JP2014116400A - Capacitor module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology which improves heat radiation performance in a capacitor module where multiple capacitor elements are integrated.SOLUTION: A capacitor module 2 disclosed in the description includes a body 4 and a case 6. In the body 4, multiple capacitor elements 3 are covered by a resin and slits 5 are provided in the resin between the adjacent capacitor elements. Fins 7, each of which fits in the slit 5 when the case is assembled to the body, are provided in the case 6. Heat of the capacitor elements 3 is dissipated to the entire case 6 through the resin of the body and the fins 7. The heat of the capacitor element 3 is dissipated from the case 6 to outer air.

Description

  The present specification relates to a capacitor module in which a plurality of capacitor elements are molded into one with resin.

  When a large-capacity capacitor is required, a plurality of capacitor elements may be connected in parallel and used as one capacitor in terms of circuit. For example, an electric vehicle includes a high-power converter or inverter for driving a driving motor, and a large-capacity capacitor for smoothing current is provided at the input / output terminal of the converter or the input terminal of the inverter. Connected. A capacitor module in which a plurality of capacitor elements are connected in parallel may be used as the smoothing capacitor. In a capacitor module, a plurality of capacitor elements are often covered with resin for insulation. When covering all of a plurality of capacitor elements or a part of each capacitor element with a resin, typically the resin is filled around the plurality of capacitor elements by a processing method such as an injection molding method, and the capacitor elements and the resin are One-piece molding. Patent Documents 1-4 exemplify such capacitor modules. Hereinafter, a resin casing integrally formed with a plurality of capacitor elements may be referred to as a module body.

  Since a large-capacity capacitor generates a large amount of heat, it is important to improve heat dissipation in a capacitor module in which a plurality of capacitor elements are collected. In Patent Documents 1 and 2, slits are provided in the resin between adjacent capacitor elements. Air is passed through the slit to promote heat dissipation from the resin.

JP 2009-044920 A JP 2001-326131 A Japanese Patent No. 4745864 JP 2010-219259 A

  The present specification provides a capacitor module that has better heat dissipation than the conventional one.

  The capacitor module disclosed in this specification includes a module body and a case. Hereinafter, the module body is simply referred to as a “body”. The main body covers a plurality of capacitor elements with resin. The resin is integrally formed with a plurality of capacitors. The main body is provided with a slit in the resin between adjacent capacitor elements. And the fin which fits into a slit is provided in the case which accommodates a main body.

  In the capacitor module having the above structure, fins are inserted into the slits, and the heat of the capacitor element is diffused through the fins throughout the case, thereby improving the heat dissipation efficiency. The finned case is preferably made of a material having high thermal conductivity, and is typically made of copper, aluminum, or the like. The thermal conductivity of copper and aluminum is much larger than that of air, and the thermal conductivity is good.

  Details and further improvements of the technology disclosed in this specification will be described in the following “DETAILED DESCRIPTION”.

It is a perspective view of a capacitor module main body. It is a perspective view of a case. It is sectional drawing in the III-III line arrow of FIG. 4A is a cross-sectional view taken along line IVA-IVA in FIG. 4B is a cross-sectional view taken along the line IVB-IVB in FIG. It is sectional drawing when a case is combined with a main body. It is sectional drawing of the capacitor | condenser module of 2nd Example. (A) is a cross section of the main body, (B) is a cross section of the case, and (C) is a cross section when the case is combined with the main body. It is sectional drawing of the capacitor | condenser module of 3rd Example. (A) is a cross section of the main body, (B) is a cross section of the case, and (C) is a cross section when the case is combined with the main body.

  The capacitor module of the first embodiment will be described with reference to the drawings. FIG. 1 is a perspective view of the main body 4 of the capacitor module 2, and FIG. 2 is a perspective view of the case 6. The case 6 is united with the main body 4 upside down from the direction of FIG. Note that FIG. 1 is represented in a coordinate system with the Z-axis facing up, and FIG. 2 is represented in a coordinate system with the Z-axis facing down. 3 shows a cross section taken along line III-III in FIG. 4A shows a cross section taken along line IVA-IVA in FIG. 1, and FIG. 4B shows a cross section taken along line IVB-IVB in FIG. FIG. 5 is a cross-sectional view when the case 6 is assembled to the main body 4. Note that a bus bar 8 and a terminal 9 to be described later are not shown in FIG.

  The capacitor module 2 of the first embodiment has eight capacitor elements 3. The capacitor element 3 is a film capacitor, for example, and has a cylindrical shape. The eight capacitor elements 3 are covered with resin and constitute one main body 4. The resin of the main body is molded integrally with the capacitor element 3 by an injection molding method. Such a resin molded product is sometimes called a resin mold. As shown in FIG. 1, the eight capacitor elements 3 are arranged in two rows of four capacitor elements. A slit 5 is provided in the resin between adjacent capacitor elements 3.

  As shown in FIG. 2, partition-like fins 7 are provided inside the case 6. The fins 7 are plate-like portions extending from the inner wall of the case 6. When the case 6 is combined with the main body 4, the fin 7 fits into the slit 5 of the main body 4.

  As well shown in FIGS. 3 and 4, a bus bar 8 for electrically connecting the electrode terminals of the eight capacitor elements 3 is embedded in the resin main body 4. The bus bar 8 connects eight capacitor elements 3 in parallel. In addition, a part of the terminal 9 electrically connected to the bus bar 8 inside the resin main body 4 is exposed from the main body 4. The capacitor module 2 can be viewed as a single large-capacity capacitor as a whole, and the two terminals 9 correspond to the electrodes of the capacitor.

  The width of the fin 7 is narrower than the width of the slit 5. As shown in FIG. 5, the heat radiating sheet 12 is disposed in the gap between the fin 7 and the slit 5 when the case 6 is assembled to the main body 4. The fin 7 is in contact with one surface of the heat dissipation sheet 12 and the side surface of the slit 5 is in contact with the other surface. The heat dissipation sheet 12 is a flexible sheet made of, for example, silicon. The heat radiating sheet 12 not only improves the heat transfer from the resin main body 4 to the fins 7 but also functions as a buffer material that protects the capacitor element 3 from vibration. Further, even if the fin 7 expands due to thermal expansion, and the width of the slit 5 narrows, the flexible heat-dissipating sheet 12 contracts between the fin 7 and the side surface of the slit, so that the stress is relaxed between the two. In addition, although illustration is abbreviate | omitted, the thermal radiation sheet is also inserted between the slit 5 of FIG. 3, and the fin corresponding to this.

  The advantages of the capacitor module 2 will be described. The plurality of capacitor elements 3 covered with resin generate heat when a current flows. The heat of the capacitor element 3 is diffused through the resin main body 4 covering the capacitor element 3. A slit 5 is provided in the resin between adjacent capacitor elements 3, and fins 7 are fitted in the slit 5. The case 6 and the fin 7 are made of copper or aluminum and have high thermal conductivity. The heat diffused in the resin main body 4 propagates to the fins 7 through the heat dissipation sheet 12. The heat of the fins 7 diffuses throughout the case 6 and is released from the case 6 to the outside air. The heat of the capacitor element 3 is diffused throughout the case 6 through the fins 7 fitted in the slits 5. Therefore, the capacitor module 2 has high heat dissipation performance.

  The capacitor module 102 of the second embodiment will be described with reference to FIG. 6A is a cross-sectional view of the case 16, FIG. 6B is a cross-sectional view of the main body 14, and FIG. 6C is a cross-sectional view of the capacitor module 102 in which the case 16 and the main body 14 are combined. . In the capacitor module 102 of the second embodiment, the fins 17 are formed in a tapered shape. Further, the slit 15 is also formed in a tapered shape that tapers toward the bottom side in accordance with the shape of the fin 17. As in the capacitor module 2 of the first embodiment, also in the capacitor module 102, when the case 16 is combined with the main body 14, the heat radiation sheet 12 is inserted between the side surface of the slit 15 and the fin 17 (see FIG. 6 (C)).

  The capacitor module 102 of the second embodiment has good workability when the case 16 is combined with the main body 14 because the fins 17 and the slits 15 are tapered. Further, the tapered slit 15 has the advantage that the resin walls on both sides can be thickened near the bottom of the slit, and the strength is high.

  The capacitor module 202 of the third embodiment will be described with reference to FIG. 7A is a cross-sectional view of the case 26, FIG. 7B is a cross-sectional view of the main body 24, and FIG. 7C is a cross-sectional view of the capacitor module 202 in which the case 26 and the main body 24 are combined. . In the capacitor module 202 of the third embodiment, the fin 27 and the slit 25 are formed in a tapered shape, and the height of the fin 27 is not constant. In the capacitor module 202, the three fins 27 are arranged in a line, and the height H1 of the center fin 27a is higher than the height H2 of the end fin 27b. Further, according to the height of the fin, the three slits 25 provided in the example are formed such that the depth L1 of the central slit 25a is deeper than the depth L2 of the end slit 25b. .

  In the capacitor module 202 of the third embodiment, the height H1 of the fins 27a is increased and the depth L1 of the corresponding slits 25a is increased at the center of the main body where the capacitor elements 3 are dense and heat is easily generated. With such a configuration, the contact area between the fin and the side surface of the slit is increased, and the heat transfer efficiency is increased.

  At the end of the line, the height H2 of the fin 27b is set lower than that of the central fin 27a, and the depth L2 of the corresponding slit 25b is set smaller than the depth L1 of the central slit 25a. With such a configuration, the volume of the resin can be increased near the end, and the strength of the main body 24 can be increased.

  Some of the preferred technical features of the technology disclosed herein are summarized below. In the capacitor module disclosed in the present specification, a heat radiation sheet may be disposed between the side surface of the slit and the fin. Heat dissipation sheet increases heat transfer efficiency from resin to fin. The heat dissipation sheet also functions as a buffer material that protects the capacitor element from vibration.

  In the capacitor module disclosed in this specification, it is preferable that the fin is formed in a tapered shape that tapers toward the tip. The tapered fins make it easier to attach the case and improve the assemblability of the capacitor module. Further, the resin of the case and the main body expands as the temperature rises. That is, the fins expand and the slit gap becomes narrower. By making the fin tapered, the stress generated when the fin and the slit come into contact with each other due to thermal expansion can be reduced.

  The capacitor module disclosed in this specification may further include the following configuration. The body is provided with at least three slits side by side. On the other hand, fins corresponding to the three slits are provided side by side in the case. And the height of the fin of the center of a line is made higher than the height of the fin of an end. Furthermore, the depth of the central slit in the line is made deeper than the depth of the slit at the end corresponding to the height of the fin.

  By changing the height of the fin and the depth of the slit as described above, the following advantages can be obtained. Since the capacitor elements are densely packed in the center of the main body, heat is easily generated. By using a fin having a high height in the center, that is, a fin having a large surface area, the heat transport efficiency from the resin main body to the fin can be increased. On the other hand, heat is not generated at the end of the main body as much as the center. On the other hand, the end of the main body is close to a fixing position for fixing the capacitor module to other components. At the end close to the fixed position, the height of the fin is lowered, and the depth of the slit is reduced, thereby ensuring the strength of the main body.

  Points to be noted regarding the technology described in the embodiments will be described. First, the technique disclosed in this specification is not limited to the number of capacitor elements. It is only necessary that two or more capacitor elements are covered with resin, a slit is provided in the resin between the two capacitor elements, and a fin that fits into the slit is provided in the case. The plurality of fins and the plurality of slits need not have the same shape. For example, it is also preferable that the fins and slits at the center of the line are formed in a rectangular shape, and the fins and slits at the end of the line are formed in a taper shape. Moreover, you may change the width | variety of a some fin, and the width | variety of a some slit according to a position.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

2, 102, 202: Capacitor module 3: Capacitor elements 4, 14, 24: Main bodies 5, 15, 25: Slits 6, 16, 26: Cases 7, 17, 27: Fins 8: Bus bar 9: Terminals 12: Heat dissipation sheet

Claims (1)

A plurality of capacitor elements are covered with resin, and a main body in which slits are provided in the resin between adjacent capacitor elements;
A case for housing the main body, provided with a fin that fits into the slit;
A capacitor module comprising:

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