Composite wick, vapor chamber and heat pipe

Abstract

The invention relates to the field of heat exchange and heat conduction, in particular to a composite wick, a vapor chamber and a heat pipe. Comprising a first material layer which is provided with a first surface and a second surface, the first surface and the second surface are respectively provided with a diversion trench, and the diversion trench on the first surface and the heat conduction element shell jointly define a capillary channel; the second material layer is attached to the second surface of the first material layer, and capillary channels are defined by the second material layer and the flow guide grooves in the second surface of the first material layer. The first material layer and the second material layer of the wick and the shell define the capillary channel, the open flow guide grooves in the first material layer form the capillary channel, the flow speed and flow of working medium backflow are increased, and then the heat transfer capacity is improved. The characteristics of high capillary pressure and large flow can be achieved at the same time by regulating and controlling the size of the capillary channel of the first material layer and the size of the steam through hole of the second material layer of the wick.

Description

Technical Field

[0001] The present invention relates to the field of heat exchange and heat conduction, in particular to a composite liquid wick, a temperature averaging plate and a heat pipe. Background Art

[0002] Fluid phase change heat conduction is a commonly used heat conduction method in engineering applications. Heat pipes and vapor chambers are commonly used heat conduction elements based on fluid phase change. Such heat conduction elements include a shell, a wick, and a phase change heat transfer medium. A cavity is formed inside the shell, and the wick and phase change heat transfer medium are located inside the cavity. When the heat pipe and vapor chamber are in use, the outer side of the shell contacts the heat source. This area is called the heat source area, and a heat dissipation area is provided outside the heat source area. The wick has a variety of structures such as wire mesh, sintered copper powder, microcolumn array, grooves, foam metal, etc., has capillary properties, and can adsorb phase change heat transfer mediums.

[0003] When the heat pipe and vapor chamber operate, the phase-change heat transfer medium in the heat source region evaporates upon heating. The vapor then overflows the wick and flows into the steam chamber of the housing. After leaving the heat source region, the vapor condenses, releasing heat, then changes phase back to liquid. Capillary action within the wick allows the vapor to flow back to the heat source region. This cyclical process of evaporation and condensation transfers some of the heat from the heat source region to the heat sink region, reducing the temperature difference between the two regions and achieving both thermal conductivity and temperature uniformity.

[0004] In the prior art, the capillary pressure of wicks is limited or uncontrollable, restricting the working length and thermal conductivity of heat pipes and heat spreaders. This is particularly true under conditions of acceleration, where limited capillary pressure leads to a sharp drop in thermal conductivity or even cessation of operation. For example, wicks with commonly used wire mesh and foam structures have limited capillary capacity or high resistance to liquid flow. Wickers with grooved or similar structures have open fluid channels, resulting in poor capillary capacity, slowing the flow of the working fluid and reducing capillary flow, which in turn reduces the thermal conductivity of the heat spreader. The applicant's patent publication, CN117190762A, discloses a wick, its preparation method, and a heat spreader. The patent publication discloses a wick with a flow guide groove. The groove structure on one side of the wick and the shell of the heat spreader form a capillary channel for the return of the phase-change heat transfer medium. The other surface of the wick is open, forming a steam chamber. This capillary material offers significant improvements over previous groove structures, but the capillary force of the open-surface groove structure is still relatively weak. The purpose of this invention is to further improve the capillary structure and demonstrate application methods and cases. Summary of the Invention

[0005] In a first aspect, embodiments of the present application provide a composite absorbent core that can effectively increase capillary flow and improve thermal conductivity.

[0006] The composite liquid wick is installed in the heat-conducting element housing and includes: A first material layer having a first surface and a second surface, wherein the first surface and the second surface respectively have guide grooves, and the guide grooves on the first surface and the heat-conducting element housing together form a capillary channel; a second material layer adhered to the second surface of the first material layer and forming a capillary channel together with the guide groove on the second surface of the first material layer; The capillary tube is used to connect the heat source area and the heat dissipation area, so that the phase change heat transfer medium condensed in the heat dissipation area can flow back to the heat source area through the capillary tube under the action of capillary pressure.

[0007] In the embodiment of the present invention, the first and second material layers of the wick, along with the housing, form capillary channels. The open flow channels in the first material layer are then converted into capillary channels, significantly increasing the flow rate and velocity of the working fluid return flow, thereby improving heat transfer capacity. By manipulating the size of the capillary channels in the first material layer of the wick and the size of the steam pores in the second material layer, high capillary pressure and high flow rates can be achieved simultaneously. This overcomes the randomness and difficulty in controlling capillary pressure and working fluid flow in conventional solutions.

[0008] In a possible implementation, the first material layer is a capillary material layer, the second material layer is a dielectric material layer or a capillary material layer, and the dielectric material layer includes a solid dielectric material layer and a porous dielectric material layer.

[0009] In one possible implementation, a steam chamber is provided in the heat conducting element shell, the second material layer is provided on one side of the steam chamber, the first material layer is provided between the heat conducting element shell and the second material layer, and a capillary through hole is provided on the capillary channel of the first material layer. The capillary through hole is used to connect the capillary channel so that the phase change heat transfer medium and its steam can flow between the capillary channels of the first material layer.

[0010] In a possible implementation, the second material layer further has a steam through hole, which is used to connect the capillary tube and the steam chamber, so that the phase change heat transfer medium and its steam can flow between the capillary tube of the first material layer and the steam chamber.

[0011] In one possible implementation, the first ends of the first material layer and the second material layer are used to be placed in the heat source area, and the second ends of the first material layer and the second material layer are used to be placed in the heat dissipation area; so that the phase change heat transfer medium condensed in the heat dissipation area can flow back to the heat source area through the capillary channel of the first material layer under the action of capillary pressure.

[0012] In one possible implementation, the effective capillary radius of the steam pores at the first end of the second material layer is smaller than the effective capillary radius of the steam pores at the second end of the second material layer, so as to increase the capillary pressure causing the phase change heat transfer medium to flow back to the heat source area.

[0013] In a second aspect, an embodiment of the present application further provides a temperature vapor chamber.

[0014] The temperature equalizing plate includes the liquid wick in the first aspect and the shell; the shell has the cover plate, one side of the cover plate is used to contact the heat source, and the other side of the cover plate and the first material layer together form the capillary channel.

[0015] In one possible implementation, the shell has a steam chamber, the second material layer is arranged on one side of the steam chamber, and the first material layer is arranged between the heat-conducting element shell and the second material layer; a capillary through-hole is provided on the capillary tube of the first material layer, which is used to connect the capillary tube on the first capillary, so that the phase-change heat transfer medium and its steam can flow between the capillary tube of the first material layer; a steam through-hole is provided on the second material layer, and the steam through-hole is used to connect the capillary tube of the first material layer and the steam chamber, so that the phase-change heat transfer medium and its steam can flow between the capillary tube of the first material layer and the steam chamber.

[0016] In a third aspect, an embodiment of the present application further provides a heat pipe.

[0017] The heat pipe includes the liquid wick described in the first aspect and the shell; one side of the shell is used to contact the heat source, and the other side of the shell and the first material layer together form a capillary channel of the first material layer.

[0018] In one possible implementation, the shell has a steam chamber, the second material layer is arranged on one side of the steam chamber, and the first material layer is arranged between the heat-conducting element shell and the second material layer; a capillary through-hole is provided on the capillary tube of the first material layer, which is used to connect the capillary tube on the first capillary, so that the phase-change heat transfer medium and its steam can flow between the capillary tube of the first material layer; a steam through-hole is provided on the second material layer, and the steam through-hole is used to connect the capillary tube of the first material layer and the steam chamber, so that the phase-change heat transfer medium and its steam can flow between the capillary tube of the first material layer and the steam chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the connection between the wick and the housing according to an embodiment of the present invention; Figure 2 Schematic cross-sectional view of the connection between the absorbent core and the housing according to an embodiment of the present invention; Figure 3 is another schematic diagram of the connection relationship between the liquid absorbent core and the housing according to an embodiment of the present invention; Figure 4 2 is another cross-sectional schematic diagram of the connection relationship between the liquid absorbent core and the housing according to an embodiment of the present invention; Figure 5 Schematic diagram of the shape and arrangement of the vapor through holes in the second material layer of the absorbent core according to an embodiment of the present invention; Figure 6 Schematic diagram of theoretical results of capillary performance of a wick according to an embodiment of the present invention; Figure 7 Schematic diagram of the connection between the liquid wick and the housing of the temperature homogenizing plate according to an embodiment of the present invention; Figure 8 Schematic diagram of the exploded view of the vapor chamber according to an embodiment of the present invention; Figure 9 Schematic cross-sectional view of a temperature vapor chamber according to an embodiment of the present invention; Figure 10 Schematic diagram of the connection between the wick and the shell of the heat pipe according to an embodiment of the present invention; Figure 11 Schematic cross-sectional view of the connection between the wick and the shell of the heat pipe according to an embodiment of the present invention; Figure 12 is another cross-sectional schematic diagram of the connection relationship between the liquid wick and the shell of the heat pipe according to an embodiment of the present invention; Figure 13 is another cross-sectional schematic diagram of the connection relationship between the liquid wick and the shell of the heat pipe according to an embodiment of the present invention; Figure 14 Schematic diagram of an exploded view of a heat pipe according to an embodiment of the present invention; Figure 15 This is another schematic diagram of the decomposition of the heat pipe according to the embodiment of the present invention; Figure 16 is a schematic cross-sectional view of a flattened heat pipe according to an embodiment of the present invention; Figure 17 Schematic diagram of a method for preparing a liquid absorbent core according to an embodiment of the present invention; Figure 18 The capillary performance test data of the absorbent core of the embodiment of the present invention and the comparison with the commercial screen material are shown.

[0020] Explanation of the reference numerals: 10 - temperature averaging plate; 20 - heat pipe; 100 - shell; 101 - first cover plate; 102 - second cover plate; 103 - steam chamber; 104 - support member; 200 - wick; 201 - first material layer; 202 - second material layer; 210 - capillary channel; 220 - open capillary channel; 250 - capillary through hole; 251 - steam through hole; 400 - heat source area; 410 - insulation area; 420 - heat dissipation area. DETAILED DESCRIPTION

[0021] The following is a further detailed description of the present invention in conjunction with specific embodiments and accompanying drawings. Obviously, the embodiments described are only a portion of the embodiments, not all of the embodiments. Based on the following embodiments, all other embodiments proposed by ordinary technicians in this field without creative work are also within the scope of protection of the present invention.

[0022] The disclosure of the embodiments provides many different implementations or examples for implementing different schemes of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described in the embodiments. Of course, they are merely examples and are not intended to limit the present invention. In addition, reference numerals and / or reference letters may be repeated in different examples in the embodiments. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various implementations and / or settings discussed. In addition, if examples of various specific processes and materials are provided in the embodiments, those of ordinary skill in the art will appreciate the application of other processes and / or the use of other materials.

[0023] Reference Figure 1 and Figure 2 , and combined with Figure 8 and Figure 9 As shown, one embodiment of the present application provides a composite wick 200 for installation on the housing 100 of a heat spreader 10. The wick 200 is formed by combining a first material layer 201 and a second material layer 202. The first material layer 201 has a first surface and a second surface each having a flow guide groove. The flow guide groove, the heat spreader housing 100, and the second material layer 202 on the side adjacent to the steam chamber together form a closed capillary channel 210. The housing and the first material layer 201, as well as the first material layer 201 and the second material layer 202, can be fixedly connected by sintering (e.g., eutectic sintering) and welding.

[0024] The capillary channel 210 of the wick 200 is used to connect the heat source region 400 (also called the evaporation region) and the heat dissipation region 420 (also called the condensation region) so that the working fluid condensed in the heat dissipation region 420 can flow back to the heat source region 400 through the capillary channel 210 under the action of capillary pressure.

[0025] In this embodiment, the first material layer 201 is a capillary material layer, and the second material layer 202 is a dielectric material layer or a capillary material layer. The dielectric material layer includes a solid dielectric material layer and a porous dielectric material layer. The dielectric material layer is a thin film, such as a copper thin film.

[0026] Reference Figure 3 and Figure 4 , and combined with Figure 8 and Figure 9As shown, in the heat source region 400 (also known as the evaporation region) and the heat dissipation region 420 (also known as the condensation region), capillary holes 250 are provided in the first material layer 201, and steam holes 251 are provided in the second material layer 202. The capillary holes are used to connect to the capillary channel 210, allowing the working fluid and its vapor to flow between the capillary channels. The capillary holes 250 can be provided on the sidewalls of the capillary channel 210 and the wall near the steam chamber. The steam holes 251 are used to connect the capillary channel and the steam chamber, allowing the phase change heat transfer medium and its vapor to flow between the capillary channel of the first material layer and the steam chamber.

[0027] Figure 1 and Figure 2 The capillary structure described is mainly used for capillary flow in the insulation area 410. The insulation section is located between the evaporation section and the condensation section, and is used to maintain the integrity of the heat transfer path and reduce heat loss. Steam holes may not be arranged in this section, so the second material layer of the insulation section can be a solid film.

[0028] Figure 3 and Figure 4 The capillary structure described is mainly used in the heat source area 400 and the heat dissipation area 420. According to the application requirements, Figure 3 and Figure 4 The described capillary structure can also be used for the thermal insulation region 410 .

[0029] The cross-section of the capillary channel 210 of the first material layer of the wick 200 of this embodiment can be a variety of shapes such as semicircular, rectangular, trapezoidal, arcuate, major arcuate, minor arcuate, triangular, or a combination thereof, or shapes similar thereto. Those skilled in the art can make the selection according to actual needs. The width, spacing and height of the capillary channel 210 can vary from a few nanometers to several thousand microns. For example, the width of the capillary channel 210 can be 1 micron to 2000 microns, such as 50 microns, 100 microns, 200 microns, 500 microns, 1000 microns, etc.; the height of the capillary channel 210 can be 1 micron to 2000 microns, such as 5 microns, 10 microns, 20 microns, 50 microns, 100 microns, 200 microns, 500 microns, 1000 microns, etc.; the spacing of the capillary channel 210 can be 1 micron to 500 microns, such as 5 microns, 10 microns, 20 microns, 50 microns, 100 microns, etc.; the thickness of the material can vary from a few nanometers to several thousand microns. For example, the thickness of the material can be 0.01 micron to 200 microns, such as 1 micron, 5 microns, 10 microns, 20 microns, 50 microns, etc. The capillary channel can be a closed channel or a channel with capillary through holes. The capillary through holes can be shaped like a circle, a semicircle, an ellipse, a crescent, a triangle, a square, a rectangle, a trapezoid, a star, a bar, or a combination thereof. Irregular shapes are also possible. These capillary through holes can be arranged at the top of the capillary channel 210 or on the sidewall of the capillary channel 210. The size of the capillary through holes is controlled to be between 0.001 microns and 500 microns, such as 2 microns, 5 microns, 10 microns, 20 microns, 50 microns, etc.

[0030] In this embodiment, the second material layer 202 of the absorbent wick 200 can be a solid or porous film (vapor pores 251). The film thickness can range from a few nanometers to several thousand microns, for example, from 0.01 microns to 200 microns, such as 1 micron, 5 microns, 10 microns, 20 microns, 50 microns, 100 microns, etc. The shape of the vapor pores can be circular, semicircular, elliptical, crescent, triangular, square, rectangular, trapezoidal, star-shaped, strip-shaped, or a combination thereof. Irregular shapes are also possible. The size of the vapor pores is controlled to be between 0.001 microns and 500 microns. The shape, density, and arrangement of the vapor pores can be designed based on the required phase change and processing method. Figure 5 Schematic diagrams of several examples of film materials for the second material layer 202 of the absorbent core 200 of this embodiment are provided.

[0031] The second material layer can also be a porous medium or capillary material, such as a foam, wire mesh, sintered metal powder, or a combination thereof. The second material layer can also be made from the first material layer, with the first material layer superimposed on top of the second material layer. Based on this superposition principle, the second material layer can be formed by stacking multiple layers of materials according to application requirements. Each layer can use the same or different materials. Options include the first material layer, wire mesh, and film (the schematic diagram of this example is not shown).

[0032] The working principle of the liquid absorbent core 200 of this embodiment is as follows: Figures 1 to 5 As shown: The wick 200 is formed by combining a first material layer 201 and a second material layer 202. The guide grooves of the first material layer 201 are used to form a closed capillary channel 210 together with the inner wall of the housing 100 and the second material layer near the side of the steam chamber. The capillary channel 210 is a tubular structure with a defined direction. Compared with the prior art, in this embodiment, the working fluid flows along the closed capillary channel 210 during the process of returning from the heat dissipation area 420 to the heat source area 400, without internal blockage. Therefore, the working fluid has less flow resistance and a shorter flow distance, which can effectively increase the return velocity of the working fluid to the heat source area 400, thereby improving heat transfer capacity.

[0033] For ease of understanding, the following uses a capillary tube as an example to explain its working principle. For a capillary tube with a rectangular cross-section of length L, width w, and height h, the pressure difference of the fluid at both ends of the capillary tube is , the fluid flow rate is: (1), Where a is a dimensionless coefficient related to the cross-sectional shape of the capillary channel, and μ is the dynamic viscosity coefficient of the fluid. Considering the case of capillary flow climbing against gravity, the gas-liquid interface By capillary pressure and gravitational pressure Cause, that is , the capillary pressure in a closed pipe is: (2), The capillary pressure in an open pipe (one side of the width is open) is (3), Where σ is the surface tension coefficient and θ is the contact angle of the gas-liquid interface. The capillary climbing curves in these two cases can be obtained by calculation, see Figure 6 .Depend on Figure 6 It can be seen that the climbing speed of the closed pipeline is much better than that of the open pipeline.

[0034] Combine Figures 1-9As shown, the first material layer may also be provided with capillary holes 250 for connecting to the capillary channel 210. The capillary holes 250 may be provided on the sidewalls of the capillary channel 210 and the wall near the steam chamber. The second material layer is provided with steam holes 251, which are used to connect the capillary channel 210 of the first material layer and the steam chamber 103, allowing the working fluid and its vapor to flow between the capillary holes and the steam chamber.

[0035] In addition, the shapes of the vapor-liquid capillary interfaces within the vapor pores of the second material layer in the heat source region 400 and the heat dissipation region 420, due to the different regulation of the evaporation and condensation processes, form different vapor-liquid interface curvature radii, thereby generating different capillary pressures. Ultimately, a capillary pressure difference is formed across the heat source region 400 and the heat dissipation region 420, driving the working fluid from the heat dissipation region 420 back to the heat source region 400. In addition to this pressure difference, the effective capillary radius of the vapor pores in the heat source region 400 can be designed to be smaller than the effective capillary radius of the vapor pores in the heat dissipation region 420, thereby further increasing the capillary pressure that causes the working fluid to flow back to the heat source region.

[0036] The housing 100 of the heat spreader 10 is generally a sealed structure. It includes a first cover plate 101 and a second cover plate 102 positioned opposite each other, connected by several side panels. The wick 200 is located between the second cover plate 102 and the first cover plate 101. The wick 200 can be arranged in the following ways, but is not limited to: like Figure 8 As shown, one side of the wick 200 is connected to the first cover plate 101 or the second cover plate 102, and the other side of the wick 200 is the steam chamber 103. The wick 200 can be arranged on both the first cover plate 101 and the second cover plate 102, or on only one of the first cover plate 101 and the second cover plate 102.

[0037] As a possible example, for the above-described arrangement of the wick 200, the first material layer of the wick 200 is provided with capillary holes 250 for communicating with the capillary channels 210. This allows the working fluid and its vapor to flow between the capillary channels 210, thereby facilitating balanced distribution and rapid flow of the working fluid. The capillary holes 250 can be provided on the sidewalls of the capillary channels 210 and on the wall adjacent to the vapor chamber.

[0038] As a possible example, the second material layer of the wick 200 is provided with steam holes to allow the working liquid and its vapor to flow between the capillary channels 210 and between the capillary channels 210 and the steam chamber 103. In the heat source region 400, the steam holes 251 provide an evaporation interface; in the heat dissipation region 420, the steam holes 251 provide a condensation interface.

[0039] The shape and arrangement of the capillary holes 250 can be flexibly selected. The hole shape can be circular, semicircular, elliptical, crescent, triangular, square, rectangular, trapezoidal, star-shaped, bar-shaped, or a combination thereof. Irregular shapes are also possible, and the following is merely an example. The size of the capillary holes 250 is controlled to be between 0.001 microns and 500 microns, such as 1 micron, 10 microns, 50 microns, 100 microns, 200 microns, and 500 microns. The aspect ratio of the capillary holes 250 can be varied according to design requirements; the angle between the length direction of the capillary holes 250 and the capillary channel 210 can be arbitrarily varied. When the capillary holes 250 are relatively small, they can be arranged only at the bottom of the capillary channel 210, or they can be arranged also on the sidewalls of the capillary channel 210 (this configuration is not shown).

[0040] The shape and arrangement of the steam holes 251 can be flexibly selected. The hole shapes can be circular, semicircular, elliptical, crescent, triangular, square, rectangular, trapezoidal, star-shaped, strip-shaped, or a combination thereof. Irregular shapes can also be used. The following is merely an example. The size of the steam holes 251 is controlled to be between 0.001 microns and 500 microns, such as 0.05 microns, 0.5 microns, 2 microns, 10 microns, 20 microns, 50 microns, 100 microns, 200 microns, etc.

[0041] The size and spacing of the capillary channels 210 of the wick 200 can be adjusted to suit different heat dissipation requirements, and can also be adjusted at different locations on the same wick 200. For example, the width, spacing, and height of the capillary channels of the wick 200 can vary from a few nanometers to several thousand microns, such as 10 microns, 50 microns, 100 microns, 200 microns, 500 microns, 1000 microns, etc.

[0042] As a possible example, see Figure 7 The wick 200 connects the heat source region 400, the insulation region 410, and the heat dissipation region 420. The first material layer 201 of the wick 200 is provided with capillary pores 250 in the heat source region 400, the insulation region 410, and the heat dissipation region 420. The second material layer 202 of the wick 200 is provided with steam pores 251 in both the heat source region 400 and the heat dissipation region 420, but no steam pores 251 are provided in the insulation region 410. The shapes and arrangements of the capillary pores 250 and steam pores 251 can adopt the shapes described above or a combination thereof. The steam pores 251 corresponding to the wick 200 provide an evaporation interface in the heat source region 400 and a condensation interface in the heat dissipation region 420. The capillary channels 210 corresponding to the wick 200 allow the condensed working fluid in the heat dissipation region 420 to flow back to the heat source region 400 under capillary pressure.

[0043] As a possible example (not shown), the wick 200 connects the heat source region 400 and the heat dissipation region 420, without an insulating region 410 in between. The first material layer 201 of the wick 200 is provided with capillary holes 250 in both the heat source region 400 and the heat dissipation region 420. The second material layer 202 of the wick 200 is provided with steam holes 251 in both the heat source region 400 and the heat dissipation region 420. The capillary holes 250 and steam holes 251 can have the shapes described above or a combination thereof. The steam holes 251 in the wick 200 provide an evaporation interface in the heat source region 400 and a condensation interface in the heat dissipation region 420. The capillary channels 210 in the wick 200 allow the condensed working fluid in the heat dissipation region 420 to flow back to the heat source region 400 under capillary pressure.

[0044] As a possible example, the effective capillary radius of the steam holes 251 of the wick 200 located in the heat source area 400 can be designed to be smaller than the effective capillary radius of the steam holes 251 located in the heat dissipation area 420, so as to further increase the capillary pressure that causes the working fluid to flow back to the heat source area.

[0045] The first and second material layers of the wick in the above-described embodiment form a capillary channel with the housing, and the capillary holes in the capillary channel allow fluids to flow between the channels. The capillary channel is a tubular structure with a defined direction, and the cross-section of the tubular structure can be a variety of shapes, such as a semicircular, rectangular, trapezoidal, arched, a major arc arched, a minor arc arched, a triangle, or a combination thereof, or shapes similar to these. Compared to the prior art, such as groove structures or open structures (including wire mesh, sintered copper powder, and foam structures), the working fluid in the present invention flows along the capillary channel during the process of returning from the heat dissipation area to the heat source area, rather than along a path with internal obstruction. Therefore, the working fluid has less flow resistance and a shorter flow distance, which can effectively increase the return velocity of the working fluid to the heat source area, thereby improving the heat transfer capacity.

[0046] In some examples, the capillary channels in the first material layer are all closed capillary channels, thereby increasing the capillary pressure difference between the heat source area and the heat dissipation area, effectively increasing the return velocity of the working fluid to the heat source area, thereby improving heat transfer capacity. By adjusting the size of the capillary channels in the first material layer of the wick and the size of the steam pores in the second material layer, high capillary pressure and high flow rate can be achieved simultaneously. This overcomes the randomness and difficulty in controlling capillary pressure and working fluid flow in traditional solutions.

[0047] In some examples, the effective capillary radius of the steam through holes located in the heat source area is smaller than the effective capillary radius of the steam through holes located in the heat dissipation area, so as to further increase the capillary pressure causing the working fluid to flow back to the heat source area.

[0048] An embodiment of the present application further provides a temperature homogenizing plate 10, referring to Figure 8-Figure 9 and Figure 3-Figure 4 , including a liquid absorbent core 200, and also including a shell 100. The liquid absorbent core 200 is formed by combining a first material layer 201 and a second material layer 202; the first material layer 201 of the liquid absorbent core 200 has a capillary channel 210 and a capillary through-hole 250; the second material layer 202 of the liquid absorbent core 200 has a steam through-hole 251. The shell 100 generally has a first cover plate 101 and a second cover plate 102, and the first cover plate 101 and the second cover plate 102 are connected by a number of side plates, and the liquid absorbent core 200 is located between the second cover plate 102 and the first cover plate 101. The liquid absorbent core 200 is fixed on the second cover plate 102, and the steam chamber 103 is located between the liquid absorbent core 200 and the first cover plate 101. In order to show clearly, Figure 8 The side panels of the housing are omitted; only the housing cover is shown. One side of the first cover 101 or the second cover 102 of the housing 100 is intended to contact the heat source. The other sides of the first and second cover 101, 102, together with the first flow guide groove, form a capillary channel 210. The housing material of the temperature equalizer and the wick 200 can be metal (such as copper alloy, aluminum alloy, titanium alloy, stainless steel, etc.), polymer material, or a combination thereof.

[0049] Since the temperature vapor chamber 10 of this embodiment includes the above-mentioned liquid wick 200 , it also has the above-mentioned advantages of the liquid wick 200 , which will not be described in detail here.

[0050] As a possible example, see Figure 8 and Figure 9 The vapor chamber 10 also includes a support member 104, which is (completely or partially) located within the steam chamber 103 to limit the minimum height of the steam chamber 103. When the support member 104 is completely located within the steam chamber 103, the upper end of the support member 104 abuts against the wick 200, and the lower end of the support member 104 abuts against the lower cover plate. When the support member 104 is partially located within the steam chamber 103, the support member 104 passes through the wick 200, and the two ends of the support member 104 abut against the two cover plates. The provision of the support member 104 prevents the steam chamber 103 from collapsing.

[0051] Reference Figure 10 and Figure 11The embodiments of the present application further provide a heat pipe, wherein a composite liquid-absorbing wick 200 is mounted on the shell of the heat pipe 20. The liquid-absorbing wick 200 of this embodiment is formed by combining a first material layer 201 and a second material layer 202. The first material layer 201 has a guide groove, which is used to form a capillary channel 210 together with the shell 100 of the heat pipe and the second material layer 202 on the side close to the steam chamber. The shell 100 of the heat pipe and the first material layer 201, as well as the first material layer 201 and the second material layer 202, can be fixedly connected by sintering (such as eutectic sintering), welding, or bonding.

[0052] As a possible example, the first material layer 201 of the wick 200 may further be provided with capillary holes 250 for connecting to the capillary channel 210, forming a mesh structure that facilitates the balanced distribution and rapid flow of the working fluid. The capillary holes 250 may be provided on the sidewalls of the capillary channel 210 and the wall near the steam chamber.

[0053] As a possible example, the second material layer is provided with a steam through hole 251, which is used to connect the capillary channel 210 of the first material layer and the steam chamber 103, so that the working fluid and its steam can flow between the capillary through hole and the steam chamber.

[0054] As a special case of the second embodiment, refer to Figure 12 In this embodiment, the wick 200 is formed solely from a first material layer 201 and is mounted on the heat pipe 20 housing. The first material layer 201 of the wick 200 has flow guide grooves that, together with the heat pipe housing 100, form a capillary channel 210. The first material layer 201 also includes an open capillary channel 220 formed by the open flow guide grooves. This open capillary channel 220 is located on the side of the first material layer closest to the vapor chamber. The heat pipe housing and the first material layer 201 can be securely connected using methods such as sintering (e.g., eutectic sintering) and welding.

[0055] As a possible example, the first material layer 201 of the absorbent core 200 may further be provided with capillary through holes 250 for connecting with the capillary channels 210 , and may form a mesh structure, which is beneficial to the balanced distribution and rapid flow of the working fluid.

[0056] As a possible example, the first material layer 201 of the liquid wick 200 may not be provided with capillary holes 250 in certain areas (such as the insulation area), which is conducive to the rapid flow of the working liquid along the axial direction of the heat pipe. Figure 13 .

[0057] Similar to the first embodiment, in the second embodiment, the capillary channel 210 of the wick 200 and the first end of the second material layer 202 are arranged in the heat source area 400 of the heat pipe, and the second end of the capillary channel 210, the open capillary channel 220 and the second material layer 202 are arranged in the heat dissipation area 420 of the heat pipe, which are used to connect the heat source area and the heat dissipation area 420 of the heat pipe, so that the working fluid condensed in the heat dissipation area 420 can flow back to the heat source area 400 through the capillary channel 210 and the open capillary channel 220 under the action of capillary pressure.

[0058] In the second embodiment, the cross-sectional shape and size design of the capillary channel 210 and the open capillary channel 220 are the same as those in the first embodiment; in the second embodiment, the shape, density and arrangement of the capillary pores 250 of the first material layer 201 and the steam pores 251 of the second material layer 202 are the same as those in the first embodiment; they will not be repeated here.

[0059] The working principle of the absorbent core 200 in the second embodiment is the same as that in the first embodiment, and will not be described again here.

[0060] Since the heat pipe 20 of this embodiment includes the liquid wick 200 , it also has the above advantages of the liquid wick 200 , which will not be described in detail here.

[0061] As a possible example, see Figure 14 The middle of the shell is a steam chamber 103, and the wick 200 is located between the shell 100 and the steam chamber 103. The wick 200 is provided with a steam through hole 251 connecting the capillary channel 210 and the steam chamber 103, so that the working fluid and its vapor can flow between the capillary channel 210 and the steam chamber 103. The first ends of the capillary channel 210 and the second material layer 202 of the first material layer 201 of the wick 200 are arranged in the heat source area 400 of the heat pipe, and the second ends of the capillary channel 210 and the second material layer 202 are arranged in the heat dissipation area 420 of the heat pipe, so as to connect the heat source area 400 and the heat dissipation area 420 of the heat pipe, so that the working fluid condensed in the heat dissipation area 420 can flow back to the heat source area 400 through the capillary channel 210 under the action of capillary pressure. In the heat source area 400 and the heat dissipation area 420 of the heat pipe, the liquid wick 200 includes a first material layer 201 and a second material layer 202. The first material layer 201 is provided with capillary holes 250, and the second material layer 202 is provided with steam holes 251 (A-A' section, refer to Figure 11 In the middle section of the heat-insulating region 410, the second material layer may not be provided with steam holes (BB' section, see Figure 13 ) to enhance capillary flow.

[0062] As another possible example, see Figure 15The absorbent core 200 comprises a first material layer 201 and a second material layer 202. The capillary channels 210 of the first material layer 201 are all provided with capillary through holes 250, and the second material layer 202 is all provided with steam through holes 251 (A-A' section, refer to Figure 11 ). As an application of flexible arrangement of the heat source area 400 and the heat dissipation area 420.

[0063] As another possible example, see Figure 16 , a composite wick 200 is provided for installation on the shell of a flattened heat pipe 20. The flattened heat pipe can be made by flattening a prepared circular heat pipe, and the thickness of the flattening can be determined according to the actual application. The wick 200 includes a first material layer 201 and a second material layer 202. The capillary channels 210 of the first material layer 201 are all arranged with capillary through-holes 250, and the second material layer 202 is all arranged with steam through-holes 251. As another possibility of this example, the first material layer 201 and the second material layer 202 can be respectively arranged with capillary through-holes 250 or steam through-holes 251, as an application for the flexible arrangement of the heat source area 400, the insulation area 410 and the heat dissipation area 420.

[0064] This embodiment also provides a method for preparing the liquid absorbent core 200, which is used to prepare the liquid absorbent core 200. Figure 17 , including the following steps: S1. Preparation of the first material layer The first material layer 201 can be produced using a variety of methods, including electrochemical machining, laser micro-nanomachining (including 3D printing), chemical etching, micro-casting, photolithography (including electron beam lithography and focused ion beam machining), etching, micro-EDM, machining (micro-milling and micro-drilling), embossing and stamping (including nanoimprinting), ultrasonic machining, water jet cutting, dealloying, powder metallurgy, and the like. For example, in the electrodeposition method, a mold with a capillary channel shape is first prepared, and then the desired metal is electrochemically deposited on the mold. After removing the mold material, the channels required for the first material layer are obtained. In the stamping method, a mold with a capillary channel shape is first prepared, and then a thin film material is stamped out of the mold to obtain the first material layer.

[0065] The capillary holes 250 of the capillary channel of the first material layer can be prepared before or after the capillary channel is formed. The capillary holes 250 can be formed using, but are not limited to, electrochemical machining, laser micro-nanomachining, chemical etching, micro-casting, photolithography (including electron beam lithography and focused ion beam machining), etching (such as ICP, RIE, and DRIE), micro-EDM, machining (micro-milling and micro-drilling), embossing and stamping (including nanoimprinting), ultrasonic machining, water jet cutting, dealloying, powder metallurgy, and template methods (such as self-assembly, inverse opal, sol-gel, and breathing patterning). The capillary holes 250 can have shapes such as circular, semicircular, elliptical, crescent, triangular, square, rectangular, trapezoidal, star-shaped, or stripe-shaped, or combinations thereof. Irregular shapes are also possible. The first material layer may be metal (such as copper alloy, aluminum alloy, titanium alloy, stainless steel, etc.), polymer material or a combination thereof.

[0066] S2. Preparation of the second material layer The second material layer 202 may be a solid or porous film material and may be obtained using the preparation method of the first material layer 201 .

[0067] The second material layer can also be a porous dielectric material or a capillary material, such as a foam, wire mesh, sintered metal powder, or a combination thereof. The second material layer can also be made from the first material layer, that is, the first material layer is superimposed to form the second material layer. Based on this superposition principle, the second material layer can be formed by stacking multiple layers of materials according to application requirements. The materials used in each layer can be the same or different. Options include the first material layer, wire mesh, and film. The steam pores 251 in the second material layer 202 can be formed using the same method as the capillary pores 250. The shape of the steam pores 251 can adopt the shape of the capillary pores 250. The second material layer can be made of a metal (such as a copper alloy, aluminum alloy, titanium alloy, stainless steel, etc.), a polymer material, or a combination thereof.

[0068] S3. Preparation of composite liquid-absorbing core materials The first material layer 201 and the second material layer 202 are formed into the composite absorbent core 200 by welding, sintering, bonding, etc.

[0069] As a possible example, the thickness of the first material layer 201 can be determined according to the size of the heat sink or the heat pipe, and the thickness can vary from a few nanometers to several thousand micrometers, such as 0.01 micrometer to 200 micrometers.

[0070] As a possible example, the size of the capillary holes 250 and the steam holes 251 (such as radius or length and width) can be determined according to the heat dissipation requirements of the heat spreader, the speed requirements of the capillary circulation of the working fluid, and the working conditions (such as the influence of gravity or other acceleration effects). This size can vary from a few nanometers to 1000 microns, but the general application size is controlled between 0.1 microns and 100 microns.

[0071] The absorbent core 200 prepared according to the above method has a greater capillary pressure when transporting the working fluid and a smaller flow resistance of the working fluid, and is therefore more effective. In order to verify the advanced nature of this absorbent core 200, we prepared a absorbent core 200 and conducted an experimental comparison with the commonly used copper wire mesh material. The length of both is 100 mm. The copper wire mesh material is 300 mesh, the diameter of the copper wire therein is 30 microns, and the total thickness of the copper wire mesh material is 60 microns; the total thickness of the absorbent core 200 prepared according to the preparation method of this embodiment is 40 microns. The absorbent core 200 is arranged with square steam holes 251, and the length and width are both 40 microns. The absorbent core 200 and the copper wire mesh material are sintered on a copper sheet (equivalent to a cover plate) through the same heat treatment process to obtain a sintered structure (the sintered structure of the absorbent core 200 and the cover plate is shown in FIG. Figure 3 After cleaning, drying, and reducing, the two sintered structures were immersed at one end in deionized water. A camera was used to capture the water's rise through the material. Image analysis was then used to measure the water surface position at each time point.

[0072] Figure 18 The climbing time curve of the wick 200 prepared according to the preparation method of this embodiment is shown in FIG. , and compared with the water climbing time curve of the copper wire mesh material, the climbing speed and height of the wick 200 prepared according to the preparation method of this embodiment are far superior to the sintered structure of the copper wire mesh material.

[0073] The above description is only a preferred embodiment of the embodiments of the present application, and does not limit the scope of disclosure of the embodiments of the present application. Any equivalent structure or equivalent process transformation made using the embodiment description and drawings of the present application, or directly or indirectly applied in other related technical fields, are also included in the scope of patent protection supported by the embodiments of the present application.

Claims

1. The composite liquid wick is installed in the heat conducting element housing, characterized in that: include: A first material layer having a first surface and a second surface, wherein the first surface and the second surface respectively have guide grooves, and the guide grooves on the first surface and the heat-conducting element housing together form a capillary channel; a second material layer adhered to the second surface of the first material layer and forming a capillary channel together with the guide groove on the second surface of the first material layer; The capillary tube is used to connect the heat source area and the heat dissipation area, so that the phase change heat transfer medium condensed in the heat dissipation area can flow back to the heat source area through the capillary tube under the action of capillary pressure.

2. The composite absorbent core according to claim 1, wherein The first material layer is a capillary material layer, the second material layer is a dielectric material layer or a capillary material layer, or a multilayer stack of the dielectric material layers or capillary material layers, and the dielectric material layer includes a solid dielectric material layer and a porous dielectric material layer.

3. The composite absorbent core according to claim 1, wherein A steam chamber is provided in the heat-conducting element shell, the second material layer is provided on one side of the steam chamber, the first material layer is provided between the heat-conducting element shell and the second material layer, and a capillary through-hole is provided on the capillary channel of the first material layer. The capillary through-hole is used to connect the capillary channel and the steam chamber so that the phase change heat transfer medium and its steam can flow between the capillary channels of the first material layer.

4. The composite absorbent core according to claim 3, wherein The second material layer further has a steam through hole, which is used to connect the capillary channel and the steam chamber, so that the phase-change heat transfer medium and its steam can flow between the capillary channel of the first material layer and the steam chamber.

5. The composite absorbent core according to claim 1, wherein The first ends of the first material layer and the second material layer are used to be placed in the heat source area, and the second ends of the first material layer and the second material layer are used to be placed in the heat dissipation area; so that the phase change heat transfer medium condensed in the heat dissipation area can flow back to the heat source area through the capillary channel of the first material layer under the action of capillary pressure.

6. The composite absorbent core according to claim 4, characterized in that The effective capillary radius of the steam through hole at the first end of the second material layer is smaller than the effective capillary radius of the steam through hole at the second end of the second material layer, so as to increase the capillary pressure for the phase change heat transfer medium to flow back to the heat source area.

7. A temperature equalizing plate, characterized in that: The composite absorbent core according to any one of claims 1 to 6 further comprises a shell; the shell has a cover plate, one side of the cover plate is used to contact a heat source, and the other side of the cover plate and the first material layer together form the capillary channel.

8. The temperature vapor chamber according to claim 7, wherein: The shell has a steam chamber, which is located on one side of the second material layer; a steam through hole is provided on the second material layer, which is used to connect the capillary tube of the first material layer and the steam chamber, so that the phase change heat transfer medium and its steam can flow between the capillary tube of the first material layer and the steam chamber.

9. A heat pipe, characterized in that The composite absorbent core according to any one of claims 1 to 6 further comprises a shell; one side of the shell is used to contact a heat source, and the other side of the shell and the first material layer together form a capillary channel of the first material layer.

10. The heat pipe according to claim 9, characterized in that The shell has a steam chamber, which is located on one side of the second material layer; the second material layer is provided with a steam through hole, which is used to connect the capillary tube and the steam chamber to allow the phase change heat transfer medium and its steam to flow between the capillary tube and the steam chamber.

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