JPH0241858Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a capacitor in which a single capacitor element containing a plurality of small-capacity unit capacitors is coated with a resin, and is prevented from being damaged due to partial destruction of the element. Generally, a single capacitor element containing multiple single capacitors of small capacity has a laminated structure in which multiple metalized films are laminated, or a pair of metalized films in which margin portions are provided intermittently in the length direction. A layered and wound structure has been proposed. However, in a capacitor with such an element configuration, even if dielectric breakdown occurs in a part of the metallized film during use, the broken part will not occur because the metallized film part is partially independent. It is attracting attention because it does not spread to the metallized film and does not lose its capacitor function. Conventionally, for a capacitor having such an element configuration, as shown in FIG. It is attached, then stored in a resin case 4, and the gap is filled with sealing resin 5. However, in the capacitor configured as described above, even if the metallized film constituting the capacitor element 1 were to be destroyed for some reason, the evaporation portion would not be continuous, so the destruction would be limited to only a local portion. Although the function as a capacitor can be maintained, capacitor element 1
Since the whole is tightly covered with sealing resin 5,
There is a risk that the resin case may crack due to the gas pressure generated at the time of local failure, and the safety function cannot be fully fulfilled. This invention was made in view of the above points,
In a capacitor consisting of a single capacitor element containing a plurality of small-capacity single capacitors and encased in a resin case, local parts of the capacitor element can be The object of the present invention is to provide a capacitor that absorbs the gas pressure generated during mechanical breakdown and eliminates the risk of damage to the exterior. The present invention will be explained below with reference to examples. That is, as shown in FIG. 2, for example, a margin part 11 is provided on one end surface in the width direction, and cuts 12 are provided intermittently in the length direction continuous with the margin part 11, thereby dividing the vapor deposition electrode 13 into a pair. Using the metallized film 14, the margin portions 11 are stacked and wound in opposite directions, as shown in FIGS. 3 and 4.
As shown in the figure, metallicon electrodes 16 are formed on both end surfaces of a capacitor element 15 containing a plurality of small-capacity single capacitors. Next, after attaching the lead terminal 17 to the metallicon electrode 16, a sponge-like insulating material 18 made of, for example, a sheet of foamed polyethylene and having a porosity of 60 to 90% and having a pressure absorbing effect is applied to all sides of the capacitor element 15. Wrap it around, store it in the resin case 19,
After that, the resin case 19 has a viscosity of 20 to 500 cp.
It is filled with a sealing resin 20 of. In this case, the porosity of the sponge-like insulating material 18 and the viscosity of the sealing resin 20 to be filled are set according to the sealing resin 2.
The relationship shall be examined in such a way that zero does not penetrate into the sponge-like insulating material 18 and the porosity of the sponge-like insulating material 18 can be maintained. For example, if the porosity is large, use a material with as high a viscosity as possible,
If the porosity is small, use a material with low viscosity; in any case, the sealing resin 20 is the sponge-like insulating material 1.
8 shall be avoided. In the capacitor configured as described above, if a part of the vapor deposited electrode 13 of the metallized film 14 constituting the capacitor element 15 is broken, the breakage will not spread to other parts of the vapor deposited electrode 13 due to the cuts 12. However, although internal pressure is generated due to gas generation, the sponge-like insulating material 18 arranged to prevent the sealing resin 20 from penetrating absorbs the gas pressure, so the internal pressure is alleviated and the resin case 19
It is possible to prevent cracking and completely eliminate the risk of damaging other attached equipment, and although the capacitance is slightly reduced due to the broken part, it still has the excellent effect of operating without losing its function as a capacitor. There is. In the above embodiment, a sheet of foamed polyethylene was wound around all sides of the element as a sponge-like insulating material. However, as shown in FIG. A similar effect can be obtained with a structure in which foamed polyethylene is provided as the sponge-like insulating material 23 on the surface. In Fig. 5, 24 is a pull-out terminal, 25
2 is a resin case, and 26 is a sealing resin. Next, based on the experimental results, the case failure situations of the present invention and the conventional example will be explained. That is, a 200VAC-1μF capacitor element is made by winding a metallized polypropylene film with a thickness of 5μ and vapor-deposited electrodes divided into 20mm width pieces using a known method, and a foamed polyethylene sheet with a thickness of 1mm is wrapped around all sides of the capacitor element. This invention A consists of the structure shown in FIGS. 3 and 4 in which the capacitor element is wrapped around the capacitor element, and the invention B consists of the structure shown in FIG. Conventional example C consisting of the configuration shown is placed in a constant temperature oven at 70℃.
The results of investigating case cracking after 1000 hours after applying 400 VAC were as shown in the table below. The samples were 20 each of A, B, and C.

[Table] As is clear from the table above, conventional example C has 15 out of 20
On the other hand, the case may crack and the safety function of the capacitor element structure cannot be fully utilized.
Both inventions A and B had no case cracking defects, and exhibited an excellent effect of making full use of the safety function of the capacitor element structure. From this result, it can be seen that conventional example C has a case failure that can absorb the internal pressure due to gas generation caused by partial destruction of the metallized film caused by the application of double voltage, whereas present inventions A and B have case failure that can absorb the internal pressure. This is thought to be based on the result that the sponge-like insulating material absorbs the In addition, in the above embodiment, a configuration using the sponge-like insulating material itself was explained, but the surface of the part of the sponge-like insulating material that is placed in a part other than the part that is in close contact with the capacitor element part is thermally welded to remove that part. The seepage of the sealing resin can be completely prevented by smoothing it or by laminating a plastic film 28 on the parts of the sponge-like insulating material 27 other than those in close contact with the capacitor element as shown in FIG. , on the other hand, is valid. Further, in the above embodiments, a wound type capacitor element structure has been exemplified and explained, but it goes without saying that the present invention can also be applied to a laminated type capacitor element structure. As described above, according to the present invention, in a capacitor formed by resin molding a single capacitor element containing a plurality of small-capacity single capacitors,
By closely adhering the sponge-like insulating material to the side surface and/or end surface of the capacitor element, a capacitor without the risk of damage to the exterior can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional capacitor, FIG. 2 is a plan view showing a metallized film constituting a capacitor element according to an embodiment of the present invention, and FIGS. 3 and 4 are an embodiment of the present invention. 3 is a front sectional view, FIG. 4 is a side sectional view, FIG. 5 is a sectional view of a capacitor according to another embodiment of the present invention, and FIG. 6 is a further embodiment of the present invention. FIG. 2 is a cross-sectional view showing a sponge-like insulating material constituting a capacitor according to an embodiment of the present invention. 15, 21... Capacitor element, 16, 22...
...metallicon layer, 18,23,27...sponge-like insulating material, 19,25...resin case, 20,2
6...Sealing resin, 28...Plastic film.

Claims (1)

[Claims for Utility Model Registration] (1) A single capacitor element containing a plurality of small-capacity unit capacitors with metallized layers formed on both end faces, and a sponge-like insulating material closely attached to the sides and/or end faces of the capacitor element. A capacitor comprising: a resin case housing the capacitor element with the insulating material in close contact with the capacitor; and a sealing resin filled in the resin case. (2) The capacitor according to claim (1) of the utility model registration, characterized in that the sponge-like insulating material is foamed polyethylene or foamed polyurethane. (3) The capacitor according to claim (1) or (2) of the utility model registration claim, characterized in that the surface portion of the sponge-like insulating material that does not come into close contact with the capacitor element is welded. (4) Scope of Utility Model Registration Claim No. 1 characterized in that a plastic film is laminated on the surface portion of the sponge-like insulating material that does not come into close contact with the capacitor element.
The capacitor according to any one of (1) to (3).