JP2008211128A - Metallized film capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve heat dissipation property of a metallized film capacitor used for hybrid cars or the like. <P>SOLUTION: In a metallized film capacitor wherein a metallicon electrode is formed in both edge faces by winding a pair of metallized films, two winding cores 1 formed by winding a metallic foil are disposed in non-contact by providing a clearance 1a coaxially, a pair of metallized films are wound on the two winding cores 1 and each one end of the winding cores 1 is connected to a metallicon electrode 3 each. According to this constitution, the winding core 1 functions as a heat pipe even if an element 2 generates heat and has a high temperature, and the heat is dissipated to an outside through the metallicon electrode 3, thus improving heat dissipation property. Since the winding core 1 is constituted of a metallic foil, mechanical strength is not so high and it is easily subjected to planarization processing, and accordingly unnecessary increase in size is eliminated, and a space efficiency is improved. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a metallized film capacitor which is used in various electronic devices, electrical devices, industrial devices, automobiles, etc., and is particularly suitable for smoothing, filtering, and snubbing of motor drive inverter circuits of hybrid vehicles.

  In recent years, from the viewpoint of environmental protection, all electric devices are controlled by inverter circuits, and energy saving and high efficiency are being promoted. In particular, in the automobile industry, hybrid vehicles (hereinafter referred to as HEVs) that run on electric motors and engines have been introduced into the market, and the development of technologies relating to energy saving and high efficiency has been activated.

  Since such a HEV electric motor has a high operating voltage range of several hundred volts, a metallized film capacitor having high withstand voltage and low loss electric characteristics as a capacitor used in connection with such an electric motor. In addition, the trend of adopting metalized film capacitors having a very long life is also conspicuous due to the demand for maintenance-free in the market.

  FIG. 4 is a partially cutaway perspective view showing the structure of a conventional metalized film capacitor of this type. In FIG. 4, 10 is a metal core, and 11 is a capacitor element layer. 10 is used without being extracted.

  In the conventional metallized film capacitor thus configured, the metal core 10 is excellent in heat dissipation because the heat conduction is good. Since the thermal strength is high, there is little loosening or deformation of the element even when used at relatively high temperatures. Since the mechanical strength is high, it is easy to use a core having a large diameter, and an element having high hardness can be taken up. Since a core with a high dimensional accuracy can be obtained relatively easily, an effect such as being suitable for an element requiring a winding accuracy can be obtained.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
Japanese Patent Laid-Open No. 64-55816

  In the conventional metalized film capacitor, heat is easily trapped in the center of the element by applying a ripple current to the element, and this is dealt with by increasing the heat dissipation by using the metal core 10. However, in recent metallized film capacitors, there is a tendency to increase the capacity and size per element for the purpose of reducing production efficiency and material loss, and the elements are processed flatly in terms of space efficiency. The use of the oval form is increasing.

  Therefore, even if an element that has been enlarged in this way is processed into a flat shape by flattening, the conventional metallized film capacitor is configured to be used as it is without removing the metal core 10. Therefore, the mechanical strength of the metal core 10 is too high, and flat machining is extremely difficult, and the volume of the metal core 10 tends to be bulky, resulting in an increase in size.

  The present invention solves such a conventional problem, and even if the capacity / size per element is increased, the flattening of the element is easy, the size is not increased unnecessarily, and heat is applied to the center of the element. An object of the present invention is to provide a metallized film capacitor which is difficult to be muffled and excellent in heat dissipation.

  In order to solve the above-described problems, the present invention provides an element in which a pair of metallized films in which a metal vapor-deposited electrode is formed on a dielectric film are wound so that the metal vapor-deposited electrode is opposed to the dielectric film. In a metallized film capacitor composed of metallized electrodes formed by metal spraying on both end faces of the element, two cores formed by winding a metal foil are arranged in a non-contact state with a gap on the same axis. The pair of metallized films are wound on the two winding cores, and one end of each of the two winding cores is connected to the metallicon electrode.

  As described above, in the metallized film capacitor according to the present invention, the two cores made of metal foil are arranged coaxially with a gap in a non-contact state, and one end of each of the two cores is connected to the metallicon. Even if the element generates heat and the temperature inside the element rises due to the structure connected to the electrode, the winding core made of the metal foil serves as a heat pipe so that heat can be radiated to the outside through the metallicon electrode. Therefore, the effect of providing a metallized film capacitor having excellent heat dissipation can be obtained.

  In addition, since the core is made of a metal foil, the mechanical strength is not so high, and flattening is easy. Therefore, the metalized film capacitor is excellent in space efficiency without being unnecessarily enlarged. The effect that it can be obtained is also obtained.

(Embodiment 1)
Hereinafter, the first and third aspects of the present invention will be described with reference to the first embodiment.

  1 (a) to 1 (c) are a front sectional view, a side sectional view and a perspective perspective view showing a configuration of a metallized film capacitor according to Embodiment 1 of the present invention, and FIGS. 2 (a) to 2 (c) are the same. FIG. 1 is a front cross-sectional view, a side cross-sectional view, and a perspective perspective view showing a winding state of a metallized film capacitor. In FIGS. 1 and 2, 1 is a core and 2 is an element wound on the core 1. Reference numeral 2a denotes an exterior part of the element 2, and reference numeral 3 denotes a pair of metallicon electrodes formed by metal spraying on both end surfaces of the element 2 including the exterior part 2a to extract electrodes.

  The two cores 1 are configured as a pair, and the two cores 1 are arranged in a non-contact state on the same axis with a predetermined gap 1a (3 mm in this embodiment). Such a winding core 1 is a winding core provided on a winding device (not shown) with an aluminum foil having a thickness of 10 μm (after winding the element, after winding from the winding core of the winding device). This element is formed by winding 10 turns on the element.

  The element 2 is wound on the core 1 with a pair of metallized films in which a metal vapor deposition electrode is formed on a dielectric film (not shown) so that the metal vapor deposition electrodes face each other with the dielectric film interposed therebetween. Thus, the element 2 is formed, and the core 1 is configured to protrude 0.5 mm from each end face of the element 2, and a pair of metallicons is formed on both end faces of the element 2 by metal spraying. The electrode 3 is formed, and this constitutes the metallized film capacitor according to the present embodiment.

  In the metallized film capacitor according to the present embodiment configured as described above, the element 2 generates heat when the element 2 is energized with a ripple current by the configuration in which the metal foil core 1 is connected to the metallicon electrode 3. Even when the temperature inside the element 2 rises, the core 1 made of the metal foil serves as a heat pipe and can radiate heat to the outside through the metallicon electrode 3. It will be able to demonstrate.

  Furthermore, since the metal foil core 1 is not so high in mechanical strength, it is easy to be flattened, and the core 1 is difficult to return to the original shape (circular shape) after the flattening. It is possible to realize a metallized film capacitor that is excellent in space efficiency without being unnecessarily increased in size, as well as being able to improve and stabilize heat dissipation without being generated.

  In the present embodiment, the gap 1a between the two winding cores 1 has been described as 3 mm. However, the gap 1a is preferably as small as possible because it is excellent in heat dissipation efficiency. For reference, it is necessary considering that the insulating distance of the metal deposition pattern formed on the metallized film of the metallized film capacitor having a withstand voltage characteristic of 750 V or 1000 V is set to 1.5 to 2.0 mm. It can be said that the insulation distance is about 2.0 mm.

  Further, the gap 1a between the two cores 1 may be located anywhere in the axial direction, but it is desirable to set it at the center in order to obtain a uniform heat dissipation effect.

  Further, the example in which the core 1 is protruded by 0.5 mm from both end faces of the element 2 has been described. However, the effect of the present invention can be obtained without causing the core 1 to protrude from the end face of the element 2. By projecting, the mechanical joint strength with the metallicon electrode 3 can be improved, whereby the heat dissipation effect can be further improved and stabilized.

(Embodiment 2)
The second aspect of the present invention will be described below with reference to the second embodiment.

  In the present embodiment, the configuration of the winding core of the metallized film capacitor described in the first embodiment with reference to FIGS. 1 and 2 is partially different, and other configurations are the same as in the embodiment. The same reference numerals are given to the same parts and the detailed description thereof is omitted, and only different parts will be described below with reference to the drawings.

  FIG. 3 is a developed perspective view showing the configuration of the core used in the metallized film capacitor according to the second embodiment of the present invention. In FIG. 3, 4 indicates the core, and the core 4 has a thickness of 10 μm. The pair of aluminum foils 5a and 5b are shifted in opposite directions and wound with an insulating spacer 6 interposed therebetween, and the aluminum foils 5a and 5b protrude from both end surfaces, respectively. It is what I did. Moreover, as the insulating spacer 6, a PET film, a PP film, paper, or the like can be used. In the present embodiment, a PP film having a thickness of 3.0 μm is used.

  And the core 4 comprised in this way is a pair of metallized film which formed the metal vapor deposition electrode on the dielectric film which is not illustrated like the said Embodiment 1, and the said metal vapor deposition electrode uses a dielectric film as the said metal vapor deposition electrode. The element is formed by winding on the core 4 so as to face each other, and the aluminum foils 5a and 5b constituting the core 4 protrude from the both end faces of the element by 0.5 mm each. The metallized electrode 3 is formed by metal spraying on both end faces of the element including the aluminum foils 5a and 5b protruding in this way, and the metallized film capacitor according to the present embodiment is configured.

  The metalized film capacitor according to the present embodiment configured as described above has a pair of aluminum foils 5a and 5b with an insulating spacer 6 between them in addition to the effects obtained by the metalized film capacitor according to the first embodiment. Because of the configuration using the core 4 formed by interposing and winding, a slight capacitance is developed between the aluminum foils 5a and 5b of the core 4, and as a result, There is a special effect that the total capacity of the metallized film capacitor can be improved.

  The results of confirming the heat dissipation of the metallized film capacitors of Embodiments 1 and 2 thus obtained were compared with the conventional product (Comparative Example 1 except that it was configured using a PP core). (Table 1).

  In addition, as a test for confirming heat dissipation, it is a self-temperature rise measurement by the ripple current conduction (10 KHz, 20 Arms) to an element.

  As is clear from Table 1, the metallized film capacitor according to the present embodiment has a configuration using a metal foil core, and the heat generated from the element is radiated from the metallicon electrode to the outside through the core. Therefore, it can be seen that it exhibits excellent heat dissipation.

  The metallized film capacitor according to the present invention has an effect of being excellent in heat dissipation, and is particularly useful as an automotive field or the like in which a severe use environment is required.

(A) Front sectional view showing the configuration of the metallized film capacitor according to Embodiment 1 of the present invention, (b) Side sectional view, (c) Perspective perspective view (A) Front sectional view showing winding state of the metallized film capacitor, (b) Side sectional view, (c) Perspective perspective view FIG. 7 is an exploded perspective view showing a configuration of a winding core used in the metallized film capacitor according to the second embodiment of the present invention. Partially cutaway perspective view showing the structure of a conventional metallized film capacitor

Explanation of symbols

1, 4 core 1a gap 2 element 2a exterior 3 metallicon electrode 5a, 5b aluminum foil 6 spacer

Claims (5)

An element in which a pair of metallized films having a metal vapor deposition electrode formed on a dielectric film is wound so that the metal vapor deposition electrode faces through the dielectric film, and both ends of the element are formed by metal spraying. In a metallized film capacitor composed of a metallicon electrode, two winding cores formed by winding a metal foil are arranged coaxially with a gap in a non-contact state, and on the two winding cores A metallized film capacitor in which the pair of metallized films are wound, and one end of each of the two cores is connected to the metallicon electrode. Instead of arranging the two cores formed by winding the metal foil in a non-contact state with a gap on the same axis, the pair of metal foils are displaced in the opposite directions from each other, The metallized film capacitor according to claim 1, wherein a core of a metal foil two-layer structure wound with an insulating spacer interposed therebetween is used. The metallized film capacitor according to claim 1, wherein the core is protruded from the end face of the element. The metallized film capacitor according to claim 1, wherein an aluminum foil or a copper foil is used as the winding core. The metallized film capacitor according to claim 1 or 2, wherein an element having a flat shape is used as the element.

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