JP3458616B2 - Explosion-proof capacitor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitor case. 2. Description of the Related Art A capacitor such as an aluminum electrolytic capacitor has a structure in which a capacitor element is housed in a case made of metal or the like, a case is sealed with a lid, and terminals are pulled out from the lid. When an overvoltage or a reverse polarity voltage is applied to this capacitor, heat is generated and the temperature rises, and the pressure inside the case increases. When this pressure exceeds a predetermined value, an accident of explosion of the capacitor occurs. Conventionally, in order to prevent this accident beforehand,
For example, as shown in FIG. 5A, a groove 23 is provided in the center of the bottom surface 22 outside the case 21. That is, when the gas pressure in the case 21 increases, first, the bottom surface 22 of the case 21 provided with the groove 23 expands. When the gas pressure further rises, the groove 23 bursts as shown in FIG. When the groove 23 ruptures, the gas in the case 21 passes through a hole in the center of the capacitor element 25 and a gap 26 between the bottom surface 24 inside the case 21 and the capacitor element 25, passes through the ruptured groove 23, and passes through the case 23. Release outside 21. This prevents an accidental explosion of the capacitor. [0004] However, if the momentum is strong when the gas is discharged out of the case 21, FIG.
2, the bottom end 27 of the capacitor element 25 is in close contact with the bottom surface 24 of the case 21. As a result, gas cannot be released from the temporarily ruptured groove 23, and the case 2
1 is filled with gas. Then, there is a disadvantage that the center of the capacitor element 25 is pushed out of the case 21 by about 1 cm outside due to the pressure of the filled gas. An object of the present invention is to provide a capacitor with an explosion-proof mechanism which can solve the above-mentioned drawbacks and can prevent an accident in which a capacitor element jumps out. [0006] In order to solve the above-mentioned problems, the present invention provides an explosion-proof mechanism in which a capacitor element is housed in a case having a groove on the bottom surface, and a lid is attached to the case to seal the case. An object of the present invention is to provide a capacitor with an explosion-proof mechanism, characterized in that a projection is provided on a part of the end of the bottom surface inside the case. According to the present invention, when the groove in the bottom surface of the case ruptures and gas in the case is released, when the capacitor element moves toward the bottom surface of the case, the capacitor element comes into contact with a projection provided at an end of the bottom surface. . However, the protrusion is only provided on a part of the end of the case bottom surface. The bottom end of the capacitor element is separated from the bottom of the case without being in close contact with the bottom of the case.
Therefore, a path for releasing gas can be secured between the capacitor element and the case. For this reason, the gas in the case is discharged out of the case without stopping after the rupture of the groove. This can prevent the capacitor element from being pushed out of the case and jumping out. Embodiments of the present invention will be described below with reference to the drawings. In FIGS. 1 (a) and (b),
Reference numeral 1 denotes a cylindrical case made of aluminum metal or the like. At the center of the bottom surface 2 on the outside of the case 1, three grooves 3 extending radially from the center, and a long linear groove 4 intersecting one of the three grooves 3 And an explosion-proof mechanism consisting of: The groove may be provided at the center of the bottom surface 5 inside the case 1. In addition, the bottom surface 5 inside the case 1
Is provided with a horseshoe-shaped projection 6 at a part of its end.
As shown in FIG. 2, the projections 7 may be formed in an arc shape, and two or three or more projections 7 may be provided. Further, as shown in FIG. 3, a large number of minute projections 8 may be provided. The longer the interval between the projections and the higher the projections, the easier the gas can be released. 9 is a capacitor element housed in the case 11.
The capacitor element 9 is formed, for example, by laminating and winding an anode foil and a cathode foil via electrolytic paper, connecting an anode lead wire 10 to the anode foil, and connecting a cathode lead wire 11 to the cathode foil. It is structured to be pulled out from both ends. The bottom end 12 of the capacitor element 9 is in contact with the protrusion 6. 13
Is a lid that is attached to the open end of the case 1 and seals the case 1, and is formed by molding an insulating resin such as epoxy,
Rubber is attached to a bake plate. The lid 13 is provided with an anode terminal 14 and a cathode terminal 15 therethrough. The anode lead wire 10 is connected to the anode terminal 14, and the cathode lead wire 11 is connected to the cathode terminal 15. Next, a method of manufacturing the capacitor 16 with a security mechanism will be described. First, an anode lead wire 10 is connected to an anode foil having an oxide film formed by etching a valve metal such as aluminum and forming an oxide film by anodization, and one end of the anode lead wire 10 is connected to the anode foil. Pull out in the width direction. Further, a cathode lead wire 11 is connected to a cathode foil etched with a valve metal such as aluminum by a cold weld method, and one end thereof is drawn out in the width direction of the cathode foil. Then, the anode foil and the cathode foil are overlapped with each other via an electrolytic paper and wound to form a capacitor element 9. Alternatively, a metallized film obtained by vapor-depositing aluminum, zinc, or the like on a polymer film or the like may be laminated and wound, a metallikon may be formed on an end face, and a lead wire may be connected to the metallikon to form a capacitor element. Next, the capacitor element 9 is impregnated with an electrolytic solution by a vacuum impregnation method, a vacuum pressure impregnation method, or the like. After the impregnation, the anode lead 10 and the cathode lead 11 are connected to the anode terminal 14 and the cathode terminal 15, respectively. After this connection, the capacitor element 9 is stored in the case 1. At this time, the end 12 of the bottom surface of the capacitor element 9 contacts the projection 6 of the case 1. After storing the capacitor element 9 in the case 1, the cover 13 is attached by caulking to the open end of the case 1.
Seal. After the case 1 is sealed, in the case of an electrolytic capacitor, in a high-temperature atmosphere, aging treatment is performed by finally applying a voltage higher than the rated voltage while gradually increasing the voltage. When an overvoltage or a reverse polarity voltage is applied to the capacitor 16 with a security mechanism, the capacitor element 9 generates heat and the gas pressure in the case 1 increases. When the gas pressure in the case 1 reaches a predetermined value, the grooves 3 and 4 on the bottom surface 2 of the case 1 burst as shown in FIG. In this case, since the capacitor element 9 is in contact with the protrusion 6 provided on the case bottom surface 5 and a gas discharge path is secured, the gas is discharged smoothly out of the case 1. Therefore, it is possible to prevent a failure such as the capacitor element 9 jumping out of the case 1. [0011] Examples of the present invention, together with the conventional example, were subjected to a test for applying an overvoltage, and the change in appearance was measured. Both the embodiment and the conventional example have a rating of 400 V-330.
Use a μF aluminum electrolytic capacitor. The former has a structure as shown in FIG. 1, and the latter uses a case as shown in FIG. The test conditions are an applied voltage of 700 V DC, a current of 10 A, and an ambient temperature of normal temperature.
The number of samples is 50 each. As a result of the test, in all the examples, no protrusion of the capacitor element was found. On the other hand, in the conventional example, there were three defects in which the central portion of the capacitor element protruded, and one defect in which the capacitor element was completely protruded. As described above, according to the present invention, a groove is provided on the bottom surface of the case to provide an explosion-proof mechanism, and a projection is provided on a part of the end of the bottom surface inside the case. A highly reliable capacitor with a security mechanism that can prevent the capacitor element from jumping out can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a sectional view and a bottom view of an embodiment of the present invention. FIG. 2 shows a bottom view of a case used in another embodiment of the present invention. FIG. 3 shows a bottom view of a case used in another embodiment of the present invention. FIG. 4 is a cross-sectional view showing a state in which the groove according to the embodiment of the present invention has burst. FIG. 5 shows sectional views of a conventional capacitor with a security mechanism in a normal state and a state in which a groove is ruptured. [Description of reference numerals] 1 ... case, 2 ... outer bottom surface, 3, 4 ... groove, 5 ...
Inner bottom surface, 6, 7, 8 ... projection, 9 ... capacitor element, 13 ... lid, 16 ... capacitor with security mechanism.

Claims (1)

(57) [Claim 1] In a capacitor with an explosion-proof mechanism in which a capacitor element is housed in a case provided with a groove on the bottom surface and a lid is attached to the case to seal the case, an end of the bottom surface inside the case is provided. A capacitor with an explosion-proof mechanism, characterized in that a protrusion is provided on a part of the capacitor.