JP2548221B2 - Electrolytic capacitor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic capacitor used for various electronic devices and the like.

2. Description of the Related Art Conventionally, in this type of electrolytic capacitor, as shown in FIG. 6, a valve action metal foil is roughened, and then a dielectric film is formed by anodic oxidation to form an anode foil, and a cathode foil opposite to that is formed. Is wound through a separator to form a capacitor element 1
The capacitor element 1 is impregnated with the driving electrolytic solution and housed in the metal case 2, and the rivet 5 connected to the lead wire 4 drawn from the capacitor element 1 is penetrated through the opening of the case 2. An elastic body on the hard insulator 3a
The sealing body 3 formed by pasting 3b is sealed so that the driving electrolyte solution inside does not evaporate to dryness.

In such an electrolytic capacitor, the surface area of the electrode is enlarged, the dielectric film is extremely thin,
Due to the high dielectric constant, the driving electrolytic solution entering and adhering to the complicatedly inserted electrode body, and acting as a cathode body, a small-sized and large-capacity capacitor can be obtained as compared with other types of capacitors. Also, since it contains a driving electrolyte, it easily evaporates at high temperatures and solidifies at low temperatures.
The performance of the capacitor depends on the driving electrolytic solution, such that the operability of the capacitor is significantly poor in the evaporated or solidified state. On the other hand, the life of the electrolytic capacitor is determined by the sealing body that prevents the evaporation of the driving electrolyte solution inside, and the material and structure of this sealing body 3 makes it possible to react with the constituent materials of the driving electrolyte solution, the reactivity, the solubility, and the evaporation. The speed etc. is decided and restricted.

That is, since the characteristics of the driving electrolytic solution are determined by the sealing body 3, and further the sealing body 3 determines the maximum operating temperature of the capacitor, it is an exaggeration to say that it is the sealing body 3 that determines the performance of the capacitor. is not.

Problems to be Solved by the Invention However, in the structure of the sealing body 3 of the conventional electrolytic capacitor as described above, in order to remove stains such as flux when mounted on a printed circuit board or the like, a halogen thread organic solvent or the like is used. When washed, the halogen thread organic solvent or the like comes into contact with the elastic body 3b such as rubber, which is a part of the sealing body 3 of the electrolytic capacitor, and swells and infiltrates into the electrolytic capacitor over time, Corrosion of the capacitor element 1 and the internal lead wires 4 and the like significantly deteriorates the electrical characteristics of the electrolytic capacitor. In addition, the driving electrolytic solution inside the electrolytic capacitor passes through the elastic body 3b such as rubber formed in the sealing body 3,
It evaporates to the outside and significantly shortens the life of the electrolytic capacitor. Further, as shown in FIG. 6, the elastic body 3 of the sealing body which is sealed in the opening of the metal case 2 by the drawing process or the curling process is cut at the processed part due to the variation of the drawing process or the curling process of the metal case 2, and is cut. The driving electrolyte solution and the like inside the part evaporates to the outside and shortens the life. Therefore, in order to strengthen the curling process, it has been considered that a recess is provided in the peripheral portion of the upper surface of the hard insulator and an elastic body is fitted in the recess to perform the curling process. However, when such a concave portion is provided and curled, cracks are generated from the etched portion in the concave portion.

The present invention prevents the cracking of such a hard insulating plate, prevents the halogen thread organic solvent from entering the inside, and prevents the driving electrolyte from evaporating to the outside to improve the electrical characteristics and the life. It provides a capacitor.

Means for Solving the Problems In order to solve such a problem, the present invention provides a recess in the peripheral portion of the upper surface and the periphery of the lead lead-out portion, and the recess of the peripheral portion is deeper than the periphery of the lead lead-out portion. And a hard insulating plate in which a convex portion is provided in the peripheral portion of the lower surface in the vicinity of the inner edge portion of the concave portion of the peripheral portion of the upper surface, and the concave portion is embedded in the upper surface of the hard insulating plate. The opening of the metal case is sealed by a sealing body composed of the elastic body provided.

With such a configuration, when the open end of the metal case of the electrolytic capacitor is curled, the elastic body is pressed by the case end to be pushed into the recess from the elastic body, so that there is no escape area for the elastic body and a strong sealing is achieved. In addition, it is possible to prevent the evaporation for electrolysis and to prevent the permeation of halogen-based organic solvent into the capacitor because there is a protrusion on the inner edge of the concave part of the peripheral edge. it can.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings. In FIGS. 1 to 5, 6 is a valve-action metal foil made of aluminum or the like, which is roughened, and then formed with a dielectric film by anodic oxidation to be an anode foil, and a cathode foil opposite to this is a separator. The capacitor element 6 is wound around the capacitor element 6. The capacitor element 6 is impregnated with a driving electrolytic solution and is housed in a metal case 7 such as aluminum. Further, the lead 8 is drawn out from the capacitor element 6, and the lead 8 is connected to the lower end of the rivet 10 which is incorporated so as to penetrate the opening 9 of the metal case 7 and which is sealed by the curling process. The lug terminal 11 is coupled to the upper portion of the rivet 10.

As shown in FIGS. 2 and 3, the sealing body 9 has a sealing body 9a formed by molding a hard insulating material such as phenol resin, and a peripheral portion on the upper surface of the sealing body 9a. Recesses 9b, 9b 'are formed so as to be continuous with the periphery at the penetrating portion of the rivet 10, and the recess 9b at the peripheral edge is
It is formed with a depth of about twice as deep as the recess 9b 'of the penetrating portion of the electrode rivet, and rubber or the like is formed in these 9b, 9b'.
The elastic body 9c is fitted so as to be 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 3, and the sealing body main body 9a
Is set in a molding die, and a liquid elastic body is poured from one gate to be molded.

If the surface area of this elastic body 9c exceeds 40% as shown in Fig. 4, the amount of halogen-based organic solvent that is mounted on a printed circuit board and washed to remove dirt such as flux penetrates into the electrolytic capacitor. Significantly increases, corrodes the capacitor element 6 and the leads 8, and significantly deteriorates electrical characteristics. Therefore, it is important that the surface area of the elastic body 9c with respect to the sealing body 9 is 40% or less.

Further, the elastic body 9c is a recess 9b 'in the through hole of the electrode rivet.
And the concave portion 9b at the peripheral portion are different from each other by a depth of about twice, so that an elastic body
9c has a thicker peripheral edge,
As shown in the figure, the opening of the metal case is prevented by cutting the elastic body due to variations in drawing and curling.
Further, since the elastic body 9c is fitted in the recessed portion of the peripheral portion, when the curling process is performed, there is no escape area for the elastic body and a strong airtight sealing is possible. In addition, the sealing body
Since the convex portion 9d is formed in the vicinity of the inner edge portion of the concave portion 9b of 9a, cracking due to the pressing force during curling does not occur.

Further, when the electrolytic capacitor having the above structure and the electrolytic liquid for driving the electrolytic capacitor of the conventional structure are examined for evaporation, as compared with the conventional product shown by the electrolytic capacitor b of the present invention shown by a as shown in FIG. The weight can be reduced by half, and the service life can be extended.

As described above, the electrolytic capacitor of the present invention is composed of the hard insulator and the elastic body, and since the main body of the sealing body of the hard insulator is the main body, the sealing body is deformed or warped. Since the convex portion is provided inside the sealing body to make it thicker, even if the curling process is strengthened, cracks do not occur and a strong airtight sealing is possible. Furthermore, the infiltration of halogen organic solvent etc. when cleaning the solder flux can be suppressed because the thickness of the elastic body at the peripheral portion is approximately double and the elastic body has a surface area of 40% or less, Prevents corrosion of capacitor elements and leads, stabilizes the characteristics, and reduces the evaporation of the driving electrolyte,
It has the advantage that it can have a long service life and has great industrial value.

[Brief description of drawings]

FIG. 1 is a partial sectional front view of an aluminum electrolytic capacitor according to an embodiment of the present invention, FIG. 2 is a sectional view of the same capacitor sealing body, and FIGS. 3A and 3B are front and back views of the sealing body. Fourth
The figure is a characteristic diagram showing the relationship between the elastic body surface area of the sealing body and the amount of solvent penetration, FIG. 5 is a characteristic comparison diagram of the product of the present invention and the conventional product, and FIG. 6 is a partial sectional front view of the conventional aluminum electrolytic capacitor. It is a figure. 6 ... Capacitor element, 7 ... Metal case, 9 ... Sealing body, 9a ... Sealing body, 9b, 9b '... Recessed portion, 9c ... Elastic body, 9d ... Convex portion.

Claims (1)

(57) [Claims] 1. A capacitor element obtained by winding an anode foil and a cathode foil together with a separator and impregnating a driving electrolytic solution is housed in a cylindrical metal case having a bottom, and the peripheral portion of the upper surface and the periphery of the lead-out portion. A hard insulating structure in which a concave portion is provided on the peripheral portion, the peripheral concave portion is made deeper than the periphery of the lead lead-out portion, and a convex portion is provided on the lower peripheral portion near the inner edge portion of the concave portion on the upper surface. An electrolytic capacitor in which an opening of the metal case is sealed by a sealing body made of a plate and an elastic body provided on the upper surface of the hard insulating plate so as to be embedded in the recess.