JPH0142337Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an explosion-proof device for a flat electrolytic capacitor.

In general, electrolytic capacitors, especially dry electrolytic capacitors, have a structure in which a valve metal such as aluminum is used for the anode electrode part, an oxide layer of the metal is formed as a dielectric on the surface of the anode part, and the oxide layer faces the cathode part via an electrolyte. has polarity, and since there is a liquid electrolyte inside the electrolytic capacitor, an increase in current due to reverse connections or short circuits will cause rapid chemical reactions and heat generation inside the capacitor, causing a sudden rise in internal pressure. There is a risk of rupture. For this reason, electrolytic capacitors are usually equipped with an explosion-proof device to prevent them from bursting.

As shown in FIG. 1, this explosion-proof device is a normal electrolytic capacitor having a cylindrical body, that is, a capacitor element 2 wound in a cylindrical shape is housed in a bottomed cylindrical metal outer case 1. The opening of the exterior case 1 is closed with an elastic sealing body 3 made of disc-shaped rubber or the like, and a lead wire 4 drawn out from the capacitor element 2 passes through a through hole 5 provided in the elastic sealing body 3 to the outside. In the case where the explosion-proof device has a structure that protrudes from the outside, the explosion-proof device has a thin wall portion 6 formed on the bottom of the outer case 1, or a thin wall portion 7 is formed on a part of the elastic sealing body 3, etc. Some have more vulnerable parts. In the case of an electrolytic capacitor having this structure, when the internal pressure rises abnormally, the fragile portion ruptures, and the high pressure gas inside is dissipated to the outside of the capacitor, thereby preventing the electrolytic capacitor body from rupturing.

As described above, various explosion-proof devices have been considered for electrolytic capacitors with a general shape, but electrolytic capacitors with a flat external shape, that is, a flat capacitor element is housed inside,
A capacitor has a structure in which the upper and lower surfaces are covered by an exterior flat plate made of a metal plate, etc., a packing material made of an elastic material such as rubber is placed around the periphery, and the periphery of the exterior flat plate is held and sealed with elastic clamping tools. Since the thinness of the plate is used to attach it to the equipment, there is no margin in the thickness direction, and sometimes the flat plate itself acts as a chassis, or other parts are mounted directly on the flat plate. Therefore, it is difficult to create an explosion-proof device by providing a thin wall part on the flat exterior plate. Furthermore, since the packing material on the periphery has almost no thickness, there is not enough room to provide a thin wall portion, and if the thin wall portion is formed by force, there is a risk of problems such as poor airtightness.

The purpose of this invention is to provide a simple and reliable explosion-proof device suitable for the above-mentioned flat plate electrolytic capacitor.

This invention will be explained in detail below based on examples.
FIG. 2 is an exploded perspective view showing the flat electrolytic capacitor of this invention, showing the capacitor element 20 formed into a flat shape by winding or stacking the anode side electrode and the cathode side electrode with electrolytic paper interposed therebetween, and its upper surface. Plate-shaped exterior flat plates 21 and 22 made of metal plates or the like are arranged so as to be in contact with the lower surface of the capacitor element 20, and a packing member 23 is arranged at the periphery of the capacitor element 20 so as to surround the capacitor element 20.
The capacitor element 20 has its upper and lower surfaces covered with exterior flat plates 21 and 22, and its periphery covered with a packing member 23 so as to be hermetically sealed. From the capacitor element 20, external leads 24 are electrically connected to both the anode side and the cathode side electrodes, respectively.
25 is drawn out from the end face of the element 20. Further, the packing member 23 is provided with through holes 26 and 27 at positions that coincide with the lead-out portions of the external leads 24 and 25, and the external leads 24 and 25 project outward from the through holes 26 and 27. It's getting old. Further, on the other side of the packing member 23, a notch 28 is provided halfway from the outside toward the inside.

The capacitor element 20 is sealed by fitting an elastic clamping tool 12 having a substantially U-shaped cross section into each peripheral edge of the plate-shaped exterior flat plates 21 and 22 that sandwich the capacitor element 20 from the upper and lower surfaces. It has a sandwiched structure.

FIG. 3 is a partially enlarged cross-sectional view showing this sandwiched state, in which a packing member 23 is arranged at the periphery so as to surround the capacitor element 20, and further, exterior flat plates 21 and 22 are located on the upper and lower surfaces thereof. . Then, the clamping tool 12 having a substantially U-shaped cross section is fitted from the outside, and the opening tip of the clamping tool 12 engages with the groove 29 provided on the outer surface periphery of the exterior flat plates 21 and 22, and the clamping tool 12 falls out. It prevents
Further, the back surface of the groove 29 is directed inward, and the protrusion 30
This protrusion 30 bites into the packing member 23 to strengthen the seal.

Note that this clamping tool 12 is not attached to the portions that contact the positions where the through holes 26, 27 and the notches 28 for pulling out external leads are provided, and is open to the outside. The explosion-proof device is configured so that the high-pressure gas inside does not dissipate to the outside when the explosion-proof device is in operation.

FIG. 4 is a perspective view showing the completed assembled state of the capacitor shown in FIG. 2, in which the capacitor element is covered with a packing member 23 on its peripheral edge and with exterior flat plates 21 and 22 on its upper and lower surfaces. It is shown that the peripheral edges of the exterior flat plates 21 and 22 between which the packing member 23 is located are pressed and sealed by the elastic force of the clamping tool 12. As described above, the clamping tool 12 is not attached to the vicinity of the lead-out portions of the external leads 24 and 25 and to the portion where the notch 28 is provided.

In the electrolytic capacitor of this invention constructed in this way, when the internal pressure suddenly increases due to an increase in current due to reverse connection, short circuit, etc., the internal pressure causes the clamping member 12 to be disposed in the portion where it is not attached and in the packing member 23. The high-pressure gas inside the electrolytic capacitor is gradually dissipated to the outside through the thin part of the notch 28, thereby reducing the pressure inside the electrolytic capacitor to provide an explosion-proof operation.

Further, when the internal pressure of the electrolytic capacitor is suddenly increased, cracks are generated in the notches 28, and the high-pressure gas inside can be released to the outside through the cracks.

In addition, this notch 28 was provided at one location in the embodiment, but it is not shown in FIG. 5A.
As shown in Figure B, the cut may extend to the inside, or as shown in Figure B, two or more cuts may be provided in close proximity to each other. Further, such an explosion-proof device may be installed at two or more locations, for example, on each side of the capacitor.

Further, the exposed area of the packing member corresponding to the portion where the clamping tool is not attached may be freely set according to the explosion-proof operation pressure.

Furthermore, although not shown, the cut may be a cut directed outward from the inside of the packing member,
The cuts may be directed in a direction different from the thickness direction of the packing member as in the embodiment.

According to this invention, an explosion-proof device can be installed on the flat electrolytic capacitor without losing the advantage of the flat electrolytic capacitor, which is that it can be installed in a narrow space. Moreover, the explosion-proof device according to this invention does not require any special parts or materials, so it is easy to process and assemble.

In addition, since the clamping tool that surrounds the packing member is not installed near the explosion-proof device, the exposed area of the packing member where the clamping tool is not attached is calculated as the length of the packing member. By adjusting the fluctuation, it becomes possible to freely adjust the internal pressure value at which the explosion-proof device for the flat electrolytic capacitor according to this invention operates.

Furthermore, since the notch is closed during normal use, reliable sealing can be achieved, and the explosion-proof operating part will not deteriorate, allowing stable characteristics to be maintained over a long period of time.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing the internal structure of a normal cylindrical electrolytic capacitor, Figure 2 is an exploded perspective view showing the internal structure of the flat electrolytic capacitor of this invention, and Figure 3 is a cross-sectional view showing the internal structure of a conventional cylindrical electrolytic capacitor. Figure 4 is a partially enlarged sectional view showing the sandwiched and sealed part of the electrolytic capacitor.
A perspective view showing the completed state of the capacitor shown in Figure 5.
The figure is a perspective view showing another embodiment of the explosion-proof device of this invention. 12... Holding tool, 20... Capacitor element, 2
1, 22... Exterior flat plate, 23... Packing member, 24, 25... External lead, 26, 27...
Through hole, 28...notch.

Claims (1)

[Scope of utility model registration request] The device includes a flat capacitor element, an exterior flat plate that covers the upper and lower surfaces of the capacitor element, a packing member made of an elastic material disposed at the periphery between the exterior flat plates so as to surround the capacitor element, and the packing member. A flat plate type electrolytic device, characterized in that the packing member is provided with one or more explosion-proof devices comprising means for clamping and sealing the peripheral edge of the exterior member, and each consisting of a cut in a direction perpendicular to the exterior flat plate. capacitor.