JPS6013295B2 - Block type electrolytic capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a block type electrolytic capacitor, and in particular provides a block type electrolytic capacitor having excellent performance as an acoustic capacitor.

In general, capacitors used in audio equipment are designed specifically for acoustic use because it is necessary to faithfully reproduce audio signals, and their performance is as follows:
It has low impedance over a wide frequency band (DC to IMHz), has a sufficiently low distortion rate as a single unit, and generates little leakage flux when incorporated into a circuit, and has a low distortion rate as an audio device. Characteristics such as those that do not affect the performance are required. For example, aluminum electrolytic capacitors used for smoothing the power supply of stereo signal amplifiers are used not only to supply power to the amplifier, but also as part of the signal path. It is required that the power source impedance with respect to the following ability and frequency be sufficiently low and flat.

In particular, the power supply supplied to the final stage of a power amplification amplifier handles a large current, and changes in load current due to sudden changes in signals are large. It becomes a problem. Furthermore, the increase in impedance at high frequencies is due to the inductance component, and if the inductance component is large, there is a risk that it will not be possible to cope with rapid current changes. Therefore, many studies have been made to reduce the inductance component and improve the characteristics of aluminum electrolytic capacitors used for applications requiring high frequency performance, including acoustic applications. For this reason, with aluminum electrolytic capacitors that have a structure in which conventional strip-shaped electrode foil is wound, ``Although it is not possible to completely eliminate the inductance component, by adjusting the height and number of lead-out leads, it hardly poses a problem in practice.'' It was possible to improve the characteristics to the standard, achieving low impedance to flatness up to high frequencies.

For example, as shown in FIG.
Rather than pulling out from the edge, by pulling out from the center as shown in Figure 2, or pulling out multiple pieces as shown in Figure 3,
As shown in Figure 4, the frequency characteristics can be significantly improved, but in this case, unless the tension and tightening conditions are adjusted extremely strictly, it will be difficult to pull out the lead from a certain position, resulting in poor production efficiency. Therefore, it was not a good idea from an industrial perspective.

If a large number of leads do not come out from a fixed position, the anode lead and the cathode lead may cross each other, causing a short circuit failure, which is unacceptable. Note that in FIG. 4, characteristics A, B, and C are frequency characteristics corresponding to FIGS. 1, 2, and 3, respectively. Therefore, in order to actually industrially produce a product with such an effect, it is necessary to make a small capacity aluminum electrolytic capacitor with a single intermediate lead, which has the simplest structure and is easy to manufacture, and connect it in parallel. It is thought that it is better to connect it to a block and create a block.

Conventionally, in order to realize this idea and to make the actual work easier, a method was used in which a small-capacity, free-standing capacitor was attached to a printed wiring board that also served as a lid for the entrance of the outer case. was.

However, in this method, the internal capacitor element is first housed in a cylindrical aluminum case, and then this is made into a block and housed in the outer case, so there is a double space between it and the outermost case. Therefore, it has the disadvantage of being large in size as a block electrolytic capacitor. Furthermore, even though the internal element has the appearance of an electrolytic capacitor, it is housed in an external case again, which is a problem from a cost performance standpoint. The present invention was developed in view of these problems, and by covering a small capacity aluminum electrolytic capacitor element housed in an exterior case with a composite film having excellent heat resistance,
It is possible to store the capacitor element in a shape that is more efficient for the outer case capacity, such as a bird's-eye shape, and eliminates unnecessary voids. The dimensions can be reduced by 30% L, and by eliminating the aluminum case and terminal board, the price can also be significantly reduced.

Hereinafter, the block type electrolytic capacitor according to the present invention will be explained using the drawings of FIGS. 5 to 10. Figure 5~
FIG. 9 shows a block type electrolytic capacitor according to an embodiment of the present invention. This capacitor unit 11 is a capacitor unit that is housed in parallel.As shown in Figures 8 and 9, this capacitor unit 11 has a separator impregnated with electrolyte between the electrode foils made of aluminum. An ionomer resin film 13a and a polyester film 13 are placed on both sides of a metal film 13b such as aluminum so that the ionomer resin film 13a is on the inside.
The grooves are formed by sealing and packaging with an exterior film 13 laminated with the exterior film 13, and the lead leads 14a and 14b on the anode and cathode sides connected to the electrode foil of the capacitor element 12 are connected to the overlapping portion of the exterior film 13. It is mechanically held by the thermocompression bonded portion 15 of the exterior film 13 and pulled out.

In addition, in this embodiment, as the structure of the exterior film 13, the outermost layer is a polyester film 13c with a thickness of 12 layers.
As the metal film 13b, an aluminum film with a thickness of 15 ridges was used, and as the ionomer resin film 13a, a 30mm thick "Surlyn" (trade name) manufactured by DuPont, USA was used. Further, as the conditions for thermocompression bonding the circumferential portion of the exterior film 13, a good sealing state can be obtained by thermocompression bonding at a temperature of 150 to 170 pm. Here, the ionomer resin used in the exterior film 13 is a polymer in which Q-olefin chains and Q.8 unsaturated carboxylic acid are interchain-crosslinked with metal ions, and "ion dissociates when heated and melted, and when cooled and solidified, It has thermoreversibility to crosslink again.

Further, the condenser unit 1 1 has the resin case 1
0, and is mechanically held and housed by attack polypropylene 16. 17 is the resin case 1
This is an insulating terminal board disposed so as to close the opening of the capacitor unit 11.
Flat anode and cathode conductive plates 18a and 18b made of non-magnetic material are arranged in parallel to which the anode and cathode lead leads 14a and 14b are respectively connected, and the conductive plate 18a
, 18b are provided with external terminals 19a, 19b standing upright.

20 is an attack polypropylene filled on this terminal plate 17, and 21 is an epoxy resin filled on this attack polypropylene 20. These epoxy resin 21, attack polypropylene 20, and terminal plate 17 make the resin case 10 A seal is in place.

Incidentally, in this embodiment, a plurality of flat capacitor units 11 are housed in the resin case 10, and the plurality of capacitor units 11 are connected in parallel to each other by the terminal plate 17. In this case, the shape of the capacitor unit may be selected to suit the shape of the resin case 10 so that it fits well.

Comparing the product of the present invention with a rating of 90 V and 22,000 French F made in this manner with the conventional product, the volume ratio is 3.
The product of the present invention can be made smaller by 0% or more.

Also, when comparing the frequency characteristics of impedance, the first
As shown in Figure 0, remarkable effects can be obtained. In FIG. 10, characteristic A is the conventional product, characteristic B is the characteristic of the present invention according to the above embodiment, and characteristic C is the characteristic of the present invention divided into 12 capacitor units. In this way, the block type electrolytic capacitor according to the present invention has a distortion rate (1 plate H
Measurement of the 3rd harmonic at
, 22,000 French F) was -8th generation old, while 11th generation
4 can be significantly improved over the old version.

Furthermore, ``Generally, leakage of magnetic flux that occurs when current flows through a conductor affects the audio signal as noise, so various measures have been taken to reduce this. The lead from the electrolytic capacitor to the external terminal is carried out not by a wire but by a plane, that is, by a conductive plate made of a flat non-magnetic material, and the magnetic flux can be reduced to 1/10 of that of conventional products. As described above, according to the present invention, compared to forming a block out of an outer bag with a metal case, it is possible to reduce the size by more than 30% with the same rating, and it is also cheaper.
Moreover, since it is possible to divide into very fine parts, it is easy to obtain products with ultra-low impedance that are suitable for high-frequency applications such as audio equipment and switching regulators, which particularly require good frequency characteristics and low leakage flux. You can get the desired effect.

[Brief explanation of the drawing]

Figures 1 to 3 are plan views showing the lead extraction structure of conventional electrolytic capacitors, and Figure 4 is the first
The frequency characteristics of impedance in an electrolytic capacitor using the lead extraction structure shown in Figs. 5 is a cross-sectional view taken along line A-A' in FIG. 5, FIG. 7 is an exploded perspective view showing the main structure of the same capacitor, and FIGS. 8 and 9 are perspective views showing an example of a capacitor unit used in the same capacitor. diagrams and cross-sections;
FIG. 10 is a frequency characteristic diagram showing a comparison of impedance changes between a block type electrolytic capacitor according to the present invention and a conventional product. 10...Resin case, 11...Condenser unit, 1
2... Capacitor element, 13... Exterior film, 13a... Ionomer resin film, 13
b...Metal film, 13c...Polyester film, 14a, 14b...Drawer lead, 17
...Terminal board, 18a, 18b... Conductive plate. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure T Figure 9 Figure 10 Figure 8

Claims (1)

[Scope of Claims] 1. An exterior case, a plurality of capacitor units housed in parallel in this exterior case, and configured by pulling out capacitor elements to the outside, pulling out leads, and sealing the capacitor units with an exterior film; It has a conductive plate to which the drawer leads of a plurality of capacitor units are electrically connected, and a terminal plate disposed in the opening of the outer case, and the conductive plate is attached to the upper surface of the terminal plate. A block type electrolytic capacitor characterized in that the plurality of capacitor units are connected in parallel by a conductive plate. 2. The block type electrolytic capacitor according to claim 1, wherein the outer film is a laminate of at least two types of films including an ionomer resin film. 3. The block type electrolytic capacitor according to claim 1, wherein the conductive plate is made of a non-magnetic material.