Power conversion device

Abstract

To provide a power conversion device which can be reduced in size while ensuring heat dissipation.SOLUTION: The power converter includes a cooler 30, a filter module 80, and a heat conduction member 90. The filter module 80 is a bus bar module that includes the bus bars 81 including the facing portions 813 in which the plate surfaces face each other, and the holding member 82 that holds the bus bars 81, and is disposed on the cooler 30. The bus bar 81 is arranged such that the arrangement direction of the cooler 30 and the filter module 80 and the facing direction of the facing portion 813 intersect with each other. The holding member 82 has a recessed portion 821 that opens in the 82a of one surface that is a surface on the coolers 30 side and is provided between the facing portions 813 so as to overlap with the facing portions 813 in a plan view in the facing direction. The heat conductive member 90 is disposed in the recessed portion 821.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The disclosure herein relates to power conversion devices. [Background technology]

[0002] Patent Document 1 discloses a power conversion device. The contents of the prior art document are incorporated by reference as explanations of the technical elements in this specification. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-107381 Summary of the Invention [Problem to be solved by the invention]

[0004] A noise filter is disposed on the bottom wall of the housing. A cooling passage is provided in the bottom wall, and the bottom wall functions as a cooler. The noise filter has external bus bars, a P bus bar and an N bus bar. The external bus bars face the outer bottom surface of the bottom wall in the Z direction. To dissipate heat from the external bus bars, it is necessary to increase the facing area between the external bus bars and the cooler. Further improvements are required in power conversion devices in the above respects and in other respects not mentioned.

[0005] One object of the present disclosure is to provide a power conversion device that can be made smaller in size while ensuring heat dissipation. [Means for solving the problem]

[0006] A power conversion device according to one aspect of the disclosure includes: a cooler (30); a bus bar module (80) including bus bars (81) each including an opposing portion (813) where the plate surfaces face each other, and a holding member (82) for holding the bus bars, the bus bar module (80) being disposed on a cooler; a heat conduction member (90) for transferring heat from the bus bar to the cooler; Equipped with the busbars are arranged so that the arrangement direction of the cooler and the busbar module intersects with the opposing direction of the opposing portions; the holding member has an opening on one surface (82a) that is a surface on the cooler side, and a recess (821) provided between the opposing portions so as to overlap with the opposing portions in a plan view in the opposing direction; The heat conducting member is disposed in the recess.

[0007] According to the disclosed power conversion device, the busbars are provided with opposing portions where the plate surfaces face each other, and the busbars are arranged so that the opposing direction of the opposing portions intersects with the arrangement direction of the cooler and busbar modules. This allows the busbar modules, and therefore the power conversion device, to be downsized in the opposing direction. Furthermore, recesses are provided in the holding members between the opposing portions, and thermally conductive members are disposed in the recesses. This allows heat generated by the busbars to be effectively dissipated via the thermally conductive members. As a result, a power conversion device can be provided that can be downsized while maintaining heat dissipation performance.

[0008] The various aspects disclosed in this specification employ different technical means to achieve their respective objectives. The reference numerals in parentheses in the claims are intended to exemplarily indicate the corresponding parts of the embodiments described below, and are not intended to limit the technical scope. The objectives, features, and advantages disclosed in this specification will become more apparent by reference to the following detailed description and the accompanying drawings. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 illustrates a power conversion circuit and a drive system. [Figure 2] 1 is a plan view showing an example of a power conversion device according to a first embodiment. [Figure 3] FIG. 2 is a plan view of the power conversion device as seen from the filter module side. [Figure 4] FIG. 10 is a plan view showing a filter module without a holding member. [Figure 5] FIG. 3 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 6 is an enlarged view of region VI in FIG. 5. [Figure 7] FIG. [Figure 8] FIG. [Figure 9] FIG. [Figure 10] FIG. 10 is an enlarged view of the periphery of an opposing portion in a power conversion device according to a second embodiment. [Figure 11] FIG. [Figure 12] FIG. 11 is an enlarged view of the periphery of an opposing portion in a power conversion device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, several embodiments will be described with reference to the drawings. Note that in each embodiment, corresponding components are designated by the same reference numerals, and redundant description may be omitted. When only a portion of the configuration is described in each embodiment, the configuration of another embodiment previously described may be applied to the remaining portion of the configuration. Furthermore, in addition to the combinations of configurations explicitly stated in the description of each embodiment, configurations of several embodiments may be partially combined together even if not explicitly stated, provided that there is no particular problem with the combination.

[0011] (First embodiment) The capacitor module of this embodiment is applied to, for example, a mobile body that uses a rotating electric machine as a drive source. Examples of the mobile body include electric vehicles such as battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs), electric flying bodies such as drones and electric vertical take-off and landing aircraft (eVTOLs), ships, construction machinery, and agricultural machinery. BEV is an abbreviation for Battery Electric Vehicle. HEV is an abbreviation for Hybrid Electric Vehicle. eVTOL is an abbreviation for electronic Vertical Take-Off and Landing aircraft. An example of application to a vehicle will be described below.

[0012] <Vehicle drive system> 1 shows an example of a vehicle drive system. The drive system 1 includes a DC power supply 2, a motor generator 3, and a power conversion circuit 4.

[0013] The DC power supply 2 is a DC voltage source made up of a rechargeable secondary battery. The secondary battery may be, for example, a lithium-ion battery or a nickel-metal hydride battery. The DC power supply 2 may convert AC to DC and output it. The motor generator 3 is a three-phase AC rotating electric machine. The motor generator 3 functions as a drive source for the vehicle, that is, an electric motor. The motor generator 3 functions as a generator during regeneration. The power conversion circuit 4 converts power between the DC power supply 2 and the motor generator 3.

[0014] <Power conversion circuit> 1 shows an example of a power conversion circuit 4. The power conversion circuit 4 shown in FIG.

[0015] The smoothing capacitor 5 mainly smoothes the DC voltage supplied from the DC power supply 2. The smoothing capacitor 5 is connected to a P line 7, which is a power supply line on the high potential side, and an N line 8, which is a power supply line on the low potential side. The P line 7 is connected to the positive electrode of the DC power supply 2, and the N line 8 is connected to the negative electrode of the DC power supply 2. The positive electrode of the smoothing capacitor 5 is connected to the P line 7 between the DC power supply 2 and the inverter 6. The negative electrode of the smoothing capacitor 5 is connected to the N line 8 between the DC power supply 2 and the inverter 6. The smoothing capacitor 5 is connected in parallel to the DC power supply 2.

[0016] The inverter 6 is a DC-AC conversion circuit. In accordance with switching control by the control circuit, the inverter 6 converts a DC voltage into a three-phase AC voltage and outputs it to the motor generator 3. This drives the motor generator 3 to generate a predetermined torque. During regenerative braking of the vehicle, the inverter 6 converts the three-phase AC voltage generated by the motor generator 3 in response to rotational force from the wheels into a DC voltage in accordance with switching control by the control circuit and outputs it to the P line 7. In this way, the inverter 6 performs bidirectional power conversion between the DC power supply 2 and the motor generator 3.

[0017] The inverter 6 is configured to include upper and lower arm circuits 9 for three phases. The upper and lower arm circuits 9 are sometimes referred to as legs. Each upper and lower arm circuit 9 has an upper arm 9H and a lower arm 9L. The upper arm 9H and the lower arm 9L are connected in series between the P line 7 and the N line 8, with the upper arm 9H on the P line 7 side. Hereinafter, the upper arm 9H and the lower arm 9L may be simply referred to as arms 9H and 9L.

[0018] The connection point between the upper arm 9H and the lower arm 9L, i.e., the midpoint of the upper and lower arm circuits 9, is connected to the corresponding phase winding 3a of the motor generator 3 via an output line 10. Of the upper and lower arm circuits 9, the U-phase upper and lower arm circuit 9U is connected to the U-phase winding 3a via the output line 10. The V-phase upper and lower arm circuit 9V is connected to the V-phase winding 3a via the output line 10. The W-phase upper and lower arm circuit 9W is connected to the W-phase winding 3a via the output line 10.

[0019] The number of switching elements constituting each arm 9H, 9L is not particularly limited. It may be one or more. In the illustrated upper arm 9H, three switching elements are connected in parallel. In the lower arm 9L, three switching elements are connected in parallel. In other words, each of the six arms 9H, 9L of the three-phase upper and lower arm circuit 9 is composed of three switching elements connected in parallel to each other.

[0020] The illustrated switching element is an n-channel MOSFET 11. MOSFET is an abbreviation for Metal Oxide Semiconductor Field Effect Transistor. The three MOSFETs 11 on the high side connected in parallel are turned on and off at the same timing by a common gate drive signal (drive voltage). The three MOSFETs 11 on the low side connected in parallel are turned on and off at the same timing by a common gate drive signal (drive voltage).

[0021] A freewheeling diode 12 is connected in anti-parallel to each MOSFET 11. The diode 12 may be a parasitic diode (body diode) or an external diode. In the upper arm 9H, the drain of the MOSFET 11 is connected to the P line 7. In the lower arm 9L, the source of the MOSFET 11 is connected to the N line 8. The source of the MOSFET 11 in the upper arm 9H and the drain of the MOSFET 11 in the lower arm 9L are connected to each other. The anode of the diode 12 is connected to the source of the corresponding MOSFET 11, and the cathode is connected to the drain.

[0022] The switching element is not limited to the MOSFET 11. For example, an IGBT may be used. IGBT is an abbreviation for Insulated Gate Bipolar Transistor. In the case of an IGBT, a freewheeling diode is also connected in anti-parallel.

[0023] As illustrated in FIG. 1, the power conversion circuit 4 may include a drive control unit (DCU) 13. The drive control unit 13 may be configured to include, for example, a processor, a memory, and a storage. The processor executes various processes by accessing the memory. The memory is a rewritable volatile storage medium. The memory is, for example, RAM. RAM is an abbreviation for Random Access Memory. The storage is a rewritable nonvolatile memory. The storage may be realized by at least one type of non-transitory tangible storage medium, such as a semiconductor memory, a magnetic medium, or an optical medium. The storage may include multiple types of storage media, such as a ROM and a flash memory. ROM is an abbreviation for Read Only Memory.

[0024] The storage stores a program including instructions for the processor to execute a predetermined process. The processor executes a plurality of instructions in the program to establish a plurality of functional units for executing the predetermined process. The process executed by the drive control unit 13 may be realized by software processing in which the processor executes the program, or may be realized by hardware processing using a dedicated electronic circuit. It may also be realized by a combination of software processing and hardware processing.

[0025] The drive control unit 13 has, for example, a drive circuit (DC) 14 and a control circuit (CC) 15. The drive circuit 14 supplies a drive voltage to the gate of the MOSFET 11 of the corresponding arm based on a drive command from the control circuit 15. The drive circuit 14 drives the corresponding MOSFET 11, i.e., turns it on and off, by applying the drive voltage. The drive circuit 14 is sometimes referred to as a driver.

[0026] The control circuit 15 generates a drive command for operating the MOSFET 11 and outputs it to the drive circuit 14. The control circuit 15 generates the drive command based on, for example, a torque request input from a higher-level ECU (not shown) and signals detected by various sensors. The control circuit 15 controls the operation of the drive circuit 14. ECU is an abbreviation for Electronic Control Unit.

[0027] The various sensors are, for example, a current sensor 16, a rotation angle sensor, and a voltage sensor. The current sensor 16 detects the phase current flowing through the winding 3a of each phase. The rotation angle sensor detects the rotation angle of the rotor of the motor generator 3. The voltage sensor detects the voltage across the smoothing capacitor 5. The control circuit 15 outputs, for example, a PWM signal as a drive command. PWM is an abbreviation for Pulse Width Modulation. The power conversion circuit 4 may include at least one of the above sensors. The illustrated power conversion circuit 4 includes a current sensor 16.

[0028] As illustrated in FIG. 1, the power conversion circuit 4 may include a filter circuit 17. The filter circuit 17 is a circuit for reducing noise such as electromagnetic noise. The filter circuit 17 is sometimes called an EMI filter. EMI is an abbreviation for Electromagnetic Interference. The filter circuit 17 is connected in parallel to the smoothing capacitor 5 and the inverter 6. The filter circuit 17 is provided between the DC power supply 2 and the smoothing capacitor 5. The filter circuit 17 includes a coil, a capacitor, and the like.

[0029] The illustrated filter circuit 17 includes a choke coil 18 and a Y capacitor 19. The choke coil 18 may also be referred to as a common mode coil, a filter core, an EMI core, etc. The choke coil 18 and the Y capacitor 19 reduce common mode noise. The filter circuit 17 may also include an X capacitor or a normal mode coil to reduce normal mode noise.

[0030] The power conversion circuit 4 may include a converter. The converter is a DC-DC conversion circuit configured to be able to convert a DC voltage into a DC voltage of a different value, for example. The converter is provided between the DC power supply 2 and the smoothing capacitor 5. The converter is configured to include, for example, a reactor and the above-mentioned upper and lower arm circuits 9. This configuration allows for voltage step-up and step-down.

[0031] The power conversion circuit 4 may include a snubber circuit. The snubber circuit is connected in parallel to the upper and lower arm circuits 9. The snubber circuit reduces the inductance of the upper and lower arm circuits 9. The snubber circuit absorbs a transient high voltage, known as a switching surge, that occurs when switching elements (MOSFETs 11) that constitute the upper and lower arm circuits 9. By providing the snubber circuit, the inverter 6 can perform high-speed switching.

[0032] <Power conversion device> FIG. 2 is a plan view showing an example of a power converter. FIG. 2 is a view of the power converter viewed from the semiconductor module side. FIG. 3 is a plan view of the power converter viewed from the filter module side. FIG. 4 is a plan view showing the filter module without the holding member. In FIG. 4, the holding member and support plate are omitted compared to FIG. 3. FIG. 5 is a cross-sectional view taken along line VV in FIG. 2. For convenience, in FIG. 5, the capacitor elements are indicated by metal hatching.

[0033] In the following, the mounting direction (stacking direction) of the filter module, semiconductor module, and capacitor module relative to the cooler is referred to as the Z direction. The direction perpendicular to the Z direction is referred to as the Y direction, and the direction perpendicular to both the X and Z directions is referred to as the X direction. The X, Y, and Z directions are mutually perpendicular. Unless otherwise specified, the shape viewed from the Z direction, in other words, the shape along the XY plane defined by the X and Y directions, is referred to as the planar shape. The planar view from the Z direction may sometimes be simply referred to as the planar view.

[0034] 2 to 5 provides the above-described power conversion circuit 4. The power conversion device 20 includes a cooler 30, a semiconductor module 40, a capacitor module 50, a current sensor 60, a circuit board 70, and a filter module 80.

[0035] The cooler 30 has one surface 30a and a back surface 30b. The back surface 30b is the surface opposite to the one surface 30a in the Z direction. Other elements constituting the power conversion device 20 are arranged on at least one of the one surface 30a and the back surface 30b. At least some of the other elements constituting the power conversion device 20 are fixed to the cooler 30. The cooler 30 is sometimes referred to as a support member. The cooler 30 may be at least part of a housing that houses the other elements constituting the power conversion device 20, or may be provided separately from the housing. The cooler 30 is formed using a metal material such as aluminum. The cooler 30 may be formed from a single member, or may be formed by assembling multiple members.

[0036] The cooler 30 is another element constituting the power conversion device 20 and has the function of cooling elements arranged on the cooler 30. The cooler 30 may be, for example, a heat sink. The heat sink may have fins on the back side. The cooler 30 may have a flow path through which a refrigerant flows. The refrigerant may be, for example, a phase-change refrigerant such as water or ammonia, or a phase-non-change refrigerant such as an ethylene glycol-based refrigerant. The refrigerant may be, for example, LLC. LLC is an abbreviation for long life coolant.

[0037] The illustrated cooler 30 has a case 31 and a cover 32. The case 31 has a recess 33 and a flow path 34. A capacitor module 50 is disposed in the recess 33. A part of the upper surface of the case 31 forms one surface 30a. The recess 33 is recessed relative to the surrounding portion of the upper surface of the case 31. Due to the presence of the recess 33, the back surface 30b has a stepped structure. The portion of the back surface 30b directly below the flow path 34 is recessed relative to the portion directly below the recess 33.

[0038] The flow path 34 opens to the upper surface of the case 31. A refrigerant inlet pipe and a refrigerant outlet pipe (not shown) are connected to the flow path 34. A refrigerant 35 flows through the flow path 34. The flow path 34 is provided so as to overlap with at least a portion of the semiconductor module 40 in a plan view. The flow path 34 is provided so as to encompass, for example, the main body 41 of the semiconductor module 40. The flow path 34 may be provided so as to overlap with the capacitor module 50 in a plan view.

[0039] The cover 32 closes the flow path 34. The cover 32 covers the opening of the case 31 and is fixed liquid-tightly to the surrounding area of ​​the opening. The cover 32 has fins 321 that extend in the Z direction from the rear surface of the cover 32 and are disposed within the flow path 34. The fins 321 are in contact with the refrigerant 35. The illustrated cover 32 has a plurality of pin-type fins 321. Although an example has been shown in which the cooler 30 includes the cover 32, this is not limiting. The semiconductor module 40 may also include a metal member (heat dissipation member) that covers the opening of the flow path 34.

[0040] The cooler 30 and the elements (components) arranged on the cooler 30 may be thermally connected via a bonding material such as solder, or via a thermally conductive member. The thermally conductive member is sometimes referred to as TIM. TIM is an abbreviation for Thermal Interface Material. GF may also be used as the thermally conductive member. GF is an abbreviation for Gap Filler.

[0041] The semiconductor modules 40 constitute the upper and lower arm circuits 9, i.e., the inverter 6. The semiconductor modules 40 may also be referred to as power modules, semiconductor devices, etc. The illustrated power conversion device 20 includes three semiconductor modules 40. The multiple semiconductor modules 40 include a semiconductor module 40U that constitutes the upper and lower arm circuits 9U, a semiconductor module 40V that constitutes the upper and lower arm circuits 9V, and a semiconductor module 40W that constitutes the upper and lower arm circuits 9W.

[0042] The semiconductor modules 40 have, for example, a common structure. The illustrated semiconductor module 40 includes a main body 41 and external connection terminals protruding from the main body 41. The main body 41 includes a semiconductor element 42, a sealing body 43, and the like.

[0043] The semiconductor element 42 is formed by forming a switching element on a semiconductor substrate made of silicon (Si) or a wide bandgap semiconductor with a wider bandgap than silicon. The switching element has a vertical structure so that the main current flows in the thickness direction of the semiconductor substrate. Examples of wide bandgap semiconductors include silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga2O3), and diamond.

[0044] The illustrated semiconductor element 42 is formed by forming the above-described n-channel MOSFET 11 and diode 12 on a semiconductor substrate made of SiC. The MOSFET 11 has a vertical structure so that a main current flows in the thickness direction of the semiconductor element 42 (semiconductor substrate). The semiconductor element 42 has main electrodes (not shown) on both sides in the thickness direction of the semiconductor element 42. The semiconductor element 42 has, as main electrodes, a source electrode on the front surface and a drain electrode on the back surface. The source electrode is formed on a part of the front surface. The drain electrode is formed on almost the entire back surface.

[0045] A main current flows between the drain electrode and the source electrode. The semiconductor element 42 has a pad (not shown) that is a signal electrode on the surface where the source electrode is formed. The semiconductor elements 42 are arranged so that their plate thickness direction is approximately parallel to the Z direction. One semiconductor module 40 includes, as semiconductor elements 42, three semiconductor elements 42H that form an upper arm 9H and three semiconductor elements 42L that form a lower arm 9L. The three semiconductor elements 42H that form one arm are lined up in the X direction. Similarly, the three semiconductor elements 42L are lined up in the X direction. The semiconductor elements 42H and semiconductor elements 42L that form one arm are lined up in the Y direction.

[0046] The sealing body 43 seals some of the other elements constituting the semiconductor module 40. The remaining portions of the other elements are exposed outside the sealing body 43. The illustrated sealing body 43 seals the semiconductor element 42, some of the external connection terminals, etc. Another portion of the external connection terminals protrudes outside the sealing body 43. The sealing body 43 is made of, for example, resin. The illustrated sealing body 43 is molded by transfer molding using epoxy resin. The sealing body 43 has a generally rectangular planar shape. The sealing body 43 forms the outer periphery of the main body 41. The sealing body 43 may be formed by potting. The sealing body 43 is filled into the storage space formed by the housing and the cooler 30 (not shown), and seals the semiconductor element 42 and other elements arranged in the storage space.

[0047] The external connection terminals are terminals for electrically connecting the semiconductor module 40 to an external device. The illustrated semiconductor module 40 includes main terminals 44 and signal terminals 45 as the external connection terminals. The main terminals 44 are electrically connected to main electrodes of the semiconductor element 42. The main terminals 44 include a P terminal 44P, an N terminal 44N, and an output terminal 44A.

[0048] The P-terminal 44P is electrically connected to the drain electrode of the semiconductor element 42H. The N-terminal 44N is electrically connected to the source electrode of the semiconductor element 42L. The P-terminal 44P and the N-terminal 44N are at least a part of the wiring that electrically connects the semiconductor element 42 and the capacitor element 51. The output terminal 44A is electrically connected to the connection point (midpoint) between the source electrode of the semiconductor element 42H and the drain electrode of the semiconductor element 42L. The output terminal 44A is at least a part of the wiring that electrically connects the semiconductor element 42 and the motor-generator 3.

[0049] The number and arrangement of the P terminal 44P, the N terminal 44N, and the output terminal 44A are not particularly limited. The illustrated semiconductor module 40 includes one P terminal 44P, one N terminal 44N, and one output terminal 44A. The P terminal 44P and the N terminal 44N extend from the main body 41 toward the capacitor module 50. The P terminal 44P and the N terminal 44N protrude to the outside from the surface of the main body 41 that faces the capacitor module 50. The P terminal 44P and the N terminal 44N are aligned in the X direction. The output terminal 44A extends from the main body 41 toward the current sensor 60. The output terminal 44A protrudes to the outside from the side opposite the surface that faces the capacitor module 50.

[0050] The signal terminals 45 are electrically connected to pads of the corresponding semiconductor elements 42. Of the illustrated signal terminals 45, the signal terminal 45 corresponding to the semiconductor element 42H protrudes to the outside from the side surface of the main body 41 facing the capacitor module 50. The signal terminal 45 corresponding to the semiconductor element 42L protrudes to the outside from the side surface of the main body 41 facing the current sensor 60. The signal terminals 45 are bent outside the sealing body 43 and extend upward in the Z direction, and are mounted on the circuit board 70.

[0051] In addition to the above-mentioned elements, the semiconductor module 40 also includes a wiring member (not shown). The wiring member provides a wiring function that electrically connects the main electrodes of the semiconductor element 42 to the main terminals 44. The wiring member provides a heat dissipation function that dissipates heat from the semiconductor element 42. The wiring member may be, for example, a substrate having a metal body disposed on one or both sides of an insulating base material, or may be a heat sink that is a metal member. The heat sink may be provided as part of the lead frame. The entire wiring member may be sealed by the sealing body 43, or a portion of the wiring member may be exposed from the sealing body 43. Exposing the wiring member can improve heat dissipation.

[0052] The semiconductor module 40 is disposed on one surface 30a of the cooler 30. The semiconductor module 40 is fixed to the cooler 30. The main body 41 of the semiconductor module 40 may be connected to the cooler 30 via a bonding material, or may be thermally connected to the cooler 30 via a heat conductive member. As shown in FIG. 2, the three semiconductor modules 40 are lined up in the X direction. The three semiconductor modules 40 are lined up in the order of semiconductor module 40U, semiconductor module 40V, and semiconductor module 40W. In addition, the side surfaces of adjacent semiconductor modules 40 face each other in the X direction with a predetermined gap therebetween.

[0053] The capacitor module 50 provides the smoothing capacitor 5 described above. The capacitor module 50 includes a capacitor element 51, a bus bar 52, and a sealing body 53. As illustrated, the capacitor module 50 may include a case 54. The capacitor module 50 is disposed on one surface 30a of the cooler 30. The capacitor module 50 is fixed to the cooler 30.

[0054] The capacitor element 51 is, for example, a film capacitor element. The capacitor element 51 has a generally rectangular shape in plan view. The capacitor element 51 has electrodes 55 on one surface and on the other back surface. The electrodes 55 are sometimes referred to as metallikon electrodes. One of the electrodes 55 is a P-electrode 55P, and the other is an N-electrode 55N. The illustrated capacitor element 51 is formed, for example, by winding a film around an axis generally parallel to the Z direction. In the illustrated capacitor element 51, the one surface and the back surface are surfaces in the Z direction. In other words, the back surface is the surface opposite the one surface in the Z direction. The back surface is the lower surface facing the bottom wall of a cylindrical case 54 that houses the sealing body 53, and the one surface is the upper surface. The capacitor element 51 has a negative N-electrode 55N on one surface and a positive P-electrode 55P on the back surface.

[0055] The capacitor module 50 may include only one capacitor element 51, or may include multiple capacitor elements 51. In a configuration including multiple capacitor elements 51, the capacitor elements 51 are aligned in at least one direction perpendicular to the Z direction. The illustrated capacitor module 50 includes four capacitor elements 51. The capacitor elements 51 are aligned in the X direction.

[0056] Busbar 52 is a metal plate made of a metal with good conductivity, such as Cu. Busbar 52 includes P busbar 52P and N busbar 52N. P busbar 52P is connected to P electrode 55P. N busbar 52N is connected to N electrode 55N. P busbar 52P and N busbar 52N are at least part of the wiring that electrically connects semiconductor element 42 and capacitor element 51. P busbar 52P and N busbar 52N each have an electrode connection portion 521, a terminal portion 522, and a coupling portion 523.

[0057] The electrode connection portions 521 are connection portions of the bus bar 52 with the corresponding electrodes 55. The terminal portions 522 are portions of the bus bar 52 that protrude outside the sealing body 53. The terminal portions 522 are portions for connection to the semiconductor module 40. The terminal portion 522 of the P bus bar 52P is connected to the P terminal 44P of the semiconductor module 40. The terminal portion 522 of the N bus bar 52N is connected to the N terminal 44N. The coupling portions 523 are portions of the bus bar 52 that connect the electrode connection portions 521 and the terminal portions 522.

[0058] The electrode connection portions 521 and the linking portions 523 are covered by the sealing body 53. The electrode connection portions 521 and the linking portions 523 are disposed inside the sealing body 53. The terminal portions 522 are disposed outside the sealing body 53. In the illustrated P bus bar 52P and N bus bar 52N, the plate thickness direction of the electrode connection portions 521 is approximately parallel to the Z direction. The linking portions 523 are continuous with the electrode connection portions 521, and include a portion that extends in the Y direction and a portion that extends in the Z direction. The linking portions 523 are approximately L-shaped in the YZ plane.

[0059] Terminal portion 522 extends from connecting portion 523 toward semiconductor module 40. Terminal portion 522 extends in the Y direction in a plan view. To reduce inductance, P bus bar 52P and N bus bar 52N are arranged to run parallel to each other and face each other over most of the entire length of terminal portion 522. Note that an insulating member may be arranged between terminal portion 522 of P bus bar 52P and terminal portion 522 of N bus bar 52N.

[0060] Sealing body 53 is made of an electrically insulating resin material. Sealing body 53 is formed by potting, for example. Sealing body 53 seals capacitor element 51. Sealing body 53 seals a portion of bus bar 52.

[0061] The case 54 may be formed using a metal material such as aluminum, or may be formed using a resin material. The illustrated case 54 is made of resin. The case 54 is cylindrical with a bottom. The case 54 has a bottom wall and a side wall continuous with the bottom wall. The case 54 is disposed on the surface 30a of the cooler 30 so that the outer surface of the bottom wall faces the surface 30a of the cooler 30 in the Z direction, specifically the bottom surface of the recess 33. The illustrated bottom wall has a generally rectangular shape in plan view with the X direction as the longitudinal direction. The side wall has a generally rectangular ring shape in plan view. Instead of the case 54, the cooler 30 may also serve as the case 54. The recess 33 of the cooler 30 is filled with a seal 53.

[0062] The illustrated capacitor module 50 further includes a DC terminal portion 56. The DC terminal portion 56 is a terminal portion for electrically connecting the capacitor element 51 and the semiconductor element 42 to the DC power supply 2. Like the bus bar 52, the DC terminal portion 56 is a metal plate made of a metal with good conductivity such as Cu. The DC terminal portion 56 includes a DC terminal portion 56P electrically connected to the P electrode 55P and a DC terminal portion 56N electrically connected to the N electrode 55N. The DC terminal portion 56 may be connected to the bus bar 52, or may be electrically connected to the electrode 55 without being connected to the bus bar 52. The DC terminal portion 56 may be connected to the P terminal 44P or the N terminal 44N.

[0063] The current sensor 60 provides the above-described current sensor 16. The current sensor 60 is configured to detect phase currents individually. The current sensor 60 may be a magnetic detection type sensor equipped with a magnetoelectric conversion element, or a resistance detection type sensor equipped with a shunt resistor. The illustrated current sensor 60 is a magnetic detection type. The current sensor 60 includes a main body 61 and bus bars 62 provided corresponding to each phase.

[0064] The illustrated main body 61 includes a Hall element 63, a core 64, a resin member 65, a substrate 66, and a signal terminal 67. The main body 61 includes three Hall elements 63 and three cores 64 corresponding to the busbar 62. The Hall elements 63 are mounted on the substrate 66 while being disposed in the gaps of the cores 64. The cores 64 are held by the resin member 65. The busbar 62 is held by the resin member 65 so as to pass through the annular region of the cores 64. The substrate 66 is fixed to the resin member 65 by crimping or the like (not shown). The signal terminal 67 is mounted on the substrate 66. The signal terminal 67 extends upward in the Z direction from the substrate 66 and is mounted on a circuit board 70. The signal terminal 67 electrically connects the substrate 66 and the circuit board 70. The busbar 62 extends in the Y direction in a plan view.

[0065] The current sensor 60 is disposed on one surface 30a of the cooler 30. The current sensor 60 is fixed to the cooler 30. The current sensor 60, the semiconductor module 40, and the capacitor module 50 are aligned in the Y direction. The semiconductor module 40 is disposed between the current sensor 60 and the capacitor module 50 in the Y direction.

[0066] The circuit board 70 provides at least the drive circuit 14 of the drive control unit 13 described above. The exemplary circuit board 70 provides the drive control unit 13 including the drive circuit 14 and the control circuit 15. The circuit board 70 includes a printed circuit board in which conductors are arranged on an insulating substrate, and electronic components and connectors mounted on the printed circuit board. The conductors include wiring elements. The wiring elements and electronic components form a circuit. The drive circuit 14 and the control circuit 15 are configured on the circuit board 70.

[0067] The circuit board 70 is disposed above the semiconductor module 40, the capacitor module 50, and the current sensor 60 so as to overlap with the semiconductor module 40, the capacitor module 50, and the current sensor 60 in a plan view. The circuit board 70 is disposed above the semiconductor module 40, the capacitor module 50, and the current sensor 60 by a support member (not shown). Other elements constituting the power conversion device 20 are electrically connected to the circuit board 70.

[0068] The filter module 80 provides the above-mentioned filter circuit 17. The filter module 80 constitutes an EMI filter. The filter module 80 is disposed on the rear surface 30b of the cooler 30. The filter module 80 is fixed to the cooler 30. The filter module 80 is a bus bar module including a bus bar 81 and a holding member 82. The illustrated filter module 80 includes a choke coil 83, a Y capacitor 84, and a discharge resistor 85.

[0069] Like the bus bars 52, the bus bars 81 are metal plates made of a metal with good conductivity, such as Cu. The bus bars 81 include a P bus bar 81P and an N bus bar 81N. The P bus bar 81P is electrically connected to the positive electrode of the DC power supply 2. The N bus bar 81N is electrically connected to the negative electrode of the DC power supply 2. The bus bar 81 has terminal portions 811 and 812. The terminal portion 811 is electrically connected to the DC power supply 2 (not shown). The terminal portion 812 is electrically connected to the corresponding DC terminal portion 56. The bus bars 81 electrically connect the DC power supply 2 and the DC terminal portion 56.

[0070] The terminal portions 811 include a terminal portion 811P of the P bus bar 81P and a terminal portion 811N of the N bus bar 81N. The thickness direction of the terminal portion 811 is approximately parallel to the Z direction. The terminal portion 811 extends in the Y direction in a plan view. The terminal portions 811P, 811N are lined up in the X direction with a predetermined gap between them so that their side surfaces face each other. The terminal portion 812 includes a terminal portion 812P of the P bus bar 81P and a terminal portion 812N of the N bus bar 81N. The thickness direction of the terminal portion 812 is approximately parallel to the Z direction. The terminal portion 812 extends in the X direction in a plan view. The terminal portions 812P, 812N are lined up in the Y direction with a predetermined gap between them so that their side surfaces face each other.

[0071] The bus bar 81 has opposing portions 813 and 814. The opposing portions 813 and 814 are portions of the bus bar 81 where the plate surfaces thereof face each other. The opposing portion 813 includes an opposing portion 813P of the P bus bar 81P and an opposing portion 813N of the N bus bar 81N. The bus bar 81 is arranged in the opposing portion 813 so that the opposing direction of the opposing portions 813 (813P, 813N) intersects with the Z direction in which the cooler 30 and the filter module 80 are aligned. The plate thickness direction of each of the illustrated opposing portions 813P and 813N is approximately parallel to the Y direction. The opposing portion 813 extends in the X direction in a plan view. The opposing portions 813P and 813N are aligned in the Y direction at a predetermined interval so that the plate surfaces thereof face each other. The opposing portions 813 face each other in the Y direction.

[0072] The facing portion 813 is arranged below the back surface 30b. At least a portion of the facing portion 813 is arranged in a recessed portion on the back surface 30b side of the cooler 30. The facing portion 813 is arranged such that the facing portion 813N faces the side wall that defines the recess 33 in the cooler 30 and is on the semiconductor module 40 side in the Y direction. The facing portion 813 is continuous with the terminal portion 811 described above. The terminal portion 811 is bent with respect to the facing portion 813 and extends in the Y direction from the lower end of the facing portion 813.

[0073] The facing portion 814 includes a facing portion 814P of the P bus bar 81P and a facing portion 814N of the N bus bar 81N. The plate thickness direction of each of the facing portions 814P, 814N is approximately parallel to the X direction. The facing portion 814 extends in the Y direction in a plan view. The facing portions 814P, 814N are lined up in the X direction with a predetermined gap between them so that their plate surfaces face each other. The facing portions 814 (814P, 814N) face each other in the X direction. The facing portion 814 is connected to one of the longitudinal ends of the facing portion 813. The connecting structure between the facing portions 813 and 814 is approximately L-shaped in plan view.

[0074] At least a portion of the facing portion 814 is disposed beside the side wall of the cooler 30 that defines the recess 33 and that faces the DC terminal portion 56 in the X direction. The facing portion 814 is disposed so that the side wall on the DC terminal portion 56 side faces the facing portion 814P. The facing portion 814 is continuous with the terminal portion 812 described above. The terminal portion 812 is one of the longitudinal ends of the facing portion 814 and is continuous with the end opposite the end on the facing portion 813 side. The terminal portion 812 is bent with respect to the facing portion 814 and extends in the X direction from the upper end of the facing portion 814.

[0075] The bus bar 81 has a Y capacitor connection portion 815 and a resistor connection portion 816. The Y capacitor connection portion 815 and the resistor connection portion 816 are continuous with the opposing portion 813. The Y capacitor connection portion 815 is electrically connected to the Y capacitor 84. The Y capacitor connection portion 815 includes a Y capacitor connection portion 815P of the P bus bar 81P and a Y capacitor connection portion 815N of the N bus bar 81N. The Y capacitor connection portion 815 is bent with respect to the opposing portion 813 and extends in the Y direction from the lower end of the opposing portion 813. The Y capacitor connection portion 815 extends in the same direction as the terminal portion 811 with respect to the opposing portion 813. The Y capacitor connection portion 815P is electrically connected to a P wiring 842P of the Y capacitor 84. The Y capacitor connection portion 815N is electrically connected to an N wiring 842N of the Y capacitor 84.

[0076] The resistor connection portion 816 is electrically connected to the discharge resistor 85. The resistor connection portion 816 includes a resistor connection portion 816P of the P bus bar 81P and a resistor connection portion 816N of the N bus bar 81N. The resistor connection portion 816 is bent with respect to the facing portion 813, and extends in the Y direction from the lower end of the facing portion 813. The resistor connection portion 816 extends in the opposite direction from the terminal portion 811 with respect to the facing portion 813. The resistor connection portions 816P, 816N are electrically connected to the discharge resistor 85. Both of the resistor connection portions 816P, 816N are generally L-shaped when viewed from above.

[0077] The holding member 82 holds the bus bar 81. The holding member 82 is a resin molded body. The holding member 82 is molded, for example, with the bus bar 81 as an insert part. The holding member 82 is fixed to the cooler 30. The holding member 82 may include a metal collar for fastening or the like as an insert part.

[0078] The choke coil 83 provides the choke coil 18 described above. The choke coil 83 is arranged below the rear surface 30b. At least a portion of the choke coil 83 is arranged in a recessed portion on the rear surface 30b side of the cooler 30. The choke coil 83 is arranged in a position overlapping with the terminal portion 811 in a plan view. The terminal portion 811 is arranged so as to pass through the choke coil 83. The choke coil 83 is electrically connected to the bus bar 81 (terminal portion 811).

[0079] The Y capacitor 84 provides the above-mentioned Y capacitor 19. The Y capacitor 84 is arranged below the rear surface 30b. At least a portion of the Y capacitor 84 is arranged in a recessed portion on the rear surface 30b side of the cooler 30. The Y capacitor 84 and the choke coil 83 are aligned in the X direction in a plan view. The Y capacitor 84 has a capacitor element 841 and wiring 842.

[0080] The wiring 842 includes a P wiring 842P, an N wiring 842N, and a ground wiring 842G. The P wiring 842P, the N wiring 842N, and the ground wiring 842G extend generally in the Y direction. The P wiring 842P, the N wiring 842N, and the ground wiring 842G are aligned in the X direction such that the ground wiring 842G is located between the P wiring 842P and the N wiring 842N. The N wiring 842N is disposed on the choke coil 83 side. The ground wiring 842G is electrically connected to a ground potential that serves as a reference in the vehicle. The ground wiring 842G is electrically connected to, for example, the cooler 30.

[0081] The capacitor element 841 includes a first element electrically connected to the P wiring 842P and the ground wiring 842G, and a second element electrically connected to the N wiring 842N and the ground wiring 842G. The first element provides a Y capacitor 19 on the P line 7 side. The second element provides a Y capacitor 19 on the N line 8 side. The number of each of the first element and the second element may be one or more. The illustrated Y capacitor 84 includes a plurality of first elements having different capacitances and a plurality of second elements having different capacitances.

[0082] The discharge resistor 85 provides a discharge resistance that discharges the charge accumulated in the smoothing capacitor 5, for example, to reduce the voltage between the terminals of the smoothing capacitor 5 to a predetermined voltage. Although omitted in FIG. 1, one end of the discharge resistor is electrically connected to the P line 7, and the other end is electrically connected to the N line 8. The discharge resistor is connected in parallel to the smoothing capacitor 5. When the supply of power from the DC power supply is cut off, for example, the discharge resistor forcibly (rapidly) discharges the charge accumulated in the smoothing capacitor 5. The discharge resistor discharges the charge and consumes it as heat.

[0083] The discharge resistor 85 is disposed below the rear surface 30b. At least a portion of the discharge resistor 85 is disposed directly below the bottom wall that defines the recess 33 in the cooler 30. The discharge resistor 85, the choke coil 83, and the Y capacitor 84 are aligned in the Y direction in a plan view. The illustrated discharge resistor 85 is connected to the resistor connection portion 816 while being disposed on a metal support plate 86. The support plate 86 is fixed to the holding member 82.

[0084] <Heat dissipation structure of filter module> 6 is an enlarged view of region VI in FIG. 5. As described above, the opposing direction of the opposing portion 813 is the Y direction. The opposing portions 813P and 813N face each other in the Y direction. The opposing direction of the opposing portion 813 is not parallel to the Z direction, which is the stacking direction of the cooler 30 and the filter module 80. The bus bar 81 is arranged so that the opposing direction of the opposing portion 813 intersects with the stacking direction of the cooler 30 and the filter module 80. In each of the opposing portions 813P and 813N, one of the plate surfaces is an opposing surface 81a that faces each other, and the other plate surface is a back surface 81b opposite to the opposing surface 81a.

[0085] The holding member 82 has one surface 82a and a back surface 82b. The one surface 82a is the surface facing the back surface 30b of the cooler 30. The back surface 82b is the surface opposite to the one surface 82a. The holding member 82 has a recess 821 that opens to the one surface 82a.

[0086] The recess 821 is provided so as to overlap the facing portion 813 in a plan view in the facing direction (Y direction) of the facing portion 813. The recess 821 is provided between the plate surfaces of the facing portion 813. The recess 821 is provided between the facing surface 81a of the facing portion 813P and the facing surface 81a of the facing portion 813N. The recess 821 is provided in an overlapping region (facing region) of the facing portions 813P and 813N. The recess 821 may extend continuously along the X direction, which is the extension direction of the facing portion 813, or may be provided discontinuously along the facing portion 813.

[0087] The recess 821 may be shallower than the lower end of the facing portion 813, or may be located at approximately the same position as the lower end of the facing portion 813. The recess 821 may be deeper than the lower end of the facing portion 813. The illustrated recess 821 is provided slightly shallower than the lower end of the facing portion 813.

[0088] The holding member 82 has a bottom wall 822 and side walls 823 as wall portions that define the recess 821. The bottom wall 822 defines the bottom surface of the recess 821. The side walls 823 define the side surfaces of the recess 821. One of the side walls that sandwich the recess 821 in the Y direction holds a facing portion 813P, and the other side wall holds a facing portion 813N. The side walls cover the facing portion 813.

[0089] As shown in FIGS. 5 and 6, the power conversion device 20 includes a heat conduction member 90. The heat conduction member 90 transfers heat from the bus bar 81 due to current flow to the cooler 30. The heat conduction member 90 thermally connects the bus bar 81 to the cooler 30. The heat conduction member 90 is a heat dissipation member that dissipates heat from the bus bar 81. The heat conduction member 90 contains a material with higher thermal conductivity than the holding member 82. An example of the heat conduction member 90 is GF (gap filler). GF has fluidity before hardening.

[0090] The heat conduction member 90 is disposed at least in the recess 821. The heat conduction member 90 fills the recess 821. The heat conduction member 90 is disposed in the recess 821 in a fluid state and hardens while filling the recess 821. The illustrated heat conduction member 90 has a first heat conduction portion 91 and a second heat conduction portion 92. The first heat conduction portion 91 is a portion disposed in the recess 821. The second heat conduction portion 92 is a portion interposed between the rear surface 30b of the cooler 30 and one surface 82a of the holding member 82. The heat conduction member 90 is substantially T-shaped in the YZ plane. The second heat conduction portion 92 is disposed so as to sandwich the first heat conduction portion in the Y direction. The second heat conduction portion 92 is disposed at a position overlapping the opposing portion 813 in a plan view. The illustrated heat conducting member 90 has a portion (third heat conducting portion) disposed directly above the first heat conducting portion 91 and between the two second heat conducting portions 92.

[0091] The length L1 of the first thermally conductive portion 91 in the depth direction of the recess 821 is equal to the depth of the recess 821. The length of the second thermally conductive portion 92 in the facing direction is the sum of the length L21 and the length L22. The length L1 of the first thermally conductive portion 91 is equal to or greater than the length (L21+L22) of the second thermally conductive portion 92. In the exemplary thermally conductive member 90, the length L1 of the first thermally conductive portion 91 is longer than the length (L21+L22) of the second thermally conductive portion 92.

[0092] The illustrated holding member 82 further has a through-hole 824 and a recess 825. The through-hole 824 is provided in the bottom wall 822. The through-hole 824 opens to the bottom surface of the recess 821 and communicates with the inside of the recess 821. The through-hole 824 penetrates the bottom wall 822 in the Z direction. The through-hole 824 is a hole for allowing air in the recess 821 to escape to the outside of the holding member 82 when the thermally conductive member 90 is filled in the recess 821. It is preferable that the through-hole 824 has a diameter sufficient to prevent the thermally conductive member 90, which has fluidity, from flowing out through the through-hole 824.

[0093] The recess 825 opens to the back surface 82b. The recess 825 is provided at a position overlapping the recess 821 in a plan view. A bottom wall 822 is located between the recess 825 and the recess 821. The bottom wall 822 also defines the bottom surface of the recess 825. The bottom wall 822 is an intermediate wall that is continuous with the side wall 823 at a position away from both ends of the side wall 823 in the Z direction. The through hole 824 communicates with the recess 821 and the recess 825.

[0094] As described above, length L1 of first thermally conductive portion 91 is equal to the depth of recess 821. Recess 821 is deeper than recess 825. In other words, length L1 (depth) of recess 821 is longer than length L3 (depth) of recess 825.

[0095] The heat dissipation structure (cooling structure) described above can be realized, for example, by arranging GF, which is heat conductive member 90, on one surface 82a around recess 821. Because GF has fluidity before hardening, it flows from on one surface 82a into recess 821 located below one surface 82a. By adjusting the amount of GF so that GF remains on one surface 82a when recess 821 is filled with GF, heat conductive member 90 having first heat conductive portion 91 and second heat conductive portion 92 can be arranged.

[0096] <Summary of the First Embodiment> The power conversion device 20 of this embodiment includes a cooler 30, a busbar module, and a heat-conducting member 90. The busbar module has a busbar 81 including opposing portions 813 whose plate surfaces face each other, and a holding member 82 that holds the busbar 81, and is disposed on the cooler 30. The busbar 81 is disposed so that the arrangement direction of the cooler 30 and the busbar module intersects with the opposing direction of the opposing portions 813. The holding member 82 has an opening on one surface 82a that faces the cooler 30, and a recess 821 provided between the opposing portions 813 so as to overlap with the opposing portions 813 in a plan view in the opposing direction. The heat-conducting member 90 is disposed in the recess 821.

[0097] In this way, the facing portions 813 are provided so that the plate surfaces face each other, and the bus bars 81 are arranged so that the facing direction of the facing portions 813 intersects with the arrangement direction of the cooler 30 and the bus bar modules. Therefore, compared to a configuration in which the facing portions 813 are provided so that the side surfaces face each other and the plate surfaces of the facing portions 813 face the cooler 30, the size of the bus bar modules, and therefore the power conversion device 20, in the facing direction can be made smaller.

[0098] Furthermore, a recess 821 is provided between the plate surfaces of the opposing portion 813 of the holding member 82, and the heat conduction member 90 is disposed in the recess 821. As a result, even with the bus bar 81 disposed as described above, it is possible to ensure the opposing area between the heat conduction member 90 and the bus bar 81, i.e., the heat dissipation area. Heat generated by the bus bar 81 can be effectively dissipated via the heat conduction member 90. As a result, it is possible to reduce the size of the device while ensuring heat dissipation. In the illustrated power conversion device 20, the filter module 80 corresponds to the bus bar module.

[0099] As illustrated, bus bar 81 may include a first bus bar and a second bus bar, and facing portion 813 may have a first facing portion of the first bus bar and a second facing portion of the second bus bar. Recess 821 may be provided between the first facing portion and the second facing portion. In this way, by providing recess 821 between the plate surfaces of facing portion 813 of the two bus bars, it is possible to reduce the physical size while ensuring heat dissipation in a configuration including two bus bars.

[0100] As shown in the example, one of the first bus bar and the second bus bar may be a P bus bar electrically connected to the positive electrode of the DC power supply 2, and the other of the first bus bar and the second bus bar may be an N bus bar electrically connected to the negative electrode of the DC power supply 2. Bus bar 81P corresponds to the P bus bar, and bus bar 81N corresponds to the N bus bar. As the output of power conversion device 20 increases, the heat generated by the P bus bar and the N bus bar also increases. By providing recess 821 between the plate surfaces of opposing portion 813 of the P bus bar and the N bus bar, it is possible to reduce the size of the power conversion device 20 while reducing the impact of the heat from the P bus bar and the N bus bar on other elements that make up the power conversion device 20.

[0101] As illustrated, the filter module 80 constituting the EMI filter (filter circuit 17) may be a bus bar module. This can reduce the size of the filter module 80 and reduce the influence of heat from the bus bars 81P, 81N of the filter module 80 on other elements constituting the power conversion device 20, such as the Y capacitor 84.

[0102] As illustrated, the heat conduction member 90 may have a first heat conduction portion 91 disposed in the recess 821 and a second heat conduction portion 92 interposed between one surface 82a of the holding member 82 and the cooler 30. This allows heat generated in the bus bar 81 to be dissipated from the plate surface via the first heat conduction portion 91 and from the end surface via the second heat conduction portion 92. In other words, heat dissipation can be improved.

[0103] As shown in the example, the length of the first thermally conductive portion 91 in the depth direction of the recess 821 may be equal to or greater than the length of the second thermally conductive portion 92 in the opposing direction. Compared to a configuration in which the length of the first thermally conductive portion 91 is shorter than the length of the second thermally conductive portion 92, this configuration increases the heat dissipation area in the depth direction, thereby improving heat dissipation. By making the length of the first thermally conductive portion 91 longer than the length of the second thermally conductive portion 92, the effect can be enhanced.

[0104] As shown in the example, a gap filler that has fluidity before hardening may be used as the thermal conductive member 90. This makes it easier to fill the thermal conductive member 90 into the recess 821. Furthermore, by hardening the material in the filled state, the thermal conductive member 90 can be held in a predetermined position.

[0105] As illustrated, through-holes 824 may be provided in bottom wall 822 that defines the bottom surface of recess 821 in holding member 82. This makes it easier for air to escape from recess 821 when heat conduction member 90 having fluidity is placed in recess 821. In other words, it is easier to place heat conduction member 90 in recess 821.

[0106] As illustrated, the holding member 82 may have a recess 825 that opens to the rear surface 82b in addition to the recess 821, and the bottom wall 822 may also define the bottom surface of the recess 825. The recess 821 corresponds to the first recess, and the recess 825 corresponds to the second recess. This shortens the length of the through hole 824. Therefore, it is easier to arrange the heat conduction member 90 in the recess 821 compared to a configuration in which the through hole 824 opens to the rear surface 82b.

[0107] As shown in the example, the recess 821 may be configured to be deeper than the recess 825. This allows the air inside the recess 821 to be easily released, and the heat dissipation area can be increased.

[0108] <Modification> Although an example has been shown in which the holding member 82 has the recess 825, this is not limiting. As shown in Fig. 7, the holding member 82 may not have the recess 825, and the through-hole 824 may open on the rear surface 82b. Although not shown, the holding member 82 may not have the through-hole 824 or the recess 825.

[0109] Although the example in which the heat conduction member 90 has the first heat conduction portion 91 and the second heat conduction portion 92 has been described, the present invention is not limited to this. As shown in Fig. 8, the heat conduction member 90 may not have the second heat conduction portion 92. In Fig. 8, the heat conduction member 90 extends above the one surface 82a, but the heat conduction member 90 may be arranged so that the upper end of the heat conduction member 90 is substantially flush with the one surface 82a. In other words, the heat conduction member 90 may have only the first heat conduction portion 91.

[0110] The busbar module is not limited to the filter module 80. The busbar module may be any module that includes busbars having opposing portions where the plate surfaces face each other, and a holding member that holds the busbars. For example, the capacitor module 50 may be configured as a busbar module by providing a holding member that holds the busbar 52 (terminal portion 522) in the capacitor module 50. The current sensor 60, which includes the busbar 62 and the resin member 65 (holding member), may also be configured as a busbar module. Alternatively, an input terminal block or an output terminal block may also be configured as a busbar module.

[0111] The facing portion 813 is not limited to a facing portion formed by two bus bars 81. As shown in Fig. 9, the facing portion may be formed by a single bus bar. In Fig. 9, one bus bar 81 is folded back to form a substantially U-shape in the YZ plane. A recess 821 is provided between the facing pieces of the U-shaped bus bar 81.

[0112] Although GF is used as an example of the heat conducting member 90 having fluidity, the heat conducting member 90 is not limited to this. The heat conducting member 90 may be a material that does not undergo a hardening treatment, such as grease or gel.

[0113] Bus bar 81 may be fixed by press fitting. In facing portion 813, bus bar 81 may define at least a part of the side surface of recess 821. In other words, bus bar 81 may be exposed in recess 821.

[0114] (Second embodiment) This embodiment is a modification of the previous embodiment, and the description of the previous embodiment can be used. In the previous embodiment, a heat conductive member having fluidity is disposed in the recess. In addition, a structure that allows the heat conductive member to be easily filled in the recess may be used.

[0115] FIG. 10 is an enlarged view of the periphery of the opposing portion in the power converter according to this embodiment. FIG. 10 corresponds to FIG. 6. The illustrated holding member 82 has a rib 826. The rib 826 protrudes from the one surface 82a toward the cooler 30 and is provided so as to surround the opening of the recess 821. The rib 826 extends in the Z direction. The rib 826 may be provided continuously and in an annular shape, or may be discontinuous and in an annular shape. The illustrated rib 826 is continuous and in an annular shape, and at least a portion of the upper end (protruding tip) of the rib 826 contacts the back surface 30b. The heat conduction member 90 is disposed in a restricted area defined by the back surface 30b of the cooler 30, the inner circumferential surface of the rib 826, the one surface 82a inside the rib 826, and the surface of the recess 821.

[0116] The position of the rib 826 in the opposing direction (Y direction) is not particularly limited. For example, it may be provided at a position overlapping the opposing surface 81a in a plan view, or at a position overlapping the back surface 81b. It may be provided at a position closer to the opposing surface 81a than the back surface 81b. It may be provided more inward than the opposing surface 81a. It may be provided more outward than the back surface 81b. The exemplified rib 826 is provided at a position closer to the back surface 81b than the opposing surface 81a. The other configurations are the same as those described in the preceding embodiment.

[0117] <Summary of the second embodiment> As illustrated, the holding member 82 may be provided with a rib 826 that protrudes from one surface 82a toward the cooler 30 and surrounds the opening of the recess 821. This allows the heat conduction member 90, which has fluidity, to be placed in a restricted area that includes the rib 826. This prevents the heat conduction member 90 from escaping in a direction away from the opening of the recess 821, thereby preventing a decrease in heat dissipation.

[0118] As shown in the example, the rib 826 may be provided at a position closer to the rear surface 81b than to the facing surface 81a in the facing direction. This provides a restricted area that overlaps with at least a portion of the end surface of the facing portion 813 in a plan view, making it easier to position the second heat-conducting portion 92 directly above the end surface of the facing portion 813. Heat can also be dissipated from the end surface of the facing portion 813 via the second heat-conducting portion 92, improving heat dissipation.

[0119] <Modification> 11, the cooler 30 may be provided with a recess 36 into which the rib 826 fits. The recess 36 corresponds to a cooler recess. The rib 826 fits into the recess 36, forming a labyrinth structure, which makes it even more difficult for the fluid heat conduction member 90 to escape outside the restricted area.

[0120] (Third embodiment) This embodiment is a modification based on the previous embodiment, and the description of the previous embodiment can be used. In the previous embodiment, ribs are provided on the holding member. Instead of or in addition to this, a structure that makes it easy to fill the recess with the thermal conductive member may be provided in addition to the ribs.

[0121] FIG. 12 is an enlarged view of the periphery of the opposing portion in the power conversion device according to this embodiment. FIG. 12 corresponds to FIG. 6. The illustrated holding member 82 has a chamfered portion 827. The chamfered portion 827 is, for example, a C-chamfered portion. The chamfered portion 827 is provided at the corner formed by the one surface 82a and the side surface of the recess 821. By having the chamfered portion 827, the opening area of ​​the recess 821 increases with increasing distance from the bottom surface of the recess 821 within a predetermined range in the depth direction (Z direction) from the one surface 82a. In other words, the opening area of ​​the recess 821 increases on the one surface 82a side. The other configurations are similar to those described in the preceding embodiment.

[0122] <Summary of the third embodiment> As shown in the example, the opening area of ​​recess 821 may be increased in a predetermined range in the depth direction from one surface 82a as it gets farther from the bottom surface of recess 821. This makes it easier for heat conduction member 90, which has fluidity, to flow into recess 821. In other words, it is easier to arrange heat conduction member 90 in recess 821.

[0123] (Other embodiments) The disclosure in this specification and drawings, etc. is not limited to the exemplified embodiments. The disclosure encompasses the exemplified embodiments and modifications thereto by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and / or elements shown in the embodiments. The disclosure can be implemented in various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure encompasses the omission of parts and / or elements from the embodiments. The disclosure encompasses the substitution or combination of parts and / or elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. Some disclosed technical scopes are defined by the claims, and should be interpreted as including all modifications within the meaning and scope equivalent to the claims.

[0124] The disclosure in the specification, drawings, etc. is not limited by the claims. The disclosure in the specification, drawings, etc. encompasses the technical ideas described in the claims, and extends to more diverse and broader technical ideas than the technical ideas described in the claims. Therefore, various technical ideas can be extracted from the disclosure in the specification, drawings, etc. without being bound by the claims.

[0125] When an element or layer is referred to as being "on," "coupled," "connected," or "bonded," it may be directly on, coupled, connected, or bonded to another element or layer, and intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly coupled," "directly connected," or "directly bonded" to another element or layer, no intervening elements or layers are present. Other terms used to describe relationships between elements should be construed in a similar manner (e.g., "between" vs. "directly between," "adjacent" vs. "directly adjacent," etc.). As used in this specification, the term "and / or" includes any and all combinations of one or more of the associated listed items. That is, reference to A and / or B means at least one of A and B.

[0126] Spatially relative terms such as "inside," "outside," "back," "below," "low," "top," "top," and the like are used herein to facilitate the description of one element or feature's relationship to other elements or features, as illustrated. Spatially relative terms may be intended to encompass different orientations of the device during use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures were turned over, elements described as "below" or "directly below" other elements or features would then be oriented "above" the other elements or features. Thus, the term "bottom" can encompass both an orientation of top and bottom. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used in this specification would be interpreted accordingly. [Explanation of symbols]

[0127] 1... drive system, 2... DC power supply, 3... motor generator, 3a... winding, 4... power conversion circuit, 5... smoothing capacitor, 6... inverter, 7... P line, 8... N line, 9, 9U, 9V, 9W... upper and lower arm circuits, 9H... upper arm, 9L... lower arm, 10... output line, 11... MOSFET, 12... diode, 13... drive control unit, 14... drive circuit, 15... control circuit, 16... current sensor, 17... filter circuit, 18... choke coil, 19... Y capacitor, 20... power conversion device, 30... cooler, 30a... one side, 30 b...back surface, 31...case, 32...cover, 321...fins, 33, 36...recess, 34...flow path, 35...refrigerant, 40, 40U, 40V, 40W...semiconductor module, 41...main body, 42, 42H, 42L...semiconductor element, 43...sealing body, 44...main terminal, 44A...output terminal, 44N...N terminal, 44P...P terminal, 45...signal terminal, 50...capacitor module, 51...capacitor element, 52...bus bar, 52N...N bus bar, 52P...P bus bar, 521...electrode connection portion, 522...terminal portion, 523...connecting portion, 53...sealing body, 54...Case, 55...Electrode, 55N...N electrode, 55P...P electrode, 56, 56N, 56P...DC terminal portion, 60...Current sensor, 61...Main body portion, 62...Bus bar, 63...Hall element, 64...Core, 65...Resin member, 66...Substrate, 67...Signal terminal, 70...Circuit board, 80...Filter module, 81...Bus bar, 81a...Opposite surface, 81b...Back surface, 81N...N bus bar, 81P...P bus bar, 811, 811N, 811P, 812, 812N, 812P...Terminal portion, 813, 813N, 813P, 814, 814N, 814P ...Facing portion, 815, 815N, 815P...Y capacitor connection portion, 816, 816N, 816P...Resistor connection portion, 82...Holding member, 82a...One surface, 82b...Back surface, 821, 825...Recess, 822...Bottom wall, 823...Side wall, 824...Through hole, 826...Rib, 827...Chamfered portion, 83...Choke coil, 84...Y capacitor, 841...Capacitor element, 842...Wiring, 842G...Ground wiring, 842N...N wiring, 842P...P wiring, 85...Discharge resistor, 86...Support plate, 90...Heat conductive member, 91...First heat conductive portion, 92...Second heat conductive portion

Claims

1. A cooler (30); a busbar module (80) including busbars (81) including opposing portions (813) where the plate surfaces face each other, and a holding member (82) that holds the busbars, the busbar module (80) being disposed on the cooler; a heat conduction member (90) that transfers heat from the bus bar to the cooler; Equipped with the bus bar is arranged so that an arrangement direction of the cooler and the bus bar module intersects with an opposing direction of the opposing portions; the holding member has a recess (821) that opens to one surface (82a) that is the surface on the cooler side and is provided between the opposing portions so as to overlap with the opposing portions in a plan view in the opposing direction, The heat conduction member is disposed in the recess.

2. The bus bars include a first bus bar (81P) and a second bus bar (81N), the opposing portion includes a first opposing portion (813P) of the first bus bar and a second opposing portion (813N) of the second bus bar, The power conversion device according to claim 1 , wherein the recess is provided between the first opposing portion and the second opposing portion.

3. 3. The power conversion device according to claim 2, wherein one of the first bus bar and the second bus bar is a P bus bar electrically connected to a positive electrode of a DC power supply, and the other of the first bus bar and the second bus bar is an N bus bar electrically connected to a negative electrode of the DC power supply.

4. The power conversion device according to claim 3 , wherein the bus bar module is a filter module that constitutes an EMI filter.

5. The power conversion device according to any one of claims 1 to 4, wherein the heat conduction member has a first heat conduction portion (91) arranged in the recess and a second heat conduction portion (92) interposed between the one surface and the cooler.

6. The power conversion device according to claim 5 , wherein a length of the first heat conducting portion in a depth direction of the recess is equal to or greater than a length of the second heat conducting portion in the opposing direction.

7. 5. The power conversion device according to claim 1, wherein the heat conducting member is a gap filler that has fluidity before hardening.

8. The power conversion device according to claim 7, wherein the holding member has a rib (826) that protrudes from the one surface toward the cooler and is provided so as to surround an opening of the recess.

9. The bus bar has, as the plate surface of the opposing portion, an opposing surface (81a) and a surface (81b) opposite to the opposing surface, The power conversion device according to claim 8 , wherein the rib is provided at a position closer to the opposite surface than to the opposing surface in the opposing direction.

10. The power conversion device according to claim 7, wherein the holding member has a through-hole (824) provided in a bottom wall (822) that defines a bottom surface of the recess.

11. The holding member has a first recess which is the recess and a second recess (825) which opens to the back surface, The power conversion device according to claim 10 , wherein the bottom wall also defines a bottom surface of the second recess.

12. The power conversion device according to claim 11 , wherein the first recess is deeper than the second recess.

13. The power conversion device according to claim 7 , wherein an opening area of ​​the recess increases with increasing distance from the bottom surface within a predetermined range in the depth direction from the one surface.

14. The power conversion device according to claim 8, wherein the cooler has a cooler recess (36) into which the rib fits.

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