal is attached and wound, and the capacitor element is preheated, and the organic semiconductor consisting of the TCNQ complex is put in advance and housed in a case that is heated and melted to impregnate the organic semiconductor into the capacitor element, followed by cooling and solidification. The case opening is then sealed with a sealing resin made of, for example, an epoxy resin.

In the solid electrolytic capacitor using the organic semiconductor made of the TCNQ complex as a solid electrolyte as described above, a sealing resin structure is used without using a rubber sealing plug as a sealing structure when a rubber sealing plug is used. , The anodic oxide film is destroyed by the stress applied to the lead-out terminal during the rubber sealing plug insertion process, but TCN as a solid electrolyte
The reason why organic semiconductors consisting of Q-complex does not have the ability to repair the anodized film unlike the driving electrolyte is that it is possible to eliminate the factor that causes the anodized film to break without stressing the lead terminals during the manufacturing process. It is based on.

However, in order to keep the sealing means by the sealing resin in the solid electrolytic capacitor having the above-mentioned structure small in size, the sealing resin injection level is controlled so that it is lower than the tip of the case opening. There is.

That is, according to the study of the present inventors, when the liquid level of the sealing resin filled is lower than the opening of the case, the liquid level of the sealing resin has a recess at the center due to the surface tension. It has been confirmed that when it is hardened by, the shrinkage acting on the surface causes a hardening shrinkage stress between the case and the sealing resin as shown by an arrow in FIG. 3, and a crack easily occurs between the case and the sealing resin.

However, when a crack is generated between the case and the sealing resin in this way, the organic semiconductor composed of the TCNQ complex as a solid electrolyte comes into direct contact with the outside air through the cracked portion, and the capacitance is reduced. And increased tan δ and other adverse effects, and the function as a capacitor deteriorates over time, resulting in poor reliability.

Therefore, it has been attempted to solve the above problems by applying a surface treatment agent to the inner surface of the case and increasing the adhesion between the case and the sealing resin. It was adversely affected and could not be a fundamental solution to the above problems.

[0009]

As described above, according to the resin sealing means of the solid electrolytic capacitor using the organic semiconductor made of the TCNQ complex as the solid electrolyte having the above-mentioned structure, the state is lower than the tip of the case opening. Since the sealing resin injection level is controlled as described above, a crack occurs between the case and the sealing resin due to contraction of the injected sealing resin liquid during the curing process, and the organic semiconductor directly contacts the outside air through this cracked portion. Therefore, the capacitor characteristics deteriorated over time, and the reliability was poor.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and by improving the resin sealing means for sealing the opening of the case, a solid electrolyte of high reliability with little deterioration of the capacitor characteristics can be obtained. It is an object of the present invention to provide a method for manufacturing a solid electrolytic capacitor, which can obtain a solid electrolytic capacitor using an organic semiconductor composed of a TCNQ complex.

[0011]

According to the method of manufacturing a solid electrolytic capacitor of the present invention, a spacer is interposed between an anode foil and a cathode foil made of a valve metal having lead-out terminals attached at arbitrary places housed in a case. The organic semiconductor is impregnated into the wound capacitor element, and then the case opening is filled with a liquid sealing resin, and in the method for producing a solid electrolytic capacitor obtained by curing the liquid sealing resin, the liquid sealing resin surface is It is characterized in that it is hardened into a convex shape protruding from the tip of the case opening.

[0012]

According to the above construction, the liquid sealing resin surface to be filled in the case opening is cured in a convex shape protruding from the tip of the case opening, so that it is generated on the surface during curing. Since the combined force of the curing shrinkage stress is smaller than that in the case of the concave shape, the force that the inner surface of the case opening and the sealing resin tend to separate can be correspondingly reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. That is, as shown in FIG. 1, first, the surface of the aluminum foil is roughened with an etching solution to increase the surface area, and then the anode foil on which the anodized film is formed and the surface of the aluminum foil are roughened with the same etching solution as above to reduce the surface area. A spacer made of kraft paper or manila paper was interposed between the enlarged cathode foils, and anode lead terminals 1 and cathode lead terminals 2 were attached and wound around arbitrary portions of the anode foil and the cathode foil on the way. In a preheated state, the capacitor element 3 is housed in a case 4 made of, for example, aluminum in which a predetermined amount of a heat-melted organic semiconductor made of a TCNQ complex is put, and the organic semiconductor is impregnated in the capacitor element 3. The remaining organic semiconductor melt that has been solidified by cooling and not impregnated is placed on the bottom surface of the case 4 as the solidified organic semiconductor 5 and the opening of the case 4 described above. , A liquid sealing resin 6 made of, for example, an epoxy resin is injected so as to form a convex surface protruding from the tip of the opening of the case 4, and then the liquid sealing resin 6 is cured to seal the opening of the case 4. It is a thing.

According to the method of manufacturing the solid electrolytic capacitor having the above-mentioned structure, the liquid sealing resin 6 is injected into the opening of the case 4 in the means for sealing the opening of the case 4 so as to project from the tip of the opening of the case 4. Since the liquid sealing resin 6 is cured after that, the curing shrinkage stress generated in the curing process of the liquid sealing resin 6 is as shown by the arrow in FIG. Since the same force as in the other directions also acts on the convex shaped surface of, the force of peeling from the inner surface of the case 4 becomes smaller accordingly.
The occurrence of cracks between the inner surface of the case 4 and the sealing resin is extremely reduced, and the possibility of contact between the organic semiconductor and the outside air caused by the cracks is drastically reduced, resulting in a decrease in capacitance and ta.
The factor of increasing nδ is greatly improved, and there is an advantage that a solid electrolytic capacitor using an organic semiconductor made of a TCNQ complex as a highly reliable solid electrolyte can be obtained.

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

That is, the capacitor element manufactured by the means described in the above embodiment is housed in a heated state in a case in which an organic semiconductor melt composed of a TCNQ complex of Nn-butylisoquinolinium is housed. After impregnation, the organic semiconductor melt is cooled and solidified, and then epoxy resin is injected into the voids in the case from the case opening so that the surface state is a convex surface protruding from the tip of the case opening. Same as Example A obtained by curing the rear epoxy resin, and the same as Example A except that the surface state of the epoxy resin from the case opening to the void in the case is lower than the tip of the case opening. 1 with conventional example B consisting of means
As a result of examining the rate of change in capacitance with respect to time when a rated voltage (16 V) was applied in a constant temperature bath of 05 ° C, the result was as shown in Fig. 4, except that a transparent epoxy resin was used as the sealing resin. , Example A manufactured by the same means as above
As a result of examining the state of penetration into the interior using the permeable penetrant agent in Conventional Example B, the results are shown in Table 1.

The samples in FIG. 4 and Table 1 are 50 in each of Example A and Conventional Example B, and the numerical values in FIG. 4 are average values.

[0018]

[Table 1]

As is clear from Table 1 and FIG. 4, the conventional example B has a remarkable water permeability, and therefore the rate of change in capacitance with time increases with time, which is not practical. The water permeability of Example A is also small, and the capacitance change is -2 even after 1000 hours.
%, The excellent sealing property was demonstrated.

[0020]

According to the present invention, it is possible to provide a solid electrolytic capacitor which uses a highly reliable organic semiconductor as a solid electrolyte which has good sealing property and does not deteriorate in various characteristics even after long-term use. A method of manufacturing a capacitor can be obtained.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram showing a state of curing shrinkage stress in a sealing resin curing process of the solid electrolytic capacitor shown in FIG.

FIG. 3 is an explanatory view showing a state of curing shrinkage stress in a sealing resin curing process of a solid electrolytic capacitor according to a conventional example.

FIG. 4 is a characteristic curve diagram showing a capacitance change rate with respect to time.

[Explanation of symbols]

 1 Anode Lead Terminal 2 Cathode Lead Terminal 3 Capacitor Element 4 Case 5 Solid State Organic Semiconductor 6 Liquid Sealing Resin

Claims (1)

[Claims] 1. A capacitor element wound by interposing a spacer between an anode foil and a cathode foil made of a valve metal having a lead terminal attached to an arbitrary position housed in a case is impregnated with an organic semiconductor, and thereafter. A method of manufacturing a solid electrolytic capacitor, comprising filling the case opening with a liquid sealing resin and curing the liquid sealing resin, characterized in that the liquid sealing resin surface is made into a convex shape and cured. Production method.