Fiber wick ultrathin vapor chamber and preparation method thereof

Abstract

The invention discloses a fiber wick ultrathin vapor chamber which comprises an upper base plate and a lower base plate, hanging columns are installed on one base plate and installed at the two ends of the base plate, and a gap exists between every two adjacent hanging columns located at the same end. The fiber liquid absorption core can be sequentially wound from the hanging columns at the two ends and is tensioned and fixed to form a circuitous shape, and the fiber liquid absorption core fastened on the hanging columns is fixed between the two base plates through the other base plate. The fiber wick can be sequentially wound and fixed on the hanging column and tensioned, through mechanical connection and fixation, the problem that in the preparation or use process of the vapor chamber, due to thermal stress deformation, the wick falls off or shifts, the vapor chamber loses efficacy can be effectively solved, the use stability of the vapor chamber is improved, accurate positioning is facilitated through the layout, and the service life of the vapor chamber is prolonged. The installation process is simplified, and the preparation efficiency of the vapor chamber is improved.

Description

Technical Field

[0001] The invention relates to the technical field of vapor chamber manufacturing, and in particular to an ultra-thin vapor chamber with a fiber liquid-absorbing core and a preparation method thereof. Background Art

[0002] As satellites’ requirements for data processing capabilities continue to increase, onboard data processors, phased array antennas and other devices are gradually developing towards miniaturization and high integration, resulting in a significant increase in the heat flux density of chips. This high heat flux density places higher demands on the satellite’s cooling system. If the heat of the chip cannot be effectively managed, it will directly threaten the satellite’s operational stability and service life. In the aerospace field, thermal control devices must meet the requirements of high performance, light weight and long life, and traditional heat spreaders are difficult to fully meet these stringent application requirements in terms of thickness, heat dissipation efficiency and structural stability.

[0003] The patent publication number is CN 114025562 A, and the patent name is a prior art of a heat spreader with a gradient liquid wick structure and a preparation method thereof. It specifically discloses that "the heat spreader includes an upper shell plate, a condensation end liquid wick, a support column, an evaporation end liquid wick, a lower shell plate and a liquid injection pipe; wherein: the inner surface of the lower shell plate can be a plane or a stepped concave surface, which can be divided into different areas according to the relative position of the contact area with the heat source, and the evaporation end liquid wick is a composite porous medium with different capillary pore sizes and porosities, and the capillary pore size and porosity change with the position of different areas. The absorbent core involved in the above technology is made of metal powder and pore-forming agent mixed and sintered or metal mesh sintered, not fiber sintered absorbent core. The fiber sintered absorbent core has the characteristics of thin thickness, changeable shape and stable structure, which can meet the requirements of ultra-thin and high stability. The sintered powder absorbent core used in the above technology is difficult to meet the requirements of high stability because the sintered powder can easily fall off or crack due to thermal shock or thermal expansion during use.

[0004] The patent publication number is CN 113048823 A, and the patent name is a prior art of a ceramic heat spreader structure with a composite liquid absorbent core based on a casting method and a method for making the same. It specifically discloses "a heat spreader, a composite liquid absorbent core and a working fluid, the heat spreader includes an upper plate body and a lower plate body, a chamber is provided between the upper plate body and the lower plate body; the bottom side of the upper plate body and the inner side of the lower plate body are both provided with a plurality of grooves, the grooves on the upper plate body and the lower plate body are arranged side by side, the interior of the heat spreader is covered with a wire mesh liquid absorbent core or a sintered powder plate liquid absorbent core on the inner side of the upper plate body and the lower plate body, the wire mesh liquid absorbent core or the sintered powder plate liquid absorbent core and the adjacent plurality of the grooves constitute a cavity. Composite liquid absorbent core; the working fluid is sealed in the chamber of the heat spreader. "The liquid absorbent core involved in the above technology adopts a wire mesh liquid absorbent core or a sintered powder plate liquid absorbent core. The powder liquid absorbent core heat spreader uses a powder liquid absorbent core. During use, thermal shock or thermal expansion can easily cause the sintered powder to fall off or crack, resulting in failure of the heat spreader. Its structure is unstable and cannot be used in equipment in fields such as aerospace that require extremely high stability. The fiber sintered liquid absorbent core has the characteristics of thin thickness, changeable shape and stable structure. The heat spreader using the fiber liquid absorbent core can meet the high stability requirements, while the above technology is difficult to meet the high stability requirements due to the structural limitations of the liquid absorbent core.

[0005] The wick structure inside the vapor chamber provides power (capillary pressure) and flow channels for the reflux of condensed liquid, and is the key to achieving gas-liquid phase change heat transfer in the vapor chamber. Since the internal space of the ultra-thin vapor chamber is extremely compressed, the structure of its wick is also quite different from that of an ordinary vapor chamber. The fiber sintered wick has become a commonly used wick structure in ultra-thin vapor chambers due to its advantages such as thin thickness, changeable shape, and stable structure. However, the fibers in the fiber sintered wick are only partially in contact with the vapor chamber substrate, and the bonding force is weak, which can easily cause the wick to fall off or shift, thereby affecting the stability of the vapor chamber. In addition, the traditional vapor chamber adopts upper and lower substrate plane contact welding, the welding surface is narrow and slender, the bonding strength is low, and long-term use may lead to safety hazards such as leakage. Summary of the invention

[0006] The technical problem to be solved by the present invention is how to solve the problem that the existing liquid absorbent core structure is easy to fall off or shift, thus causing instability.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] A fiber liquid-absorbing core ultra-thin heat-absorbing plate, comprising two sets of upper and lower substrates, one of which is provided with a hanging column, the hanging column being installed at both ends of the substrate, and a gap being provided between two adjacent hanging columns at the same end;

[0009] It also includes a fiber liquid-absorbent core, which can be wound around the hanging columns at both ends in sequence and tightened to form a circuitous shape. Another base plate fixes the fiber liquid-absorbent core fastened on the hanging column between the two base plates.

[0010] The present application sets a number of hanging posts at both ends of the substrate, and the fiber wick can be wound and fixed on the hanging posts in sequence and tightened. By mechanically connecting and fixing, it can effectively avoid the heat spreader from falling off or shifting due to thermal stress deformation during the preparation or use of the heat spreader, thereby improving the stability of the heat spreader. The fiber wick is arranged in a ring-shaped manner and wound on the lower substrate and is pressed and fixed by the upper substrate. This layout facilitates precise positioning, simplifies the installation process, and improves the preparation efficiency of the heat spreader.

[0011] As a further solution of the present invention: the fiber absorbent core can be selected from but not limited to copper fiber absorbent core, aluminum fiber absorbent core and stainless steel fiber absorbent core.

[0012] As a further solution of the present invention: the fiber absorbent core as a whole is a woven fiber belt formed by a plurality of fibers.

[0013] As a further solution of the present invention: a plurality of support columns are provided on the substrate and between the two end hanging columns, and the other ends of the support columns abut against another substrate.

[0014] As a further solution of the present invention: the substrate comprises a lower substrate and an upper substrate, the hanging column and the fiber absorbent core are installed in the embedded cavity of the lower substrate, and a circle of bosses cooperating with the cavity is provided on the side of the upper substrate facing the lower substrate.

[0015] The present invention also discloses a method for preparing an ultra-thin soaking plate of a fiber liquid-absorbing core, comprising the following steps:

[0016] S1. Preparation of heat spreader substrate:

[0017] An inner cavity, supporting columns and hanging columns are processed on a metal substrate to obtain a lower substrate;

[0018] A boss is machined on another metal base plate of the same size to obtain an upper base;

[0019] S2. Installation of fiber absorbent core structure:

[0020] The fiber liquid-absorbing core surrounds the hanging column in the inner cavity of the lower base plate;

[0021] The head end of the fiber liquid-absorbing core is fixed on the lower base plate by resistance spot welding;

[0022] Then, the fiber absorbent core is tightened to be evenly arranged on the inner surface of the lower substrate, and the tail end is fixed by resistance spot welding, and the fiber absorbent core is sintered at a high temperature to be fastened to the lower substrate;

[0023] S3, heat sink package:

[0024] The prepared lower substrate with a fiber wick structure is spliced ​​with the upper substrate, the base surfaces of the upper and lower substrates are welded and sealed, and then vacuuming, pouring phase change heat transfer medium and sealing are performed to prepare a heat spreader.

[0025] As a further solution of the present invention: the welding method in step S3 adopts but is not limited to diffusion welding and brazing.

[0026] As a further solution of the present invention: the perfusion phase change heat transfer medium in step S3 can be but is not limited to deionized water, refrigerant and ethanol.

[0027] As a further solution of the present invention: the resistance spot welding current in step S2 is 3.4A, and the over-current time is 200ms.

[0028] As a further solution of the present invention: the temperature of high-temperature sintering of the fiber absorbent core in step S2 is 750-950°C.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] First, the present application sets a number of hanging posts at both ends of the substrate, and the fiber wick can be wound and fixed on the hanging posts in sequence and tightened. By mechanically connecting and fixing, it can effectively avoid the problem of the wick falling off or shifting due to thermal stress deformation during the preparation or use of the heat spreader, thereby improving the use stability of the heat spreader. The fiber wick is arranged in an annular manner and wound on the lower substrate and is pressed and fixed by the upper substrate. This layout facilitates precise positioning, simplifies the installation process, and improves the preparation efficiency of the heat spreader.

[0031] Secondly, the fiber absorbent core of the present application is wound and arranged on the hanging column of the lower substrate. By setting the hanging column structure, the number of structures of the absorbent core can be arranged more reasonably and the absorbent core can be arranged more evenly, making the design of the heat spreader more flexible and reliable, and can adapt to different application requirements;

[0032] Finally, the upper substrate of the heat spreader of the present application is designed with a closed annular boss. When the upper and lower substrates are connected, the boss is inserted into the inner cavity of the lower substrate, increasing the welding contact area and providing a labyrinth sealing effect, thereby improving the sealing reliability and welding stability of the heat spreader. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1This is a schematic diagram of the structure when the fiber liquid-absorbing core is not installed on the lower substrate of an embodiment of the present invention;

[0034] Figure 2 It is a structural schematic diagram of the upper substrate in an embodiment of the present invention;

[0035] Figure 3 This is a front view of the fiber liquid absorbent core installed on the lower substrate of the embodiment of the present invention;

[0036] Figure 4 An exploded view of an ultra-thin vapor chamber of a fiber absorbent core according to an embodiment of the present invention;

[0037] Figure 5 A cross-sectional view of an ultra-thin vapor chamber of a fiber absorbent core according to an embodiment of the present invention;

[0038] Description of reference numerals:

[0039] 1. Lower substrate; 2. Cavity; 3. Support column; 4. Hanging column; 5. Upper substrate; 6. Boss; 7. Fiber wick. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Reference Figure 1 , Figure 2 and Figure 4 A fiber liquid-absorbing core ultra-thin heat spreader includes a lower substrate 1, an upper substrate 5 and a fiber liquid-absorbing core 7, wherein a cavity 2 is provided on the side where the lower substrate 1 is connected to the upper substrate 5, a support column 3 and a hanging column 4 are both installed in the cavity 2 of the lower substrate 1, and a boss 6 is provided on the side where the upper substrate 5 is connected to the lower substrate 2, and the boss 6 can just completely engage and fix the cavity 2.

[0042] Reference Figure 1 The lower substrate 1 is a copper substrate, and an inwardly concave cavity 2 is processed on the side of the lower substrate 1 facing the upper substrate 5 by etching process. A plurality of hanging columns 4 are arranged at both ends of the cavity 2, wherein a gap is left between adjacent hanging columns 4 at the same end, wherein the size of the gap can pass through a group of fiber liquid-absorbing cores 7, and the specific setting of the size is determined according to the actual situation, and this application does not limit it;

[0043] Furthermore, a plurality of support columns 3 are arranged in a rectangular array in the cavity 2 of the lower substrate 1 and between the upper and lower hanging columns 4. It should be noted that the support columns 3 are used to support the lower substrate 1 and the upper substrate 5. When the upper and lower substrates are connected and fixed, the upper and lower ends of the support columns 3 just abut against the upper and lower substrates.

[0044] Furthermore, the fiber absorbent core 7 can be but not limited to copper fiber, aluminum fiber, stainless steel fiber, etc. The fiber absorbent core 7 is a woven fiber belt made of a plurality of fibers; the fiber absorbent core 7 is surrounded by a plurality of hanging columns 4, and the whole is a winding structure (refer to Figure 3 ), the head end of the fiber liquid absorbent core 7 is fixed to the lower substrate 5 by resistance spot welding, then the fiber liquid absorbent core is tightened to be evenly arranged on the inner surface of the lower substrate 5, and the tail end of the fiber liquid absorbent core 7 is also fixed to the lower substrate 5 by resistance spot welding. Finally, the fiber liquid absorbent core is sintered under high temperature conditions to be firmly combined with the lower substrate 5.

[0045] Reference Figure 2 , Figure 4 and Figure 5 A circle of bosses 6 are installed on one side where the upper substrate 5 is connected to the lower substrate 1, wherein the size of the bosses 6 just corresponds to the size of the cavity 2 on the lower substrate 1, so that the bosses 6 can just fit into the cavity 2, thereby realizing the snap-fit ​​fixation of the upper substrate 5 and the lower substrate 1.

[0046] The specific operating principles of this application are as follows:

[0047] S1. Substrate structure processing

[0048] A copper substrate with a size of 80×50×0.4 mm was taken, and a cavity 2, a hanging column 4 and a support column 3 structure were processed on one side of the substrate by an etching process. The size of the cavity 2 was 76×46×0.3 mm, and the size of the hanging column 4 was 4×1×0.3 mm. The hanging column 4 was set at a distance of 0.4 mm from the long side of the substrate cavity 2 and arranged in an array on both sides of the long side. The diameter of the support column 3 was 2 mm and the height was 0.3 mm. The support column 3 was arranged in an array on the surface of the cavity 2 to prepare a lower substrate 1 (such as Figure 1 shown);

[0049] Take a copper substrate of 80×50×0.25 mm, and use an etching process to process a 0.4 mm wide and 0.15 mm high surface on one side of the substrate. The outer circle size is 0.05-0.1 mm smaller than the outer circle size of the cavity 2 of the lower substrate 1, and the upper substrate 5 (such as Figure 2 shown);

[0050] It should be noted that the processing method can be but not limited to micro-milling process and etching process, etc.; and the size of each of the above structures needs to be determined according to the actual situation on site, and this application does not limit it, and only provides one preferred embodiment;

[0051] S2. Preparation of liquid wick structure

[0052] Take a copper braided fiber belt with a cross-sectional size of 0.4×0.15mm, arrange it on the cavity 2 of the lower substrate 1, and wrap it around the hanging column 4 structure on the lower substrate 1. The two ends of the tail are fixed by resistance spot welding. The welding method can be but not limited to diffusion welding, brazing, etc.; the copper braided fiber belt is tightened and arranged on the cavity 2 of the lower substrate 1, wherein the resistance spot welding current is 3.4A and the over-current time is 200ms. Then, it is pressed into a high-temperature heating furnace through a mold, heated to 750-950℃ for sintering connection. After sintering, remove the mold to obtain a lower substrate 1 with a liquid wick structure (such as Figure 3 shown);

[0053] It should be noted that the fiber absorbent core can be but not limited to copper fiber, aluminum fiber, stainless steel fiber, etc. The size of the copper braided fiber belt needs to be determined according to the actual situation on site. This application does not limit it, and only gives one preferred embodiment;

[0054] S3, Vapor Chamber Packaging

[0055] Take the prepared upper substrate 5, coat the outer ring of the boss 6 of the upper substrate 5 and the outer ring of the boss 6 along the plane of the upper substrate 5 with solder, insert it into the lower substrate with the prepared liquid wick structure, and after the upper and lower substrates are spliced, put them into a heating furnace and heat them to the melting point of the solder for welding, and then perform a series of processes such as vacuuming, pouring liquid working medium and sealing to prepare a heat spreader;

[0056] It should be noted that the welding method may be but not limited to diffusion welding, brazing, etc.; the injected phase change endothermic working fluid may be but not limited to deionized water, refrigerant, ethanol, etc.

[0057] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fiber wick ultra-thin heat spreader, comprising two sets of upper and lower substrates, characterized in that: A hanging column (4) is installed on one of the base plates, and the hanging column (4) is installed at two ends of the base plate, and there is a gap between two adjacent hanging columns (4) located at the same end; It also includes a fiber liquid-absorbing core (7), which can be wound around the hanging columns (4) at both ends in sequence and tightened to form a winding shape. Another base plate fixes the fiber liquid-absorbing core (7) fastened to the hanging column (4) between the two base plates.

2. The ultra-thin fiber wick vapor chamber according to claim 1, characterized in that: The fiber absorbent core (7) may be selected from, but not limited to, a copper fiber absorbent core, an aluminum fiber absorbent core, and a stainless steel fiber absorbent core.

3. The ultra-thin fiber wick heat sink according to claim 2, characterized in that: The fiber liquid-absorbing core (7) is a woven fiber belt formed by a plurality of fibers.

4. The ultra-thin fiber wick vapor chamber according to claim 1, characterized in that: A plurality of support columns (3) are provided on the substrate and between the two end hanging columns (4), and the other ends of the support columns (3) abut against another substrate.

5. The ultra-thin fiber wick vapor chamber according to claim 1, characterized in that: The substrate comprises a lower substrate (1) and an upper substrate (5); the hanging column (4) and the fiber liquid-absorbing core (7) are installed in a cavity (2) embedded in the lower substrate (1); and a circle of bosses (6) cooperating with the cavity (2) is provided on the side of the upper substrate (5) facing the lower substrate (1).

6. A method for preparing an ultra-thin heat spreader of a fiber liquid wick according to any one of claims 1 to 5, characterized in that: The steps include: S1. Preparation of heat spreader substrate: An inner cavity, supporting columns and hanging columns are processed on a metal substrate to obtain a lower substrate; A boss is machined on another metal base plate of the same size to obtain an upper base; S2. Installation of fiber absorbent core structure: The fiber liquid-absorbing core surrounds the hanging column in the inner cavity of the lower base plate; The head end of the fiber liquid-absorbing core is fixed on the lower base plate by resistance spot welding; Then, the fiber absorbent core is tightened to be evenly arranged on the inner surface of the lower substrate, and the tail end is fixed by resistance spot welding, and the fiber absorbent core is sintered at a high temperature to be fastened to the lower substrate; S3, heat sink package: The prepared lower substrate with a fiber wick structure is spliced ​​with the upper substrate, the base surfaces of the upper and lower substrates are welded and sealed, and then vacuuming, pouring phase change heat transfer medium and sealing are performed to prepare a heat spreader.

7. The method for preparing an ultra-thin heat spreader of a fiber liquid wick according to claim 6, characterized in that: The welding method in step S3 is but not limited to diffusion welding and brazing.

8. The method for preparing an ultra-thin heat spreader of a fiber liquid wick according to claim 6, characterized in that: The phase change heat transfer medium injected in step S3 may be, but is not limited to, deionized water, refrigerant and ethanol.

9. The method for preparing an ultra-thin heat spreader of a fiber liquid wick according to claim 6, characterized in that: The resistance spot welding current in step S2 is 3.4A, and the over-current time is 200ms.

10. The method for preparing an ultra-thin vapor chamber of a fiber wick according to claim 6, characterized in that: The temperature of high-temperature sintering of the fiber liquid-absorbing core in step S2 is 750-950°C.

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