JP2003142349A - Electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems of a conventional explosion-proof valve being difficult to be adapted to a flat-shape electrolytic capacitor, because of the limitation brought about by its flat shape, and of accommodating a capacitor element, which has been swollen being impregnated with an electrolyte into a case invites lowering of the accommodation capacity, because the flat-shape capacitor permits the capacitor element to have a particularly large contact area with the case. SOLUTION: The electrolytic capacitor is provided with a sealing body at an opening of the case, in which a through-hole and a sealant for sealing the through-hole are provided. When the inside pressure of the case has reached a given pressure, the sealant moves in the direction for releasing the pressure to exert an explosion-proof function. Such a structure provides an electrolytic capacitor, that matches a flat shape. Since the electrolyte is injected from the through-hole, after the capacitor element has been accommodated in the case, the capacitor element can be readily accommodated, to prevent lowering of the accommodation capacity.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electrolytic capacitor,
In particular, the present invention relates to a sealed body having an explosion-proof function for a flat electrolytic capacitor having excellent storage capacity.

[0002]

2. Description of the Related Art Generally, in an electrolytic capacitor, a capacitor element impregnated with an electrolytic solution is housed in a case, lead terminals are drawn out to the opening of the case and sealed with a sealing body.
The explosion-proof mechanism of the electrolytic capacitor is provided with a stamp on the case to partially reduce the thickness of the case, and when the case reaches a predetermined pressure and the case deforms, the stamped part breaks to release the internal pressure. Method (first method). A through hole is provided in the hard plastic mold sealing body, and a soft plastic plug such as silicon is plugged into this hole.
A method in which a thin portion is provided and the internal pressure is released by breaking the thin portion when a predetermined pressure is reached (second method). A method in which a thin-walled portion is provided as a whole with a rubber sealing body and a thin-walled portion is broken when a predetermined pressure is reached to release the internal pressure (third method). A method in which a rubber sheet is bonded and laminated on a paper phenol plate having a through hole to form a sealing body, and when a predetermined pressure is reached, the rubber sheet in the through hole portion is broken to release the internal pressure (fourth method) ) And other weak areas,
When the internal pressure of the condenser reaches a predetermined pressure, the weak portion is broken to release the internal pressure.

[0003]

However, it is difficult to adopt the above-mentioned conventional example in the flat type electrolytic capacitor due to its flat shape restriction. That is, in the engraving method of the first method, it is necessary to deform the case, that is, to secure an operating space, and it is not possible to make full use of the characteristics of the flat electrolytic capacitor excellent in storage capacity. Further, since the sealing body of the flat type electrolytic capacitor is elongated, it is difficult to mount the snare on the sealing body by the method of the second method, which is the soft plastic plug, and the sealing method of the rubber material of the third method. In the body, it is difficult to process thin parts. Further, for the same reason, in the laminated sealing body of the fourth method, the laminated rubber sheet also serves as a sealing and packing for terminals, so that it is difficult to design the sealing body.

Further, in the flat type, since the contact area between the capacitor element and the case is particularly large, it is impregnated with the electrolytic solution.
When the swollen capacitor element is housed in the case, the storage capacity is lowered, and there is a case where a sealing failure occurs when measures are taken to fix the capacitor element or the sealing process is performed with the electrolytic solution adhering to the inner surface of the case.

An object of the present invention is to provide an electrolytic capacitor having an explosion-proof mechanism adapted to a flat shape.

[0006]

In order to solve the above problems, the present invention provides an electrolytic capacitor in which a through hole and a sealing body for sealing the through hole are provided in a sealing body arranged in a case opening. There is provided the electrolytic capacitor, wherein the sealing body moves in a direction of opening it when the internal pressure of the case reaches a predetermined pressure.

Also provided is an electrolytic capacitor in which the sealing body is a sphere, and the through hole is provided with a tapered portion, a squeezed portion, a protrusion portion, or a slit portion. It is a thing.

Further, the present invention provides an electrolytic capacitor in which the cross-sectional shape of the entrance of the through hole and the cross-sectional shape of the sealing body are dissimilar to each other.

With such a structure, it is possible to provide an electrolytic capacitor having a flat shape.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a sectional view of the electrolytic capacitor of the present invention. A capacitor element 1 has a structure in which an anode foil and a cathode foil are laminated with a separator such as electrolytic paper interposed therebetween. Reference numeral 2 is a lead terminal drawn out from the capacitor element. Reference numeral 3 denotes a case made of metal or plastic, which has a flat shape. Reference numeral 4 denotes a sealing body which is attached to the case 5 and which is hermetically sealed. The sealing body 4 is an elastic body such as rubber or plastic elastomer, or hard plastic. Reference numeral 5 is a through hole provided in the sealing body 4. The shape of the through hole 5 is generally cylindrical, but it may be tapered or its cross section may be polygonal or elliptical. Reference numeral 6 denotes a sealing body that is provided in the through hole 5 and seals the through hole 5, and is an elastic body such as hard plastic, metal or ceramic, rubber or plastic elastomer, or a composite thereof. Metals and the like for elastic body coating are also included. As long as the cross section of the sealing body is similar to the cross section of the through hole, the shape should be close to a spherical shape, an elliptical shape, or a cylindrical shape, and it is not necessary to align the directions when inserting into the through hole. Spheres are particularly preferred.

Further, as shown in FIG. 3, a taper portion 8 is provided at a portion of the through hole 5 where the sealing body 6 is inserted (an entrance portion of the through hole 5).
Is provided so that the insertion portion is widened, the sealing body 6 can be easily inserted.

Further, as shown in FIG. 4, when a stopper portion 9 for the sealing body 6 is provided at the bottom portion of the through hole 5, the sealing body 6 is provided.
It is preferable because it can be prevented from falling off from the sealing body 4 when it is inserted into the through hole 5. As the shape of the stopper portion 9, a cylindrical two-step hole shape in FIG. 4A, a protrusion shape in FIG. 4B, a tapered shape in FIG. 4C, and a shape in FIG. 4D. Many small hole shapes can be introduced.

Since the laminated type capacitor element expands greatly when it is impregnated with the electrolytic solution as compared with the wound type, it is easier to store the capacitor element in the case without impregnating the electrolytic solution. Further, since the capacitor element is easily fixed to the case after impregnation, if the electrolytic solution is injected from the through hole of the sealing body after the capacitor element is housed in the case, the electrolytic solution may remain in the through hole, It is effective to provide a coating of oil-and-fat wax, fluorine, a silicon-based resin, or the like on the inner surface of the through hole for water repellency treatment and airtightness enhancement.

In order to obtain airtightness between the sealing body and the sealing body, when the sealing body is a hard body, the sealing body is an elastic body, and when the sealing body is an elastic body, the sealing body is an elastic body or a hard body. preferable. Further, when the sealing body is a hard body, as shown in FIG. 2, in particular, in order to obtain airtightness between the sealing body 41 and the case 3 or the sealing body 41 and the lead terminals, a resin 7 is formed on the surface of the sealing body 41.
Is preferably filled.

In the case of a general columnar through hole,
When the internal pressure of the capacitor increases and the predetermined pressure is exceeded, the sealing body rises to the outside through the through hole and finally pops out, which may adversely affect other electronic components. Therefore, the cross-sectional shape of the entrance portion of the through hole 5 is not similar to the cross-sectional shape of the sealing body 5 for that reason, so that the cross-sectional shape of the sealing body 5 relative to the cross-sectional shape of the sealing body 5 is relatively small when the sealing body covers this portion. Since there is a gap between the through hole 5 and the sealing body due to the difference, the internal pressure is released and the sealing body can be prevented from popping out unless the internal pressure is explosively increased. The entry portion of the through hole refers to the entry portion where the sealing body is inserted into the through hole. Taking a spherical body as an example of the sealing body, a method of providing the protrusion 10 as shown in FIG. 5A-1, a method of providing the slit 11 as shown in FIG. 5B-1, and FIG. Elliptic cylindrical portion 1 whose minor axis is shorter than the diameter of the sphere and whose major axis is longer than the diameter of the sphere, as in (c-1)
2 may be provided. In addition, (a-1) of FIG.
(B-1) and (c-1) are top views, respectively.

[0016]

As described above, in the electrolytic capacitor provided with the through hole and the sealing body for sealing the through hole in the sealing body arranged in the case opening, as described above, when the internal pressure of the case reaches a predetermined pressure. Since the sealing body moves in the direction to open it, it has an explosion-proof function suitable for a flat electrolytic capacitor. Further, when the through hole has a tapered portion, the sealing body can be easily inserted into the through hole, and when the stopper portion is provided, the sealing body can stably seal in the through hole. Further, by making the cross-sectional shape of the entrance portion of the through hole non-similar to the cross-sectional shape of the sealing body, the sealing body can release gas without jumping out of the through hole. In addition, since the sealing of the explosion-proof function and the injection hole of the electrolytic solution are simultaneously performed, the number of working steps can be reduced, and the through-hole can also be used, so that the size can be reduced. Further, since the electrolytic solution can be injected after the capacitor element is housed in the case, it is possible to provide an electrolytic capacitor adapted to a flat shape which can have a large storage capacity.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a sectional view of another embodiment of the present invention.

FIG. 3 is a cross-sectional view of the tapered portion at the entrance of the through hole of the present invention.

FIG. 4 is a sectional view of a stopper portion of a through hole according to the present invention.

5A and 5B are a sectional view and a top view of an entrance portion of a through hole according to the present invention.

[Explanation of symbols]

1 ... Capacitor element 2 ... Lead terminal 3 ... Case
4, 41 ... Sealing body 5 ... Through hole 6, 61 ... Sealing body 7
... Resin 8 ... Tapered portion 9, 91, 92, 93 ... Stopper portion 10 ... Projection portion 11 ... Slit portion 12 ... Elliptical columnar portion.

Claims (4)

[Claims] 1. An electrolytic capacitor in which a through hole and a sealing body for sealing the through hole are provided in a sealing body arranged in the opening of the case, wherein the internal pressure of the case reaches a predetermined pressure. Then, the electrolytic capacitor is characterized by moving in the direction to open it. 2. The electrolytic capacitor according to claim 1, wherein the sealing body is a sphere. 3. The electrolytic capacitor according to claim 1, wherein the through hole is provided with a tapered portion, a squeezed portion, a protrusion portion, or a slit portion. 4. The electrolytic capacitor according to claim 1, wherein the cross-sectional shape of the entrance portion of the through hole and the cross-sectional shape of the sealing body are dissimilar to each other.