JPS63146429A - Electrolytic capacitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electrolytic capacitor used in various electronic devices.

Conventionally, as shown in Figure 6, this type of electrolytic capacitor has been made by roughening a valve metal foil and then forming a dielectric film by anodizing it as an anode foil, and a cathode foil as a counter electrode. are wound through a separator to make a capacitor element 1, and the capacitor element 1 is impregnated with a driving electrolyte and stored in a metal case 2. A rivet 5 connected to a lead wire 4 to be drawn out passes through the sealing body 3, which is formed by pasting an elastic body 3b on a hard insulator 3a, to prevent the driving electrolyte inside from evaporating to dryness. It is structured like this.

In such electrolytic capacitors, the surface area of the electrode is expanded, the dielectric film is extremely thin, the dielectric constant is high, and the driving electrolyte penetrates into the intricately inserted electrode part and adheres closely to the cathode body. By working as a capacitor, it is possible to obtain a capacitor that is smaller and has a larger capacity than other types of capacitors. In addition, since the drive electrolyte is contained inside, it easily evaporates at high temperatures and solidifies at low temperatures. The properties depend on the driving electrolyte. On the other hand, what determines the life of an electrolytic capacitor is the sealing body that prevents the internal driving electrolyte from evaporating.The material and structure of this sealing body 3 determine the reactivity, solubility, and Evaporation rate etc. are determined and subject to restrictions.

In other words, the characteristics of the driving electrolyte are determined by the sealing body 3, and furthermore, the sealing body 3
Therefore, it is no exaggeration to say that the sealing body 3 determines the performance of the capacitor.

Problems to be Solved by the Invention However, the conventional electrolytic capacitor sealing body 3 as described above
In this structure, when the electrolytic capacitor is mounted on a printed circuit board and cleaned with a halogenated organic solvent to remove dirt such as fluff, the rubber etc. that is part of the sealing body 3 of the electrolytic capacitor is cleaned. When a halogen-based organic solvent or the like comes into contact with the elastic body 3b, it swells and enters the inside of the electrolytic capacitor over time, corroding the capacitor element 1, internal lead wire 4, etc., and damaging the electrical properties of the electrolytic capacitor. Significantly deteriorate properties. Moreover, the driving electrolyte and the like inside the electrolytic capacitor evaporate to the outside through the elastic body 3b, such as rubber, formed in the sealing body 3, significantly shortening the life of the electrolytic capacitor. Moreover, from FIG. 6, the elastic body 3 of the sealing body sealed to the opening of the metal case 2 by drawing or curling is
Due to variations in the curling process, the processed part is cut, and the internal driving electrolyte etc. evaporates from the cut part to the outside, reducing the service life.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an electrolytic capacitor that prevents halogen-based organic solvents from entering the interior and prevents driving electrolyte from evaporating to the outside, thereby improving electrical characteristics and service life. be.

Means for Solving the Problems In order to solve these problems, the present invention has a recess on the periphery of the top surface and around the lead pull-out part, and the recess on the periphery is connected to the recess around the lead pull-out part. Harder with deeper depth!
The insulating plate and an elastic body disposed on the upper surface of the hard insulating plate so as to be embedded in the recess constitute a sealing body, and the opening of the case is sealed by the sealing body.

With this structure, when the open end of the metal case of an electrolytic capacitor is curled, the elastic body is pressed into the recess by the case edge, and there is no place for the elastic body to escape, resulting in a strong seal. This makes it possible to prevent evaporation of the electrolytic solution and to prevent halogenated organic solvents from entering the inside of the capacitor.

Embodiment Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings. In Figures 1 to 3, reference numeral 6 denotes an anode foil made by roughening a valve metal foil such as aluminum and forming a dielectric film by anodizing the anode foil, and a separator between the anode foil and the counter cathode foil. This capacitor element 6 is impregnated with a driving electrolyte and housed in a metal case 7 made of aluminum or the like. A part 8 of the beam is pulled out from the capacitor element 6, and a lead is attached to the lower end of a rivet 10 that is inserted into a sealing body 9 sealed by drawing and curling at the opening of the metal case 7. 8 is connected, and a lug terminal 11 is connected to the upper part of the rivet IO.

The sealing body 9 includes a sealing body 9a formed by molding a hard insulator such as phenol resin, and a sealing body 9a formed by molding a hard insulator such as phenol resin.
Recesses 9b and 9b' are formed on the upper surface so as to be continuous with the peripheral edge and the area where the rivet 10 penetrates, and the recess 9b in the peripheral edge is similar to the recess in the area where the electrode rivet penetrates. The recesses 9b and 9b' are approximately twice as deep as the recesses 9b', and an elastic body 9c made of rubber is fitted flush with the upper surface of the sealing body 9a. The surface area of the elastic body 9c is set to be 40% or less of the surface area of the sealing body 9, and the liquid elastic body is poured through one gate while the sealing body 9a is placed in the molding die. Molded.

As shown in Figure 4, if the surface area of the elastic body 9C exceeds 40%, the halogen-based organic solvent that is used to clean the electrolytic capacitor after mounting it on a printed circuit board to remove stains such as flux will enter the electrolytic capacitor. .

increases significantly, corrodes the capacitor element 6 and leads 8, and significantly deteriorates the electrical characteristics.

Therefore, the surface area of the elastic body 9C with respect to the sealing body 9 is 40
It is important to keep it below %.

Furthermore, the elastic body 9C has a recess 9b in the electrode rivet through hole.
' Since the depth of the concave portion 9b at the peripheral edge is approximately twice as deep, the elastic body 9C is formed thicker at the peripheral edge, and the opening of the metal case is drawn as shown in Fig. 1. This prevents the elastic body from being cut due to wobbling or curling. Furthermore, since the elastic body 9C is fitted into the recessed portion of the peripheral edge, there is no place for the elastic body to escape when the curling process is performed, and a strong airtight seal can be achieved.

Furthermore, when considering the evaporation of the driving electrolyte in the electrolytic capacitor with the above structure and the electrolytic capacitor with the conventional structure, as shown in FIG. As a result, the weight can be reduced by about half, resulting in a longer life.

Effects of the Invention As described above, the electrolytic capacitor of the present invention is composed of a hard insulator and an elastic body, and the main body of the sealing body is made of a hard rim. There is no warpage, and a strong airtight seal is possible. Furthermore, when cleaning the solder flux, the intrusion of halogen-containing 81 solvents into the inside can be suppressed because the thickness of the elastic body at the periphery is approximately twice as thick, and the surface area of the elastic body is less than 40%. It has great industrial value, as it prevents corrosion of capacitor elements and leads, stabilizes characteristics, and reduces evaporation of driving electrolyte, extending life. It is.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional front view of essential parts showing an embodiment of the electrolytic capacitor of the present invention, Fig. 2 is a perspective view of a sealing body used in the capacitor, and Fig. 3 a and b are A-A in Fig. 2. , BB' is a cross-sectional view taken along line B-B', Figure 4 is a characteristic diagram showing the relationship between the surface area of the elastic body of the sealing body and the amount of solvent intrusion, and Figure 5 is a diagram showing the relationship between the inventive and conventional electrolytic capacitors for driving. A characteristic diagram showing the weight reduction of the electrolytic solution, and Fig. 6 is a cross-sectional front view of the main parts of a conventional electrolytic capacitor. 6...Capacitor element, 7...Metal case, 8... ...Reed, 9... Sealing body,
9a... Sealing body, 9b, 9b"...
- Recess, 9C...Elastic body, 10...Rivet, 11...Lug terminal. Name of agent: Patent attorney Toshio Nakao and one other person Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] (1) A capacitor element made by winding an anode foil and a cathode foil with a separator in between, impregnated with a driving electrolyte, is housed in a case, and a sealing body is sealed in the opening of the case. , a hard insulating plate having a recess around the peripheral edge of the upper surface and around the lead pull-out part, the recess in the peripheral edge being deeper than the recess around the lead pull-out part, and a hard insulating plate embedded in the recess. An electrolytic capacitor consisting of a sealing body and an elastic body placed on the top surface of the electrolytic capacitor.