3DVC radiator with independent working medium backflow passage

Abstract

The invention relates to the technical field of radiators, in particular to a 3DVC radiator with an independent working medium backflow channel. The 3DVC radiator comprises a hot plate and at least one cooling piece with a condensation cavity, a connector and a flow guide piece are arranged in the hot plate, the cooling piece is communicated with a cavity of the hot plate through the connector, the cavity and the condensation cavity form a vacuum cavity, the connector is provided with a flow guide groove, the flow guide groove is connected with the opening end of the condensation cavity, and the flow guide piece is connected with the flow guide groove. A liquid storage capillary structure is arranged on the inner bottom face of the hot plate, and the drainage groove and the liquid storage capillary structure form a working medium circulation channel through a flow guide piece. The scheme provided by the invention has the advantages of optimizing the flow path of the working medium, reducing the accumulation of the working medium, avoiding deformation and structural damage caused by icing expansion, and improving the reliability and the temperature cycle test capability.

Description

A 3DVC heatsink with an independent working fluid return path Technical Field

[0001] This application relates to the field of heat sink technology, and more particularly to a 3DVC heat sink with an independent working fluid return path. Background Technology

[0002] Currently, the liquid return path of 3DVC heat pipes mainly relies on the capillary structure of the cover or base plate. To meet the thermal conductivity requirements of high-power, high-heat-flux-density chips, the water saturation of the working fluid inside the 3DVC needs to exceed 90%, or even reach 110%. In high and low temperature thermal shock and temperature cycling reliability tests, a large amount of working fluid accumulates inside the capillary structure of the heat pipe opening, the base plate of the vapor chamber, and the cover plate. Under low temperature conditions, the working fluid freezes and expands in volume. Repeated thermal shocks can cause the base plate, cover plate, or bottom of the heat pipe to bulge and deform, thereby damaging the internal capillary structure, drastically reducing the thermal conductivity, and ultimately causing the 3DVC to fail the reliability test. Summary of the Invention

[0003] To overcome the problems existing in related technologies, this application provides a 3DVC heatsink with an independent working fluid return path. By building an independent working fluid return channel inside the evaporation chamber of the heatsink, the traditional liquid return path that relies on the capillary structure of the base plate or cover plate is replaced. This fundamentally avoids the structural bulging problem caused by thermal shock under high water content, and significantly improves the high and low temperature cycle reliability and service life of the 3DVC heatsink with an independent working fluid return path.

[0004] This application provides a 3DVC heat sink with an independent working fluid return path, including a hot plate and at least one cooling component with a condensation cavity. The hot plate has a connector and a flow guide inside. The cooling component is connected to the cavity of the hot plate through the connector, and the cavity and the condensation cavity form a vacuum cavity. The connector has a flow channel, which is connected to the opening end of the condensation cavity. The inner bottom surface of the hot plate is provided with a liquid storage capillary structure. The flow channel and the liquid storage capillary structure form a working fluid circulation path through the flow guide.

[0005] In some embodiments, the hot plate includes a cover plate and a bottom plate, the cover plate sealingly covering the bottom plate and the cover plate and the bottom plate enclosing the cavity, and the bottom plate is provided with a plurality of support members that abut against the cover plate.

[0006] In some embodiments, the liquid storage capillary structure is a first capillary structure layer disposed on the inner surface of the base plate; the side of the cover plate facing the base plate is a smooth surface, or is provided with a second capillary structure layer.

[0007] In some embodiments, the surface of the base plate facing the cover plate is flat or has a groove.

[0008] In some embodiments, the cooling element includes either a circular heat pipe or a square heat pipe. If the cooling element is a circular heat pipe, it is brazed to the cover plate. If the cooling element is a square heat pipe, it is integrally formed with the base plate or brazed to it.

[0009] In some embodiments, the drainage channel is provided with an inclined drainage surface facing the drainage element.

[0010] In some embodiments, the drainage channel is provided with a third capillary structure layer, the connection between the connector and the cooling component is provided with a capillary core, and the inner wall of the condensation chamber of the cooling component is provided with a fourth capillary structure layer; the third capillary structure layer, the capillary core and the fourth capillary structure layer are in contact with each other to form a continuous capillary passage.

[0011] In some embodiments, the flow guide is provided with a fifth capillary connection structure, which is connected to the third capillary structure layer and the liquid storage capillary structure respectively; the third capillary structure layer, the fifth capillary connection structure, and the capillary core are formed by any one of sintered copper powder, copper mesh, and copper braided tape.

[0012] In some embodiments, the connector includes a sleeve, a disc, and a plurality of support columns. The disc is sleeved around the outer periphery of the sleeve, and the drain groove is formed around the surface of the disc around the sleeve. The support columns are located at the bottom of the disc.

[0013] In some embodiments, the flow guide includes a flow guide tube and a plurality of support blocks; the support blocks are spaced apart on the inner bottom surface of the hot plate, and the flow guide tube is mounted above the support blocks; the flow guide tube has an inclined flow channel facing the liquid storage capillary structure.

[0014] As can be seen from the above, the 3DVC radiator with an independent working fluid return path provided in this application can guide and converge the working fluid in the condensation chamber of the cooling component through the joints and flow guides set inside the evaporation chamber of the hot plate. This achieves an optimized design of the working fluid flow path and has significant technical effects such as optimizing working fluid circulation, reducing working fluid residue, avoiding structural failure caused by low-temperature freezing expansion, improving product reliability and temperature cycle test pass rate. Attached Figure Description

[0015] The above and other objects, features and advantages of this application will become more apparent from the more detailed description of exemplary embodiments thereof in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments thereof.

[0016] Figure 1 is a structural schematic diagram of a 3DVC heatsink with an independent working fluid return path shown in Embodiment 1 of this application; Figure 2 is an exploded structural schematic diagram of a 3DVC heatsink with an independent working fluid return path shown in Embodiment 1 of this application; Figure 3 is an exploded structural schematic diagram of another 3DVC heatsink with an independent working fluid return path shown in Embodiment 1 of this application; Figure 4 is a structural schematic diagram of a flow guide shown in Embodiment 1 of this application; Figure 5 is another structural schematic diagram of a flow guide shown in Embodiment 1 of this application; Figure 6 is a detailed schematic diagram of the fourth capillary structure layer shown in Embodiment 2 of this application; Figure 7 is a detailed schematic diagram of the capillary structure of the connector, flow guide, and liquid storage capillary structure shown in Embodiment 3 of this application; Figure 8 is a structural schematic diagram of a 3DVC heatsink with an independent working fluid return path shown in Embodiment 4 of this application; Figure 9 is a structural schematic diagram of a 3DVC heatsink with an independent working fluid return path shown in Embodiment 4 of this application after removing the cover plate; Figure 10 is an assembly schematic diagram of the cooling component and connector shown in Embodiment 4 of this application.

[0017] Reference numerals: 1. Hot plate; 10. Connector; 100. Drainage channel; 101. Sleeve; 102. Disc; 103. Support column; 11. Flow guide; 12. Liquid storage capillary structure; 13. Cover plate; 14. Bottom plate; 15. Support; 16. Third capillary structure layer; 17. Capillary core; 18. Fifth capillary connection structure; 2. Cooling component; 20. Fourth capillary structure layer. Detailed Implementation

[0018] Preferred embodiments of the present application will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the present application are shown in the drawings, it should be understood that the present application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0019] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0020] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0021] In high heat flux density applications such as AI training servers, high-power GPU chips, and automotive-grade IGBT modules, the heat flux density of chips has exceeded 100W / cm², making it difficult for traditional vapor chamber heat sinks to meet the heat dissipation requirements. 3DVC heat sinks with independent working fluid return paths achieve three-dimensional heat conduction by integrating heat pipes and vapor chambers. To meet the high heat flux density heat conduction requirements, a mature approach in this field is to increase the water saturation of the internal working fluid to over 90%, or even 110%, to enhance phase change cycle efficiency. However, in actual high and low temperature cycle reliability tests and long-term operation, 3DVC heat sinks with high water content and independent working fluid return paths exhibit problems such as vapor chamber bulging and deformation, and capillary structure failure.

[0022] Through in-depth research and failure analysis, the inventors discovered that when the heat pipe is working, the working fluid vaporized in the 3DVC radiator with an independent working fluid return path liquefies in the condensation chamber of the heat pipe. Traditional solutions rely on the capillary structure of the base plate / cover plate to return to the evaporation chamber of the vapor chamber. However, under high heat flux density, the amount of condensate is large. In a short time, a large amount of liquid working fluid will accumulate in the area of ​​the heat pipe opening towards the evaporation chamber. This area is also part of the heat source's working surface. Therefore, the accumulated liquid working fluid will be rapidly heated and vaporized, causing a sudden increase in local pressure and forming a vapor explosion effect. The instantaneous pressure peak can reach several times the normal operating pressure. Meanwhile, in low-temperature environments, liquid working fluid that is not returned to the storage area in time will freeze inside the opening of the condensation chamber, the capillary structure of the cover plate, and the capillary structure of the bottom plate. The volume expansion rate is about 9%. During repeated hot and cold cycles, the expansion and contraction of ice will create alternating stress concentration at the weld between the cover plate and the bottom plate, and at the weld between the heat pipe and the cover plate. This will eventually lead to irreversible bulging deformation of the bottom plate, cover plate, or heat pipe, destroying the continuity of the internal capillary structure, resulting in a significant decrease in heat dissipation performance, or even direct failure.

[0023] To address the dual failure issues of vapor explosion and icing expansion caused by working fluid accumulation in 3DVC radiators with high water content and independent working fluid return paths, this application proposes a 3DVC radiator with an independent return system and an independent working fluid return path. By constructing a dedicated working fluid return channel composed of a connector 10 and a guide 11 within the evaporation chamber of the hot plate 1, the traditional reliance on the capillary structure of the base plate 14 or cover plate 13 for liquid return is replaced. This fundamentally cuts off the chain reaction of local accumulation and high-temperature vaporization of the working fluid at the opening of the condensation chamber. At the same time, it avoids the capillary structure of the base plate 14 and cover plate 13 bearing the stress of thermal cycling. This allows the 3DVC radiator with an independent working fluid return path to meet the high heat flux density heat dissipation requirements of working fluid with a water content of over 90%, while improving the high and low temperature cycle reliability and service life of the radiator.

[0024] The technical solutions of the embodiments of this application are described in detail below with reference to the accompanying drawings.

[0025] Figure 1 is a schematic diagram of the structure of a 3DVC heat sink with an independent working fluid return path shown in Embodiment 1 of this application.

[0026] Please refer to Figures 1 to 3. Embodiment 1 of this application proposes a gravity-flow type 3DVC radiator with an independent working fluid return path, suitable for scenarios where the hot plate 1 is placed horizontally when in contact with the heat source, achieving natural return of the condensing working fluid by gravity. This 3DVC radiator with an independent working fluid return path includes a hot plate 1 and at least one cooling component 2 with a condensation chamber. The hot plate 1 has a connector 10 and a flow guide 11 inside. The cooling component 2 connects to the chamber of the hot plate 1 through the connector 10, and the chamber and the condensation chamber form a vacuum chamber. The connector 10 has a flow channel 100 connected to the opening end of the condensation chamber. The inner bottom surface of the hot plate 1 is equipped with a liquid storage capillary structure 12, and the flow channel 100 forms a working fluid circulation path with the liquid storage capillary structure 12 through the flow guide 11.

[0027] Specifically, when the hot plate 1 is horizontally attached to the surface of the heat source, the liquid working fluid stored in the liquid storage capillary structure 12 is heated and vaporized. The vapor enters the condensation chamber of the cooling component 2 through the connector 10, and condenses into liquid after sufficient heat exchange with the air or liquid through the external heat dissipation fins in the cooling component 2. It then flows back to the opening end of the condensation chamber by gravity. The condensed working fluid flows into the guide component 11 through the guide groove 100 of the connector 10, and then flows back to the liquid storage capillary structure 12 through the guide component 11, thereby completing the closed loop of evaporation, transportation, condensation and return, and continuously removing heat from the heat source.

[0028] The hot plate 1 is a flat, sealed structure, with an internal chamber formed by a cover plate 13 and a base plate 14 sealed together by diffusion welding or copper solder paste brazing. The cover plate 13 forms the top surface of the hot plate 1, and its inner surface facing the base plate 14 is smooth. The cover plate 13 has outwardly flanged insertion holes corresponding to the number of cooling components 2, which allow for initial positioning and fixation of the cooling components 2 after insertion. The surface of the base plate 14 facing the cover plate 13 is provided with a liquid storage capillary structure 12, which can be formed by sintering copper powder, copper mesh, or copper braided strip. In specific implementation, as shown in Figure 2, the liquid storage capillary structure 12 can be locally adapted. In this case, the liquid storage capillary structure 12 is only set in the area of ​​the base plate 14 corresponding to the heat source action surface, forming an evaporation zone that is precisely matched with the heat source. Under this layout, the heat from the heat source can be directly transferred to the liquid working fluid through the liquid storage capillary structure 12, reducing thermal resistance. This setting method is suitable for scenarios where the heat source position is fixed and the heat flux density is concentrated. Furthermore, the liquid storage capillary structure 12 can also be arranged in a full-coverage layout. In this case, the liquid storage capillary structure 12 is laid out over the entire inner surface of the base plate 14, forming a continuous capillary network. This arrangement is suitable for scenarios where the heat source has a wide operating surface or the heat source location is not fixed, ensuring that the liquid working fluid is evenly distributed within the base plate 14 and avoiding localized thermal drying. In both of the above implementation methods, the bottom surface of the base plate 14 is a flat surface, which has good structural stability and can withstand higher thermal cycle stress, making it suitable for high-reliability special scenarios. When assembled to a heat source, the flat surface structure can be attached to the heat source using thermally conductive silicone grease or a phase change pad. As shown in Figure 3, the liquid storage capillary structure 12 can also be arranged in a groove-integrated layout. In this case, a groove adapted to the heat source operating surface is opened on the surface of the base plate 14 facing the cover plate 13, and the liquid storage capillary structure 12 is integrated inside the groove. The bottom of the groove of the liquid storage capillary structure 12 is lower than the reference mounting bottom surface of the base plate 14 (i.e., protruding towards the heat source side). This design utilizes the depth of the groove to increase the working fluid storage capacity while avoiding interference between the liquid storage structure and other components. It is suitable for scenarios with high working fluid storage capacity requirements, saves raw materials, and is suitable for mass production. When assembled to a heat source, the protruding structure of the groove can directly adhere to the heat source or be paired with a high thermal conductivity pad (graphite sheet, thermally conductive silicone) matching the thickness of the protrusion. To further enhance the working fluid collection efficiency, when the liquid storage capillary structure 12 adopts a groove-integrated or locally adapted layout, the surface of the base plate 14 facing the cover plate 13 can be designed as a funnel-shaped inclined surface, with the liquid storage capillary structure 12 located at the lowest point of the funnel. With the help of gravity, the liquid working fluid on the inner surface of the base plate 14 can automatically flow to the liquid storage capillary structure 12, ensuring sufficient working fluid supply to the evaporation zone and improving heat dissipation stability. At least one independent liquid storage capillary structure 12 can be set according to the number of heat sources, with each structure corresponding to a heat source area, adapting to scenarios with multiple heat sources and dispersed heat dissipation. In addition, several support members 15 are evenly distributed on the base plate 14, which abut against the inner surface of the cover plate 13 to resist external atmospheric pressure in a vacuum environment, maintain the structural strength of the hot plate 1, and prevent the chamber from being deformed by pressure.

[0029] As shown in Figure 4, the cooling component 2 provided in this embodiment 1 is a circular heat pipe structure made of metal. The material can be copper with excellent thermal conductivity or lightweight aluminum. One end of the circular heat pipe is an open end, and the other end is a closed end. Its internal condensation chamber has a smooth surface design. Heat exchange devices such as heat dissipation fins and liquid cooling plates can be stacked on the outer periphery of the circular heat pipe to further improve heat dissipation efficiency. At the same time, the number, diameter, and size of the condensation chamber of the circular heat pipe can be flexibly selected according to the heat flux density of the heat source. During assembly, after the open end of the circular heat pipe is inserted into the outer flange insertion hole of the cover plate 13, a sealed connection is achieved by brazing. After the circular heat pipe passes through the cover plate 13, it is connected to the connector 10 inside the hot plate 1, so that the chamber of the hot plate 1 and the condensation chamber of the circular heat pipe are connected to form a vacuum chamber. The chamber is filled with pure water as a phase change working fluid. The chamber of the hot plate 1 acts as an evaporation chamber, responsible for absorbing heat from the heat source and vaporizing the working fluid. The condensation chamber of the circular heat pipe is responsible for transporting the vapor to a distant end for heat dissipation and liquefaction.

[0030] Please refer to Figures 2, 3, and 6. The connector 10 and the flow guide 11 are integrated into the cavity of the hot plate 1, forming an independent working fluid collection system together with the liquid storage capillary structure 12, and the working fluid is returned by gravity. The connector 10 includes a sleeve 101, a disc 102, and multiple support columns 103. The sleeve 101 is a hollow cylindrical structure, and a circular heat pipe is inserted into the sleeve 101, allowing steam to flow between the hot plate 1 and the cooling element 2. The disc 102 is fitted around the outer periphery of the sleeve 101, and a flow guide groove 100 is formed around the sleeve 101 on the surface of the disc 102. The flow guide groove 100 can be a groove or a channel, and the surface of the flow guide groove 100 is a smooth plane. The outer periphery of the connector 10 is also a smooth plane. The flow channel 100 is a flat surface or an inclined flow channel with a surface guide element 11. Gravity guides the condensate to flow in a directional direction to the guide element 11. The inclined flow channel can accelerate the flow of the liquid working fluid to the guide element 11 using gravity, preventing the working fluid from remaining in the flow channel. The smooth transition design between the inclined surface and the heat pipe opening eliminates the liquid resistance zone and increases the outflow velocity of the condensate. The inclination angle of the inclined flow channel can be set to 5°~15°. When the angle is less than 5°, the effect of gravity is not significant and cannot effectively increase the conveying speed; when the angle is greater than 15°, it will weaken the structural strength of the joint 10 and cannot meet the reliability requirements of long-term hot and cold cycles. In specific implementation, the inclined surface can be directly formed by a customized stamping die or the inclination angle can be preset at the corresponding position of the sintering die, and integrally formed by powder metallurgy sintering, eliminating the need for subsequent machining and reducing manufacturing costs. Support columns 103 are distributed at the bottom of the plate 102 to support the plate 102 above the base plate 14, ensuring a steam flow gap between the plate 102 and the base plate 14. The material of the connector 10 can be selected according to the material of the hot plate 1 and the cooling component 2. If the hot plate 1 and the cooling component 2 are made of copper, oxygen-free copper is preferred, as its thermal conductivity is close to that of the base material, which can reduce thermal resistance loss and has excellent compatibility with copper solder paste brazing and diffusion welding, ensuring the reliability of vacuum sealing. If a lightweight design is desired, when the hot plate 1 and the cooling component 2 are made of aluminum, 6061 aluminum alloy can be selected, and a sealed connection can be achieved through aluminum-silicon solder, balancing structural strength and weight reduction requirements. In another embodiment, the outer periphery of the connector 10 located below the plate 102 can have a hollow structure, in which case the support column 103 structure can be omitted.

[0031] To accommodate the technical solution of fully covering the surface of the base plate 14 with the liquid storage capillary structure 12, the flow guide 11 includes a flow guide tube and several support blocks. The support blocks are fixed to the inner surface of the base plate 14 by welding intervals. The support blocks also have grooves for placing the flow guide tubes. After the flow guide tubes are installed and fixed in the grooves, they are suspended inside the chamber to prevent obstruction of the flow of liquid working fluid on the surface of the base plate 14. The cross-sectional shape of the flow guide tube can be designed as circular, square, or irregular according to the spatial layout and hydrodynamic requirements within the vacuum chamber of the hot plate 1. It has an inclined flow channel facing the liquid storage capillary structure 12 to ensure smooth return of the condensate by gravity. Correspondingly, the flow guide tube can be bridged and matched with multiple accessories to adapt to different layouts. The support blocks can be independent block structures, fixed to the bottom of the hot plate 1 by welding, brazing, or other reliable connection methods. The support blocks are spaced apart at the bottom of the hot plate 1. This spacing is designed to ensure that the guide tube has sufficient support points, while allowing the working fluid or other gases to flow freely between the support blocks, avoiding the formation of fluid dead zones or hindering the effective transfer of heat at the bottom of the hot plate 1.

[0032] Correspondingly, as shown in Figure 5, if the liquid storage capillary structure 12 is only set in the area of ​​the heat source action surface of the base plate 14 or integrated in the groove of the base plate 14, the flow guide 11 includes a flow guide tube. The flow guide tube is a metal bent tube structure, which is fixed to the surface of the base plate 14 by welding, brazing or other reliable connection methods. The surface is a smooth surface and does not bear the work of conveying the working fluid. Therefore, even if the flow guide tube is attached to the surface of the base plate 14, it will not affect the directional flow of the working fluid.

[0033] In this embodiment, when the hot plate 1 is horizontally attached to the surface of the heat source, the liquid working fluid stored in the liquid storage capillary structure 12 is heated and vaporized. The vapor enters the condensation chamber of the circular heat pipe through the connector 10. The vaporized working fluid releases heat and condenses into a liquid state inside the circular heat pipe, flowing back to the open end of the circular heat pipe by gravity. The condensate flows back to the liquid storage capillary structure 12 through the inclined flow channel of the guide pipe via the flow channel 100 of the connector 10, completing the complete cycle of evaporation, transportation, condensation and reflux, continuously carrying away the heat generated by the heat source.

[0034] As shown in Figure 6, Example 2 is designed for high heat flux density heat dissipation scenarios and scenarios where the hot plate 1 is not installed horizontally. The difference between Example 2 and Example 1 is that the inner top surface of the hot plate 1 and the condensation cavity of the cooling component 2 are provided with capillary passages. The rest of the structure and working principle are the same as those of Example 1.

[0035] Specifically, the side of the cover plate 13 facing the base plate 14 forms a second capillary structure layer through a process of sintering copper powder, copper mesh, or copper braided strip. This helps the steam to diffuse evenly within the hot plate 1, avoiding hot spots caused by localized steam accumulation. The inner wall of the condensation chamber of the circular heat pipe forms a fourth capillary structure layer 20 through the same process described above, thereby enhancing the heat exchange efficiency between the steam and the pipe wall and accelerating the liquefaction process of the working fluid.

[0036] Furthermore, when the first, second, and fourth capillary layers 20 are sintered using copper powder, the copper powder parameters and sintering parameters can be the same or different to form the same or different pore size, porosity, permeability, and equivalent thermal conductivity. Alternatively, the aforementioned capillary structure can also be formed by sintering copper fibers or copper mesh.

[0037] Compared to the gravity reflux design of Embodiment 1, the hot plate 1 of Embodiment 2 can be understood as a heat spreader of the prior art, and the circular heat pipe can be understood as a heat pipe of the prior art. Through the added capillary structure, the steam condensation heat transfer coefficient can be increased by more than 40%, the capillary structure on the inner top surface of the hot plate 1 improves the temperature uniformity by 25%, and the overall thermal conductivity is increased by 30%-50% compared with Embodiment 1. For the scenario of horizontal installation of the hot plate 1, it can be adapted to higher heat flux density. The basic structural design of the liquid storage capillary structure 12, the connector 10 and the flow guide 11 of Embodiment 2, as well as the core principle of working fluid circulation, are completely consistent with those of Embodiment 1, and will not be repeated here.

[0038] As shown in Figure 7, Example 3 is designed for vertical and inclined installation environments. Based on Example 2, a third capillary structure layer 16 is added to the flow channel 100 of the connector 10, and a capillary core 17 is provided at the connection between the connector 10 and the cooling component 2. This allows the third capillary structure layer 16, the capillary core 17, and the fourth capillary structure layer 20 to contact and communicate with each other. Simultaneously, the flow channel structure of the guide component 11 also has a fifth capillary connection structure 18, forming a continuous capillary path from the cooling component 2 to the hot plate 1. Combined with the second capillary structure layer on the inner top surface of the hot plate 1, a complete capillary drive system for evaporation, transmission, condensation, and reflux is constructed. In specific implementations, when the third capillary structure layer 16, the capillary core 17, the fifth capillary connection structure 18, and the fourth capillary layer 20 are made of sintered copper powder, the porosity can reach 60%-80%, exhibiting strong liquid absorption capacity and excellent thermal conductivity, making it suitable for high heat flux density concentrated heat dissipation scenarios. When using copper mesh / copper braided tape, the device exhibits good flexibility, can tightly conform to complex curved cavities, has low processing difficulty, and is suitable for mass production scenarios. Compared to Example 2, Example 3 can rely on capillary force to drive the working fluid recirculation, is not limited by the installation posture, and can achieve recirculation against gravity.

[0039] Furthermore, when the third capillary layer 16, capillary core 17, fifth capillary connection structure 18, and fourth capillary layer 20 are sintered using copper powder, the copper powder parameters and sintering parameters can be the same or different to form the same or different pore size, porosity, permeability, and equivalent thermal conductivity. Alternatively, the aforementioned capillary structure can also be formed by sintering copper fibers or copper mesh.

[0040] The basic structural design of the liquid storage capillary structure 12, connector 10 and flow guide 11 in this embodiment 3, as well as the core principle of working fluid circulation, are completely consistent with those in embodiment 1 or embodiment 2, and will not be repeated here.

[0041] Example 4, as shown in Figures 8 to 10, is designed for heat dissipation in compact spaces. The difference from Example 3 is that the cooling component 2 uses a square metal tube structure, and the connector 10 is designed as a square adapter interface. The remaining structure and working principle are consistent with Example 1, specifically as follows: Unlike the circular heat pipe in Example 1, the cooling component 2 in this example is a square heat pipe, also made of high thermal conductivity copper or lightweight aluminum alloy. This allows for denser heat dissipation fins or liquid cooling channels, enhancing heat exchange efficiency on the air or liquid side. Simultaneously, the square heat pipe structure better fits the internal layout of compact devices such as server chassis and communication base stations, reducing the required installation space. In Example 3, the inner wall of the condensation chamber of the square heat pipe can be made smooth or have a capillary structure, consistent with the working fluid circulation logic of Example 2. Correspondingly, the sleeve 101 portion of the connector 10 is a square hollow structure matching the inner cross-section of the square heat pipe, ensuring maximum steam flow cross-section. The disc body 102 is designed with a square structure. A rectangular annular drainage groove 100 is formed around the outer periphery of the square sleeve 101. The drainage groove 100 retains an inclined drainage surface facing the flow guide 11 to ensure that the condensate can flow smoothly to the flow guide 11. Three support columns 103 are evenly arranged at the bottom of the square disc body 102 to ensure the steam flow gap between the disc body 102 and the base plate 14, and to avoid deformation of the square structure due to uneven stress.

[0042] Furthermore, if the height of the square heat pipe is relatively low (e.g., height ≤ 30mm), the square heat pipe can also be integrally formed with the cover plate 13. In this configuration, the integral forming of the square heat pipe and the cover plate 13 eliminates the weld seam of the welding / brazing connection, avoiding the weld seam cracking and sealing failure problems that are prone to occur in the cold and hot cycles of traditional connection methods, which can effectively improve the structural reliability; at the same time, the integrated structure reduces the interface thermal resistance and improves the heat dissipation efficiency. Moreover, it can eliminate the positioning, welding, and leak detection processes of the square heat pipe and the cover plate 13, shorten the assembly time, and has the advantage of reducing mass production costs.

[0043] It is understandable that the structure of the cooling component 2 can be flexibly expanded. In addition to the circular tube and directional heat pipe structure in the above embodiments, it can also adopt a non-circular tube structure (such as an elliptical tube or a flat tube) or a shell structure (such as a rectangular cavity or a non-circular cavity), as long as it has an independent condensation chamber inside and can realize the function of steam exothermic liquefaction.

[0044] In this embodiment 3, the flow channel 100 of the connector 10 can also be equipped with a third capillary structure layer 16, and a capillary core 17 can also be provided at the connection between the connector 10 and the cooling component 2. In this embodiment 4, the adaptation design of the square heat pipe and the square connector 10 is particularly suitable for heat dissipation of high-density electronic devices with limited space. The structure of the hot plate 1, the liquid storage capillary design, the layout of the flow guide 11, and the working fluid circulation principle of this embodiment 4 are completely consistent with those of embodiment 1, and will not be repeated here.

[0045] In summary, the 3DVC radiator with an independent working fluid return path provided in this application solves the reliability problem caused by the reliance on the capillary structure return of the base plate 14 or cover plate 13 in traditional 3DVC radiators with independent working fluid return paths by constructing an independent dedicated return channel inside the evaporation chamber. At the same time, it achieves a dual breakthrough in thermal conductivity and structural stability, specifically in the following aspects: (1) It can solve the high and low temperature cycle reliability problem. By separating the collection and return function of condensate from the capillary structure of the base plate 14 and cover plate 13 through the independent return channel, the working fluid accumulation in the base plate 14, cover plate 13 and cooling component 2 is greatly reduced. In high and low temperature thermal shock and temperature cycle tests, it can avoid the bulging and deformation of the base plate 14, cover plate 13 or cooling component 2 caused by the volume expansion of the working fluid due to freezing, and block the failure path of capillary structure damage, so that the 3DVC radiator with an independent working fluid return path can stably pass the stringent reliability test, and improve the product service life and environmental adaptability.

[0046] (2) It can balance the dual requirements of high thermal conductivity and structural stability. For the high heat flux density thermal conductivity requirement of high power consumption chips, this solution optimizes the distribution of working fluid through an independent return channel under the premise that the water content saturation of the working fluid exceeds 90%, thus avoiding the contradiction between high water content and reliability in the traditional solution. The third capillary structure layer 16 and the fourth capillary structure layer 20 of the flow channel 100 are directly connected. With the directional guidance of the flow guide 11, a dedicated path for efficient return of working fluid is constructed, which not only ensures thermal conductivity but also eliminates the risk of bulging from the root.

[0047] (3) It is compatible with existing manufacturing processes and reduces mass production costs. The connector 10, the flow guide 11 and the liquid storage capillary structure 12 can be prefabricated and assembled. It can be seamlessly connected with the stamping, sintering and welding processes of traditional 3DVC heat sinks with independent working fluid return paths. Mass production can be achieved without significant adjustments to the existing production line.

[0048] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A 3DVC heatsink with an independent working fluid return path, characterized in that, The device includes a hot plate and at least one cooling component with a condensation chamber. The hot plate has a connector and a flow guide inside. The cooling component is connected to the chamber of the hot plate through the connector, and the chamber and the condensation chamber form a vacuum chamber. The connector has a flow channel, which is connected to the open end of the condensation chamber. The inner bottom surface of the hot plate is provided with a liquid storage capillary structure. The flow channel and the liquid storage capillary structure form a working fluid circulation path through the flow guide.

2. The 3DVC heatsink with an independent working fluid return path according to claim 1, characterized in that, The hot plate includes a cover plate and a bottom plate. The cover plate is sealed and closed on the bottom plate, and the cover plate and the bottom plate enclose the cavity. The bottom plate is provided with a plurality of support members that abut against the cover plate.

3. The 3DVC heat sink with an independent working fluid return path according to claim 2, characterized in that, The liquid storage capillary structure is a first capillary structure layer disposed on the inner surface of the base plate; the side of the cover plate facing the base plate is a smooth surface, or is provided with a second capillary structure layer.

4. The 3DVC heat sink with an independent working fluid return path according to claim 3, characterized in that, The surface of the base plate facing the cover plate is either flat or has a groove.

5. The 3DVC heat sink with an independent working fluid return path according to claim 2, characterized in that, The cooling component includes either a circular heat pipe or a square heat pipe. If the cooling component is a circular heat pipe, it is brazed to the cover plate. If the cooling component is a square heat pipe, it is integrally formed or brazed to the base plate.

6. The 3DVC heat sink with an independent working fluid return path according to claim 1, characterized in that, The drainage channel is provided with an inclined drainage surface facing the drainage component.

7. The 3DVC heat sink with an independent working fluid return path according to claim 6, characterized in that, The drainage channel is provided with a third capillary structure layer, the connection between the connector and the cooling component is provided with a capillary core, and the inner wall of the condensation chamber of the cooling component is provided with a fourth capillary structure layer; the third capillary structure layer, the capillary core and the fourth capillary structure layer are in contact with each other and connected to form a continuous capillary passage.

8. The 3DVC heat sink with an independent working fluid return path according to claim 7, characterized in that, The flow guide is provided with a fifth capillary connection structure, which is connected to the third capillary structure layer and the liquid storage capillary structure respectively; the forming methods of the third capillary structure layer, the fifth capillary connection structure, and the capillary core include any one of sintered copper powder, copper mesh, and copper braided tape.

9. The 3DVC heat sink with an independent working fluid return path according to claim 1, characterized in that, The connector includes a sleeve, a disc, and multiple support columns. The disc is sleeved around the outer periphery of the sleeve, and the drain groove is formed around the surface of the disc around the sleeve. The support columns are located at the bottom of the disc.

10. The 3DVC heatsink with an independent working fluid return path according to claim 1, characterized in that, The flow guide includes a flow guide tube and several support blocks; the support blocks are spaced apart on the inner bottom surface of the hot plate, and the flow guide tube is mounted above the support blocks; the flow guide tube has an inclined flow channel facing the liquid storage capillary structure.

Images