Power module, power conversion device, and electric vehicle

Abstract

This disclosure provides a power module, a power conversion device, and an electric vehicle, belonging to the field of new energy vehicle technology. The power module includes a substrate, at least one power chip, a heat sink, and a solder layer. The at least one power chip is located on the surface of the substrate. The surface of the substrate facing away from the power chip and / or the surface of the heat sink have a crack-resistant structure. The surface of the substrate facing away from the power chip and the surface of the heat sink are interconnected through the solder layer, and the crack-resistant structure is located within the solder layer. The outer edge of the crack-resistant structure's orthographic projection on the surface of the substrate facing away from the power chip surrounds all the power chips. The spacing between the facing surfaces of the substrate and the heat sink is not equal in the region with the crack-resistant structure compared to the region without it. Adopting this disclosure can improve the long-term reliability and stability of post-soldering interconnects.

Description

Technical Field

[0001] This disclosure relates to the field of new energy vehicle technology, and in particular to a power module, a power conversion device, and an electric vehicle. Background Technology

[0002] A power conversion device is used to convert AC power between different AC sources, AC power to DC power, or DC power to DC power. For example, the motor control unit (MCU) in an electric vehicle is a power conversion device. As one of the core components of an electric vehicle, the MCU receives instructions from the vehicle control unit (VCU), obtains electrical energy from the battery pack, and converts the DC power supplied by the battery pack into AC power required by the motor via its internal power module, thus driving the electric vehicle. During deceleration, the MCU can also convert AC power back to DC power through its internal power module to charge the battery pack.

[0003] Because the power module inside the motor control unit generates a large amount of heat during power conversion, the power module is generally interconnected with a heat sink to transfer the heat to the heat sink, which then dissipates the heat to the outside. Among the interconnection methods between the power module and the heat sink, welding interconnection is less expensive than sintering interconnection and has better heat transfer performance than interconnection through thermal interface material (TIM), making it a research hotspot in this field.

[0004] However, in the interconnection method between power modules and heat sinks by welding, the power module, which is manufactured using semiconductor technology, has a substrate made of insulating ceramic, while the heat sink's heat dissipation base plate is made of metal. This results in a large difference in the coefficient of thermal expansion (CTE) between the power module's substrate and the heat sink's heat dissipation base plate. Therefore, under temperature changes, the deformation of the substrate and the heat sink's heat dissipation base plate are inconsistent, making it easy for large cracks to form at the weld joint between the substrate and the heat sink's heat dissipation base plate. Summary of the Invention

[0005] This disclosure provides a power module, a power conversion device, and an electric vehicle that can slow down the propagation of cracks at the weld joint between the power module and the heat sink, thereby reducing the likelihood of large cracks forming at the weld joint and improving the long-term reliability and stability of the interconnection between the power module and the heat sink.

[0006] In a first aspect, this disclosure provides a power module, the power module including a substrate, at least one power chip, a heat dissipation base plate and a solder layer;

[0007] The at least one power chip is located on the surface of the substrate, the surface of the substrate facing away from the power chip and / or the surface of the heat dissipation base plate have a crack-resistant structure, the surface of the substrate facing away from the power chip and the surface of the heat dissipation base plate are interconnected through the solder layer, and the crack-resistant structure is located in the solder layer;

[0008] The outer edge of the anti-crack structure, projected onto the surface of the substrate opposite to the power chip, surrounds all the power chips on the substrate surface. The distance between the surfaces of the substrate and the heat sink facing each other is not equal in the region with the anti-crack structure and in the region without the anti-crack structure.

[0009] In the solution disclosed herein, the substrate has a crack-resistant structure on the surface facing the heat dissipation base plate and / or the heat dissipation base plate has a crack-resistant structure on the surface facing the substrate. The crack-resistant structure makes the spacing between the surfaces of the substrate and the heat dissipation base plate not uniform everywhere, resulting in an uneven contact interface between the substrate and the solder layer, and / or an uneven contact interface between the heat dissipation base plate and the solder layer. Since cracks tend to propagate more easily on smooth interfaces and less easily on uneven interfaces, the crack-resistant structure on the surface facing the heat dissipation base plate and / or the surface facing the heat dissipation base plate can delay the continued propagation of cracks in the event of cracking in the solder layer.

[0010] Furthermore, the outer edge of the anti-crack structure projected onto the substrate surface surrounds all power chips on the substrate surface. Since the anti-crack structure is relatively close to the edge of the solder layer, even if the solder layer cracks at the edge, the crack will only be small or short between the crack point and the anti-crack structure. Therefore, by adopting this disclosure, even if the substrate and the heat sink base plate crack at the solder layer, it is not easy to produce large cracks.

[0011] In addition, because the outer edge of the anti-crack structure's orthogonal projection on the substrate surface surrounds all the power chips on the substrate surface, the solder layer is less likely to crack at the location of the corresponding power chip, thus ensuring good heat transfer between the substrate and the heat dissipation base plate at the location of the corresponding power chip and accelerating heat dissipation for the power chip.

[0012] In one possible implementation, the area of ​​the region enclosed by the outer edge of the anti-crack structure on the surface of the substrate opposite to the power chip is greater than or equal to the area occupied by all the power chips on the surface of the substrate.

[0013] In the scheme shown in this disclosure, the above area relationship enables the outer edge of the orthographic projection of the anti-crack structure on the substrate surface to surround all power chips on the substrate surface.

[0014] In one possible implementation, the crack-blocking structure is a protrusion structure or a groove structure.

[0015] In the solutions disclosed herein, the raised or recessed structures enable the spacing between the facing surfaces of the substrate and the heat sink to be unequal in areas with the anti-crack structure compared to areas without it. For example, if the anti-crack structure is a raised structure, the spacing between the facing surfaces of the substrate and the heat sink in areas with the raised structure is smaller than the spacing in areas without it. Similarly, if the anti-crack structure is a recessed structure, the spacing between the facing surfaces of the substrate and the heat sink in areas with the recessed structure is smaller than the spacing in areas without it.

[0016] In one possible implementation, the crack-blocking structure is a boss, and the area of ​​the boss's surface is greater than or equal to the area occupied by all the power chips on the substrate surface; or, the crack-blocking structure is a groove, and the area of ​​the groove's bottom is greater than or equal to the area occupied by all the power chips on the substrate surface.

[0017] In the scheme shown in this disclosure, the crack-blocking structure is a boss with a relatively large area or a groove with a relatively large bottom area, which can realize the outer edge of the orthogonal projection of the crack-blocking structure on the substrate surface, surrounding all power chips on the substrate surface.

[0018] In one possible implementation, the crack-blocking structure is an annular protrusion or an annular groove.

[0019] In the scheme disclosed herein, the crack-blocking structure is an annular protrusion or an annular groove, which also allows the outer edge of the orthographic projection of the crack-blocking structure on the substrate surface to surround all power chips on the substrate surface. Moreover, the annular protrusion or annular groove of the crack-blocking structure is also beneficial to enhance the crack-blocking structure's ability to hinder crack propagation.

[0020] In one possible implementation, the heat dissipation base plate has a plurality of support pillars on its surface facing the substrate, and the orthographic projection of the anti-crack structure on the surface of the heat dissipation base plate facing the substrate covers all the support pillars.

[0021] In the scheme disclosed herein, if the crack-prevention structure is disposed on the surface of the heat dissipation base plate, then the support column is arranged on the crack-prevention structure. For example, if the crack-prevention structure is a raised structure, then the support column is located on the platform of the raised structure, wherein the raised structure can be a boss with a relatively large platform area or an annular raised structure. As another example, if the crack-prevention structure is a groove structure, then the support column is located on the bottom of the groove structure, wherein the groove structure can be a groove with a relatively large bottom area or an annular groove.

[0022] If the crack-resistant structure is located on the surface of the substrate, then the top surface of the support pillar facing away from the heat sink base plate will contact the crack-resistant structure. For example, if the crack-resistant structure is a raised structure, then the top surface of the support pillar will contact the platform of the raised structure. The raised structure can be a large platform or an annular raised structure. Alternatively, if the crack-resistant structure is a groove structure, then the top surface of the support pillar will contact the bottom of the groove structure. The groove structure can be a large groove or an annular groove.

[0023] In one possible implementation, the heat sink base plate has a plurality of support pillars on its surface facing the substrate, and the crack-blocking structure surrounds all the support pillars by the inner edge of its orthographic projection onto the surface of the heat sink base plate facing the substrate. Here, "all the support pillars" refers to all the support pillars corresponding to a single power module, excluding the support pillars corresponding to other power modules connected to the heat sink.

[0024] In the scheme shown in this disclosure, the crack-blocking structure is an annular protrusion or an annular groove, and multiple support columns are positioned relative to the space inside the ring.

[0025] In one possible implementation, the area enclosed by the outer edge of the anti-crack structure on the surface of the substrate facing the heat dissipation base plate is smaller than the area of ​​the area on the surface of the substrate facing the heat dissipation base plate that is in contact with the solder layer.

[0026] In one possible implementation, the crack-resistant structure is located on the surface of the substrate facing the heat dissipation base plate, and the angle between the outer side surface of the solder layer and the surface of the substrate facing the heat dissipation base plate is greater than 0 degrees and less than or equal to 90 degrees, or...

[0027] The crack-resistant structure is located on the surface of the heat dissipation base plate facing the substrate, and the angle between the outer side surface of the welding layer and the surface of the heat dissipation base plate facing the substrate is greater than 0 degrees and less than or equal to 90 degrees.

[0028] In the scheme disclosed herein, the angle between the surface of the substrate and the side of the solder layer is greater than 0 degrees and less than or equal to 90 degrees. The intersection between the surface of the substrate and the side of the solder layer is a crack-prone location that is prone to cracking. However, the surface of the substrate has a crack-resistant structure. Under the action of the crack-resistant structure, even if a crack is generated at the crack-prone location, the crack is difficult to continue to propagate due to the obstruction of the crack-resistant structure. Thus, even if a crack is generated between the substrate and the solder layer, the crack is relatively small.

[0029] In the solution disclosed herein, the angle between the heat dissipation base plate and the side of the welding layer is greater than 0 degrees and less than or equal to 90 degrees. The intersection between the surface of the heat dissipation base plate and the side of the welding layer is a crack-prone location. However, the surface of the heat dissipation base plate has a crack-resistant structure. Under the action of the crack-resistant structure, even if a crack is generated at the crack-prone location, the crack is difficult to continue to expand due to the obstruction of the crack-resistant structure. Thus, even if a crack is generated between the heat dissipation base plate and the welding layer, the crack is relatively small.

[0030] In one possible implementation, the substrate is a copper-clad ceramic plate, including a ceramic plate, a first copper-clad layer located on a first surface of the ceramic plate, and a second copper-clad layer located on a second surface of the ceramic plate, wherein the first surface and the second surface of the ceramic plate are positioned opposite each other.

[0031] The at least one power chip is fixed on the first copper-clad layer, the surface of the second copper-clad layer and / or the heat sink has the crack-resistant structure, and the second copper-clad layer and the surface of the heat sink are interconnected through the solder layer.

[0032] In the scheme shown in this disclosure, the substrate and the heat dissipation base plate are interconnected by a solder layer, that is, the second copper clad layer and the heat dissipation base plate are interconnected by a solder layer, and the substrate surface has a crack-resistant structure, that is, the second copper clad layer has a crack-resistant structure.

[0033] In one possible implementation, the area of ​​the solder layer in contact with the second copper cladding layer is less than or equal to the area of ​​the second copper cladding layer.

[0034] In one possible implementation, the power module further includes a molding compound, in which the substrate and the at least one power chip are located, and an area of ​​the substrate's surface facing away from the power chip for interconnection with the heat sink is exposed outside the molding compound.

[0035] In the scheme disclosed herein, the power chip is first packaged using a plastic encapsulator to form a power module. Then, the substrate of the power module and the heat sink are soldered together using solder. This method of packaging before soldering is more beneficial to protecting the power chip and preventing it from being affected by the soldering process, compared to soldering before packaging.

[0036] In one possible implementation, the power module further includes heat dissipation fins fixed to the surface of the heat dissipation base plate opposite to the substrate.

[0037] In the scheme shown in this disclosure, heat dissipation fins are arranged on the surface of the heat dissipation base plate, which helps to increase the heat dissipation area of ​​the heat dissipation base plate and accelerate the heat dissipation of the power chip by the heat sink.

[0038] In one possible implementation, the power module further includes a heat dissipation channel, with the side of the heat dissipation base plate facing away from the power chip facing the heat dissipation channel, and the heat dissipation base plate in contact with the heat dissipation medium within the heat dissipation channel.

[0039] In the scheme disclosed herein, the heat dissipation medium continuously absorbs heat from the heat dissipation base plate as it flows within the heat dissipation channel, thereby achieving the effect of dissipating heat from the heat dissipation base plate.

[0040] In a second aspect, a power conversion device is provided, the power conversion device including a housing, a circuit board and any of the power modules described in the first aspect;

[0041] Both the circuit board and the power module are located in the housing, and the power chip of the power module is electrically connected to the circuit board.

[0042] Thirdly, an electric vehicle is provided, the electric vehicle including a vehicle control unit, a motor, a power battery and a motor control unit, wherein the motor control unit is the power conversion device described in the second aspect;

[0043] The vehicle control unit is used to send control commands to the motor control unit, and the motor control unit is used to control the output torque and speed of the motor based on the control commands, and to convert the DC power provided by the power battery into AC power required by the motor. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the structure of a power module provided in an exemplary embodiment of the present disclosure;

[0045] Figure 2 This is a partial structural schematic diagram of a power module provided in another exemplary embodiment of this disclosure;

[0046] Figure 3 This is a partial structural schematic diagram of a power module provided in another exemplary embodiment of this disclosure;

[0047] Figure 4 This is a partial structural schematic diagram of a power module provided in another exemplary embodiment of this disclosure;

[0048] Figure 5This is a schematic diagram of the orthographic projection of the crack-resistant structure and welding layer provided in an exemplary embodiment of the present disclosure onto the surface of the substrate facing the heat dissipation base plate.

[0049] Figure 6 This is a schematic diagram of the structure of a power module provided in another exemplary embodiment of this disclosure;

[0050] Figure 7 This is a schematic diagram of the structure of a power module provided in another exemplary embodiment of this disclosure;

[0051] Figure 8 This is a schematic diagram of the structure of a power module provided in another exemplary embodiment of this disclosure;

[0052] Figure 9 This is a schematic diagram of the structure of a power module provided in another exemplary embodiment of this disclosure;

[0053] Figure 10 This is a schematic diagram of the orthographic projection of the crack-resistant structure provided in an exemplary embodiment of the present disclosure onto the substrate-facing surface of the heat dissipation base plate;

[0054] Figure 11 This is a schematic diagram of the orthographic projection of the crack-resistant structure provided in another exemplary embodiment of this disclosure onto the substrate-facing surface of the heat dissipation base plate;

[0055] Figure 12 This is a schematic diagram of the orthographic projection of the crack-resistant structure provided in another exemplary embodiment of this disclosure onto the substrate-facing surface of the heat dissipation base plate;

[0056] Figure 13 This is a partial structural schematic diagram of a power module provided in another exemplary embodiment of this disclosure;

[0057] Figure 14 This is a partial structural schematic diagram of a power module provided in another exemplary embodiment of this disclosure.

[0058] Explanation of reference numerals in the attached figures

[0059] 1. Power module.

[0060] 11. Substrate; 111. Ceramic plate; 112. First copper cladding layer; 113. Second copper cladding layer.

[0061] 12. Power chip.

[0062] 13. Plastic-sealed parts.

[0063] 2. Radiator; 21. Heat sink base plate; 22. Heat sink fins; 211. Support column.

[0064] 3. Welding layer; 31. Side surface.

[0065] 4. Locations prone to cracking.

[0066] 5. Crack-resistant structure; 51. Outer edge; 52. Inner edge. Detailed Implementation

[0067] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0068] This embodiment relates to a power conversion device, which can be a motor control unit in an electric vehicle or a device in an energy storage system (such as an uninterruptible power supply or a transformer). This embodiment does not provide specific application examples for the power conversion device. For instance, the power conversion device is the motor control unit (MCU) of an electric vehicle. The motor control unit, also known as a motor controller, is mainly used to control the output torque and speed of the motor based on control commands sent by the vehicle control unit (VCU), and to convert the DC power obtained from the power battery pack into the AC power required by the motor. Therefore, the motor control unit will include a power module for implementing power conversion.

[0069] The power module can be used to convert DC to AC, AC to DC, and DC to AC conversion, as well as to convert between DC and AC. This embodiment does not limit the specific functions of the power module.

[0070] The power module generates a lot of heat during power conversion, so the motor control unit also includes a heat sink. The power module and the heat sink are interconnected to form a power module.

[0071] The power module structurally includes a substrate and components arranged on the substrate (such as power chips, capacitors, resistors and inductors). The heat sink structurally includes a heat sink base plate and heat sink fins. Therefore, the interconnection between the power module and the heat sink is the interconnection between the substrate of the power module and the heat sink base plate of the heat sink.

[0072] Currently, the traditional interconnection method between power modules and heat sinks involves using thermal interface material (TIM). For example, TIM is used to fill the gap between the power module's substrate and the heat sink's base plate to absorb the gap between them. The TIM material is typically thermally conductive silicone grease. However, the industry is generally researching interconnection methods with superior heat transfer performance, with welding and sintering being the most popular research topics. While sintering offers higher heat transfer and stability than welding, the material costs used in sintering remain high. Welding, on the other hand, offers the advantage of lower cost. Therefore, in the field of power module and heat sink interconnection, welding remains a key area for research and mass production development.

[0073] The soldering interconnection between the power module and the heat sink includes pre-soldering and post-soldering. Pre-soldering involves soldering the power module's substrate to the heat sink's base plate before encapsulation. The power module is then encapsulated, with the plastic encapsulation extending to the heat sink base plate, effectively encapsulating the solder layer between the power module and the heat sink. This prevents cracking at the contact points between the solder layer and the power module, as well as between the solder layer and the heat sink base plate. However, in the pre-soldering process, due to assembly requirements, there is a larger gap between the edge of the heat sink base plate and the outermost heat sink fins, resulting in a smaller area of ​​the heat sink fins on the base plate and slightly poorer heat dissipation performance. Furthermore, in the pre-soldering process, typically one heat sink cools one power module; the heat sink is usually smaller, with a smaller heat dissipation area, leading to slightly weaker heat dissipation performance.

[0074] Post-soldering involves first packaging the power module, and then interconnecting the packaged power module with the heatsink using a soldering process. For example, ... Figure 1 The diagram shown illustrates the interconnection of the power module and heatsink via a post-soldering process. (Refer to...) Figure 1 As shown, the molding compound 13 of the power module 1 is wrapped around the substrate 11 of the power module 1, exposing the welding surface of the substrate 11 for welding interconnection with the heat sink 2. In the post-welding interconnection process, the gap between the edge of the heat sink base plate and the outer heat sink fins is smaller, and the area of ​​the heat sink fins on the heat sink base plate is larger, resulting in better heat dissipation performance of the heat sink. In addition, in the post-welding process, one heat sink generally dissipates heat for multiple power modules, and the heat sink size is larger, with a larger heat dissipation area, resulting in stronger heat dissipation performance compared to the pre-welding process. Therefore, in the welding interconnection scheme between the power module and the heat sink, post-welding interconnection is more common.

[0075] While post-soldering processes can improve the heat dissipation performance of the heat sink, the solder layer is exposed in this process. The coefficient of thermal expansion (CTE) of the power module's substrate differs from that of the heat sink base plate. For example, the substrate is typically a copper-clad ceramic substrate, and the overall CTE of the copper-clad ceramic substrate is lower than that of the heat sink base plate. Therefore, when the temperature changes, the deformation of the substrate and the heat sink base plate are inconsistent. This makes the solder layer between the substrate and the heat sink base plate prone to cracking along the solder joint. Once cracking occurs, the crack will propagate, creating a gap between the heat sink base plate and the substrate. This gap is filled with air, which has high thermal resistance, significantly reducing heat transfer between the power module and the heat sink.

[0076] Therefore, in the process of interconnecting power modules and heat sinks through post-soldering processes, improving the long-term reliability and stability of the interconnection is currently a major research hotspot in the industry.

[0077] This embodiment provides a power module. Although the power module's substrate and the heat sink's base plate are interconnected through a post-soldering process, the surfaces of the substrate and / or the heat sink's base plate that face each other have some crack-resistant structures. These crack-resistant structures can hinder crack propagation. Therefore, even if cracks appear between the substrate and the solder layer or between the heat sink's base plate and the solder layer, the crack propagation is relatively slow or even non-existent under the action of the crack-resistant structures, thereby improving the long-term reliability and stability of the post-soldering interconnection.

[0078] The features of the power module described in this embodiment will be described in detail below.

[0079] Continue to refer to Figure 1 As shown, the power module includes a power module 1, which includes a substrate 11, at least one power chip 12, and a molding compound 13. The substrate 11 is generally a copper-clad ceramic substrate, including a ceramic plate 111, a first copper-clad layer 112 on a first surface of the ceramic plate 111, and a second copper-clad layer 113 on a second surface of the ceramic plate 111. The first and second surfaces are positioned opposite each other. All the power chips 12 included in a single power module 1 are located on the first copper-clad layer 112; the figure shows an example with two power chips 12. The first copper-clad layer 112 is used to implement electrical connections, such as electrical connections between power chips 12 and electrical connections between power chips 12 and other components. The second copper-clad layer 113 is used for soldering to a heat sink, and the ceramic plate 111 is used to provide electrical isolation between the first and second copper-clad layers 112 and 113.

[0080] It should be noted that the first copper clad layer 112 and the second copper clad layer 113 are made of the same material, which is metallic copper. This can avoid the difference in CTE caused by different materials. However, the thickness of the first copper clad layer 112 and the second copper clad layer 113 can be equal or unequal, and their areas can also be equal or unequal.

[0081] Continue to refer to Figure 1 As shown, the molding compound 13 encapsulates the substrate 11, but the area of ​​the second copper-clad layer 113 used for soldering with the heat sink 2 needs to be exposed so that the power module 1 can be soldered to the heat sink 2 after the encapsulation is completed.

[0082] Of course, the power module 1 will also include some components (not shown in the figure), such as capacitors, resistors and inductors, which are electrically connected to the first copper layer 112. The power module 1 also has pins (not shown in the figure) extending out of the plastic package 13 to realize external electrical connection.

[0083] Continue to refer to Figure 1 As shown, the power module also includes a heat sink 2 for dissipating heat from the power module 1. The heat sink 2 includes a heat sink base plate 21 and heat sink fins 22. The heat sink fins 22 are fixed to the surface of the heat sink base plate 21. The surface of the heat sink base plate 21 facing away from the heat sink fins 22 is used to weld to the power module 1.

[0084] Therefore, refer to Figure 1 As shown, the power module also includes a solder layer 3. The substrate 11 of the power module 1 and the heat sink 2's heat dissipation base plate 21 are interconnected through the solder layer 3. That is, the surface of the substrate 11 facing the heat dissipation base plate 21 is soldered to the solder layer 3, and the surface of the heat dissipation base plate 21 facing the substrate 11 is soldered to the solder layer 3. For example, see Reference Figure 1 As shown, the area of ​​the second copper clad layer 113 exposed from the molding compound 13 is welded to the solder layer 3, and the surface of the heat sink base plate 21 facing away from the heat sink fins 22 is welded to the solder layer 3.

[0085] Continue to refer to Figure 1 As shown, the welding layer 3 has a certain thickness, so the welding layer 3 has a side 31 (that is, the outer surface of the side). The side 31 of the welding layer 3 intersects with the surface of the substrate 11 facing the heat dissipation base plate 21, and also intersects with the surface of the heat dissipation base plate 21 facing the substrate 11.

[0086] The location where the solder layer 3 is prone to cracking (denoted as the crack-prone location) is generally the intersection between the side surface 31 of the solder layer 3 and the surface of the substrate 11 facing the heat sink 21, that is, the intersection between the side surface 31 of the solder layer 3 and the second copper cladding layer 113. Similarly, the location where the solder layer 3 is prone to cracking between the solder layer 3 and the heat sink 21 is also the intersection between the solder layer 3 and the surface of the heat sink 21 facing the substrate 11. The intersection of the side surface 31 of the solder layer 3 and the surface is called the intersection line, and any point along the intersection line is a crack-prone location.

[0087] For example, such as Figure 2 The diagram shown is a partial schematic of the interconnection between the substrate 11 and the heat dissipation base plate 21 via the solder layer 3. (Refer to...) Figure 2 As shown, the side surface 31 of the solder layer 3 is perpendicular to the surface of the substrate 11 facing the heat dissipation base plate 21 (i.e., the surface of the second copper cladding layer 113) and also perpendicular to the surface of the heat dissipation base plate 21 facing the substrate 11. Therefore, the intersection of the side surface 31 of the solder layer 3 and the surface of the substrate 11 (i.e., the intersection line) and the intersection of the side surface 31 of the solder layer 3 and the surface of the heat dissipation base plate 21 (i.e., the intersection line) are all crack-prone locations 4 (black dots in the attached figure).

[0088] For example, such as Figure 3 The diagram shown is a partial schematic of the interconnection between the substrate 11 and the heat dissipation base plate 21 via the solder layer 3. (Refer to...) Figure 3 As shown, the angle α between the side surface 31 of the solder layer 3 and the surface of the substrate 11 facing the heat dissipation base plate 21 (i.e., the surface of the second copper clad layer 113) is an acute angle less than 90 degrees, and the angle β between the side surface 31 of the solder layer 3 and the surface of the heat dissipation base plate 21 facing the substrate 11 is an obtuse angle greater than 90 degrees. Because the intersection of the side surface 31 of the solder layer 3 and the second copper clad layer 113 is relatively sharp, while the intersection of the side surface 31 of the solder layer 3 and the heat dissipation base plate 21 is relatively blunt, the sharp point is more prone to cracking than the blunt point. Therefore, the intersection of the side surface 31 of the solder layer 3 and the second copper clad layer 113 is the crack-prone position 4 (any position along the intersection line is a crack-prone position).

[0089] For example, such as Figure 4 The diagram shown is a partial schematic of the interconnection between the substrate 11 and the heat dissipation base plate 21 via the solder layer 3. (Refer to...) Figure 4 As shown, the angle α between the side surface 31 of the solder layer 3 and the surface of the substrate 11 facing the heat dissipation base plate 21 (i.e., the surface of the second copper clad layer 113) is an obtuse angle greater than 90 degrees, and the angle β between the side surface 31 of the solder layer 3 and the heat dissipation base plate 21 is an acute angle less than 90 degrees. Based on the above, the intersection of the side surface 31 of the solder layer 3 and the surface of the heat dissipation base plate 21 facing the substrate 11 is the crack-prone location 4 (where any position along the intersection line is a crack-prone location).

[0090] Regardless of whether the crack-prone location is at the intersection of the side 31 of the solder layer 3 and the substrate 11, or at the intersection of the side 31 of the solder layer 3 and the heat sink base plate 21, once a crack is generated at the crack-prone location 4, the crack will easily propagate inward along the surface. If no intervention is provided, a long gap will be generated between the solder layer 3 and the surface where the crack is located. The gap will be filled with air, and the air has a relatively high thermal resistance, which will reduce the heat transfer between the power module and the heat sink.

[0091] Therefore, in this embodiment, a crack-blocking structure 5 is provided on the surface of the substrate 11 facing away from the power chip 12 and / or on the surface of the heat dissipation base plate 21 facing away from the heat dissipation fins 22. For example, the second copper clad layer 113 of the substrate 11 has a crack-blocking structure 5 on the surface of the heat dissipation base plate 21 facing the substrate 11. For example, the second copper clad layer 113 of the substrate 11 has a crack-blocking structure 5, and the surface of the heat dissipation base plate 21 facing the substrate 11 also has a crack-blocking structure 5.

[0092] In this embodiment, it is not specifically limited whether the crack-blocking structure 5 is provided on the second copper cladding layer 113 of the substrate 11, on the surface of the heat dissipation base plate 21, or on both surfaces. Unless otherwise specified, the following text uses the example of providing the crack-blocking structure 5 on the surface of the substrate 11.

[0093] The crack-blocking structure 5 is used to prevent crack propagation. The principle behind the crack-blocking structure 5 preventing crack propagation is that the distance between the facing surfaces of the substrate 11 and the heat dissipation base plate 21 is not equal in the area with the crack-blocking structure 5 and in the area without the crack-blocking structure 5, making the contact interface between the solder layer 3 and the substrate 11 uneven, and / or making the contact interface between the solder layer 3 and the heat dissipation base plate 21 uneven. Furthermore, since the smoother the contact interface, the easier it is for cracks to propagate, and the more uneven the contact interface, the less likely it is for cracks to propagate, the crack-blocking structure 5 can prevent crack propagation.

[0094] For example, if the crack-blocking structure 5 is on the surface of the substrate 11, and cracks occur at the intersection of the side 31 of the solder layer 3 and the surface of the substrate 11, the cracks generated by the cracks will propagate along the contact interface between the substrate 11 and the solder layer 3. Since there is a crack-blocking structure on this contact interface, the contact interface is uneven. The more uneven the contact interface, the less likely the cracks will propagate. Therefore, the crack-blocking structure 5 on the surface of the substrate 11 can prevent the cracks on the contact interface between the substrate 11 and the solder layer 3 from propagating inward.

[0095] Similarly, the crack-resistant structure 5 on the surface of the heat dissipation base plate 21 can prevent the cracks on the contact interface between the heat dissipation base plate 21 and the welding layer 3 from propagating inward.

[0096] In one example, the heat generated by power module 1 is mainly the heat generated by power chip 12 during operation. Therefore, heat sink 2 is primarily for cooling power chip 12. (Refer to...) Figure 5 As shown, the outer edge 51 of the anti-crack structure 5, projected onto the surface of the substrate 11 opposite to the power chip 12, surrounds all the power chips 12 on the surface of the substrate 11. In this way, the welding interface between the welding layer 3 and the substrate 11, and the welding interface between the welding layer 3 and the heat dissipation base plate 21, are less likely to crack at the positions corresponding to each power chip 12, thereby enabling the heat generated by the power chip 12 to be quickly transferred to the heat sink 2 for heat dissipation.

[0097] In one example, the outer edge 51 of the orthogonal projection of the anti-crack structure 5 onto the surface of the substrate 11 opposite to the power chip 12 surrounds all the power chips 12 on the surface of the substrate 11, for example, referring to... Figure 5 As shown, the area enclosed by the outer edge 51 of the anti-crack structure 5 on the surface of the substrate 11 opposite to the power chip 12 is larger than the area occupied by all the power chips 12 on the surface of the substrate 11.

[0098] Although the area enclosed by the outer edge 51 of the anti-crack structure 5 on the surface of the substrate 11 opposite to the power chip 12 is larger than the area occupied by all the power chips 12 on the surface of the substrate 11, the area enclosed by the outer edge 51 cannot be infinitely large. Therefore, continue to refer to... Figure 5 As shown, the area enclosed by the outer edge 51 of the anti-crack structure 5 on the surface of the substrate 11 facing the heat dissipation base plate 21 is smaller than the area of ​​the area on the surface of the substrate 11 facing the heat dissipation base plate 21 that is in contact with the welding layer 3.

[0099] Among them, the area on the surface of the substrate 11 facing the heat dissipation base plate 21 and in contact with the solder layer 3 is referenced. Figure 1 As shown, specifically the second copper-clad layer 113. Therefore, the area enclosed by the outer edge 51 of the crack-resistant structure 5 projected onto the surface of the substrate 11 facing the heat dissipation base plate 21 is smaller than the area of ​​the second copper-clad layer 113. Since the function of the second copper-clad layer 113 is to be soldered to the solder layer 3, the area of ​​the solder layer 3 used for soldering to the substrate 11 is less than or equal to the area of ​​the second copper-clad layer 113. In the attached diagram, this is illustrated by showing that the area of ​​the surface of the solder layer 3 facing the substrate 11 is equal to the area of ​​the second copper-clad layer 113.

[0100] As described above, the anti-crack structure 5 makes the spacing between the surfaces of the substrate 11 and the heat dissipation base plate 21 facing each other unequal. Specifically, the anti-crack structure 5 can be a protrusion structure or a groove structure.

[0101] In one example, such as Figure 6 As shown, the crack-blocking structure 5 can specifically be a boss, which is relatively large. For example, the area of ​​the boss's surface is larger than the area occupied by all the power chips 12 on the surface of the substrate 11. This satisfies the requirement that the area enclosed by the outer edge 51 of the crack-blocking structure 5 on the surface of the substrate 11 opposite to the power chips 12 is larger than the area occupied by all the power chips 12.

[0102] In another example, such as Figure 7 As shown, the crack-blocking structure 6 can specifically be a groove. The size of the groove is relatively large. For example, the bottom area of ​​the groove is larger than the area occupied by all the power chips 12 on the surface of the substrate 11, so that the area enclosed by the outer edge 51 of the crack-blocking structure 5 on the surface of the substrate 11 opposite to the power chip 12 is larger than the area occupied by all the power chips 12 on the surface of the substrate 11.

[0103] In another example, such as Figure 8 As shown, the crack-blocking structure 5 can be a ring-shaped protrusion or a ring-shaped pillar. The area of ​​the region enclosed by the outer ring side of the ring-shaped protrusion is greater than the area occupied by all the power chips 12 on the surface of the substrate 11. This satisfies the requirement that the area of ​​the region enclosed by the outer edge 51 of the crack-blocking structure 5 on the surface of the substrate 11 opposite to the power chip 12 is greater than the area occupied by all the power chips 12 on the surface of the substrate 11.

[0104] In another example, such as Figure 9 As shown, the crack-blocking structure 5 can specifically be an annular groove. The area of ​​the region enclosed by the outer annular groove wall is greater than the area occupied by all the power chips 12 on the surface of the substrate 11, thereby satisfying that the area of ​​the region enclosed by the outer edge 51 of the crack-blocking structure 5 on the surface of the substrate 11 opposite to the power chip 12 is greater than the area occupied by all the power chips 12 on the surface of the substrate 11.

[0105] refer to Figures 6 to 9 As shown, the crack-blocking structure 5 with annular protrusions and annular grooves, compared to Figure 6 The boss shown, and Figure 7 The groove shown has a better crack-prevention effect because the annular protrusion and the annular groove have two vertical planes that are perpendicular to the crack propagation direction, both of which can hinder crack propagation.

[0106] In one example, for the crack-blocking structure 5 disposed on the second copper clad layer 113, specifically in the form of a groove structure, the depth of the groove can be less than the thickness of the second copper clad layer 113, or the depth of the groove can be equal to the thickness of the second copper clad layer 113. In this case, the depth of the groove being less than the thickness of the second copper clad layer 113 is beneficial to increasing the bonding between the solder and the bottom of the groove.

[0107] In one example, reference Figure 9 As shown, the surface of the heat sink 21 facing the substrate 11 has multiple support pillars 211, which are used to ensure the thickness of the solder layer 3. This is because if there were no support pillars 211 on the surface of the heat sink 21 facing the substrate 11, the molten solder would collapse during soldering of the heat sink 21 and the substrate 11, causing the substrate 11 to tilt relative to the heat sink 21, which would exacerbate cracking between the heat sink 21 and the substrate 11. Therefore, multiple support pillars 211 are generally provided on the surface of the heat sink 21 facing away from the heat dissipation fins 22, for example, as shown in the reference... Figure 10 As shown, the heat dissipation base plate 21 is quadrilateral. Therefore, the number of support columns 211 can be four (of course, it can also be two, three or other numbers; for ease of explanation, four are used as an example), which are located at the four apex positions of the heat dissipation base plate 21.

[0108] Regarding the positional relationship between the multiple support pillars 211 and the crack-blocking structure 5, in one example, all the support pillars 211 can be positioned relative to the crack-blocking structure 5 in the thickness direction. That is, the orthogonal projection of the crack-blocking structure 5 on the surface of the heat dissipation base plate 21 facing the substrate 11 covers all the support pillars 211.

[0109] For example, the crack-resistant structure 5 is as follows: Figure 6 and Figure 7 In the solutions shown, which feature relatively large bosses or recesses, refer to... Figure 10 As shown, the orthographic projection of a relatively large boss or groove on the surface of the heat dissipation base plate 21 facing the substrate 11 covers all the support pillars 211.

[0110] For example, in a design where the crack-blocking structure 5 is an annular protrusion or an annular groove, refer to... Figure 11 As shown, the orthographic projection of the annular protrusion or annular groove on the surface of the heat sink base plate 21 facing the substrate 11 includes the outer edge 51 and the inner edge 52, and all the support pillars 211 are located in the annular region between the outer edge 51 and the inner edge 52.

[0111] In another example, where the crack-blocking structure 5 is an annular protrusion or an annular groove, all the support pillars 211 can also be offset from the crack-blocking structure 5 in the thickness direction. For example, the inner edge 52 of the crack-blocking structure 5, projected onto the surface of the heat sink 21 facing the substrate 11, surrounds all the support pillars 211. (See reference) Figure 12 As shown, the orthographic projection of the annular protrusion or annular groove on the surface of the heat dissipation base plate 21 facing the substrate 11 includes the outer edge 51 and the inner edge 52, and all the support columns 211 are located in the area enclosed by the inner edge 52.

[0112] As mentioned above, the crack-prevention structure 5 serves to prevent the crack from continuing to propagate after it has formed. Therefore, when the power module 1 and the heat sink 2 are interconnected through the welding layer 3, the crack-prone position 4 and the crack-prevention structure 5 are made coplanar. In this way, once the crack-prone position 4 cracks, the crack-prevention structure 5 on the crack propagation plane can achieve a good crack-prevention effect.

[0113] For example, such as Figure 13 The image shown is a partial schematic diagram of the power module. Figure 13 The example of the crack-resistant structure 5 is a ring-shaped protrusion, see reference. Figure 13 As shown, the crack-prevention structure 5 is disposed on the surface of the substrate 11 facing away from the power chip 12, that is, the crack-prevention structure 5 is disposed on the second copper-clad layer 113 of the substrate 11. When the second copper-clad layer 113 and the heat sink 21 are interconnected by soldering, the angle α between the outer side surface (i.e., side surface 31) of the solder layer 3 and the second copper-clad layer 113 is greater than 0 degrees and less than or equal to 90 degrees, making the intersection between the side surface 31 of the solder layer 3 and the second copper-clad layer 113 a crack-prone location. Thus, even if a crack develops at this crack-prone location, the crack's propagation along the contact interface between the second copper-clad layer 113 and the solder layer 3 is hindered by the presence of the annular protrusion, preventing further inward propagation and ensuring good heat transfer between the power module 1 and the heat sink 2.

[0114] For example, refer to Figure 14 The image shown is a partial schematic diagram of the power module. Figure 14 The example of the crack-resistant structure 5 is a ring-shaped protrusion, see reference. Figure 14As shown, the crack-prevention structure 5 is disposed on the surface of the heat sink base plate 21 opposite to the heat sink fins 22. When the second copper-clad layer 113 and the heat sink base plate 21 are interconnected by soldering, the angle β between the outer side surface (i.e., side surface 31) of the solder layer 3 and the heat sink base plate 21 is greater than 0 degrees and less than or equal to 90 degrees. This makes the intersection between the side surface 31 of the solder layer 3 and the surface of the heat sink base plate 21 a crack-prone location. Thus, even if a crack develops at this crack-prone location, the crack's propagation along the contact interface between the heat sink base plate 21 and the solder layer 3 is hindered by the presence of the annular protrusion, preventing further inward propagation and ensuring good heat transfer between the power module 1 and the heat sink 2.

[0115] In the design where both the second copper clad layer 113 and the heat dissipation base plate 21 have crack-resistant structures 5, the crack-prone locations can be formed anywhere; for example, they can be formed on surfaces such as... Figure 13 The intersection of the side 31 of the solder layer 3 shown and the second copper cladding layer 113 can also be formed at, for example... Figure 14 The intersection of the side 31 of the welded layer 3 and the heat dissipation base plate 21.

[0116] It should be noted that after solid solder is placed between power module 1 and heat sink 2, the solid solder melts into a molten state during the soldering process. If heat sink 2 is placed below and power module 1 is placed above, then the following can be formed: Figure 13 As shown, the cross-sectional shape of the cured solder layer 3 is a trapezoid, and the crack-prone area is formed at the intersection of the side of the solder layer 3 and the second copper cladding layer 113. If the heat sink 2 is placed on top and the power module 1 on the bottom, then a structure like this can be formed. Figure 14 As shown, the cross-section of the cured weld layer 3 is inverted trapezoidal, and the crack-prone area is formed at the intersection of the side 31 of the weld layer 3 and the heat dissipation base plate 21.

[0117] In one example, to improve the heat dissipation effect of the heat sink 2, the power module also includes a heat dissipation channel. The side of the heat sink 21 facing away from the power chip faces the heat dissipation channel, where a heat dissipation medium (such as water) flows. The heat sink 21 is in contact with the heat dissipation medium in the heat dissipation channel. In this way, as the heat dissipation medium flows in the heat dissipation channel, it continuously absorbs heat from the heat sink 21, achieving the effect of dissipating heat from the heat sink 21.

[0118] It should be noted that, as described above, a single heat sink 2 can dissipate heat for multiple power modules 1. In this case, the surface of the heat sink base plate 21 facing away from the heat sink fins 22 has multiple anti-crack structures as described above, and / or, the surface of the substrate 11 facing away from the power chip 12 has multiple anti-crack structures as described above.

[0119] It should be noted that, unless otherwise specified, "all power chips" as mentioned above refers to the power chips included on the substrate of a single power module, and "all support pillars" as specified above refers to the support pillars used to support a single power module.

[0120] In this embodiment, the substrate has a crack-resistant structure on the surface facing the heat dissipation base plate and / or the heat dissipation base plate has a crack-resistant structure on the surface facing the substrate. The crack-resistant structure makes the spacing between the surfaces of the substrate and the heat dissipation base plate not equal everywhere, so the contact interface between the substrate and the solder layer is uneven, and / or the contact interface between the heat dissipation base plate and the solder layer is uneven. Since cracks tend to propagate on smooth interfaces and are less likely to propagate on uneven interfaces, the crack-resistant structure on the surface of the substrate facing the heat dissipation base plate and / or the surface of the heat dissipation base plate facing the substrate can delay crack propagation.

[0121] Furthermore, the outer edge of the anti-crack structure projected onto the substrate surface surrounds all power chips on the substrate surface. Since the anti-crack structure is relatively close to the edge of the solder layer, even if the solder layer cracks at the edge, the crack will only be small or short between the crack point and the anti-crack structure. Therefore, with this embodiment, it is not easy for large cracks to be generated at the solder layer between the substrate and the heat sink.

[0122] The smaller or shorter the cracks at the contact interface between the substrate and the solder layer, and at the contact interface between the heat sink and the solder layer, the lower the thermal resistance between the substrate and the heat sink, and the better the heat transfer between them. Therefore, in the post-soldering process where the power module is first packaged and then soldered to the heat sink, adopting this embodiment can improve the long-term reliability and stability of the post-soldering interconnect.

[0123] This embodiment also provides a power conversion device, which can be any device capable of power conversion. It can be applied in energy storage systems or in new energy vehicles, such as electric vehicles. In this case, the power conversion device can be the motor control unit of the electric vehicle. Structurally, the power conversion device can include a housing, a circuit board, and the power module described above. The circuit board and the power module are both located in the housing, and the power module of the power module is fixed and electrically connected to the circuit board. For example, the power module has pins extending out of the plastic package, and these pins are electrically connected to the circuit board to realize the electrical connection between the power chip 12 inside the power module and the circuit board.

[0124] In one example, the housing has a communication interface and a water channel interface on its shell wall. The communication interface is used to establish a communication connection with the vehicle control unit, and the water channel interface is used to connect with external water supply and return pipes.

[0125] It should be noted that, in the power module described in this embodiment, the soldered interconnection between the power module and the heat sink is a post-soldering interconnection. Therefore, the interconnection between the power module and the heat sink can be performed at the power module manufacturing plant or at the manufacturing plant of the power conversion equipment, such as the motor control unit. For example, if the power module and the heat sink are sold as a single unit, then the interconnection between the power module and the heat sink is performed at the power module manufacturing plant. Alternatively, if the power module and the heat sink are sold separately, then the interconnection between the power module and the heat sink is performed at the manufacturing plant of the power conversion equipment, such as the motor control unit.

[0126] This embodiment also provides an electric vehicle, which includes a vehicle control unit, a motor, a power battery, and the aforementioned motor control unit. The motor control unit is the aforementioned power conversion device. The vehicle control unit sends control commands to the motor control unit, which, based on the control commands, controls the output torque and speed of the motor, and converts the DC power supplied by the power battery into AC power required by the motor. Of course, during deceleration of the electric vehicle, the power module within the motor control unit can also convert the AC power generated by the generator into DC power to charge the power battery pack.

[0127] The above description is merely an optional embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A power module, characterized in that, The power module includes a substrate (11), at least one power chip (12), a heat dissipation base plate (21), and a solder layer (3); The at least one power chip (12) is located on the surface of the substrate (11), the surface of the substrate (11) facing away from the power chip (12) and / or the surface of the heat dissipation base plate (21) have a crack-resistant structure (5), the surface of the substrate (11) facing away from the power chip and the surface of the heat dissipation base plate (21) are interconnected through the welding layer (3), and the crack-resistant structure (5) is located in the welding layer (3); The outer edge (51) of the anti-cracking structure (5) on the surface of the substrate (11) facing away from the power chip (12) surrounds all the power chips (12). The distance between the surfaces of the substrate (11) and the heat sink (21) facing each other is not equal in the area with the anti-cracking structure (5) and in the area without the anti-cracking structure (5).

2. The power module according to claim 1, characterized in that, The area enclosed by the outer edge (51) of the anti-crack structure (5) on the surface of the substrate (11) opposite to the power chip (12) is greater than or equal to the area occupied by all the power chips (12).

3. The power module according to claim 1 or 2, characterized in that, The crack-blocking structure (5) is a protruding structure or a groove structure.

4. The power module according to claim 3, characterized in that, The crack-blocking structure (5) is a boss, and the area of ​​the boss is greater than or equal to the area occupied by all the power chips (12). Alternatively, the crack-blocking structure (5) is a groove, and the area of ​​the groove bottom is greater than or equal to the area occupied by all the power chips (12).

5. The power module according to claim 3, characterized in that, The crack-blocking structure (5) is an annular protrusion or an annular groove.

6. The power module according to any one of claims 1 to 5, characterized in that, The heat dissipation base plate (21) has a plurality of support columns (211) on the surface facing the substrate (11), and the crack-blocking structure (5) has an orthographic projection on the surface of the heat dissipation base plate (21) facing the substrate (11) covering all the support columns (211).

7. The power module according to claim 5, characterized in that, The heat dissipation base plate (21) has a plurality of support columns (211) on the surface facing the substrate (11), and the crack-blocking structure (5) surrounds all the support columns (211) with the inner edge (52) of the orthographic projection of the heat dissipation base plate (21) on the surface facing the substrate (11).

8. The power module according to any one of claims 1 to 7, characterized in that, The area enclosed by the outer edge (51) of the anti-crack structure (5) on the surface of the substrate (11) facing the heat dissipation base plate (21) is smaller than the area of ​​the area on the surface of the substrate (11) facing the heat dissipation base plate (21) and in contact with the welding layer (3).

9. The power module according to any one of claims 1 to 8, characterized in that, The crack-resistant structure (5) is located on the surface of the substrate (11) facing the heat dissipation base plate (21), and the angle between the outer side surface of the welding layer (3) and the surface of the substrate (11) facing the heat dissipation base plate (21) is greater than 0 degrees and less than or equal to 90 degrees, or... The crack-blocking structure (5) is located on the surface of the heat dissipation base plate (21) facing the substrate (11), and the angle between the outer side surface of the welding layer (3) and the surface of the heat dissipation base plate (21) facing the substrate (11) is greater than 0 degrees and less than or equal to 90 degrees.

10. The power module according to any one of claims 1 to 9, characterized in that, The substrate (11) is a copper-clad ceramic plate, including a ceramic plate (111), a first copper-clad layer (112) located on the first surface of the ceramic plate (111), and a second copper-clad layer (113) located on the second surface of the ceramic plate (111), wherein the first surface and the second surface of the ceramic plate (111) are opposite to each other. The at least one power chip (12) is fixed on the first copper clad layer (112), the surface of the second copper clad layer (113) and / or the heat sink (21) has the crack-resistant structure (5), and the surface of the second copper clad layer (113) and the heat sink (21) are interconnected through the solder layer (3).

11. The power module according to claim 10, characterized in that, The area of ​​the solder layer (3) in contact with the second copper cladding layer (113) is less than or equal to the area of ​​the second copper cladding layer (113).

12. The power module according to any one of claims 1 to 11, characterized in that, The power module further includes a molding compound (13), in which the substrate (11) and the at least one power chip (12) are located, and the area of ​​the substrate (11) facing away from the power chip (12) for interconnection with the heat dissipation base plate (21) is exposed in the molding compound (13).

13. The power module according to any one of claims 1 to 12, characterized in that, The power module also includes heat dissipation fins (22), which are fixed to the surface of the heat dissipation base plate (21) facing away from the substrate (11).

14. The power module according to any one of claims 1 to 13, characterized in that, The power module also includes a heat dissipation channel. The side of the heat dissipation base plate (21) facing away from the power chip (12) faces the heat dissipation channel, and the heat dissipation base plate (21) is in contact with the heat dissipation medium in the heat dissipation channel.

15. A power conversion device, characterized in that, The power conversion device includes a housing, a circuit board, and a power module as described in any one of claims 1 to 14; Both the circuit board and the power module are located in the housing, and the power chip (12) of the power module is electrically connected to the circuit board.

16. An electric vehicle, characterized in that, The electric vehicle includes a vehicle control unit, a motor control unit, a motor, and a power battery, wherein the motor control unit is the power conversion device as described in claim 15; The vehicle control unit is used to send control commands to the motor control unit, and the motor control unit is used to control the output torque and speed of the motor based on the control commands, and to convert the DC power provided by the power battery into AC power required by the motor.

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