Liquid absorption core with bionic air hole structure and preparation method and application of liquid absorption core

Abstract

The invention relates to the field of heat dissipation, is inspired by a plant pore structure, and designs a bionic pore structure liquid absorption core, which comprises a liquid transport channel, bionic pores, a flexible film substrate, a cylindrical support column, a liquid transport channel array and a bionic pore array, so as to simulate the excellent liquid transport and gas-liquid exchange performance of plant pores in nature. The liquid absorbing core with the bionic air hole structure can be integrated into an ultra-thin vapor chamber, so that the heat dissipation performance of electronic equipment is remarkably improved, the hot spot temperature is reduced, stable operation of the equipment under high load is ensured, and the heat exchange efficiency is further optimized. The preparation method and the application show the advantages in multiple aspects, not only promote the development of a heat management technology, but also provide powerful support for the design and implementation of an efficient, reliable and safe heat exchange system in the future, and have wide application prospects.

Description

Technical Field

[0001] The invention relates to the field of heat dissipation, and in particular to a preparation method and application of a bionic pore structure liquid absorbent core. Background Art

[0002] With the continuous improvement of the performance of electronic devices, especially the rapid development of high-performance computing, 5G communications, and high-end graphics processing, thermal management inside the equipment has become a technical challenge that needs to be solved urgently. Traditional heat dissipation technologies, such as fans and heat sinks, have been unable to meet the growing demand for heat dissipation, especially in modern electronic devices that pursue lightweight design and high power density. Against this background, ultra-thin heat spreaders have emerged as a new type of heat dissipation solution. As a key component for ultra-thin heat spreaders to transfer heat, the wick structure plays a key role in improving heat dissipation efficiency. Compared with traditional wicks, bionic wicks, as a new structure that imitates natural organisms, can more easily adapt to different environmental conditions and improve versatility in various applications.

[0003] After millions of years of natural evolution and selection, pores have formed a unique liquid transport functional system. Through the capillary force of the microchannel, the pores spontaneously guide the liquid to flow to the heat source area and evaporate after heating. The high-temperature steam generated is quickly transmitted to the colder area through the pores for condensation and reflux, forming a continuous phase change cycle, thereby achieving efficient heat exchange and transfer, effectively reducing the temperature of electronic equipment, and improving the overall thermal management performance; inspired by this, a bionic pore structure liquid absorbent core was developed, which is of great significance for its reliability and safety. Summary of the invention

[0004] The purpose of the present invention is to provide a bionic pore structure liquid absorbent core, which is designed to imitate the pore structure of plants in nature, control the flow of liquid through micron-level channels, and spontaneously guide the liquid to the area that needs to be cooled without external pumping, thereby improving the heat exchange efficiency. At the same time, the design of the bionic pores ensures the rapid transmission of high-temperature steam and the stable reflux of condensed liquid, further improving the heat exchange efficiency.

[0005] In a first aspect, an embodiment provides a bionic pore structure liquid-absorbing core, comprising a liquid transport channel, a bionic pore, a flexible film substrate, a cylindrical support column, a liquid transport channel and a bionic pore.

[0006] The liquid transport channel and the bionic pores are both array structures.

[0007] The liquid transport channel array and the cylindrical support column are located on a flexible film substrate and are obtained by laser direct writing and etching.

[0008] The bionic pores are located in the liquid transport channel and are obtained by laser penetration impact.

[0009] In some embodiments of the first aspect, a cross-sectional shape of the liquid transport channel is conical or trapezoidal.

[0010] The width of the liquid transport channel is greater than or equal to 500 μm, and the depth of the liquid transport channel is less than or equal to 300 μm.

[0011] The interval between adjacent liquid transport channels is greater than or equal to 50 μm.

[0012] In some embodiments of the first aspect, a cross-sectional shape of the bionic pore is circular.

[0013] The radius of the bionic pores is greater than or equal to 300 μm, the height of the bionic pores is the same as the thickness of the flexible film substrate, and the spacing between adjacent bionic pores is greater than or equal to 1 mm.

[0014] In some embodiments of the first aspect, the thickness of the flexible film substrate is less than or equal to 1 mm.

[0015] In some embodiments of the first aspect, the thickness of the cylindrical support column is the same as the thickness of the flexible film substrate, the radius of the cylindrical support column is greater than or equal to 500 μm, and the spacing between adjacent cylindrical support columns is greater than or equal to 3 mm.

[0016] In some embodiments of the first aspect, the material of the liquid transport channel, the bionic pores, the flexible film substrate and the cylindrical support column includes at least one or more of pure copper, copper oxide, copper alloy, aluminum, aluminum alloy, titanium and titanium alloy.

[0017] In a second aspect, the embodiment further provides a method for preparing a bionic pore structure absorbent core, comprising the following steps:

[0018] S1. Fix the flexible film substrate on the workbench with a clamp, and scan a specific path on the flexible film substrate by short-pulse laser direct writing etching to process a series of liquid transport channels and cylindrical support columns.

[0019] S2. A series of bionic pores are processed in the formed liquid transport channel by short pulse laser penetration impact.

[0020] S3. Use a welding machine to weld two bionic air pore structure liquid absorbent cores to the upper and lower bottom plates, so that the cylindrical support columns overlap with each other to form a supporting effect. Through a series of process flows such as liquid injection and vacuuming, a bionic air pore structure liquid absorbent core heat sink with a certain closed vacuum cavity is prepared.

[0021] In some embodiments of the second aspect, the short pulse laser processing comprises:

[0022] A short-pulse laser is used to quantitatively remove a specific width and depth by direct writing ablation, and a liquid transport channel with a conical or trapezoidal cross-sectional shape is obtained by changing the parameters of the short-pulse laser; and

[0023] A short pulse laser is used in a penetrating impact manner to obtain biomimetic pores in a liquid transport channel with specific short pulse laser parameters.

[0024] The pulse half-width of the short-pulse laser is less than or equal to 200 ns.

[0025] The spot diameter of the short pulse laser is greater than or equal to 1 μm and less than or equal to 100 μm.

[0026] The scanning times of the short pulse laser is greater than or equal to 10 times.

[0027] The energy distribution of the short pulse laser is Gaussian distribution or flat-top distribution.

[0028] In some embodiments of the first aspect, the welding is one of cold welding, resistance welding, and laser welding.

[0029] In a third aspect, the embodiment further provides an ultra-thin heat spreader using a bionic pore structured liquid wick.

[0030] The ultra-thin heat spreader has a number of liquid-absorbing cores with a bionic pore structure that is greater than or equal to 1 and less than or equal to 3.

[0031] The ultra-thin heat spreader has a thickness of less than or equal to 2 mm, a width of greater than or equal to 10 mm, and a length of greater than or equal to 10 mm.

[0032] The weight of the ultra-thin heat spreader is less than or equal to 50g, and the vacuum degree is less than or equal to 5Pa;

[0033] The working medium of the ultra-thin heat spreader is one of deionized water, methanol, ethanol and acetone.

[0034] The beneficial effects of the present invention are as follows:

[0035] The bionic pore structure liquid absorbent core of the present invention controls the flow of liquid through micron-level channels, imitating the pore structure of plants in nature, and spontaneously guides the liquid to flow to the area that needs cooling. This design improves the heat exchange efficiency. At the same time, the design of the bionic pores ensures the rapid transmission of high-temperature steam and the stable reflux of condensed liquid, further enhancing the heat exchange efficiency.

[0036] The design of the bionic pore structure liquid-absorbing core of the present invention is inspired by plants and is the result of millions of years of natural evolution and selection. It forms a structure that adapts to different environmental conditions and shows good versatility in various applications.

[0037] The bionic pore structure wick of the present invention is easy to be integrated into various devices, whether portable devices, large servers or devices in special environments, allowing the structure and size of the wick to be adjusted according to specific thermal management requirements to achieve customized solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 Schematic diagram of the structure of plant stomata.

[0040] Figure 2 It is a schematic diagram of the overall structure of the bionic pore structure liquid absorbent core of the present invention.

[0041] Figure 3 The figure is a top view of the overall structure of the bionic pore structure liquid absorbent core of the present invention.

[0042] Figure 4 The schematic diagram is a structural diagram of a unit of the bionic pore structure liquid absorbent core of the present invention.

[0043] Figure 5 It is a partial three-dimensional structural schematic diagram of the bionic pore structure liquid absorbent core of the present invention.

[0044] Figure 6 It is a structural schematic diagram of the overall cross section of an embodiment of the present invention.

[0045] Figure 7 Schematic diagram of the working structure of an ultra-thin heat spreader with a bionic pore structure wick.

[0046] Figure 8 Flow chart for preparing bionic porous structure absorbent core.

[0047] In the figure:

[0048] 1. Liquid transport channel; 2. Bionic pores; 3. Flexible film substrate; 4. Cylindrical support column; 5. Bottom plate; 6. Bionic pore array; 7. Liquid transport channel array; 8. Heating source; 9. Bionic pore structure liquid absorption core. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments will be described clearly and completely below in conjunction with the drawings in the embodiments. Obviously, the described embodiments are only a part of the embodiments, rather than all the embodiments.

[0050] The present invention provides a preparation method and application of a bionic pore structure liquid absorbent core, the core idea of ​​which is to imitate the pore structure of plant leaves, such as, Figure 1 As shown; short pulse lasers are used to process micron-scale liquid transport channels and bionic pores on a flexible film substrate to form an efficient liquid transport and vapor transmission network. By optimizing material selection and structural design, self-driven liquid flow and rapid heat exchange without external pumping can be achieved, which can effectively improve the heat dissipation performance of the ultra-thin heat spreader. Specifically, the following will be explained with specific embodiments and comparative examples. It should be pointed out that if there are processes that are not specifically described in detail below, they can be implemented or understood by those skilled in the art with reference to the prior art. Reagents or instruments used without indicating the manufacturer are deemed to be conventional products that can be purchased commercially.

[0051] Example

[0052] A schematic diagram of a bionic pore structure liquid absorbent core of this embodiment is shown in FIG. Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, it includes a liquid transport channel 1, a bionic pore 2, a flexible film substrate 3, a cylindrical support column 4, a bionic pore array 6, and a liquid transport channel array 7; the liquid transport channel 1 and the cylindrical support column 4 are processed from the flexible film substrate 3 by laser direct writing etching; and the bionic pore 2 is processed from the flexible film substrate 3 by laser penetration impact. The liquid transport channel 1 is opened on the upper surface of the flexible substrate film 4. As the main liquid channel, it can increase the contact area of ​​the liquid, improve the liquid absorption speed and distribution uniformity, and guide the liquid to flow quickly to the evaporation area; the bionic pore 2 is opened inside the liquid transport channel 1 to ensure the rapid transmission of high-temperature steam and the stable reflux of the condensed liquid. The cylindrical support columns 4 are in contact with each other and combined with the bottom plate to play a supporting role. The linear array laser processing in the flexible film substrate 3 forms the liquid transport channel array 7. The linear array laser processing in the liquid transport channel array 7 forms the bionic pore array 6.

[0053] The preparation method of the bionic pore structure liquid absorbent core comprises the following steps:

[0054] S1. Fix the flexible film substrate on the workbench with a clamp, and scan a specific path on the flexible film substrate by short-pulse laser direct writing etching to process a series of liquid transport channels and cylindrical support columns.

[0055] S2. A series of bionic pores are processed in the formed liquid transport channel by short pulse laser penetration impact.

[0056] S3. Use a welding machine to weld two bionic air pore structure liquid absorbent cores to the upper and lower bottom plates, so that the cylindrical support columns overlap with each other to form a supporting effect. Through a series of process flows such as liquid injection and vacuuming, a bionic air pore structure liquid absorbent core heat sink with a certain closed vacuum cavity is prepared.

[0057] The short pulse laser treatment comprises:

[0058] A short pulse laser is used to quantitatively remove a specific width and depth by direct writing ablation. By changing the parameters of the short pulse laser, a liquid transport channel with a conical or trapezoidal cross-sectional shape is obtained. A short pulse laser is used in a penetrating impact manner with specific short pulse laser parameters to obtain bionic pores in the liquid transport channel.

[0059] The welding is one of cold welding, resistance welding and laser welding.

[0060] In this embodiment, the material of the liquid transport channel, the bionic pores, the flexible film substrate 3 and the cylindrical support column 4 includes at least one or more of pure copper, copper oxide, copper alloy, aluminum, aluminum alloy, titanium and titanium alloy.

[0061] Specifically, the material of the liquid transport channel, the bionic pores and the flexible film substrate 3 is preferably pure copper, which has lower thermal resistance, better medium compatibility and excellent stability, and can be used stably for a long time;

[0062] Specifically, the size of the flexible film substrate is 60*60*0.3 mm 3 Pure copper sheet.

[0063] In this embodiment, the above-mentioned liquid transport channel 1, bionic pores 2, flexible film substrate 3, cylindrical support column 4, bionic pore array 6 and liquid transport channel array 7 are obtained by direct etching or penetrating impact of a pure copper sheet surface by short pulse laser in the air.

[0064] The short pulse laser scanning parameters are: the laser pulse half-width is about 200ns, the focus spot diameter is about 20μm, the number of scans of the focus spot is 10 times, and the energy distribution of the short pulse laser is Gaussian distribution.

[0065] After processing, the width of the liquid transport channel is about 500μm, the depth is about 300μm, the spacing of the liquid transport channel is about 50μm, and the cross-sectional shape is conical; the radius of the bionic pore is about 300μm, the depth is about 300μm, the spacing of the bionic pore is about 1mm, and the cross-sectional shape is circular; the thickness of the cylindrical support column is about 300μm, the radius is about 500μm, and the spacing of the cylindrical support columns is about 3mm.

[0066] The schematic diagram of the processed bionic pore structure liquid absorbent core is as follows Figure 2 , Figure 3 , Figure 4 and Figure 5 shown.

[0067] In addition, an ultra-thin heat spreader of a biomimetic porous structure wick in an application embodiment is also provided, and a specific structural schematic diagram is shown in FIG. Figure 7 The ultra-thin vapor chamber has two liquid-absorbing cores with a bionic pore structure, and has a minimum thermal resistance of about 0.18K / W at a test power of 100W.

[0068] The thickness of the ultra-thin heat spreader is less than or equal to 2 mm, the width is greater than or equal to 10 mm, and the length is greater than or equal to 10 mm.

[0069] The weight of the ultra-thin heat spreader is less than or equal to 50g, and the vacuum degree is less than or equal to 5Pa.

[0070] The working medium of the ultra-thin heat spreader is one of deionized water, methanol, ethanol and acetone; specifically, the working medium of the ultra-thin heat spreader is preferably deionized water.

[0071] Comparative Example 1

[0072] This example was prepared by referring to the preparation method of the embodiment. The difference between this example and the embodiment is that the short pulse laser did not process the liquid transport channel, and other processing parameters remained unchanged. This liquid wick structure with only bionic pores and bionic pore arrays, due to the lack of liquid transport channels, may not be able to evenly distribute the working liquid on the entire surface of the liquid wick, resulting in excessive liquid in some areas and insufficient liquid in other areas. In addition, high-temperature steam may not be able to effectively flow back to the heat source area after condensation, which will hinder the recirculation of steam and affect the heat exchange efficiency. Compared with the embodiment, the thermal resistance of the ultra-thin heat spreader prepared in this comparative example becomes larger.

[0073] Comparative Example 2

[0074] This example is prepared by referring to the preparation method of the embodiment. The difference between this example and the embodiment is that the short pulse laser does not process the bionic pores, and the other processing parameters remain unchanged. The bionic pores not only contribute to the transmission of steam, but also promote the reflux of liquid to a certain extent. This wick structure having only liquid transport channels and liquid transport channel arrays may make it difficult for the condensed liquid to flow back to the heat source area due to the lack of bionic pores, thereby affecting the circulation efficiency of the wick. In addition, the lack of bionic pores may cause heat to accumulate in certain areas, increasing the risk of equipment overheating. Compared with the embodiment, the thermal resistance of the ultra-thin heat spreader obtained in this comparative example becomes larger.

[0075] Although the embodiments of the present application have been shown and described above, the scope of protection of the present invention is not limited thereto, and any changes or substitutions that are not conceivable through creative work should be included in the scope of protection of the present invention; unless explicitly stated, any elements, actions or instructions used in this document should not be interpreted as critical or necessary.

Claims

1. A bionic pore structure absorbent core, characterized in that: It includes a liquid transport channel, a bionic pore, a flexible film substrate, a cylindrical support column, a liquid transport channel and a bionic pore; The liquid transport channel and the bionic pores are both array structures; The liquid transport channel array and cylindrical support pillars are located on a flexible film substrate and are obtained by laser direct writing etching; The bionic pores are located in the liquid transport channel and are obtained by laser penetration impact.

2. The bionic pore structure absorbent core according to claim 1, characterized in that: The cross-sectional shape of the liquid transport channel is conical or trapezoidal; The width of the liquid transport channel is greater than or equal to 500 μm, and the depth of the liquid transport channel is less than or equal to 300 μm; The interval between adjacent liquid transport channels is greater than or equal to 50 μm.

3. The bionic pore structure absorbent core according to claim 1, characterized in that: The cross-sectional shape of the bionic pore is circular; The radius of the bionic pores is greater than or equal to 300 μm, the height of the bionic pores is the same as the thickness of the flexible film substrate, and the spacing between adjacent bionic pores is greater than or equal to 1 mm.

4. The bionic pore structure absorbent core according to claim 1, characterized in that: The thickness of the flexible film substrate is less than or equal to 1 mm.

5. The bionic pore structure absorbent core according to claim 1, characterized in that: The thickness of the cylindrical support column is the same as that of the flexible film substrate, the radius of the cylindrical support column is greater than or equal to 500 μm, and the distance between adjacent cylindrical support columns is greater than or equal to 3 mm.

6. The bionic pore structure absorbent core according to claim 2 or 3 or 4 or 5, characterized in that: The material of the liquid transport channel, bionic pores, flexible film substrate and cylindrical support column at least includes one or more of pure copper, copper oxide, copper alloy, aluminum, aluminum alloy, titanium and titanium alloy.

7. The method for preparing a bionic porous structure absorbent core according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Fix the flexible film substrate on the workbench with a fixture, and scan a specific path on the flexible film substrate by short-pulse laser direct writing etching to process a series of liquid transport channels and cylindrical support columns; S2, processing a series of bionic pores in the formed liquid transport channel by short pulse laser penetration shock; S3. Use a welding machine to weld two bionic air pore structure liquid absorbent cores to the upper and lower bottom plates, so that the cylindrical support columns overlap with each other to form a supporting effect. Through a series of process flows such as liquid injection and vacuuming, a bionic air pore structure liquid absorbent core heat sink with a certain closed vacuum cavity is prepared.

8. The method for preparing the bionic pore structure absorbent core according to claim 7, characterized in that: The short pulse laser treatment comprises: A short-pulse laser is used to quantitatively remove a specific width and depth by direct writing ablation, and a liquid transport channel with a conical or trapezoidal cross-sectional shape is obtained by changing the parameters of the short-pulse laser; and Using short pulse laser in a penetrating impact manner and with specific short pulse laser parameters, biomimetic pores are obtained in the liquid transport channel; The pulse half-width of the short-pulse laser is less than or equal to 200ns; The spot diameter of the short pulse laser is greater than or equal to 1 μm and less than or equal to 100 μm; The number of scans of the short pulse laser is greater than or equal to 10 times; The energy distribution of the short pulse laser is Gaussian distribution or flat-top distribution.

9. The method for preparing the bionic pore structure absorbent core according to claim 7, characterized in that: The welding is one of cold welding, resistance welding and laser welding.

10. An ultra-thin vapor chamber using the bionic pore structure liquid absorbent core according to any one of claims 1 to 6, characterized in that: The number of the liquid-absorbing cores with a bionic pore structure on the ultra-thin vapor chamber is greater than or equal to 1 and less than or equal to 3; The ultra-thin heat spreader has a thickness of less than or equal to 2 mm, a width of greater than or equal to 10 mm, and a length of greater than or equal to 10 mm; The weight of the ultra-thin heat spreader is less than or equal to 50g, and the vacuum degree is less than or equal to 5Pa; The working medium of the ultra-thin heat spreader is one of deionized water, methanol, ethanol and acetone.

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