Heat dissipation mounting structure for power device

Abstract

The utility model belongs to the field of power electronics, disclose a kind of heat dissipation mounting structure of power device, including PCB, power device, elastic heat-conducting element, radiator and connecting assembly, power device includes power device body, the elastic heat-conducting element is clamped between the power device body with the PCB, the radiator with the power device body side of departure the elastic heat-conducting element insulation connection, the radiator is connected with the PCB by the connecting assembly.This heat dissipation mounting structure of power device can reduce the risk of power device body cracking and the probability of PCB bending deformation, and both sides of power device body can be heat dissipated, with the effect of improving the heat dissipation efficiency of power device body.

Description

Technical Field

[0001] This utility model relates to the field of power electronics technology, and in particular to a heat dissipation mounting structure for power devices. Background Technology

[0002] In the prior art, power devices are usually placed between a printed circuit board (PCB) and a heat sink, and locking elements such as bolts are used to connect the PCB and the heat sink to clamp and fix the power devices between the PCB and the heat sink.

[0003] However, excessive tightening force can easily occur when tightening bolts, causing power devices to squeeze the PCB. This increases the risk of cracking of the power devices and makes the PCB prone to bending and deformation under pressure, which in turn causes cracks in other components fixed on the PCB (such as chip capacitors).

[0004] Furthermore, in the prior art, power devices can only dissipate heat on the side that is in contact with the heat sink, which reduces the heat dissipation efficiency of the power devices.

[0005] Therefore, there is an urgent need to propose a heat dissipation mounting structure for power devices to solve the above-mentioned technical problems. Utility Model Content

[0006] The purpose of this utility model is to provide a heat dissipation mounting structure for power devices. This heat dissipation mounting structure can reduce the risk of cracking of the power device body and the probability of PCB bending deformation. Furthermore, both sides of the power device body can dissipate heat, thus improving the heat dissipation efficiency of the power device body.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] The heat dissipation mounting structure for power devices includes:

[0009] PCB;

[0010] Power devices, including the power device body;

[0011] A flexible thermally conductive element is sandwiched between the power device body and the PCB.

[0012] The heat sink is insulated from the side of the power device body away from the elastic thermal conductive element.

[0013] The heat sink is connected to the PCB via the connection component.

[0014] Optionally, the PCB is provided with a stress-absorbing structure, which is arranged around the orthographic projection of the power device body on the PCB.

[0015] Alternatively, in the first direction, stress-absorbing structures are provided on both sides of the orthographic projection of the power device body on the PCB. In the second direction, the size of the orthographic projection of the power device body on the PCB is smaller than the size of the stress-absorbing structure. The first and second directions are perpendicular to each other and are both parallel to the surface of the PCB.

[0016] Optionally, the stress-absorbing structure is a groove.

[0017] Optionally, the number of power devices and flexible thermal conductive elements are both multiple and correspond one-to-one.

[0018] Optionally, all elastic thermally conductive elements are in a compressed state along the direction from the PCB to the power device body.

[0019] Optionally, the heat dissipation mounting structure of the power device also includes a thermally conductive insulating sheet sandwiched between the heat sink and the power device body.

[0020] Optionally, the flexible thermal conductive element is bonded and fixed to the power device body; and / or, the flexible thermal conductive element is bonded and fixed to the PCB.

[0021] Optionally, the compression ratio of the flexible thermal conductive element is 3%-35%.

[0022] Optionally, the thermal conductivity of the elastic thermally conductive element is greater than 1.5 W / (m·K).

[0023] Optionally, the elastic thermally conductive element is a thermally conductive silicone pad or a graphene composite foam pad.

[0024] The beneficial effects of this utility model are:

[0025] An elastic thermal conductive element is sandwiched between the power device body and the PCB. When the heat sink and the PCB are connected by a connecting component, the elastic thermal conductive element can be compressed and deformed to absorb the force of the power device body and the PCB pressing against each other. On the one hand, it can protect the power device body and reduce the risk of cracking of the power device body. On the other hand, it can reduce the probability of PCB bending and deformation, and protect other components fixed on the PCB.

[0026] In addition, the power device body is cooled by heat sinks and elastic thermal conductive elements on opposite sides, achieving the effect of heat dissipation on both sides of the power device body, which helps to improve the heat dissipation efficiency of the power device body. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the heat dissipation mounting structure of the power device provided in Embodiment 1 of this utility model;

[0028] Figure 2This is a schematic diagram of the assembly structure of the PCB and power devices provided in Embodiment 1 of this utility model;

[0029] Figure 3 This is a schematic diagram of the structure of the first bolt provided in Embodiment 1 of this utility model;

[0030] Figure 4 This is a schematic diagram of the structure of the second bolt provided in Embodiment 1 of this utility model;

[0031] Figure 5 This is a schematic diagram of the structure of the heat sink provided in Embodiment 1 of this utility model;

[0032] Figure 6 This is a schematic diagram of the PCB structure provided in Embodiment 1 of this utility model;

[0033] Figure 7 This is a schematic diagram of the power device provided in Embodiment 1 of this utility model;

[0034] Figure 8 This is a schematic diagram of the heat dissipation mounting structure of the power device provided in Embodiment 1 of this utility model (when the connecting components are not locked);

[0035] Figure 9 yes Figure 8 Enlarged view of a portion of point A in the middle;

[0036] Figure 10 This is a schematic diagram of the heat dissipation mounting structure of the power device provided in Embodiment 1 of this utility model (after the connecting components are locked);

[0037] Figure 11 yes Figure 10 Enlarged view of section B in the middle.

[0038] In the picture:

[0039] D1, First Direction; D2, Second Direction;

[0040] 100, PCB; 110, Stress-absorbing structure; 111, Groove; 120, Assembly hole; 130, Insertion hole; 200, Power device; 210, Power device body; 211, Molded enclosure; 212, Heat sink; 220, Pin; 300, Flexible thermally conductive element; 400, Heat sink; 410, First threaded hole; 500, Connecting assembly; 510, First bolt; 520, Second bolt; 521, Second threaded hole; 600, Thermally conductive insulating sheet; 700, Gap. Detailed Implementation

[0041] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0042] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0043] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0044] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0045] Example 1

[0046] This embodiment provides a heat dissipation mounting structure for power devices. This heat dissipation mounting structure can reduce the risk of cracking of the power device body and the probability of PCB bending deformation. Furthermore, heat dissipation can be achieved on both sides of the power device body, thus improving the heat dissipation efficiency of the power device body.

[0047] Specifically, such as Figure 1As shown, the heat dissipation mounting structure of the power device includes a PCB100, a power device 200, an elastic thermal conductive element 300, a heat sink 400, and a connecting assembly 500. The power device 200 includes a power device body 210. The elastic thermal conductive element 300 is sandwiched between the power device body 210 and the PCB100. The heat sink 400 is insulated from the side of the power device body 210 away from the elastic thermal conductive element 300. The heat sink 400 is connected to the PCB100 through the connecting assembly 500.

[0048] An elastic thermal conductive element 300 is sandwiched between the power device body 210 and the PCB 100. When the heat sink 400 and the PCB 100 are connected by the connecting assembly 500, the elastic thermal conductive element 300 can be compressed and deformed to absorb the mutual pressing force between the power device body 210 and the PCB 100. On the one hand, it can protect the power device body 210 and reduce the risk of cracking. On the other hand, it can reduce the probability of bending and deformation of the PCB 100 and protect other components fixed on the PCB 100.

[0049] In addition, the power device body 210 is cooled by heat sink 400 and elastic heat-conducting element 300 on opposite sides, respectively, which achieves the effect of heat dissipation on both sides of the power device body 210, which is beneficial to improving the heat dissipation efficiency of the power device body 210.

[0050] Optionally, the thermal conductivity of the elastic heat-conducting element 300 is greater than 1.5 W / (m·K). For example, the thermal conductivity of the elastic heat-conducting element 300 can be 1.5 W / (m·K), 2 W / (m·K), or 2.5 W / (m·K), etc., to ensure that the power device body 210 can dissipate more heat through the elastic heat-conducting element 300, thereby ensuring the cooling efficiency of the power device body 210.

[0051] Optionally, the elastic thermally conductive element 300 can be a thermally conductive silicone pad or a graphene composite foam pad. Both thermally conductive silicone pads and graphene composite foam pads have good elasticity and thermal conductivity, and are inexpensive, which helps to reduce production costs.

[0052] Optionally, along the direction from PCB100 to heat sink 400, the size of the elastic thermal conductive element 300 (i.e. the thickness of the elastic thermal conductive element 300) is between 0.5mm and 5mm, so that the elastic thermal conductive element 300 has sufficient compression and can also achieve good thermal conductivity.

[0053] Optionally, the elastic thermal conductive element 300 is bonded and fixed to the power device body 210 to improve the reliability and stability of the connection between the elastic thermal conductive element 300 and the power device body 210, and to prevent displacement of the elastic thermal conductive element 300 relative to the power device body 210. The elastic thermal conductive element 300 is also bonded and fixed to the PCB 100 to improve the reliability and stability of the connection between the elastic thermal conductive element 300 and the PCB 100, and to prevent displacement of the elastic thermal conductive element 300 relative to the PCB 100.

[0054] In another implementation, either the power device body 210 or the PCB 100 can be bonded to the elastic thermal conductive element 300, depending on the actual application requirements.

[0055] Optionally, the heat dissipation mounting structure of the power device further includes a thermally conductive insulating sheet 600, which is sandwiched between the heat sink 400 and the power device body 210 to achieve an insulating connection between the heat sink 400 and the power device body 210. Further, the thermally conductive insulating sheet 600 can be a ceramic sheet or a polyurethane sheet, etc.

[0056] Optionally, such as Figure 1 and Figure 2 As shown, there are multiple power devices 200 and elastic thermal conductive elements 300, and they correspond one-to-one. For example, the number of power devices 200 can be two, three, four, five, six or more, so that multiple power devices 200 can be set on the same PCB100.

[0057] Furthermore, in practical applications, due to factors such as dimensional deviations, the dimensions of different power device bodies 210 vary slightly in the direction from PCB100 to the power device body 210. For ease of description, the dimension of the power device body 210 in the direction from PCB100 to the power device body 210 is referred to as the thickness of the power device body 210. When the thicknesses of different power device bodies 210 on the same PCB100 are different, the coplanarity of the surfaces of multiple power device bodies 210 facing PCB100 is low, and the coplanarity of the surfaces of multiple power device bodies 210 facing the heat sink 400 is also low, which can lead to localized overheating of the power device body 210. Specifically, after the heat sink 400 and PCB 100 are connected by the connecting component 500, a gap 700 is likely to appear between the thin power device body 210 and PCB 100. Consequently, the power device body 210 and the thermally conductive insulating sheet 600 cannot fit tightly together, and the thermally conductive insulating sheet 600 corresponding to the power device body 210 and the heat sink 400 cannot fit tightly together either. This reduces the heat dissipation efficiency of the power device body 210 and makes the power device body 210 prone to local overheating.

[0058] In the technical solution provided in this embodiment, a corresponding elastic thermal conductive element 300 is sandwiched between each power device body 210 and the PCB 100. This allows for coplanarity compensation of multiple power device bodies 210 through the compression deformation of the elastic thermal conductive element 300, thus solving the problem of localized overheating of the power device body 210. Specifically, when the heat sink 400 and PCB 100 are connected using the connecting assembly 500, the thicker power device body 210 can cooperate with the PCB 100 to compress the elastic thermal conductive element 300 between them, allowing the thinner power device body 210 to cooperate with the PCB 100 and be sandwiched between them. This enables the thinner power device body 210 to fit tightly with its corresponding thermally conductive insulating sheet 600, and the thermally conductive insulating sheet 600 to fit tightly with the heat sink 400, reducing the probability of localized overheating of the thinner power device body 210.

[0059] Furthermore, along the direction from PCB100 to the power device body 210, all elastic thermally conductive elements 300 are in a compressed state. Each compressed elastic thermally conductive element 300 applies a force towards the heat sink 400 to its corresponding power device body 210. This ensures that each power device body 210 clamps its corresponding thermally conductive insulating sheet 600 to the heat sink 400, allowing all thermally conductive insulating sheets 600 to fit tightly against the heat sink 400. This not only further reduces the risk of localized overheating in the thinner power device body 210 but also improves the heat dissipation efficiency of all power device bodies 210.

[0060] Optionally, the compression rate of the elastic thermal conductive element 300 is 3%-35%. For example, the compression rate of the elastic thermal conductive element 300 can be 3%, 10%, 15%, 20%, 30% or 35% to ensure that the elastic thermal conductive element 300 has sufficient compression deformation, which can not only fully absorb the mutual pressing force between the power device body 210 and PCB100, but also improve the feasibility of all elastic thermal conductive elements 300 being in a compressed state.

[0061] In this embodiment, the compression ratio of the elastic thermal conductive element 300 is 3%-35%, and the thickness of the elastic thermal conductive element 300 is 0.5mm-5mm, thereby improving the coplanarity of the power device body 210 with a thickness difference within 0.5mm.

[0062] Optionally, such as Figures 1 to 6As shown, the connecting assembly 500 includes a first bolt 510 and a second bolt 520. The end of the second bolt 520 facing away from the external thread is provided with a second threaded hole 521. The second threaded hole 521 is coaxial with the second bolt 520. The PCB 100 is provided with an assembly hole 120, and the heat sink 400 is provided with a first threaded hole 410. The second bolt 520 is threadedly connected to the first threaded hole 410. The first bolt 510 passes through the assembly hole 120 and is threadedly connected to the second threaded hole 521. Thus, by screwing the first bolt 510 and the second bolt 520, the PCB 100 and the heat sink 400 can be locked together, and the PCB 100 and the heat sink 400 can cooperate to clamp the thermally conductive insulating sheet 600, the power device body 210, and the elastic thermally conductive element 300.

[0063] Furthermore, the number of assembly holes 120, first threaded holes 410, and connecting components 500 are all multiple and correspond one-to-one. The multiple assembly holes 120 are evenly distributed on the PCB 100, and the multiple first threaded holes 410 are evenly distributed on the heat sink 400. This improves the stability and reliability of the connection between the PCB 100 and the heat sink 400. In this embodiment, the number of assembly holes 120 is seven. Of course, in other embodiments, the number of assembly holes 120 can also be five, six, or eight, etc.

[0064] Optionally, the PCB100 is provided with a stress-absorbing structure 110. In the first direction D1, stress-absorbing structures 110 are provided on both sides of the orthographic projection of the power device body 210 on the PCB100. In the second direction D2, the size of the orthographic projection of the power device body 210 on the PCB100 is smaller than the size of the stress-absorbing structure 110. The first direction D1 and the second direction D2 are perpendicular to each other and parallel to the surface of the PCB100. When the heat sink 400 is connected to the PCB100 using the connecting assembly 500, the stress-absorbing structure 110 can preferentially absorb the pressure exerted on the PCB100 by the elastic heat-conducting element 300, further reducing the probability of bending deformation of the PCB100.

[0065] Furthermore, the stress-absorbing structure 110 is a groove 111. That is, in the first direction D1, grooves 111 are provided on both sides of the orthographic projection of the power device body 210 on the PCB 100. In the second direction D2, the size of the orthographic projection of the power device body 210 on the PCB 100 is smaller than the size of the groove 111. Compared with other locations on the PCB 100, the PCB 100 at the groove 111 is thinner, so the structural strength of the PCB 100 at the groove 111 is lower. When the heat sink 400 is connected to the PCB 100 by the connecting component 500, the groove 111 deforms to absorb the pressure exerted on the PCB 100 by the elastic heat-conducting element 300. In addition, setting the stress-absorbing structure 110 as a groove 111 structure can also ensure that the PCB 100 has a certain structural strength and avoid problems such as PCB 100 breakage.

[0066] Furthermore, the groove 111 is a strip-shaped groove extending along the second direction D2, so that the groove 111 can absorb the pressure applied to the PCB100 by the elastic heat-conducting element 300 more evenly in the second direction D2.

[0067] Furthermore, the distance C between the inner wall of the groove 111 facing the elastic heat-conducting element 300 and the side of the power device body 210 projected onto the PCB100 facing the groove 111 is greater than or equal to 1.5 mm, so as to improve the stress absorption effect of the groove 111, further reduce the probability of PCB100 bending deformation, and provide further protection for other components on PCB100 that are close to the groove 111.

[0068] In another embodiment, the stress-absorbing structure 110 includes a plurality of through holes spaced apart along a second direction D2. The PCB 100 between two adjacent through holes has lower structural strength. When the heat sink 400 is connected to the PCB 100 using the connecting assembly 500, the PCB 100 between two adjacent through holes deforms to absorb the pressure exerted on the PCB 100 by the elastic thermal conductive element 300.

[0069] Optionally, such as Figure 7 As shown, the power device body 210 has a molding compound 211 and a heat sink 212 on opposite sides. The molding compound 211 is attached to the elastic thermally conductive element 300, and the heat sink 212 is attached to the thermally conductive insulating sheet 600. The power device 200 also includes a lead 220, one end of which is connected to the power device body 210. The middle portion of the lead 220 is bent at 90° towards the side facing the heat sink 212. Figure 6 As shown, PCB100 has a socket 130, and the other end of pin 220 is inserted into the socket 130 and soldered to PCB100.

[0070] The following is a brief description of the assembly method of the heat dissipation mounting structure for the power device provided in this embodiment:

[0071] S1. Attach the elastic thermal conductive element 300 to the plastic encapsulation 211 of the power device body 210;

[0072] S2. Insert pin 220 into socket 130, and attach the side of elastic heat-conducting element 300 away from power device body 210 to PCB 100. At this time, the plastic encapsulation 211 of power device body 210 faces down, and the heat dissipation part 212 of power device body 210 faces up.

[0073] S3. A thermally conductive insulating sheet 600 and a heat sink 400 are sequentially placed on the heat dissipation section 212 of the power device body 210; such as Figure 8 and Figure 9 As shown, at this time, the PCB100 and heat sink 400 are not locked together using the connecting component 500. Therefore, there is a gap 700 between the elastic thermally conductive element 300 corresponding to the thinner power device body 210 and the PCB100, i.e., there is a problem of low coplanarity among the multiple power device bodies 210. The PCB100 and heat sink 400, which are sandwiched with the elastic thermally conductive element 300, the power device 200 and the thermally conductive insulating sheet 600, are inverted so that the connecting component 500 passes through the assembly hole 120 and is threadedly connected to the first threaded hole 410 to lock the PCB100 and the heat sink 400. During this process, the elastic thermally conductive element 300 is compressed and deformed, such as Figure 10 and Figure 11 As shown, at this time, the connecting assembly 500 locks the PCB100 and the heat sink 400 together. The PCB100 and the heat sink 400 apply compressive force to the elastic thermal conductive element 300 on opposite sides. The elastic thermal conductive element 300 can absorb the compressive force, preventing the plastic encapsulation 211 of the power device body 210 from cracking under pressure and preventing the PCB100 from bending and deforming under pressure. At the same time, the compressed elastic thermal conductive element 300 applies a directional force to the power device body 210, eliminating the gap 700 mentioned above, so that the power device body 210 is in close contact with the thermally conductive insulating sheet 600, and the thermally conductive insulating sheet 600 is in close contact with the heat sink 400, improving the coplanarity of all power device bodies 210, thereby enabling each power device body 210 to dissipate heat efficiently.

[0074] S4, solder pin 220 and PCB100 form a conductive connection.

[0075] It should be noted that the structure of setting one power device 200 or multiple power devices 200 on PCB100 is applicable to the heat dissipation mounting structure of the power device provided in this embodiment.

[0076] Taking a power device 200 mounted on PCB100 as an example, the power device 200 is a TO-247-4L MOSFET. The pin 220 is bent at 90° in the middle. The end of the pin 220 facing away from the power device body 210 is inserted into the socket 130 of PCB100 and soldered to PCB100. A groove 111 is formed on PCB100. The groove 111 has a size of 1mm in the first direction D1 and a size of 25mm in the second direction D2. The distance between the inner wall of the groove 111 facing the elastic thermal conductive element 300 and the side of the power device body 210 projected onto PCB100 facing the groove 111 is 2mm. The elastic thermal conductive element 300 is PORON® XRD thermal conductive foam with a thickness of 4mm and a thermal conductivity of 3.5 W / (m·K). The tightening torque of the first bolt 510 is 0.6 N·m. After the first bolt 510 and the second bolt 520 are tightened, the thickness of the elastic heat-conducting element 300 after compression is 3 mm.

[0077] Taking a PCB100 with three power devices 200 as an example, Table 1 provides a set of embodiment data and a set of comparative example data. In both the embodiment and the comparative example, three power devices 200 are provided on the same PCB100. In the embodiment, a corresponding elastic heat-conducting element 300 is sandwiched between each power device body 210 and the PCB100, and the PCB100 has a groove 111. In the comparative example, each power device body 210 is directly attached to the PCB100, and the PCB100 does not have a groove 111. In both the embodiment and the comparative example, the thickness difference between the thickest power device body 210 and the thinnest power device body 210 is 0.25 mm.

[0078]

[0079] In Comparative Example 1, the maximum temperature difference of the three power device bodies 210 was more than 12°C. After 50 thermal cycles, the breakage rate of the plastic encapsulation 211 of the power device body 210 was 8%, and deformation appeared on the PCB 100, with an assembly yield of only 82%.

[0080] In Example 1, the elastic thermal conductive elements 300 corresponding to the three power devices 200 are differentially compressed (the thickness after compression is different), the contact pressure deviation of the three power device bodies 210 is <10%, the maximum temperature difference of the three power device bodies 210 is below 3℃, after 50 thermal cycles, the breakage rate of the plastic encapsulation 211 of the power device body 210 is 0, and deformation only occurs at the groove 111 position on the PCB 100, and the assembly yield reaches 98%.

[0081] Example 2

[0082] This embodiment provides a heat dissipation mounting structure for a power device. The following mainly describes the differences between this embodiment and Embodiment 1, while the similarities will not be repeated.

[0083] The stress-absorbing structure is wound around the orthogonal projection of the power device body on the PCB. When the heat sink and PCB are connected by a connecting component, the stress-absorbing structure wound around the power device body can preferentially absorb the pressure exerted on the PCB by the elastic heat-conducting element, further reducing the probability of PCB bending deformation.

[0084] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A heat dissipation mounting structure for power devices, characterized in that, include: PCB(100); A power device (200), the power device (200) including a power device body (210); An elastic thermal conductive element (300) is sandwiched between the power device body (210) and the PCB (100), and the elastic thermal conductive element (300) is compressible and deformable; Heat sink (400), the heat sink (400) is insulated from the side of the power device body (210) away from the elastic thermal conductive element (300); A connecting assembly (500) is provided, through which the heat sink (400) is connected to the PCB (100); The PCB (100) is provided with a stress absorption structure (110), and the stress absorption structure (110) is arranged around the orthogonal projection of the power device body (210) on the PCB (100); Alternatively, in the first direction (D1), the stress-absorbing structure (110) is provided on both sides opposite to the orthographic projection of the power device body (210) on the PCB (100), and in the second direction (D2), the size of the orthographic projection of the power device body (210) on the PCB (100) is smaller than the size of the stress-absorbing structure (110). The first direction (D1) and the second direction (D2) are perpendicular to each other and are both parallel to the surface of the PCB (100).

2. The heat dissipation mounting structure for the power device according to claim 1, characterized in that, The stress-absorbing structure (110) is a groove (111).

3. The heat dissipation mounting structure for the power device according to any one of claims 1-2, characterized in that, The number of power devices (200) and elastic heat-conducting elements (300) are both multiple and correspond one-to-one.

4. The heat dissipation mounting structure for the power device according to claim 3, characterized in that, Along the direction from the PCB (100) to the power device body (210), all the elastic thermal conductive elements (300) are in a compressed state.

5. The heat dissipation mounting structure for the power device according to any one of claims 1-2, characterized in that, The heat dissipation mounting structure of the power device also includes a thermally conductive insulating sheet (600), which is sandwiched between the heat sink (400) and the power device body (210).

6. The heat dissipation mounting structure for the power device according to any one of claims 1-2, characterized in that, The elastic thermal conductive element (300) is bonded and fixed to the power device body (210); and / or, the elastic thermal conductive element (300) is bonded and fixed to the PCB (100).

7. The heat dissipation mounting structure for the power device according to any one of claims 1-2, characterized in that, The compression rate of the elastic thermal conductive element (300) is 3%-35%.

8. The heat dissipation mounting structure for the power device according to any one of claims 1-2, characterized in that, The thermal conductivity of the elastic thermally conductive element (300) is greater than 1.5 W / (m·K).

9. The heat dissipation mounting structure for the power device according to any one of claims 1-2, characterized in that, The elastic thermally conductive element (300) is a thermally conductive silicone pad or a graphene composite foam pad.

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