JP2001257135A - Capacitor with explosion-proof mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a capacitor with an explosion-proof mechanism of a structure that a thermal degradation of the capacitor is reduced to enable enhancing the life of the capacitor, the vibration resistance of the capacitor can be enhanced, a miniaturization of a device which is incorporated with the capacitor is enabled, and damage to the capacityor that is caused when the mechanism is actuated can be prevented. SOLUTION: A capacitor 17 with an explosion-proof mechanism is characterized by that with a capacitor element 1 housed in a case 3 with an explosion- proof mechanism 6, a cover 7 is mounted on this case 3 to seal the element 1 in the case 3, the wall thickness of the peripheral edges 5a of the bottom 4 of the case 3 is made thicker than that of the central part 5b of the bottom 4 to make the peripheral edges 5a project from only the sides of the outer surfaces of the bottom 4 and art the same time, the case 3 provided at the central part 5b has the thin wall-shaped explosion-proof mechanism 6 which is actuated during the time when the bottom 4 is deformed up to the height of the parts 5a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a capacitor with an explosion-proof mechanism.

[0002]

2. Description of the Related Art Capacitors 2 such as aluminum electrolytic capacitors
0 indicates that the capacitor element 21 is housed in a case 22 having an explosion-proof mechanism as shown in FIG.
2 has a structure in which a lid 23 is attached and sealed. The explosion-proof mechanism 24 is formed from a combination of groove-shaped thin portions provided on the bottom 25 of the case 22. When gas is ordered from the capacitor element 21 during use and the pressure in the case 22 increases during use, the entire bottom 25 of the case 22 expands together with the explosion-proof mechanism 24. When the pressure reaches a predetermined value, the explosion-proof mechanism 24 operates, and gas is released to the outside of the case 22. As a result, the capacitor 2
0 escapes the explosion.

[0003]

However, in the conventional capacitor 20, when the pressure inside the case 22 rises and the bottom 25 expands, most of the bottom surface of the capacitor element 21 separates from the bottom 25 of the case 22 and comes into contact. Disappears. For this reason,
The heat of the capacitor element 21 is hardly dissipated through the bottom 25 of the case 22, and the capacitor 20 has a disadvantage that the capacitor 20 is easily deteriorated by heat. In addition, there is a disadvantage that the capacitor element 21 is easily moved by external mechanical pressure such as vibration, and a contact failure or disconnection failure is easily generated at the position of the lead wire 26 pulled out from the capacitor element 21. In order for the explosion-proof mechanism 24 to operate, the bottom 25 of the case 22 is required.
There must be a space on the side where the bottom 25 can expand. For this reason, conventionally, a device for mounting the capacitor 20 has to have a structure in which a space of 5 mm or more is provided on the bottom 25 side of the capacitor 20, and there is a disadvantage that it is difficult to downsize the device. Furthermore, when the pressure in the case 22 rises sharply,
There is a drawback that the explosion-proof mechanism 24 operates suddenly, the capacitor element 21 easily jumps out of the case 22, and the built-in device is easily damaged.

[0004] The present invention improves the above disadvantages, reduces the heat degradation, improves the service life, improves the vibration resistance, enables the built-in device to be downsized, and prevents damage when the explosion-proof mechanism is activated. It is an object of the present invention to provide a capacitor with an explosion-proof mechanism.

[0005]

According to a first aspect of the present invention, there is provided an explosion-proof mechanism in which a capacitor element is housed in a case having an explosion-proof mechanism and a lid is attached to the case to seal the case. In the capacitor, the peripheral portion of the bottom portion is made thicker than the central portion so as to protrude only from the outer surface side, and a thin-walled explosion-proof mechanism that operates while deforming to the height of the peripheral portion is provided in the central portion. It forms a case.

According to a second aspect of the present invention, in the above-described capacitor with an explosion-proof mechanism, the height of the bottom of the case projecting from the central portion of the peripheral portion is set to 2.3 mm or more.

In other words, according to the present invention, the peripheral portion of the case bottom is made thicker than the central portion, so that when the pressure in the case increases, the peripheral portion expands and deforms even if the central portion expands. Is not easily deformed. For this reason, even if the bottom surface of the capacitor element does not come into contact with the central portion of the case bottom portion, the contact state with the peripheral portion can be maintained. Therefore, the heat of the capacitor element can be easily dissipated to the outside of the case through the peripheral portion at the bottom of the case, and the thermal deterioration of the capacitor can be reduced. Further, even if the pressure in the case increases, the bottom of the capacitor element is in contact with the peripheral portion of the bottom of the case, so that the vibration resistance of the capacitor can be easily improved.
The present invention provides an explosion-proof mechanism in which the peripheral portion of the case bottom is made thicker than the central portion and protrudes only from the outer surface side, and an explosion-proof mechanism is provided at the central portion, and the central portion is deformed to the height of the peripheral portion. The mechanism is working. In addition, the diameter of the central portion is smaller than the diameter of the entire case bottom by at least the width of the peripheral portion, so that the explosion-proof mechanism can be operated with a smaller deformation than when the entire bottom is deformed. Therefore, there is no need to provide a space of at least 5 mm on the bottom side of the case to operate the explosion-proof mechanism,
It is sufficient to provide a space of about 1 mm to allow the released gas to escape, so that the size of the device incorporating the condenser can be reduced.
By setting the protruding height of the peripheral portion of the case bottom from the central portion to 2.3 mm or more, a space in which the central portion can expand and deform can be sufficiently secured, and the explosion-proof mechanism can be operated more reliably. Furthermore, even when the pressure inside the case rises sharply and the explosion-proof mechanism is activated, the capacitor element is supported inside the case with its bottom surface in contact with the peripheral edge of the case bottom. Never jump out. Therefore, it is possible to prevent the device incorporating the capacitor from being damaged.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a capacitor element. The capacitor element 1 has a structure in which, for example, an anode foil and a cathode foil are laminated via electrolytic paper and wound, and an anode lead wire 2a and a cathode lead wire 2b are drawn out. The anode foil is formed by forming an oxide film on a valve metal foil such as an etched high-purity aluminum foil and connecting the anode lead wire 2a. As the cathode foil, one obtained by connecting a cathode lead wire 2b to a valve action metal foil such as an etched aluminum foil is used. Electrolytic paper uses manila paper or kraft paper.
The capacitor element 1 may have a structure in which the cathode foil protrudes from the bottom surface opposite to the direction in which the cathode lead wire 2b is drawn out, and the protruded cathode foil is brought into contact with the inner bottom surface of the case 3, thereby providing a heat radiation effect. And the allowable ripple current can be increased. In addition, as the capacitor element 1, a metallized paper or a metallized film obtained by vacuum-depositing zinc or the like on a capacitor paper or a plastic film is wound, a metallikon is provided on both end surfaces, and a lead wire is connected to the metallikon. May be used.

The case 3 is made of a metal material such as aluminum.
It is formed in a cylindrical shape in appearance. The bottom portion 4 of the case 3 has a thicker peripheral portion 5a and a central portion 5b.
The peripheral portion 5a protrudes from the central portion 5b only to the outer surface side, does not protrude to the inner surface side, and the peripheral portion 5a and the central portion 5b are flush with each other on the inner surface side. An explosion-proof mechanism 6 is provided in the center portion 5b of the bottom 4 of the case 3 by arranging grooves in a cross shape, a large shape, an S shape, or the like. By setting the height h at which the peripheral portion 5a protrudes from the central portion 5b to 2.3 mm or more, a sufficient space for the operation of the explosion-proof mechanism 6 can be ensured, and the explosion-proof mechanism 6 can be operated more reliably. Further, the peripheral portion 5a and the central portion 5b are connected by a connecting portion 5c whose thickness gradually changes, but may be directly connected.

Reference numeral 7 denotes a lid, which is made of an insulating resin such as polyphenylene sulfide or phenol, and has a thickness of 3 mm to 1 mm.
It has a thickness of about 0 mm, is placed on a projection 9 provided on the inner peripheral surface of the case 3 in the vicinity of the square 8, and is mounted on the case 3 by curling the square 8. Further, the peripheral portion 10a of the lid 7
Has a step with respect to the central portion 10b which is thin and has a projection 11 having a triangular cross section, and an elastic band 12 made of an elastic material such as rubber is arranged. The bent end of the bent square 8 of the case 3 is inserted into the elastic band 12 to improve the sealing performance. In addition, a rubber-laminated laminated board in which rubber such as EPT is bonded to bakelite or the like may be used as the lid. Also, the anode terminal 1 is provided on the lid 7.
3a and the cathode terminal 13b are provided penetrating therethrough. The anode lead 2a is connected to the anode terminal 13a by riveting or ultrasonic welding, and the cathode lead 2b is connected to the cathode terminal 13b by a similar method.
Further, a reinforcing terminal 14 is provided on the lid 7. The reinforcing terminal 14 has one end 15a protruding out of the case 3 to the same height as the anode terminal 13a and the cathode terminal 13b, but the other end 15b of the capacitor element 1 is embedded in the lid 7 and is inserted into the case 3. Does not protrude. Therefore, Case 3
There is no need to insulate the reinforcing terminals 14 in the inside, and the manufacturing becomes easy. The number of the reinforcing terminals 14 may be not limited to one but may be two or more. In particular, when the diameter of the capacitor is large, as the number increases, the vibration resistance improves. The case 3 is covered with an insulating tube 16.

Next, a method of manufacturing the capacitor 17 with the explosion-proof mechanism will be described. First, an anode lead wire 2a is connected to an anode foil having an oxide film formed by subjecting a valve metal such as aluminum to an etching treatment and anodizing treatment by a cold welding method, a caulking method, or the like. Further, a cathode lead wire 2b is connected to the cathode foil by a cold welding method or the like. Then, the anode foil and the cathode foil are overlapped and wound via an electrolytic paper to form the capacitor element 1. Next, the capacitor element 1 is impregnated with an electrolytic solution by a vacuum impregnation method, a vacuum pressure impregnation method, or the like. Also, the anode terminal 13a and the cathode terminal 13
Both ends of b and one end of the reinforcing terminal 14 are pulled out, molded by resin, and the elastic band 12 is fitted thereon to form the lid 7. Further, the case 3 is manufactured by molding an aluminum plate or the like into a mold. Then, the anode lead 2a and the cathode lead 2b drawn from the capacitor element 1 are connected to the anode terminal 13a and the cathode terminal 13b, respectively, so that the capacitor element 1 and the lid 7 are integrated. After this, the capacitor element 1
Is stored in the case 3, the square 8 of the case 3 is curled, the lid 7 is attached to the case 3, and the case 3 is sealed. After sealing, aging is performed by applying a voltage higher than the rated voltage while gradually increasing the pressure in a high-temperature atmosphere.

[0012]

EXAMPLE Next, an operation test of the explosion-proof mechanism was performed for the example. The capacitors with explosion-proof mechanism used in the test and the operation test are under the following conditions. Explosion-proof capacitor: Type-Aluminum electrolytic capacitor Rated-400 V, 1000 µF Overall shape-Cylindrical case with a diameter of 51.0 mm and length of 51.0 mm Bottom-Peripheral part Wall thickness 2.8 mm, diameter 33.0 to 33.0
50.0mm center part wall thickness 0.5mm, diameter 25.0mm connecting part wall thickness 0.5-2.8mm, diameter 25.0-3
3.0mm Explosion-proof mechanism-A 16.0mm long, 0.08mm deep groove is formed in a cross shape. Case side-wall thickness 0.55mm

[0013] Operation test: 600V. DC, 7A is applied. The number of samples is 20
And

As a result of the test, the explosion-proof mechanism was activated in about 9 seconds after the application of 600 V, and the explosion was avoided. And the explosion-proof mechanism was activated before the central part reached the height of the outer surface of the peripheral part.

[0015]

As described above, according to the present invention, in a capacitor with an explosion-proof mechanism in which a capacitor element is housed in a case with an explosion-proof mechanism and a lid is attached to the case to seal the case, the peripheral portion at the bottom of the case is centered. It has a thicker wall than the outer surface, and has a thin explosion-proof mechanism that operates while deforming to the height of the peripheral edge. It is possible to obtain a capacitor with an explosion-proof mechanism that can reduce deterioration, improve life, improve vibration resistance, reduce the size of a built-in device, and prevent damage to the device due to the protrusion of a capacitor element when the explosion-proof mechanism operates.

In particular, by making the height of the bottom of the case projecting from the central portion of the peripheral portion to 2.3 mm or more,
A capacitor with an explosion-proof mechanism can be obtained that can operate the explosion-proof mechanism more reliably and improve reliability and safety.

[Brief description of the drawings]

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

FIG. 2 is a sectional view of a conventional capacitor with an explosion-proof mechanism.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Capacitor element, 3 ... Case, 4 ... Bottom part, 5a
... peripheral part, 5b ... central part, 5c ... connecting part, 6 ...
Explosion-proof mechanism, 7: Lid, 17: Capacitor with explosion-proof mechanism. Reference number P2533

Claims (2)

[Claims] 1. A capacitor with an explosion-proof mechanism in which a capacitor element is housed in a case with an explosion-proof mechanism, and a lid is attached to the case to seal the explosion-proof mechanism. A case provided with a thin-walled explosion-proof mechanism provided in the center portion, the thin-walled explosion-proof mechanism operating while being deformed to the height of the peripheral portion. 2. The capacitor with an explosion-proof mechanism according to claim 1, wherein the height of the case bottom from the center of the peripheral portion is 2.3 mm or more.