An ultrathin heat spreader, its preparation method and electronic equipment

Abstract

This invention belongs to the technical field of phase change heat transfer, and discloses an ultrathin vapor chamber, its preparation method, and electronic equipment. The ultrathin vapor chamber includes: a first receiving groove on one side of an upper cover plate and a second receiving groove on one side of a lower cover plate; multiple first cylinders arrayed in a first region inside the first receiving groove; and vapor-liquid coplanar wicking cores located corresponding to the first cylinders inside the second receiving groove; corresponding upper and lower support column structures located in a second region inside the first and second receiving grooves; and multiple gap regions within the support column structures, each gap region containing a vapor-liquid coplanar wicking core. This invention comprehensively utilizes both vapor-liquid coplanar and vapor-liquid coplanar structures. The larger contact area of ​​the vapor-liquid coplanar structure reduces the phase change heat transfer thermal resistance, while the vapor-liquid coplanar structure reduces the vapor flow resistance in the adiabatic section, which is beneficial for improving the heat dissipation capacity of the ultrathin vapor chamber with extremely small internal cavity thickness.

Description

Technical Field

[0001] This invention belongs to the technical field of phase change heat transfer, and more specifically, relates to an ultrathin heat spreader, its preparation method, and electronic equipment. Background Technology

[0002] The trend towards high performance, miniaturization, and integration in portable electronic devices has led to a rapid increase in heat flux density within confined spaces. This significantly increases the operating temperature of these devices, limiting their performance, shortening their lifespan, increasing the probability of failure, and reducing user satisfaction. Therefore, achieving efficient heat dissipation within portable electronic devices is of paramount importance.

[0003] Ultrathin vapor chambers, generally referring to those with a thickness of less than 2mm, are widely used in portable electronic devices such as smartphones and tablets due to their high heat transfer efficiency and stability. With the development of 5G communication technology and the continuous upgrading of electronic devices, while improving performance, the thickness of these devices has also decreased. This has led to a significant reduction in the installation space for heat dissipation equipment, resulting in a substantial increase in the performance requirements for such equipment. Consequently, the demand for developing high-performance ultrathin vapor chambers with a total thickness of less than 0.3mm is constantly growing.

[0004] The total thickness of a vapor chamber can be reduced by decreasing the thickness of the shell, wick, and vapor chamber. However, as the thickness of the vapor chamber and wick of the vapor chamber decreases, the vapor flow resistance within the ultrathin vapor chamber increases significantly, and the capillary force of the wick decreases, both of which deteriorate the heat transfer performance of the vapor chamber, making it difficult to meet the heat dissipation requirements of miniaturized electronic devices.

[0005] Therefore, how to design an ultrathin heat exchange plate with low total thickness and high heat transfer performance has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides an ultrathin heat exchange plate, its preparation method and electronic device, to solve the problem of poor heat transfer performance of the existing ultrathin heat exchange plates.

[0007] To achieve the above objectives, according to a first aspect of the present invention, an ultrathin heat spreader is provided, comprising an upper cover plate, a lower cover plate, and a working fluid. A first receiving groove is provided on one side of the upper cover plate, and a second receiving groove is provided on one side of the lower cover plate. The upper cover plate and the lower cover plate are sealed together such that the first receiving groove and the second receiving groove are joined together to form a sealed cavity, and the sealed cavity is filled with the working fluid.

[0008] The sealed cavity includes a first region and a second region in the length direction. The first receiving groove has a plurality of first cylinders arranged in an array in the first region. The second receiving groove has a vapor-liquid eccentric type liquid suction core at the location corresponding to the area where the first cylinders are arranged.

[0009] Both the first and second receiving tanks have support column structures in the second region, with the support column structures inside the first and second receiving tanks corresponding vertically. Each support column structure has multiple gap regions, and each of the first and second receiving tanks has a vapor-liquid coplanar suction core in any of these gap regions.

[0010] According to the ultrathin heat spreader provided by the present invention, the support column structure includes multiple rows of strip columns along the width direction of the sealed cavity, each row of strip columns is formed by multiple strip columns arranged together, and multiple gap regions are provided between the multiple rows of strip columns.

[0011] According to the ultrathin heat spreader provided by the present invention, the support column structure includes multiple combined column groups along the width direction of the sealed cavity, each combined column group includes at least one row of strip columns, the gap between two adjacent combined column groups forms the gap region, the width of multiple gap regions is the same, and when the combined column group includes multiple rows of strip columns, the spacing between two adjacent rows of strip columns is the same.

[0012] And / or, the ratio of the total width of the plurality of said gap regions to the width of the sealed cavity is 40-60%; the number of said gap regions is 3-5.

[0013] According to the ultra-thin heat spreader provided by the present invention, when the combined column group includes multiple rows of the strip columns, adjacent rows of the strip columns are staggered.

[0014] And / or, the support column structure includes a row of strip columns in each of the two combined column groups located on both sides in the width direction.

[0015] According to the ultrathin heat spreader provided by the present invention, the second region is located at the middle part of the sealed cavity along the length direction, and the regions on both sides of the second region along the length direction are respectively designated as the first region.

[0016] According to the ultrathin heat spreader provided by the present invention, the vapor-liquid coplanar liquid absorption core disposed in any of the gap regions inside the second receiving tank is a micro-column array.

[0017] According to a second aspect of the present invention, a method for preparing an ultrathin heat exchanger plate is provided, for preparing the ultrathin heat exchanger plate described in any of the above claims, wherein the vapor-liquid coplanar liquid-absorbing core disposed in any of the gap regions inside the second receiving groove of the ultrathin heat exchanger plate is a micro-pillar array, and the preparation method includes:

[0018] The first receiving groove, the first cylinder, and the support column structure are etched on the upper cover plate, and the second receiving groove, the micro-column array, and the support column structure are etched on the lower cover plate.

[0019] The lower cover plate and the liquid suction core material after etching the pillar structure are cleaned respectively, wherein the liquid suction core material includes a vapor-liquid antagonistic liquid suction core and a vapor-liquid coplanar liquid suction core;

[0020] The cleaned liquid-absorbing core material is sintered onto the cleaned lower cover plate, wherein the vapor-liquid eccentric liquid-absorbing core is sintered on the inner wall of the lower cover plate, and the vapor-liquid coplanar liquid-absorbing core is sintered on the micropillar array.

[0021] The lower cover plate is cleaned again after the sintering of the liquid-absorbing core material, and then micro-nano structures are prepared on the liquid-absorbing core material by etching, followed by rinsing with water.

[0022] The upper cover plate and the lower cover plate are sealed together to form a shell, and an injection pipe is connected to one end of the shell. The working fluid is then injected into the shell through the injection pipe, and the shell is sealed to obtain the ultrathin heat spreader.

[0023] The method for preparing an ultrathin heat spreader according to the present invention further includes, after preparing the micro / nano structure and before sealing and connecting the upper cover plate and the lower cover plate:

[0024] The upper cover plate after etching the pillar structure and the lower cover plate after fabricating the micro / nano structure are respectively subjected to acid washing operations.

[0025] According to the method for preparing the ultrathin heat spreader provided by the present invention, injecting the working fluid into the shell and performing a sealing operation specifically includes:

[0026] Pure water is boiled continuously for a preset time to obtain the working fluid, which is then injected into the sealed cavity.

[0027] The shell after being injected with the working fluid is immersed in liquid nitrogen, and the sealed cavity is evacuated. Then, the injection tube is sealed with clamps to complete one degassing operation.

[0028] After the shell has been degassed once, it is immersed in boiling water for a preset time to perform a second degassed process. Then, the injection tube is sealed a second time to complete the sealing of the injection tube.

[0029] According to a third aspect of the present invention, an electronic device is provided, comprising an ultrathin heat spreader as described in any of the preceding claims, and further comprising a working module, wherein the ultrathin heat spreader is used to dissipate heat from the working module.

[0030] In summary, compared with the prior art, the ultrathin heat spreader, its preparation method, and electronic equipment provided by the present invention offer the following advantages:

[0031] 1. A first cylindrical and support column structure is set inside the sealed cavity to provide support and form a vapor flow channel. The liquid wick is used to condense the liquid working fluid and serves as a flow channel for the liquid working fluid. The gaps on the liquid wick can provide capillary force to promote the flow of the liquid working fluid. Furthermore, the combination of vapor-liquid non-planar structure and vapor-liquid coplanar structure is used. The larger contact area of ​​the vapor-liquid non-planar liquid wick reduces the phase change heat transfer thermal resistance, while the vapor-liquid coplanar liquid wick reduces the vapor flow resistance of the adiabatic section and the vapor heat transfer thermal resistance. This is beneficial to improve the heat dissipation capacity of the ultra-thin heat spreader under extremely small inner cavity thickness, thereby further reducing the thickness of the heat spreader and improving the heat transfer performance of the ultra-thin heat spreader to meet the heat dissipation requirements of highly integrated ultra-thin electronic devices.

[0032] 2. The support column structure is designed as a strip column structure, which helps to improve the support strength inside the sealed cavity while ensuring smooth steam flow and reducing steam flow resistance. This is beneficial to the overall structural stability of the heat spreader and ensures the normal use of the heat spreader.

[0033] 3. The vapor-liquid coplanar liquid suction core set in any gap area inside the second receiving tank is set as a micro-column array. By designing the size of the second cylinder that makes up the micro-column array, the second cylinder is also set as a vapor-liquid coplanar structure, which is beneficial to improve the support strength, while ensuring that the steam has a small flow resistance and heat transfer resistance, thereby improving the heat exchange performance of the heat spreader.

[0034] 4. The thickness of the provided ultra-thin heat spreader can be reduced to 0.25mm, which is much lower than that of the traditional vapor-liquid non-planar ultra-thin heat spreader. By combining the vapor-liquid non-planar liquid wick and the vapor-liquid coplanar liquid wick, an effective thermal conductivity of 6000~24000W / (m·K) can be achieved at extreme thicknesses. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the structure of the top cover plate provided by the present invention;

[0036] Figure 2 This is a schematic diagram of the structure of the lower cover plate without a liquid-absorbing core provided by the present invention;

[0037] Figure 3 This is a schematic diagram of the upper cover plate provided by the present invention;

[0038] Figure 4 This is a schematic diagram of the lower cover plate provided by the present invention before sintering to prepare the liquid-absorbing core;

[0039] Figure 5 This is a schematic diagram of the lower cover plate provided by the present invention after sintering to prepare the liquid-absorbing core;

[0040] Figure 6 This is a schematic diagram showing the specific dimensions of the support column structure provided by the present invention;

[0041] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0042] 1-Upper cover plate; 11-First receiving groove; 12-First cylinder; 13-Strip column; 14-Gap region; 21-First region; 22-Second region; 3-Lower cover plate; 31-Second receiving groove; 32-Micro column array; 33-Vacuum-liquid eccentric suction core; 34-Vacuum-liquid coplanar suction core; 4-Perforation region. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0044] Please see Figure 1 and Figure 2 This embodiment provides an ultrathin heat spreader, which includes an upper cover plate 1, a lower cover plate 3 and a working fluid. The upper cover plate 1 has a first receiving groove 11 on one side and the lower cover plate 3 has a second receiving groove 31 on one side. The upper cover plate 1 and the lower cover plate 3 are sealed together so that the first receiving groove 11 and the second receiving groove 31 are combined to form a sealed cavity, and the sealed cavity is filled with the working fluid.

[0045] The sealed cavity includes a first region 21 and a second region 22 in the length direction. The first receiving groove 11 has a plurality of first cylinders 12 arranged in the first region 21 inside. The second receiving groove 31 has a vapor-liquid eccentric type liquid suction core 33 at the location corresponding to the area where the first cylinders 12 are arranged.

[0046] The first receiving tank 11 and the second receiving tank 31 each have support column structures in the second region 22, and the support column structures inside the first receiving tank 11 and the second receiving tank 31 are vertically corresponding. Each support column structure has multiple gap regions 14, and each of the first receiving tank 11 and the second receiving tank 31 has a vapor-liquid coplanar suction core in any of these gap regions 14. The support column structure inside the first receiving tank 11 has multiple gap regions 14, and the support column structure inside the second receiving tank 31 also has multiple gap regions 14, and the gap regions 14 inside the first receiving tank 11 and the gap regions 14 inside the second receiving tank 31 are vertically corresponding.

[0047] During the use of the heat spreader, the lower cover plate 3 can contact the heat source. The initial sealed cavity is filled with liquid working fluid. The working fluid can be adsorbed in the liquid absorbent core, including the non-planar type and the coplanar type. After being heated, the working fluid evaporates into vapor. The vapor formed in the vapor-liquid non-planar type liquid absorbent core 33 flows upward to the region of the first cylinder 12, flows in the gap of the first cylinder 12 and flows along the gap of the support column structure. The liquid medium in the vapor-liquid non-planar type liquid absorbent core 33 decreases, so that the liquid medium in the vapor-liquid coplanar type liquid absorbent core 34 will flow to the vapor-liquid non-planar type liquid absorbent core 33; thereby, the heat source is cooled by the flow of the medium.

[0048] The first cylinder 12 and the support column structure provide support within the sealed cavity, thereby improving the structural stability of the heat exchange plate. The heat exchange plate contains both a vapor-liquid shunt core 33 with a large heat exchange area to reduce phase change heat transfer resistance, and a vapor-liquid coplanar shunt core 34 within the multiple gap regions 14 formed by the second support column structure to reduce steam flow resistance in the adiabatic section and further reduce steam heat transfer resistance. This combined approach enhances the heat transfer capacity of the ultra-thin heat exchange plate, achieving a reduction in heat exchange plate thickness while simultaneously increasing heat transfer efficiency.

[0049] Furthermore, the vapor-liquid coplanar suction core 34 disposed within any of the gap regions 14 inside the second receiving groove 31 is a micropillar array 32. The micropillar array 32 is formed by arranging second cylindrical arrays, where the diameter of the first cylinder 12 is larger than the diameter of the second cylinder. The plurality of second cylinders arranged in any of the gap regions 14 also form a vapor-liquid coplanar structure. (Reference) Figure 2In this embodiment, the size of the second cylinder is designed to be small. Multiple second cylinders arranged in an array in any gap region 14 form a micro-pillar array 32. The gaps between the micro-pillar array 32 are small, which can provide capillary force to promote the flow of liquid working fluid. Thus, the micro-pillar array 32 is used for the flow of liquid working fluid. The support column structure located on the same plane as the micro-pillar array 32 is used for steam flow. The micro-pillar array 32 forms a vapor-liquid coplanar structure, that is, the micro-pillar array 32 also serves as a vapor-liquid coplanar liquid absorbing core 34, which is beneficial to reduce steam flow resistance and improve heat transfer capacity.

[0050] In some specific embodiments, reference is made to Figure 1 and Figure 2 The support column structure includes multiple rows of strip columns 13 along the width direction of the sealed cavity. Each row of strip columns 13 is formed by arranging multiple strip columns 13, and multiple gap regions 14 are provided between the multiple rows of strip columns 13. The strip column 13 is a column that is long and narrow in the length direction.

[0051] Specifically, the support column structure includes multiple combined column groups along the width direction of the sealed cavity. Each combined column group includes at least one row of strip columns 13. The gap between two adjacent combined column groups forms the gap region 14. The width of multiple gap regions 14 is the same. When the combined column group includes multiple rows of strip columns 13, the spacing between two adjacent rows of strip columns 13 is the same.

[0052] Specifically, the ratio of the total width of the plurality of gap regions 14 to the width of the sealed cavity is 40-60%; the number of gap regions 14 is 3-5. The vapor-liquid coplanar structure formed under these design parameters can better facilitate the flow of steam, reduce the steam flow resistance in the insulation section, reduce the steam heat transfer resistance, and ensure that the support column structure provides stable support for the cavity.

[0053] refer to Figure 1 and Figure 2 When the combined column group includes multiple rows of the strip columns 13, the adjacent rows of strip columns 13 are staggered; this helps to ensure the smooth flow of steam in the gaps between the strip columns 13 and avoids dead zones in the flow.

[0054] The support column structure comprises a row of strip columns 13 in each of the two combined column groups located on both sides in the width direction. Each row of strip columns 13 is positioned with a gap region 14 between adjacent columns. This arrangement helps ensure the support strength of the support column structure at the edges and allows the support column structure to be positioned as close to the center as possible, facilitating smooth steam flow and improving heat exchange capacity.

[0055] refer to Figure 1 and Figure 2 In this embodiment, the second region 22 is located in the middle part of the sealed cavity along its length, and the regions on both sides of the second region 22 along its length are respectively designated as the first region 21. The first region 21 on one side is a heat exchange evaporation section, the second region 22 in the middle is an insulation section, and the first region 21 on the other side is a condensation section, which can better realize the circulation of the medium to achieve heat source heat dissipation.

[0056] In practical use, the evaporation side of the lower cover plate 3 can contact the heat source. The initial sealed cavity is filled with liquid working fluid, which can be adsorbed into the wicking core. The working fluid on the evaporation side evaporates into vapor when heated. Under the action of pressure difference, it flows sequentially through the first cylinder 12 on the evaporation side, the support column structure, and the first cylinder 12 on the condensation side. It condenses into liquid in the condensation section. The liquid working fluid is adsorbed by the vapor-liquid wicking core on the condensation side and then flows back to the wicking cores in the insulation section and the evaporation section, working in a cycle. The heat spreader utilizes the phase change and flow of the working fluid to dissipate heat from the heat source.

[0057] Furthermore, micro- and nano-structures are respectively provided on the vapor-liquid non-planar suction core 33 and the vapor-liquid coplanar suction core 34. The vapor-liquid non-planar suction core 33 can be sintered onto the inner wall of the lower cover plate 3; the vapor-liquid coplanar suction core 34 can be sintered onto the second cylindrical array. The vapor-liquid non-planar suction core 33 and the vapor-liquid coplanar suction core 34 disposed in any gap region 14 inside the first receiving groove 11 can both be copper meshes. That is, by sintering, the micro-pillars, i.e., the second cylinders, and the copper meshes are connected to form a vapor-liquid coplanar suction core, and at the same time, the copper meshes of the vapor-liquid non-planar suction cores are connected to the lower cover plate 3.

[0058] In some specific embodiments, the depth ratio of the first receiving groove 11 and the second receiving groove 31 is 1:2-2:1. The diameter of the first cylinder 12 is 0.6-1mm, and the center distance between two adjacent first cylinders 12 is 0.6-3mm. The diameter of the second cylinder is 0.08-0.12mm, and the center distance between two adjacent second cylinders is 0.2-0.4mm. The width of the strip column 13 in the width direction is 0.2-0.6mm; the length of the strip column 13 in the length direction is 1.2-7mm; the spacing between two adjacent rows of strip columns 13 in the combined column group is 1-2mm; the spacing between two adjacent strip columns 13 in the same row is 0.4-1.2mm, such as... Figure 6 As shown. The heat spreader formed by the above-mentioned design dimensions has good supporting strength and good heat exchange performance.

[0059] This second embodiment provides a method for preparing an ultrathin heat exchanger plate, used to prepare the ultrathin heat exchanger plate described in any of the above embodiments. The vapor-liquid coplanar absorbing core disposed in any of the gap regions inside the second receiving groove of the ultrathin heat exchanger plate is a micro-pillar array. The preparation method includes:

[0060] The first receiving groove 11, the first cylinder 12, and the support column structure are etched onto the upper cover plate 1, and the second receiving groove 31, the micro-pillar array 32, and the support column structure are etched onto the lower cover plate 3. Figure 3 and Figure 4 As shown;

[0061] The lower cover plate 3 and the liquid suction core material after etching the pillar structure are cleaned respectively, wherein the liquid suction core material includes a vapor-liquid antagonistic liquid suction core 33 and a vapor-liquid coplanar liquid suction core 34.

[0062] The cleaned liquid-absorbing core material is sintered onto the cleaned lower cover plate 3, wherein the vapor-liquid eccentric liquid-absorbing core 33 is sintered on the inner wall of the lower cover plate 3, and the vapor-liquid coplanar liquid-absorbing core 34 is sintered onto the micropillar array 32, as shown below. Figure 5 As shown;

[0063] The lower cover plate 3 is cleaned again after the sintering of the liquid-absorbing core material, and then micro-nano structures are prepared on the liquid-absorbing core material by etching, followed by rinsing with water.

[0064] The upper cover plate 1 and the lower cover plate 3 are sealed together to form a shell, and an injection pipe is connected to one end of the shell. The working fluid is then injected into the shell through the injection pipe, and the shell is sealed to obtain the ultrathin heat spreader.

[0065] Further, the first receiving groove 11, the first cylinder 12, and the support column structure are etched and fabricated on the upper cover plate 1, and the second receiving groove 31, the micro-pillar array 32, and the support column structure are etched and fabricated on the lower cover plate 3. That is, after etching the column structures on the upper cover plate 1 and the lower cover plate 3 respectively, the process further includes:

[0066] A punching operation is performed on one end of the upper cover plate 1 and one end of the lower cover plate 3 to obtain a punching area 4. A certain shape is formed in the punching area 4. After punching, there are two different sizes of openings on the surface of the shell plate. The punching area 4 at the end of the upper cover plate 1 is connected to the first receiving groove 11, and the punching area 4 at the end of the lower cover plate 3 is connected to the second receiving groove 31, which is used to connect the injection pipe and form an injection channel.

[0067] Furthermore, after fabricating the micro / nano structure and before sealing the upper cover plate 1 and the lower cover plate 3, the process also includes:

[0068] The upper cover plate 1 after etching the column structure and the lower cover plate 3 after preparing the micro-nano structure are respectively subjected to acid washing operations.

[0069] Furthermore, injecting the working fluid into the housing and performing a sealing operation specifically includes:

[0070] Pure water is boiled continuously for a preset time to obtain the working fluid, which is then injected into the sealed cavity.

[0071] The shell after being injected with the working fluid is immersed in liquid nitrogen, and the sealed cavity is evacuated. Then, the injection tube is sealed with clamps to complete one degassing operation.

[0072] After the shell has been degassed once, it is immersed in boiling water for a preset time to perform a second degassed operation. Then, the injection tube is sealed a second time to complete the sealing operation.

[0073] This third embodiment provides an electronic device, which includes the ultra-thin heat spreader described in any of the above embodiments, and also includes a working module. The ultra-thin heat spreader is used to dissipate heat from the working module. The electronic device can be a mobile phone, tablet, or other device that requires a heat dissipation module, which includes the ultra-thin heat spreader.

[0074] The core of this embodiment lies in providing an ultra-thin heat spreader with a total thickness of less than 0.3 mm and excellent heat transfer performance, which can meet the heat dissipation requirements of high-performance miniaturized electronic devices. In some specific embodiments, such as Figures 1-6 As shown, the ultrathin heat spreader includes an upper cover plate 1, a lower cover plate 3, and a working fluid. The upper cover plate 1 and the lower cover plate 3 are sealed together to form a cavity containing the working fluid. The upper cover plate 1 includes an upper shell plate, a support column structure, and a first cylinder 12. The lower cover plate 3 includes a lower shell plate, a support column structure, and a liquid-absorbing core. The support column structure and the first cylinder 12 provide support and a vapor flow channel. The liquid-absorbing core includes a vapor-liquid non-planar liquid-absorbing core 33, a vapor-liquid coplanar liquid-absorbing core 34, and a vapor-liquid coplanar structure formed by a micro-column array 32. The vapor-liquid non-planar liquid-absorbing core 33 is a copper mesh, and the vapor-liquid coplanar structure is a combination of a copper mesh and micro-columns.

[0075] The specific preparation steps are as follows: A copper plate made of C19400 material is etched. The etching depth of a 0.1mm thick copper plate is 0.05mm, resulting in an upper shell plate, a support pillar structure, and a first cylinder 12. A copper plate with a thickness of 0.15mm is etched to a depth of 0.1mm, resulting in a lower shell plate, a support pillar structure, and a micro-pillar array 32, i.e., a second cylinder. The diameter of the first cylinder 12 is 0.6mm, and the center distance between adjacent first cylinders 12 is 1.2mm. The diameter of the micro-pillars, i.e., the second cylinders, is 0.1mm, and the center distance between adjacent micro-pillars is 0.325mm. The width of the strip pillars 13 is 0.4mm. The row spacing between two adjacent rows of strip pillars 13 within the same combination pillar group is 1.2mm, and the distance between adjacent strip pillars 13 in the same row is 0.6mm.

[0076] The copper mesh and the lower cover plate 3 without copper mesh were cleaned sequentially with ethyl acetate, anhydrous ethanol, 5% dilute sulfuric acid solution, and deionized water, and then dried. Ultrasonic cleaning is preferred. The copper mesh and the lower cover plate 3 without copper mesh were clamped together using a graphite mold and placed in the quartz tube of a vacuum sintering furnace. High-temperature composite sintering was performed using a gradient heating method. First, the temperature was preheated to 40°C at a rate of 2°C / min. Then, the temperature was increased from 40°C to 300°C over 55 minutes, and then further increased to 600°C at a rate of 300°C / h, and held for 90 minutes.

[0077] Micro-nano structures for promoting the reflux of the liquid working fluid were etched onto the liquid wick. After 3D copper wires were vacuum sintered onto the lower cover plate 3 to form a composite structure, the sintered lower cover plate 3 was sequentially cleaned with ethyl acetate, anhydrous ethanol, a 5% (w / w) dilute sulfuric acid solution, and deionized water. Specifically, the cleaning process involved cleaning with ethyl acetate and ethanol, followed by immersion in a 5% (w / w) dilute sulfuric acid solution to remove surface grease, oxides, and other contaminants. The plate was then rinsed with pure water and dried. After drying, it was placed in an alkaline etching solution and etched under a water bath heating environment. Immediately after etching, the surface was rinsed with plenty of pure water.

[0078] The upper and lower cover plates are subjected to acid pickling. The upper and lower cover plates are ultrasonically cleaned in dilute sulfuric acid with a mass fraction of 5%, and then cleaned with deionized water and anhydrous ethanol to make the surface structure composition Cu.

[0079] After the upper and lower cover plates are aligned and fixed, they are welded along a set path to obtain an ultra-thin heat spreader shell that is sealed on all sides and retains only the punched area 4. Then, a liquid injection pipe is installed in the punched area 4 using high-frequency welding to obtain the main body of the ultra-thin heat spreader.

[0080] A two-stage degassing preparation method is employed, involving boiling pure water continuously for over two hours, followed by injecting a certain amount of working fluid into the ultrathin vapor chamber using a precision syringe. After injection, the injection tube (which can be a copper tube) is connected to the external connector of the molecular pump assembly. The chamber is then immersed in liquid nitrogen, and the vacuum pump and molecular pump are sequentially activated. When the pressure of the molecular pump assembly displays 1×10⁻⁶... - 3 When the pressure is below hPa, the copper tube is sealed with clamps to complete the first degassing. Then, the heating section of the shell is immersed in 100°C water for 90 seconds for a second degassing. A second seal is then performed 1 cm below the first seal position to isolate non-condensable gases. Finally, the shell is sealed by resistance welding.

[0081] This embodiment has the following advantages: the first cylinder 12 and the support column structure provide support and form a vapor flow channel; the wick is used to condense the liquid working fluid and serves as a flow channel for the liquid working fluid; the voids in the copper mesh, the gaps between the micropillars, and the micro-nano structures on the surface of the wick can provide capillary force, promoting the flow of the liquid working fluid. The larger contact area of ​​the vapor-liquid non-planar wick 33 reduces the phase change heat transfer thermal resistance, while the vapor-liquid coplanar wick 34 reduces the vapor flow resistance in the adiabatic section, thus reducing the vapor heat transfer thermal resistance and improving the heat dissipation capacity of the ultra-thin heat spreader with an extremely small inner cavity thickness. The total thickness is only 0.25 mm, and it has excellent heat transfer performance, thus meeting the heat dissipation requirements of high-performance miniaturized electronic devices.

[0082] The wicking core, after etching and acid washing, exhibits excellent hydrophilicity. The voids within the copper mesh, the gaps between the micropillars, and the micro-nano structures on the surface of the wicking core provide capillary force, promoting the flow of the liquid working fluid. In this embodiment, the total thickness of the ultrathin vapor chamber is only 0.25 mm, far less than that of traditional vapor-liquid non-planar ultrathin vapor chambers. By combining the vapor-liquid non-planar wicking core 33 and the vapor-liquid coplanar wicking core 34, and using water as the working fluid, an effective thermal conductivity of 6000–24000 W / (m·K) can be maintained even at an extreme thickness of 0.25 mm.

[0083] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An ultrathin heat spreader, characterized in that, It includes an upper cover plate, a lower cover plate, and a working fluid. The upper cover plate has a first receiving groove on one side, and the lower cover plate has a second receiving groove on one side. The upper cover plate and the lower cover plate are sealed together so that the first receiving groove and the second receiving groove are combined to form a sealed cavity, and the sealed cavity is filled with the working fluid. The sealed cavity includes a first region and a second region in the length direction. The first receiving groove has a plurality of first cylinders arranged in an array in the first region. The second receiving groove has a vapor-liquid eccentric type liquid suction core at the location corresponding to the area where the first cylinders are arranged. The first and second receiving tanks are respectively provided with support column structures in the second region, and the support column structures inside the first and second receiving tanks are vertically corresponding; the support column structure is provided with multiple gap regions, and the first and second receiving tanks are respectively provided with a vapor-liquid coplanar liquid suction core in any of the gap regions. The second region is located in the middle part of the sealed cavity along the length direction, and the regions on both sides of the second region along the length direction are respectively designated as the first region; the first region on one side of the second region is a heat exchange evaporation section, the second region in the middle is an insulation section, and the first region on the other side of the second region is a condensation section. The vapor-liquid coplanar suction core disposed in any of the gap regions inside the second receiving tank is a micro-pillar array; the vapor-liquid coplanar suction core disposed in any of the gap regions inside the first receiving tank is a copper mesh.

2. The ultrathin heat spreader as described in claim 1, characterized in that, The support column structure includes multiple rows of strip columns along the width direction of the sealed cavity. Each row of strip columns is formed by arranging multiple strip columns, and multiple gap areas are provided between the multiple rows of strip columns.

3. The ultrathin heat spreader as described in claim 2, characterized in that, The support column structure includes multiple combined column groups along the width direction of the sealed cavity. Each combined column group includes at least one row of strip columns. The gap between two adjacent combined column groups forms the gap region. The width of multiple gap regions is the same. When the combined column group includes multiple rows of strip columns, the spacing between two adjacent rows of strip columns is the same. And / or, the ratio of the total width of the plurality of said gap regions to the width of the sealed cavity is 40-60%; the number of said gap regions is 3-5.

4. The ultrathin heat spreader as described in claim 3, characterized in that, When the combined column group includes multiple rows of the strip columns, adjacent rows of the strip columns are staggered. And / or, the support column structure includes a row of strip columns in each of the two combined column groups located on both sides in the width direction.

5. A method for preparing an ultrathin heat spreader, characterized in that, The method for preparing an ultrathin heat exchanger plate according to any one of claims 1-4, wherein the vapor-liquid coplanar liquid-absorbing core disposed in any of the gap regions inside the second receiving groove of the ultrathin heat exchanger plate is a micro-pillar array, the preparation method comprising: The first receiving groove, the first cylinder, and the support column structure are etched on the upper cover plate, and the second receiving groove, the micro-column array, and the support column structure are etched on the lower cover plate. The lower cover plate and the liquid suction core material after etching the pillar structure are cleaned respectively, wherein the liquid suction core material includes a vapor-liquid antagonistic liquid suction core and a vapor-liquid coplanar liquid suction core; The cleaned liquid-absorbing core material is sintered onto the cleaned lower cover plate, wherein the vapor-liquid eccentric liquid-absorbing core is sintered on the inner wall of the lower cover plate, and the vapor-liquid coplanar liquid-absorbing core is sintered on the micropillar array. The lower cover plate is cleaned again after the sintering of the liquid-absorbing core material, and then micro-nano structures are prepared on the liquid-absorbing core material by etching, followed by rinsing with water. The upper cover plate and the lower cover plate are sealed together to form a shell, and an injection pipe is connected to one end of the shell. The working fluid is then injected into the shell through the injection pipe, and the shell is sealed to obtain the ultrathin heat spreader.

6. The method for preparing the ultrathin heat spreader as described in claim 5, characterized in that, The process includes, after fabricating the micro / nano structure and before sealing the upper cover plate and the lower cover plate together: The upper cover plate after etching the pillar structure and the lower cover plate after fabricating the micro / nano structure are respectively subjected to acid washing operations.

7. The method for preparing the ultrathin heat spreader as described in claim 5, characterized in that, The process of injecting the working fluid into the housing and then sealing it specifically includes: Pure water is boiled continuously for a preset time to obtain the working fluid, which is then injected into the sealed cavity. The shell after being injected with the working fluid is immersed in liquid nitrogen, and the sealed cavity is evacuated. Then, the injection tube is sealed with clamps to complete one degassing operation. After the shell has been degassed once, it is immersed in boiling water for a preset time to perform a second degassed process. Then, the injection tube is sealed a second time to complete the sealing of the injection tube.

8. An electronic device, characterized in that, The device includes the ultra-thin heat spreader as described in any one of claims 1-4, and further includes a working module, wherein the ultra-thin heat spreader is used to dissipate heat from the working module.

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