Power conversion device

Abstract

To downsize a power conversion device by considering heat dissipation of a heating component.SOLUTION: Power conversion equipment comprises a housing and a heat dissipation structure. Inside the housing is formed a flow channel for coolant running in a plane along a cooling surface. The heat dissipation structure includes a plurality of power semiconductors, a resin stationary plate, and a plurality of heat conductive sheets. Each power semiconductor has a heat dissipation surface that is not insulated electrically. The resin stationary plate is formed in a flat plate shape using resin material having an electric insulation property and has a first principal surface to which the respective power semiconductors are fixed. The respective heat conductive sheets have their first portions between the resin stationary plate and heat radiation surfaces of the respective power semiconductors. The first principal surface of the resin stationary plate extends in a direction away from the cooling surface of the housing. Each heat conductive sheet has a first portion extending in a direction from a portion connected with a heat radiation surface of a corresponding power semiconductor to the cooling surface of the housing, and a second portion extending from the first portion's side of the cooling surface along the cooling surface of the housing and being thermally connected to the cooling surface.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a power conversion device. [Background technology]

[0002] Conventionally, there is a demand for miniaturization of power conversion devices such as chargers installed in electric vehicles, etc., due to, for example, limitations on installation space. Under such circumstances, when converting high current and high voltage power, power loss in electronic components installed in the power conversion device, such as power semiconductors, increases, and heat generation from these electronic components also increases. For this reason, there is a demand for technology that can efficiently dissipate heat from heat-generating components (electronic components) installed in the power conversion device.

[0003] For example, Patent Document 1 discloses a technology for a power supply device that aims to reduce the size of the entire device while ensuring heat dissipation from heat-generating components. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2019 / 208250 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when using a liquid cooling system as a heat dissipation method, for example, when a structure is used in which a horizontal flow path branches into a vertical flow path to match the arrangement of power semiconductors, the coolant may stagnate within the flow path, making it impossible to dissipate heat efficiently. For this reason, there is room for improvement in terms of heat dissipation from heat-generating components such as power semiconductors.

[0006] One of the problems that the present disclosure aims to solve is to reduce the size of a power conversion device while taking into consideration the heat dissipation properties of heat-generating components. [Means for solving the problem]

[0007] The power conversion device according to the present disclosure includes a housing and a heat dissipation structure. The housing has a flow path for a coolant formed therein, the flow path running along a cooling surface. The heat dissipation structure is disposed on the cooling surface of the housing. The heat dissipation structure includes a plurality of power semiconductors, a resin fixing plate, and a plurality of thermally conductive sheets. The heat dissipation surface of each of the plurality of power semiconductors is not electrically insulated. The resin fixing plate is formed in a flat plate shape using an electrically insulating resin material, and each of the plurality of power semiconductors is fixed to a first main surface. Each of the plurality of thermally conductive sheets has thermal conductivity. First portions of each of the plurality of thermally conductive sheets are disposed between the heat dissipation surfaces of the plurality of power semiconductors and the resin fixing plate. When the heat dissipation structure is disposed on the cooling surface of the housing, the first main surface of the resin fixing plate extends in a direction away from the cooling surface of the housing. The first portion of each of the plurality of thermally conductive sheets is thermally connected to the corresponding heat dissipation surface and extends from the connection portion with the heat dissipation surface along the first main surface of the resin fixing plate in a direction toward the cooling surface of the housing, and the second portion of each of the plurality of thermally conductive sheets extends from the cooling surface side of the corresponding first portion along the cooling surface of the housing in a direction away from the resin fixing plate and is thermally connected to the cooling surface. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to reduce the size of a power conversion device by taking into consideration the heat dissipation properties of heat-generating components. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of a circuit configuration including a power semiconductor mounted on a power conversion device according to an embodiment. [Figure 2] FIG. 2 is a front view showing an example of the configuration of a heat dissipation structure of the power conversion device according to the embodiment. [Figure 3] FIG. 3 is a top view showing an example of the configuration of the heat dissipation structure of FIG. [Figure 4] FIG. 4 is a cross-sectional view showing an example of the configuration of the heat dissipation structure of FIG. [Figure 5] FIG. 5 is a cross-sectional view showing another example of the configuration of the heat dissipation structure of the power converter according to the embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing another example of the configuration of the heat dissipation structure of the power converter according to the embodiment. [Figure 7] FIG. 7 is a cross-sectional view showing another example of the configuration of the heat dissipation structure of the power converter according to the embodiment. [Figure 8] FIG. 8 is a cross-sectional view showing another example of the configuration of the heat dissipation structure of the power conversion device according to the embodiment. [Figure 9] FIG. 9 is a cross-sectional view showing another example of the configuration of the heat dissipation structure of the power converter according to the embodiment. [Figure 10] FIG. 10 is a cross-sectional view showing another example of the configuration of the heat dissipation structure of the power converter according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of a heat dissipation structure, a power conversion device, and a vehicle according to the present disclosure will be described with reference to the drawings.

[0011] In the description of the present disclosure, components having the same or substantially the same functions as those described above with respect to the previously-mentioned drawings may be given the same reference numerals, and descriptions thereof may be omitted as appropriate. Furthermore, even when the same or substantially the same parts are shown, the dimensions and proportions may be different depending on the drawing. Furthermore, for example, in order to ensure the visibility of the drawings, reference numerals may be given to only the main components in the description of each drawing, and reference numerals may not be given to components having the same or substantially the same functions as those described above with respect to the previously-mentioned drawings.

[0012] In the description of the present disclosure, components having the same or substantially the same functions may be distinguished by adding an alphanumeric character to the end of the reference symbol. Alternatively, when multiple components having the same or substantially the same functions are not distinguished, they may be collectively described by omitting the alphanumeric character at the end of the reference symbol.

[0013] In the description of this disclosure, expressions such as orthogonal, horizontal, vertical, and parallel do not necessarily mean strictly orthogonal, horizontal, vertical, and parallel, but also include cases where they can be regarded as orthogonal, horizontal, vertical, and parallel.

[0014] The heat dissipation structure according to the present disclosure is a structure for dissipating heat from electronic components (heat-generating components) such as power semiconductors that generate heat due to power loss in an electronic device such as a power converter to a housing or the outside. This heat dissipation structure is mounted on an electronic device such as a power converter in a modularized state, for example, but is not limited to this. Some or all of the components of the heat dissipation structure may be individually assembled into the housing of the electronic device such as a power converter.

[0015] The electronic component to be dissipated heat is, for example, a power semiconductor such as a MOSFET, but is not limited to this. The electronic component to be dissipated heat may be a semiconductor element, a semiconductor module, a magnetic body, a capacitor, a circuit breaker, or other components. A semiconductor module is, for example, composed of multiple semiconductor elements. Here, the magnetic body is a transformer, a transformer-integrated printed circuit board, a transformer, a reactor, or a choke. The circuit breaker is a relay or a fuse.

[0016] The power conversion device according to the present disclosure may be mounted on a vehicle, for example, as an on-board charger. For example, the power conversion device may be an on-board charger that converts AC power supplied from an external single-phase or three-phase AC power source into DC power and supplies the converted DC power to a load mounted on the vehicle. The load may be, for example, a battery, an inverter, a motor, or various electrical components.

[0017] The vehicle may be any type of moving body configured to be driven or to drive its accessories (electrical components) using power from a battery, such as a passenger car, a freight vehicle, a van, a motorcycle, or an electric kick scooter. Examples of such electrical components include a navigation system, an audio system, an air conditioner, a power window, a defogger, an ECU (Electronic Control Unit), a GPS (Global Positioning System) module, and an on-board camera. The vehicle battery may be any battery capable of storing power for driving the traction motor (main motor) and electrical components mounted on the vehicle, and any battery, such as a lithium-ion battery, a nickel-metal hydride battery, or an all-solid-state battery, may be used. The power conversion device according to the present disclosure is not limited to vehicles, and may also be installed in, for example, aircraft, amusement facilities, uninterruptible power supplies, and the like.

[0018] A power conversion device according to the present disclosure is provided with, for example, a power factor correction (PFC) circuit that rectifies and smooths AC voltage from an external AC power supply to generate a DC voltage. Furthermore, for example, a DC-DC conversion circuit is provided downstream of the PFC circuit that converts the DC voltage generated by the PFC circuit back into AC voltage and then rectifies and smooths the converted AC voltage to generate a DC voltage of an arbitrary set voltage. Furthermore, for example, a noise filter is provided upstream of the PFC circuit to suppress (remove) noise from entering the power conversion device from the external AC power supply and from leaking noise from the power conversion device to the AC power supply.

[0019] (First embodiment) Fig. 1 is a diagram showing an example of a circuit configuration 2 mounted on a power conversion device 1 according to an embodiment. As shown in Fig. 1, a circuit configuration 2 including a plurality of MOSFETs 23 (power semiconductors) is mounted on a PFC circuit or a DC-DC conversion circuit of the power conversion device 1 according to an embodiment.

[0020] 1 illustrates four full-bridge-connected MOSFETs 23a to 23d as the multiple MOSFETs 23. The drains of the high-side MOSFETs 23a and 23c are electrically connected to the power line 21a at a "DC+" potential. The sources of the low-side MOSFETs 23b and 23d are electrically connected to the power line 21b at a "DC-" potential. The gates of the MOSFETs 23a to 23d are electrically connected to a control circuit (not shown) of the power conversion device 1. The load circuit 9 is electrically connected between the sources of the high-side MOSFETs 23a and 23c, i.e., between the drains of the low-side MOSFETs 23b and 23d.

[0021] Each of the multiple MOSFETs 23 is driven at a different potential. Therefore, it is necessary to insulate the area in which each of the multiple MOSFETs 23 is provided. In the example of Fig. 1, the area R1 in which MOSFET 23a is provided, the area R2 in which MOSFET 23b is provided, the area R3 in which MOSFET 23c is provided, and the area R4 in which MOSFET 23d is provided are insulated from each other.

[0022] As an example, the circuit configuration 2 in Fig. 1 is implemented as a circuit configuration on the primary side of a DC-DC conversion circuit. That is, the electronic components to be dissipated by the heat dissipation structure 3 according to the present disclosure (described later) are, for example, multiple MOSFETs on the primary side of the DC-DC conversion circuit. The multiple MOSFETs on the primary side convert, for example, a DC voltage smoothed by an output capacitor (e.g., an electrolytic capacitor) of the PFC circuit into an AC voltage by switching operations controlled by a control circuit (not shown) of the power conversion device 1. For example, the load circuit 9 is a transformer that transfers the energy of the single-phase AC voltage generated by the multiple MOSFETs on the primary side to the secondary side.

[0023] 1 may be implemented as a circuit configuration on the secondary side of a DC-DC conversion circuit. That is, the electronic components to be dissipated by the heat dissipation structure 3 according to the present disclosure, which will be described later, may be, for example, multiple MOSFETs on the secondary side of the DC-DC conversion circuit. The multiple MOSFETs on the secondary side rectify, for example, a single-phase AC voltage transmitted via a transformer by switching operations controlled by a control circuit (not shown) of the power conversion device 1. In this case, the load circuit 9 may be, for example, a transformer.

[0024] 1 may be implemented as a circuit configuration for each phase of a PFC circuit. That is, the electronic components to be dissipated by a heat dissipation structure 3 according to the present disclosure (described later) may be multiple MOSFETs in the PFC circuit. The multiple MOSFETs in the PFC circuit rectify, for example, an AC voltage from an external AC power supply by switching operations controlled by a control circuit (not shown) of the power conversion device 1. In this case, the load circuit 9 may be, for example, a noise filter for each phase.

[0025] The circuit configuration 2 including the multiple MOSFETs 23 (power semiconductors) mounted in the power conversion device 1 according to the embodiment is not limited to the configuration exemplified in FIG. 1 and can be modified as appropriate.

[0026] The control circuit (not shown) of the power conversion device 1 may have, for example, at least one processor and at least one memory, and may be configured as hardware using a conventional computer. For example, a CPU (Central Processing Unit) may be used as this processor. The processor executes programs, for example, to comprehensively control the operation of the control circuit and realize various functions of the control circuit. For example, the processor may load programs stored in a ROM (Read Only Memory) or the like into a RAM (Random Access Memory) and execute the loaded programs to realize the various functions of the control circuit. Alternatively, some or all of the functions may be realized by dedicated hardware circuits (such as semiconductor integrated circuits).

[0027] The control circuit (not shown) of the power conversion device 1 may be realized by a computer such as an ECU (Electronic Control Unit) provided inside the vehicle, a DCU (Domain Control Unit) such as a CDC (Cockpit Domain Controller) integrating multiple ECUs, or an OBU (On Board Unit).The control circuit may transmit and receive information to and from other ECUs mounted on the vehicle or an external power supply (AC power supply) connected to the vehicle via an in-vehicle network including a CAN (Controller Area Network), Ethernet (registered trademark), or USB (Universal Serial Bus (registered trademark)).The control circuit may also communicate with an information processing device outside the vehicle via a network such as the Internet.

[0028] Here, the heat dissipation structure 3 of the power conversion device 1 according to this embodiment will be described in detail with reference to the drawings.

[0029] Fig. 2 is a front view showing an example of the configuration of the heat dissipation structure 3 of the power conversion device 1 according to the embodiment. Fig. 3 is a top view showing an example of the configuration of the heat dissipation structure 3 of Fig. 2. Fig. 4 is a cross-sectional view showing an example of the configuration of the heat dissipation structure 3 of Fig. 2. Fig. 3 shows a cross section of the IV-IV plane (YZ plane) of Fig. 2 as viewed from the lower side (-X side) of the paper.

[0030] 2 to 4, the heat dissipation structure 3 is disposed in a metal housing 41. Specifically, the heat dissipation structure 3 is disposed on the cooling surface on the upper surface side (+Z side) of the metal housing 41. Note that other electronic components of the power conversion device 1, such as a transformer, are also disposed on the cooling surface of the metal housing 41.

[0031] The heat dissipation structure 3 and the cooling surface of the metal housing 41 are thermally connected. Here, being thermally connected means being configured to allow heat exchange. Heat transfer between the heat dissipation structure 3 and the metal housing 41 is achieved by, for example, thermal conduction, but other forms may be used in addition to or instead of thermal conduction. Heat transfer between the heat dissipation structure 3 and the metal housing 41 may also be achieved via other components.

[0032] The metal housing 41 constitutes a part of the housing of the power conversion device 1. The metal housing 41 is a flat member extending along the XY plane. The metal housing 41 is formed of a metal material such as die-cast. Note that the metal housing 41 may be formed of other alloys, other metals than alloys, or non-metallic materials as long as it can transport heat from mounted components such as the heat dissipation structure 3 that are thermally connected to the cooling surface on the upper surface side (+Z side) of the metal housing 41 directly or via other members to the coolant flowing through the flow paths 43 inside the metal housing 41.

[0033] 2 and 4, a coolant flow path 43 is formed inside the metal casing 41. The metal casing 41 and the flow path 43 constitute a liquid-cooling type cooling mechanism that uses a coolant such as antifreeze as the working fluid. Specifically, in the metal casing 41, the flow path 43 extends in a direction (for example, horizontally) along the cooling surface (XY plane). In other words, the metal casing 41 has the flow path 43 formed therein, running within one surface (cooling surface).

[0034] The flow paths 43 may branch in at least two directions along the XY plane. On the other hand, the flow paths 43 do not branch in the direction along the Z direction. In other words, if an intersection where at least two flow paths 43 intersect is present in the metal casing 41, each flow path 43 extends from the intersection in a direction along the XY plane, but does not extend in a direction along the Z direction. In this way, the power conversion device 1 according to the present disclosure can configure a cooling mechanism for the entire system using flow paths 43 that run only within one plane (the XY plane).

[0035] The cooling mechanism may be a component of the heat dissipation structure 3. That is, the heat dissipation structure 3 according to the present disclosure may further include a metal casing 41 and a flow path 43. In other words, the heat dissipation structure 3 according to the present disclosure may be configured to dissipate heat from each of the plurality of MOSFETs 23, which are heat-generating components, to the cooling surface on the upper surface side (+Z side) of the metal casing 41, which is the cooling surface of the cooling mechanism, or may be configured to dissipate heat to the outside of the power conversion device 1 via a coolant flowing through a flow path 43 running inside the metal casing 41, which is the cooling mechanism.

[0036] As an example, the heat dissipation structure 3 is arranged on the cooling surface of the metal housing 41 of the power conversion device 1, with its components assembled together (modularized). For example, the heat dissipation structure 3 is detachably fixed on the cooling surface of the metal housing 41 by fixing members (not shown) such as screws.

[0037] 2 to 4, the heat dissipation structure 3 includes a plurality of MOSFETs 23, a resin fixing plate 51, a plurality of thermally conductive sheets 71, and an insulating layer-equipped metal plate 75. Here, the insulating layer-equipped metal plate 75 according to the embodiment is an example of a first plate-shaped member.

[0038] The resin fixing plate 51 is a member formed in a flat plate shape. The resin fixing plate 51 is made of any resin material having electrical insulation properties. The resin material may be appropriately selected by comprehensively considering the balance between its characteristics, processability, miniaturization effect, cost, and other factors. The characteristics of the resin material may be appropriately considered, such as the operating voltage of the circuit configuration 2, the tracking resistance index (CTI) of the resin material, or the creepage distance based on the CTI. Examples of resin materials that can be used include PBT (polybutylene terephthalate) resin, PA (polyamide) resin, and PPS (polyphenylene sulfide) resin. The size of the resin fixing plate 51 may be appropriately selected, for example, depending on the characteristics of the resin material and the arrangement of the components to be fixed to the resin fixing plate 51, such as the spacing between the multiple MOSFETs 23. The size of the resin fixing plate 51 may be determined not only based on the arrangement of the components to be fixed, but also on the arrangement of other electronic components to be fixed near the resin fixing plate 51. The main surface of the resin fixing plate 51 may be inclined with respect to the ZX plane. That is, the resin fixing plate 51 is, for example, perpendicular to the cooling surface of the metal housing 41, but can be appropriately inclined with respect to the cooling surface of the metal housing 41 depending on, for example, restrictions in the height direction (Z direction) and the layout of each component.

[0039] As shown in FIGS. 2 to 4, the resin fixing plate 51 is disposed on the cooling surface of the metal casing 41. The main surface (ZX plane) of the resin fixing plate 51 extends in a direction away from the cooling surface of the metal casing 41. This direction away from the cooling surface of the metal casing 41 is, for example, a direction (Z direction) perpendicular to the cooling surface of the metal casing 41. As an example, the resin fixing plate 51 is disposed on the cooling surface of the metal casing 41 in a modularized state with a plurality of MOSFETs 23 and the like attached thereto, as will be described later. The resin fixing plate 51 disposed on the cooling surface of the metal casing 41 is detachably fixed to the metal casing 41 by fixing members (not shown) such as screws. When screws are used as the fixing members, the screws may be metal screws or resin screws.

[0040] At least one (first main surface) of the main surfaces (ZX surfaces) of the resin fixing plate 51 is provided with fixing portions for attaching each of the plurality of MOSFETs 23. The fixing portions of the resin fixing plate 51 support the plurality of MOSFETs 23. As shown in FIGS. 2 to 4, the fixing portions according to this embodiment are formed as grooves 511 recessed in a shape that follows the outline (e.g., width) of the MOSFETs 23. The grooves 511 extend in the main surface (ZX surface) of the resin fixing plate 51 in a direction away from the cooling surface of the metal casing 41. The direction away from the main surface (ZX surface) of the resin fixing plate 51 is, for example, a direction (Z direction) perpendicular to the cooling surface of the metal casing 41.

[0041] The grooves 511 may extend in a direction deviating from the Z direction. That is, the MOSFET 23 may be arranged such that its heat dissipation surface 235 is aligned along the main surface of the resin fixing plate 51, and may be tilted as appropriate depending on, for example, the connection of the leads 233 to the drive board. As an example, the MOSFET 23 may be arranged on the resin fixing plate 51 with its leads 233 extending in the X direction.

[0042] The grooves 511 may be provided not only on one first main surface (for example, the -Y side) of the resin fixing plate 51 but also on the other second main surface (for example, the +Y side). That is, the resin fixing plate 51 may support a plurality of MOSFETs 23 on both main surfaces thereof.

[0043] 2 and 4, holes 513 penetrating between both main surfaces are provided on the cooling surface side (-Z side) of the resin fixing plate 51. Providing these holes 513 reduces the weight of the resin fixing plate 51, and when the MOSFETs 23 are attached to both main surfaces of the resin fixing plate 51, the insulating layer-provided metal plate 75 can be shared between the MOSFETs 23 on both sides.

[0044] 2 to 4, the MOSFET 23 is disposed in the groove 511 (fixing portion) of the resin fixing plate 51. The heat dissipation surface 235 of the fixed MOSFET 23 faces the resin fixing plate 51. The leads 233 of the fixed MOSFET 23 extend upward (e.g., in the Z direction) along the main surface of the resin fixing plate 51, and are electrically connected to a drive board (not shown). In this way, in the heat dissipation structure 3 according to this embodiment, the heat dissipation surface 235 of each of the multiple MOSFETs 23 is perpendicular to the cooling surface of the metal casing 41, that is, the MOSFETs 23 are placed vertically.

[0045] Specifically, MOSFET 23 is fixed to resin fixing plate 51 by fixing members 6 inserted into fixing holes in main body 231. Fixing members 6 are, for example, metal screws, but may also be resin screws.

[0046] Furthermore, the heat dissipation surface 235 of the MOSFET 23 is not electrically insulated. As an example, an insulating layer having electrical insulation properties is not formed on the heat dissipation surface 235 of the MOSFET 23. As an example, the MOSFET 23 does not have package insulation. Note that the MOSFET 23 may have package insulation. Here, package insulation refers to molding (insert molding) an electronic component with insulating resin. In other words, the heat-generating component according to the present disclosure, i.e., the electronic component to be dissipated heat by the heat dissipation structure 3, may be an electronic component that is not molded with insulating resin, i.e., is not insulated.

[0047] The thermally conductive sheet 71 is a sheet-shaped member made of a thermally conductive material. The thermally conductive sheet 71 is made of a carbon-based material such as graphite, and has high thermal conductivity for heat transport in the planar direction. In other words, the thermally conductive sheet 71 has high thermal conductivity for heat transport between the first portion 711 and the second portion 713. The thermally conductive sheet 71 is preferably made of a carbon-based material with high thermal conductivity, but may also be made of metal.

[0048] As shown in FIGS. 2 to 4 , the multiple thermally conductive sheets 71 are disposed between the heat dissipation surfaces 235 of the multiple MOSFETs 23 and the grooves 511 (fixing portions) of the resin fixing plate 51. That is, each of the multiple MOSFETs 23 is fixed to the resin fixing plate 51 via a corresponding thermally conductive sheet 71. A thermally conductive sheet 71 is provided for each area of ​​the MOSFETs 23 that are driven at different potentials. Here, the heat dissipation surface 235 of each MOSFET 23 is in contact with the first portion 711 of the corresponding thermally conductive sheet 71. Specifically, the heat dissipation surface of each of the multiple MOSFETs 23 is thermally connected to the first portion 711 of the corresponding thermally conductive sheet 71. Here, the first portion 711 of the thermally conductive sheet 71 is a portion of the thermally conductive sheet 71 that is disposed along the heat dissipation surfaces 235 of the MOSFETs 23 and the resin fixing plate 51. That is, the first portion 711 of the heat conduction sheet 71 extends from the connection portion with the heat dissipation surface 235 of the MOSFET 23 along the ZX plane toward the cooling surface of the metal casing 41 (-Z side). Also, as shown in FIGS. 2 to 4, the second portion 713 of the heat conduction sheet 71 is a portion of the heat conduction sheet 71 that is arranged along the metal casing 41. That is, the second portion 713 of the heat conduction sheet 71 extends from the cooling surface side (-Z side) of the metal casing 41 of the first portion 711 in a direction away from the resin fixing plate 51 along the XY plane. This second portion 713 of the heat conduction sheet 71 is thermally connected to the cooling surface of the metal casing 41, as will be described later.

[0049] In this way, the thermally conductive sheet 71 is bent in a substantially L-shape and arranged so as to follow the heat dissipation surface 235 of the MOSFET 23, the resin fixing plate 51, and the metal casing 41. That is, each of the multiple thermally conductive sheets 71 can guide heat from the heat dissipation surface 235 of each MOSFET 23 arranged vertically along the resin fixing plate 51 to the surface along the cooling surface of the metal casing 41 where the horizontal flow path 43 is formed. As a result, the heat transfer surface from the thermally conductive sheet 71 to the metal casing 41 is enlarged by the second portion 713 of the thermally conductive sheet 71. In other words, the projection area on the cooling surface of the metal casing 41 of the heat transport path from the heat dissipation surface 235 of each MOSFET 23 arranged vertically along the resin fixing plate 51 to the metal casing 41 is enlarged by the second portion 713 of the thermally conductive sheet 71.

[0050] Note that the distance between the second portions 713 of each thermally conductive sheet 71 and adjacent thermally conductive sheets 71 is limited to ensure an insulating distance. On the other hand, the second portions 713 of each thermally conductive sheet 71 can improve their heat dissipation efficiency by expanding their heat transfer surface in the direction away from the resin fixing plate 51 (-Y direction). As an example, the second portions 713 of each thermally conductive sheet 71 are larger than the heat dissipation surface 235 of the MOSFET 23. This "larger" means that the area of ​​the second portion in the plane along the cooling surface of the metal casing 41 (XY plane) is larger than the area of ​​the heat dissipation surface 235 in the plane along the resin fixing plate 51 (ZX plane).

[0051] The metal plate with an insulating layer 75 is a member formed in a flat plate shape. The metal plate with an insulating layer 75 is formed using a thermally conductive material such as aluminum. The metal plate with an insulating layer 75 has thermal conductivity at least in the thickness direction (Z direction). The metal plate with an insulating layer 75 is only required to transport heat from the MOSFET 23, which is thermally connected to its upper surface side (+Z side) directly or via another member, to its lower surface side (-Z side), and may be formed from other metals such as copper, alloys, or non-metallic materials. Preferably, the metal plate with an insulating layer 75 also has thermal conductivity in directions along the main surface (XY plane) and functions as a heat diffusion plate (heat capacity).

[0052] An insulating layer having electrical insulation properties is formed on at least the upper surface (the surface on the +Z side) of the outer surfaces of the insulating layer-equipped metal plate 75. This insulating layer provides insulation between the multiple thermally conductive sheets 71 electrically connected to the multiple MOSFETs 23. In other words, an insulating treatment is applied to at least the upper surface of the insulating layer-equipped metal plate 75 to form an insulating layer. The insulating treatment is a process of forming a layer of insulating material such as resin on the outer surface of the metal plate by, for example, a process such as heat pressing or powder coating.

[0053] As shown in FIGS. 2 to 4 , the upper surface (+Z side surface) of the metal plate with insulation layer 75 faces the lower surfaces (−Z side surface) of the second portions 713 of the thermally conductive sheets 71. That is, the metal plate with insulation layer 75 is disposed between the second portions 713 of the thermally conductive sheets 71 and the cooling surface of the metal casing 41, spanning the second portions 713. The metal plate with insulation layer 75 is thermally connected to each of the second portions 713 of the thermally conductive sheets 71. Specifically, each of the second portions 713 of the thermally conductive sheets 71 is fixed to the upper surface of the metal plate with insulation layer 75 with an adhesive 73. That is, the metal plate with insulation layer 75 transports heat from the MOSFETs 23 thermally connected to its upper surface (+Z side) via the adhesive 73 and the thermally conductive sheets 71 to its lower surface (−Z side).

[0054] The adhesive 73 that bonds each of the second portions 713 of the thermally conductive sheets 71 to the metal plate 75 with an insulation layer has at least thermal conductivity (heat dissipation). The adhesive 73 may also have electrical insulation. In this case, the metal plate 75 with an insulation layer does not need to be provided with an insulating layer.

[0055] As shown in FIGS. 2 to 4 , the lower surface (the surface on the −Z side) of the metal plate with insulation layer 75 faces the cooling surface (the surface on the +Z side) of the metal casing 41. That is, the metal plate with insulation layer 75 is arranged in the metal casing 41 so that its main surface (the XY plane) extends horizontally to the cooling surface. The metal plate with insulation layer 75 is also thermally connected to the cooling surface of the metal casing 41. Specifically, the lower surface of the metal plate with insulation layer 75 is arranged on the cooling surface of the metal casing 41 via thermal grease 77. The metal plate with insulation layer 75 arranged on the cooling surface of the metal casing 41 may be fixed to the metal casing 41 by a fixing member (not shown) such as a screw. When a screw is used as the fixing member, the screw may be a metal screw or a resin screw.

[0056] The thermal grease 77 provided between the cooling surface of the metal casing 41 and the insulating layer-equipped metal plate 75 has at least thermal conductivity (heat dissipation properties). Note that the thermal grease 77 may further have electrical insulation properties.

[0057] The metal plate with an insulating layer 75 may be indirectly fixed onto the cooling surface of the metal housing 41. As an example, the metal plate with an insulating layer 75 may be fixed to a resin fixing plate 51, and the resin fixing plate 51 may be fixed onto the cooling surface of the metal housing 41, thereby being thermally connected to the cooling surface.

[0058] Furthermore, the thermally conductive sheet 71 and the insulating layer-attached metal plate 75, which are bonded by the adhesive 73, may be fixed to the metal housing 41 by a fixing member (not shown) such as a screw. In this case, when a screw is used as the fixing member, the screw is a resin screw.

[0059] As described above, the heat dissipation structure 3 according to this embodiment has high thermal conductivity in the planar direction and includes the thermal conduction sheet 71 arranged in an L-shape. With this configuration, heat can be dissipated with low thermal resistance from each of the multiple MOSFETs 23 arranged vertically along a vertical plane (ZX plane) to the horizontal plane (XY plane) along the cooling surface of the metal casing 41.

[0060] Therefore, with the above configuration, a vertical water channel is not required in the metal casing 41, enabling a structural design with high packaging density, and the fixing plate can be realized by the resin fixing plate 51 made of resin. Furthermore, with the above configuration, the resin fixing plate 51 can be included in the sub-assembly (modularization), improving manufacturability. Furthermore, since a vertical water channel is not required, the flow path design can be simplified and reduced in cost, and a decrease in heat dissipation efficiency due to the accumulation of coolant in the flow path can be suppressed. Thus, with the above configuration, the power conversion device can be miniaturized, taking into account the heat dissipation properties of the heat-generating components.

[0061] For example, in the heat dissipation structure 3 according to the embodiment, a resin fixing plate 51 made of an insulating resin material can be used as a fixing plate for fixing the heat-generating component, thereby eliminating the need for insulation between the MOSFET 23 and the resin fixing plate 51.

[0062] Therefore, the heat dissipation structure 3 according to the embodiment can eliminate the need for package insulation for the MOSFET 23. This allows the use of a general-purpose MOSFET 23, thereby reducing costs. Furthermore, the configuration that eliminates the need for package insulation can reduce the size of the MOSFET 23 by the amount of insulating resin that forms the package insulation, thereby improving the mounting density and freedom of arrangement and enabling the miniaturization of the power conversion device 1.

[0063] In the heat dissipation structure 3 according to this embodiment, heat from each of the plurality of MOSFETs 23 is guided to the horizontal plane by the plurality of heat conduction sheets 71 that are independent of one another. Therefore, insulation between the MOSFETs 23 is ensured without providing an insulating layer on the heat dissipation surface 235 of the MOSFETs 23, and heat from the heat dissipation surface 235 can be guided to the horizontal plane with low thermal resistance.

[0064] Furthermore, with a configuration that does not require package insulation or an insulating layer for the heat dissipation surface 235, the heat dissipation surface 235 is thermally connected to the heat conduction sheet 71 without the intervention of insulating resin, thereby reducing the thermal resistance associated with heat dissipation from the heat dissipation surface 235. In other words, heat can be drawn with low thermal resistance from the heat dissipation surface 235 (vertical portion) to the second portion 713 (horizontal portion) of the heat conduction sheet 71 that is parallel to the cooling surface of the metal casing 41.

[0065] Furthermore, with a configuration that does not require package insulation or an insulating layer on the heat dissipation surface 235, the MOSFET 23 can be attached to the resin fixing plate 51 by screw fixing using pre-installed standard fixing holes and metal screws. This simplifies the fixing configuration, making manufacturing easier. Furthermore, unlike fixing with an adhesive, this eliminates the need for a process of pressing the MOSFET 23 against the fixing portion (groove portion 511) for fixing, thereby reducing the pressure (load) on the MOSFET 23 associated with fixing.

[0066] The fixing portion of resin fixing plate 51 to which MOSFET 23 is attached is recessed groove 511. This facilitates attachment of MOSFET 23 at a predetermined position in a predetermined posture, improving manufacturability, and also ensures a creepage distance (insulation distance) because a portion of insulating resin fixing plate 51 is interposed between adjacent MOSFETs 23.

[0067] (Second embodiment) In the heat dissipation structure 3 according to the above-described embodiment, the resin fixing plate 51 does not necessarily have to be provided with the groove portion 511.

[0068] 5 is a cross-sectional view showing another example of the configuration of the heat dissipation structure 3 included in the power conversion device 1 according to this embodiment. FIG. 5 corresponds to a cross section of the IV-IV plane (YZ plane) of FIG. 2 as viewed from the lower side (-X side) of the paper. As shown in FIG. 5, in the heat dissipation structure 3 according to this embodiment, each of the multiple MOSFETs 23 may be disposed on a flat portion on the main surface (ZX plane) of the resin fixing plate 51. In other words, the fixing portion of the resin fixing plate 51 may be at a predetermined position on the flat portion on the main surface.

[0069] According to this configuration, the side surface (YZ plane) of the body 231 of each of the multiple MOSFETs 23 is exposed and not covered by the resin fixing plate 51. This increases the amount of heat transferred by heat conduction or radiation from the MOSFETs 23 to the surrounding air or to an electrically insulating filler or potting material, thereby improving heat dissipation efficiency.

[0070] (Third embodiment) This embodiment describes another configuration example of the heat transport path between the heat dissipation surface 235 of the MOSFET 23 and the cooling surface of the metal casing 41. This embodiment mainly describes the differences from the heat dissipation structure 3 according to the second embodiment, but can be combined with the heat dissipation structure 3 according to the first embodiment.

[0071] FIG. 6 is a cross-sectional view showing another example of the configuration of the heat dissipation structure 3 included in the power converter 1 according to this embodiment. FIG. 6 corresponds to a cross section of the IV-IV plane (YZ plane) of FIG. 2 as viewed from the lower side (-X side) of the paper. As shown in FIG. 6, in the heat dissipation structure 3 according to this embodiment, an insulating heat dissipation adhesive sheet 79 is provided between the second portion 713 of the thermally conductive sheet 71 and the cooling surface of the metal casing 41. That is, the heat dissipation structure 3 according to this embodiment has a configuration in which the adhesive 73, the metal plate with insulating layer 75, and the thermal grease 77 in the heat dissipation structure 3 according to the second embodiment are replaced with the insulating heat dissipation adhesive sheet 79. Here, the insulating heat dissipation adhesive sheet 79 according to this embodiment is an example of a first adhesive sheet.

[0072] The insulating heat-dissipating adhesive sheet 79 is a sheet-shaped member made of a material having electrical insulation, heat dissipation (thermal conductivity), and adhesiveness (adhesion). As shown in FIG. 6 , the upper surface (+Z side surface) of the insulating heat-dissipating adhesive sheet 79 faces the lower surfaces (-Z side surfaces) of the second portions 713 of the thermally conductive sheets 71. That is, the insulating heat-dissipating adhesive sheet 79 is disposed between the second portions 713 of the thermally conductive sheets 71 and the cooling surface of the metal housing 41, spanning the second portions 713. The second portions 713 of the thermally conductive sheets 71 are adhered to the upper surface of the insulating heat-dissipating adhesive sheet 79, respectively, for thermal connection. The lower surface (-Z side surface) of the insulating heat-dissipating adhesive sheet 79 faces the cooling surface of the metal housing 41. The lower surface of the insulating heat-dissipating adhesive sheet 79 is adhered to the cooling surface of the metal housing 41 for thermal connection. In other words, the insulating heat dissipating adhesive sheet 79 transports heat from the multiple MOSFETs 23 thermally connected to its upper surface via the multiple heat conductive sheets 71 to the cooling surface of the metal casing 41 on its lower surface.

[0073] According to this configuration, the heat transport path between the heat conduction sheet 71 and the cooling surface of the metal housing 41 can be configured more simply, thereby reducing the thermal resistance and improving manufacturability.

[0074] (Fourth embodiment) The housing of the power conversion device 1 is not limited to metal such as die-cast, and may be made of non-metal. In this embodiment, differences from the heat dissipation structure 3 according to the second embodiment will be mainly described, but the present embodiment can be combined with the heat dissipation structure 3 according to the first embodiment.

[0075] 7 is a cross-sectional view showing another example of the configuration of the heat dissipation structure 3 of the power conversion device 1 according to this embodiment. FIG. 7 corresponds to a cross section of the IV-IV plane (YZ plane) of FIG. 2 as viewed from the lower side (-X side) of the paper. As shown in FIG. 7, the heat dissipation structure 3 according to this embodiment has a resin housing 42. That is, the heat dissipation structure 3 according to this embodiment has a configuration in which the metal housing 41 in the heat dissipation structure 3 according to the second embodiment is replaced with the resin housing 42.

[0076] The resin housing 42 is similar to the metal housing 41 according to the second embodiment, except that it is made of a resin material having insulating properties and heat dissipation properties (thermal conductivity). The resin housing 42 may be formed integrally with the resin fixing plate 51. The resin housing 42 and the resin fixing plate 51 are formed of, for example, the same resin material, but may also be formed of different resin materials.

[0077] Because the resin housing 42 has insulating properties, a separate insulating structure is not required between the cooling surface of the resin housing 42 and the second portion 713 of the thermally conductive sheet 71. As an example, as shown in Fig. 7, the heat dissipation structure 3 according to this embodiment has a configuration in which the adhesive 73, the metal plate 75 with an insulating layer, and the thermal grease 77 in the heat dissipation structure 3 according to the second embodiment are replaced with a heat dissipation adhesive sheet 81. Here, the heat dissipation adhesive sheet 81 according to this embodiment is an example of a second adhesive sheet.

[0078] The heat-dissipating adhesive sheet 81 is a sheet-shaped member made of a material having heat dissipation (thermal conductivity) and adhesiveness (adhesion). Unlike the insulating heat-dissipating adhesive sheet 79 according to the third embodiment, the heat-dissipating adhesive sheet 81 does not need to be electrically insulating. As shown in FIG. 7 , the upper surface (+Z side surface) of the heat-dissipating adhesive sheet 81 is thermally connected to each of the second portions 713 of the thermally conductive sheets 71. That is, the heat-dissipating adhesive sheet 81 is disposed between the second portions 713 of the thermally conductive sheets 71 and the cooling surface of the metal housing 41, spanning the second portions 713. The lower surface (-Z side surface) of the insulating heat-dissipating adhesive sheet 79 is thermally connected to the cooling surface of the plastic housing 42. That is, the insulating heat-dissipating adhesive sheet 79 transports heat from the MOSFETs 23, which are thermally connected to its upper surface via the thermally conductive sheets 71, to the cooling surface of the plastic housing 42 on its lower surface.

[0079] This configuration allows for a simpler configuration of the heat transport path between the thermally conductive sheet 71 and the cooling surface of the resin housing 42, thereby improving manufacturability. Furthermore, by forming the housing from resin, the weight of the power conversion device 1 can be reduced.

[0080] (Fifth embodiment) This embodiment describes another configuration example of the heat transport path between the heat dissipation surface 235 of the MOSFET 23 and the cooling surface of the metal casing 41. This embodiment mainly describes the differences from the heat dissipation structure 3 according to the second embodiment, but can be combined with the heat dissipation structure 3 according to each of the above-described embodiments.

[0081] 8 is a cross-sectional view showing another example of the configuration of the heat dissipation structure 3 included in the power conversion device 1 according to this embodiment. Fig. 8 corresponds to a cross section of the IV-IV plane (YZ plane) of Fig. 2 as viewed from the lower side (-X side) of the paper. As shown in Fig. 8, in the heat dissipation structure 3 according to this embodiment, the adhesive 73, the metal plate 75 with an insulating layer, and the thermal grease 77 are provided on the opposite side (for example, the -Y side) from the MOSFET 23 across the main surface (ZX plane) of the resin fixing plate 51.

[0082] 8, in the heat dissipation structure 3 according to this embodiment, the thermally conductive sheet 71 extends in a direction (+Y direction) from one main surface (first main surface) of the resin fixing plate 51 toward the other main surface (second main surface) of the resin fixing plate 51. As an example, the thermally conductive sheet 71 passes through the hole 513 of the resin fixing plate 51.

[0083] According to this configuration, the surface (+Y side surface) of the first portion 711 of the thermally conductive sheet 71 that contacts the heat dissipation surface 235 of the MOSFET 23 is flush with the surface (-Z side surface) of the second portion 713 that is bonded to the metal plate with insulation layer 75 via the adhesive 73. That is, the thermally conductive sheet 71 can transport heat from the heat dissipation surface 235 of the MOSFET 23 to the metal plate with insulation layer 75 that is parallel to the cooling surface of the metal casing 41 within the same plane. Therefore, the heat transport path between the heat dissipation surface 235 of the MOSFET 23 and the cooling surface of the metal casing 41 does not include a path in the thickness direction of the thermally conductive sheet 71, but includes only a path in the planar direction. Here, when the thermally conductive sheet 71 is formed using a carbon-based material such as graphite, its thermal conductivity in the planar direction is greater than its thermal conductivity in the thickness direction. Therefore, with the above configuration, heat from the heat dissipation surface 235 of the MOSFET 23 can be drawn to the horizontal surface with lower thermal resistance, thereby further improving heat dissipation.

[0084] (Sixth embodiment) This embodiment describes another configuration example of the heat transport path between the heat dissipation surface 235 of the MOSFET 23 and the cooling surface of the metal casing 41. This embodiment mainly describes the differences from the heat dissipation structure 3 according to the second embodiment, but can be combined with the heat dissipation structure 3 according to each of the above-described embodiments.

[0085] FIG. 9 is a cross-sectional view showing another example of the configuration of the heat dissipation structure 3 included in the power converter 1 according to this embodiment. FIG. 9 corresponds to a cross section of the IV-IV plane (YZ plane) of FIG. 2 as viewed from the lower side (-X side) of the paper. As shown in FIG. 9, in the heat dissipation structure 3 according to this embodiment, an insulating layer-equipped metal plate 75 and thermal grease 77 are provided between the second portion 713 of the thermal conduction sheet 71 and the cooling surface of the metal casing 41. Furthermore, an insulating layer-equipped press plate 83 is provided on the opposite side (+Z side) of the second portion 713 of the thermal conduction sheet 71 from the cooling surface of the metal casing 41. In other words, the heat dissipation structure 3 according to this embodiment has a configuration in which the adhesive 73 in the heat dissipation structure 3 according to the second embodiment is replaced with the insulating layer-equipped press plate 83. Here, the insulating layer-equipped press plate 83 according to this embodiment is an example of a second plate-shaped member.

[0086] The insulating layer-attached press plate 83 is a member formed in a flat plate shape. The insulating layer-attached press plate 83 is made of a metal material having thermal conductivity, such as aluminum. Note that the insulating layer-attached press plate 83 may be made of a non-metallic material as long as it can press the insulating layer-attached metal plate 75 arranged on its lower surface side (-Z side) against the cooling surface of the metal casing 41. Preferably, the insulating layer-attached press plate 83 is made of a metal material having thermal conductivity and functions as a heat diffusion plate (heat capacity).

[0087] 9, the lower surface (the surface on the -Z side) of the insulating layer-attached press plate 83 is disposed opposite each of the second portions 713 of each of the thermally conductive sheets 71. In other words, the insulating layer-attached press plate 83 extends in the direction (X direction) along the row of the MOSFETs 23 fixed to the resin fixing plate 51, and is provided across the second portions 713 of each of the thermally conductive sheets 71. In addition, the lower surface of the insulating layer-attached press plate 83 is thermally connected to each of the second portions 713 of each of the thermally conductive sheets 71.

[0088] The insulating layer-equipped press plate 83 is configured to press the insulating layer-equipped metal plate 75 against the cooling surface side (thermal conduction sheet 71 side) of the metal casing 41. As an example, the insulating layer-equipped press plate 83 presses the insulating layer-equipped metal plate 75 against the cooling surface side of the metal casing 41 by its own weight. The insulating layer-equipped press plate 83 may be fixed to the metal casing 41 or the resin fixing plate 51 by a fixing member (not shown) such as a screw, and the fixing portion may be used as a fulcrum to press the insulating layer-equipped metal plate 75 against the cooling surface side of the metal casing 41. The fixing member may also have an elastic member that urges the insulating layer-equipped press plate 83 against the cooling surface side of the metal casing 41.

[0089] An insulating layer having electrical insulation properties is formed on at least the lower surface (-Z side surface) of the outer surface of the insulating layer-attached press plate 83. In other words, at least the lower surface of the insulating layer-attached press plate 83 is subjected to an insulating treatment to form an insulating layer.

[0090] According to this configuration, the upper surface (surface on the +Z side) of the second portion 713 of the thermally conductive sheet 71 can also be efficiently cooled, thereby further improving the heat dissipation of the heat-generating components.

[0091] (Seventh embodiment) This embodiment describes another configuration example of the heat transport path between the heat dissipation surface 235 of the MOSFET 23 and the cooling surface of the metal casing 41. This embodiment mainly describes the differences from the heat dissipation structure 3 according to the sixth embodiment, but can be combined with the heat dissipation structure 3 according to each of the above-described embodiments.

[0092] FIG. 10 is a cross-sectional view showing another example of the configuration of the heat dissipation structure 3 included in the power converter 1 according to the embodiment. FIG. 10 corresponds to a cross section of the IV-IV plane (YZ plane) of FIG. 2 as viewed from the lower side (-X side) of the drawing. As shown in FIG. 10, in the heat dissipation structure 3 according to the present embodiment, an insulating layer-equipped metal plate 75 and thermal grease 77 are provided between the second portion 713 of the thermal conduction sheet 71 and the cooling surface of the metal casing 41. Furthermore, an insulating layer-equipped heat sink 85 is provided on the opposite side (+Z side) of the second portion 713 of the thermal conduction sheet 71 from the cooling surface of the metal casing 41. In other words, the heat dissipation structure 3 according to the present embodiment has a configuration in which the insulating layer-equipped press plate 83 in the heat dissipation structure 3 according to the sixth embodiment is replaced with the insulating layer-equipped heat sink 85. Here, the insulating layer-equipped heat sink 85 according to the embodiment is an example of a second plate-shaped member having an extended heat transfer surface.

[0093] The heat sink 85 with an insulating layer has a structure in which an extended heat transfer surface such as a fin array is formed on the main surface on the upper surface side (+Z side) of the pressing plate 83 with an insulating layer. The shape of the extended heat transfer surface is arbitrary and can be selected appropriately.

[0094] According to this configuration, the upper surface (the surface on the +Z side) of the second portion 713 of the thermally conductive sheet 71 can be cooled more efficiently, thereby further improving the heat dissipation of the heat-generating components.

[0095] According to at least one of the embodiments described above, it is possible to reduce the size of the power converter by taking into consideration the heat dissipation properties of the heat-generating components.

[0096] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents.

[0097] (Addendum) The above description of the embodiments discloses the following techniques. (1) a housing having a flow path for a cooling liquid formed therein, the flow path running along the cooling surface; a heat dissipation structure disposed on the cooling surface of the housing, The heat dissipation structure includes a plurality of power semiconductors, each of whose heat dissipation surfaces is not electrically insulated, a resin fixing plate formed in a flat plate shape using an electrically insulating resin material, and having a first main surface on which each of the plurality of power semiconductors is fixed, and a plurality of thermally conductive sheets, each of which has thermal conductivity; the plurality of thermally conductive sheets have first portions disposed between the plurality of heat dissipation surfaces of the plurality of power semiconductors and the resin fixing plate, when the heat dissipation structure is disposed on the cooling surface of the housing, the first main surface of the resin fixing plate extends in a direction away from the cooling surface of the housing, the first portion of each of the plurality of thermally conductive sheets is thermally connected to the corresponding heat dissipation surface, and extends from the connection portion with the heat dissipation surface along the first main surface of the resin fixing plate in a direction toward the cooling surface of the housing; the second portions of the plurality of thermally conductive sheets extend from the cooling surface side of the first portions along the cooling surface of the housing in a direction away from the resin fixing plate, and are thermally connected to the cooling surface; Power conversion device. (2) a first plate-like member formed in a flat plate shape using a thermally conductive material, and disposed between the second portions of the thermally conductive sheets and the cooling surface of the housing, spanning the second portions, and having an insulating layer having electrical insulation formed on at least a main surface facing the second portions; the first plate-shaped member is thermally connected to each of the second portions of the thermally conductive sheets via a thermally conductive adhesive, and is thermally connected to the cooling surface of the housing via a thermally conductive thermal grease; The power conversion device according to (1) above. (3) The heat conductive sheet further includes a first adhesive sheet formed into a sheet shape using a material having thermal conductivity, electrical insulation, and adhesiveness, the first adhesive sheet being disposed between the second portions of the heat conductive sheets and the cooling surface of the housing and across the second portions. The power conversion device according to (1) or (2) above. (4) the resin fixing plate is provided with a hole portion penetrating between the first main surface and a second main surface opposite to the first main surface, the second portions of each of the plurality of thermally conductive sheets pass through the holes and extend in a direction from the first main surface to the second main surface; The power conversion device according to any one of (1) to (3) above. (5) a first plate-like member formed in a flat plate shape using a thermally conductive material, and disposed between the second portions of the thermally conductive sheets and the cooling surface of the housing, spanning the second portions, and having an insulating layer having electrical insulation formed on at least a main surface facing the second portions; a second plate-like member formed in a flat plate shape using a thermally conductive material, disposed across the second portions of the thermally conductive sheets on the opposite side of the cooling surface of the housing from the second portions, and having an insulating layer having electrical insulation formed on at least a main surface facing the second portions, the first plate-shaped member is thermally connected to the cooling surface of the housing via thermally conductive thermal grease; the second plate-shaped member presses the first plate-shaped member against the cooling surface of the housing; The power conversion device according to any one of (1) to (4) above. (6) the second plate-shaped member has an extended heat transfer surface formed on a main surface of the plurality of heat conduction sheets opposite to the plurality of second portions; The power conversion device according to (5) above. (7) a second adhesive sheet formed in a sheet shape using a material having thermal conductivity and adhesiveness, the second adhesive sheet being disposed between the second portions of the thermally conductive sheets and the cooling surface of the housing, across the second portions; The housing is formed of an electrically insulating resin material. The power conversion device according to (1), (2), or (4). (8) The housing is formed of a metal material. The power conversion device according to any one of (1) to (6) above. (9) the resin fixing plate has a plurality of grooves formed in the first main surface, each of which has a concave shape extending in a direction away from the cooling surface of the housing; The plurality of power semiconductors are disposed in the plurality of groove portions. The power conversion device according to any one of (1) to (8) above. (10) the second portion of each of the plurality of thermally conductive sheets is wider than the heat dissipation surface of each of the plurality of power semiconductors; The power conversion device according to any one of (1) to (9) above. (11) The power conversion device according to any one of (1) to (10) above, which converts AC power from an external AC power source into DC power; a battery that is charged using the DC power converted by the power conversion device. vehicle. (12) A heat dissipation structure disposed on a cooling surface of a housing having a flow path for a cooling liquid formed therein, the flow path running along the cooling surface, A plurality of power semiconductors whose heat dissipation surfaces are not electrically insulated, a resin fixing plate formed in a flat plate shape using an electrically insulating resin material, and having each of the plurality of power semiconductors fixed to a first main surface; a plurality of thermally conductive sheets each having thermal conductivity; the plurality of thermally conductive sheets have first portions disposed between the plurality of heat dissipation surfaces of the plurality of power semiconductors and the resin fixing plate, when the heat dissipation structure is disposed on the cooling surface of the housing, the first main surface of the resin fixing plate extends in a direction away from the cooling surface of the housing, the first portion of each of the plurality of thermally conductive sheets is thermally connected to the corresponding heat dissipation surface, and extends from the connection portion with the heat dissipation surface along the first main surface of the resin fixing plate in a direction toward the cooling surface of the housing; the second portions of the plurality of thermally conductive sheets extend from the cooling surface side of the first portions along the cooling surface of the housing in a direction away from the resin fixing plate, and are thermally connected to the cooling surface; Heat dissipation structure. [Explanation of symbols]

[0098] 1 Power conversion device 2 Circuit configuration 21a, 21b Power lines 23, 23a to 23d MOSFETs 231 Main Unit 233 leads 235 Heat radiation surface 3 Heat dissipation structure 41 Metal Case 42 Resin housing 43 Flow path 51 Resin fixing plate 511 Groove 513 Hole 6 Fixing member 71 Thermal Conduction Sheet 711 Part 1 713 Part 2 73 Adhesive 75 Metal plate with insulating layer 77 Thermal grease 79 Insulating and heat dissipating adhesive sheet 81 Heat dissipation adhesive sheet 83 Press plate with insulating layer 85 Heat sink with insulating layer 9 Load circuit R1~R4 areas

Claims

1. a housing having a flow path for a cooling liquid formed therein, the flow path running along the cooling surface; a heat dissipation structure disposed on the cooling surface of the housing, the heat dissipation structure includes a plurality of power semiconductors, each of whose heat dissipation surfaces is not electrically insulated; a resin fixing plate formed in a flat plate shape using an electrically insulating resin material, and having a first main surface on which each of the plurality of power semiconductors is fixed; and a plurality of thermally conductive sheets, each of which has thermal conductivity; the plurality of thermally conductive sheets each have a first portion disposed between the plurality of heat dissipation surfaces of the plurality of power semiconductors and the resin fixing plate; when the heat dissipation structure is disposed on the cooling surface of the housing, the first main surface of the resin fixing plate extends in a direction away from the cooling surface of the housing, the first portion of each of the plurality of thermally conductive sheets is thermally connected to the corresponding heat dissipation surface, and extends from the connection portion with the heat dissipation surface along the first main surface of the resin fixing plate in a direction toward the cooling surface of the housing; the second portions of the plurality of thermally conductive sheets extend from the cooling surface side of the first portions along the cooling surface of the housing in a direction away from the resin fixing plate, and are thermally connected to the cooling surface; Power conversion device.

2. a first plate-like member formed in a flat plate shape using a thermally conductive material, and disposed between the second portions of the thermally conductive sheets and the cooling surface of the housing, spanning the second portions, and having an insulating layer having electrical insulation formed on at least a main surface facing the second portions; the first plate-shaped member is thermally connected to each of the second portions of the thermally conductive sheets via a thermally conductive adhesive, and is thermally connected to the cooling surface of the housing via a thermally conductive thermal grease; The power conversion device according to claim 1 .

3. The heat conductive sheet further includes a first adhesive sheet formed in a sheet shape using a material having thermal conductivity, electrical insulation, and adhesiveness, the first adhesive sheet being disposed between the second portions of the heat conductive sheets and the cooling surface of the housing and across the second portions. The power conversion device according to claim 1 .

4. the resin fixing plate is provided with a hole portion penetrating between the first main surface and a second main surface opposite to the first main surface, the second portions of the thermally conductive sheets pass through the holes and extend in a direction from the first main surface to the second main surface; The power conversion device according to claim 1 .

5. a first plate-like member formed in a flat plate shape using a thermally conductive material, and disposed between the second portions of the thermally conductive sheets and the cooling surface of the housing, spanning the second portions, and having an insulating layer having electrical insulation formed on at least a main surface facing the second portions; a second plate-like member formed in a flat plate shape using a thermally conductive material, disposed across the second portions of the thermally conductive sheets on the opposite side of the cooling surface of the housing from the second portions, and having an insulating layer having electrical insulation formed on at least a main surface facing the second portions, the first plate-shaped member is thermally connected to the cooling surface of the housing via thermally conductive thermal grease; the second plate-shaped member presses the first plate-shaped member against the cooling surface of the housing; The power conversion device according to claim 1 .

6. the second plate-shaped member has an extended heat transfer surface formed on a main surface of the second plate-shaped member opposite to the second portions of the thermally conductive sheets; The power conversion device according to claim 5 .

7. a second adhesive sheet formed in a sheet shape using a thermally conductive and adhesive material, the second adhesive sheet being disposed between the second portions of the thermally conductive sheets and the cooling surface of the housing, across the second portions; The housing is formed of an electrically insulating resin material. The power conversion device according to claim 1 .

8. The housing is formed of a metal material. The power conversion device according to claim 1 .

9. the resin fixing plate has a plurality of grooves formed in the first main surface, each of which has a concave shape extending in a direction away from the cooling surface of the housing; The plurality of power semiconductors are disposed in the plurality of groove portions. The power conversion device according to any one of claims 1 to 8.

10. the second portions of the thermally conductive sheets are wider than the heat dissipation surfaces of the power semiconductors; The power conversion device according to any one of claims 1 to 8.

Images