Cooler and power conversion device

Abstract

In the present invention, a case includes a second refrigerant passage (720) that provides communication between a first refrigerant passage (710) extending in the Y direction and a third refrigerant passage (730) extending in the X direction. The third refrigerant passage is positioned above the first refrigerant passage in the Z direction and is separated from the first refrigerant passage in the Y direction. The second refrigerant passage is defined by: a second bottom surface in which a first communication hole (751) opens, the first communication hole (751) allowing a refrigerant from the first refrigerant passage to flow into the second refrigerant passage; a second top surface which is positioned above the second bottom surface in the Z direction and in which a second communication hole (752) opens, the second communication hole (752) allowing the refrigerant to flow out of the second refrigerant passage into the third refrigerant passage; and a second annular surface connecting the second bottom surface and the second top surface. A part of the second annular surface is an inclined surface on which a separation distance in the Z direction from the second communication hole gradually decreases from the first communication hole toward the second communication hole in the Y direction. The inclined surface and the first communication hole are aligned with each other in the Y direction. The second communication hole is longer in the Y direction than in the X direction.

Description

Cooler and power conversion device CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2024-111134 filed in Japan on July 10, 2024, the contents of which are incorporated by reference in their entirety.

[0002] The disclosure described herein relates to a cooler and a power conversion device.

[0003] Patent Document 1 discloses an electric work vehicle that is provided with a cooling path for cooling an inverter.

[0004] Japanese Patent Application Laid-Open No. 2023-95635

[0005] In the electric work vehicle of Patent Document 1, a refrigerant flows through the hollow portion of the cooling passage. The refrigerant flows through the cooling passage by an electric pump. The refrigerant flows in the extension direction of the cooling passage, but if the extension direction is changed from a linear direction, the refrigerant collides with the wall surface that defines the cooling flow path, which reduces the flow rate of the refrigerant.

[0006] An object of the present disclosure is to provide a cooler and a power conversion device in which a decrease in the flow velocity of a refrigerant is suppressed.

[0007] The disclosed aspect is a cooler having a communicating flow path that communicates a first cooling flow path that cools a first component included in a power conversion circuit and a second cooling flow path that cools a second component included in the power conversion circuit, wherein the first cooling flow path extends in a vertical direction perpendicular to the vertical direction, and the second cooling flow path extends in a horizontal direction perpendicular to the vertical and vertical directions, the second cooling flow path is located vertically above the first cooling flow path and is separated from the first cooling flow path in the vertical direction, the communicating flow path is defined by a connecting surface that connects an inlet through which refrigerant that has flowed through the first cooling flow path flows, and an outlet that is located vertically above the inlet and separated from it in the vertical direction, and through which the refrigerant that has flowed into the inlet flows out to the second cooling flow path, and a part of the connecting surface is a slope that gradually becomes shorter vertically as it approaches the outlet from the inlet, and the slope and the inlet are aligned vertically, and the outlet is longer vertically than horizontally.

[0008] The disclosed aspect is a power conversion device having a power conversion circuit and a cooler that cools the power conversion circuit, wherein the power conversion circuit has a first component and a second component, and the cooler includes a first cooling flow path that cools the first component, a second cooling flow path that cools the second component, and a communication flow path that communicates the first cooling flow path and the second cooling flow path, wherein the first cooling flow path extends in a longitudinal direction perpendicular to the vertical direction, and the second cooling flow path extends in a transverse direction perpendicular to the vertical and longitudinal directions, and the second cooling flow path is located vertically above the first cooling flow path and is spaced apart from the first cooling flow path in the longitudinal direction, and the communication flow path is defined by a connection surface that connects an inlet into which a refrigerant that has flowed through the first cooling flow path flows, and an outlet that is located vertically above the inlet and spaced apart from the inlet in the longitudinal direction, and through which the refrigerant that has flowed into the inlet flows out into the second cooling flow path, Part of the connecting surface is a slope in which the vertical distance from the outlet gradually decreases as it approaches the inlet in the vertical direction, the slope and the inlet are aligned vertically, and the outlet is longer vertically than horizontally.

[0009] This allows the flow direction of the refrigerant flowing vertically through the first cooling channel to be converted between vertical and horizontal directions, and then flow into the second cooling channel extending horizontally. The shape of the sloped surface prevents a decrease in the flow rate of the refrigerant due to collisions. The shape of the outlet facilitates the flow of the refrigerant into the second cooling channel extending horizontally. As a result, a decrease in the flow rate of the refrigerant flowing into the second cooling channel is prevented.

[0010] The reference numbers in parentheses above merely indicate the corresponding relationship with the configurations described in the embodiments below, and do not in any way limit the technical scope.

[0011] FIG. 3 is a circuit diagram for explaining an in-vehicle system. FIG. 4 is a perspective view for explaining a case and a refrigerant passage. FIG. 5 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 6 is a cross-sectional view taken along line IV-IV in FIG. 2. FIG. 7 is a schematic view for explaining a refrigerant passage. FIG. 8 is a top view for explaining a third refrigerant passage. FIG. 9 is a top view for explaining a third refrigerant passage.

[0012] Hereinafter, several embodiments for carrying out the present disclosure will be described with reference to the drawings. Portions corresponding to matters described in the previous embodiments may be assigned the same reference numerals in the subsequent embodiments, and duplicated descriptions may be omitted. When only a portion of the configuration is described in each embodiment, the description of the previous embodiment may be applied to the remaining portions of the configuration.

[0013] In each embodiment, it is possible to combine parts that are specifically expressly permitted to be combined with each other. Furthermore, even if it is not explicitly stated that a combination is possible, it is also possible to partially combine multiple embodiments, an embodiment and a variation, or multiple variation embodiments, as long as there is no particular problem with the combination.

[0014] In the following description, the three mutually orthogonal directions are referred to as the X, Y, and Z directions. The X, Y, and Z directions are linear directions. In the drawings, the "directions" are omitted and the directions are simply shown as X, Y, and Z. The flow direction of the refrigerant, which will be described later, is indicated by solid arrows in the drawings.

[0015] When the present disclosure is mounted on a vehicle, the X direction is along the left-right direction of the vehicle. The Y direction is along the forward and backward direction of the vehicle. The Z direction is along the vertical direction of the vehicle. When the vehicle is parked on a horizontal surface, the plane defined by the X direction and the Y direction is along the horizontal direction. The Z direction is along the vertical direction. In the following, embodiments will be described on the assumption that the plane defined by the X direction and the Y direction is along the horizontal direction and the Z direction is along the vertical direction. The X direction corresponds to the horizontal direction. The Y direction corresponds to the vertical direction.

[0016] First Embodiment In-Vehicle System First, an in-vehicle system 100 to which a power conversion device 300 is applied will be outlined with reference to Fig. 1. The in-vehicle system 100 is a system for an electric vehicle. The in-vehicle system 100 has a battery 200, a power conversion device 300, and a motor 400.

[0017] The in-vehicle system 100 also has multiple ECUs (not shown). These multiple ECUs transmit and receive signals to each other via bus wiring. The multiple ECUs cooperate to control the electric vehicle. The power running and regeneration of the motor 400 are controlled according to the SOC of the battery 200 through the control of the multiple ECUs. ECU stands for electronic control unit. SOC stands for state of charge.

[0018] The ECU has at least one central processing unit (CPU) and at least one memory device (MMR) as a recording medium for recording programs and data. The ECU is provided by a microcomputer equipped with a computer-readable recording medium. The recording medium is a non-transitory tangible recording medium that non-temporarily stores a computer-readable program. The recording medium can be provided as a semiconductor memory, a magnetic disk, or the like.

[0019] Battery 200 has a plurality of secondary batteries. These secondary batteries are connected in series to form a battery stack. The SOC of this battery stack corresponds to the SOC of battery 200. The secondary batteries may be solid-state batteries, lithium-ion secondary batteries, nickel-metal hydride secondary batteries, organic radical batteries, or the like.

[0020] The power conversion device 300 performs power conversion between the battery 200 and the motor 400. The power conversion device 300 converts DC power from the battery 200 into AC power. The power conversion device 300 converts AC power generated by power generation (regeneration) by the motor 400 into DC power.

[0021] The motor 400 is connected to an axle of the electric vehicle (not shown). The rotational energy (power) of the motor 400 is transmitted to the running wheels of the electric vehicle via the axle. Conversely, the rotational energy of the running wheels is transmitted to the motor 400 via the axle.

[0022] The motor 400 is powered by AC power supplied from the power converter 300. This provides propulsion force to the running wheels. The motor 400 also regenerates power using rotational energy transmitted from the running wheels. The regenerated AC power is converted into DC power by the power converter 300. This DC power is supplied to the battery 200 and various electrical loads mounted on the electric vehicle.

[0023] <Power Conversion Apparatus> Next, the power conversion apparatus 300 will be described. The power conversion apparatus 300 has a power conversion circuit 500 and a case 600. The power conversion circuit 500 has the components shown in Fig. 1. The case 600 has the components shown in Fig. 2.

[0024] 3 and 4, the components of the power conversion circuit 500 are housed in a case 600. The case 600 is provided with a refrigerant passage 700 through which a refrigerant passes. The refrigerant passing through this refrigerant passage 700 suppresses a rise in temperature of the power conversion circuit 500. The case 600 corresponds to a cooler.

[0025] <Power Conversion Circuit> The power conversion circuit 500 includes an inverter 510. The inverter 510 converts DC power from the battery 200 into AC power. This AC power is supplied to the motor 400. The inverter 510 also converts AC power generated by the motor 400 into DC power. This DC power is supplied to the battery 200. The power conversion circuit 500 may also include a converter that steps up or steps down the input voltage and outputs it.

[0026] The power conversion circuit 500 has an N bus bar 501 and a P bus bar 502. The battery 200 is connected to the N bus bar 501 and the P bus bar 502. The N bus bar 501 is connected to the negative electrode of the battery 200. The P bus bar 502 is connected to the positive electrode of the battery 200.

[0027] The power conversion circuit 500 also has a U-phase bus bar 503, a V-phase bus bar 504, and a W-phase bus bar 505. The inverter 510 and the motor 400 are electrically connected via the U-phase bus bar 503, the V-phase bus bar 504, and the W-phase bus bar 505. In Fig. 1, the connection portions of the various bus bars are indicated by white circles. These connection portions are electrically connected by, for example, bolts or welding.

[0028] <Inverter> The inverter 510 has a smoothing capacitor 520 and a switch group 530. The smoothing capacitor 520 and the switch group 530 are electrically connected to an N bus bar 501 and a P bus bar 502.

[0029] The smoothing capacitor 520 is housed in a capacitor case 521, which is shown schematically in FIG. 3. The capacitor case 521 is made of an insulating resin material. The N bus bar 501 and a portion of the P bus bar 502 are housed in the capacitor case 521. The capacitor case 521 is fixed to the case 600.

[0030] The switch group 530 includes a U-phase switch module 531, a V-phase switch module 532, and a W-phase switch module 533. These three-phase switch modules have a high-side switch 541 and a low-side switch 542. The three-phase switch module also has a high-side diode 541a and a low-side diode 542a.

[0031] The switches and diodes included in the three-phase switch module are housed in a switch case 543, which is shown schematically in Figures 3 and 4. The switch case 543 is made of an insulating resin material. In this embodiment, the switches and diodes included in the three-phase switch module are housed in one switch case 543. Of course, it is also possible to employ a configuration in which the switches and diodes included in the three-phase switch module are housed individually in three switch cases 543.

[0032] In this embodiment, n-channel IGBTs are used as the high-side switch 541 and the low-side switch 542. As shown in Fig. 1, the emitter electrode of the high-side switch 541 and the collector electrode of the low-side switch 542 are connected together, thereby connecting the high-side switch 541 and the low-side switch 542 in series.

[0033] The cathode electrode of the high-side diode 541a is connected to the collector electrode of the high-side switch 541. The anode electrode of the high-side diode 541a is connected to the emitter electrode of the high-side switch 541. As a result, the high-side diode 541a is connected in anti-parallel to the high-side switch 541.

[0034] Similarly, the cathode electrode of the low-side diode 542a is connected to the collector electrode of the low-side switch 542. The anode electrode of the low-side diode 542a is connected to the emitter electrode of the low-side switch 542. As a result, the low-side diode 542a is connected in anti-parallel to the low-side switch 542.

[0035] As described above, the switch is housed in switch case 543. Exposed from switch case 543 are a tip of collector terminal 540a connected to the collector electrode of high-side switch 541 and a tip of output terminal 540b connected to the midpoint between high-side switch 541 and low-side switch 542. Also exposed from switch case 543 are a tip of emitter terminal 540c connected to the emitter electrode of low-side switch 542 and a tip of gate terminal 540d connected to the gate electrodes of high-side switch 541 and low-side switch 542.

[0036] 1, the collector terminal 540a is connected to the P bus bar 502. The emitter terminal 540c is connected to the N bus bar 501. With this electrical connection, the high-side switch 541 and the low-side switch 542 are connected in series in this order from the P bus bar 502 to the N bus bar 501.

[0037] A U-phase bus bar 503 is connected to an output terminal 540b of the U-phase switch module 531. A V-phase bus bar 504 is connected to an output terminal 540b of the V-phase switch module 532. A W-phase bus bar 505 is connected to an output terminal 540b of the W-phase switch module 533.

[0038] The motor 400 has a U-phase stator coil, a V-phase stator coil, and a W-phase stator coil. A U-phase bus bar 503 is electrically connected to the U-phase stator coil. A V-phase bus bar 504 is electrically connected to the V-phase stator coil. A W-phase bus bar 505 is electrically connected to the W-phase stator coil. This electrically connects the inverter 510 and the motor 400.

[0039] The gate terminals 540d of the high-side switches 541 and low-side switches 542 included in the U-phase switch modules 531 to W-phase switch modules 533 are connected to the gate driver.

[0040] The gate driver, together with some of the multiple ECUs described above, is included in the circuit board 550 shown in FIG. 1. The ECU generates a control signal and outputs it to the gate driver. The gate driver amplifies the control signal and outputs it to gate terminal 540d. This allows the high-side switch 541 and low-side switch 542 to be controlled to open or close by the ECU. Note that the board on which the gate driver is mounted and the board on which the ECU is mounted may be separate.

[0041] The ECU generates a pulse signal as a control signal. The ECU adjusts the on-duty ratio and frequency of this pulse signal. The on-duty ratio and frequency are determined based on the outputs of various sensors.

[0042] When motor 400 is powered, a control signal is output from the ECU to PWM-control high-side switch 541 and low-side switch 542 of the three-phase switch module. This generates a three-phase AC current in power conversion circuit 500. This three-phase AC current is input to three-phase stator coils. This generates a three-phase rotating magnetic field in the three-phase stator coils. The interaction between this three-phase rotating magnetic field and the magnetic field generated by the rotor of motor 400 generates a rotational torque in the rotor.

[0043] When the motor 400 generates (regenerates) electricity using the rotational energy of the running wheels, the ECU, for example, stops outputting the control signal. As a result, the AC power generated by the power generation passes through the diodes of the three-phase switch module. As a result, the AC power is converted into DC power.

[0044] The types of switch elements included in the U-phase switch module 531 to W-phase switch module 533 are not particularly limited, and MOSFETs, for example, can be used. The switches, diodes, and other semiconductor elements included in these three-phase switch modules can be manufactured using semiconductors such as Si and wide-gap semiconductors such as SiC. The constituent materials of the semiconductor elements are not particularly limited.

[0045] Furthermore, the number of high-side switches 541 and low-side switches 542 included in the three-phase switch module is not limited to one. At least one of the three-phase switch modules may include a plurality of high-side switches 541 connected in parallel and a plurality of low-side switches 542 connected in parallel. The number of switches connected in parallel can be determined based on the rated current of the switches and the amount of current that can be passed through the power conversion circuit 500, etc.

[0046] <Case> The case 600 is made of a high-permeability material that has a higher magnetic permeability than air. Specifically, the case 600 is made of a metal material such as alumina or iron. The case 600 houses the capacitor case 521 and the switch case 543. The case 600 houses the components of the power conversion circuit 500 shown in FIG. 1 . The case 600 also houses a current sensor (not shown) and the like.

[0047] As shown schematically in FIGS. 2 to 4, the case 600 has, as its major components, a first case 610, a second case 620, and a third case 630. The first case 610 and the third case 630 are arranged side by side in the Z direction with the second case 620 interposed therebetween. The first case 610 and the second case 620 are connected via a seal, and the second case 620 and the third case 630 are connected via a seal. This forms a refrigerant passage 700 inside the case 600. The refrigerant passage 700 is mainly defined by the walls of the first case 610, the second case 620, and the third case 630. In addition to the case 600, FIGS. 2 and 3 also show a capacitor case 521 and a switch case 543.

[0048] The first case 610 has a first upper surface 610a and a first lower surface 610b aligned in the Z direction. The second case 620 has a second upper surface 620a and a second lower surface 620b aligned in the Z direction. The third case 630 has a third upper surface 630a and a third lower surface 630b aligned in the Z direction.

[0049] The first case 610 and the second case 620 are connected in a manner that the first upper surface 610a and the second lower surface 620b face each other in the Z direction. The second case 620 and the third case 630 are connected in a manner that the second upper surface 620a and the third lower surface 630b face each other in the Z direction.

[0050] 3 and 4 , the first upper surface 610a and the second lower surface 620b are partially undulating in the Z direction. Furthermore, the third lower surface 630b is along a plane perpendicular to the Z direction, but the second upper surface 620a is partially undulating in the Z direction. The first upper surface 610a and the second lower surface 620b are partially in contact with each other, and these two surfaces form a portion of the refrigerant passage 700. The second upper surface 620a and the third lower surface 630b are partially in contact with each other, and these two surfaces form a portion of the refrigerant passage 700.

[0051] Further, a through hole penetrating second upper surface 620a and second lower surface 620b is formed in second case 620. This through hole also constitutes part of refrigerant passage 700. This through hole communicates between the space defined by first upper surface 610a and second lower surface 620b and the space defined by second upper surface 620a and third lower surface 630b.

[0052] As shown in FIG. 5 , an input pipe 701 and a discharge pipe 702 are connected to a refrigerant passage 700. The input pipe 701 and the discharge pipe 702 are connected to a pump (not shown). The refrigerant that flows from the input pipe 701 into the refrigerant passage 700 exchanges heat with the components of the power conversion circuit 500 housed in the case 600. The refrigerant that has exchanged heat is returned to the pump via the discharge pipe 702. The temperature of the refrigerant returned to the pump is lowered by a cooler such as a radiator. The lowered temperature refrigerant is supplied back to the input pipe 701. The input pipe 701 is formed by the second case 620, and the discharge pipe 702 is formed by the third case 630. However, the input pipe 701 and the discharge pipe 702 may be formed separately from the case 600.

[0053] <Refrigerant Passage> The refrigerant passage 700 has a first refrigerant passage 710, a second refrigerant passage 720, a third refrigerant passage 730, and a fourth refrigerant passage 740. The refrigerant passage 700 also has a first communication hole 751, a second communication hole 752, and a third communication hole 753.

[0054] The first upper surface 610a and the second lower surface 620b define the first refrigerant passage 710, the second refrigerant passage 720, and the fourth refrigerant passage 740. The first communication hole 751 is also defined by the first upper surface 610a and the second lower surface 620b.

[0055] The third refrigerant passage 730 is a space defined by the second upper surface 620a and the third lower surface 620b. The first communication hole 751 and the second communication hole 752 are through holes that penetrate the second upper surface 620a and the second lower surface 620b of the second case 620.

[0056] An input pipe 701 is connected to a first refrigerant passage 710. The first refrigerant passage 710 and the second refrigerant passage 720 communicate with each other via a first communication hole 751. The second refrigerant passage 720 and the third refrigerant passage 730 communicate with each other via a second communication hole 752. The third refrigerant passage 730 and the fourth refrigerant passage 740 communicate with each other via a third communication hole 753. An exhaust pipe 702 is connected to the fourth refrigerant passage 740.

[0057] Due to this mechanical configuration, the refrigerant supplied to the input pipe 701 passes through the first refrigerant passage 710, the first communication hole 751, the second refrigerant passage 720, the second communication hole 752, the third refrigerant passage 730, the third communication hole 753, and the fourth refrigerant passage 740 in that order, before being discharged into the discharge pipe 702.

[0058] The first refrigerant passage 710 is located upstream in the direction of refrigerant flow, and the fourth refrigerant passage 740 is located downstream. As the refrigerant travels from upstream to downstream, it exchanges heat with various components of the power conversion circuit 500 housed in the case 600. Therefore, the temperature of the refrigerant is higher downstream than upstream.

[0059] The capacitor case 521 is provided on the second upper surface 620a of the second case 620. The first refrigerant passage 710 and the capacitor case 521 are aligned in the Z direction. The capacitor case 521 is pressed against the second case 620 by bolts or the like. This allows active thermal conduction between the capacitor case 521 and the second case 620. The rise in temperature of the smoothing capacitor 520 housed in the capacitor case 521 is suppressed mainly by the refrigerant passing through the first refrigerant passage 710. The capacitor case 521 corresponds to the first component. The first refrigerant passage 710 corresponds to the first cooling flow path.

[0060] The refrigerant that has exchanged heat with smoothing capacitor 520 flows from first refrigerant passage 710 to second refrigerant passage 720. This refrigerant flows from second refrigerant passage 720 to third refrigerant passage 730. In this way, second refrigerant passage 720 functions to relay between first refrigerant passage 710 and third refrigerant passage 730. Second refrigerant passage 720 corresponds to a communication flow path.

[0061] A switch case 543 is provided on the third upper surface 630a of the third case 630. The third refrigerant passage 730 and the switch case 543 are aligned in the Z direction. The switch case 543 is pressed against the third case 630 by a fixing member (not shown). This allows active thermal conduction between the switch case 543 and the third case 630. The temperature rise of the switch group 530 housed in the switch case 543 is suppressed mainly by the refrigerant passing through the third refrigerant passage 730. The switch case 543 corresponds to the second component. The third refrigerant passage 730 corresponds to the second cooling flow path.

[0062] The refrigerant that has exchanged heat with switch group 530 flows from third refrigerant passage 730 to fourth refrigerant passage 740. This refrigerant is returned to the pump. The temperature of this refrigerant is lowered by a cooler and is supplied to first refrigerant passage 710 again.

[0063] <Refrigerant Flow Speed> When the refrigerant passes through the refrigerant passage 700, the flow direction changes depending on the shape of the refrigerant passage 700. This causes a pressure loss, which reduces the refrigerant flow speed. As a result, there is a concern that the cooling effect of the refrigerant on the power conversion circuit 500 may be reduced.

[0064] <Refrigerant Passage> In order to solve this problem, the present disclosure has devised a shape for the refrigerant passage 700. The refrigerant passage 700 will be described in detail below.

[0065] 5, the input pipe 701, the first refrigerant passage 710, the second refrigerant passage 720, and the third refrigerant passage 730 are aligned in order in the Y direction. The fourth refrigerant passage 740 and the second refrigerant passage 720 are aligned in the X direction.

[0066] In the Z direction, the first refrigerant passage 710 is located below the second refrigerant passage 720, the third refrigerant passage 730, and the fourth refrigerant passage 740. The second refrigerant passage 720 is located between the first refrigerant passage 710 and the third refrigerant passage 730 in the Z direction. The third refrigerant passage 730 is located above the first refrigerant passage 710, the second refrigerant passage 720, and the fourth refrigerant passage 740 in the Z direction. The position of the fourth refrigerant passage 740 in the Z direction is the same as the position of the second refrigerant passage 720 in the Z direction.

[0067] The first refrigerant passage 710 and the second refrigerant passage 720 are not aligned in the Z direction, but are aligned in the Y direction. The second refrigerant passage 720 and the third refrigerant passage 730 are aligned in the Z direction. The third refrigerant passage 730 and the fourth refrigerant passage 740 are aligned in the Z direction. Furthermore, the fourth refrigerant passage 740 and the discharge pipe 702 are aligned in the Z direction.

[0068] A refrigerant flows through the refrigerant passage 700, but because the refrigerant is a fluid, its flow direction is not uniquely determined. However, for ease of explanation, in this disclosure, the direction in which the refrigerant is expected to flow will be referred to as the refrigerant flow direction. When the refrigerant passage 700 is filled with refrigerant, the refrigerant flowing through the refrigerant passage 700 is expected to flow mainly along the extension direction of the wall surfaces that define the refrigerant passage 700. Of course, this refrigerant flow direction is the same for the input pipe 701 and the discharge pipe 702.

[0069] The input pipe 701 extends in the Y direction. Therefore, the flow direction of the refrigerant that flows into this input pipe 701 is also the Y direction. The refrigerant flowing in the Y direction flows into the first refrigerant passage 710.

[0070] The first refrigerant passage 710 extends in the Y direction. The first refrigerant passage 710 is short in the Z direction but wide in the X direction. The width of the first refrigerant passage 710 in the X direction gradually widens, remains constant, and then gradually narrows as it moves from the input pipe 701 to the first communicating hole 751. In this way, the shape of the first refrigerant passage 710 changes as it moves from the input pipe 701 to the first communicating hole 751. However, the flow path cross-sectional area of ​​the first refrigerant passage is constant.

[0071] The refrigerant flowing through the first refrigerant passage 710 flows mainly in the Y direction. At the same time, as the refrigerant flowing through the first refrigerant passage 710 travels from the input pipe 701 toward the second refrigerant passage 720, it flows away from the input pipe 701 in the X direction, and after reaching a constant flow, it flows gradually toward the first communicating hole 751 in the X direction.

[0072] The refrigerant flowing in the Y and X directions flows into the second refrigerant passage 720 through the first communication holes 751. The shape of the first communication holes 751 is the same as the shape of the first refrigerant passage 710 on the second refrigerant passage 720 side.

[0073] 3 and 5 , the length of the first communication hole 751 in the Y direction is shorter than its lengths in the X and Z directions. The first communication hole 751 opens to the wall surface that defines the first refrigerant passage 710 and the wall surface that defines the second refrigerant passage 720, and these two openings have the same shape. In this embodiment, the positions of these two openings in the X and Z directions are the same.

[0074] Due to this configuration, the flow direction of the refrigerant flowing through the first communication hole 751 is unlikely to be corrected by the wall surfaces that form the first communication hole 751. Refrigerant flowing in the Y direction and X direction described above flows into the second refrigerant passage 720. Note that the first communication hole 751 is merely defined for convenience to distinguish the first refrigerant passage 710 and the second refrigerant passage 720, and the first refrigerant passage 710 and the second refrigerant passage 720 may also be configured to be continuously connected. The first communication hole 751 corresponds to an inlet.

[0075] The second refrigerant passage 720 extends in both the Y direction and the Z direction. The flow path cross-sectional area of ​​the second refrigerant passage 720 gradually narrows in the Y direction as it moves away from the first refrigerant passage 710. The width of the second refrigerant passage 720 in the X direction gradually narrows as it moves from the first refrigerant passage 710 toward the third refrigerant passage 730.

[0076] Due to this shape, the refrigerant flowing through the second refrigerant passage 720 flows in the Y direction, the Z direction, and the X direction. The refrigerant flowing through the second refrigerant passage 720 flows in the Y direction while resisting gravity. At the same time, as the refrigerant flowing through the second refrigerant passage 720 moves from the first communication hole 751 to the second communication hole 752 in the Y direction and the Z direction, it gradually moves closer to the second communication hole 752 in the X direction.

[0077] The refrigerant flowing in the Y, Z, and X directions flows into the second communication hole 752. The second communication hole 752 extends in the Z direction. The second communication hole 752 is aligned with the switch case 543 in the Z direction. The second communication hole 752 opens into the wall surface defining the second refrigerant passage 720 and the wall surface defining the third refrigerant passage 730, and these two opening shapes are identical. The positions of these two openings in the X and Y directions are identical. Therefore, the flow direction of the refrigerant that flows from the second refrigerant passage 720 into the second communication hole 752 is changed from the Y, Z, and X directions to mainly the Z direction. The refrigerant flowing in the Z direction flows up into the third refrigerant passage 730. The second communication hole 752 corresponds to an outlet.

[0078] The third refrigerant passage 730 extends in the X direction. The flow path cross-sectional area of ​​the third refrigerant passage 730 is constant. The third refrigerant passage 730 is short in the Z direction but wide in the Y direction. The width of the third refrigerant passage 730 in the Y direction is constant. The opening locations of the second communication holes 752 and the third communication holes 753 in the third refrigerant passage 730 are separated in the X direction and located at the same position in the Y direction. Therefore, the refrigerant flowing through the third refrigerant passage 730 flows mainly in the X direction. The refrigerant flowing through this third refrigerant passage 730 in the X direction flows down into the third communication holes 753.

[0079] The third communication hole 753 extends in the Z direction. The third communication hole 753 opens to the wall surface that defines the third refrigerant passage 730 and the wall surface that defines the fourth refrigerant passage 740. These two openings have the same shape and are positioned in the same way in the X and Y directions.

[0080] The fourth refrigerant passage 740 extends in the Z direction. The refrigerant flows down into this fourth refrigerant passage 740 from the third communication hole 753. The discharge pipe 702 is connected to the fourth refrigerant passage 740. The refrigerant that flows into the fourth refrigerant passage 740 flows into the discharge pipe 702. The refrigerant that flows into the discharge pipe 702 is returned to the pump as described above. Note that the refrigerant may be made to flow in an annular buffer space between the discharge pipe 702 and the pump. This buffer space is defined in the case 600.

[0081] <Second Refrigerant Path> As described above, the first refrigerant path 710 and the third refrigerant path 730 are spaced apart in the Y direction and also in the Z direction. The reason for this spaced apart in the Z direction is that the smoothing capacitor 520 is larger than the switch group 530. This space is intended to efficiently cool both the smoothing capacitor 520 and the switch group 530 while minimizing an increase in the size of the case 600. Due to these circumstances, the first refrigerant path 710 and the third refrigerant path 730 are spaced apart in the Z direction, and the second refrigerant path 720, which connects the first refrigerant path 710 and the third refrigerant path 730, extends in the Z direction. It is desirable to find a way to prevent a decrease in the flow speed of the refrigerant flowing through the second refrigerant path 720 against gravity.

[0082] As described above, second refrigerant passage 720 is defined by first upper surface 610a of first case 610 and second lower surface 620b of second case 620. In the following, to simplify the description of second refrigerant passage 720, the wall surfaces defining second refrigerant passage 720 will be divided into six surfaces. That is, the wall surfaces defining second refrigerant passage 720 are divided into a second left surface 721 and a second right surface 722 that are spaced apart in the X direction, a second front surface 723 and a second rear surface 724 that are spaced apart in the Y direction, and a second top surface 725 and a second bottom surface 726 that are spaced apart in the Z direction.

[0083] The second left surface 721 is farther from the fourth refrigerant passage 740 in the X direction than the second right surface 722. The second front surface 723 is located closer to the first refrigerant passage 710 in the Y direction than the second rear surface 724. The second top surface 725 is located higher in the Z direction than the second bottom surface 726.

[0084] The second left surface 721, the second rear surface 724, the second right surface 722, and the second front surface 723 are connected in this order to form a second annular surface 727. An opening located on the upper side of this second annular surface 727 in the Z direction is closed by a second top surface 725, and an opening located on the lower side in the Z direction is closed by a second bottom surface 726. The second top surface 725, the second bottom surface 726, and the second annular surface 727 correspond to connecting surfaces.

[0085] A first communication hole 751 opens on the second bottom surface 726 side of the second front surface 723. A second communication hole 752 opens on the second top surface 725.

[0086] As shown in Figures 3 and 4, the second bottom surface 726 partially protrudes toward the second top surface 725. Breaking down this partially protruded portion into more detail, the second bottom surface 726 includes a first horizontal surface 726a and a second horizontal surface 726b spaced apart in the X direction, and a sloped surface 726c and a back surface 726d spaced apart in the Y direction. The protruded portion of the second bottom surface 726 also includes a top surface 726e located above these four surfaces in the Z direction. The first horizontal surface 726a, the back surface 726d, the second horizontal surface 726b, and the sloped surface 726c are connected in order to form a ring. Of the two openings defined by the four surfaces forming this ring, the opening located above in the Z direction is closed by the top surface 726e. The five surfaces forming the partially raised portion of the second bottom surface 726 face, but are spaced apart from, the other five surfaces other than the second bottom surface 726 that define the second refrigerant passage 720 .

[0087] That is, the first lateral surface 726a faces the second left surface 721 while being spaced apart in the X direction. The second lateral surface 726b faces the second right surface 722 while being spaced apart in the X direction. The inclined surface 726c faces the second front surface 723 while being spaced apart in the Y direction. The rear surface 726d faces the second rear surface 724 while being spaced apart in the Y direction. The top bottom surface 726e faces the second top surface 725 while being spaced apart in the Z direction. Furthermore, between the top bottom surface 726e and the second top surface 725, the second left surface 721 and the second right surface 722 face each other while being spaced apart, and the second front surface 723 and the second rear surface 724 face each other while being spaced apart. These surfaces facing each other while being spaced apart form a space through which the refrigerant flows.

[0088] 4 , the second left surface 721 and the second right surface 722 extend in the Z direction. However, the second right surface 722 is inclined more greatly with respect to the Z direction than the second left surface 721. The distance between the second left surface 721 and the second right surface 722 in the X direction gradually decreases from the second bottom surface 726 toward the second top surface 725 in the Z direction.

[0089] Due to this configuration, as shown in FIG. 5 , the width of the second refrigerant passage 720 in the X direction gradually narrows from the first communication hole 751 toward the second communication hole 752 .

[0090] 3 , the second front surface 723 and the second rear surface 724 extend in the Z direction. However, the second front surface 723 is inclined more greatly with respect to the Z direction than the second rear surface 724. The distance between the second front surface 723 and the second rear surface 724 in the Y direction gradually decreases from the second bottom surface 726 toward the second top surface 725 in the Z direction.

[0091] The slope 726c of the partially raised portion of the second bottom surface 726 and the back surface 726d extend in the Z direction. However, the slope 726c is more inclined with respect to the Z direction than the back surface 726d. The inclination angle of the slope 726c is uniform.

[0092] The distance in the Y direction between the inclined surface 726c and the back surface 726d gradually decreases in the Z direction from the second bottom surface 726 toward the second top surface 725. In other words, the inclined surface 726c is inclined such that the distance in the Z direction between the inclined surface 726c and the second communicating hole 752 gradually decreases as the inclined surface 726c approaches the second communicating hole 752 from the first communicating hole 751 in the Y direction.

[0093] 3, an inclined space 720a, which is located between the inclined surface 726c of the second refrigerant passage 720 and the second front surface 723, and between the second left surface 721 and the second right surface 722, extends in the Y direction and is inclined with respect to the Z direction. The width of the inclined space 720a in the X direction gradually narrows from the first communication hole 751 to the second communication hole 752.

[0094] As shown in FIG. 3 , the first communication hole 751 and the inclined surface 726c face each other in the Y direction. Therefore, the refrigerant that flows into the second refrigerant passage 720 from the first communication hole 751 first flows through the inclined space 720a. The refrigerant that flows up the inclined surface 726c flows into the upper space 720b, which is located between the bottom upper surface 726e and the second top surface 725 in the Z direction and is shown surrounded by a dashed line in FIG. 3 . This upper space 720b is aligned with the second communication hole 752 in the Z direction. The upper space 720b is also aligned with the rear space 720c, which is located between the back surface 726d and the second rear surface 724 in the Y direction and is also shown surrounded by a dashed line in FIG. 3 . Therefore, some of the refrigerant that flows into the upper space 720b also flows into the rear space 720c. The upper space 720b is aligned with the second communication hole 752 in the Z direction.

[0095] The refrigerant flowing up from the inclined space 720a to the upper space 720b flows into the second communication hole 752 that opens to the second top surface 725. The refrigerant flowing from the upper space 720b to the rear space 720c then changes direction at the wall surface that forms the space 720c and flows back into the upper space 720b. The refrigerant in both the inclined space 720a and the rear space 720c flows into the upper space 720b and then flows up into the third refrigerant passage 730 via the second communication hole 752.

[0096] Horizontal spaces are defined between the second left surface 721 and the first horizontal surface 726a, and between the second right surface 722 and the second horizontal surface 726b. The inclined space 720a and the rear space 720c are connected via these horizontal spaces. A portion of the refrigerant that flows into the inclined space 720a from the first communication hole 751 flows into the upper space 720b via these horizontal spaces.

[0097] Furthermore, although not shown in the drawings as the shape is not particularly limited, this inclined space 720a may be provided with a flow straightening plate for adjusting the flow direction of the refrigerant.

[0098] 3 and 4 , the second communication hole 752 extends in the Z direction. The second communication hole 752 opens to the second top surface 725 and also opens to a region of the second upper surface 620a that defines the third refrigerant passage 730. The two openings of the second communication hole 752 have the same shape.

[0099] As shown in FIG. 6, the opening shape of the second communication hole 752 is defined by a left edge 752a and a right edge 752b spaced apart in the X direction, and a front edge 752c and a rear edge 752d spaced apart in the Y direction.

[0100] The left edge 752a corresponds to the first edge, the right edge 752b corresponds to the second edge, the front edge 752c corresponds to the third edge, and the rear edge 752d corresponds to the fourth edge.

[0101] The left edge 752a is farther away from the fourth refrigerant passage 740 in the X direction than the right edge 752b. The front edge 752c is located closer to the first refrigerant passage 710 in the Y direction than the rear edge 752d. The left edge 752a, the rear edge 752d, the right edge 752b, and the front edge 752c are connected in order to form the opening of the annular second communication hole 752. The opening of the second communication hole 752 is longer in the Y direction than in the X direction.

[0102] The front edge 752c and the rear edge 752d extend in the X direction. The rear edge 752d is shorter in length in the X direction than the front edge 752c.

[0103] The left edge 752a extends in the Y direction. The right edge 752b extends in a direction inclined relative to the Y direction. The right edge 752b is inclined such that the distance between the right edge 752b and the left edge 752a in the X direction gradually increases from the rear edge 752d to the front edge 752c in the Y direction.

[0104] Due to this opening shape, the refrigerant that flows up in the Z direction through the second communication hole 752 and flows out into the third refrigerant passage 730 flows more in the X direction than the Y direction, as shown by the solid arrow in Fig. 6. The refrigerant that flows up into the third refrigerant passage 730 flows in the third refrigerant passage 730 toward the third communication hole 753 that is aligned with but spaced apart from the second communication hole 752 in the X direction.

[0105] The opening shape of the second communication hole 752 on the second upper surface 620a may be trapezoidal as described above, or may be triangular.

[0106] <Third Refrigerant Passage> As described above, third refrigerant passage 730 is defined by second upper surface 620a of second case 620 and third lower surface 630b of third case 630. In the following, to simplify the description of third refrigerant passage 730, the wall surfaces defining third refrigerant passage 730 are divided into six surfaces. That is, the wall surfaces defining third refrigerant passage 730 are divided into a third left surface 731 and a third right surface 732 that are spaced apart from each other in the X direction, a third front surface 733 and a third rear surface 734 that are spaced apart from each other in the Y direction, and a third top surface 735 and a third bottom surface 736 that are spaced apart from each other in the Z direction.

[0107] The third left surface 731 is farther from the fourth refrigerant passage 740 in the X direction than the third right surface 732. The third front surface 733 is located closer to the first refrigerant passage 710 in the Y direction than the third rear surface 734. The third top surface 735 is located higher than the third bottom surface 736 in the Z direction.

[0108] The third left surface 731, the third rear surface 734, the third right surface 732, and the third front surface 733 are connected in this order to form a third annular surface 737. An opening located on the upper side of the third annular surface 737 in the Z direction is closed by a third top surface 735, and an opening located on the lower side of the third annular surface 737 in the Z direction is closed by a third bottom surface 736.

[0109] A second communication hole 752 opens on the third left surface 731 side of the third bottom surface 736. A third communication hole 753 opens on the third right surface 732 side of the third bottom surface 736. The opening of the second communication hole 752 and the opening of the third communication hole 753 are spaced apart in the X direction and are aligned side by side.

[0110] <Heat Dissipation Fins> As shown in Figures 3 and 4, a plurality of heat dissipation fins 738 are formed on the third top surface 735. In Figure 6, these heat dissipation fins 738 are indicated by dashed lines. The heat dissipation fins 738 are arranged at intervals in a direction perpendicular to the Z direction. Some of the heat dissipation fins 738 are aligned with the second communication holes 752 in the Z direction.

[0111] <Effects> The first refrigerant passage 710 extending in the Y direction and the third refrigerant passage 730 extending in the X direction are spaced apart in the Y direction and the Z direction. The second refrigerant passage 720 connecting the first refrigerant passage 710 and the third refrigerant passage 730 extends in both the Y direction and the Z direction. The sloped surface 726c of the wall surface defining the second refrigerant passage 720 is inclined so that the distance between the second refrigerant passage 720 and the second refrigerant passage 752 in the Z direction gradually decreases as the distance approaches the first communication hole 751 toward the second communication hole 752 in the Y direction. The sloped surface 726c faces the first communication hole 751 connecting the first refrigerant passage 710 and the second refrigerant passage 720 in the Y direction. Furthermore, the opening shape of the second communication hole 752 connecting the second refrigerant passage 720 and the third refrigerant passage 730 is longer in the Y direction than in the X direction.

[0112] This allows the flow direction of the refrigerant flowing in the Y direction through the first refrigerant passage 710 to be converted to the Z direction and the X direction, and then flow into the third refrigerant passage 730 extending in the X direction. The shape of the inclined surface 726c prevents a decrease in the flow speed of the refrigerant due to collisions. The shape of the second communication hole 752 makes it easier for the refrigerant to flow into the third refrigerant passage 730 extending in the X direction. As a result, a decrease in the flow speed of the refrigerant is prevented.

[0113] The opening shape of the second communication hole 752 is defined by a left edge 752a and a right edge 752b that are spaced apart in the X direction, and a rear edge 752d and a front edge 752c that are spaced apart in the Y direction. The right edge 752b is inclined so that the distance between it and the left edge 752a in the X direction gradually increases from the rear edge 752d to the front edge 752c in the Y direction.

[0114] Therefore, the refrigerant that flows up from the second communication hole 752 to the third refrigerant passage 730 flows more in the X direction than in the Y direction. This refrigerant is more likely to flow in the X direction, which is the extension of the third refrigerant passage 730. In the third refrigerant passage 730, this refrigerant is more likely to flow toward the third communication hole 753.

[0115] Furthermore, the front edge portion 752c is located closer to the first refrigerant passage 710 in the Y direction than the rear edge portion 752d. That is, the front edge portion 752c is located closer to the condenser case 521 in the Y direction than the rear edge portion 752d.

[0116] The refrigerant that flows from the second communication hole 752 into the third refrigerant passage 730 is more likely to flow toward the front edge 752c in the Y direction than toward the rear edge 752d. The flow rate of the refrigerant flowing toward the front edge 752c is more likely to be faster than that toward the rear edge 752d. Therefore, the refrigerant flowing through the third refrigerant passage 730 is more likely to suppress a temperature rise in the condenser case 521 located on the front edge 752c side.

[0117] The cross-sectional area of ​​the second refrigerant passage 720 on the side of the inclined space 720a is narrower on the side of the second communication hole 752 than on the side of the first communication hole 751. This suppresses a decrease in the flow rate of the refrigerant flowing up the inclined space 720a against gravity.

[0118] In the second refrigerant passage 720, the inclined space 720a and the rear space 720c are aligned in the Y direction via the inclined surface 726c. The second rear surface 724 side of the upper space 720b, which communicates with the rear space 720c, is aligned in the Z direction with the second communication hole 752. The second communication hole 752 is aligned in the Z direction with the switch case 543.

[0119] This makes it easier for the switch case 543 to be cooled by the refrigerant on the second rear surface 724 side of the rear space 720c and the upper space 720b.

[0120] Some of the multiple heat dissipation fins 738 are aligned in the Z direction with the second communication holes 752. This makes it easier to suppress a temperature rise in the third case 630 in which the heat dissipation fins 738 are provided. As a result, it is easier to suppress a temperature rise in the switch case 543 provided in the third case 630.

[0121] Second Embodiment In this embodiment, differences from the first embodiment will be mainly described. Hereinafter, other embodiments will also be described, focusing on differences from the previously described embodiment. Configurations, actions, and effects that are not particularly described in other embodiments are the same as those in the previously described embodiment.

[0122] In this embodiment, as shown in FIG. 7, the right edge 752b is inclined so that the distance between it and the left edge 752a in the X direction gradually increases from the front edge 752c to the rear edge 752d in the Y direction.

[0123] As a result, the refrigerant flowing up from the second communication hole 752 to the third refrigerant passage 730 is more likely to flow toward the rear edge 752d in the Y direction than toward the front edge 752c. The flow rate of the refrigerant flowing toward the rear edge 752d is more likely to be faster than that toward the front edge 752c. As a result, the refrigerant flowing through the third refrigerant passage 730 is more likely to suppress temperature increases in the components of the power conversion circuit 500 located on the rear edge 752d side. Examples of such components include the U-phase bus bar 503, the V-phase bus bar 504, and the W-phase bus bar 505, as well as the current sensors provided thereon.

[0124] <Other Modifications> The disclosure of this specification 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 elements shown in the embodiments, and can be implemented in various modifications. The disclosure can be implemented in various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure encompasses embodiments in which parts and elements of the embodiments are omitted. The disclosure encompasses the substitution or combination of parts and elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. The disclosed technical scope is defined by the claims, and should be interpreted as including all modifications within the meaning and scope equivalent to the claims.

[0125] In the present embodiment, an example has been shown in which the power conversion device 300 is employed in the in-vehicle system 100 of an electric vehicle. However, the use of the power conversion device 300 is not limited to the above example. The power conversion device 300 can be appropriately employed in hybrid automobiles, trucks, drones, robots, home appliances, and the like.

[0126] In the present embodiment, the case 600 is shown as both housing and cooling the power conversion circuit 500. However, the two functions of housing and cooling may be separated. That is, the case 600 may simply house the power conversion circuit 500. A component separate from the case 600 may be configured as a cooler having a refrigerant passage 700 for cooling the power conversion circuit 500.

[0127] <Disclosure of Technical Ideas> This specification discloses multiple technical ideas described in the following multiple clauses. Some clauses may be described in a multiple dependent form, where the subsequent clause alternatively cites the preceding clause. Furthermore, some clauses may be described in a multiple dependent form, where the subsequent clause cites a clause in another multiple dependent form. These clauses described in multiple dependent form define multiple technical ideas.

[0128] <Technical Idea 1> A cooler including a communication channel (720) that communicates a first cooling channel (710) that cools a first component (521) included in a power conversion circuit (500) and a second cooling channel (730) that cools a second component (543) included in the power conversion circuit, wherein the first cooling channel extends in a longitudinal direction perpendicular to a vertical direction, the second cooling channel extends in a lateral direction perpendicular to the vertical direction and the longitudinal direction, and the second cooling channel is located above the first cooling channel in the vertical direction and is spaced apart from the first cooling channel in the longitudinal direction, The communicating flow path is partitioned by a connecting surface (725, 726, 727) that connects an inlet (751) through which the refrigerant that has flowed through the first cooling flow path flows, and an outlet (752) that is located above the inlet in the vertical direction and spaced apart in the vertical direction, and through which the refrigerant that has flowed into the inlet flows out to the second cooling flow path, and a part of the connecting surface is a slope (726c) whose vertical distance from the outlet gradually decreases as it approaches the outlet from the inlet in the vertical direction, and the slope and the inlet are aligned in the vertical direction, and the outlet is longer in the vertical direction than in the horizontal direction. <Technical Idea 2> The cooler according to Technical Idea 1, wherein the outlet is defined by a first edge (752a) and a second edge (752b) that are spaced apart in the horizontal direction and a third edge (752c) and a fourth edge (752d) that are spaced apart in the vertical direction, the second cooling flow path extends in a direction from the first edge toward the second edge in the horizontal direction, the third edge has a shorter length in the horizontal direction than the fourth edge, and the second edge is inclined such that a separation distance from the first edge in the horizontal direction gradually increases from the third edge toward the fourth edge in the vertical direction. <Technical Idea 3> The cooler according to Technical Idea 2, wherein the fourth edge is located closer to the first component in the vertical direction than the third edge.<Technical Idea 4> The cooler according to Technical Idea 1, wherein the outlet is defined by a first edge (752a) and a second edge (752b) that are spaced apart in the horizontal direction, and a third edge (752c) and a fourth edge (752d) that are spaced apart in the vertical direction, the second cooling flow path extends in a direction from the first edge toward the second edge in the horizontal direction, the fourth edge has a shorter length in the horizontal direction than the third edge, the second edge is inclined such that a separation distance from the first edge in the horizontal direction gradually increases from the fourth edge toward the third edge in the vertical direction, and the fourth edge is located closer to the first component in the vertical direction than the third edge. <Technical Idea 5> The cooler according to any one of Technical Ideas 1 to 4, wherein a flow path cross-sectional area of ​​the communicating flow path is narrower on the outlet side than on the inlet side. <Technical Idea 6> The cooler according to any one of Technical Ideas 1 to 5, wherein the communicating flow path has an inclined space (720a) inclined with respect to the vertical direction so that a distance from the outlet in the vertical direction gradually decreases as the communicating flow path approaches the inlet in the vertical direction, a rear space (720c) aligned with the inclined space in the vertical direction via the inclined surface, and an upper space (720b) ​​communicating the inclined space with the rear space and aligned with the outlet in the vertical direction. <Technical Idea 7> The cooler according to any one of Technical Ideas 1 to 6, wherein some of a plurality of heat dissipation fins (738) provided in the second cooling flow path are aligned with the outlet in the vertical direction. <Technical Idea 8> The cooler according to any one of Technical Ideas 1 to 7, which houses the power conversion circuit.<Technical Idea 9> A power conversion device having a power conversion circuit (500) and a cooler (600) that cools the power conversion circuit, wherein the power conversion circuit has a first component (521) and a second component (543), the cooler includes a first cooling channel (710) that cools the first component, a second cooling channel (730) that cools the second component, and a communication channel (720) that communicates the first cooling channel and the second cooling channel, the first cooling channel extending in a longitudinal direction perpendicular to a vertical direction, the second cooling channel extending in a lateral direction perpendicular to the vertical direction and the longitudinal direction, the second cooling channel being positioned above the first cooling channel in the vertical direction and spaced apart from the first cooling channel in the longitudinal direction, The communicating flow path is partitioned by a connecting surface (725, 726, 727) that connects an inlet (751) through which the refrigerant that has flowed through the first cooling flow path flows, and an outlet (752) that is located above the inlet in the vertical direction and spaced apart in the vertical direction, and through which the refrigerant that has flowed into the inlet flows out to the second cooling flow path, a part of the connecting surface is a slope (726c) whose vertical distance from the outlet gradually decreases as it approaches the inlet in the vertical direction, the slope and the inlet are aligned in the vertical direction, and the outlet is longer in the vertical direction than in the horizontal direction.

Claims

1. A cooler comprising a communication flow path (720) communicating a first cooling flow path (710) for cooling a first component (521) included in a power conversion circuit (500) and a second cooling flow path (730) for cooling a second component (543) included in the power conversion circuit, wherein the first cooling flow path extends in a longitudinal direction perpendicular to the vertical direction, the second cooling flow path extends in a transverse direction perpendicular to the vertical and longitudinal directions, the second cooling flow path is located above the first cooling flow path in the vertical direction and is spaced apart from the first cooling flow path in the longitudinal direction, and the communication flow path is partitioned by connecting surfaces (725, 726, 727) connecting an inlet (751) through which a refrigerant flowing through the first cooling flow path flows, and an outlet (752) located above the inlet in the vertical direction and spaced apart from the inlet in the longitudinal direction, through which the refrigerant flowing into the inlet flows out to the second cooling flow path, A cooler in which a portion of the connecting surface is a slope (726c) in which the vertical distance from the outlet gradually decreases as the distance approaches from the inlet to the outlet in the vertical direction, the slope and the inlet are aligned in the vertical direction, and the outlet is longer in the vertical direction than in the horizontal direction.

2. The cooler of claim 1, wherein the outlet is defined by a first edge (752a) and a second edge (752b) spaced apart in the horizontal direction, and a third edge (752c) and a fourth edge (752d) spaced apart in the vertical direction, the second cooling flow path extends in the horizontal direction from the first edge toward the second edge, the third edge has a shorter length in the horizontal direction than the fourth edge, and the second edge is inclined so that the distance between the second edge and the first edge in the horizontal direction gradually increases as it moves from the third edge toward the fourth edge in the vertical direction.

3. A cooler according to claim 2, wherein the fourth edge portion is located closer to the first component in the longitudinal direction than the third edge portion.

4. A cooler as described in claim 1, wherein the outlet is defined by a first edge (752a) and a second edge (752b) spaced apart in the horizontal direction, and a third edge (752c) and a fourth edge (752d) spaced apart in the vertical direction, the second cooling flow path extends in the horizontal direction from the first edge toward the second edge, the fourth edge has a shorter length in the horizontal direction than the third edge, the second edge is inclined so that the distance between the second edge and the first edge in the horizontal direction gradually increases as it moves from the fourth edge toward the third edge in the vertical direction, and the fourth edge is located closer to the first component in the vertical direction than the third edge.

5. A cooler according to claim 1 or 2, wherein the cross-sectional area of ​​the communication flow path is narrower on the outlet side than on the inlet side.

6. A cooler as described in claim 1 or claim 2, wherein the communicating flow path has an inclined space (720a) that is inclined with respect to the vertical direction so that the vertical distance from the outlet gradually decreases as the communicating flow path approaches the inlet in the vertical direction, a rear space (720c) that is aligned with the inclined space in the vertical direction via the slope, and an upper space (720b) ​​that communicates the inclined space with the rear space and is aligned with the outlet in the vertical direction.

7. A cooler according to claim 1 or claim 2, wherein some of the heat dissipation fins (738) provided in the second cooling flow path are aligned vertically with the outlet.

8. A cooler according to claim 1 or claim 2, which houses the power conversion circuit.

9. A power conversion device having a power conversion circuit (500) and a cooler (600) for cooling the power conversion circuit, wherein the power conversion circuit has a first component (521) and a second component (543), and the cooler comprises a first cooling flow path (710) for cooling the first component, a second cooling flow path (730) for cooling the second component, and a communication flow path (720) for communicating the first cooling flow path with the second cooling flow path, wherein the first cooling flow path extends in a vertical direction perpendicular to the vertical direction, and the second cooling flow path extends in a horizontal direction perpendicular to the vertical direction and the vertical direction, and the second cooling flow path is located above the first cooling flow path in the vertical direction and is spaced apart from the first cooling flow path in the vertical direction, The communicating flow path is partitioned by a connecting surface (725, 726, 727) that connects an inlet (751) through which the refrigerant that has flowed through the first cooling flow path flows, and an outlet (752) that is located above the inlet in the vertical direction and spaced apart in the vertical direction, and through which the refrigerant that has flowed into the inlet flows out to the second cooling flow path, a part of the connecting surface is a slope (726c) whose vertical distance from the outlet gradually decreases as it approaches the inlet in the vertical direction, the slope and the inlet are aligned in the vertical direction, and the outlet is longer in the vertical direction than in the horizontal direction.

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