WO2002101771A1

WO2002101771A1 - Film capacitor

Info

Publication number: WO2002101771A1
Application number: PCT/JP2002/005501
Authority: WO
Inventors: Terumitsu Tanaka; Kaneo Miyashita; Kazuo Muroga; Hironobu Kusafuka; Shoji Abo; Takashi Doi
Original assignee: Hitachi Aic Inc.; Toyota Jidosha Kabushiki Kaisha
Priority date: 2001-06-06
Filing date: 2002-06-04
Publication date: 2002-12-19
Also published as: JP2002367857A; JP3597798B2

Abstract

A capacitor element (10) is enclosed by a plus-side external-lead terminal board (11), and a minus-side external-lead terminal board (12) and the plus-side external-lead terminal board (11) are placed one upon another via an insulation film (59). One electrode (21) of the capacitor element (10) is joined to the connection pieces (34, 35) of the plus-side external-lead terminal board (11), and the other electrode (22) to the connection pieces (51, 52) of the minus-side external-lead terminal board (12). The capacitor element (10) is housed into a resin case (13) along with the plus-side and minus-side external-lead terminal boards (11), (12) and they are sealed by an insulation resin.

Description

Description Film capacitor Background of the invention

The present invention relates to a film capacitor, and more particularly, to a film capacitor of an electrode protruding type which is disposed in a resin case by being sealed with a resin, has excellent heat radiation and heat shielding effects, and can reduce self-heating. Related to film capacitors.

As a film capacitor capable of efficiently dissipating heat generated by a capacitor element due to energization, for example, a dry metallized film capacitor disclosed in JP-A-2000-2777377 is known. I have. This film capacitor is formed by winding a pair of metallized films one on top of the other, and connecting in parallel a plurality of capacitor elements, which are formed by spraying metal onto the winding end surfaces to form electrode portions. A heat sink is interposed between each capacitor element to form a capacitor body.The capacitor body is housed in a metal case and sealed with insulating resin.The external lead-out terminal and one end of the heat sink are outside the case. Protruded.

Also, in the dry type high voltage phase-advancing capacitor described in Japanese Utility Model Application Laid-Open No. 5-435333, a metal plate or a material having a high thermal conductivity is placed between the insulating resin potting capacitors arranged in two rows. A heat sink made of an insulating plate is interposed, and a part of the heat sink is placed in contact with the inner surface of the outer metal case so as to be able to conduct heat.

In addition, as described in JP-A-6-106363 and JP-A-11-219854, a heat sink is provided on the connection plate connected to the capacitor element. There is also known an electrolytic capacitor in which the heat dissipation effect is improved by combining the use of the lead terminal connected to the capacitor element and a heat sink. As described above, a radiator plate is conventionally used to efficiently radiate heat generated by a capacitor element. However, most of the conventional capacitors are designed to improve the heat dissipation effect.In order to reduce the self-heating of the capacitor itself and to reduce the external thermal effect on the capacitor element. Took measures Nothing was proposed.

In particular, insulated gate bipolar transistors (hereinafter referred to as IGBTs), which are used as switching elements in recent years, and capacitors used in protection circuits (snapper circuits) for surge voltage during switching of M〇SFET modules. In this case, high frequency, large current and large voltage are required, so it is not enough to enhance the heat dissipation effect.It is necessary to shield the heat from the IGBT and reduce self-heating. ing.

SUMMARY OF THE INVENTION An object of the present invention is to provide a film capacitor that efficiently radiates heat generated by a capacitor element and satisfactorily shuts off heat from the outside to the capacitor element.

Another object of the present invention is to provide a film capacitor in which self-heating is reduced to prevent thermal deterioration and improve life. Summary of the Invention

A film capacitor according to the present invention includes a capacitor element having a pair of electrode parts, first and second external lead-out terminal plates integrally having an internal terminal part and an external terminal part, and an external terminal part protruding outward. And a resin case for resin-sealing the capacitor element and the first and second external lead-out terminal plates in a state in which the capacitor element is included, wherein at least one of the first and second external lead-out terminal plates has a shape including the capacitor element therein. The internal terminal portions of the first and second external lead-out terminal plates are respectively joined to a pair of electrode portions of the capacitor element.

In such a configuration, since at least one of the first and second external lead-out terminal plates surrounds both the peripheral surface of the capacitor element and the electrode portion, the surface area is large, and the heat generation of the capacitor element is efficiently performed. Dissipates heat and also serves as a heat sink. In addition, it has a function as a heat shield in addition to the function as a heat sink. That is, even if heat outside the capacitor is transmitted to the inside through the resin case, at least one of the first and second external lead-out terminal plates including the capacitor element receives the heat and is transferred to the capacitor element. Dissipates heat to the outside without any damage. Therefore, heat from outside is shielded to reduce the thermal effect on the capacitor element. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a plan view of a main part of a snubber circuit of an insulated gate bipolar transistor (IGBT) according to an embodiment of the present invention.

FIG. 2 is a front view of the input-side film capacitor shown in FIG.

FIG. 3 is a cross-sectional view of the input-side film capacitor shown in FIG.

FIG. 4 is an exploded perspective view of the input-side film capacitor shown in FIG. .

FIG. 5 is a front view of the output-side film capacitor shown in FIG.

FIG. 6 is a cross-sectional view of the output-side film capacitor shown in FIG.

FIG. 7 is an exploded perspective view of the output-side film capacitor shown in FIG. Detailed description of the embodiment

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a plan view of a main part of a snubber circuit of an IGBT according to one embodiment of the present invention. As shown in FIG. 1, the opening of the case body 1 that is opened upward is covered with a cover 2, and these constitute a heat sink 3 that houses the IGBT 4. On the inner bottom surface of the case body 1, the input / output film capacitors 5, 6 used for the IGBT 4 and the IGBT 4 snubber circuit are fixed to each other by a plurality of setscrews 7 close to each other. The heat sink 3 is maintained at a required temperature (for example, 65) by water cooling since the IGBT 4 and the input / output film capacitors 5, 6 each constitute a heating element. The input and output film capacitors 5 and 6 are electrically connected to the IGBT 4 via the connection terminals 8 and 9.

Next, the input-side film capacitor 5 will be described in detail with reference to FIGS. As shown in FIG. 4, the input-side film capacitor 5 is composed of a capacitor element 10 and positive and negative external lead-out terminal plates 1 1, 12 1 connected to the respective electrode portions 21, 22 of the capacitor element 10. And a resin case 13 (hereinafter referred to as a resin case) for accommodating the external lead-out terminal plates 11 and 12 and the capacitor element 10, and resin-sealing the capacitor element 10 and the external lead-out terminal plates 11 and 12. And insulating filling resin 14. The capacitor element 10 has a capacitor body 10a formed by laminating two metallized films and winding them a predetermined number of times. The metallized film is composed of, for example, an extremely thin strip-shaped insulating film (polyester film) 17 on which metal electrodes (shaded portions in FIG. 4) 16 are formed by evaporating aluminum or the like on one side. Electrode portions 21 and 22 are formed on both end surfaces in the axial direction of the capacitor main body 10a, so that a so-called deposited electrode type capacitor element 8 is formed. The electrode portions 21 and 22 are formed by spraying a metal or alloy such as copper, zinc, tin, and solder to form a metallikon electrode. The insulating film 17 is wider than the metal electrode 16, and the metal electrode 16 is vapor-deposited along one side edge in the width direction, so that the non-deposited portion (margin portion) 23 on the other side edge is formed. Form. Such an insulating film 17 is overlapped and wound so that the margin portions 23 are alternately left and right opposite to each other, thereby providing electrical connection between the electrode portions 21 and 22 and the metal electrode 16. Enable. In the vicinity of the winding end of the insulating film 17, the metal electrode 16 is removed by a burn-off process and heat-sealed. After the capacitor body 10a is flattened into a desired shape and the electrode portions 21 and 22 are provided, the insulating film 17 is heated to a predetermined temperature (100 to (150 ° C) for a certain period of time (about 3 to 10 hours). In the present embodiment, as shown in FIG. 4, the capacitor element 10 has a length L (dimension in the long axis direction), a width W (dimension in the short axis direction), and a height H (electrode portions 21, 22). Although an example of flattening into an oblong columnar body (dimension between them) was shown, it is a matter of course that a columnar body that is not flattened may be used.

The external lead terminal plate 11 on the plus side is made of a copper plate (C11010H) and has a shape that includes the capacitor element 10 by pressing, that is, around the capacitor element 10 (upper and lower surfaces and Back and part of the front). In order to have both the function as a heat sink and the function as a heat shield, the external lead-out terminal plate 11 is a rectangular plate-shaped internal terminal part 1 slightly larger than the length L and width W of the capacitor element 10. 1A and first and second bent pieces 11B and 11B, which are bent at an angle of about 90 ° so that the upper and lower ends of the internal terminal 11A face each other. The first and second bent pieces 11B and 11C have an angle of about 90 ° after the tip of the first bent piece 11B is once bent in parallel with the internal terminal 11A. External terminal part 1 1D bent in parallel with It is composed of The internal terminal portion 11A and the first and second bent pieces 11B and 11C have a U-shape in side view, and the first bent piece 11B and the external terminal portion 1 1D has a crank shape in side view.

The internal terminal portion 11A has a rectangular opening 33 that is long in the longitudinal direction at the center, and tongue-shaped connecting pieces 34 and 35 face each other at the center of both short side edges of the opening 33. They are extended together. The tips of the connecting pieces 34 and 35 are pressurized so that the plate thickness gradually decreases to reduce the heat capacity, and are joined to one electrode 21 of the capacitor element 10 by welding (or soldering). You. A small rectangular positioning notch 37 is formed at one corner of the lower edge of the internal terminal portion 11A where the first bent piece 11B is continuously provided. The shape for reducing the heat capacity of the connecting pieces 34 and 35 is not limited to the shape in which the thickness is reduced, but may be a shape in which the width is reduced or a shape in which both the width and the thickness are reduced.

The first bent piece 1 1B is formed to be slightly longer than the internal terminal 11A, the right edge 29a thereof is flush with the right edge 28a of the internal terminal 11A, and the left edge 29b. Project laterally from the left edge 28b of the internal terminal 11A. A slit 38 is formed at substantially the center in the longitudinal direction of the first bent piece 11B. The slit 38 is formed in an L-shape so as to extend to the first bent piece 11B and the internal terminal 11A, so that the opening 33 is formed at the tip of the first bent piece 11B. Opened at rim 29c.

The second bent piece 11C has the same length as the internal terminal portion 11A, has the same forward projecting dimension (bending dimension) over the entire length, and is electrically connected to the electrode section 22. The height is set lower than the height H of the electrode portions 21 and 22 in order to prevent the occurrence. At the center in the width direction of the base end portion of the second bent piece 11C, a rectangular opening 41 long in the width direction and the opening 41 are formed at the front edge 30a of the second bent piece 11C. An opening slit 42 is formed. The external terminal portion 11D is composed of two L-shaped terminal portions 31A, 31 extending at predetermined intervals on both sides of the slit 38 following the first bent piece 11B. It consists of B. The lead wire 46 and the plate-like connection terminal 8 are connected to the terminal portions 31A and 3IB, respectively, and a required current (for example, 50A, 10 OKHz) is supplied. The L-shaped terminal portions 31A and 31B are composed of plate portions 31A-1, 31B-1 opposed to the internal terminal portion 11A with the capacitor element 10 interposed therebetween, and plate portions 31Al and 31B-. Than the tip of 1 It is composed of plate portions 31A-2 and 31B-2 bent at substantially right angles. Thus, the external lead-out terminal plate 11 constitutes a two-terminal type terminal plate.

The plate portions 31A-2 and 31B-2 have screw mounting holes 47 into which fixing screws (not shown) for connecting the connection terminals 8 and the lead wires 46 are screwed. On one side of the plate portion 31B-2, a positioning piece 48 is formed by bending downward. The distance between the plate part 3 1 A-1, 3 1 B-1 of the terminal part 3 1 A, 3 1 B and the internal terminal part 11 A is the electrode part 2 2 and the terminal part 3 1 A-1, 3 1 To prevent electrical connection with B-1, the height is set larger than the height H of the capacitor element 10. The inner terminal 11A (excluding the connecting pieces 34, 35), the first and second bent pieces 11B, 11C and the plate 31A-1, 31B-1 Is covered with an insulating film.

The negative-side external lead-out terminal plate 12 is, like the external lead-out terminal plate 11, made of a copper plate (C 110 1 / 4H) and formed into a crank shape in a side view by press working. In order to have both the function as a heat sink and the function as a heat shield plate, the external lead-out terminal plate 12 is bent at a substantially right angle from the rectangular plate-shaped internal terminal portion 12A and the front end of the internal terminal portion 12A. Of the bent piece 12B, and an elongated plate-like external terminal portion 12C bent substantially at a right angle from the upper end of the bent piece 12B. The internal terminal portion 12A has a width that is substantially the same as the length of the first bent piece 11B of the external lead-out terminal plate 11, and is larger than the length. On both sides of the rear end of the internal terminal portion 12A, projections 50 for positioning are protruded. On the front end side of the internal terminal portion 12A, two tongue-shaped connecting pieces 51 and 52 are formed by bending so as to face the rear surface of the first bent piece 12B.

The connection piece 51 is arranged at the middle part of the internal terminal part 12 A, and a rectangular opening 54 for cutting out the connection piece 51 is formed at the middle part in the length direction of the internal terminal part 12 A. The connection piece 52, which is longer than the connection piece 51, is disposed on one side edge of the internal terminal portion 12A, and is provided on one side edge of the internal terminal portion 12A for cutting out the connection piece 52. A rectangular notch 5 5 is formed. Like the connecting pieces 34 and 35 of the external lead-out terminal plate 11, the tips of the connecting pieces 51 and 52 are added so that the thickness gradually decreases toward the tip to reduce the heat capacity. Formed. In this case, needless to say, the width may be reduced, or both the width and the plate thickness may be reduced.

The external terminal section 1 2 C has two screw mounting holes 56 and one positioning bent piece 5 With 7. The screw mounting holes 56 are formed apart from each other in the longitudinal direction of the external terminal portion 12C. The positioning bent piece 57 is formed by bending one side edge of the external terminal portion 12C to the surface side at a substantially right angle.

As shown in FIG. 3, the external lead-out terminal plate 12 configured as described above has an upper surface of the internal terminal portion 12 A and a lower surface of the first bent piece 1 1 B of the external lead-out terminal plate 11. Then, it is assembled to the external lead-out terminal plate 11 in a state of being overlapped so as to be in close contact with a thin insulating film 59. In this state, the connection piece 51 is inserted between the terminal portions 31A and 31B, and the connection piece 52 is located outside the terminal portion 31A. The capacitor element 10 is inserted between the first and second bent pieces 11B and 11C from the side of the external lead-out terminal plate 11 along the internal terminal portion 11A. Thereafter, the connecting pieces 34, 35 of the external lead-out terminal plate 11 are joined to the electrode portion 21 by welding or soldering 61A (FIG. 3), and the external lead-out terminal plate 1 2 is connected to the electrode portion 22. Are connected by welding or solder 61B (FIG. 3).

When the external lead-out terminal plates 11 and 12 are attached to the capacitor element 10, the positioning protrusions 50 of the external lead-out terminal plate 12 are attached to the internal terminals 1 1 of the external lead-out terminal plate 11. Projects backward from A. As shown in Fig. 2, the capacitor element 10 to which the external lead-out terminal plates 11 and 12 are mounted is housed and positioned in the resin case 13 and sealed by filling the insulating resin 14 Is done.

The resin case 13 is made of an epoxy resin or the like, and is formed in a rectangular box shape that is open to the front and large enough to accommodate the capacitor element 10 to which the external lead-out terminal plates 11 and 12 are attached. The resin case 13 is composed of a back plate 13a, a bottom plate 13b, an upper plate 13c, and left and right side plates 13d, 13e, and two side plates 13d, 13 facing each other. A positioning portion 60 for positioning the external lead-out terminal plate 11 protrudes from the body toward the lower side of the inner surface of e. These positioning portions 60 are formed of long ridges in the depth direction of the resin case 13, and a predetermined gap is set between the positioning portion 60 and the bottom plate 13 b. This gap is set to a size that allows the insertion of the second bent piece 11 B of the external lead-out terminal plate 11 and the internal terminal portion 12 A of the external lead-out terminal plate 12.

When assembling the capacitor element 10 into the resin case 13 together with the external lead-out terminal plates 11 and 12, attach the internal terminal 12 A of the external lead-out terminal plate 12 to the inner surface of the bottom plate 13 b. Then, the internal terminal portion 12 A and the first bent piece 11 B of the external lead-out terminal plate 11 are positioned between the bottom plate 13 b and the positioning portion 60. When the capacitor element 10 is housed in the resin case 13 as far as it will go, the tip of the external terminal 11 1 D of the external drawer terminal 1 1 and the external terminal 1 2 C of the external drawer terminal 1 2 Project forward from the opening of the resin case 13. One of the two positioning portions 60 is inserted into the positioning notch 37 of the external lead-out terminal plate 11, and the other is opposite to the notch 37 of the second bent piece 11B. Abuts the upper surface of the side end.

The two positioning projections 50 of the external lead-out terminal plate 12 abut on the corners of the rear plate 13 a of the resin case 13. Therefore, the external lead-out terminal plate 11 is incorporated with the internal terminal portion 11A separated from the rear plate 13a. In this state, the molten insulating resin 14 is filled into the resin case 13 and solidified, so that the capacitor element 10 and the resin case 13 of the external lead-out terminal plates 11 and 12 are housed. Part is completely sealed. Thus, the input side film capacitor 5 is manufactured. As the insulating resin 14, a thermosetting resin such as an epoxy resin or a polyurethane resin is used.

When mounting the input-side film capacitor 5 in the heat sink 3, first, the bottom plate 13 b of the insulating case 13 is placed on a predetermined capacitor mounting portion 1 A on the inner bottom surface of the case 1. Next, as shown in FIG. 1, the positioning bent piece 57 of the external drawer terminal plate 12 is engaged with the positioning hole 64 of the positioning plate 63 formed on the inner bottom surface of the case 1, as shown in FIG. Fix the external terminal 1 2 C to the positioning plate 63 with two setscrews 7. Next, the terminal portion 31 A of the external lead-out terminal plate 11 is connected to the power supply side by a lead wire 46, and the terminal portion 31 B is connected to the IGBT 4 by the connection terminal 8. Next, the details of the output-side film capacitor 6 will be described with reference to FIGS. In FIG. 7, the output-side film capacitor 6 is composed of a capacitor element 70 and positive and negative side external lead-out terminal plates 71, 7 which are respectively joined to the electrode sections 76, 77 of the capacitor element 70. 2, a resin case 73 for housing the external lead terminal plates 71, 72 and the capacitor element 70, and an insulating resin for sealing the capacitor element 70 and the external lead terminal boards 71, 72 7 and 4.

The capacitor element 70 is a capacitor element of the input-side film capacitor 5 described above. A capacitor body 70a formed by winding a metallized film in the same manner as the element 10, and a metal such as copper, zinc, tin, or solder is sprayed on both end faces in the axial direction of the capacitor body 70a. And electrode sections 76 and 77 composed of metallikon electrodes. Such a capacitor element 70 constitutes a vapor deposition electrode type capacitor element. As the capacitor element 70, a flat L-shaped column having a length L0 (dimension in the long axis direction), a width W0 (dimension in the short axis direction), and a height H0 (dimension between the electrode portions 76 and 77) is used. Although an example using a flattened material has been described, it is a matter of course that a cylindrical shape that is not flattened may be used.

The positive-side external lead-out terminal plate 71 is made of a copper plate (C1100 1Z4H) and has a shape substantially enclosing the capacitor element 70 by press processing, that is, a substantially U-shaped front view surrounding the capacitor element 70. It has a shape. In order to serve both as a heat sink and a heat shield plate, the external lead-out terminal plate 71 is provided with a rectangular plate-shaped internal terminal portion 71 A slightly larger than the length L 0 and the width W 0 of the capacitor element 70, and First and second bent pieces 7 IB and 71 C formed by bending both side edges of the terminal portion 71 A downwardly at an angle of approximately 90 ° so as to face each other, and a front end of the internal terminal portion 71 A. And an external terminal 71D extending from the terminal.

The internal terminal 71A is a rectangular plate sufficiently larger than the electrodes 76 and 77, and has an isosceles triangular opening 83 at the center. The top of the opening 83 opens to the front edge of the internal terminal 71A through the slit 83a. A pair of tongue-shaped connecting pieces 84 are formed on the two left and right slopes of the opening 83 so as to face each other. The distal end of the connecting piece 84 is formed under pressure so that the plate thickness gradually decreases in order to reduce the heat capacity. However, the width or both the width and the plate thickness may be reduced. In addition, positioning projections 87 are provided on both sides of the rear end of the internal terminal 71A so as to protrude from the body.

The first and second bent pieces 71B and 71C have the same size and are formed shorter than the height H0 of the capacitor element 70 in order to prevent electrical connection with the electrode portion 77. The external terminal portion 71D includes two terminal portions 81A and 81B extending on both sides of a slit 83a at the front end of the internal terminal portion 71A. Terminal portions 81A and 81B are connected to connection terminals 9 and 85, respectively, to supply a required current (for example, 3 to 5 mm, Ι Ο ΟΚΗζ). As described above, the terminal plate 71 for external drawing has two ends. A sub terminal board is formed. The terminal portions 81A, 81B have first and second bent pieces 71B, 71B at the base end, which have slanted portions 81Al, 81B-1 that are bent obliquely in the direction of C1. . A screw mounting hole into which a fixing screw for connecting the connection terminals 9 and 85 is screwed, and a nut 91 are provided at the distal ends of the terminal portions 81A and 81B. The terminal portion 81B is formed such that a side edge opposite to the terminal portion 81A side protrudes to the side of the third bent piece 71C. Is formed. Note that an insulating film is applied to the inner surface (except for the connection piece 84) of the external lead-out terminal plate 71.

The negative-side external lead-out terminal plate 72 is also made of a copper plate (C1100 1 / 4H), and has a substantially U-shaped front-view shape that is slightly smaller in plan view than the positive-side external lead-out terminal plate 71 by pressing. It has a shape. In order to have both the function as a heat sink and the function as a heat shield plate, the negative side external lead-out terminal plate 72 has a rectangular plate-shaped internal terminal portion 72A, and a substantially upward end at both ends in the longitudinal direction of the internal terminal portion 72A. The first and second bent pieces 72B and 72C bent at a right angle, and the first and second bent pieces 72B and 72C at the front end of the internal terminal portion 72A are bent at substantially right angles in the directions of the first and second bent pieces 72B and 72C. It comprises a third bent piece 72D and an external terminal portion 72E formed by bending the upper end of the third bent piece 72D forward by approximately 90 °.

The internal terminal portion 72A has two tongue-like connecting pieces 95 formed by punching a U-shaped hole 96 near both ends in the longitudinal direction. The distal end of the connection piece 95 is pressurized so that the plate thickness gradually decreases in order to reduce the heat capacity. On both sides of the rear end of the internal terminal portion 72A, positioning projections 98 are integrally provided. The protrusion 98 protrudes rearward from the first and second bent pieces 72B and 72C.

As shown in FIG. 5, the first and second bent pieces 72B and 72C formed to be shorter than the height H0 of the capacitor element 70 in order to prevent electrical contact with the electrode section 76, as shown in FIG. It is inserted between the first and second bent pieces 71B, 71C of the lead-out terminal plate 71, and comes into close contact with the bent pieces 71B, 71C via the thin insulating film 100. A notch 101 for positioning is formed at the base of the front end edge of the second bent piece 72C.

The external terminal section 72E has two screw mounting holes 104 and one positioning bent piece. It has 105. The screw mounting holes 104 are formed apart from each other in the longitudinal direction of the external terminal portion 72E. The positioning bending piece 105 is formed by bending one side edge of the external terminal portion 72E downward substantially at a right angle. One end of the external terminal portion 72E provided with the positioning bending piece 105 protrudes sideward from the first bending piece 72B, and a rear end edge of the protruding end portion is connected to the end portion. A concave portion 107 is formed.

The external lead-out terminal plates 7 1 and 7 2 are fitted from above and below with the capacitor element 70 interposed therebetween, so that the inner terminals 71 A and 72 A of the internal terminal portions 71 A and 72 A of both terminal plates 71 and 72 are fitted. Are in close contact with the respective electrode portions 76, 77 of the capacitor element 70. The connecting pieces 84, 95 are joined to the surfaces of the electrode portions 76, 77 by welding (or soldering) 112a, 112b (Fig. 5). As a result, the external lead-out terminal plates 71 and 72 include the capacitor element 70 in the horizontal direction, and the outer peripheral portions at both ends, which form a semicircular shape in the axial direction of the capacitor element 70, and the electrode portions 76, 7 Cover 7

The resin case 73 is formed in a rectangular box shape whose one side is opened by epoxy resin or the like, and includes a back plate 73 a, a bottom plate 73 b, an upper plate 73 c, and left and right side plates 73 d, 73. e. On the inner surfaces of the bottom plate 73 b and the upper plate 73 c, positioning portions 110 for positioning the external draw-out terminal plates 72, 71 are respectively integrally provided to protrude. The positioning portion 110 is formed by a ridge that is long in the depth direction of the resin case 73. The positioning portion 110 provided on the bottom plate 73 b and the positioning portion 110 provided on the top plate 73 c are slightly opposed to each other. The facing distance is set to a size that allows the external lead-out terminal plates 71 and 72 containing the capacitor element 70 to be fitted with a slight gap. In other words, between the positioning portion 110 of the bottom plate 73b and the positioning portion 110 of the top plate 73c, the external lead-out terminal plates 71, 72 are inserted.

When assembling the capacitor element 70 into the resin case 73 together with the external lead terminal plates 71 and 72, first position the internal terminal portions 71A and 72A of the external lead terminal plates 71 and 72. It is stored along the section 110, and the positioning projections 87, 98 are brought into contact with the respective corners of the back plate 73a. Next, the capacitor element 70 is housed in the resin case 73, and the positioning projections 87, 98 are brought into contact with the back plate 73a. At this time, the positioning recesses 92, 107 of the external drawer terminal plates 71, 72 are at the front ends of the side plates 73 d, 73 e. The ends of the external terminals 71D and the external terminals 72E project from the opening of the resin case 73 forward. At this time, the capacitor element 70 is separated from the back plate 73a. Next, the molten insulating resin 74 is filled in the resin case 73 and solidified, so that the capacitor element 70 and the external drawer terminal plates 71, 72 are housed in the resin case 73. The part is completely sealed with resin. Thus, the output side film capacitor 6 is manufactured. As the insulating resin 74, a thermosetting resin such as an epoxy resin or a polyurethane resin is used.

As shown in Fig. 1 and Fig. 5, the output side film capacitor 6 is mounted in the case 1 by attaching the bottom plate 73b of the resin case 73 to the predetermined capacitor mounting section 1B on the inner bottom surface of the case 1. Place on top. Next, the positioning bent piece 105 of the external lead-out terminal plate 72 is engaged with the positioning hole 121 of the positioning plate 120 provided on the inner bottom surface of the case, and the external terminal portion 72E is inserted. Fix to the positioning plate 120 with two setscrews 7. Next, the terminal portion 81 A of the external lead-out terminal plate 71 and the IGBT 4 are connected by the connection terminal 9, and the terminal portion 81 B is connected to the external terminal 85.

In the input-side film capacitor 5 and the output-side film capacitor 6 configured as described above, heat dissipation and heat shielding can be efficiently performed by the external lead terminal plates on the plus side and the minus side. In addition, heat generation of the capacitor itself can be effectively reduced. Hereinafter, the reason will be described.

In the input-side film capacitor 5, the external lead-out terminal plates 11 and 12 have a large surface area, and the capacitor element 10 is enclosed by the external lead-out terminal plate 11. Therefore, when the capacitor element 10 generates heat due to energization, the heat is transmitted to the external lead-out terminal plates 11 and 12 via the electrode portions 21 and 22 and radiates heat well. In addition, the heat of the external draw-out terminal plates 11 and 12 is transferred from the case body 1 and the cover 2 through the insulating resin 14, the resin case 13 and the positioning plate 63 by heat conduction. And is dissipated. Therefore, it is possible to provide the input-side film capacitor 5 having an excellent heat radiation effect.

In this case, since the first bent piece 1 1B of the external lead-out terminal plate 11 and the internal terminal portion 12A of the external lead-out terminal plate 12 are in close contact with each other via the thin insulating film 59, The heat of the external lead-out terminal plate 11 can be transferred well to the external lead-out terminal plate 12. Furthermore, since the external extraction terminal plate 12 is closer to the case 1 than the external extraction terminal plate 11, heat can be released to the case 1 and the heat radiation effect can be enhanced.

Also, the IGBT 4 itself generates heat or the ambient temperature of the heat sink 3 increases, and the heat is received by the input-side film capacitor 5. In such a case, since the outer periphery of the capacitor element 10 and the electrode portions 21 and 22 are covered by the external lead-out terminal plates 11 and 12, both terminal plates 11 and 12 are externally connected. Block the conduction of heat to the capacitor element 10. That is, even when external heat is transmitted to the inside through the resin case 13, the heat is radiated to the outside without being transmitted to the capacitor element 10 by the external extraction terminal plates 11 and 12. Thus, a thermal effect on the capacitor element 10 can be reduced, and a film capacitor having a high heat shielding effect can be provided.

Also, since the external lead-out terminal plate 11 forms a two-terminal type terminal circuit by the two terminal portions 31 A and 31 B, the opening 33 and the slit 38, both terminal portions 3 The impedance between 1 A and 31 B can be reduced, and the eddy current generated in the internal terminal 11 A due to a change in the magnetic field during energization can be reduced. Furthermore, since the second bent piece 1 1C of the external lead-out terminal plate 11 1 is provided with an open portion 41 opened by the slit 42, the second bent piece 11C is generated. The eddy current generated can be reduced. As a result, it is possible to provide the input side film capacitor 5 which generates less heat from the external lead-out terminal plate 11 itself and generates less self-heating, and is suitable for a film capacitor requiring high frequency, large current and large voltage. It is.

Furthermore, the external drawer terminal plate 12 can be accurately positioned in the resin case 13. That is, since the corner of the resin case 13 has the highest strength, even if distortion occurs during molding, there is little deviation in dimensions. For this reason, the positioning protrusion 50 of the external lead-out terminal plate 12 abuts on the corner of the resin case 13, thereby reducing the error of assembling the external lead-out terminal plate 12 into the resin case 13. it can. As a result, when the resin case 13 is fixed inside the case 1 of the heat sink 3, the bent pieces 5 7 of the external draw-out terminal plate 12 are securely inserted into the positioning holes 6 4 of the positioning plate 6 3. Can be engaged.

On the other hand, in the output side film capacitor 6, the external lead-out terminal plates 7 1 and 7 2 Since the capacitor element 70 has a large surface area and includes the capacitor element 70 in cooperation therewith, when the capacitor element 70 generates heat, the heat can be radiated well. In addition, the heat of the external lead-out terminal plates 71 and 72 is also transmitted to the case 1 by heat conduction through the insulating resin 74, the resin case 73 and the positioning plate 120, and the heat sink 3 Heat is dissipated. Thereby, it is possible to provide the output-side film capacitor 6 having an excellent heat radiation effect.

In this case, the first and second bent pieces 71B, 71C of the external lead-out terminal plate 71 and the first and second bent pieces 72b, 71 of the external lead-out terminal plate 72 are provided. Since 2 C is closely in contact with the thin insulating film 100 via the thin insulating film 100, the heat of the external extraction terminal plate 71 can be satisfactorily released to the external extraction terminal plate 72. Further, since the external lead-out terminal plate 72 is closer to the case 1 than the external lead-out terminal plate 71, heat can be released to the case 1 and the heat radiation effect can be enhanced.

Also, when the IGBT 4 itself generates heat or the ambient temperature of the heat sink 3 becomes high and the output-side film capacitor 6 receives the heat, the external draw-out terminal plates 7 1 and 7 2 remove the heat from the outside to the capacitor. Since the transmission to the element 70 is blocked, the thermal effect on the capacitor element 70 can be reduced. This makes it possible to provide a film capacitor 6 having a heat shielding effect against external heat.

In addition, since the opening 83 opened by the slit 83a is provided in the internal terminal 71A of the external lead-out internal terminal 71, the terminal plate has a two-terminal structure. The impedance between A and 81B can be reduced, and the heat generation of the terminal plate 71 itself can be reduced. Furthermore, an eddy current generated in the internal terminal portion 71 A due to a change in the magnetic field is small, and a capacitor with less self-heating can be provided.

Further, the external drawer terminal plates 71 and 72 can be accurately positioned in the resin case 73. That is, since the corners of the resin case 73 have the highest strength, even if distortion occurs during molding, there is little deviation in dimensions. Therefore, the positioning protrusions 8 7, 9 8 of the external lead-out terminal plates 7 1, 7 2 come into contact with the corners of the resin case 7 3, and the resin of the external draw-out terminal plates 7 1, 7 2 Case 7 Incorporation error in 3 Can be reduced. As a result, when the resin case 73 is fixed in the case 1 of the heat sink 3, the positioning bent pieces 105 of the external lead-out terminal plate 72 are aligned with the positioning holes 1 of the positioning plate 120. It can be surely engaged in 2 1.

It should be noted that the present invention is not limited to the above-described embodiment at all, and various changes and modifications can be made without departing from the gist of the invention. For example, in place of the IGBT 4, a known switching element such as M〇S_FET may be employed. レ In the input-side film capacitor 5, both ends of the capacitor element 10 in the major axis direction may be used. A bent piece that covers the outer peripheral portion may be formed by bending both end portions of the internal terminal portion 12 A of the external lead-out terminal plate 12. In the output-side film capacitor 6, the internal terminal portion 71A of the external lead-out terminal plate 71 or the internal terminal portion 72A of the external lead-out terminal plate 72 is provided at the rear end of the capacitor element 70. A bent piece covering the outer peripheral surface may be provided.

In the above-described embodiment, an example is shown in which the resin cases 13 and 73 of the film capacitors 5 and 6 on the input side and the output side are fixed laterally to the inner bottom surface of the case 1 constituting the heat sink 3. However, the present invention is not limited to this. For example, in the case of a vertical plate-shaped heat sink, the heat sink may be fixed to the vertical surface. As described above, according to the present invention, the heat radiation and heat shielding effects are excellent, and the heat generated by the capacitor itself can be reduced, so that the thermal deterioration of the capacitor can be improved and the life can be extended. it can. In particular, it is suitable for capacitors used in circuits requiring high frequency, large current and large voltage. In addition, since the terminal plate has both the function as a heat sink and the function as a heat shield, there is no need to provide a separate heat sink and heat shield, and the number of components can be reduced.

Further, according to the present invention, by forming a two-terminal type terminal plate by forming an opening and a slit in the positive-side external lead-out terminal plate, the impedance between the two terminal portions is reduced, and eddy current is generated. And the heat generation of the terminal board for external lead on the positive side can be further reduced.

Further, according to the present invention, since the plus side external drawing terminal plate and the minus side external drawing terminal plate are provided with plate portions which are close to each other and opposed to each other and in close contact with each other via an insulating member, It has good heat conduction and can further improve the heat dissipation effect. Further, according to the present invention, it is possible to accurately position the external lead-out terminal plate by the inner corner portion of the resin case, and to reduce an error in assembling the terminal plate into the resin case.

Furthermore, according to the present invention, when the connection piece of the external lead-out terminal plate and the electrode portion of the capacitor element are joined by welding or soldering, heat conduction from the connection piece to the electrode portion is small because the heat capacity of the connection piece is small. The bonding speed is fast and the bonding can be done quickly, and the temperature drops quickly after bonding, so that the thermal effect on the capacitor element can be reduced.

Claims

The scope of the claims

1. A capacitor element having a pair of electrode parts, first and second external lead-out terminal plates integrally having an internal terminal part and an external terminal part, and the external terminal part being protruded outward. A film capacitor comprising: a capacitor element; and a resin case for resin-sealing the first and second external lead-out terminal plates,

At least one of the first and second external lead-out terminal plates is formed in a shape including the capacitor element, and each of the internal terminal portions of the first and second external lead-out terminal plates is formed of the capacitor element. A film capacitor characterized by being joined to a pair of electrodes.

2. An opening formed at the center of the internal terminal portion of the first external lead-out terminal plate and opening to an edge of the first external lead-out terminal plate through a slit; and an opening of the opening portion. A tongue-shaped connecting piece integrally extended to the edge and joined to the one electrode portion,

The internal terminal portion of the first external lead-out terminal plate has a shape covering a surface of one electrode portion of the capacitor element, and the external terminal portion of the first external lead-out terminal plate is formed of the slit. 2. The film capacitor according to claim 1, wherein the film capacitor extends integrally on both sides.

3. The film capacitor according to claim 1, wherein each of the first and second external lead-out terminal plates has a pair of plate portions in which opposing surfaces contact each other via an insulating member.

4. It further comprises a heat sink disposed outside the resin case, wherein at least one of the internal terminal portions of the first and second external lead-out terminal plates is disposed close to the heat sink. The film capacitor according to claim 3, wherein

5. The resin case, wherein the resin case is fixed to the heat sink such that at least a part of the first and second external lead-out terminal plates is close to the heat sink. Film capacitor.

6. At least one of the first and second external lead-out terminal plates is integrally provided at both ends of the rear end edge thereof with projections for positioning and abutting on inner corners of the resin case. 2. The film capacitor according to claim 1, wherein:

7. The film capacitor according to claim 2, wherein the connection piece of the first external lead-out terminal plate has a shape having a small heat capacity.

8. Further provided is a plate portion extending to the internal terminal portion of the first external lead-out terminal plate and covering one side surface of the capacitor element, wherein the plate portion is opened to an edge through a slit. 2. The film capacitor according to claim 1, comprising: