Heat dissipation base plate of power module
By adopting a double-body needle fin structure and gradient design on the heat dissipation base plate, the problems of low heat transfer efficiency and uneven mass distribution are solved, and efficient and uniform heat dissipation effect is achieved, which is suitable for high power density and lightweight requirements.
Patent Information
- Application Number
- CN202510477136.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-16
- Publication Date
- 2025-07-18
AI Technical Summary
The existing needle fin heat dissipation base plate has poor heat transfer efficiency, large flow resistance, and uneven mass distribution, which cannot effectively respond to high power density and lightweight requirements.
Using a double-table needle wing structure, the density and taper of each heat dissipation zone in the needle wing array gradually increase along the direction of fluid flow. Combined with interlaced arrangement and gradient design, a needle wing structure with thin and thick ends in the middle is formed, enhancing turbulent heat exchange and reducing thermal resistance.
It improves heat dissipation efficiency, achieves uniform temperature heat dissipation and uniform mass distribution, and is suitable for high power density and lightweight scenarios, reducing thermal and flow resistance.
Smart Images
Figure CN120343870A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the technical field of heat dissipation structures, and more specifically, relates to a heat dissipation base plate for a power module. Background Art
[0002] With the gradual development of power modules towards lightweight, miniaturization, and integration, their power density is increasing, resulting in an increasingly high heat flux density. Thermal stresses caused by high temperatures and significant temperature gradients may lead to problems such as bond wire detachment in power modules, cracks and holes in chips, and fractures in ceramic substrates and copper leads. It may even cause chip failure, severely reducing the performance of devices and system reliability.
[0003] The heat dissipation copper base plate with an integrated Pin-Fin structure has a simple physical structure, good flow disturbance effect, and large heat transfer area, which can significantly reduce the thermal resistance. Existing pin-fin heat dissipation base plates mostly adopt columnar structures, commonly cylindrical, elliptical cylindrical, or prismatic, and are integrated with copper substrates through cold heading or welding processes. In terms of the Pin-Fin morphology structure, the existing technology mostly adopts a uniform columnar structure, with gentle streamlines, a thick boundary layer, a low convective heat transfer coefficient, a large pressure drop, and it is impossible to optimize the surface area distribution through geometric gradient. The heat dissipation area is limited by a single size and has a large mass. In terms of the Pin-Fin arrangement layout, the existing technology mostly increases the heat transfer efficiency and achieves uniform temperature heat dissipation by reducing the pin-fin spacing or the cross-sectional area of the pin fins. However, reducing the pin-fin spacing or cross-sectional area will increase the resistance between flow channels and cause uneven mass distribution of the heat dissipation base plate. Summary of the Invention
[0004] Aiming at the defects of the existing technology, the purpose of this application is to provide a heat dissipation base plate for a power module, aiming to solve the problem of poor heat transfer efficiency of existing pin-fin heat dissipation base plates.
[0005] To achieve the above objective, this application provides a heat dissipation base plate for a power module, including a base plate body and a pin-fin array. A heat dissipation area is provided on the base plate body, and the pin-fin array is fixed on the heat dissipation area; the pin-fin array includes a plurality of double-stage body pin fins. The double-stage body pin fin includes a first stage body and a second stage body. The small-size end faces of the first stage body and the second stage body are joined to form a double-stage body pin fin with a middle size smaller than the sizes at both ends; the large-size end face of the first stage body or the large-size end face of the second stage body is fixed on the heat dissipation area to form a heat conduction path.
[0006] Further, the pin-fin array in the heat dissipation area is formed by staggered arrangement of multiple rows of double-stage body pin fins.
[0007] Further, the shape of the first body is the same as that of the second body, the height of the first body is less than that of the second body, and the large-sized end face of the first body is fixed on the heat dissipation area; and / or, the taper of the first body is greater than that of the second body.
[0008] Further, the shape and size of the second body are the same as those of the first body.
[0009] Furthermore, when the first body is a frustum of a cone, the diameter of the small-sized end face of the frustum of the cone is greater than the radius of its large-sized end face.
[0010] Furthermore, when the first body is a frustum of an ellipse, along the major axis direction of the elliptical end face, the double frustum fin arrays are arranged in rows, and the center distance between a pair of double frustum fin arrays in adjacent odd rows or adjacent even rows is at least twice the length of the minor axis of the elliptical end face.
[0011] Furthermore, the center distance between a pair of double frustum fin arrays in adjacent odd columns or adjacent even columns is at least twice the length of the major axis of the elliptical end face.
[0012] Furthermore, when the first body is a frustum of a pyramid, the cross-section of the frustum of the pyramid is a rhombus or a regular polygon, and the axis of symmetry of the small-sized end face of the frustum of the pyramid is greater than one-half of the axis of symmetry of the corresponding large-sized end face.
[0013] Further, there are multiple heat dissipation areas, and the density of the fin arrays on the multiple heat dissipation areas increases sequentially along the fluid flow direction.
[0014] Furthermore, on each heat dissipation area, the outer end face shapes and sizes of the double frustum fins are the same; along the fluid flow direction, the tapers of the corresponding double frustum fins on the multiple heat dissipation areas increase sequentially.
[0015] Generally speaking, compared with the prior art by the above technical solutions conceived by the present application, the following beneficial effects are obtained: (1) The heat dissipation base plate provided by the present application includes a heat dissipation area, and the heat dissipation structure on the heat dissipation area is a fin array. Each heat dissipation fin in the fin array is a double frustum fin with a thin middle and thick ends. By optimizing the morphological structure and arrangement of the double frustum fins, the heat dissipation capacity of the heat dissipation base plate is improved, the weight of the heat dissipation base plate is reduced, and at the same time, the flow resistance and weight distribution of each heat dissipation area are balanced, realizing uniform temperature dissipation and uniform mass of the heat dissipation base plate.
[0016] (2) The double-cone fin structure provided by this application has a necking area that is thinner in the middle. When the fluid passes through the necking area in the middle of the double-cone, the flow velocity increases, forming local high-speed turbulence, breaking the thermal boundary layer, and enhancing the convective heat transfer coefficient. The size of the distal cone expands to slow down the flow velocity, increase the contact time between the fluid and the heat dissipation surface, and reduce the heat flow wake area. The cross-sections of the first and second cones in the double-cone fin are both designed with gradients, which can avoid the concentration of thermal expansion stress and reduce the thermal resistance. The surface area of the double-cone fin structure can be flexibly expanded by adjusting the heights of its first and second cones, achieving better heat dissipation performance than traditional structures, and is particularly suitable for scenarios with high power density and the need for lightweight.
[0017] (3) The double-cone fin structure provided by this application can be an asymmetric double-cone fin structure, that is, the heights of the two cones are different. The cone near the heat dissipation bottom plate has a larger taper, which can quickly contract to accelerate the fluid, strengthen the proximal heat transfer, and reduce the thermal resistance. The cone far from the heat dissipation bottom plate has a smaller taper, which can gently expand to reduce the pressure drop and extend the heat exchange time.
[0018] (4) The heat dissipation bottom plate provided by this application is designed with multiple heat dissipation areas, and the density of the fin arrays in the multiple heat dissipation areas increases along the fluid flow direction, so that the contact area between the fluid and the fin structure gradually increases, and thus the heat exchange area of this heat dissipation bottom plate gradually increases. The tapers of the corresponding double-cone fins in the multiple heat dissipation areas also gradually increase along the fluid flow direction to enhance turbulence and reduce the weight of a single double-cone fin.
[0019] (5) The collaborative design of the heat dissipation area layout, the end face size of the double-cone fin, and its row and column spacing in this application can effectively improve the heat dissipation efficiency of the heat dissipation bottom plate, balance the temperatures of each heat dissipation area, and also balance the flow resistance and weight distribution of each heat dissipation area, realizing uniform temperature heat dissipation and uniform mass of the heat dissipation bottom plate. Description of the Drawings
[0020] Figure 1 is a three-dimensional structural schematic diagram of the heat dissipation bottom plate of the power module provided in Embodiment 1 of this application; Figure 2 is a structural schematic diagram of the double-cone fin in the heat dissipation bottom plate provided in Embodiment 1 of this application; Figure 3 is a three-dimensional structural schematic diagram of the heat dissipation bottom plate of the power module provided in Embodiment 2 of this application; Figure 4 is a structural schematic diagram of the double-cone fin structure in different fin arrays provided in Embodiment 2 of this application; Figure 5 is a structural schematic diagram of the double-cone fin structure in different fin arrays provided in Embodiment 3 of this application; Figure 6 is a schematic diagram of one side structure of the heat dissipation bottom plate of the power module provided in Embodiment 3 of this application; Figure 7 It is a schematic diagram of the dimensions in the pin fin array 2a provided in Embodiment 3 of the present application; Figure 8 It is a schematic diagram of the dimensions in the pin fin array 2b provided in Embodiment 3 of the present application; Figure 9 It is a schematic diagram of the dimensions in the pin fin array 2c provided in Embodiment 3 of the present application; Figure 10 It is a three-dimensional structural schematic diagram of double truncated-cone pin fins with three different outer shapes provided in Embodiment 4 of the present application; Figure 11 It is a steady-state thermal simulation temperature distribution diagram of the upper surface of the heat dissipation base plate provided in Embodiment 3 of the present application; Figure 12 It is a steady-state thermal simulation temperature distribution diagram of the heat dissipation area on the lower bottom surface of the heat dissipation base plate provided in Embodiment 3 of the present application.
[0021] In all the drawings, the same reference numerals are used to represent the same elements or structures, where: 1 - Base plate body; 2 - Double truncated-cone pin fin, 21 - First truncated cone, 22 - Second truncated cone; 3 - Heat dissipation area. Specific embodiments
[0022] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.
[0023] The term "and / or" in this document is a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The symbol " / " in this document represents an "or" relationship between associated objects. For example, A / B represents A or B.
[0024] The terms "first" and "second" etc. in the description and claims of this document are used to distinguish different objects, rather than to describe the specific order of the objects. For example, the first response message and the second response message etc. are used to distinguish different response messages, rather than to describe the specific order of the response messages.
[0025] In the embodiments of the present application, words such as "exemplary" or "for example" are used to represent examples, illustrations or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or having more advantages than other embodiments or design solutions. Exactly speaking, using words such as "exemplary" or "for example" aims to present relevant concepts in a specific manner.
[0026] In the description of the embodiments of the present application, unless otherwise specified, "a plurality of" means two or more. For example, a plurality of processing units means two or more processing units, and a plurality of elements means two or more elements, etc.
[0027] The embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application.
[0028] Embodiment 1 The heat dissipation base plate of the power module provided by the present application includes a base plate body 1 and a pin fin array. As Figure 1 shown, a heat dissipation area 3 is provided on one surface of the base plate body 1, and the pin fin array is fixed on the heat dissipation area 3. The pin fin array includes a plurality of double-stage pin fins 2. The double-stage pin fin 2 includes a first stage 21 and a second stage 22. The shapes of the first stage 21 and the second stage 22 are both frustum cones, and the small-size end faces of the first stage 21 and the second stage 22 are joined together to form a double-stage pin fin 2 with a thin middle and thick ends. The large-size end face of the first stage 21 or the large-size end face of the second stage 22 is fixed on the heat dissipation area 3 to form a heat conduction path. Specifically, the pin fin array can be fixed on the heat dissipation area by welding, bonding, crimping or integral molding.
[0029] Specifically, in this embodiment, the pin fin array in the heat dissipation area 3 is formed by arranging multiple rows of double-stage pin fins in an interleaved manner to form a commutation surface, and a heat source power semiconductor chip is loaded on the back of the heat dissipation area 3 of the base plate body 1. Combining Figure 2 shown, the double-stage pin fins are symmetrically distributed with two stages up and down. The cross-sections of the first stage 21 and the second stage 22 are both elliptical, and the large-size end face of the first stage 21 is fixed on the heat dissipation area 3 in the middle of the base plate body 1 with a slight inward concavity.
[0030] The materials of the foregoing first stage 21 and second stage 22 are both high thermal conductivity materials (such as copper). The diameters of the small-size end faces of the first stage 21 and the second stage 22 in the double-stage pin fin are smaller than the radii of their respective large-size end faces, that is, the diameter of the necking area in the middle of the double-stage pin fin is greater than 0.5 times the outer end face diameter to avoid heat flow congestion.
[0031] Embodiment 2 The difference between this embodiment and Embodiment 1 is that, as Figure 3 shown, there are 3 heat dissipation areas 3, which are respectively denoted as 3a, 3b, and 3c. Each heat dissipation area has its own corresponding pin fin array 2a, pin fin array 2b, and pin fin array 2c, and the density of the pin fin arrays on the heat dissipation areas 3a, 3b, and 3c increases in sequence along the fluid flow direction. There are intervals between adjacent pin fin arrays. In this embodiment, the intervals include interval 4a and interval 4b, and the intervals 4a and 4b are used to make the water flow temperature mix evenly and enter the next heat dissipation area.
[0032] As shown Figure 4 in (a), (b) and (c) thereof, the tapers of the corresponding double-truncated-cone pin fins in the pin fin arrays 2a, 2b, and 2c are different, and the height of the first truncated cone 21 is the same as the height of the second truncated cone 22. Specifically, along the fluid flow direction, the multiple double-truncated-cone pin fins forming each pin fin array are exactly the same, but the taper angles of the double-truncated-cone pin fins corresponding to the different pin fin arrays 2a, 2b, and 2c α a 、α b 、α c decrease in sequence, that is α a >α b >α c , such that the tapers of the corresponding double-truncated-cone pin fins in the pin fin arrays 2a, 2b, and 2c increase in sequence from (a) to (c) in the figure, that is, the diameters of the reduced-diameter portions of the double-truncated-cone pin fins in different pin fin arrays decrease along the fluid direction in sequence, that is, L1 > L2 > L3. However, the heights of the double-truncated-cone pin fins in all pin fin arrays are the same, and the shapes and sizes of the end faces at both ends of the double-truncated-cone pin fins are also the same.
[0033] The above-mentioned structural design, layout design and dimension design of the double-truncated-cone pin fins can strengthen turbulent heat transfer. The flow velocity in the middle narrow area is significantly accelerated, the Reynolds number is increased, turbulence is induced and the thermal boundary layer is destroyed, and the convective heat transfer coefficient is increased. The flow velocity in the latter half of the truncated cone decreases, the contact time between the fluid and the heat dissipation surface is prolonged, and the energy loss in the wake area is reduced. At the same time, the gradient cross-sectional area of the double-truncated-cone pin fins can reduce the thermal resistance and achieve better heat dissipation performance than the traditional structure.
[0034] Example 3 The difference between this example and Example 1 is that, as shown Figure 5 in (a), (b) and (c) thereof, each double-truncated-cone pin fin is an asymmetric double-truncated-cone pin fin, and the shapes of both the first truncated cone 21 and the second truncated cone 22 are elliptical truncated cones, but the height of the first truncated cone 21 is less than the height of the second truncated cone 22.
[0035] Specifically, the heat dissipation base plate of the present embodiment also includes three heat dissipation zones, and the angle βa1, angle βb1 and angle βc1 of the corresponding double-stage pin-fins in the corresponding pin-fin arrays 2a, 2b and 2c in the three heat dissipation zones decrease successively, and βa2, βb2 and βc2 decrease successively, that is, the taper of the two stages constituting the double-stage pin-fins increases successively, so that βa1>βb1>βc1, βa2>βb2>βc2. The height of the first stage 21 close to the base plate body 1 in the pin-fin arrays 2a, 2b and 2c is relatively small, and the taper of the first stage 21 is designed to be relatively large, that is, βa1<βa2, βb1<βb2, βc1<βc2.
[0036] Specifically, Figure 6 As shown, the arrow indicates the water flow direction, which is also the length direction of the base body 1. Three heat dissipation areas 3a, 3b, 3c are distributed on the surface of the base body 1 along the water flow direction, and the density of the pin-fin array on each heat dissipation area increases successively along the fluid flow direction.
[0037] The three heat dissipation areas 3a, 3b, and 3c correspond to three power semiconductor chips respectively to dissipate heat for different chips. Water flows through the three heat dissipation areas 3a, 3b, and 3c in sequence, and removes the heat from the double-stage pin fins 2a, 2b, and 2c with different tapers, effectively improving the heat exchange efficiency. There is no pin fin array in the gaps 4a and 4b, which can effectively reduce the flow resistance without affecting the heat exchange area, so that the heat dissipation base has a good heat dissipation effect.
[0038] More specifically, the pin-fin arrays 2a, 2b, and 2c composed of multiple bi-platform pin-fins with different tapers are evenly arranged in the corresponding heat dissipation areas 3a, 3b, and 3c. In the heat dissipation area 3a, there are 6 bi-platform pin-fins in the odd-numbered rows and 5 bi-platform pin-fins in the even-numbered rows, and the odd-numbered rows and the even-numbered rows are staggered from top to bottom to form the pin-fin array 2a. In the heat dissipation area 3b, there are 6 bi-platform pin-fins in the odd-numbered rows and 6 bi-platform pin-fins in the even-numbered rows, which are staggered from top to bottom to form the pin-fin array 2b. In the heat dissipation area 3c, there are 6 bi-platform pin-fins in the odd-numbered rows and 6 bi-platform pin-fins in the even-numbered rows, which are staggered from top to bottom to form the pin-fin array 2c.
[0039] It is particularly noted that, in other embodiments, the number of double-stage pin wings in each row is not limited to the number in this embodiment, and can be set according to specific circumstances.
[0040] In this embodiment, the double-stage finned needles 2 are arranged in rows along the major axis direction of their elliptical end faces (i.e., the outer end faces) and in columns along the minor axis direction of their elliptical end faces. In each finned needle array, the center distance between a pair of double-stage finned needles distributed in adjacent odd rows or adjacent even rows is greater than or equal to twice the length of the minor axis of the elliptical end face. In each finned needle array, the center distance between a pair of double-stage finned needles 2 in adjacent odd columns or adjacent even columns is at least twice the length of the major axis of their elliptical end faces.
[0041] As Figure 7 shown, in the finned needle array 2a, the ratio of half of the center distance La2 between a pair of double-stage finned needles 2 distributed in adjacent odd columns or adjacent even columns to the major axis D of the elliptical end face is about 1.1. The center distance La1 between a pair of double-stage finned needles 2 distributed in adjacent odd rows or adjacent even rows is about 2.3 times the length of the minor axis d of the elliptical end face.
[0042] As Figure 8 shown, in the finned needle array 2b, the ratio of half of the center distance Lb2 between a pair of double-stage finned needles 2 distributed in adjacent odd columns or adjacent even columns to the major axis D of the corresponding elliptical end face is about 1.05, and the center distance Lb1 between a pair of double-stage finned needles 2 distributed in adjacent odd rows or adjacent even rows is about 2.15 times the length of the minor axis d of the elliptical end face.
[0043] As Figure 9 shown, in the finned needle array 2c, the ratio of half of the center distance Lc2 between a pair of double-stage finned needles 2 distributed in adjacent odd columns or adjacent even columns to the major axis D of the corresponding elliptical end face is about 1, and the center distance Lc1 between a pair of double-stage finned needles 2 distributed in adjacent odd rows or adjacent even rows is about 2 times the length of the minor axis d of the elliptical end face.
[0044] Perform a steady-state thermal simulation on the heat dissipation base plate provided in this embodiment. As Figure 11 and Figure 12 shown, in the legend on the left side of the figure, the temperature increases sequentially from blue to yellow. When the chip heat source power is 80w, from Figure 11 and Figure 12 the steady-state thermal simulation results, it can be seen that on the upper and lower surfaces of the heat dissipation base plate, as the fin density and double-stage taper in the heat dissipation area increase, the area of the high-temperature area (red area) on the surface where the chip is located and the area of the high-temperature area (red area) on the surface of the heat dissipation base plate facing away from the chip are significantly reduced, indicating that the heat dissipation effect of the heat dissipation base plate with this structure is significantly enhanced. Therefore, in this embodiment, along the cooling water flow direction, although the temperature increases, the layout with gradually increasing fin density and double-stage taper in the three heat dissipation areas enables the heat dissipation base plate to still achieve a good temperature uniformity effect.
[0045] Embodiment 4 In this embodiment, which is different from the foregoing Embodiments 1-3, the first body 21 is a frustum, and the second body 22 has the same shape and size as the first body 21. When the first body 21 is a frustum, the cross-section of the frustum is a rhombus or a regular polygon. As Figure 10 shown, its cross-section can be a rhombus, a square, or a regular hexagon in sequence, and can also be any other regular polygon that can be applied to this application. Moreover, the axis of symmetry of the small-sized end face of the frustum is greater than one-half of the axis of symmetry corresponding to it on the large-sized end face, which is also to weaken the heat flow congestion. In this embodiment, the frustum arrays are arranged in the most favorable manner for fluid flow and heat dissipation, such as being arranged in rows along the direction of a certain axis of symmetry of the rhombus or the regular polygon.
[0046] It should be understood that expressions such as "including" and "may include" used in this application indicate the existence of the disclosed functions, operations, or components, and do not limit one or more additional functions, operations, and components. In this application, terms such as "including" and / or "having" can be interpreted as indicating a specific characteristic, number, operation, component, component, or a combination thereof, but cannot be interpreted as excluding the existence or the possibility of adding one or more other characteristics, numbers, operations, components, components, or a combination thereof.
[0047] In addition, in this application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" can include A, can include B, or can include both A and B.
[0048] In the description of the embodiments of this application, it should be noted that unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Among them, "fixed connection" means that they are connected to each other and the relative positional relationship after connection remains unchanged. "Rotational connection" means that they are connected to each other and can rotate relative to each other after connection. "Sliding connection" means that they are connected to each other and can slide relative to each other after connection. The orientation terms mentioned in the embodiments of this application, such as "top", "bottom", "inside", "outside", "left", "right", etc., are only with reference to the direction of the drawings. Therefore, the orientation terms used are for better and clearer description and understanding of the embodiments of this application, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the embodiments of this application.
[0049] In addition, in the embodiments of the present application, mathematical concepts such as symmetry, equality, parallelism, and perpendicularity are mentioned. These limitations are all in view of the current technological level, rather than absolute strict definitions in the mathematical sense. A small deviation is allowed, and being approximately symmetric, approximately equal, approximately parallel, approximately perpendicular, etc. are all acceptable. For example, if A is parallel to B, it means that A is parallel to B or approximately parallel to B, and the included angle between A and B can be between 0 degrees and 10 degrees. If A is perpendicular to B, it means that A is perpendicular to B or approximately perpendicular to B, and the included angle between A and B can be between 80 degrees and 100 degrees.
[0050] As described above, the above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.
Claims
1. A heat dissipation base plate of a power module, characterized in that, It includes a base plate body (1) and a pin fin array. A heat dissipation area (3) is provided on the base plate body (1), and the pin fin array is fixed on the heat dissipation area (3); the pin fin array includes a plurality of double-stage pin fins (2), the double-stage pin fin (2) includes a first stage body (21) and a second stage body (22), the small-size end faces of the first stage body (21) and the second stage body (22) are joined together to form a double-stage pin fin (2) with a middle size smaller than the sizes at both ends; the large-size end face of the first stage body (21) or the large-size end face of the second stage body (22) is fixed on the heat dissipation area (3) to form a heat conduction path.
2. The heat dissipation base plate of a power module according to claim 1, characterized in that The pin fin array in the heat dissipation area (3) is formed by staggered arrangement of multiple rows of double-stage pin fins.
3. The heat dissipation base plate of a power module according to claim 1, characterized in that, The shape of the first stage body (21) is the same as that of the second stage body (22), the height of the first stage body (21) is smaller than the height of the second stage body (22), and the large-size end face of the first stage body (21) is fixed on the heat dissipation area (3); and / or, the taper of the first stage body (21) is greater than the taper of the second stage body (22).
4. The heat dissipation base plate of a power module according to claim 1, characterized in that, The second stage body (22) has the same shape and size as the first stage body (21).
5. The heat dissipation base plate of a power module according to claim 4, wherein, When the first stage body (21) is a frustum of a cone, the diameter of the small-size end face of the frustum of the cone is greater than the radius of its large-size end face.
6. The heat dissipation base plate of a power module as described in claim 4, wherein When the first stage body (21) is a frustum of an ellipse, along the long axis direction of the elliptical end face, the double-stage pin fins (2) are arranged in rows, and the center distance between a pair of double-stage pin fins (2) in adjacent odd rows or adjacent even rows is at least twice the length of the short axis of the elliptical end face.
7. The heat dissipation base plate of a power module according to claim 6, characterized in that, The center distance between a pair of double-stage pin fins (2) in adjacent odd columns or adjacent even columns is at least twice the length of the long axis of the elliptical end face.
8. The heat dissipation base plate of a power module according to claim 4, characterized in that When the first stage body (21) is a frustum of a pyramid, the cross-section of the frustum of the pyramid is a rhombus or a regular polygon, and the axis of symmetry of the small-size end face of the frustum of the pyramid is greater than one-half of the corresponding axis of symmetry on its large-size end face.
9. The heat dissipation base plate of a power module according to any one of claims 1-8, characterized in that, There are multiple heat dissipation areas (3), and the density of the pin fin arrays on the multiple heat dissipation areas (3) increases sequentially along the fluid flow direction.
10. The heat dissipation base plate of a power module according to claim 9, characterized in that, The shapes and sizes of the large-size end faces of the double-stage pin fins (2) on the multiple heat dissipation areas (3) are the same, and along the fluid flow direction, the tapers of the double-stage pin fins (2) on the multiple heat dissipation areas (3) increase sequentially.