JPS5930532Y2 - Electrolytic capacitor - Google Patents

Description

[Detailed description of the invention] The present invention relates to an electrolytic capacitor that uses two conductive plates that cross electrically independently of each other, and in particular improves the sealing of the opening of the case to provide a highly stable and low-temperature capacitor with good sealing performance. This is to obtain an electrolytic capacitor of impedance.

Recently, control systems that use high frequencies, such as switching DC power supplies, have come into widespread use, and the electrolytic capacitors used in the filter circuits and smoothing circuits of such power supplies operate satisfactorily in the high frequency range. possible,
Low equal series resistance and low equal series inductance are required.

In order to meet these demands, low impedance electrolytic capacitors shown in FIGS. 1 and 2 have been developed.

The electrolytic capacitor shown in FIGS. 1 and 2 uses four capacitor elements 3 each having one anode lead 1 and one cathode lead 2, and the anode lead 1 and cathode lead 2 of the capacitor elements 3 are made of aluminum or the like. It is made of conductive metal and is enclosed in a case 6, connected to an anode terminal plate 4 and a cathode terminal plate 5, which are electrically independently crossed with each other.

Although this capacitor fully satisfies the above-mentioned performance requirements, as shown in FIGS. It penetrates through the cross-shaped through hole 8 and protrudes to the outside, and the penetrating portion is fixed and sealed with thermosetting resin such as epoxy resin, so the penetrating portion has poor airtightness and cannot be exposed to high temperatures for long periods of time. When carrying out load tests, the electrolyte dried out, causing problems such as a decrease in capacity and an increase in loss.

In addition, since the connecting parts 4 a , 4 b , 5 a , and 5 b that protrude to the outside of the anode terminal plate 4 and the cathode terminal plate 5 protrude above the sealing body 7 , the mechanical strength of the protruding parts is weak and is not suitable for practical use. There was a problem above.

To solve this problem of mechanical strength, as shown in FIG. 3, the thickness of the sealing body 7 is increased, and the connecting parts 4 a , 4 b , 5 a , which protrude to the outside of the anode terminal plate 4 and the cathode terminal plate 5 ,
Although this problem could be solved by making the outer surface of the sealing member 7 and the outer surface of the sealing member 7 on the same plane, the problem of airtightness was not yet solved.

The present invention is intended to solve such problems, and will be described below with reference to FIGS. 4 and 5, which show an embodiment of the present invention.

In the figure, reference numeral 11 denotes a cylindrical metal case with a bottom, and inside this metal case 11, four capacitor elements 14 each having one anode lead 12 and one cathode lead 13 pulled out are housed impregnated with electrolyte. be done.

This condenser element 14 is made by winding an anode foil and a cathode foil made of a valve metal such as aluminum with a separator in between.
It is constructed by pulling out one anode lead 12 and one cathode lead 13, respectively.

15 is a conductive plate made of conductive metal such as aluminum;
This conductive plate 15 consists of an anode conductive plate 16 and a cathode conductive plate 17, and the anode conductive plate 16 and the cathode conductive plate 17 are electrically separated from each other by slits 18 and 19 provided from their ends to the middle. The anode lead 12 and the cathode lead 13 of the capacitor element 14 are connected to the anode conductive plate 16 and the cathode conductive plate 17, respectively.

Further, the ends of the anode conductive plate 16 and the cathode conductive plate 17 on the opening side of the metal case 11 are bent at right angles to form connecting portions 16 a , 16 b , 17 a , 17 b .
is configured, and its connecting portions 16 a and 16 b
, 17 a , and 17 b are provided with through holes 20 .

Reference numeral 21 denotes a disc-shaped sealing body for sealing the opening of the metal case 11, and the sealing body 21 has anode terminals 22 a and 2 with rivets made of a conductive metal such as aluminum.
2 b and cathode terminals 23 a and 23 b are buried at predetermined intervals with their tips protruding from both end faces, and an explosion-proof valve 24 is provided in the center of the sealing body 21 .

Anode terminals 22 a , 22 embedded in this sealing body 21
b and cathode terminals 23 a and 23 b are inserted into the sealing body 2 by insert molding when the conical sealing body 21 is shaped.
1.

In addition, the anode terminals 22a, 22b and the cathode terminal 23
a, 23b, connecting portions 16a, 16b of the anode conductive plate 16 and connecting portion 17a of the cathode conductive plate 17, respectively.
, 17b are connected to these connecting portions 16 a, 16 b, 1
7 a, 17 b (7) Joined in the through hole 20 by mechanical compression, welding, or a combination thereof.

Figure 5 shows this joined state.

Here, the anode terminals 22 a , 22 of the sealing body 21
b and cathode terminals 23a, 23b with anode conductive plate 1
6. Connect the cathode conductive plates 17, and connect the capacitor element 14 to the anode conductive plate 16 and cathode conductive plate 17, respectively.
Connect the cathode lead 12 and the cathode lead 13 respectively,
The capacitor element 14 is impregnated with an electrolytic solution and housed in the metal case 11, and the periphery of the opening of the metal case 11 is curled, drawn, etc. to create a gap between the sealing body 21 and the periphery of the opening of the metal case 11. By sealing, an electrolytic capacitor according to the present invention is constructed.

Next, we will introduce the conventional electrolytic capacitor (a) shown in Figure 1 and the fourth
The results of an experiment regarding the rate of change in capacitance (solid line in Figure 6) and change in loss (tan δ) (dotted line in Figure 6) with respect to time with respect to the electrolytic capacitor port of the present invention shown in Figure 5 and Figure 5 are shown below. This will be explained based on FIG.

In both cases, an electrolytic solution consisting of ethylene glycol and ammonium adipate was used as a driving electrolytic solution, and the rated voltage was 10 V, 100,000 μF, and a DC rated voltage was applied at a temperature of 85° C..

As is clear from the characteristics shown in Figure 6, the capacitance and loss (tan δ) of the conventional electrolytic capacitor significantly increase after 1000 hours at a temperature of 85°C. On the other hand, the electrolytic capacitor according to the present invention has little change in capacitance and has low loss (tan δ).
) are also few.

Further, after 2000 hours, there was no particular change in appearance between the conventional one and the one of the present invention, but the electrolyte of the conventional one had dried considerably.

In comparison, in the case of the present invention, drying of the electrolyte solution did not occur at all.

In other words, the electrolytic capacitor of the present invention has an incomparably improved sealing performance compared to conventional capacitors.

Generally speaking, even with conventional electrolytic capacitors, it is often thought that problems with sealing performance can be solved if the anode terminal plate and cathode terminal plate are placed at the same time when molding the sealing body. This structure is not compatible with general electrolytic capacitors that are currently mass-produced, and therefore is extremely expensive in terms of molding and other aspects, making it impractical.

In comparison, the electrolytic capacitor of the present invention can be used in common with the sealing bodies of currently mass-produced electrolytic capacitors, making it extremely practical and extremely effective in reducing costs and the number of parts. .

As described above, since the electrolytic capacitor of the present invention uses a conductive plate consisting of an anode conductive plate and a cathode conductive plate that cross each other electrically independently, it can be used in high frequency ranges with low equal series resistance and equal series inductance. In addition, the opening of the case that houses the capacitor element is sealed with a sealing body that has four terminals that are connected to the conductive plate on the inside of the case, further improving the sealing performance of the case. This does not cause deterioration of characteristics such as a decrease in capacitance or an increase in loss, and is also very practical from the perspective of reducing costs and the number of parts. , has high industrial value.

[Brief Description of the Drawings] Figures 1 and 2 are exploded perspective views of a conventional electrolytic capacitor, Figure 3 is a perspective view showing another example of the main parts of the same capacitor, and Figure 4 is an exploded perspective view of a conventional electrolytic capacitor. An exploded perspective view of an electrolytic capacitor according to an embodiment, FIG. 5a is a plan view of the main parts of the same capacitor, FIG. 5 is a side view thereof, and FIG. FIG. 3 is a characteristic diagram showing the capacitance change rate and the change in loss tan δ) with respect to the capacitance. 11... Metal case (case), 12...
...Anode lead, 13...Cathode lead, 14.
... Capacitor element, 16 ... Anode conductive plate, 17 ... Cathode conductive plate, 18.19 ...
...Slit, 2... Sealing body, 22 a, 2
2 b...Anode terminal (terminal), 23 a, 2
3 b...Cathode terminal (terminal).

Claims (1)

[Scope of utility model registration request] An anode conductive plate and a cathode conductive plate are combined so that they cross each other electrically independently through a slit provided from their ends to the middle, and a plurality of capacitor elements are attached to the anode conductive plate and the cathode conductive plate. The anode lead and the cathode lead are respectively connected and housed in a case, and the opening of the case is sealed with four terminals connected to the anode conductive plate and the cathode conductive plate on the inside of the case. An electrolytic capacitor sealed by the body.