JPS6236629B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an electrolytic capacitor with an improved sealing plate.

Generally, electrolytic capacitors are as shown in Figure 1.
After each lead plate 1 is connected to the two electrode foils by caulking or the like, they are wound with electrolytic paper interposed therebetween to form a capacitor element 2, and the capacitor element 2 is impregnated with an electrolytic solution. Next, an external terminal 7 is attached in advance to a sealing plate 6 made of a laminated rubber sheet 3, a Bakelite plate 4, and a thin polypropylene sheet 5, and the lead plate 1 led out from the capacitor element 2 is connected to the external terminal 7 with rivets or the like. , is inserted into a case 9 in which the element fixing material 8 is injected, and the open end of the case 9 is sealed by winding. Reference numeral 10 denotes an explosion-proof hole provided in the sealing plate 6.

However, even if the sealing plate 6 attached to the open end of the case 9 made of aluminum or the like is sealed by seaming, the rubber sheet 3 constituting the sealing plate 6 cannot be used in long-term reliability tests, especially in tests at high temperatures. Due to aging, airtightness becomes incomplete at the circumferential end of the sealing plate 6 in contact with the case 9 and at the part where the external terminal 7 is attached with rivets, which is a factor that reduces reliability. In addition, in order to prevent impurities from adhering to the rivet connection part of the drawer lead plate 1 due to the electrolyte and causing corrosion, a polypropylene sheet 5 is pasted to the rubber sheet 3 and the Bakelite plate 4.
It is expensive because it is processed using three types of materials: and polypropylene sheet 5.

In addition, as seen in Japanese Utility Model Publication No. 35-25751, a rubber thin piece is coated on the entire circumference of the main panel on the opening side provided at the bottom of the capacitor outer casing to allow for tight sealing. A type with holes has been devised, but as mentioned above, in high-temperature tests, the electrolyte leaks from the small holes and the rubber flakes deteriorate, resulting in poor airtightness.

The present invention aims to eliminate the above-mentioned drawbacks and provide a method of manufacturing an electrolytic capacitor using a highly reliable and inexpensive sealing plate. That is,
External terminals are attached with rivets to a sealing plate in which the front and back or the entire surface of a hard insulating plate made of Bakelite, polypropylene, etc. are coated with organic synthetic rubber made of ethylene propylene terpolymer, isoprene, etc., and a drawer lead plate is derived from the rivets and capacitor elements. This method of manufacturing an electrolytic capacitor is characterized in that the sealing plate is inserted into the opening of the case, and the case is sealed by winding the case.

The present invention will be described below with reference to the embodiments shown in FIGS. 2 and 3.

Figure 2 shows the sealing plate of an electrolytic capacitor.
11 is a hard insulating board made of Bakelite or polypropylene, and 11 is an organic synthetic rubber such as ethylene propylene polymer or isoprene that is coated on the front, back, and side surfaces of the hard insulating board 10. The external terminal 7 is attached to the three-layered sealing board. It is attached with rivets. 12 indicates an explosion-proof hole.

FIG. 3 shows an electrolytic capacitor constructed using the sealing plate shown in FIG. The open end of the case 9 is tightened and sealed with rubber 11.

The electrolytic capacitor of the present invention is constructed as described above, in which both the front and back sides of the hard insulating plate 10 are covered with organic synthetic rubber 11, and the substrate is covered with organic synthetic rubber laminated on one side. Since the external terminals are attached to the sealing plate with rivets, even if used continuously at high temperatures for long periods of time, there will be no airtight failure at the rivet attachment part of the sealing plate or at the circumferential edge of the sealing plate. And no corrosion occurs. Since the sealing plate is made of two materials, the hard insulating plate 10 and the organic synthetic rubber 11, it has advantages such as being able to be produced at low cost and being mass-producible.

In addition, in the above-mentioned embodiment, the explosion-proof hole 12 and
An explosion-proof valve can be constructed with the organic synthetic rubber 11 on the front surface, the organic synthetic rubber 11 on the back surface, or the organic synthetic rubber 11 on both surfaces, and can be designed as desired, such as by providing an explosion-proof mechanism in the case.

As mentioned above, the electrolytic capacitor obtained by the manufacturing method of the present invention has great industrial and practical value, as it has high airtightness, does not corrode, is extremely reliable, and can be manufactured at low cost.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a conventional electrolytic capacitor, Figure 2 is a cross-sectional view of a conventional electrolytic capacitor.
The figure is a sectional view of the sealing plate of the electrolytic capacitor of the present invention.
FIG. 3 is a sectional view of an embodiment of the electrolytic capacitor of the present invention. 1: Drawer lead plate, 2: Capacitor element, 7:
External terminal, 9: Case, 10: Hard insulation board, 1
1: Organic synthetic rubber.

Claims (1)

[Claims] 1 Sealing with a three-layer structure in which the front, back, and side surfaces of a hard insulating board such as Bakelite or polypropylene are coated with organic synthetic rubber made of ethylene propylene polymer or isoprene, and the side surface of the substrate is covered with organic synthetic rubber that is bonded to one side. External terminals are placed on the board, the organic synthetic rubber layer on the top surface of the sealing board and the organic synthetic rubber layer on the bottom surface are compressed and airtightly attached with rivets, and a drawer lead board is drawn out from the rivets and the capacitor element. A method for manufacturing an electrolytic capacitor, comprising: connecting the above-mentioned sealing plate to an opening of a case, and then tightening the case to seal it.