JPS6325729Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electrolytic capacitor with improved impedance characteristics at high frequencies.

The structure of a conventional oval electrolytic capacitor is as shown in Fig. 1A, in which a lead plate 1 is connected to two electrode foils, and a capacitor element 2 is wound with electrolytic paper interposed therebetween.
₁ into a flat capacitor element ₂ as shown in FIG.
Thereafter, as shown in FIG. 2, the drawer lead plate 1 and the terminal fixed to the sealing plate 4 are connected, inserted into a case 5 made of aluminum or the like, and the capacitor element ₂ is fixed with a filler 6. , the opening of the case 5 is sealed tightly.

However, in the above-mentioned structure, since the capacitor element 2 ₂ is formed by deforming the cavity in the winding axis direction of the capacitor element 2 ₁ into a flat shape, tension and friction are generated in the electrode foil during deformation, damaging the oxide film. This causes many problems, such as increasing leakage current, loosening the flat parts of the hollow cylinder, increasing capacitor loss and impedance, and requiring a clamping frame, which requires time for assembly. There were flaws.

The present invention was devised to eliminate the above-mentioned drawbacks, and provides an electrolytic capacitor that is easy to assemble and has excellent impedance characteristics.

Hereinafter, the present invention will be explained with reference to the embodiment shown in Figs. 3 to 7. Fig. 3 is an exploded perspective view of the main part of a capacitor element, and the surface is chemically treated to approximately 2/3 of the length without etching. An electrode foil 9 is ultrasonically connected to each of the two aluminum plates 7 which have been subjected to the above treatment, and is wound around the aluminum plate 7 through a separator 10 such as electrolytic paper to form an oblong capacitor element 11 as shown in FIG. form. The electrode foil 9 is an etched electrode foil, and the anode side is further chemically treated. 8 is a chemical conversion treatment section. Next, the capacitor element 11 is impregnated with an electrolytic solution and inserted into a case 13 made of aluminum or the like, the capacitor element 11 is fixed with a filler 6, and the capacitor element 11 is sealed with a sealing plate 12 provided with a through hole through which the aluminum plate 7 passes. After the opening of the case 13 is sealed, the gap between the aluminum plate 7 and the sealing plate 12 is filled with resin or the like and sealed. Finally, the aluminum plate 7
Open the upper end part to the left and right to form the terminal 15.
It will be completed as shown in the figure.

Note that since it is necessary to insulate the opposing surfaces of the aluminum plate 7, the aluminum plate 7
and an electrode foil 9 connected to the aluminum plate 7
When the capacitor elements 11 and 11 are stacked on top of each other with a separator 10 in between, insulation is achieved by applying an insulating resin to the facing surfaces 14 of the aluminum plate 7 on the upper part of the capacitor element 11 or pasting plastic tape on them.

The present invention is constructed as described above, in which two aluminum plates 7 are parallel to each other, closely facing each other with an insulating material such as the above-mentioned insulating resin or plastic tape interposed therebetween, and the aluminum plates 7 Since the capacitor is formed by winding an electrode foil and a separator around the capacitor, a low impedance capacitor (first capacitor) is formed by two adjacent parallel aluminum plates 7 and an insulating material interposed between them. Form. The aluminum plate 7 becomes the winding axis of the capacitor element 11, and a second capacitor is formed by the wound electrode foil and separator.
Therefore, there is no step of deforming the capacitor element 11 into a flat shape, and no tension or friction is generated in the electrode foil, so leakage current does not increase and assembly is simplified. Furthermore, since the above-mentioned low impedance capacitor is formed by extending two opposing aluminum plates 7 and forming the capacitor through a sealing plate, the inductance is canceled out and the impedance characteristic is greatly improved.

In the above example, both of the two aluminum plates 7 are subjected to chemical conversion treatment, but if only the anode side is subjected to chemical conversion treatment, the capacitance between the opposing aluminum plates increases and the size can be made smaller.

FIG. 6 is a plan view of a capacitor element showing another embodiment of the present invention, in which a bent portion 7a is formed by bending at least one side edge of opposing aluminum plates 7. The electrode foil is connected by ultrasonic welding as shown in Figure 3.
When wrapped around the electrode foil, the aluminum plate 7
The leakage current of the capacitor can be further reduced by smoothing the bend at the point where it contacts the end of the capacitor.

Next, as an example of this invention, the rating is 63WV,
An 18000μF electrolytic capacitor was manufactured, and the impedance-frequency characteristics compared with a conventional product are shown in Figure 7. As is clear from the figure, the product of the present invention exhibits low impedance at high frequencies and exhibits the above-mentioned effects.

As mentioned above, the present invention is an electrolytic capacitor that is easy to assemble, has low leakage current, and has greatly improved impedance characteristics.It expands the usable frequency band and its uses, and has industrial and practical value. It is a big thing.

[Brief explanation of drawings]

Figure 1 is a perspective view of a conventional electrolytic capacitor element, A is before flattening, B is after flattening, Figure 2 is a cross-sectional view of a completed electrolytic capacitor using the capacitor element in Figure 1, Figure 3 is an exploded perspective view of essential parts of an electrolytic capacitor element according to an embodiment of the present invention, Figure 4 is a perspective view of the electrolytic capacitor element of Figure 3, and Figure 5 is a completed diagram of the electrolytic capacitor element of the present invention. is a plan view, b is a cutaway front view of main parts, c is a side view, and
The figure is a plan view of a main part of an electrolytic capacitor element according to another embodiment of the present invention, and FIG. 7 is an impedance-frequency characteristic diagram of an electrolytic capacitor comparing the product of the present invention and a conventional product. 7... Aluminum plate, 7a... Bent part,
8... Chemical conversion treatment section, 9... Electrode foil, 10... Separator, 15... Terminal.

Claims (1)

[Claims for Utility Model Registration] (1) An insulating material is interposed between two closely facing parallel aluminum plates whose surfaces are not etched and at least one side has undergone chemical conversion treatment. An electrolytic capacitor comprising a first capacitor formed and a second capacitor formed by connecting an etched electrode foil to the aluminum plate and winding the aluminum plate through a separator. (2) An electrolytic capacitor as set forth in claim 1 of the utility model registration claim, in which an extended end of the aluminum plate is used as a terminal of the capacitor. (3) The electrolytic capacitor according to claim 1, which is obtained by bending at least one side edge of the aluminum plate.