Immersed phase-change heat exchange structure of power electronic device

Abstract

An immersed phase-change heat exchange structure of a power electronic device comprises a heat dissipation substrate used for being in contact with a heat source of the power electronic device; the heat dissipation structure main body is vertically immersed in the phase change working medium and comprises a plate-shaped structure and fin-shaped structures distributed on the plate-shaped structure at intervals, the fin-shaped structures gradually incline and deviate from the plate-shaped structure in the height direction, and the tail parts of the fin-shaped structures are provided with concave arc-shaped structures; the plate-shaped structure is provided with a trapezoidal micro-channel in an area which is not covered by the fin-shaped structure. According to the immersed phase change heat exchange structure, the maximum heat flux density of phase change cooling can be remarkably improved, the thermal stress of the structure can be reduced, thermal runaway of the power electronic device caused by too high temperature can be effectively prevented, and support is provided for safe operation of the power electronic device and a power grid.

Description

Technical Field

[0001] This invention relates to the field of heat exchange technology, and in particular to an immersion phase change heat exchange structure for power electronic devices. Background Art

[0002] In recent years, high-power power electronic devices, such as insulated-gate bipolar transistors (IGBTs), have been continuously developing, showing a trend of increasingly higher power levels and smaller device sizes. The heat generated during their operation increases dramatically, and heat dissipation performance has become a key bottleneck restricting the reliability, lifespan, and energy efficiency of these devices. Traditional heat dissipation technologies (such as air cooling and liquid cooling) have gradually revealed shortcomings such as insufficient heat transfer efficiency and poor temperature uniformity in high heat flux density scenarios. Immersion phase change cooling technology, due to its advantages of high heat capacity, low thermal resistance, and utilization of latent heat of phase change, has become a research hotspot in the field of high-power heat dissipation. This technology directly immerses the heat-generating device in an insulating working fluid, utilizing the boiling and vaporization of the working fluid to absorb a large amount of heat, followed by continuous heat dissipation through a condensation cycle. However, existing immersion phase change cooling structures still suffer from problems in practical applications, such as low bubble detachment efficiency, a single heat conduction path, and insufficient dynamic adaptability.

[0003] Currently, the main methods to enhance immersion phase change cooling processes include optimizing the microstructure of the heat sink surface (such as micropillar arrays and porous coatings). However, changes in the microsurface structure can lead to inconsistent results; different researchers designing the same microsurface modification can produce drastically different heat dissipation characteristics. Another major approach to enhancing heat dissipation is to study the corresponding phase change materials. Currently, the main phase change materials used in immersion phase change cooling are fluorocarbon compounds, but these are too expensive and have environmental impacts. Furthermore, existing technologies lack sufficient research on the synergistic optimization of the phase change working fluid and the heat dissipation structure, failing to fully realize the heat transfer potential of immersion phase change cooling.

[0004] It should be noted that the information disclosed in the background section above is only for understanding the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The main objective of this invention is to overcome the deficiencies in the prior art and provide an immersion phase change heat transfer structure for power electronic devices, thereby improving the heat dissipation reliability and efficiency of high power density power electronic devices and preventing thermal runaway.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: An immersion phase change heat transfer structure for power electronic devices, comprising: A heat dissipation substrate, used to contact the heat source of power electronic devices; The main body of the heat dissipation structure is vertically immersed in the phase change working fluid, including a plate-like structure and fin-like structures spaced apart thereon. The fin-like structures gradually tilt away from the plate-like structure along the height direction. The tail of the fin-like structure is provided with a concave arc-shaped structure. The plate-like structure is provided with trapezoidal microchannels in the area not covered by the fin-like structure.

[0007] Furthermore, the tilt angle of the fin-like structure is 10°-20°.

[0008] Furthermore, the central angle corresponding to the arc shape at the tail of the fin-like structure is 30°-45°.

[0009] Furthermore, the surface of the fin-like structure is distributed with circular holes, which are obtained by Boolean subtraction of cylinders with a radius of 0.1-0.5 mm in the direction perpendicular to the ground and the axis of the fin-like structure, and the spacing between the holes is 1-2 mm.

[0010] Furthermore, the trapezoidal microchannel forms a channel opening at the upper base of the trapezoid and a channel bottom at the lower base of the trapezoid.

[0011] Furthermore, the trapezoidal microchannel has an inclination angle of 20°-30°, an upper base length of 0.05-0.15mm, and a lower base length of 0.25-0.35mm.

[0012] Furthermore, the width of the fin structure is set to 2-6 mm according to the power of the heat source.

[0013] Furthermore, the material of the main body of the heat dissipation structure is selected from copper, copper alloy, aluminum or aluminum alloy.

[0014] The present invention has the following beneficial effects: This invention, through an innovative immersion phase change heat transfer structure design, combined with the tilt angle of the finned structure, the arc shape of the tail, and the surface perforation layout, effectively optimizes bubble detachment efficiency and liquid working fluid replenishment capability. The tilted finned structure blocks the continuous growth of the gas film and accelerates bubble detachment using the tilt angle; the arc-shaped tail design increases the nucleation boiling points and promotes liquid reflux through capillary action; and the circular perforations on the surface inhibit gas film formation and guide the discharge of microbubbles, thus avoiding localized dry burning. Simultaneously, the trapezoidal microchannels on the plate-like structure enhance the rapid flow of the liquid working fluid to high heat flux density regions through capillary effect, significantly improving the latent heat utilization efficiency of the phase change. Compared with traditional heat dissipation structures, this design achieves an efficiency improvement of over 5% with the same heat dissipation area under high power density conditions, breaking through the heat dissipation bottleneck of high-power power electronic devices and significantly improving the heat dissipation performance and operational reliability of high-power density power electronic devices under immersion phase change cooling conditions.

[0015] The irregularly shaped immersion phase change heat dissipation structure designed in this invention further solves the problems of single heat conduction path and insufficient dynamic adaptability in traditional immersion cooling by synergistically optimizing the dynamic interaction between the heat dissipation structure and the phase change working fluid. The width, tilt angle of the fin structure, and the geometric parameters of the trapezoidal microchannels are all precisely designed for the heat source power and fluid characteristics, which not only reduces the thermal stress of the structure but also improves the maximum heat flux density carrying capacity. This multi-scale structural innovation and the synergistic effect of the working fluid flow ensure the temperature uniformity and stability of the heat dissipation process, effectively prevent thermal runaway of the device, and provide technical guarantee for the reliable operation of high-power power electronic equipment.

[0016] Other beneficial effects of the embodiments of the present invention will be further described below. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the immersion phase change heat transfer structure of a power electronic device according to an embodiment of the present invention.

[0018] Figure 2 This is a front view of the fin structure distribution according to an embodiment of the present invention.

[0019] Figure 3 This is an enlarged schematic diagram of the arc-shaped structure at the tail end of the fin-like structure and the trapezoidal microchannel in an embodiment of the present invention.

[0020] Figure 4 This is a schematic diagram of the pore distribution of the fin-like structure according to an embodiment of the present invention.

[0021] Figure 5(a) shows the simulation results of a plate-fin radiator structure used in traditional air cooling under high heat flux density.

[0022] Figure 5(b) shows the simulation results of the embodiment of the present invention under high heat flux density.

[0023] Reference numerals in the attached figures: 1 is the heat dissipation substrate, 2 is the heat sink fin, 3 is the fin-like structure on the heat sink fin, 31 is the circular hole on the fin-like structure, 32 is the arc-shaped structure at the tail end of the fin-like structure, 4 is the trapezoidal microchannel on the heat sink fin, 41 is the upper bottom of the trapezoidal microchannel, and 42 is the lower bottom of the trapezoidal microchannel. Detailed Implementation

[0024] The embodiments of the present invention will be described in detail below. It should be emphasized that the following description is merely exemplary and not intended to limit the scope and application of the present invention.

[0025] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to that other component. Furthermore, a connection can be used for fixing, coupling, or communication.

[0026] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0027] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0028] Current phase change cooling technologies primarily utilize air cooling and liquid cooling structures, failing to fully leverage the advantages of phase change cooling. This results in insufficient heat dissipation efficiency and can even lead to excessively high localized dryness, causing device temperatures to exceed limits. This invention proposes a novel immersion-type phase change cooling structure that avoids localized dry burning, combining principles of bubble dynamics and capillary action.

[0029] See Figures 1 to 4 This invention provides an immersion phase change heat dissipation structure for power electronic devices, serving as a heat sink for the devices. The structure includes: a heat dissipation substrate 1 for contacting the heat source of the power electronic device; and a main body of the heat dissipation structure, vertically immersed in a phase change working fluid, comprising a plate-like structure serving as heat sink fins 2 and fin-like structures 3 spaced apart thereon. The fin-like structures 3 gradually tilt away from the plate-like structure along their height direction, and the tail of each fin-like structure 3 has a concave arc-shaped structure 32. Trapezoidal microchannels 4 are provided in the areas of the plate-like structure not covered by the fin-like structures 3. The arc-shaped tail of the fin-like structures 3 promotes the replenishment of the liquid working fluid through capillary action, and its tilt angle and distribution spacing accelerate bubble detachment. The trapezoidal microchannels 4 enhance the flow of the liquid working fluid to the heat source area through capillary action, rapidly replenishing the root of the plate-like structure where the phase change is most intense. This strengthens the gas-liquid phase change cooling process under immersion, avoids localized dry burning, and improves heat dissipation efficiency.

[0030] In a preferred embodiment, the tilt angle of the fin structure 3 is 10°-20°.

[0031] In a preferred embodiment, the central angle corresponding to the arc-shaped structure 32 at the tail of the fin structure 3 is 30°-45°.

[0032] See Figure 1 and Figure 4 In a preferred embodiment, the surface of the fin-like structure 3 is distributed with circular holes 31. Each circular hole 31 is obtained by Boolean subtraction of a cylinder with a radius of 0.1-0.5 mm perpendicular to the ground axis of the fin-like structure 3. The spacing between the holes is 1-2 mm. The circular holes 31 are used to suppress the formation of an air film and guide the discharge of microbubbles. The circular holes can be through holes, with a depth consistent with the thickness of the fin-like structure, and the cylinder axis perpendicular to the horizontal plane, guiding the bubbles out.

[0033] See Figure 3 In a preferred embodiment, the trapezoidal microchannel forms an opening at the upper base of the trapezoid and a bottom at the lower base. In a more preferred embodiment, the inclination angle of the trapezoidal waist of the trapezoidal microchannel 4 is 20°-30°, the length of the upper base 41 is 0.05-0.15mm, and the length of the lower base 42 is 0.25-0.35mm.

[0034] In some embodiments, the width of the fin structure 3 is set to 2-6 mm according to the heat source power.

[0035] In some embodiments, the material of the heat dissipation structure body is selected from copper, copper alloy, aluminum, or aluminum alloy.

[0036] In the immersion phase change cooling structure for power electronic devices proposed in this invention, the arc-shaped tail of the fin structure works synergistically with the trapezoidal microchannels. Through the increase in nucleation boiling points and rapid liquid phase replenishment, the heat dissipation efficiency is improved by more than 5% compared to traditional plate-fin structures. This immersion phase change cooling structure can significantly increase the maximum heat flux density of phase change cooling and reduce structural thermal stress, effectively preventing thermal runaway of power electronic devices caused by excessive temperature, and providing support for the safe operation of power electronic devices and the power grid.

[0037] The following describes specific embodiments of the present invention.

[0038] Structural diagram as follows Figure 1As shown, the heat sink mainly consists of two parts: a heat dissipation base plate and a heat dissipation structure body. The heat sink is vertically immersed in a large volume of phase change material, utilizing the natural buoyancy of air bubbles to achieve gas-liquid separation, thus negligible influence of the heat source and the heat sink on the temperature of the liquid at a distance. The heat dissipation structure body includes a plate-like structure and fin-shaped cross-sections spaced apart on it, with trapezoidal microchannels on the plate-like structure. The following description assumes the heat sink is placed vertically with the arc-shaped openings of the fin-shaped structures facing away from the ground. The phase change material can be a high-insulation, low-boiling-point fluorinated liquid (such as FC-72, Novec 7100) or deionized water (for waterproofing requirements of adapter components), etc.

[0039] Figure 2 This is a front view of the fin structure distribution according to an embodiment of the present invention. Figure 3 This is an enlarged schematic diagram of the arc-shaped structure at the tail end of the fin-like structure and the trapezoidal microchannels in an embodiment of the present invention. All fin-like structures in the heat sink can be identical, with their height gradually increasing with ground clearance. The tail end of the fin-like structure gradually deviates with increasing ground clearance, with an inclination angle between 10° and 20°. The width is set within the range of 2-6mm depending on the power of the heat source. An arc-shaped structure is present at the tail end of the fin-like structure, with a corresponding central angle between 30° and 45°. Boolean subtraction is performed on cylinders with a radius of 0.1-0.5mm perpendicular to the ground axis of the fin-like structure to obtain holes with a spacing of 1-2mm. Figure 4 This is a schematic diagram of the pore distribution of the fin-like structure according to an embodiment of the present invention.

[0040] Trapezoidal microchannels are provided in the areas of the main plate-like structure not covered by the fin-like structure, with corresponding tilt angles between 20° and 30°. The upper base of the trapezoid is between 0.05 and 0.15 mm in length, and the lower base is between 0.25 and 0.35 mm in length. A certain gap is left between the microchannels.

[0041] The main structure and finned structure of the radiator are made of copper, copper alloys, aluminum, aluminum alloys, etc.

[0042] During heat dissipation, the protrusions of the finned structure of this invention prevent the bubble film generated by the phase change material after absorbing heat under high heat density from growing to a certain length, making it difficult for it to aggregate into a continuous gas film. Furthermore, a certain tilt angle promotes rapid bubble detachment. In addition, the arc-shaped design at the tail end increases the number of nucleation boiling points and allows capillary action to promote the rapid entry of surrounding liquid into the arc-shaped region, causing the bubbles to detach. Under high heat flux density, when the bubbles are relatively continuous and mostly foamy, forming a gas film on a certain slope of the finned structure, the circular holes in the middle section of the finned structure allow some tiny bubbles to escape through the holes, thereby inhibiting the formation of the gas film and preventing the formation of dry-burning on the wall. In the trapezoidal microchannels in the area not covered by the finned structure, capillary action absorbs liquid from around the radiator and quickly replenishes it to the root of the plate-shaped structure where the phase change is most intense, improving heat dissipation performance. Figure 5(a) shows the simulation results of a plate-fin radiator structure used in traditional air cooling under high heat flux density, and Figure 5(b) shows the simulation results of an embodiment of this invention under high heat flux density. Simulation experiments have verified that, compared with traditional plate-fin heat sinks used in air cooling, the heat dissipation efficiency increases significantly with increasing power density for the same heat dissipation area. Furthermore, at high power densities, this invention can achieve a heat dissipation efficiency improvement of 5% or more. The heat transfer coefficient and maximum heat flux density carrying capacity are superior to traditional plate-fin structures. Compared with existing heat dissipation structures, the structure of this invention achieves rapid bubble detachment and rapid liquid phase replenishment through innovative design, improving the heat dissipation efficiency of immersion phase change cooling and overcoming the heat dissipation bottleneck of high-power power electronic devices.

[0043] The above description provides a further detailed explanation of the present invention in conjunction with specific / preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the concept of the present invention, and all such substitutions or modifications should be considered within the scope of protection of the present invention. In the description of this specification, the reference to terms such as "an embodiment," "some embodiments," "preferred embodiment," "example," "specific example," or "some examples," etc., indicates that the specific features, structures, materials, or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. An immersion phase change heat transfer structure for power electronic devices, characterized in that, include: A heat dissipation substrate, used to contact the heat source of power electronic devices; The main body of the heat dissipation structure is vertically immersed in the phase change working fluid, including a plate-like structure and fin-like structures spaced apart thereon. The fin-like structures gradually tilt away from the plate-like structure along the height direction. The tail of the fin-like structure is provided with a concave arc-shaped structure. The plate-like structure is provided with trapezoidal microchannels in the area not covered by the fin-like structure.

2. The immersion phase change heat transfer structure according to claim 1, characterized in that, The tilt angle of the fin-like structure is 10°-20°.

3. The immersion phase change heat transfer structure according to claim 1, characterized in that, The central angle corresponding to the arc shape at the tail of the fin-like structure is 30°-45°.

4. The immersion phase change heat transfer structure according to claim 1, characterized in that, The surface of the fin-like structure is distributed with circular holes. The circular holes are obtained by Boolean subtraction of cylinders with a radius of 0.1-0.5 mm in the direction perpendicular to the ground and the axis of the fin-like structure. The spacing between the holes is 1-2 mm.

5. The immersion phase change heat transfer structure according to claim 1, characterized in that, The trapezoidal microchannel forms a channel opening at the upper base of the trapezoid and a channel bottom at the lower base of the trapezoid.

6. The immersion phase change heat transfer structure according to claim 5, characterized in that, The trapezoidal microchannel has an inclination angle of 20°-30°, an upper base length of 0.05-0.15mm, and a lower base length of 0.25-0.35mm.

7. The immersion phase change heat transfer structure according to claim 1, characterized in that, The width of the fin structure is set to 2-6 mm according to the power of the heat source.

8. The immersion phase change heat transfer structure according to any one of claims 1 to 7, characterized in that, The material of the main body of the heat dissipation structure is selected from copper, copper alloy, aluminum or aluminum alloy.

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