Electric power converting device

Abstract

This electric power converting device comprises a semiconductor device which incorporates a semiconductor element, heat dissipating fins which are thermally connected to the semiconductor device via a heat conductive member, a refrigerant flow passage member inside which a refrigerant flow passage through which a refrigerant flows is formed, and which holds the heat dissipating fins in a liquid-tight manner so as to be capable of relative displacement, and pressure-applying members which are disposed between the heat dissipating fins and an inner peripheral surface of the refrigerant flow passage member that faces the heat dissipating fins, and which urge the heat dissipating fins toward the semiconductor device, wherein each pressure-applying member has a base portion which comes into contact with the tips of the heat dissipating fins, and an inclined portion which is formed inclined from the base portion along the flow direction of the refrigerant, and which extends to the inner peripheral surface.

Description

Power Conversion Device

[0001] The present invention relates to a power conversion device.

[0002] In a power conversion device in which a large number of semiconductor devices are arranged side by side, there is a demand for increased current, as well as for productivity and heat dissipation. For example, Patent Document 1 listed below discloses a configuration in which a frame that is easily elastically deformed is used to achieve compliance between arms of the semiconductor devices in order to achieve both productivity and heat dissipation.

[0003] Japanese Patent Application Laid-Open No. 2023-073861

[0004] In the technology described in Patent Document 1, when the water channel is formed by fastening both ends of the power converter with screws, deformation of the cover and frame causes significant warping of the water channel, resulting in gaps at the tips of the fins in the water channel and the generation of bypass flow. This leads to issues such as a decrease in heat transfer coefficient and insufficient surface pressure on the semiconductor device. Furthermore, tensile stress is generated in the formed-in-place gasket (FIPG) used to secure the components together.

[0005] The semiconductor device includes a semiconductor device incorporating a semiconductor element, a heat dissipation fin thermally connected to the semiconductor device via a heat conduction member, a refrigerant flow path member having a refrigerant flow path formed therein through which a refrigerant flows and keeping the heat dissipation fin liquid-tight so that it can be displaced relative to the semiconductor device, and a pressure member arranged between the heat dissipation fin and the inner surface of the refrigerant flow path member facing the heat dissipation fin, and urging the heat dissipation fin toward the semiconductor device, wherein the pressure member has a base portion abutting against the tip of the heat dissipation fin, and an inclined portion formed at an angle from the base portion along the flow direction of the refrigerant and extending to the inner surface.

[0006] It is possible to provide a power conversion device that is compact, has good heat dissipation properties, and is highly reliable.

[0007] An exploded perspective view of a cooling structure portion of a power conversion device according to one embodiment of the present invention. A cross-sectional view illustrating the cooling structure of a semiconductor device when viewed along the X-X cross section of Figure 1. A cross-sectional view illustrating the cooling structure of a semiconductor device when viewed along the Y-Y cross section of Figure 1. A diagram illustrating a pressure member according to one embodiment of the present invention. First modified example. Second modified example.

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and some omissions and simplifications have been made as appropriate for clarity of explanation. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0009] In order to facilitate understanding of the invention, the position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0010] (One embodiment and overall configuration) (FIGS. 1 to 3) In a power conversion device, a structure for cooling a semiconductor device 8 incorporating a semiconductor element is provided with a coolant channel member that forms a coolant channel 14 through which a coolant flows. The coolant channel member has a cover 2, a frame 3, and heat dissipation fins 4. The cover 2 is fastened to the frame 3, and the heat dissipation fins 4 are fitted into each of a plurality of through holes 3a in the frame 3.

[0011] The heat dissipating fins 4 are fixed by the frame 3 so that the fin portions are disposed within the coolant flow path 14. The heat dissipating fins 4 are held liquid-tight to the frame 3 by a seal member 9, but are movable relative to the frame 3.

[0012] If the refrigerant flowing through the refrigerant flow path 14 is a conductive refrigerant, such as an ethylene glycol aqueous solution, the semiconductor device 8 and the heat dissipation fin 4 must be insulated from each other, and therefore an insulating heat conduction member 7 is provided between the heat dissipation fin 4 and the semiconductor device 8.

[0013] The refrigerant flowing through the refrigerant flow path 14 is a non-conductive refrigerant, such as an insulating refrigerant such as ATF (Automatic Transmission Fluid), mineral oil, or synthetic hydrocarbon. In this case, a non-insulating heat-conducting member 7 with high thermal conductivity is provided between the heat-dissipating fins 4 and the semiconductor device 8. The semiconductor device 8 and the heat-dissipating fins 4 are at the same potential, and the heat-dissipating fins 4 are thermally connected to the semiconductor device 8 via the heat-conducting member 7, which replaces the insulating layer with low thermal conductivity that was previously provided, thereby reducing the thermal resistance from the heat-dissipating fins 4 to the semiconductor device 8.

[0014] The frame 3 may be made of metal or resin. The sealing member 9 may be a liquid sealing material such as a formed-in-place gasket (FIPG) or a flexible material such as an O-ring. This not only ensures liquid-tightness but also reduces tensile stress generated in the sealing member 9, thereby improving reliability. The liquid-tightness of the heat dissipation fins 4 relative to the frame 3 may be maintained by joining the heat dissipation fins 4 to the frame 3 by brazing, laser welding, or the like, without using the sealing member 9.

[0015] The thermal conduction member 7 is, for example, a TIM (Thermal Interface Material), which may be grease or gap filler, or may be an insulating material (grease, ceramic plate, etc.) or a conductive material (materials with high thermal conductivity such as carbon sheet, solder, sintering, metal sheet, etc.).

[0016] The pressure member 5 is a member that is disposed between the heat dissipation fins 4 and the inner peripheral surface of the refrigerant flow path member that faces the heat dissipation fins 4, and that urges the plurality of heat dissipation fins 4 toward the semiconductor devices 8. The pressure member 5 is provided at a position that faces each of the plurality of semiconductor devices 8, with the heat dissipation fins 4 interposed therebetween. The pressure member 5 has a plurality of fastening points (not shown) that are attached to the cover 2, and is fixed to the inside of the refrigerant flow path 14 at these fastening points by fastening members (not shown).

[0017] The pressure member 5 includes an inclined portion 11, a base portion 12, and a convex portion 13. The base portion 12 is a portion that abuts against the tip of the heat dissipation fin 4. The inclined portion 11 is formed at an angle from the base portion 12 along the refrigerant flow direction 6 and extends to the inner circumferential surface.

[0018] The protrusions 13 are formed at positions between adjacent heat dissipation fins 4 in the direction in which the semiconductor devices 8 are lined up, and protrude from and contact the frame 3. The cover 2 is fastened with screws at the fastening portions 2a at both ends thereof, so that the protrusions 13 come into contact with the frame 3, suppressing deflection or warping of the frame 3, and also ensuring surface pressure on the semiconductor devices 8 arranged side by side, thereby reducing the gaps at the tips of the heat dissipation fins 4, reducing bypass flow, and preventing a decrease in the heat transfer coefficient.

[0019] The inclined portion 11 has a first inclined portion 11a and a second inclined portion 11b. The first inclined portion 11a is formed so as to block the refrigerant flowing along the flow direction 6 (the X-X direction in FIG. 1 ). In this way, the pressure member 5 functions as a flow path control member, thereby improving the flow rate of the refrigerant before it flows into the heat dissipation fins 4. Furthermore, the pressure member 5 can simultaneously suppress bypass flow in the heat dissipation fins 4 and improve the flow rate of the heat dissipation fins 4, thereby improving heat dissipation performance. The second inclined portion 11b does not affect flow path control, but contributes to the ability of the pressure member 5 to follow the semiconductor device 8 and the heat dissipation fins 4.

[0020] As shown in Fig. 2, the refrigerant flow path member has an insulating member 10 that ensures insulation at the portion where the cover 2 abuts against the pressure member 5, but it may also be configured so that the cover 2 and the pressure member 5 abut without providing the insulating member 10. Also, the cover 2 itself may be an insulating member. When the cover 2 itself is an insulating member, the cover 2 is configured as a resin plate or a combination of resin and metal plates. This allows for both insulation and heat dissipation.

[0021] The protrusions 13 are provided at the contact points between the pressure member 5 and the insulating member 10, thereby contributing to improved positioning of the pressure member 5 in the planar direction. Furthermore, the protrusions 13 also function as fastening parts, making it possible to eliminate fastening parts that would conventionally be formed at these positions, thereby contributing to cost reduction.

[0022] The pressure members 5 are separate from the cover 2 and are deformable members. The pressure members 5 are, for example, leaf spring members. Each pressure member 5 is provided corresponding to each heat dissipation fin 4 and is biased against the heat dissipation fin 4 at the base 12. However, as shown in FIG. 3 , there is a difference in height between each semiconductor device 8, so that the heights of the pressure members 5 that come into contact with the heat dissipation fin 4 differ from each other.

[0023] The cover 2 and the frame 3 are fastened to each other at a fastening portion 2a provided outside the refrigerant flow path 14, and the pressure members 5 are not only formed in positions close to the fastening portion 2a but are also provided in positions away from the fastening portion 2a. For example, the pressure members 5 provided in positions closest to the fastening portion 2a are designated as the first pressure member 5a, the second pressure member 5b, and the third pressure member 5c, in that order.

[0024] The third pressure member 5c, which is located away from the fastening portion 2a, may have a lower surface pressure than the first pressure member 5a due to the fact that the center of the cover 2 is not fastened. However, in the present invention, the base 12 of the third pressure member 5c protrudes further from the heat dissipation fins 4 than the base 12 of the first pressure member 5a or the base 12 of the second pressure member 5b. This allows the third pressure member 5c to come into strong contact with the heat dissipation fins 4 in order, ensuring compliance with the semiconductor device 8 and the heat dissipation fins 4.

[0025] The pressure member 5 is divided at the center of the base 12 so as to correspond to each of two adjacent heat dissipation fins 4 (two adjacent semiconductor devices 8) in the direction in which the multiple heat dissipation fins 4 are arranged side by side. The configuration of the pressure member 5 is not limited to this, and the inclined portion 11 and the base 12 do not have to be connected to each other. Furthermore, the pressure member 5 may be configured so that only one pressure member 5 covering the tip of the heat dissipation fin 4 corresponds to each of the multiple heat dissipation fins 4 provided in the power conversion device. When the pressure member 5 is formed into an integrated shape by pressing or the like, improved installation ease and cost reduction can be achieved.

[0026] (Fig. 4) is a plan view of a pressure member 5 on which a convex portion 13 is formed, among the pressure members 5 divided at the center of the base portion 12. The pressure member 5 is formed as a single unit for each heat dissipation fin, and when viewed in plan, the inclined portions 11b are connected to each other by the convex portion 13, and multiple base portions 12 are formed to protrude in the planar direction from the inclined portions 11a.

[0027] (First Modification) (FIG. 5) When the insulating member 10 is provided between the pressure member 5 and the cover 2, the insulating member 10 has a first protruding portion 10a that protrudes toward the heat dissipation fins 4. The insulating member 10 also has a second protruding portion 10b that protrudes toward the frame 3.

[0028] The first protrusion 10a is formed above the heat dissipation fins 4 and protrudes toward the base 12 of the pressure member 5, thereby improving the fixation of the heat dissipation fins 4 and the semiconductor device 8 in the stacking direction. Furthermore, the first protrusion 10a is provided on the same line in a parallel direction as the screw fastening portions 2a (FIG. 3) on both ends, thereby reducing deflection of the cover 2 during fastening, improving heat dissipation and ensuring reliability. The first protrusion 10a does not need to come into contact with the pressure member 5.

[0029] The second protrusion 10b is provided at the end of the pressure member 5, thereby preventing the pressure member 5 from shifting in position in the planar direction, and improving the positioning ability of the pressure member 5.

[0030] (Second Modification) (FIG. 6) The second protrusion 10b may be inclined with respect to the flow direction 6 of the refrigerant flow path. This structure not only improves the positioning of the pressure member 5 in the planar direction, but also increases the flow rate of the refrigerant flowing toward the heat dissipation fins 4. When provided together with the first inclined portion 11a, it is possible to further improve heat dissipation.

[0031] According to the embodiment of the present invention described above, the following advantageous effects are achieved.

[0032] (1) A power conversion device includes a semiconductor device having a built-in semiconductor element, a heat dissipation fin 4 thermally connected to the semiconductor device 8 via a heat conduction member 7, a refrigerant flow path member having a refrigerant flow path 14 formed therein through which a refrigerant flows and liquid-tightly holding the heat dissipation fin 4 so as to be relatively displaceable, and a pressure member 5 disposed between the heat dissipation fin 4 and an inner peripheral surface of the refrigerant flow path member facing the heat dissipation fin 4 and biasing the heat dissipation fin 4 toward the semiconductor device 8, wherein the pressure member 5 has a base 12 abutting against the tip of the heat dissipation fin 4 and an inclined portion 11 formed at an angle from the base 12 along the refrigerant flow direction 6 and extending to the inner peripheral surface. This configuration makes it possible to provide a power conversion device that is compact, has good heat dissipation properties, and is highly reliable.

[0033] (2) The pressure members 5 face the semiconductor devices 8, respectively, via the heat dissipation fins 4, and the heights of the pressure members 5 at the contact points with the heat dissipation fins 4 are different from each other. This ensures the ability to follow the heat dissipation fins 4 and the semiconductor devices 8.

[0034] (3) One pressure member 5 corresponds to a plurality of heat dissipation fins 4. This contributes to improving ease of installation and reducing costs.

[0035] (4) The refrigerant flow path member has a frame 3 that fixes the heat dissipation fins 4 within the refrigerant flow path, and the pressure member 5 has protrusions 13 between adjacent heat dissipation fins 4, and the protrusions 13 contact the frame 3. This contributes to improving the positioning of the pressure member 5.

[0036] (5) The semiconductor device 8 and the heat dissipation fins are at the same potential, the coolant is non-conductive, and the coolant flow path member has an insulating member 10 at the portion that contacts the pressure member 5. This ensures insulation.

[0037] (6) The insulating member 10 has the first protrusion 10a that protrudes toward the heat dissipation fin 4. This configuration improves heat dissipation and ensures reliability.

[0038] (7) The insulating member 10 has the second protruding portion 10b that is inclined with respect to the flow direction 6 of the refrigerant flow path. This configuration can improve heat dissipation.

[0039] The present invention is not limited to the above-described embodiments, and various modifications and combinations of other configurations are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited to those having all of the configurations described in the above-described embodiments, and includes those in which some of the configurations are omitted.

[0040] 2 Cover 2a Fastening portion 3 Frame 3a Through hole 4 Radiation fin 5 Pressurizing member 5a First pressing member 5b Second pressing member 5c Third pressing member 6 Coolant flow direction 7 Heat conduction member 8 Semiconductor device 9 Sealing member 10 Insulating member 10a First protruding portion 10b Second protruding portion 11 Inclined portion 11a First inclined portion 11b Second inclined portion 12 Base portion 13 Convex portion 14 Coolant flow path

Claims

1. A power conversion device comprising: a semiconductor device having a built-in semiconductor element; a heat dissipation fin thermally connected to the semiconductor device via a heat conduction member; a refrigerant flow path member having a refrigerant flow path formed therein through which a refrigerant flows and liquid-tightly holding the heat dissipation fin so as to allow relative displacement; and a pressure member disposed between the heat dissipation fin and an inner peripheral surface of the refrigerant flow path member facing the heat dissipation fin, and biasing the heat dissipation fin toward the semiconductor device, wherein the pressure member has a base portion abutting against the tip of the heat dissipation fin, and an inclined portion formed at an angle from the base portion in the direction of the flow of the refrigerant and extending to the inner peripheral surface.

2. A power conversion device according to claim 1, wherein the pressure members face the semiconductor devices via the heat dissipation fins, and the heights of the pressure members at the contact points with the heat dissipation fins are different from each other.

3. A power conversion device according to claim 1, wherein one of the pressure members corresponds to a plurality of the heat dissipation fins.

4. A power conversion device according to claim 1, wherein the refrigerant flow path member has a frame that fixes the heat dissipation fins within the refrigerant flow path, and the pressure member has a protrusion located between adjacent heat dissipation fins, and the protrusion comes into contact with the frame.

5. A power conversion device according to claim 1, wherein the semiconductor device and the heat dissipation fins are at the same potential, the coolant is non-conductive, and the coolant flow path member has an insulating member at a portion that abuts against the pressure member.

6. A power converter according to claim 5, wherein the insulating member has a first protrusion that protrudes toward the heat dissipation fin.

7. A power converter according to claim 6, wherein the insulating member has a second protruding portion that is inclined with respect to the flow direction of the refrigerant.

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