Electrical power conversion device

Abstract

An electrical power conversion device (1) comprising: an electrical power semiconductor device (14); an electrode wiring element (13) connected to a main electrode of the electrical power semiconductor device (14); a housing (30); a fuse section (16) formed in the electrode wiring element (13) and acting as a fuse; a fuse resin element (26) arranged between the fuse section (16) and the housing (30);and a sealing resin element (25), which is a resin element for sealing the electrical power semiconductor device (14), the electrode wiring element (13), the fuse section (16) and the fuse resin element (26) in the housing (30), wherein the fuse section (16) is formed from a section of the electrode wiring element (13) having a cross-sectional area smaller than that of each of the sections at the upstream and downstream positions of the same in the direction of current flow.

Description

TECHNICAL FIELDThe present invention relates to an electric power conversion device in which a resin member seals an electric power semiconductor device in a case.PRIOR ARTIn recent years, vehicles such as a hybrid car and an electric car, each using an engine as a drive source, have been actively developed in the automobile industry. An inverter for driving the motor uses a battery as a power source to supply the motor with a high driving electric power. Moreover, in the inverter, a resin sealing type electric power semiconductor device is used; therefore, in the field of power electronics, the importance of an electric power conversion device as a key device is increasing.The electric power semiconductor device used in the inverter and other components are integrally sealed with resin. In such an electric power converter, when a short-circuit fault occurs in an electronic component such as an electric power semiconductor device or a smoothing capacitor in a snubber circuit during supply of electric power from the battery, an excessive short-circuit current flows. For example, when the upper and lower arms of the inverter are short-circuited due to a malfunction of a gate drive circuit in an inverter control circuit, an excessive current flows in the power semiconductor device and a short-circuit fault occurs.In the short-circuit state, the connection of a relay for connecting the battery to a motor drive circuit or continuation of the connection causes a large current to cause the electric power conversion device to emit smoke and burn out. Moreover, it is conceivable that the battery connected to the motor-driven inverter is damaged by the flow of an excessive current exceeding the rated power. In order to prevent these situations, a sensor for detecting an excessive current is generally used, so that when the current flow is excessive, the current is cut off by controlling the switching of the electric power semiconductor device at high speed. However, it is desired that even if the electric power semiconductor device fails due to a short circuit, the aforementioned failure modes such as smoke generation and the like are more securely prevented.In particular, for example, when an excessive current cut-off fuse is inserted into the electric power semiconductor device and the battery, the excessive current flowing between the motor-driven inverter and the battery can be prevented.However, a chip-type excessive current shutdown fuse is expensive. Therefore, an excessive current cut-off means is required which is inexpensive but can securely cut off an excessive current which might flow due to a short circuit in the event of failure of the electric power semiconductor device. For example, in the above-mentioned PLT 1, an external terminal electrode protruding outward from a semiconductor device is cut to reduce the cross-sectional area thereof, so that a fuse portion is formed.PTL 2 describes a semiconductor device including semiconductor elements and at least one fuse sealed by resin or otherwise in an airtight manner.CITI ANIMAL LISTPatent LiteraturePTL 1: JP 2005-175439 APTL 2: DE 38 89 563 T2SUMMARY OF THE INVENTIONTechnical ProblemHowever, in the technology in PLT 1, the fuse portion provided in the external terminal electrode is exposed to the outside of the semiconductor device. Accordingly, when the fuse portion is melted by an excessive current, smoke may flow out from the device; moreover, sparks may be scattered to the outside, so that a combustion reaction utilizing the outside air may lead to burning out of the device. Moreover, the material of the fused fuse portion may be scattered to the atmosphere, so that the external terminal electrode and a peripheral element may be short-circuited. Since the thermal conductivity of gas is low, the heat generated in the fuse portion is not radiated to the outside air but is transferred to the semiconductor device, thereby damaging the semiconductor device.Accordingly, an electric power conversion device is desired in which smoke generation, burning out, and short circuit between the fuse portion and a peripheral member caused by a molten material can be suppressed even when the fuse portion is melted by an excessive current.Solution of the ProblemThis object is achieved by the electric power conversion device according to claim 1.Advantage of the InventionIn a power conversion device according to the present invention, a fuse portion is formed in an electrode wiring member; since an expensive chip fuse is not provided, the cost for the fuse portion can be reduced. Since a sealing resin member covers the fuse portion and a fuse resin member, the material of the fused fuse portion is prevented from being scattered outward. In addition, since the fuse portion and the fuse resin member can be shut off from the outside air, arc discharge generated during the fusing operation can be prevented from causing combustion reaction and smoke generated during the fusing operation can be prevented from escaping to the outside. The arrangement of the fuse resin member between the fuse portion and the housing enables the melted material of the fuse portion to be prevented from coming into contact with the housing and a short circuit between the electrode wiring member and the housing to be suppressed. Moreover, since it is possible that the heat generated in the fuse portion during the melting process is transferred to the case via the fuse resin member, and thus the fuse portion is cooled, the generated heat can be suppressed so that the electric power semiconductor device, the sealing resin member, and the like are not damaged. In addition, since the fuse resin member dedicated to the fuse portion is provided, a resin member can be selected from a material suitable for melting the fuse portion; thereby, the insulation performance and the cooling performance at the time of melting can be increased. Thereby, the insulation performance and the cooling performance during melting can be increased. Thereby, smoke generation, burning-through, and short circuit between the fuse portion and a peripheral member caused by a molten material can be suppressed even when the fuse portion is melted by an excessive current.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a plan view of an electric power conversion device according to Embodiment 1 of the present invention; FIG. 2 is a cross-sectional view of the electric power conversion device according to Embodiment 1 of the present invention when taken at the cross-sectional position B-B in FIG. 1 ; FIG. 3 is a cross-sectional view of the electric power conversion apparatus according to Embodiment 1 of the present invention taken at the cross-sectional position A-A in FIG. 1. FIG. 4 is a schematic diagram for explaining a current density in a fuse section according to Embodiment 1 of the present invention; FIG. 5 is a set of schematic views for explaining the variation of the shape of the fuse portion according to Embodiment 1 of the present invention; FIG. 6 is a set of schematic views for explaining the variation in the shape of the fuse portion according to Embodiment 1 of the present invention; FIG. 7 is a cross-sectional view of an electric power conversion device according to Embodiment 2 of the present invention when taken at the A-A cross-sectional position in FIG. 1 ; and FIG. 8 is a cross-sectional view of an electric power conversion device according to Embodiment 3 of the present invention when taken at the A-A cross-sectional position in FIG. 1.DESCRIPTION OF THE EMBODIMENTSEmbodiment 1An electric power conversion device 1 according to Embodiment 1 will be explained with reference to drawings. FIG. 1 is a plan view of the electric power conversion apparatus 1 as viewed from the opening side of a housing 30; in order to explain the arrangement of the respective components, a sealing resin member 25 is made transparent and not illustrated. FIG. 2 is a cross-sectional view taken at the cross-sectional position B-B in FIG. 1; FIG. 3 is a cross-sectional view taken at the cross-sectional position A-A in FIG. 1. Since each of FIGS. 1, 2, and 3 is a schematic diagram, the respective dimensions of the individual elements in the drawings do not completely coincide.The electric power conversion device 1 includes an electric power semiconductor device 14, an electrode wiring member 13 connected to the main electrode of the electric power semiconductor device 14, the case 30, and the sealing resin member 25 that is a resin member that seals the respective components such as the electric power semiconductor device 14 and the like in the case 30.< Housing 30>The housing 30 is in the form of a bottomed tube, and serves as a frame for molding the sealing resin member 25 into a mold. It is assumed that in the case where "inside" and "inside" or "outside" and "outside" are simply referred to below, the inside or outside of the housing 30 is respectively referred to below. It is assumed that "longitudinal direction" means the direction in which the tubular portion of the housing 30 is elongated, and "transverse direction" means the direction in which the lower portion of the housing 30 is elongated.The lower portion of the case 30 is made of a metallic heat sink 12. the heat sink 12 functions to radiate the heat generated in the electric power semiconductor device 14 to the outside. For the heat sink 12, for example, a material such as aluminum, an aluminum alloy, or the like having a thermal conductivity of 20 W / (mK) or higher is used. The heat sink 12 is formed in the shape of a rectangular flat plate. A device-facing protruding portion 12 athat protrudes inward and has a flat plate shape is provided in the inner surface portion of the heat sink 12 facing elements on the power semiconductor electric device 14 side; the inner surface of the device-facing protruding portion 12 aabuts the elements on the power semiconductor electric device 14 side. As illustrated in FIG. 2, two or more flat plate fins 19 spaced apart from each other are provided on the outer surface of the heat sink 12. The fin 19 is in contact with the outside air; the heat sink 12 radiates heat from the fin 19 toward the outside air. A water cooling type may be allowed to be used.The tubular portion of the housing 30 is made of an insulating housing 11, and the insulating housing 11 is formed by using any resin material having high insulating ability and high thermoplasticity, for example, polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), or the like.<The Electric Power Semiconductor Device 14, the Electrode Wiring Member 13>In the present embodiment, the electric power semiconductor device 14 and the electrode lead frames 13 as electrode wiring members 13 are sealed with a device molding resin 20 which is a resin member; as a result, a packaged semiconductor device module 29 is obtained. A control lead frame 21 connected to a control terminal of the electric power semiconductor device 14 is also sealed with the device molding resin 20. The electrode lead frames 13 and the control lead frame 21 protrude outward from the device molding resin 20. It is desirable that a hard resin having a modulus of elasticity of several GPa is used as the device molding resin 20 so that the internal device and the wirings are protected; for example, an epoxy resin is used.As the electric power semiconductor device 14, a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is used. It is allowed that, as the electric power semiconductor device 14, another type of switching device such as an insulated gate bipolar transistor (IGBT) to which a diode is connected in antiparallel is used. The electric power semiconductor device 14 is a device used in an inverter circuit or an inverter circuit for driving a device such as a vehicle drive motor, and controls a rated current of several amperes to several hundred amperes. As a material for the electric power semiconductor device 14, silicon (Si), silicon carbide (SiC), gallium nitride (GaN), or the like can be used.The electric power semiconductor device 14 is formed in the shape of a rectangular flat plate chip; the drain terminal as a main electrode is provided in the surface thereof on the heat sink 12 side, and the source terminal as a main electrode is provided in the surface thereof on the side opposite to the heat sink 12 side of the case 30. In addition, the gate terminal as a control terminal is provided in its surface on the side opposite to the heat sink 12 side of the package 30. It may be allowed that as the control terminal, a sensor terminal or the like for detecting a current flowing between the main electrodes is provided.The drain terminal is connected to an electrode lead frame 13a having positive polarity; the source terminal is connected to an electrode lead frame 13b having negative polarity via an electrode wiring member 15a. Since a large current flows therethrough, the electrode wiring member 15 ais formed of, for example, an element obtained by processing a plate material of gold, silver, copper, or aluminum; alternatively, the electrode wiring member 15 ais formed by wire bonding or tape bonding. Both the gate terminal and the sensor terminal are connected to the control lead frame 21 via a control wiring member 15 b. The control wiring member 15 bmay be formed by, for example, wire bonding with gold, copper, aluminum, or the like, or by tape bonding with aluminum.Both the positive polarity electrode lead frame 13 aand the negative polarity electrode lead frame 13 bare formed in a flat plate shape. The respective electrode terminal portions of the electrode lead frames 13 aand 13 bconnected to the main electrodes of the electric power semiconductor device 14 are disposed on the side closer to the heat sink 12 than to the electric power semiconductor device 14. The surface of the electrode connection portion of the electrode lead frame 13 awith positive polarity on the side opposite to the heat sink 12 side is bonded to the drain terminal on the surface of the power semiconductor electric device 14 on the heat sink 12 side with a conductive bonding material 17. The surface of the electrode connection portion of the electrode lead frame 13 bhaving negative polarity on the side opposite to the heat sink 12 side is bonded to one end of the electrode wiring member 15 awhich is formed in an L shape with the conductive bonding material 17. The source terminal on the surface of the electric power semiconductor device 14 on the side opposite to the heat sink 12 side is bonded to the other end of the electrode wiring member 15 awith the conductive bonding material 17. The conductive bonding material 17 is made of, for example, a highly conductive and thermally highly conductive material such as solder, silver paste, a conductive adhesive, or the like.The surface on the heat sink 12 side of the electrode terminal portion of each of the electrode lead frames 13 aand 13 bis not covered with the device molding resin 20 but exposed to the outside of the semiconductor device module 29. Each of the exposed portions of the electrode lead frames 13 aand 13 bis in contact with the inner surface of the device-facing protruding portion 12 aof the heat sink 12 via the insulating member 18 shaped in a plate shape. The insulating member 18 is formed of a material having high thermal conductivity and high electrical insulating property. For example, the insulating member 18 is made of grease, an insulating film, or an adhesive made of a resin material such as a silicone, epoxy, or urethane resin, which has an insulating property and a thermal conductivity of several W / (mK) to several tens of W / (mK). Moreover, the insulating member 18 can be formed by the combination of a resin material with another material such as a ceramic or metal substrate having high heat resistance and high insulating property.In order to limit the thickness of the insulating member 18, a protrusion 20 ais provided on the heat sink 12 side in the mold resin device 20. By pressing the protrusion 20 aof the device mold resin 20 against the heat sink 12, the thickness of the insulating member 18 can be limited by the height of the protrusion 20 a; thereby, the insulating property and the heat conductive property of the insulating member 18 can be controlled. For example, in the case of a low-pressure automobile having a 12-volt battery, the creepage distance required to secure a predetermined withstand voltage is substantially 10 μm. Accordingly, in the case of a low-pressure automobile, the thickness required for insulation can be reduced; thereby, the protrusion 20 aof the device molding resin 20 can be shortened, and thus the thickness of the electric power conversion device 1 can be reduced. In the case where the insulating member 18 is made of a material having high rigidity and the thickness of which is little changed by the pressing force, the thickness of the insulating member 18 can be controlled; thus, the protrusion 20 aof the device molding resin 20 is not required.The gap between the heat sink 12 and the electrode lead frames 13 aand 13 bsealed with the device molding resin 20 can be controlled by the protrusions 20 a, and therefore, the thickness of a fuse resin member 26 disposed between the heat sink 12 and a downstream fuse portion 16 formed in the electrode lead frame 13 awith positive polarity can be controlled; therefore, the thermal conductivity and the insulation property can be controlled therebetween.After protruding from the device molding resin 20, the positive polarity electrode lead frame 13 aextends transversely along the inner surface of the heat sink 12 so as to be spaced apart from the inner surface of the heat sink 12 by a gap; thereafter, the positive polarity electrode lead frame 13 abends and then extends longitudinally toward the side starting from the heat sink 12 (toward the opening side of the case 30). The portion extending transversely so as to be spaced a gap from the inner surface of the heat sink 12 is referred to as a transversely extending portion 13 a 1 having positive polarity; the portion extending longitudinally toward the side from the heat sink 12 is referred to as a longitudinally extending portion 13 a 2 having positive polarity. The distance between the transversely extending positive polarity portion 13 a 1 and the heat sink 12 corresponds to the distance resulting from addition of the thickness of the insulating member 18 and the height of the device-facing protruding portion 12 aof the heat sink 12. The later-described securing portion 16 is formed in the transversely extending portion 13 a 1 having positive polarity.By welding, soldering or the like, the longitudinally extending portion 13 a 2 is connected to the positive polarity external terminal 10 ainserted into the insulation case 11 and formed on the insulation case 11. The external terminal 10a has a longitudinally extending portion connected to the longitudinally extending portion 13a2 and a portion extending transversely to the outside of the housing 30. The portion protruding outward from the case 30 is connected to other devices such as the positive electrode of a DC power source and the like.Similarly, the electrode lead frame 13 bhas a transversely extending negative polarity portion 13 b 1 protruding from the device molding resin 20 and then extending along the inner surface of the heat sink 12 so as to be spaced apart from the inner surface of the heat sink 12 by a gap, and a longitudinally extending negative polarity portion 13 b 2 extending toward the side from the heat sink 12. To form the securing portion 16, the length of the transversely extending portion 13 a 1 having positive polarity is greater than that of the transversely extending portion 13 b 1 having negative polarity.By welding, soldering or the like, the longitudinal extending portion 13 b 2 is connected to the negative polarity external terminal 10 b inserted into the insulation case 11 and formed on the insulation case 11. The negative polarity external terminal 10 bhas a portion extending in the longitudinal direction and connected to the negative polarity longitudinally extending portion 13 b 2 and a portion extending in the transverse direction toward the outside of the housing 30. The portion protruding outward from the case 30 is connected to other devices such as the negative electrode of the DC power source and the like.As the electrode lead frames 13 aand 13 band the external connection terminals 10 aand 10 b, a high-conductivity and high-thermal-conductivity metal such as copper, a copper alloy, or the like is used, respectively; therein, a large current flows from several amperes to several hundred amperes. It is allowed that each of the surfaces of the electrode lead frames 13 aand 13 bis coated with a metal material such as Au, Ni, or Sn.The control lead frame 21 protrudes from the sealing resin member 25 toward the opening of the case 30, and is connected to a control device for performing on / off control of the electric power semiconductor device 14.< Securing Portion 16>The fuse portion 16 functioning as a fuse is formed in the electrode wiring member 13. In the present embodiment, the fuse portion 16 is formed in a portion (in this example, the transversely extending positive polarity portion 13 a 1) of the electrode lead frame 13 that protrudes outward from the device molding resin 20. Since the fuse portion 16 is formed in the electrode lead frame 13, no additional member is required, and the cost thereof can therefore be reduced. In this example, since the fuse portion 16 is formed in the transversely extending portion of the electrode lead frame 13, it can be suppressed that, by forming the fuse portion 16, the electrode lead frame 13 becomes long in the direction (in the longitudinal direction) from the heat sink 12, and thus the height of the electric power conversion device 1 does not become large. In addition, since the fuse portion 16 is formed in the electrode lead frame 13 awith positive polarity, a current at the upstream side of the electric power semiconductor device 14 can be interrupted. Accordingly, even if a circuit abnormality occurs in the electric power semiconductor device 14, such as a short circuit between the electric power semiconductor device 14 and the case 30, the current on the upstream side thereof is allowed to be turned off and thus no excessive current is caused.The fuse portion 16 is composed of a portion of the electrode wiring member 13 having a smaller cross-sectional area than each of the portions at the before and after positions in the current flow direction. That is, the cross-sectional area of the fuse portion 16 is smaller than that of each of the portions at the positions before (upstream) and after (downstream) the fuse portion 16 in the current flow direction. As shown in FIG. 4, when an excessive current flows in the electrode lead frame 13, the current density in the fuse portion 16 having a cross-sectional area smaller than that of each of the portions at the before and after positions becomes large, and therefore the temperature of the fuse portion 16 locally rises and the fuse portion 16 melts; thus, the excessive current is cut off. The fuse portion 16 is made of gold, silver, copper or aluminum having high electric conductivity. As the fuse portion 16, a material either corresponding to or different from the other portion of the electrode lead frame 13 may be used. Although not limited to this, like the other portion of the electrode lead frame 13, the fuse portion 16 may be formed by stamping a flat plate of copper or copper alloy having a thickness of substantially 0.5 mm to 1.5 mm.The shape of the securing portion 16 may be arbitrary as long as the shape reduces the cross-sectional area. For example, as shown in FIGS. 5 and 6, the cross-sectional area may be allowed to be reduced by a notch on one side or a notch on both sides, or by a through hole. The shape of the notch or the through hole may be not only a rectangle but also any shape such as a triangle, a pentagonal, a trapezoidal, a diamond, a parallelogram, a circle, or an ellipse. It may be allowed that not only one but also two or more notches or through holes are provided. Moreover, it may be allowed that two or more notches or through holes at different positions in the longitudinal direction of the wiring are alternately arranged in zigzag or random. Two or more through holes may be arranged either in the transverse direction of the wiring or in the longitudinal direction of the wiring.< Fuse Resin Member 26>The fuse resin member 26, which is a resin member, is disposed between the fuse portion 16 and the housing 30 (the heat sink 12 in this example). As shown in FIGS. 1 and 3, the fuse resin member 26 is disposed in a range wider than that of the fuse portion 16 as viewed in the longitudinal direction. In other words, when viewed in the longitudinal direction, the arrangement area of the fuse resin 26 covers the creation area of the fuse portion 16. The fuse resin member 26 is in contact not only with the surface of the fuse portion 16 on the heat sink 12 side but also with the surface of the heat sink 12 on the fuse portion side.Before the sealing resin member 25 is filled in the case 30, the securing resin member 26 is disposed between the securing portion 16 and the case 30. The fuse resin member 26 is made of grease, an insulating sheet or an adhesive of a resin material such as silicone, epoxy or urethane resin, which has high electrical insulating ability. Moreover, the fuse resin member 26 can be formed by combining another material such as a ceramic substrate or a metal substrate having high heat resistance and high insulating ability with the aforementioned resin material. The material of the fuse resin 26 may be a material having a high thermal conductivity of, for example, 1 W / (mK) to several tens of W / (mK) as long as it is a material having a high electrical insulating property.The arrangement of the fuse resin 26 between the fuse portion 16 and the housing 30 enables the melted material of the fuse portion 16 not to come into contact with the heat sink 12 and suppresses a short circuit between the electrode wiring member 13 and the heat sink 12. In addition, since it is possible that the heat generated in the fuse portion 16 upon melting is transferred to the heat sink 12 via the fuse resin member 26, and thus the fuse portion 16 is cooled, the generated heat can be suppressed so as not to damage the electric power semiconductor device 14, the sealing resin member 25, and the like. In addition, since the fuse resin member 26 is provided for the fuse portion 16, it is possible to select a resin member from a material suitable for melting the fuse portion 16; thereby, the insulation performance and the cooling performance at the time of melting can be increased.In the present embodiment, as the securing resin member 26, a resin member having an elastic modulus lower than that of the sealing resin member 25 is used. for example, it is desirable that the elastic modulus of the securing resin member 26 be on the order of several tens of MPa (megapascals) (e.g., a value between 10 MPa and 30 MPa), and that a rubber material, a silicone rubber, or a silicone gel is used, for example. This configuration enables, when melting the fuse portion 16, the melting material which diffuses in the form of a plurality of spherical particles to be embedded in the fuse resin member 26 which has an elastic modulus lower than that of the sealing resin member 25 and which is soft so as to be held so as to be dispersed in the fuse resin member 26. This makes it possible to prevent the molten material after melting from maintaining the energy path, and thus to quickly break the energy path. Moreover, the melted material is prevented from breaking the sealing resin member 25 having a high modulus of elasticity.It is desirable that as the fuse resin member 26, a silicone resin having an arc extinguishing effect for arc discharge generated when the fuse portion 16 melts is used. This configuration makes it possible to suppress arc discharge even after melting of the fuse portion, and thus to rapidly cut off the current after melting. Accordingly, damage to the electric power semiconductor device 14, the sealing resin member 25, and the like can be suppressed.< Sealing Resin Member 25>The sealing resin member 25 is a resin member for sealing the electric power semiconductor device 14, the electrode wiring portion 13, the fuse portion 16, and the fuse resin member 26 in the case 30. The sealing resin member 25 also seals other components such as the insulating member 18 and the external terminals 10 aand 10 bin the housing 30, and a resin material having high rigidity and high thermal conductivity is used as the sealing resin member 25, for example. The sealing resin member 25 may be allowed to be formed of, for example, an epoxy resin, a silicone resin, a urethane resin, PPS, PEEK, or ABS containing heat transfer fillers. It is desirable that the elastic modulus of the sealing resin 25 has a value between 1 MPa and 50 GPa and that its thermal conductivity has a value between 0.1 W / (mK) and 20 W / (mK). The sealing resin member 25 seals the respective constituent members, so that the vibration resistance and the environmental resistance can be increased.Since the sealing resin member 25 covers the fuse portion 16 and the fuse resin member 26, the material of the fused fuse portion 16 is prevented from scattering to the outside. Since the fuse portion 16 and the fuse resin member 26 can be shut off from the outside air, arc discharge generated during the fusing operation can be prevented from causing combustion reaction, and smoke generated during the fusing operation can be prevented from escaping to the outside.Embodiment 2Next, an electric power conversion device 1 according to Embodiment 2 will be explained. The explanation for the constituent elements that are the same as those of the above Embodiment 1 will be omitted. The basic configuration of the electric power conversion device 1 according to the present embodiment is similar to that of Embodiment 1; however, a part of the configuration of a fuse resin member 26 is different. FIG. 7 is a cross-sectional view of the electric power conversion device 1 according to the present embodiment when taken at the cross-sectional position A-A in FIG. 1.As in Embodiment 1, the fuse resin member 26 is disposed between the fuse portion 16 and the housing 30 (the heat sink 12 in this example). In contrast to Embodiment 1, the fuse resin member 26 is also disposed on the fuse portion 16 on the side opposite to the housing 30 side (the heat sink 12). That is, the respective fuse resin members 26 are disposed on both sides of the fuse portion 16, i.e., on the side of the housing 30 and on the side opposite to the side of the housing 30. The side opposite to the side of the case 30 is the side outgoing from the heat sink 12, i.e., on the side of the opening of the case 30. this configuration allows the material of the fused fuse portion 16 not to contact the sealing resin member 25 and damage the sealing resin member 25.In addition, in the case where, as the fusible resin member 26, a resin member having an elastic modulus lower than that of the sealing resin member 25 is used, the molten material in the soft fusible resin member 26 can also be held on the side opposite to the housing 30 side; thereby, it becomes possible that the energy path is cut off securely and that the molten material is prevented securely from breaking the sealing resin member 25 having a high elastic modulus.In the case where a silicone resin having arc-extinguishing effect is used as the fuse resin member 26, if the fuse resin member 26 is also disposed on the side opposite to the side of the case 30, the arc-extinguishing effect for arc discharge can be further increased; thus, the current after melting can be cut off more quickly.In the present embodiment, the fuse resin members 26 are also disposed on both sides of the fuse portion 16; that is, the fuse resin members 26 are disposed so as to cover the entire periphery of the fuse portion 16. This arrangement makes it possible to further enhance the suppressing effect of the securing resin 26 for damage to the sealing resin member 25, safety in cutting the energy path, arc extinguishing effect, and the like.Embodiment 3Next, an electric power conversion device 1 according to Embodiment 3 will be explained. The explanation for the constituent elements that are the same as those of the above Embodiment 1 will be omitted. The basic configuration of the electric power conversion device 1 according to the present embodiment is similar to that of Embodiment 1; however, a part of each of the configurations of a heat sink 12 and a fuse resin member 26 is different. FIG. 8 is a cross-sectional view of the electric power conversion device 1 according to the present embodiment when taken at the cross-sectional position A-A in FIG. 1.As in Embodiment 1, the fuse resin member 26 is disposed between the fuse portion 16 and the housing 30 (the heat sink 12 in this example). However, unlike Embodiment 1, a protruded fuse portion 12 bprotruding toward the fuse portion 16 side (inward) is provided in an inner surface portion of the housing 30 (in this example, the heat sink 12) opposing the fuse portion 16. The protruding securing portion 12 bis formed in a flat plate shape. As viewed in the longitudinal direction, the fuse-facing protruding portion 12 bis formed in an area as large as the arrangement area of the fuse resin member 26. Since the thickness of the fuse resin member 26 can be reduced, it becomes possible that the heat transfer from the fuse portion 16 to the heat sink 12 through the fuse resin member 26 is further increased, and thus the suppression of damage to the electric power semiconductor device 14, the sealing resin member 25, and the like caused by the heat generated upon melting is further increased. Moreover, a balance between the thermal conductivity and the insulating property can be achieved by adjusting the protruding height of the fuse-facing protruding portion 12 b.As in Embodiment 3, it may be allowed that the fuse resin members 26 are also disposed on a portion of the fuse portion 16 located on the side opposite to the side of the case 30 (the heat sink 12), or that the fuse resin members 26 are disposed so as to cover the entire periphery of the fuse portion 16.[Other Embodiments]Finally, further embodiments of the present invention will be explained. Each of the embodiment configurations to be explained below is not limited to being used separately, but may be used in combination with the configurations of other embodiments as long as no discrepancy occurs.(1) In each of the above embodiments, the case where the electric power semiconductor device 14 and the electrode lead frames 13 as electrode wiring members 13 are sealed with the device molding resin 20 which is a resin member, so that the semiconductor device module 29 is obtained has been explained as an example. However, embodiments of the present invention are not limited to the aforementioned case. In other words, it is not necessary that the electric power semiconductor device 14 and the electrode wiring member 13 be sealed with the device molding resin 20, so that the semiconductor device module 29 is packaged. That is, the electric power semiconductor device 14, the electrode wiring member 13, and the like that are not sealed with the device molding resin 20 can be allowed to be sealed in the case 30 with the sealing resin member 25. In this case, it may be allowed that the electrode wiring member 13 is a bus bar or the like and that the fuse portion 16 is formed in a portion of one of the positive polarity electrode wiring members and the negative polarity electrode wiring member sealed with the sealing resin member 25.(2) In each of the above-mentioned embodiments, the case where the fuse portion 16 is formed in the positive-pole electrode lead frame 13 a(the transverse direction extending portion 13 a 1) has been explained as an example. However, embodiments of the present invention are not limited to the aforementioned case. In other words, the fuse portion 16 may be allowed to be formed in any portion as long as it is a portion of the electrode wiring member 13 connected to the main electrode of the electric power semiconductor device 14 and sealed with the sealing resin member 25. For example, it may be allowed that the fuse portion 16 is formed in the transverse direction extending portion 13 b 1 of the electrode lead frame 13 bhaving negative polarity, the longitudinal direction extending portion 13 a 2 having positive polarity, the longitudinal direction extending portion 13 b 2 having negative polarity, or one of the external connection terminals 10 ahaving positive polarity and 10 bhaving negative polarity.(3) In each of the above embodiments, the case where the electric power conversion device 1 is provided with a single electric power semiconductor device 14 (switching device) has been explained as an example. However, embodiments of the present invention are not limited to the above case. That is, the electric power conversion device 1 may be allowed to be provided with two or more electric power semiconductor devices. For example, it may be allowable that between a wiring member having a positive polarity electrode and a wiring member having a negative polarity electrode, two switching devices are connected in series with each other, and the fuse portion 16 is formed in the wiring member having the positive or negative polarity electrode. In addition, it may be allowable that a bridge circuit in which two or more sets of series circuits each including two switching devices are connected in parallel with each other is disposed between a wiring member having a positive polarity electrode and a wiring member having a negative polarity electrode, and that the fuse portion 16 is formed in the wiring member having the electrode for each of the two or more sets of series circuits. All or a part of the electric power semiconductor devices 14 may be allowed to be diodes.Within the scope of the present invention, the embodiments thereof can be freely combined with one another and can be changed or omitted accordingly.REFERENCE CHARACTER LIST1 Electric power conversion device. 12 bprotruding fuse portion 13 electrode wiring member 14 electric power semiconductor device 16 fuse portion 20 device mold resin 25 sealing resin member 26 fuse resin member 29 semiconductor device module 30 case

Claims

An electric power conversion device (1) comprising: an electric power semiconductor device (14); an electrode wiring member (13) connected to a main electrode of the electric power semiconductor device (14); a case (30); a fuse portion (16) formed in the electrode wiring member (13) and functioning as a fuse; a fuse resin member (26) being a resin member disposed between the fuse portion (16) and the case (30); and a sealing resin member (25) which is a resin member for sealing the electric power semiconductor device (14), the electrode wiring member (13), the fuse portion (16), and the fuse resin member (26) in the case (30), wherein the fuse portion (16) is formed of a portion of the electrode wiring member (13) having a cross-sectional area smaller than that of each of the portions at the before and after positions thereof in the flow direction of a current.The electric power conversion device (1) according to claim 1, wherein the electric power semiconductor device (14) and electrode lead frames (13) are sealed, as the electrode wiring members (13), with a device molding resin (20) that is a resin member, so that a semiconductor device module (29) is obtained, and wherein the fuse portion (16) is formed in a portion of the electrode lead frame that protrudes outward from the device molding resin (20).The electric power conversion device (1) according to any one of claims 1 and 2, wherein the housing (30) comprises a metallic heat sink (12), wherein the fuse portion (16) extends along the heat sink (12) so as to be spaced apart from the heat sink (12) by a gap, and wherein the sealing resin member (25) is disposed between the fuse portion (16) and the heat sink (12) and is in contact with the fuse portion (16) and the heat sink (12).The electric power conversion device (1) according to any one of claims 1 to 3, wherein the fuse resin member (26) is also disposed on a portion of the fuse portion (16) that is on the side opposite to the side of the housing (30).The electric power conversion device (1) according to any one of claims 1 to 4, wherein the fuse resin member (26) is disposed so as to cover the entire periphery of the fuse portion (16).The electric power conversion device (1) according to any one of claims 1 to 5, wherein the fuse resin member (26) has an elastic modulus lower than that of the sealing resin member (25).The electric power conversion device (1) according to any one of claims 1 to 6, wherein the elastic modulus of the securing resin member (26) is on the order of tens of megapascals.The electric power conversion device (1) according to any one of claims 1 to 7, wherein as the fuse resin member (26), a silicone resin having an arc extinguishing effect for arc discharge generated when the fuse portion (16) melts is used.The electric power conversion device (1) according to any one of claims 1 to 8, wherein a fuse-facing protruding portion, which is a protruding portion protruding toward the fuse portion (16) side, is provided in an inner surface portion of the housing (30) facing the fuse portion (16).The electric power conversion device (1) according to any one of claims 1 to 9, wherein the housing (30) is formed in the shape of a bottomed tube whose bottom portion includes a metallic heat sink (12), and wherein the fuse resin member (26) is disposed between the fuse portion (16) and the heat sink (12).

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