A high-efficiency heat dissipation structure suitable for high-power-density SiC power devices

Abstract

The application belongs to the technical field of heat dissipation, and discloses a high-efficiency heat dissipation structure suitable for high-power-density SiC power devices, which comprises: parallel SiC module substrates, jet impact heat dissipation bottom plates, jet impact spoiler plates, through holes, fluid outlets, sealing grooves, fluid inlets, threaded holes, water cooling plates, micro-channel structures, upper spoiler plates and lower spoiler plates; compared with a traditional jet structure, the jet impact structure can greatly reduce the complexity of the system, simplify the assembly and design of the system, and also can improve the power density and reliability of the system; in addition, compared with a traditional integrated Pin-Fin heat sink, the jet impact heat dissipation structure can reduce the junction thermal resistance of the system and improve the heat dissipation efficiency; compared with a traditional jet impact heat dissipation structure, the novel jet structure simplifies the complexity of the structure, makes the structure more compact and easy to process, and has lower thermal resistance than the traditional Pin-Fin heat dissipation structure, and is more suitable for the application requirements of high-power-density power electronic converters.

Description

Technical Field

[0001] This invention belongs to the field of heat dissipation technology, and particularly relates to a high-efficiency heat dissipation structure suitable for high power density SiC power devices. Background Technology

[0002] With the continuous development of power electronics technology and the increasing demands for energy efficiency and system compactness, the power density of power electronic converters is showing a rapid growth trend. In high-performance application scenarios such as new energy vehicles, power transmission and distribution, high-end manufacturing, and new energy power generation, traditional silicon-based power devices are gradually becoming unable to meet the high-frequency, high-voltage, and high-temperature operation requirements due to their limitations in thermal stability and switching performance.

[0003] Silicon carbide (SiC), a third-generation semiconductor material, has become a new generation of power electronic switching device material to replace silicon-based devices due to its high breakdown voltage, high thermal conductivity, wide bandgap, and high electron mobility. Power modules built using SiC MOSFETs or SiC SBDs have significant advantages in improving efficiency, reducing system size and weight, and driving the development of high power density power electronic systems.

[0004] However, the direct challenge brought about by high power density is thermal management. Although SiC devices can withstand higher temperatures, their continued reliable operation still requires an efficient heat dissipation structure. Especially with the increasing integration of devices, such as the fast charging requirements of electric vehicles that demand power modules to handle higher currents in smaller volumes, traditional air cooling or ordinary liquid cooling solutions are insufficient in heat dissipation efficiency and cannot meet the high heat flux density requirements of SiC devices. There is an urgent need to develop new heat dissipation technologies to match the increasing power density and ensure device performance and lifespan.

[0005] To address the challenges of high heat flux, jet impingement cooling technology has gradually become a research hotspot in recent years. Jet cooling achieves enhanced local heat transfer by directly impacting the surface of a device or a cold plate with a high-velocity liquid or gas jet. This technology can achieve a high heat transfer coefficient in a very small area (locally up to 5-10 times that of traditional heat dissipation), and has good temperature control and response speed.

[0006] Several jet cooling structures have been proposed to date, including:

[0007] Vertical single-point jet structure: Liquid is jetted vertically from the nozzle onto the heating surface.

[0008] Array jet structure: Cooling is achieved over a large area by forming an array of multiple nozzles.

[0009] Closed cavity jet cooling: jet cooling combined with flow channel design optimizes coolant circulation.

[0010] Although the above structure improves cooling efficiency to some extent, the following problems still exist:

[0011] These designs require complex nozzle structures and circulation systems, resulting in a large size that is not suitable for integration into compact power modules;

[0012] Issues such as high energy consumption of circulating pumps, nozzle clogging, and leakage risks limit the application of jet structures in applications with high reliability requirements;

[0013] The manufacturing and design of the nozzles and water cooling system are quite complex.

[0014] Therefore, developing an improved jet impingement heat dissipation structure that is compact, has lower thermal resistance, and is suitable for high heat flux density SiC devices has become an important technological breakthrough direction in the field of thermal management.

[0015] Based on the above analysis, the problems and shortcomings of the existing technology are as follows:

[0016] (1) Existing designs require the addition of complex nozzle structures and circulation systems, resulting in a large volume that is not suitable for integration with compact power modules;

[0017] (2) Problems such as energy consumption of circulating pumps, nozzle clogging, and leakage risk limit the application of jet structures in applications with high reliability requirements;

[0018] (3) The processing and design of the nozzle and water cooling system are relatively complex. Summary of the Invention

[0019] To address the problems existing in the prior art, the present invention provides an efficient heat dissipation structure suitable for high power density SiC power devices.

[0020] This invention is implemented as follows: a high-efficiency heat dissipation structure suitable for high power density SiC power devices includes:

[0021] Parallel SiC module substrate, jet impact heat dissipation base plate, jet impact baffle plate, through hole, fluid outlet, sealing groove, fluid inlet, threaded hole, water cooling plate, microchannel structure, upper baffle plate, lower baffle plate;

[0022] The parallel SiC module substrate is connected to the jet impact heat dissipation base plate by welding. The heat dissipation base plate can be made of common heat dissipation materials such as copper and nickel plated on the surface. At the same time, a microchannel structure is added below the jet impact heat dissipation base plate according to the position of the chip above.

[0023] Furthermore, the structure of the jet impact baffle plate mainly consists of an upper baffle plate and a lower baffle plate; the square groove area at the top corresponds to the microchannel part of the jet impact heat dissipation base plate.

[0024] Furthermore, the water-cooled plate includes a fluid inlet, a fluid outlet, and a sealing groove; after the cooling fluid enters the flow channel from the fluid inlet, it is disturbed by the jet impact baffle plate and then flows out from the fluid outlet; it is pressed and fastened to the jet impact heat dissipation base plate by bolts through through holes and threaded holes, and an O-ring is added between the two for sealing.

[0025] Based on the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solution to be protected by this invention are as follows:

[0026] First, this invention was proposed in this context, aiming to simplify the complexity of the system and improve its integration and reliability while maintaining the high efficiency of jet cooling.

[0027] Traditional jet cooling structures require complex nozzle structures and cooling circulation systems, resulting in a relatively large overall heat dissipation system volume, which is difficult to meet the high power density requirements of SiC systems. To address these issues, this technology makes the following improvements: It abandons the complex nozzle structure and adds staggered baffles between the heat sink base plate and the water-cooled base plate. This allows the horizontally flowing cooling fluid to be redirected upon encountering the baffles, impacting the heat sink base plate upwards and forming a jet-impact cooling method. Simultaneously, by adding a microchannel structure to the bottom of the heat sink base plate, the contact area is increased, further reducing junction thermal resistance.

[0028] Compared to traditional jet structures, this jet impact structure significantly reduces system complexity, simplifies assembly and design, and improves power density and reliability. Furthermore, compared to traditional integrated pin-fin heatsinks, it reduces junction thermal resistance and enhances heat dissipation efficiency.

[0029] Compared to traditional jet impingement heat dissipation structures, the novel jet structure of this invention simplifies the complexity of the structure, while making the structure more compact and easier to manufacture. Moreover, it has lower thermal resistance than the traditional Pin-Fin heat dissipation structure, making it better suited for the application requirements of high power density power electronic converters.

[0030] Secondly, the core issue with traditional jet impingement cooling lies in balancing efficient heat transfer with system complexity. Jet impingement structures are often quite complex, requiring multiple layers working together. Correspondingly, the manufacturing precision of the components is also crucial, such as the size, angle, and spacing of the nozzles. Furthermore, impurities in the working fluid can clog the nozzles, necessitating filtration systems or self-cleaning designs. The complex structure also makes achieving high power density difficult. Although its heat transfer effect is indeed significantly improved, considering factors such as cost and system reliability, this cooling method is rarely used in practical applications.

[0031] However, the technical solution of this invention proposes a new jet impact structure that has no nozzles and no multi-layer structure. At the same time, it is basically the same size as the widely used Pin-Fin heat sink. Without sacrificing the power density of the system, it simplifies the structure of the jet impact, reduces the complexity of the structure, and can maintain the high-efficiency heat dissipation performance of the jet impact.

[0032] Traditional techniques achieve jet impact by arranging nozzles or orifices beneath the chip, and related research has consistently focused on the structural development of these nozzles or orifices, leading to the assumption that jet impact is solely dependent on them. This invention, however, abandons the traditional jet structure and nozzle or orifice approach. Instead, it utilizes a baffle plate to achieve jet impact on the heatsink beneath the heat source. This expands the structural possibilities of jet impact, making it more practical and promoting the real-world application of jet impact cooling methods. Attached Figure Description

[0033] Figure 1 This is a diagram of an efficient heat dissipation structure suitable for high power density SiC power devices provided in an embodiment of the present invention.

[0034] Figure 2 This is a top view of the jet impact heat dissipation base plate of the high power density SiC device provided in the embodiment of the present invention.

[0035] Figure 3 This is a diagram of the jet impact turbulence structure provided in an embodiment of the present invention.

[0036] Figure 4 This is a water-cooled plate diagram of the jet impact heat dissipation structure provided in an embodiment of the present invention.

[0037] Figure 5 This is a schematic diagram of fluid flow in an efficient heat dissipation structure suitable for high power density SiC power devices, provided by an embodiment of the present invention.

[0038] In the figure: 1. Parallel SiC module substrate; 2. Jet impact heat dissipation base plate; 3. Jet impact baffle plate; 4. Through hole; 5. Fluid outlet; 6. Sealing groove; 7. Fluid inlet; 8. Threaded hole; 9. Water cooling plate; 10. Microchannel structure; 11. Upper baffle plate; 12. Lower baffle plate. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0040] In the connection between the parallel SiC module substrate and the copper jet impingement heat dissipation base plate, the module substrate is metallurgically bonded to the base plate through uniform welds, forming a thermal path with low interfacial thermal resistance. After nickel plating, a microchannel structure is precisely machined directly beneath the chip on the surface of the base plate.

[0041] The jet impact spoiler consists of two parts: an upper spoiler and a lower spoiler, which are assembled at the microchannel outlet end via threaded holes and through holes. The upper spoiler forms a jet manifold, precisely setting the nozzle-surface distance (H / D≈2–4) to control the jet impact angle. The lower spoiler guides secondary backflow after jet deceleration. This assembly relationship utilizes O-rings to form a hydrostatic seal within the sealing groove, preventing coolant leakage. Simultaneously, bolt preload ensures elasto-plastic contact between the metal parts, achieving stable interface compression under dynamic thermo-mechanical coupling.

[0042] Cooling fluid enters the manifold from the fluid inlet through the inlet chamber, and is then distributed through precision apertures to the upper baffle to form an equal-flow jet. The jet impacts the bottom surface of the SiC device at high speed at the microchannel outlet on the bottom plate, breaking the boundary layer and generating a high-shear layer. Subsequently, the fluid enters the collection channel through the guide holes of the lower baffle and finally converges and discharges to the fluid outlet. This flow path utilizes the fluid-structure interaction design principle, and through the geometric complementarity of the upper and lower baffles, the velocity and pressure fields are balanced between the impact zone and the return zone, avoiding local thermal blind spots.

[0043] Functionally, the synergistic effect of jet impact and microchannel cooling improves heat transfer efficiency under both transient and steady-state conditions: the high-speed jet in the impact region can induce the flow to transition to a turbulent state when Re is ~10000, significantly improving local Nu; downstream eddy separation and secondary mixing further expand the heat exchange area and reduce the thermal boundary layer thickness; the entire module achieves a thermo-mechanical coupling design through the coaxial mounting of the integrated water-cooled plate and the base plate, which not only ensures the interface stability during thermal cycling, but also extends the device life by reducing the thermal stress gradient.

[0044] like Figure 1 As shown, the parallel SiC module substrate 1 is mounted on the top layer of the heat dissipation assembly and is firmly bonded to the jet impact heat dissipation base plate 2 below by low-gap brazing, forming a metal heat conduction channel with almost no thermal resistance. The heat generated by the device diffuses laterally inside the substrate and is then rapidly conducted downwards along the nickel-plated copper base plate, achieving efficient "surface-to-surface" thermal coupling from the power junction to the jet impact zone.

[0045] The coolant enters through the fluid inlet 7 on the side of the water-cooled plate 9, first flowing into the closed cavity above the jet impinging on the baffle 3. The multi-hole nozzles on the baffle shaped the incoming flow into a high-speed jet, precisely aiming at the center of the microchannel structure 10. The jet impacts the channel inlet head-on and instantly destroys the thermal boundary layer; subsequently, guided by the upper and lower baffle ribs 11 and 12, it repeatedly deflects back and forth, inducing strong shearing and reattachment, significantly improving the local heat transfer coefficient.

[0046] The heated liquid converges at the microchannel outlet and is discharged through fluid outlet 5, forming a closed loop. The jet impact heat dissipation base plate and the water cooling plate are pressed together by bolts through through holes 4 and threaded holes 8. The O-ring is embedded in the sealing groove 6, providing a bidirectional static seal under the action of pre-tightening force to ensure zero leakage under high-pressure jet conditions. The detachable structure facilitates the cleaning and maintenance of the microchannel.

[0047] The triple reinforcement method of "high-conductivity copper base plate + jet impact + microchannel turbulence" enables the coolant to absorb maximum heat within the shortest path, significantly reducing the junction temperature gradient of SiC devices. Simultaneously, the mesh-like threaded locking structure ensures the long-term reliability of high-power-density modules under thermo-mechanical cycles. Compared to traditional flat-plate water cooling solutions, this structure can increase heat flux density carrying capacity by more than 20% at the same flow rate, providing a compact and efficient heat dissipation platform for megawatt-level power converters.

[0048] This invention provides an efficient heat dissipation structure suitable for high power density SiC power devices, the specific structure of which is as follows: Figure 1-5 As shown, its main features include: a parallel SiC module substrate 1, a jet impact heat dissipation base plate 2, a jet impact baffle plate 3, and a corresponding water-cooling plate 9.

[0049] The parallel SiC module substrate 1 and the jet impact heat dissipation base plate 2 are connected by welding. The heat dissipation base plate is made of common heat dissipation materials such as copper and nickel plated on the surface. At the same time, a microchannel structure 10 is added below the jet impact heat dissipation base plate 2 according to the position of the chip above, which can increase the heat dissipation area and further enhance the heat exchange effect.

[0050] The structure of the jet impact baffle 3 mainly consists of an upper baffle 11 and a lower baffle 12. Through their alternating arrangement, the fluid can change its flow direction when flowing through it, changing from parallel flow to jet flow. The square groove area at the top corresponds to the microchannel part of the jet impact heat dissipation base plate 2, and the two work together. Since it does not directly participate in heat transfer, the thermal conductivity of the material has little impact, and it can be made of lightweight metal alloys such as aluminum and titanium or polymers such as PEEK and ABS.

[0051] The water-cooled plate 9 includes a fluid inlet 7, a fluid outlet 5, and a sealing groove 6. After the cooling fluid enters the flow channel through the fluid inlet 7, it is disturbed by the jet impact baffle 3 and then flows out from the fluid outlet 5. It is fastened to the jet impact heat dissipation base plate 2 by bolts through the through hole 4 and the threaded hole 8, and an O-ring is added between the two for sealing.

[0052] Compared to traditional jet impingement heat dissipation structures, the novel jet structure of this invention simplifies the complexity of the structure, while making the structure more compact and easier to manufacture. Moreover, it has lower thermal resistance than the traditional Pin-Fin heat dissipation structure, making it better suited for the application requirements of high power density power electronic converters.

[0053] High-power-density SiC can also be used as an application example of jet impingement heat dissipation structure in water cooling for other high-power-density semiconductor devices. The structure, from top to bottom, consists of: SiC power electronic converter power module 1, jet impingement heat dissipation base plate 2, jet impingement baffle plate 3, and corresponding water cooling plate 9. The jet impingement heat dissipation base plate 2, jet impingement baffle plate 3, and corresponding water cooling plate 9 are all CNC machined, and the materials are copper, aluminum, and aluminum, respectively. O-ring gaskets are added between the jet impingement heat dissipation base plate 2 and the corresponding water cooling plate 9, and a pressure seal is achieved using bolts. Common cooling fluids such as ethylene glycol solution, water, and deionized water can be used. The fluid inlet 7 and fluid outlet 5 are connected to external pipes via quick-connect fittings and are connected to an external water cooler to provide fluid circulation and cooling.

[0054] Numerical simulation analysis shows that the proposed high-efficiency heat dissipation structure for high power density SiC power devices has better heat dissipation efficiency than the traditional Pin-Fin heat dissipation structure. Under the same chip operating conditions, the proposed solution can reduce junction thermal resistance by about 5% and fluid pressure drop by about 10%.

[0055] High power density: refers to the ability to provide a large amount of power output within a limited volume or space. In power electronic converters, high power density usually means smaller size and higher efficiency. SiC: SiC is a wide bandgap semiconductor material characterized by high temperature, high frequency, high voltage, and high power. Due to its superior thermal conductivity and high temperature resistance, SiC is often used in high power density applications. Jet impingement: a cooling method that enhances convective heat transfer by directly impacting the device or heat sink surface with a high-speed jet of liquid or gas, carrying away a large amount of heat. Heat dissipation structure: refers to a complete set of thermal management design structures to efficiently conduct, diffuse, and ultimately release the heat generated during device operation into the environment.

[0056] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-efficiency heat dissipation structure suitable for high power density SiC power devices, characterized in that, The system includes a parallel SiC module substrate, a jet impact heat dissipation base plate, a jet impact baffle plate, microchannel structures arranged equidistantly along the surface of the base plate below the jet impact heat dissipation base plate, a water-cooled plate, through holes and threaded holes connecting the jet impact heat dissipation base plate and the water-cooled plate, fluid inlets, fluid outlets, and sealing grooves on both sides of the water-cooled plate. The parallel SiC module substrate is welded to the jet impact heat dissipation base plate, which is made of copper and nickel-plated. The water-cooled plate is bolted through the through holes and threaded holes and is pressed tightly against the jet impact heat dissipation base plate. An O-ring is embedded in the sealing groove. The jet impact spoiler consists of an upper spoiler and a lower spoiler, with a jet channel formed between the upper and lower spoilers; The top surface of the upper spoiler has a square groove in the central area, and the square groove is aligned with the microchannel structure in the projection direction.

2. The heat dissipation structure according to claim 1, characterized in that, The fluid inlet and fluid outlet are respectively located in the grooves on both sides of the water-cooled plate, and the sealing groove forms a closed loop along the outer periphery of the fluid inlet and fluid outlet.

3. The heat dissipation structure according to claim 1, characterized in that, The diameter of the through hole is D1, the diameter of the threaded hole is D2, and the axial direction of the through hole and the threaded hole is parallel to the parallel SiC module substrate.

4. The heat dissipation structure according to claim 1, characterized in that, The welding connection between the parallel SiC module substrate and the jet impact heat dissipation base plate is gold active soldering or brazing.

5. The heat dissipation structure according to claim 1, characterized in that, The parallel SiC module substrate has a sealing groove on the joint surface with the jet impact heat dissipation base plate.

6. A heat dissipation method for a high-power-density SiC power device applied to the efficient heat dissipation structure of any one of claims 1-5, suitable for high-power-density SiC power devices, characterized in that the steps include... include: a. Weld the parallel SiC module substrate onto the jet impact heat dissipation base plate; b. Use bolts to press and fix the water-cooled plate under the jet impact heat dissipation base plate through the through holes and threaded holes, and place an O-ring seal in the sealing groove; c. The coolant enters from the fluid inlet, is sprayed by the jet impact baffle, and then vertically impacts the microchannel structure before flowing through the microchannel to the fluid outlet for discharge; d. Control the junction temperature of SiC power devices within a set range by adjusting the coolant flow rate and inlet temperature.

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