JPS605217B2 - Low impedance aluminum rectangular electrolytic capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to aluminum electrolytic capacitors, and more particularly to this type of electrolytic capacitor which has low impedance and is easy to manufacture.

Since the recent development of switching regulators, electrolytic capacitors have been used at high frequencies. Demand is increasing.

Conventionally, in order to obtain an electrolytic capacitor with good frequency characteristics and low ESR, it was done to use an electrolytic solution with low resistivity, use low-density electrolytic paper, and increase the number of tabs drawn out from the electrode foil. .

However, increasing the number of drawer tabs increases the number of manufacturing steps and makes it difficult to wind the capacitor element, and economically it has not been possible to increase the number of drawer tabs much. On the other hand, as various electronic circuit components become smaller, electrolytic capacitors that can be made smaller and have higher packaging density are desired. Therefore, an object of the present invention is to provide an electrolytic capacitor that has low impedance, is easy to manufacture, and is small.

The present invention manufactures a wound-type small-capacity unit capacitor element in which an anode tab and a cathode tab are pulled out one by one in opposite directions, and a predetermined number of the unit capacitor elements are equipped with negative and positive terminals. The respective anode and cathode tabs are connected to the anode and cathode terminals by closely arranging them in parallel with each other on an indestructible substrate having two strip-shaped conductor plates connected to and supported by the terminal plate. This electrolytic capacitor is characterized in that it is connected to and supported by band-shaped conductor plates that follow each of the conductor plates, and is sealed with an insulating substrate by covering the rectangular case with the rectangular case.

Hereinafter, the present invention will be explained in detail with reference to embodiments shown in the drawings.

Referring to FIG. 1, anode foils 1 and cathode foils 2 made of aluminum are alternately stacked on electrolytic paper 3, and this is wound.

At this time, one anode tab 4 and one cathode tab 5 are each pulled out from the anode foil 1 and the cathode foil 2, and they are pulled out to opposite sides. Note that the tap and the foil are connected by mechanical crimping or spot welding as in the past.
A perspective view of the capacitor element 6 obtained by winding is shown in FIG. Using this capacitor element 6 as a unit element, a plurality of the capacitor elements 6 are used to construct a capacitor of a desired capacity.

Therefore, the capacitance of the unit element 6 is selected to be 4 times smaller than the target capacitor capacitance. Referring to FIG. 3, a plurality of unit elements 6 (five in the figure) are closely arranged in parallel, and the anode tab 4 of each unit element is spotted onto one strip-shaped conductor plate (for example, an aluminum plate) 7. They are joined by welding or mechanical crimping, and similarly each unit element is joined to one strip-shaped conductor plate 8 having a cathode tube 5, thereby constructing a capacitor element of a desired capacity.

On the other hand, as shown in FIGS. 4 and 5, a substrate 11 having a pair of anode terminals 9 and a pair of cathode terminals 10 is prepared, and the capacitor element shown in FIG. 3 is placed on this,
The strip-shaped conductor plate 7 on the anode tab side is connected and fixed to a pair of anode terminals 9 by mechanical crimping or spot welding, while the strip-shaped conductor plate 8 on the cathode tab side is connected to the cathode terminal 10 in the same manner. , connect and fix.

In this way, a capacitor main body is obtained in which a plurality of unit elements are closely arranged in a plane on the substrate 11, and the anode terminal and the cathode terminal are made to protrude from the back side of the substrate.

Note that the terminals may be connected in pairs as shown in the figure, or
One yang is fine.

Moreover, as for the manufacturing process order, the strip-shaped conductor plate may be attached to the terminals on the substrate in advance, and then the unit elements may be attached to the strip-shaped conductor plate. As shown in FIG. 5, a rectangular case 12 is placed over the capacitor body, and its closed edge is sealed to the edge of the substrate 11 to obtain an electrolytic capacitor.

Note that the substrate 11 may be an insulating plate (for example, a resin plate), or may be one insulating plates 112 bonded to the upper and lower surfaces of an aluminum plate 111, leaving the periphery as shown in FIG.

In this case, as a matter of course, in order to insulate each terminal 9, 10 from the aluminum plate 111, the aluminum plate 1
Needless to say, it is necessary to provide an insulating material in the terminal through hole 11.

The case 12 may be an insulator or a conductive plate such as aluminum.

According to the above-described configuration, the unit element can be manufactured in exactly the same manner as a conventional wound type capacitor, and the subsequent manufacturing process requires only a bonding operation, so that the manufacturing operation is extremely simplified.

Furthermore, as a whole, this is equivalent to having as many tabs as the number of unit elements drawn out from each of the positive and negative electrodes, and the impedance can be significantly lowered. FIG. 6 shows frequency-impedance characteristics of a conventional electrolytic capacitor and an electrolytic capacitor according to the present invention in order to show the effect of lowering impedance according to the present invention.

In the figure, curve a shows the conventional type, and curves b and c are based on the present invention, where b shows the case of two terminals and c shows the case of four terminals. As understood from FIG. 6, it is clear that according to the present invention, low impedance is achieved.

Further, according to the present invention, since small-capacity unit elements are arranged in a planar manner, a thin and rectangular electrolytic capacitor can be obtained, so that the packaging density in a circuit device can be improved.

[Brief explanation of drawings]

FIG. 1 is a developed view of a unit element according to the present invention, FIG. 2 is a perspective view of the unit element, FIG. 3 is a perspective view showing a capacitor element in which a plurality of unit elements are combined, and FIG. Figure 5 is a top view of the capacitor element arranged and fixed on the board.
FIG. 6 is a cross-sectional view of the completed capacitor with a case, and is a graph showing impedance-frequency characteristics. 1... Anode foil, 2... Cathode foil, 3...
... Electrolytic paper, 4 ... Anode tab, 5 ...
Cathode tab, 6... Unit element, 7, 8...
・Strip-shaped conductor plate, 9...Anode terminal, 10...Cathode terminal, 1 1...Substrate, 12...Case, a
...Conventional product, b...2-terminal product according to the present invention, c...4-terminal product according to the present invention. Figure 1 Figure 2 Figure 3 Sabamu Figure 5 Figure 6

Claims (1)

[Claims] 1. A plurality of capacitor unit elements each having an anode terminal and a cathode terminal, each having an anode terminal and a cathode terminal, each of which has an anode terminal and a cathode terminal. On an insulating substrate having two strip-shaped conductor plates connected to both terminals and supported parallel to each other, each anode tab is bonded to the strip-shaped conductor plates connected to the anode terminals. and each of the cathode tabs is joined to a band-shaped conductor plate connected to the cathode terminal and arranged closely in parallel with each other, and a rectangular case covering the cathode tab is sealed to the insulating substrate. A low impedance aluminum rectangular electrolytic capacitor.