JP2009277827A - Capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-reliability capacitor by reducing heat generation, by enhancing the heat dissipation effect of a capacitor element. <P>SOLUTION: The capacitor includes: the capacitor element 14, formed by winding a both-face metallization film, having a metal deposition electrode formed on a dielectric film around a core 11, and providing lead electrodes 13a and 13b on both end surfaces 12a thereof; and an exterior case 15 for housing the capacitor element 14; and an exterior case lid 16. The core 11 is a bottomed cylinder having an opening end at one end and has its external surface insulated, and further, has the opening end fixed to the exterior case lid and its inner surface linked to outside the exterior case to enhance heat dissipation. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a capacitor that is used in various electrical equipment, industrial equipment and the like and has a good heat dissipation effect.

  In film capacitors used in various electrical equipment and industrial equipment, when a large current flows through the capacitor, the capacitor may become hot and exceed the allowable temperature range, and heat dissipation is necessary to prevent such high temperatures. Various studies have been made on capacitors with improved characteristics.

  FIG. 3 is a cross-sectional view of a conventional capacitor having such a heat dissipation effect. The capacitor element 31 is housed inside a case 34 such as polybutylene terephthalate (PBT) resin, and an epoxy resin 35 is provided on the lower side as a filling resin. Is filled, and a heat conductive resin 36 such as heat radiation grease is filled on the upper side.

  As shown in FIG. 4, the capacitor element 31 is formed by winding a metallized film with an insulating film 33 sandwiched between a core 32 and metal spraying the end face to form metallicon electrodes 37 and 38. The upper end portion protrudes upward from the metallicon electrode 37 to form a protruding portion 32a.

  The heat of the capacitor element 31 is transmitted to the thermally conductive resin 36 disposed around the protruding portion 32a, thereby enhancing the heat dissipation effect.

For example, Patent Document 1 is known as prior art document information relating to the invention of the present application.
JP 2006-59890 A

  In the above heat dissipation structure, the heat dissipation effect is influenced by characteristics related to heat dissipation such as the thermal conductivity of the heat conductive resin 36, but the heat conductivity of the heat conductive resin 36 is about 1 to 5 W / (m · K). Therefore, the voltage applied to the capacitor element 31 is higher and the heat generation of the capacitor element 31 is increasing, which is insufficient to be applied to recent electrical equipment and industrial equipment. It was.

  If the heat dissipation is insufficient and the capacitor element 31 is always used continuously at a high temperature, the reliability of the capacitor tends to be reduced.

  In addition, when an abnormal voltage is applied to the electric circuit of an electric device or an industrial device, the temperature of the capacitor element 31 rapidly increases, so that the probability of failure increases. Therefore, more effective heat dissipation is performed. Is required.

  Generally, when the temperature of the capacitor element 31 exceeds 100 ° C., the failure rate increases rapidly, so that it is required to be 90 ° C. or less even if heat is generated.

  Therefore, an object of the present invention is to provide a highly reliable capacitor by further improving the heat dissipation effect from the capacitor element and suppressing heat generation.

  And in order to achieve this object, the capacitor of the present invention is provided with a winding core and a metallized film in which a metal vapor deposition electrode is formed on a dielectric film on the winding core, and provided with extraction electrodes on both end faces. A capacitor having a capacitor element, an outer case for housing the capacitor element, and an outer case lid, wherein the winding core is a bottomed cylinder having an open end at one end, and an outer surface is insulated. The open end of the lead is fixed to the outer case cover, and the inner surface of the core is communicated with the outside of the outer case to improve heat dissipation.

  By connecting the open end of the cylindrical winding core provided on the capacitor element to the outside of the outer case, the heat generated inside the capacitor element is efficiently dissipated through the winding core to the outside air outside the outer case. Can be improved.

  In addition, by fixing the other end opposite to the opening end of the winding core to the bottom surface of the exterior case, heat is efficiently radiated from the bottom surface of the exterior case, and the heat dissipation effect can be further improved.

  Furthermore, by circulating a cooling gas or a coolant such as insulating oil inside the cylinder of the winding core as necessary, the heat generated inside the capacitor element can be radiated more efficiently. There is also an excellent effect that a high capacitor can be provided.

  Hereinafter, a capacitor of the present invention will be described with reference to an embodiment and drawings.

(Embodiment 1)
FIG. 1 is a cross-sectional view showing the internal structure of the capacitor according to the first embodiment. Zinc alloy is vapor-deposited on both sides of a 6 μm polypropylene film (not shown) on a core 11 to form metal-deposited electrodes (not shown). ) And the laminated film 12b on which the metal vapor deposition electrode is not formed are alternately overlapped and wound, and the capacitor element 14 is provided with the extraction electrodes 13a and 13b on both end faces. Is housed in an outer case 15 made of metal such as aluminum.

  The core 11 is a cylinder made of metal such as aluminum or copper whose outer surface is insulated at least. The upper end of the core 11 is an open end 11a. It is fixed so as to protrude from the upper surface.

  The other end side of the winding core 11 is a closed bottom surface 11 b, and this bottom surface 11 b is in contact with the bottom surface 15 a of the exterior case 15.

  The extraction electrodes 13a and 13b of the capacitor element 14 are connected to terminals 18a and 18b provided on the outer case lid 16 by lead wires 17a and 17b, respectively.

  Although the lead wires 17a and 17b are not shown, a necessary portion for ensuring insulation is covered with an insulating sleeve or the like.

  The capacitor element 14 is insulated from the outer case 15 by an insulating case (not shown).

  The interior of the outer case 15 is filled with insulating oil 19 such as polybutene oil, rapeseed oil, or mineral oil to ensure insulation of the capacitor element, and the outer case lid 16 is fixed to the upper surface of the outer case 15 with an anaerobic adhesive. Is sealed.

  At the same time, the vicinity of the open end 11a of the core 11 is also bonded and fixed to the outer case lid 16 with an anaerobic adhesive.

  In the capacitor configured as described above, when a voltage is applied between the terminals 18a and 18b, the capacitor element 14 has a center portion that is close to the core 11 in the left-right direction and a substantially center between the extraction electrodes 13a and 13b in the vertical direction. The position of the part has the highest heat generation temperature.

  The heat transmitted to the core 11 is transported upward and dissipated from the open end 11a in contact with the outside air, and the heat transmitted downward is transmitted from the bottom surface 11b of the core 11 to the exterior case bottom surface 15a and dissipated outside. Will be.

  As described above, the capacitor according to the present embodiment can not only dissipate heat from the bottom surface but also dissipate heat from the upper opening end, so that an efficient heat dissipating effect can be improved.

  Next, a description will be given of the results of trial manufacture of capacitors of the examples and comparative examples in the present embodiment and comparative tests of the heat dissipation effect.

  First, as an example in the present embodiment, the capacitor element 14 is wound on the winding core 11 so that the double-sided metallized film 12a having a thickness of 6 μm and the laminated film 12b on which the metal vapor deposition electrode is not formed are alternated. Prepared and stored in the outer case 15 so that the open end 11a on the upper end side of the core 11 protrudes from the outer case lid 16, filled with polybutene oil, and a capacitor with a rated voltage of 440V and a capacitance of 65μF is manufactured. Sample 1 was obtained.

  Separately from this, as a conventional sample 3 for comparison with the sample 1 of the present embodiment, a capacitor similar to the sample 1 was manufactured except that the winding core 11 was removed after winding.

  For each of these three samples 1 and 3, a voltage 1.25 times (550 V) the rated voltage 440 V was applied at a high temperature of 70 ° C., and the temperature at the center of the capacitor element was measured.

  The results are shown in (Table 1). In Table 1, the temperature rise indicates how much the temperature of the capacitor element rises at an ambient temperature of 70 ° C. The temperature obtained by subtracting 70 from the measured temperature at the center of the capacitor element (° C) It is represented by

  From the results of (Table 1), in the sample 3 of the conventional product, the temperature at the center of the capacitor element was 85.6 ° C. on the average, which was close to the upper limit of the use temperature of 90 ° C. In the sample 1 according to the form, it was kept as low as 83.2 ° C., and there was a margin of about 7 ° C. with respect to the upper limit of the use temperature.

  In general, the failure rate of a capacitor or the like tends to increase exponentially with temperature, and if it can be lowered by several degrees near the upper limit of the operating temperature, the effect is great.

(Embodiment 2)
The difference between the capacitor of the second embodiment and the capacitor of the first embodiment is that the bottom surface 11b of the core 11 is fixed to the holding portion 21 provided on the outer case bottom surface 15a, and is the same as the first embodiment. The same symbols are used for the elements to simplify the description.

  FIG. 2 is an enlarged cross-sectional view of a main part in the vicinity of the outer case bottom surface 15a of the capacitor according to the second embodiment.

  In FIG. 2, the bottom surface 11 b of the winding core 11 is held by a holding portion 21 provided in the exterior case 15.

  The open end 11a of the core 11 is fixed to the outer case lid 16 and the bottom surface 11b is fixed to the holding portion 21 provided in the outer case 15, so that the capacitor element 14 is securely fixed in the outer case 15. In addition, since the bottom surface 11b of the winding core 11 is structured to fit into the holding portion 21, the heat radiation from the outer case bottom surface 15a is more effectively performed.

  Further, although not shown, a coolant such as cooled air, fluorine-based inert liquid (trade name Fluorinert) or low-viscosity insulating oil is put into the inner surface of the core 11 from the open end 11a of the core 11. Thus, more effective heat dissipation can be performed, and a capacitor that can withstand a higher voltage can be obtained.

  As an example in the second embodiment, similarly to the sample 1 of the first embodiment, the double-sided metallized film 12a having a thickness of 6 μm and the laminated film 12b not formed with the metal vapor deposition electrode are alternately wound. The capacitor element 14 is produced by winding on the core 11, and the opening end 11 a on the upper end side of the winding core 11 protrudes from the outer case cover 16 and the other end 11 b (winding) on the opposite side to the opening end 11 a of the winding core 11. The bottom surface of the core 11 is fitted into the holding portion 21 provided in the outer case 15 and stored in the outer case 15, filled with polybutene oil, and a capacitor having a rated voltage of 440 V and an electrostatic capacity of 65 μF is prepared. It was.

  For sample 2, a voltage that is 1.25 times the rated voltage of 440 V (550 V) is applied at a high temperature of 70 ° C. as in the first embodiment, and the temperature at the center of the capacitor element 14 is measured. The results are also shown in 1).

  Further, in Table 2, the results of measuring the temperature by circulating insulating oil (polybutene oil) at room temperature inside the core 11 are also shown in (Table 1).

  As is clear from the results of (Table 1), in sample 2, the temperature at the center of capacitor element 14 is 82.0 ° C., which is 1 ° C. lower than sample 1 according to the first embodiment.

  In Sample 2, the heat transferred to the core 11 is dissipated from the outer case bottom surface 15a via the holding portion 21, so that the heat dissipation effect is further improved.

  In addition, when insulating oil is circulated through the core 11 in the sample 2, the temperature is 79.9 ° C., and the temperature rise is about 2/3 compared to the sample 3 of the conventional product. Furthermore, it has been confirmed that the heat dissipation effect can be enhanced.

  As described in detail above with reference to the first and second embodiments, according to the capacitor of the present invention, the heat dissipation effect from the capacitor element 14 can be improved and the device can withstand a higher voltage due to the extremely simple and easy structure. A highly reliable capacitor can be obtained.

  In the first and second embodiments, the insulating oil 19 is filled in order to prevent the capacitor element 14 from being discharged and to ensure insulation. However, the present invention is not limited to this, and an epoxy resin is used instead of the insulating oil 19. A filling resin such as can also be used.

  As the capacitor element 14, a double-sided metallized film 12 a and a laminated film 12 b that is not metal-deposited are alternately stacked and wound. However, the capacitor element 14 is not limited to this, and is a metal-deposited metal on one side. It may be one obtained by winding at least two fluorinated films.

  Moreover, as a metal vapor deposition electrode, in order to reduce the influence of corona discharge in an alternating current application in this sample, a zinc alloy was used. However, the present invention is not limited to this. Good.

  As the core 11, a plastic resin can be used, but it is preferable to use a metal from the viewpoint of heat conduction.

  Further, when the outer case 15 has a rectangular parallelepiped shape, the capacitor element 14 is pressurized to be flattened to increase the storage efficiency in the outer case 15 and reduce the shape. If 11 is made of metal, it is easy to be deformed into a flat shape. From this point, it is preferable to use a metal core 11.

  The outer case 15 is preferably made of a metal such as aluminum for heat dissipation from the internal capacitor element 14, but may be a resin case.

  Note that when a resin case is used as the outer case 15, the insulating case can be omitted.

  The capacitor of the present invention includes a winding core, a capacitor element in which a metallized film in which a metal vapor deposition electrode is formed on a dielectric film is wound on the winding core, and a take-out electrode is provided on both end faces thereof. A capacitor having an outer case and an outer case lid, wherein the core is a bottomed cylinder having an open end at one end, and an outer surface is insulated, and the open end of the core is the outer case cover The inner surface of the core is connected to the outside of the outer case, and heat inside the capacitor element can be efficiently transferred to the outside, suppressing heat generation of the capacitor element, Since a high capacitor can be provided, it is useful for capacitors used in various electronic devices, industrial devices, and the like.

Sectional drawing which shows the internal structure of the capacitor | condenser in Embodiment 1 of this invention Sectional drawing of the principal part of the capacitor in Embodiment 2 Sectional view showing the internal structure of a conventional capacitor A perspective view for explaining the capacitor element

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Core 11a Open end 11b Bottom surface 12a Double-sided metallized film 12b Laminating film 13a, 13b Extraction electrode 14 Capacitor element 15 Exterior case 15a Exterior case bottom 16 Exterior case lid 17a, 17b Lead wire 18a, 18b Terminal 19 Insulating oil 21 Holding part

Claims (4)

A winding core, a capacitor element in which a metallized film in which a metal vapor-deposited electrode is formed on a dielectric film is wound on the winding core, and an extraction electrode is provided on both end faces of the winding core; an outer case for housing the capacitor element; A capacitor having a case lid, wherein the winding core has a bottomed cylinder having an open end at one end, the outer surface is insulated, and the open end of the winding core is fixed to the exterior case lid and A capacitor characterized in that the inner surface of the winding core communicates with the outside of the outer case. The capacitor according to claim 1, wherein the other end opposite to the opening end of the core is fixed to the bottom surface of the exterior case. The capacitor according to claim 1 or 2, wherein the outer case is filled with insulating oil or filled resin. The capacitor according to claim 1, wherein the inside of the core is cooled by being filled with a liquid or a gas.

Images