JPS5934120Y2 - Low impedance thin electrolytic capacitor - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an ultra-thin aluminum electrolytic capacitor that is mounted in an ultra-thin power supply such as a switching regulator.

Ever since high-efficiency switching regulators were developed to replace series regulators, aluminum electrolytic capacitors used in smoothing circuits have good frequency characteristics and L (axial length of wound capacitor element) dimensions. There is a growing demand for something short and easy to implement.

Recently, switching regulators have become thinner and thinner, and the thickness has been reduced to around 3Q mm.

The electrolytic capacitor mounted on this has a L dimension of 3Q mm.
or the diameter is required to be 30 mm or less.

Recently, in response to the above-mentioned requirements, cylindrical electrolytic capacitors having a dimension L smaller than the diameter (D>L) have been developed.

However, the L dimension is low at around 10 to 20 mm, and the cut
Electrolytic capacitors with a large product of 100,000 to 500,000 (μF-vOH) had the disadvantage that cylindrical electrolytic capacitors had been developed, and the frequency characteristics worsened as the L dimension became larger than the 9 dimension.

In response to the above-mentioned requirements, the present invention has developed a
Moreover, it is an object of the present invention to provide a thinner electrolytic capacitor.

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

FIG. 1 is a developed view of an electrolytic capacitor element, in which 1 is an anode foil, 2 is a wide anode tab attached to the anode foil 1 by mechanical compression, 3 is a cathode foil, and 4 is attached to the cathode foil 3. It is a wide cathode tab and is attached so as to be pulled out in the opposite direction to the anode tab 2.

5 is an electrolytic paper inserted between the anode foil 1 and the cathode foil 3.

The wide positive and cathode tabs 2 and 4 in Figure 1 are installed with four each, but if the number of tabs is n, the equal series resistance (ESR) is inversely proportional to n, so the larger the number of tabs, the greater the number. However, in this invention, as electrolytic paper, kraft paper, manila paper, etc. with a density of 0.3 to 0.
．． Use an electrolyte with a specific resistance of about 8 and a specific resistance of 100.
When using a material with a resistance of ~500 Ω·cm, it has been found that the number n of tabs is approximately 23 to 5, economically and in terms of characteristics.

Furthermore, although the positive and negative electrode tabs 2 and 4 may be attached at any appropriate position, it is better to attach the positive and negative electrode tabs at positions that face each other as much as possible.

FIG. 2 shows an element 6 obtained by winding the element shown in FIG. 1 using a winding core having a relatively large diameter of 5 mm or more, and then flattening the winding.

The anode tab and cathode tab are each stacked,
It is also approximately equal to its width.

To directly attach external electrode terminals to the wide positive and negative electrode tabs 2 and 4 protruding from both ends of the flattened element 6, holes 7 to 10 are formed by a burring method or the like.

This is shown in FIG.

FIG. 4 shows a rectangular sealed terminal plate 11.

12.13 and 14.15 indicate positive and negative rivets molded on the rectangular sealed terminal plate 11.

The material of the rectangular sealed terminal plate 11 is polyester resin, polypropylene resin, etc., which can be ultrasonically welded.

FIG. 5 shows a side view of FIG. 4.

In the figure, 17 indicates an anode external terminal, and 18 indicates a cathode external terminal.

FIG. 6 shows an assembly diagram in which the flattened element 6 shown in FIG. 3 is attached to a rectangular sealed terminal plate 11.

For mounting rivets formed on the wide anode tab 2 protruding from the flattened element 6, the holes 7 and 8 are connected to the anode rivets 12.1.
3, and the rivet mounting molded into the wide cathode tab 4 is attached to the cathode rivets 14 and 15 in holes 9 and 10.

It can be easily installed using the conventional caulking method.

Figure 7 shows polyester resin, a resin that can be ultrasonically welded.
This is a square resin case 20 made of polypropylene resin or the like.

Reference numeral 21 indicates an explosion-proof hole provided in the square resin case 20.

FIG. 8 shows a completed thin prismatic electrolytic capacitor using the prismatic resin case 20 of FIG. 7.

The rectangular sealed terminal plate 11 and the rectangular case 20 are joined by ultrasonic bonding at a collar provided on the rectangular case 20.

. When using a rectangular case without a flange, the rectangular sealed terminal plate 11 and the rectangular case 20 shown in FIG. 9 are used, and the contact portion between the rectangular sealed terminal plate 11 and the rectangular case 20 is bonded by ultrasonic waves.

The thin rectangular electrolytic capacitor according to the present invention is easy to mount in ultra-thin power supplies such as ultra-thin switching regulators, and can be externally mounted with 4 terminals, including an anode and a cathode.
Since there are several locations, even large-capacity electrolytic capacitors do not require legs to be mounted, unlike conventional methods, and are particularly easy to mount.

As shown in FIG. 10, the method of using the electrolytic capacitor according to the present invention is as shown in FIG.
Furthermore, the two cathode external terminals 18 and 19 are shared and used as a two-terminal electrolytic capacitor.

In addition, as shown in FIG. 11, two positive and negative external terminals 1
6°18 on the input side, and the other two positive and negative external terminals 17.
By connecting 19 to the output side, it can also be used as a 4-terminal electrolytic capacitor.

FIG. 12 shows impedance vs. frequency characteristics.

It can be seen that the device b according to the present invention has better frequency characteristics than the conventional device a.

[Brief explanation of the drawing]

Fig. 1 is a developed view of the capacitor element, Fig. 2 is a perspective view of a flattened capacitor element, Fig. 3 is a plan view of the capacitor element with mounting holes, Fig. 4 is a perspective view of the sealed terminal plate, and Fig. 5 is a perspective view of the capacitor element. The figure is a side view of the sealed terminal plate, Figure 6 is a side view of the capacitor element attached to the sealed terminal plate, Figure 7 is a perspective view of the square case, Figure 8 is a cross-sectional view of the completed electrolytic capacitor, Figure 9 is a sectional view of another embodiment, Figures 10 and 11.
The figure is a circuit diagram showing different usage examples, and FIG. 12 is a graph showing impedance vs. frequency characteristics. 1...Anode foil, 2...Anode tab, 3.
...Cathode foil, 4...Cathode tab, 5...
... Electrolytic paper, 6 ... Flat capacitor element, 1
1...Sealing terminal plate, 16.17...Anode external terminal, 18.19...Cathode external terminal, 2
0... Square case, 21... Explosion proof hole.

Claims (1)

[Scope of utility model registration request] A flat capacitor element in which an anode foil, a cathode foil, and an electrolytic paper are layered and rolled and then pressed in the radial direction to flatten them, and an anode tab and a cathode tab with a wide width approximately equal to the width of the flat capacitor element are formed. A flat capacitor, each having at least three sheets and stacked with the anode tab protruding to one side of the capacitor element and the cathode tab protruding to the other side, is stacked on the substrate having the anode terminal and the cathode terminal. The anode tab and cathode tab are fixed in position by connecting and fixing them to the anode terminal and cathode terminal, respectively, and an explosion-proof rectangular case is placed over the anode tab and cathode tab, which is sealed to the substrate. Thin electrolytic capacitor.