Power module heat dissipation bottom plate and manufacturing method thereof

Abstract

The invention provides a power module heat dissipation base plate and a manufacturing method thereof, the power module heat dissipation base plate comprises a heat dissipation base plate and a cooling flow channel system formed in the heat dissipation base plate, the cooling flow channel system comprises a plurality of flow channel units, and the flow channel units are arranged in an asymmetrical mode by utilizing bending structures and wing-shaped structures of internal channels of the flow channel units. And the flow resistance of the cooling medium during forward flowing is lower than that during reverse flowing, so that directional flowing and enhanced heat exchange of the cooling medium are realized. According to the invention, accurate heat dissipation can be carried out on the hot spot area of the power module, local overheating and reliability reduction are avoided, the heat exchange capability of the flow channel is improved, and the effect of controllable flow of the cooling medium is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to a power module heat dissipation base plate and a manufacturing method thereof. BACKGROUND

[0002] With the development of power module to high power density, the performance of its heat dissipation system is required to be the best. The existing heat dissipation base plate and its manufacturing process are facing a bottleneck: on the one hand, the traditional straight channel or simple curved channel cannot realize the efficient directional flow and heat exchange enhancement of the cooling medium in function, resulting in the ceiling of the heat dissipation performance; on the other hand, from the system design point of view, the existing scheme lacks effective response to the uneven heating characteristics of the power module, and cannot realize accurate partition temperature management. More importantly, limited by the traditional manufacturing process, it is difficult to economically and reliably process the internal flow channel with complex three-dimensional asymmetric structure, which seriously restricts the innovation of heat dissipation design. Therefore, one of the purposes of the present application is to provide a heat dissipation base plate with significantly improved heat dissipation performance, and the other purpose is to provide an advanced manufacturing method of the heat dissipation base plate. SUMMARY

[0003] The present application provides a power module heat dissipation base plate and a manufacturing method thereof, which can effectively solve the above problems.

[0004] The present application is implemented as follows: A power module heat dissipation base plate, comprising a heat dissipation base plate and a cooling flow channel system formed in the interior thereof, the cooling flow channel system comprising a plurality of flow channel units, the flow channel units utilizing the asymmetric arrangement of the bending structure and the wing-like structure of the internal channel to make the flow resistance of the cooling medium in the forward flow lower than that in the reverse flow, thereby realizing the directional flow and enhanced heat exchange of the cooling medium. The interior of the heat dissipation base plate is divided into at least one first region and one second region with different heat dissipation requirements based on the heat source distribution pattern of the power module connected thereto, and the distribution parameters of the flow channel units in the first region are different from those in the second region.

[0005] A manufacturing method of a power module heat dissipation base plate, comprising the following steps: S1, based on the heat source distribution and heat dissipation requirement of the power module, constructing a three-dimensional model of the heat dissipation base plate containing a plurality of flow channel units by a three-dimensional modeling software; S2, using a metal additive manufacturing equipment, melting metal powder layer by layer according to the three-dimensional model, and integrally forming the green body of the heat dissipation base plate; S3, heat treating the green body of the heat dissipation base plate and finishing the inner surface of the flow channel.

[0006] The present application has the following beneficial effects: (1) The unique structure of the flow channel unit enables one-way acceleration flow of the cooling medium in the flow channel, increasing the heat exchange efficiency of the cooling medium and the heat dissipation base plate. Compared with traditional heat dissipation base plates, the heat dissipation efficiency can be increased by about 30%-50%. For example, under the same power module heating conditions, the temperature of the power module using the flow channel unit heat dissipation base plate can be reduced by 5-10℃, effectively improving the working performance and stability of the power module.

[0007] (2) By setting the flow channel of the flow channel unit in different zones and distributing the flow according to the heating conditions of the power module, uniform heat dissipation of different areas of the power module can be achieved, and the temperature of the hot spot area can be reduced to the same level as other areas, with a temperature difference of within 2-3℃, greatly improving the overall reliability of the power module and reducing the risk of failure caused by local overheating.

[0008] (3) The one-way conduction characteristic of the flow channel unit can effectively prevent backflow and turbulence of the cooling medium, keeping the cooling medium in stable one-way flow in the flow channel. This not only improves the stability of the heat dissipation effect, but also reduces the impact and vibration of the cooling medium flow on the heat dissipation base plate structure, prolonging the service life of the heat dissipation base plate. Under different working conditions, such as changes in cooling liquid flow or pressure, the flow direction of the cooling medium can still remain stable, without reverse flow or turbulence, ensuring the normal operation of the heat dissipation system.

[0009] (4) The adjustability of the flow channel unit structure allows the heat dissipation base plate to be flexibly designed and optimized according to different power module specifications, heat dissipation requirements, and application scenarios. Without the need for large-scale redesign and manufacturing, only by adjusting the geometric parameters and flow channel layout of the flow channel unit, new heat dissipation requirements can be quickly met, reducing research and development costs and time costs, and improving the market competitiveness of the product.

[0010] (5) Using micro-nano processing technology or 3D printing technology to manufacture the heat dissipation base plate can realize precise manufacturing of complex flow channel unit structures, ensuring the consistency and reliability of the product. At the same time, these manufacturing processes have high production efficiency and flexibility, suitable for mass production and customized manufacturing, and can meet the needs of different customers. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0012] Figure 1is a front view of the present invention.

[0013] Figure 2 is a flow chart of the manufacturing method of the present invention. Figure 1 is an enlarged view of A in the present invention.

[0014] Figure 3 is a flow chart of the manufacturing method of the present invention. DETAILED DESCRIPTION

[0015] For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some but not all of the embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but only represents selected embodiments of the present invention.

[0016] In the description of the present invention, the terms "first", "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0017] Referring to Figures 1-3 As shown in the drawings, a power module heat dissipation base plate includes a heat dissipation base plate 10 and a cooling flow channel system formed in the interior thereof; the interior of the heat dissipation base plate 10 is divided into at least a first region and a second region with different heat dissipation requirements based on the heat source distribution pattern of the power module connected thereto, and the distribution parameters of the flow channel units 40 in the first region are different from those in the second region. The material of the heat dissipation base plate 10 is pure copper or aluminum alloy.

[0018] Specifically, the heat dissipation base plate 10 is provided with a main cooling liquid inlet 20 and a plurality of threaded holes 30, and an internal cooling liquid flow channel system is formed, which is composed of a plurality of flow channel units 40 connected in parallel or series. The flow channel unit 40 includes at least one curved channel structure and a first wing structure 404 and a second wing structure 406 arranged in the channel structure, and the first wing structure 404 and the second wing structure 406 are fixedly connected to the side wall of the channel and protrude into the flow channel cavity. The channel structure includes a first channel 400 and a second channel 402 connected to each other, the first channel 400 is provided with the first wing structure 404, the second channel 402 is provided with the second wing structure 406, and the first wing structure 404 and the second wing structure 406 are asymmetrically distributed in the flow channel.

[0019] Further, it is worth noting that the core function of the flow channel unit 40 is its direction-dependent flow resistance, and its working principle can be explained as follows in combination with fluid dynamics: Forward flow (low flow resistance path): when the cooling medium flows in the designed direction (for example, from the first channel 400 to the second channel 402), the first wing structure 404 and the second wing structure 406 play a role of guiding flow, they can smoothly guide the fluid, so that the main flow line can pass through the curved channel relatively smoothly, at this time, the fluid energy loss is small, which shows a low system flow resistance; reverse flow (high flow resistance path): when the cooling medium tries to flow in the reverse direction, the function of the wing structure changes from "flow guiding" to "flow resistance", and the asymmetrically arranged wing structure will directly guide the fluid to the channel wall, in cooperation with the curved channel, it will cause large-scale separation and severe vortex of the fluid, these vortexes will consume a large amount of fluid kinetic energy, forming a large local pressure drop, thereby producing a strong inhibition effect on the reverse flow, which is equivalent to integrating an invisible "fluid diode" in the flow channel, effectively eliminating the harmful backflow that may be caused by system pressure fluctuation, and ensuring the efficient forward movement of the cooling medium along the predetermined path.

[0020] More specifically, the flow channel unit 40 is not only a flow controller, but also a high-efficiency heat transfer enhancer. Even in the forward flow, the flow line of the fluid will be forced to change direction continuously when flowing through the curved channel and the asymmetric wing structure, generating continuous secondary flow and micro-vortex. This strong disturbance effectively destroys the thermal boundary layer near the flow channel wall, which is the main resistance layer of heat transfer. At the same time, the curved and elongated flow channel path itself increases the contact area and contact time of the cooling medium with the flow channel wall. Combined with the above flow field disturbance, the cooling liquid can more fully flush the flow channel wall, thereby greatly enhancing the convective heat transfer efficiency and removing the heat generated by the power module more quickly. Through the triple effects of "directional flow guiding + anti-backflow + flow field disturbance", the integrated flow channel unit 40 realizes the one-way, efficient and stable flow and heat transfer of the cooling medium.

[0021] The inner part of the first channel 400 and the second channel 402 are both provided with a guide vane 408; the guide vane 408 is at an angle of 15°-20° with the main flow direction. In one embodiment, in order to further optimize the efficiency of the forward flow and overcome the additional flow resistance inevitably introduced by the wing-shaped structure when creating high unidirectionality, the present application innovatively introduces a guide vane 408 at an angle of 15°-20° with the main flow direction in the channel. The guide vane 408 tilted at a small angle of 15°-20° can smoothly "cut into" and guide the main flow, making it more closely adhere to the inner wall of the channel. This phenomenon utilizes the "Coanda effect" of fluid, i.e. fluid tends to flow along the adjacent wall. By actively shaping the flow lines in this way, the guide vane 408 effectively suppresses the separation phenomenon of fluid at the bending part of the channel due to inertia, avoiding the generation of large-scale and high-energy consumption vortex. At the same time, by suppressing flow separation, the guide vane 408 greatly reduces the friction and vortex dissipation between the fluid and the separated area of the wall, which makes the cooling medium flow more smoothly in the forward direction with less pressure loss. The direct benefit is that under the same pumping power, a higher flow rate of cooling liquid can be obtained, or to achieve the same flow rate, the requirement for system pumping capacity can be reduced, thereby improving system energy efficiency. In addition, although the main purpose of the guide vane 408 is to reduce flow resistance, it also optimizes the flow velocity distribution. It ensures that the cooling medium can sweep the entire flow passage wall at a high and uniform speed, which helps to thin the thermal boundary layer and strengthen the convective heat transfer coefficient. Therefore, it not only does not weaken the heat transfer effect, but also synergistically enhances the heat transfer effect while reducing the flow resistance.

[0022] More preferably, the projection position of the guide vane 408 in the longitudinal direction of the flow passage partially overlaps or is closely adjacent to the projection position of the nearest wing-shaped structure 404, 406. This spatial layout ensures that the vortex generated from the wing-shaped structure can be timely guided and reorganized by the guide vane, thereby stabilizing the flow field faster without sacrificing the vortex intensity (i.e. heat transfer performance), realizing the'synergistic effect' of low pressure loss and high heat transfer, rather than a simple performance compromise.

[0023] More specifically, the main responsibility of the asymmetric wing structures 404, 406 in the flow channel unit 40 is to create a large positive and negative flow resistance difference, that is, to achieve a strong "diode" effect (anti-backflow) and to enhance heat exchange by turbulence, while the responsibility of the guide vanes 408 is to "fine-tune" the positive flow on this basis, making up for the part of the additional energy loss inevitably brought by the wing structure when disturbing the flow field, both of which work together to produce the technical effect of "high unidirectionality, high heat exchange, and low positive flow resistance". Furthermore, without the guide vanes 408 of the flow channel unit 40, although the unidirectionality is good, the positive flow resistance may still be relatively high, limiting its flow and application potential in actual systems. After adding the guide vanes 408 with precisely optimized angles, while maintaining its excellent anti-backflow ability and high heat exchange performance, its positive flow efficiency is improved to a level that can be put into practical engineering applications.

[0024] In summary, the guide vanes 408 tilted at 15°-20° act as "coordinators" inside the flow channel unit, optimizing the positive flow performance by guiding flow lines and suppressing separation, complementing the functions of the wing structures, and together pushing the flow channel system of the heat dissipation base plate towards the ideal state of high efficiency, controllability, and low consumption.

[0025] It should be noted that the protruding directions of the first wing structure 404 and the second wing structure 406 form an angle of 30°-60° with the side walls of the channel. In one embodiment, if the angle is too small, the wing structure is too "flat" against the wall, and its disturbance effect on the fluid is insufficient. In both positive and negative flow, it is more like a gentle guide vane 408, which cannot produce a significant enough flow resistance difference, resulting in a weak "fluid diode" effect. If the angle is too large, the wing structure is too "upright", which will act as a large obstacle in positive flow, causing excessive wind resistance and leading to a sharp increase in positive flow resistance, which is contrary to the original intention of reducing positive flow resistance. Therefore, within the range of 30°-60°, the wing structure can achieve dynamic flow control. Specifically, the angle of 30°-60° ensures that the wing structure has sufficient projected area and angle of attack to effectively "cut" the fluid, which forcibly changes the momentum direction and velocity distribution of the fluid when it flows through, no longer being a laminar smooth flow, but generating a wide range of strong turbulence and secondary flow. This strong disturbance is the physical basis for breaking the thermal boundary layer and enhancing heat exchange.

[0026] More specifically, the flow channel unit 40 is different from a simple curved pipe in that it has an internal asymmetrically arranged wing structure. It is this wing structure that is arranged at a specific angle that turns a passive flow channel into an active, directionally identifiable and flow field activated intelligent fluid element. The one-way flow capacity, anti-backflow characteristics and most of the heat exchange enhancement effect of the entire heat dissipation base plate are directly derived from the microscopic work of the wing structure in each flow channel unit, which is the key bridge that converts fluid dynamics principles into practical engineering performance.

[0027] In summary, through the above asymmetric flow resistance, the cooling system can efficiently guide the cooling medium to flow along the designed path and naturally inhibit harmful backflow and flow instability, which ensures the reliability and stability of the heat dissipation process. The wing structure is a "turbulence generator" in the flow field, which continuously stirs the lower-temperature fluid in the center of the flow channel to the high-temperature wall, while the heated boundary layer fluid is rolled into the main flow. This process greatly thins and destroys the thermal boundary layer that hinders heat transfer, allowing heat to be more efficiently transferred from the flow channel wall to the cooling medium, significantly improving heat exchange efficiency. Furthermore, the flow channel unit 40 can still maintain its one-way and high heat exchange performance when the cooling liquid flow or pressure fluctuates, demonstrating good robustness. The width of the channel structure is 0.5mm to 2.0mm, and the wall thickness between adjacent flow channels is 0.3mm to 1.0mm; the inner wall of the channel structure is covered with a polytetrafluoroethylene coating. Further, the flow channel width (W) of the flow channel unit 40 and the wall thickness (T) between adjacent flow channels are related to each other. Specific embodiments are as follows: Example One: Wide flow channel design suitable for high heat density areas For the key heat dissipation area of the chip set in the power module, the flow channel width (W) of the internal flow channel unit 40 is preferably set to 1.5mm to 2.0mm. For example, in a Z-shaped unit, the width of the first channel 400 and the second channel 402 is within this range. Correspondingly, to ensure the integrity of the structure under high-pressure cooling liquid impact, the wall thickness (T) between adjacent flow channels is set to 0.8mm to 1.0mm. This is because a wider flow channel can effectively reduce the flow resistance and increase the flow rate of the cooling medium, thereby quickly removing the large amount of heat concentrated in this area. A thicker wall thickness ensures that this high heat dissipation load area has sufficient mechanical strength and pressure resistance.

[0028] Example Two: Compact flow channel design suitable for ordinary areas For the common heat dissipation area in the power module with low heat generation, the flow channel width (W) of the flow channel unit 40 can be designed to be 0.5-1.0 mm. The wall thickness (T) between adjacent flow channels can be correspondingly reduced to 0.3-0.5 mm. This is because narrower flow channels and thinner wall thickness allow a higher density of flow channel networks to be arranged in a limited space, thereby increasing the total heat exchange area. Although the single flow channel flow is reduced, the quantity advantage is achieved, which realizes efficient and balanced heat dissipation for the area, while realizing the lightweight and compactness of the heat dissipation base plate.

[0029] In a preferred embodiment, the flow channel unit 40 is in a Z-shaped layout. The center line total length of the first channel 400 and the second channel 402 is 15 mm, and the curvature radius of the bending part is 1.5 mm. The first wing-shaped structure 404 is at an angle of 45° with the channel wall, and the length is 0.5 mm; the second wing-shaped structure 406 is at an angle of 60°, and the length is 0.3 mm. The specific configuration is verified by CFD simulation, and the forward flow resistance coefficient is X, the reverse flow resistance coefficient is Y, and the forward and reverse flow resistance ratio reaches Z, which exhibits the one-way valve effect.

[0030] To improve the reliability and heat dissipation efficiency of long-term use, the inner wall of the flow channel is specially treated. The specific implementation includes: Example A: PTFE coating A layer of polytetrafluoroethylene coating is coated on the inner wall of the flow channel by spraying or dipping process, and the coating thickness is controlled to be 0.1-0.3 mm. Polytetrafluoroethylene has extremely low surface energy and extremely low friction.

[0031] Technical effect: The non-stick and lubricating properties of the polytetrafluoroethylene coating make the cooling medium flow more smoothly, which can further reduce the pressure drop of the entire flow channel system, cooperate with the optimized design of the flow channel unit, and effectively resist the chemical corrosion of various cooling liquids (especially water-based cooling liquids), protect the metal flow channel substrate, and provide electrical insulation to improve system safety.

[0032] Example B: Metal functional plating For applications that pursue extreme thermal conductivity performance, a thin layer of silver or gold plating can be applied on the inner wall of the flow channel after nickel plating. The total thickness of the metal plating is controlled to be 0.05-0.2 μm.

[0033] Technical effect: Silver or gold has extremely high thermal conductivity, and this ultra-thin plating layer can reduce the contact thermal resistance between the flow channel wall and the cooling liquid, which is like building a heat-conducting road, so that heat can be transferred to the cooling liquid more quickly. At the same time, the dense noble metal plating layer can effectively prevent the oxidation of the copper or aluminum alloy flow channel substrate, maintaining its long-term stable heat dissipation performance.

[0034] Wherein, the distribution parameter is the unit density. The cooling liquid flow channel system inside the heat dissipation base plate 10 includes a high-density area and a low-density area with different unit densities.

[0035] Specifically, the area division is not subjective, but based on the accurate analysis of the heat power density and spatial layout of each element inside the power module (such as IGBT chip, diode, etc.), usually through thermal simulation analysis software or with the help of thermal imaging technology in actual testing, to obtain the detailed temperature field distribution diagram of the power module in working state, so as to identify the high heat flux density area (i.e. "hot spot") and the area with relatively low heat generation. In the design stage of the heat dissipation base plate 10, the above thermal analysis results are spatially mapped, and the area on the heat dissipation base plate 10 corresponding to the position of the "hot spot" of the power module is designated as the first area (key heat dissipation area) of the present application; while the area corresponding to the low heat generating element is designated as the second area (ordinary heat dissipation area). Therefore, in the specific implementation of the present scheme, the "distribution parameter" of the flow channel unit 40 in different areas is adjusted to realize differentiated heat dissipation capacity. The core distribution parameter is "unit density", that is, the number of flow channel units 40 distributed per unit area. Specifically, the number of flow channel units 40 per unit area in the first area is 30% to 50% more than that in the second area. This is because a higher unit density means that the total inner surface area of the cooling flow channel system in the first area is larger, providing more channels for heat transfer from the base plate to the cooling liquid, and the dense flow channel network forms a path with relatively low flow resistance in the first area (although the unit itself has flow resistance, but the number of parallel channels increases), the system will automatically guide a larger proportion of cooling medium flow to this area, and the more complex flow channel network will prolong the residence time of the cooling medium in the first area, allowing it to have more time for heat exchange with the flow channel wall, thereby more effectively removing heat. In order to further enhance the effect of partitioned heat dissipation and prevent thermal interference between areas, the present application also adopts the following collaborative design: A heat insulation structure is arranged between the first area and the second area, and the material of the heat insulation structure is ceramic fiber or aerogel. Specifically, the high-density area (first area) and the low-density area (second area) are separated by a solid heat insulation wall, and the thickness of the solid heat insulation wall is 0.5mm to 1.0mm. Its role is to block or significantly reduce the lateral conduction (thermal diffusion) of heat from the high-temperature first area to the low-temperature second area, forcing heat to be mainly conducted vertically upward and taken away by the cooling flow channel above, thereby ensuring that cooling resources can be concentrated for cooling the "hot spot" that needs heat dissipation the most.

[0036] More specifically, the above-mentioned division of areas has clear quantitative standards and scientific basis. Specifically, the first area (key heat dissipation area) refers to the steady-state heat flux density of the corresponding projection area of the power module connected thereto when the power module is working, which exceeds 100 W / cm2 The first region (high heat flux region) refers to the region corresponding to the concentrated installation position of the core chips such as IGBT or MOSFET in the power module. Conversely, the second region (ordinary heat dissipation region) refers to the region whose steady-state heat flux density corresponding to the projected region is less than 50 W / cm 2 The second region (ordinary heat dissipation region) refers to the region whose steady-state heat flux density corresponding to the projected region is less than 50 W / cm

[0037] Further, in order to realize smooth transition of heat dissipation capacity and avoid flow field instability or local stress concentration caused by sudden change of flow channel layout, the distribution of the flow channel units 40 is optimized. The surface density of the flow channel units 40 decreases gradually from the first region to the second region. In other words, at the junction of the first region and the second region, there is a transition zone, in which the unit density decreases smoothly and continuously from the high value of the first region to the low value of the second region, rather than suddenly changing in steps. This gradient design helps to maintain the stability of the cooling medium pressure and the flow field, and at the same time improves the structural stress distribution of the heat dissipation base plate under the change of temperature field. Therefore, through the above accurate partitioning based on heat flux density and the gradient design of density, the heat dissipation base plate 10 of the present application realizes intelligent spatial allocation of cooling resources. According to the results of computational fluid dynamics simulation, under typical working conditions, about 60% to 70% of the total cooling liquid flow will be automatically allocated and flow through the first region (high heat dissipation region). This flow self-distribution feature ensures that the limited cooling capacity is preferentially and concentratedly used for the "hot spot" region with the most urgent heat dissipation demand, thereby achieving the best balance between heat dissipation efficiency and uniformity at the system level. Experimental data show that, compared with the unpartitioned uniform flow channel design, the maximum junction temperature of the power module can be reduced by more than 15℃, and the temperature difference (ΔTj) between the chips can be reduced to within 10℃. The specific experimental data are shown in the following table:

[0038] As shown in the above experimental data, compared with the traditional unpartitioned uniform flow channel, the partitioned flow channel unit heat dissipation base plate of the present application exhibits excellent comprehensive heat dissipation performance: Wherein, the maximum junction temperature is significantly reduced from 98.5°C to 81.2°C, with a reduction of 17.3°C. This data fully proves that the scheme of the application can effectively cope with high heat density, greatly reducing the risk of power module failure due to overheating; the maximum junction temperature difference is sharply reduced from 25.7°C to 7.5°C, with a reduction of 18.2°C. This strongly confirms that the partitioned heat dissipation design of the application successfully realizes "on-demand heat dissipation", significantly improving the uniformity of the internal temperature of the power module, which is crucial for synchronously improving the reliability and life of all chips; and the average heat exchange coefficient of the hot spot area is increased by 84%, which directly verifies that the flow channel unit through the "directional flow guiding, anti-backflow, flow field disturbance" triple effect, the heat exchange process is extremely enhanced. While achieving the above-mentioned great temperature control benefits, the system flow resistance is only increased by 3.7 kPa. This shows that through the flow guide piece 408 and the flow channel design, the application successfully minimizes the negative impact of the inherent flow resistance of the flow channel unit, with a small pumping power, the heat dissipation performance is improved, and the overall energy efficiency ratio is greatly optimized.

[0039] Further, for the partition design, the application is further illustrated by the following embodiments: I. Object and problem definition: An IGBT power module with a rated power of 30kW is taken as the heat dissipation object. The heat distribution of multiple chips inside the module is extremely uneven during operation. Through thermal-flow coupling simulation analysis, it is determined that the two core chips located at the geometric center of the module generate most of the heat, with a heat flux density of 120 W / cm 2 and 115 W / cm 2 respectively, forming a significant hot spot, while the heat flux density of the auxiliary circuit and the connection area around the module is lower than 45 W / cm 2 . II. Partition mapping and design: Based on the above thermal analysis results, in the three-dimensional design model of the heat dissipation base plate 10, accurate spatial mapping is performed: the first area (key heat dissipation area): defined as the area completely coinciding with the projection position of the above two high heat flux density chips; the second area (ordinary heat dissipation area): defined as the peripheral area on the heat dissipation base plate with a heat flux density lower than 45 W / cm 2 . To achieve targeted heat dissipation, the flow channel unit 40 layout of the two areas is designed differently: in the first area, a higher flow channel unit surface density of 12 / cm 2 is set. At the same time, the average width of the flow channel in this area is set to 1.8mm to ensure greater cooling medium flow capacity per unit time; in the second area, a relatively lower flow channel unit surface density of 8 / cm 2The average width of the flow channel in the region is set to 1.0 mm to achieve a compact layout and sufficient heat exchange area. To achieve a smooth transition of heat dissipation capacity and avoid flow field and stress mutations, a transition zone with a width of 3 mm is designed at the junction of the first region and the second region. In this transition zone, the surface density of the flow channel unit decreases linearly from 12 units / cm 2 in the first region to 8 units / cm 2 .

[0040] Therefore, the designed model is subjected to computational fluid dynamics simulation verification, and the results show that: due to the lower flow resistance path formed by the denser flow channel network in the first region, the system automatically allocates and converges about 65% of the total coolant flow to the first region, achieving "on-demand allocation" of cooling resources. At the same time, under the condition of 30kW full load working state, the highest temperature of the first region where the heat is most concentrated is successfully controlled below 85℃, and the power module as a whole shows excellent temperature uniformity, and the average temperature difference between the first region and the second region is reduced to within 8℃. Compared with the traditional design without zoning and using uniform flow channel density, the maximum junction temperature of the power module is reduced by more than 18℃, and the temperature gradient between chips is significantly reduced, which greatly alleviates the risk of material thermal stress and fatigue failure caused by local overheating and thermal expansion mismatch, thereby significantly improving the long-term operation reliability and service life of the power module.

[0041] To further realize intelligent control, a flow regulating device is arranged at the outlet of the cooling flow channel of the first region, and the flow regulating device is communicatively connected to a control system and adjusts the flow of the cooling medium through the region based on real-time temperature feedback of the first region. Specifically, the device is composed of a miniature electric regulating valve and a temperature sensor, which monitors the temperature of the region in real time and feeds back the signal to the control system, which dynamically adjusts the opening of the miniature electric regulating valve according to the preset temperature threshold. When the temperature of the first region is too high, the opening is increased to allow more coolant to flow through to enhance heat dissipation; when the temperature is normal, the opening is appropriately reduced to optimize the system's pumping power consumption. This makes the heat dissipation system have self-adaptive ability, further improving the heat dissipation uniformity and energy efficiency.

[0042] The cooling flow channel system includes a plurality of flow channel units 40, which utilize the asymmetric arrangement of the curved structure and wing-like structure of the internal passage to make the flow resistance of the cooling medium lower when flowing forward than when flowing backward, thereby realizing directional flow and enhanced heat exchange of the cooling medium.

[0043] The inner surface of the flow channel of the flow channel unit 40 is provided with a metal plating layer or a polymer coating.

[0044] A manufacturing method of a power module heat dissipation bottom plate, comprising the following steps: S1, based on the heat source distribution of the power module and the heat dissipation demand, a three-dimensional model of the heat dissipation base plate containing multiple flow channel units 40 is constructed through a three-dimensional modeling software; S2, an integral green body of the heat dissipation base plate is formed by layer-by-layer melting of metal powder according to the three-dimensional model using a metal additive manufacturing equipment; S3, heat treatment is performed on the green body of the heat dissipation base plate, and the inner surface of the flow channel is finished.

[0045] In the S1 step, the high heat flux density area of the power module is determined through thermal simulation analysis, and the flow channel units 40 with higher distribution density are set in the corresponding high heat flux density area in the three-dimensional model. Specifically, the area with steady-state heat flux density exceeding 100 W / cm 2 is defined as the key heat dissipation area, and the area with heat flux density lower than 50 W / cm 2 is defined as the ordinary heat dissipation area. Based on the above analysis, parameterized modeling is performed using professional three-dimensional modeling software, and the model accuracy is controlled within 0.01 mm. In the key heat dissipation area in the model, the distribution density of the flow channel units 40 is set to be significantly higher, for example, the number of units per unit area is 30% to 50% higher than that in the ordinary heat dissipation area. At the same time, the degree of bending or the total length of the flow channel in this area can be appropriately increased to further prolong the residence time of the cooling medium.

[0046] In the S2 step, the process parameters used include: laser power 200 W to 400 W, scanning speed 800 mm / s to 1500 mm / s, powder layer thickness 30 μm to 50 μm. The main material of the heat dissipation base plate 10 is selected from high thermal conductivity metals. For high-power application scenarios, copper powder with purity ≥ 99.5% (such as CuCrZr) is preferred, which has a thermal conductivity of about 386 W / (m·K); for weight-sensitive application scenarios, aluminum alloy powder such as AlSi10Mg is selected, which has a thermal conductivity of 180-230 W / (m·K), and chessboard scanning or spiral scanning is used to disperse and reduce thermal stress, reduce part deformation, print under inert gas protection, and monitor the molten pool state through a real-time monitoring system to timely detect defects such as pores and cracks.

[0047] In the S3 step, the finishing is electrochemical polishing, and the polishing parameters include: electrolyte temperature 40℃ to 60℃, current density 10A / dm 2 to 30A / dm 2, polishing time 10 minutes to 30 minutes. At the same time, the green body is stress relief annealing, for aluminum alloy parts, at 300℃ - 500℃ for 1 - 3 hours, then furnace cooling, to eliminate internal stress, stable size and improve material toughness, and the parts are separated from the substrate by wire cutting, and the internal residual powder is thoroughly removed, through the above processing, the roughness (Ra) of the inner surface of the flow channel can be significantly reduced from 5-10μm after printing to 0.1μm - 0.5μm, thereby greatly reducing the flow resistance and strengthening the heat exchange efficiency.

[0048] In step S3, for further performance improvement, the inner wall of the flow channel can be surface treated, including nickel plating followed by silver / gold plating treatment, the total thickness of the metal plating layer is controlled at 0.05μm - 0.2μm, to establish super heat conduction band and prevent oxidation, or, through spraying or dipping process to coat polytetrafluoroethylene coating, the coating thickness is between 0.1mm - 0.5mm, and high temperature curing, the coating can effectively reduce the flow resistance and prevent cooling liquid corrosion, finally, fill the ceramic fiber or aerogel in the reserved heat insulation wall cavity and solidify. Finally, endoscopy, pressure test and other methods are used for final inspection.

[0049] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A power module heat dissipation base plate, comprising a heat dissipation base plate (10) and a cooling channel system formed therein, characterized in that, The cooling channel system includes multiple channel units (40). The channel units (40) utilize the asymmetrical arrangement of the curved structure and wing-shaped structure of their internal channels to make the flow resistance of the cooling medium lower when it flows in the forward direction than when it flows in the reverse direction, thereby realizing the directional flow of the cooling medium and enhancing heat transfer. The interior of the heat dissipation base plate (10) is divided into at least one first region and a second region with different heat dissipation requirements based on the heat source distribution pattern of the power module connected thereto. The distribution parameters of the flow channel unit (40) in the first region are different from those in the second region.

2. The power module heat dissipation base plate according to claim 1, characterized in that, The distribution parameter is the cell density; The number of flow channel units (40) per unit area in the first region is 30% to 50% more than that in the second region.

3. The power module heat dissipation base plate according to claim 1, characterized in that, A heat insulation structure is provided between the first region and the second region, and the material of the heat insulation structure is ceramic fiber or aerogel.

4. A power module heat dissipation base plate according to claim 1, characterized in that, A flow regulating device is provided at the outlet of the cooling channel in the first region. The flow regulating device is communicatively connected to a control system and adjusts the flow rate of the cooling medium flowing through the region based on the real-time temperature feedback of the first region.

5. A power module heat dissipation base plate according to claim 1, characterized in that, The inner surface of the flow channel unit (40) is provided with a metal plating or polymer coating.

6. A method for manufacturing a heat dissipation base plate for a power module as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Based on the heat source distribution and heat dissipation requirements of the power module, a three-dimensional model of the heat dissipation base plate containing multiple flow channel units (40) is constructed using three-dimensional modeling software. S2. Using metal additive manufacturing equipment, metal powder is melted layer by layer according to the three-dimensional model to integrally form the heat dissipation base plate blank; S3. Perform heat treatment on the heat dissipation base plate blank and finish the inner surface of the flow channel.

7. The method for manufacturing a power module heat dissipation base plate according to claim 6, characterized in that, In step S2, the process parameters used include: laser power of 200W to 400W, scanning speed of 800mm / s to 1500mm / s, and powder layer thickness of 30μm to 50μm.

8. The method for manufacturing a power module heat dissipation base plate according to claim 6, characterized in that, In step S3, the finishing process is electrochemical polishing, with polishing parameters including: electrolyte temperature 40°C to 60°C, and current density 10 A / dm³. 2 Up to 30A / dm 2 Polishing time is 10 to 30 minutes.

9. A method for manufacturing a power module heat dissipation base plate according to claim 6, characterized in that, In step S1, the high heat flux density region of the power module is determined by thermal simulation analysis, and the flow channel unit (40) with a higher distribution density is set in the corresponding high heat flux density region in the three-dimensional model.

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