Ultrathin vapor chamber based on bionic capillary core

Abstract

The invention belongs to the technical field of heat dissipation devices, and particularly discloses an ultrathin vapor chamber based on a bionic capillary wick, which comprises a lower cover plate, a primary wick, a bionic secondary wick and an upper cover plate. The lower cover plate is provided with a cavity, and the cavity is filled with a liquid working medium; the primary wick is laid on the inner bottom surface of the cavity; the bionic secondary wick is laid on the top surface of the primary wick; the upper cover plate is connected to the top of the lower cover plate, and the primary wick and the bionic secondary wick are sealed in a cavity of the lower cover plate. Wherein the first-stage liquid absorption core and the bionic second-stage liquid absorption core are of the same or different porous medium structures, and the ultrathin vapor chamber is sequentially divided into an evaporation area, a heat insulation area and a condensation area in the length direction of the ultrathin vapor chamber. Through the synergistic effect of the multi-stage wick, the subarea design of the super-hydrophilic and super-hydrophobic structure and the gradient design of the bionic capillary wick, the capillary pressure is effectively enhanced, the liquid backflow rate is increased, the condensation heat transfer performance is optimized, and the advantages that the heat transfer limit is increased, and the condensation heat resistance is reduced are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of heat dissipation devices, and particularly to an ultra-thin vapor chamber based on a bionic wick. Background Art

[0002] With the wide application of 5G portable intelligent devices, electronic devices are rapidly developing towards high power and miniaturization. Under this trend, the internal space of electronic devices becomes extremely narrow, which greatly limits the size of heat dissipation components. Therefore, how to efficiently dissipate heat with a high heat flux density in a narrow space has become a key problem to be solved urgently.

[0003] Among many heat dissipation solutions, the ultra-thin vapor chamber with a total thickness less than 1 mm has gradually become an important choice in the heat dissipation field of 5G portable intelligent devices due to its significant advantages such as high thermal conductivity, good temperature uniformity, small volume, and compact structure. However, when the total thickness of the ultra-thin vapor chamber is further reduced to less than 0.6 mm, after removing the wall thickness of the upper cover plate, the lower cover plate, and the thickness occupied by the vapor channel, the thickness of the wick will become extremely limited. This results in a significant reduction in the capillary force of the wick and a substantial increase in the flow resistance. In this case, the reflux condensate working fluid in the evaporation region is prone to insufficiency, while the condensate is likely to accumulate in the condensation region. These phenomena not only reduce the heat transfer limit of the ultra-thin vapor chamber but also increase the condensation heat transfer resistance, seriously affecting its heat dissipation performance and restricting its application in thinner and higher power density devices.

[0004] In view of this, there is an urgent need for an ultra-thin vapor chamber based on a bionic wick to solve the above problems. Summary of the Invention

[0005] The present invention aims to provide an ultra-thin vapor chamber based on a bionic wick to solve the above technical problems and achieve the purpose of increasing the heat transfer limit of the ultra-thin vapor chamber and reducing the condensation heat resistance.

[0006] To achieve the above purpose, the present invention provides the following solution: An ultra-thin vapor chamber based on a bionic wick, comprising:

[0007] A lower cover plate, which is provided with a cavity filled with a liquid working fluid;

[0008] A primary wick, laid on the inner bottom surface of the cavity;

[0009] A bionic secondary wick, laid on the top surface of the primary wick;

[0010] An upper cover plate, connected to the top of the lower cover plate, sealing the primary wick and the bionic secondary wick in the cavity of the lower cover plate;

[0011] The first-level wick and the bionic second-level wick are the same or different porous medium structures;

[0012] The ultra-thin vapor chamber is sequentially divided into an evaporation zone, an adiabatic zone, and a condensation zone along its length direction.

[0013] Preferably, the bionic second-level wick includes 2-15 bionic capillary wicks arranged at equal intervals along the width direction of the ultra-thin vapor chamber. The arrayed bionic capillary wicks improve the liquid transport efficiency, prevent the condensate from accumulating in local areas, and avoid the dry-out phenomenon in the evaporation zone due to insufficient liquid supply, thus ensuring the stable heat dissipation performance of the vapor chamber under extreme thickness conditions.

[0014] Preferably, the width of the bionic capillary wick gradually and smoothly widens from the condensation zone to the evaporation zone, presenting an isosceles trapezoid structure. The gradually changing expansion feature of the isosceles trapezoid structure makes the capillary pressure distribution in different regions of the capillary wick more match the actual working conditions requirements, thereby improving the heat transfer efficiency of the vapor chamber under high heat flux density conditions.

[0015] Preferably, the porous surface of the first-level wick in the evaporation zone has a super-hydrophilic micro-nano structure, the porous surface of the first-level wick in the adiabatic zone near the evaporation zone has a super-hydrophilic micro-nano structure, the lower porous surface of the first-level wick in the condensation zone has a super-hydrophilic micro-nano structure, the lower porous surface of the first-level wick in the adiabatic zone near the condensation zone has a super-hydrophilic micro-nano structure, the upper porous surface of the first-level wick in the condensation zone has a super-hydrophobic micro-nano structure, and the upper porous surface of the first-level wick in the adiabatic zone near the condensation zone has a super-hydrophobic micro-nano structure. This solution optimizes the condensate discharge path while maintaining a high capillary force through the zoned design of super-hydrophilic and super-hydrophobic structures.

[0016] Preferably, the bionic capillary wick has a triangular serrated structure with alternating left and right sides on both sides above the super-hydrophobic micro-nano structure of the first-level wick. This solution creates a spontaneous liquid droplet migration path by constructing an asymmetric serrated structure on both sides of the super-hydrophobic region, avoiding the accumulation and blockage of condensate at the edge of the capillary wick.

[0017] Preferably, the porous surface of the bionic second-level wick has a super-hydrophilic micro-nano structure. This structure can reduce the liquid flow resistance and accelerate the penetration and diffusion of the working fluid in the pores.

[0018] Preferably, the material of the first-level wick and / or the bionic second-level wick includes one or more of sintered copper powder, wire mesh, and copper foam. The above structure significantly improves the liquid working fluid reflux efficiency through the selection and combination of materials, avoids the phenomena of insufficient liquid supply in the evaporation zone and liquid accumulation in the condensation zone, thereby increasing the heat transfer limit and reducing the condensation heat resistance, providing reliable capillary power support for vapor chambers with a thickness less than 0.6 mm.

[0019] Preferably, the upper cover plate and the lower cover plate are made of the same material, both of which are metal materials.

[0020] Preferably, the upper cover plate and the lower cover plate are made of copper, aluminum or stainless steel.

[0021] Preferably, the liquid working medium is one of water, acetone, alcohols, and aqueous alcohol solutions.

[0022] Compared with the prior art, the present invention discloses at least the following beneficial effects: The ultra-thin vapor chamber of the present invention has a porous medium structure with a primary wick and a bionic secondary wick. By dividing the evaporation zone, the adiabatic zone and the condensation zone, and combining the gradient design of the super-hydrophilic-super-hydrophobic micro-nano structure and the bionic capillary wick, the capillary pressure is effectively enhanced, the liquid reflux rate is increased, and the condensation heat transfer performance is optimized, having the advantages of improving the heat transfer limit and reducing the condensation thermal resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1 Structural schematic of the ultra-thin vapor chamber based on the bionic capillary wick of the present invention Figure 1 ;

[0025] Figure 2 Structural schematic of the ultra-thin vapor chamber based on the bionic capillary wick of the present invention Figure 2 ;

[0026] Figure 3 Front structural schematic diagram of the ultra-thin vapor chamber based on the bionic capillary wick of the present invention;

[0027] Figure 4 Front assembly drawing of the ultra-thin vapor chamber based on the bionic capillary wick of the present invention;

[0028] Figure 5 Top view of the internal structure of the present invention after removing the upper cover plate.

[0029] In the figure: 1. Upper cover plate; 2. Lower cover plate; 3. Primary wick; 4. Bionic secondary wick; 41. Bionic capillary wick; 42. Triangular serrated structure; 5. Condensation zone; 6. Adiabatic zone; 7. Evaporation zone. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] In the prior art, with the development of high power and miniaturization of portable intelligent devices, heat dissipation components need to achieve efficient heat conduction in a limited space. When the thickness of traditional ultra-thin vapor chambers is further reduced, the capillary force of the wick significantly decreases, resulting in the inability of the condensed liquid to flow back to the evaporation zone 7 in time. At the same time, the steam flow resistance increases, ultimately leading to a decrease in heat transfer efficiency and an increase in thermal resistance.

[0032] To solve the above problems, by analyzing the contradictory relationship between capillary force and flow resistance under thin-film conditions, as well as the flow characteristics of the liquid working medium in the ultra-thin cavity, it is found that a single wick structure is difficult to simultaneously meet the requirements of capillary force improvement and flow resistance reduction. For this reason, it is proposed to optimize the liquid transport path through the synergistic effect of multi-stage wicks. Further considering the driving effect of the surface energy gradient on the directional flow of the liquid, the combined design of super-hydrophilic and super-hydrophobic regions is explored.

[0033] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Refer to Figures 1 to 5 As shown, the present invention provides an ultra-thin vapor chamber based on a bionic wick, including a lower cover plate 2, an upper cover plate 1, a primary wick 3, and a bionic secondary wick 4. A sealed cavity for filling the liquid working medium is formed inside the lower cover plate 2. The primary wick 3 covers the bottom surface of the cavity, and the bionic secondary wick 4 is superimposed on the surface of the primary wick 3. The ultra-thin vapor chamber is divided into an evaporation zone 7, an adiabatic zone 6, and a condensation zone 5 along the length direction, and the wick adopts a porous medium structure. Among them, the cavity of the lower cover plate 2 is a closed space for accommodating the liquid working medium and performing phase change heat transfer, which can be specifically formed by stamping or etching processes, and its depth is adapted to the heat dissipation requirements of the device. The primary wick 3 is a basic capillary structure laid on the bottom surface of the cavity, used to provide basic capillary force and guide the liquid distribution. The bionic secondary wick 4 is an auxiliary capillary structure superimposed on the surface of the primary wick 3, and its morphology mimics the hierarchical characteristics of biological capillary tissues, capable of forming supplementary liquid transport channels. The primary wick 3 and the bionic secondary wick 4 can adopt the porous medium structure of the same material or different materials. The porous medium structure is a permeable material with connected pores, and the porosity can be adjusted according to the properties of the working medium, which can not only maintain the capillary force but also control the flow resistance.

[0035] Specifically, the liquid working medium is heated and evaporated into steam in the evaporation zone 7, and the steam diffuses towards the condensation zone 5 through the adiabatic zone 6. The condensed liquid accelerates its reflux through the directional structure of the bionic secondary wick 4, while the base structure of the primary wick 3 ensures uniform liquid distribution. The layered design of the porous medium forms a composite capillary channel, which not only increases the liquid contact area but also reduces the flow resistance through the pore gradient. The functional division between the evaporation zone 7 and the condensation zone 5 optimizes the phase change heat transfer path, and the adiabatic zone 6 provides a low-resistance channel for steam flow.

[0036] Compared with the prior art, the traditional single-layer wick structure faces the contradiction between capillary force and thickness limitation during thinning, while the layered-designed wick can achieve capillary force superposition within a limited space. In the prior art, the homogeneous porous structure is prone to form flow dead zones, and the bionic hierarchical structure improves the liquid transport efficiency by optimizing the pore distribution. In addition, the prior solutions do not consider the functional differentiation of different regions, and this solution achieves the directional optimization of the heat transfer path through zone design.

[0037] Through the above technical solutions, this embodiment maintains an effective capillary driving force under ultra-thin conditions, ensuring that the condensed liquid can timely reflux to the evaporation zone 7, avoiding local dryness or liquid accumulation. The synergistic effect of the multi-stage wick reduces the flow resistance of the working medium and improves the phase change heat transfer efficiency. The zone structure design optimizes the spatial distribution of steam diffusion and liquid reflux, enhancing the temperature uniformity of the heat sink. While maintaining an ultra-thin thickness, this structure significantly improves the stability of the heat dissipation performance.

[0038] In a further optimized solution, the bionic secondary wick 4 includes 2 - 15 bionic capillary wicks 41 arranged at equal intervals along the width direction of the ultra-thin heat sink. In a specific embodiment, as Figure 1 shown, the bionic secondary wick 4 of this application includes 3 bionic capillary wicks 41 arranged at equal intervals along the width direction of the ultra-thin heat sink.

[0039] Specifically, the bionic capillary wick 41 is a porous medium structure formed by mimicking the liquid transport mechanism of organisms, and can be specifically realized by sintering copper powder with a trapezoidal pore structure. The liquid transport ability is enhanced through bionic design. The bionic capillary wick 41 can be specifically realized by laser cutting or die forming processes. Each bionic capillary wick 41 maintains a uniform interval distribution in the width direction, and optimizes the circulation path of the liquid working medium between the evaporation zone 7 and the condensation zone 5 through regular arrangement.

[0040] In a heat pipe with a total thickness of less than 0.6 mm, when the thickness of the wick is limited and the capillary force is insufficient, by arranging multiple parallel bionic capillary cores 41, the capillary pressure per unit area can be increased without increasing the overall thickness. The bionic capillary cores 41 are evenly distributed in the width direction, so that after the liquid working medium is heated and vaporized in the evaporation zone 7, the condensate can flow back synchronously along the independent paths of the bionic capillary cores 41, avoiding liquid retention caused by excessive local flow resistance. At the same time, the equal-spacing arrangement makes the vapor channels and the liquid return channels form an interleaved distribution, effectively separating the gas-liquid two-phase flow paths.

[0041] Compared with the prior art, traditional heat pipes mostly adopt a single-layer continuous wick structure, which is prone to liquid reflux hysteresis due to insufficient capillary force under ultra-thin conditions. However, in this solution, through the discrete bionic capillary core 41 array, while maintaining the structural strength, multiple independent capillary pumping units are formed, enabling the local capillary pressure to be superimposed, and the edge effect generated by the discrete arrangement can accelerate the diffusion of the liquid in the width direction. It solves the problem of insufficient liquid reflux capacity caused by the limited thickness of the wick in ultra-thin heat pipes.

[0042] In a further optimized solution, the width of the bionic capillary core 41 gradually and smoothly widens from the condensation zone 5 to the evaporation zone 7, presenting an isosceles trapezoidal structure. Among them, the isosceles trapezoidal structure is a gradually changing and expanding form with bilateral symmetry in the width direction of the capillary core. Specifically, gradient processing of the porous medium can be achieved by using laser cutting or stamping processes. This structure enhances the capillary transport capacity of the liquid working medium at the evaporation end by increasing the cross-sectional area of the capillary core in the evaporation zone 7. Among them, the smooth widening means that there is no sudden change or step during the width change. Specifically, the flow path of the fluid in the capillary core can be controlled by continuously changing geometric design parameters, thereby reducing the flow resistance.

[0043] Specifically, the bionic capillary core 41 with an isosceles trapezoidal structure maintains a relatively narrow width at the starting position of the condensation zone 5 and gradually expands as it extends to the evaporation zone 7. This design makes the liquid working medium channels of the capillary core form a diffused distribution at the evaporation end, which helps to increase the coverage area of the liquid working medium in the high-temperature region. During the liquid reflux process, the gradually widening channel structure can generate a capillary pressure gradient, guiding the condensate to flow directionally towards the evaporation zone 7 along the trapezoidal inclined plane direction. For example, when the heat pipe is working, the liquid working medium accumulated in the condensation zone 5 can be evenly dispersed to the expanded area of the evaporation zone 7 through the lateral guiding effect of the trapezoidal structure.

[0044] Compared with the prior art, the parallel straight capillary wick of the traditional heat pipe is prone to problems such as a single flow path and uneven liquid distribution during the reflux of the condensate. In this solution, an isosceles trapezoid structure is used to form an asymmetric capillary force distribution, which provides a larger penetration space for the liquid working medium in the evaporation zone 7 while maintaining the overall structural strength of the capillary wick. Compared with the conventional capillary wick with equal width, this structure can effectively prevent the local accumulation of liquid at the evaporation end and reduce the pressure drop loss during the flow process. Based on this structure, the present application enhances the diffusion ability of the liquid working medium in the evaporation zone 7 and improves the distribution uniformity of the condensate reflux path.

[0045] In a further optimized solution, the porous surface of the first-stage liquid absorption wick 3 in the evaporation zone 7 has a super-hydrophilic micro-nano structure, the porous surface of the first-stage liquid absorption wick 3 in the adiabatic zone 6 close to the evaporation zone 7 has a super-hydrophilic micro-nano structure, the lower porous surface of the first-stage liquid absorption wick 3 in the condensation zone 5 has a super-hydrophilic micro-nano structure, the lower porous surface of the first-stage liquid absorption wick 3 in the adiabatic zone 6 close to the condensation zone 5 has a super-hydrophilic micro-nano structure, the upper porous surface of the first-stage liquid absorption wick 3 in the condensation zone 5 has a super-hydrophobic micro-nano structure, and the upper porous surface of the first-stage liquid absorption wick 3 in the adiabatic zone 6 close to the condensation zone 5 has a super-hydrophobic micro-nano structure. The super-hydrophilic micro-nano structure is specifically a micro-nano scale roughened structure with a surface contact angle less than 10 degrees, which can be achieved by chemical oxidation or nano-particle coating process. By enhancing the wettability of the liquid on the surface of the capillary wick, the capillary suction force is improved. The super-hydrophobic micro-nano structure is specifically a micro-nano scale composite structure with a surface contact angle greater than 150 degrees, which can be achieved by fluoro-silane modification or low surface energy material deposition process. By suppressing the spreading of the liquid on the surface, the formation of dropwise condensation is promoted.

[0046] Specifically, in the evaporation zone 7 and the adjacent adiabatic zone 6, the super-hydrophilic micro-nano structure accelerates the directional transportation of the liquid from the condensation zone 5 to the evaporation zone 7 by enhancing the capillary penetration ability of the liquid working medium, avoiding local dryness in the evaporation zone 7 due to insufficient working medium. In the upper layer of the condensation zone 5 and the adjacent adiabatic zone 6, the super-hydrophobic micro-nano structure reduces the liquid film coverage area, promotes the rapid detachment of the condensate in the form of discrete droplets from the surface, and reduces the condensation heat transfer resistance. At the same time, the super-hydrophilic structure in the lower layer of the condensation zone 5 and the super-hydrophobic structure in the upper layer form a surface energy gradient, driving the condensate to migrate from the low-energy region to the high-energy region, further improving the working medium circulation efficiency.

[0047] Compared with the prior art, the liquid absorption wick of the traditional heat pipe usually adopts a single wettability structure, which cannot meet the requirements of both enhancing the capillary force at the evaporation end and the rapid detachment of droplets at the condensation end. In the prior art, the heat transfer efficiency in the condensation zone 5 often decreases due to the continuous liquid film coverage. However, in this solution, the super-hydrophilic and super-hydrophobic structures are designed in different zones, optimizing the condensate discharge path while maintaining a high capillary force.

[0048] Through the above technical solution, the present application effectively solves the problems of reduced working fluid reflux rate and condensate retention caused by insufficient wick thickness after the thickness reduction of the ultra-thin vapor chamber. Through surface energy gradient driving and zonal wettability control, efficient circulation of the liquid working fluid is achieved, the heat transfer limit is increased, and the condensation thermal resistance is reduced.

[0049] In a further optimized solution, on both sides of the bionic wick 41 above the superhydrophobic micro-nano structure of the primary wick 3, there are triangular serrated structures 42 arranged alternately left and right. The triangular serrated structure 42 is a periodic concave-convex contour formed along the two side edges of the wick, which can be specifically realized by laser cutting or chemical etching. This structure guides the directional migration of droplets through the surface tension gradient. Among them, the superhydrophobic micro-nano structure is a microscopically rough surface with a contact angle greater than 150 degrees, which can be specifically formed by anodization combined with fluorosilane modification. This structure can reduce the droplet adhesion force and promote the rolling effect.

[0050] Specifically, in the condensation zone 5, when droplets are formed on the surface of the superhydrophobic micro-nano structure, a local capillary pressure difference will be generated at the tip of the triangular serrations. This pressure difference prompts the droplets to move directionally towards the evaporation zone 7 along the direction of the serration arrangement. At the same time, a liquid film transport channel is formed in the concave area between adjacent serrations. Through the periodically arranged serrated structure, a continuous surface energy gradient field can be established, effectively overcoming the droplet retention phenomenon existing in the traditional planar structure.

[0051] Compared with the prior art, the edges of the wicks of conventional vapor chambers mostly adopt straight or arc-shaped contours, which cannot form an effective droplet guiding mechanism. In this solution, an asymmetric serrated structure is constructed on both sides of the superhydrophobic region, creating a spontaneous droplet migration path and avoiding the accumulation and blockage of condensate at the wick edge. Based on this structure, the present application effectively solves the problem of increased thermal resistance caused by condensate retention under the limit thickness condition of the ultra-thin vapor chamber, enhances the reflux driving force of the liquid working fluid through the structured surface topography design, and thus improves the phase change heat transfer efficiency. This solution is particularly suitable for the application scenario of micro vapor chambers with a thickness less than 0.6 mm.

[0052] In a further optimized solution, for the ultra-thin vapor chamber based on the bionic wick, the porous surface of the bionic secondary wick 4 has a superhydrophilic micro-nano structure. The porous surface of the bionic secondary wick 4 is a porous medium surface formed by micro-scale or nano-scale processing, which can be specifically realized by laser etching, chemical deposition or electrochemical anodization processes. This structure can enhance the capillary force and expand the contact area of the liquid working fluid. The superhydrophilic micro-nano structure is a microscopically roughened structure with a surface contact angle less than 10 degrees, which can be specifically realized by titanium dioxide nano-coating or silane coupling agent modification treatment. This structure can reduce the liquid flow resistance and accelerate the penetration and diffusion of the working fluid in the pores.

[0053] Specifically, after the porous surface of the bionic secondary liquid absorbent core 4 is covered with a super-hydrophilic micro-nano structure, a high capillary force driving path is formed in the condensation area 5. When the steam working medium condenses into liquid in the condensation area 5, the super-hydrophilic surface quickly adsorbs the liquid film into the pores through capillary action, and at the same time uses the surface energy gradient to promote the directional migration of the liquid to the evaporation area 7. This structure cooperates with the super-hydrophobic area of the primary liquid absorbent core 3 to form a surface tension difference, further enhance the working medium circulation efficiency, significantly improve the capillary pumping capacity, and optimize the distribution morphology of the liquid film to avoid excessive accumulation of condensate in local areas.

[0054] Further optimization scheme, the material of the primary absorbent core 3 and / or the biomimetic secondary absorbent core 4 includes one or more of sintered copper powder, wire mesh, and foamed copper. Among them, sintered copper powder is a porous structure material with a continuous pore network that is bonded by a high-temperature sintering process to copper powder particles. In a specific embodiment, copper powder with a particle size of 50-200 microns can be sintered in a reducing atmosphere, and its porosity can be controlled in the range of 40%-70%, thereby achieving a balance between high capillary force and liquid penetration rate. Among them, the wire mesh is a multi-layer mesh structure formed by weaving metal wires, and specifically, a copper wire mesh with a mesh size of 100-400 can be superimposed and pressed to form it. The pore distribution is optimized by adjusting the weaving density and the number of layers, thereby reducing the resistance to liquid flow. Among them, foamed copper is a three-dimensional interconnected porous metal material prepared by electrochemical deposition or gas foaming method, and specifically, a foamed copper matrix with a pore size of 0.05mm-0.2mm can be used. Its high specific surface area and through-holes can simultaneously enhance capillary suction capacity and vapor diffusion efficiency.

[0055] Specifically, in the ultra-thin heat spreader, the first-level absorbent core 3 is laid on the bottom surface of the cavity, and the bionic second-level absorbent core 4 is covered on top of it. When sintered copper powder is used as the absorbent core material, the micron-level pores evenly distributed inside it can quickly guide the liquid working medium to flow back from the condensation zone 5 to the evaporation zone 7 through capillary action. If a multi-layer copper wire mesh is used, an anisotropic pore structure can be formed by adjusting the superposition direction of the mesh layer, and the liquid transport rate is preferentially increased in the evaporation zone 7. When foam copper is used, its three-dimensional through-hole channel can reduce the steam flow resistance, and the surface super-hydrophilic treatment is used to enhance the capillary force. The above materials can be used alone or in combination in the first-level absorbent core 3 and the bionic second-level absorbent core 4, and the coordinated regulation of capillary force and flow resistance can be achieved in the ultra-thin space by optimizing the porosity, pore size distribution and permeability matching. Through the combined application of sintered copper powder, wire mesh and foam copper in this scheme, a complementary effect can be formed through differentiated pore structures. For example, the high porosity of sintered copper powder can enhance capillary pressure, the layered structure of the wire mesh can directionally guide the liquid, and the foamed copper can reduce the pressure drop of steam flow. The synergistic effect of the three breaks through the contradiction between capillary force and flow resistance under ultra-thin conditions.

[0056] For a further optimized solution, the upper cover plate 1 and the lower cover plate 2 are made of the same material, both of which are metallic materials with high thermal conductivity and high mechanical strength. Specifically, copper, aluminum, or stainless steel can be used. These materials can effectively transfer heat while ensuring the structural strength. The upper cover plate 1 and the lower cover plate 2 are made of the same material and casting process, which can ensure the consistency of the material's coefficient of thermal expansion and avoid structural deformation or seal failure caused by temperature changes.

[0057] For a further optimized solution, the upper cover plate 1 and the lower cover plate 2 are made of copper, aluminum, or stainless steel. Copper is a metallic material composed of pure copper or copper alloy. Specifically, rolled copper plates or stamped copper plates can be used to achieve it. Its high thermal conductivity is conducive to the rapid conduction of heat inside the heat pipe. Aluminum is a metallic material composed of pure aluminum or aluminum alloy. Specifically, anodized aluminum plates or forged aluminum plates can be used to achieve it. Its lightweight characteristic can reduce the overall weight of the heat pipe. Stainless steel is an alloy steel with a chromium content exceeding 10.5%. Specifically, 304 stainless steel or 316L stainless steel can be used to achieve it. Its high strength and corrosion resistance can improve the structural stability of the heat pipe.

[0058] In some specific embodiments, the thickness of the copper plate can be controlled within the range of 0.08 mm to 0.15 mm, and the cavity structure is formed by chemical etching; the aluminum plate can be 5052 aluminum alloy, and a surface insulation layer is formed by micro-arc oxidation treatment; the stainless steel plate can adopt the laser welding process and be encapsulated in a protective gas environment.

[0059] For a further optimized solution, the liquid working medium is one of water, acetone, and alcohols. Among them, the liquid working medium is the medium for heat transfer through the phase change cycle inside the heat pipe. Specifically, substances with different boiling points, surface tensions, and latent heats of vaporization can be used to achieve it. For example, water has high thermal conductivity and high latent heat of vaporization, which is suitable for medium and high temperature heat dissipation scenarios. Its high latent heat of vaporization can improve the heat transfer efficiency per unit volume; acetone has a low boiling point and high volatility, which is suitable for low temperature or rapid heat dissipation requirements. Its low boiling point characteristic can accelerate the phase change cycle rate; alcohol-based working media achieve a balance between surface tension and viscosity, which helps to reduce the flow resistance and maintain stable capillary reflux. The selection of these working media is based on the matching degree of their physical properties with the operating temperature range of the heat pipe. By optimizing the synergistic effect of the working medium and the wick structure, the capillary pressure gradient can be enhanced and the liquid reflux power can be improved.

[0060] Working principle of the embodiment of the present invention: The liquid working medium evaporates into steam on the side of the bionic secondary wick evaporation zone 7 and the top of the evaporation zone 7 of the primary wick 3. The steam diffuses through the cavity between the secondary wick strip structures to the adiabatic zone 6 and the condensation zone 5. After condensing into beaded liquid on the superhydrophobic surface of the condensation zone 5, it returns to the evaporation zone 7 under the capillary force jointly provided by the superhydrophilic structure of the primary wick 3, the superhydrophilic structure of the secondary wick, and the surface energy gradient between the superhydrophobic structure of the secondary wick and the superhydrophilic structure of the primary wick 3, and circulates continuously in turn.

[0061] Compared with the prior art, traditional heat pipes mostly use a single working medium and do not optimize in coordination with the wick structure, resulting in a limited selection range of working media and being unable to adapt to diverse heat dissipation scenarios. By introducing multiple types of working medium options and combining superhydrophilic-superhydrophobic composite wick structures, this application can flexibly adjust the type of working medium according to the heat generation power, operating temperature, and space limitation of the device, realizing the dynamic adaptation of the physical properties of the working medium and the capillary structure.

[0062] Through the above technical solutions, this application effectively solves the problem of the decrease in the heat transfer limit caused by insufficient working medium reflux in the ultra-thin heat pipe. By matching the surface tension, viscosity, and phase change characteristics of different working media, the liquid reflux efficiency driven by capillary pressure is enhanced, and at the same time, the droplet shedding speed in the condensation zone 5 is optimized, thereby improving the overall heat dissipation performance while maintaining the ultra-thin structure.

[0063] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0064] The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. An ultra-thin vapor chamber based on a bionic capillary wick, characterized in that, including a lower cover plate (2) which is provided with a cavity filled with a liquid working medium; a primary wick (3) laid on the inner bottom surface of the cavity; a bionic secondary wick (4) laid on the top surface of the primary wick (3); an upper cover plate (1) connected to the top of the lower cover plate (2) to seal the primary wick (3) and the bionic secondary wick (4) in the cavity of the lower cover plate (2); the primary wick (3) and the bionic secondary wick (4) are of the same or different porous medium structures; the ultra-thin vapor chamber is sequentially divided into an evaporation zone (7), a heat insulation zone (6) and a condensation zone (5) along its length direction.

2. The ultra-thin vapor chamber based on a bionic wick according to claim 1, wherein the bionic secondary wick (4) includes 2-15 bionic capillary wicks (41) arranged at equal intervals along the width direction of the ultra-thin vapor chamber.

3. The ultra-thin vapor chamber based on a bionic wick according to claim 2, characterized in that, the width of the bionic capillary wick (41) gradually and smoothly widens from the condensation zone (5) to the evaporation zone (7), presenting an isosceles trapezoid structure.

4. The ultra-thin vapor chamber based on a bionic wick according to claim 2, wherein, the porous surface of the primary wick (3) located in the evaporation zone (7) has a super-hydrophilic micro-nano structure, the porous surface of the primary wick (3) located in the heat insulation zone (6) close to the evaporation zone (7) has a super-hydrophilic micro-nano structure, the lower porous surface of the primary wick (3) located in the condensation zone (5) has a super-hydrophilic micro-nano structure, the lower porous surface of the primary wick (3) located in the heat insulation zone (6) close to the condensation zone (5) has a super-hydrophilic micro-nano structure, the upper porous surface of the primary wick (3) located in the condensation zone (5) has a super-hydrophobic micro-nano structure, and the upper porous surface of the primary wick (3) located in the heat insulation zone (6) close to the condensation zone (5) has a super-hydrophobic micro-nano structure.

5. The ultra-thin vapor chamber based on a bionic wick according to claim 4, wherein the bionic capillary wick (41) has a triangular serrated structure (42) with left and right intervals on both sides above the super-hydrophobic micro-nano structure of the primary wick (3).

6. The ultra-thin vapor chamber based on a bionic wick according to claim 1 or 4, characterized in that, the porous surface of the bionic secondary wick (4) has a super-hydrophilic micro-nano structure.

7. The ultra-thin vapor chamber based on a bionic wick according to claim 1, wherein, the material of the primary wick (3) and / or the bionic secondary wick (4) includes one or more of sintered copper powder, wire mesh, and copper foam.

8. The ultra-thin vapor chamber based on a bionic wick according to claim 1, wherein the upper cover plate (1) and the lower cover plate (2) are made of the same material, both of which are metal materials.

9. The ultra-thin vapor chamber based on a bionic wick according to claim 8, characterized in that, the upper cover plate (1) and the lower cover plate (2) are made of copper, aluminum, or stainless steel.

10. The ultra-thin vapor chamber based on a bionic wick according to claim 1, wherein the liquid working medium is one of water, acetone, alcohols, and aqueous alcohol solutions.

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