TWM640806U - Flat-plate heat pipe and heat exchanger - Google Patents

Abstract

The invention discloses a flat heat pipe and a heat exchanger. The flat heat pipe includes an upper shell and a lower shell. The upper shell and the lower shell are closed and connected to form a flat shell with a sealed cavity filled with a Variable working quality; there is a capillary core in the flat shell, and the surface of the capillary core has a micro-nano structure. Through the arrangement of capillary cores with micronano structures on the surface, the flat heat pipe of this invention has excellent thermal conductivity, strong anti-gravity ability, and flexible use and arrangement.

Description

Flat-plate heat pipes and heat exchangers

This creation is related to the technical field of two-dimensional fast heat conduction devices, in particular to a flat heat pipe and heat exchanger.

With the increasing development of science and technology, technologies in many cutting-edge fields have been popularized and improved, such as 5G communication, big data, cloud computing, AI and other new generation information and communication (ICT) technology performance has been rapidly improved; the rapid popularization of new energy vehicles, its power, Endurance performance is enhanced; high-energy cutting-edge equipment such as radar and laser instruments can be widely used. With the progress of these technologies, the devices are characterized by high integration and high energy density. Therefore, there must be problems of small and complicated heat dissipation space of the device, small heat dissipation area, and high heat flux density. Traditional air-cooled and liquid-cooled heat dissipation methods are difficult to meet the heat dissipation requirements of high heat flux density devices. The performance and reliability of these components generally decline sharply as the temperature rises, and the heat dissipation problem has become an important factor restricting the further development of a series of scientific and technological fields.

The working principle of the heat pipe is: in a vacuum state, when the evaporating section of the heat pipe is heated, the liquid in the evaporating section evaporates rapidly, and the steam flows to the condensing section under the action of the pressure difference, and after releasing heat, it condenses into a liquid again, and the liquid is absorbed by the suction. The capillary suction force of the liquid wick acts back to the evaporation section. The vapor gradually increases in the evaporating section and reaches the maximum at the edge of the evaporating section, then gradually decreases, and reaches the minimum at the end of the condensing section. The liquid is just the opposite, the most in the condensation section reaches the least in the evaporation section. Evaporation leads to the smallest radius of the meniscus formed by the surface tension of the evaporating section, and the largest capillary suction of the wick, while condensation causes the largest radius of the meniscus formed by the surface tension of the condensing section, and the smallest capillary suction of the wick.

The traditional heat pipe technology is based on the phase change heat transfer of the fluid working medium. Its application solves the problem of one-dimensional high heat flux and heat dissipation. The working principle of the vapor chamber is similar to that of the heat pipe, but it is different from the traditional heat pipe. The flat heat pipe (or vapor chamber ) is a two-dimensional heat conduction, which can transfer a concentrated point heat source to a larger area, and has a better heat transfer effect. However, the capillary core in the current vapor chamber is mostly a single structure, or simply combines several porous media as the capillary core, which has weak liquid absorption performance, which limits the return velocity of the phase change working fluid, and the heat transfer performance is limited. The above heat pipes with capillary core structure have poor anti-gravity ability, they fail when reverse gravity, and cannot transfer heat efficiently. In order to solve the problem of poor liquid absorption performance of a single capillary wick, patent application CN101848629A discloses a vapor chamber with a composite capillary structure of metal foam and copper powder. With the addition of copper powder, the porosity of the capillary core is greatly reduced, the flow and penetration resistance of the working fluid increases sharply, and the improvement of the overall capillary liquid absorption performance is limited, thus limiting its heat transfer efficiency.

This creation aims to solve at least one of the technical problems existing in the prior art. For this reason, this creation proposes a kind of flat heat pipe and heat exchanger.

The technical solutions adopted in this creation are:

The first aspect of the present invention provides a flat heat pipe, the flat heat pipe includes an upper shell and a lower shell, the upper shell and the lower shell are closed and connected to form a flat shell with a sealed cavity, so The sealed cavity is filled with a phase-change working medium; the flat shell is provided with a capillary core, and the surface of the capillary core has a first micronano structure.

The flat heat pipe of the embodiment of the invention has at least the following beneficial effects: the surface of the capillary core in the flat heat pipe has a first micronano structure, which can enhance the capillary driving effect on the phase change working fluid, improve the liquid absorption capacity of the capillary core, and improve the gas liquid circulation efficiency; in addition, through the first nanostructure setting on the surface of the capillary core, the phase transition can be strengthened to a certain extent in the heat exchange section of the flat heat pipe, improving Phase change efficiency, thereby improving the thermal conductivity and temperature uniformity of the flat heat pipe; and under the action of the above capillary core, the flat heat pipe is less affected by gravity when in use, has strong anti-gravity ability, and is flexible in use and arrangement.

According to some embodiments of the present invention, the capillary core includes a capillary core structure layer and/or a capillary chip layer; the capillary core structure layer is arranged on the inner wall of the flat shell, and the capillary chip layer is sandwiched between Between the upper casing and the lower casing; the surface of the capillary core structure layer and the surface of the capillary chip layer have the first micronano structure.

According to some embodiments of the present invention, the capillary core includes the capillary chip layer, and the inner wall of the flat shell has a second micronano structure.

According to some embodiments of the present invention, the flat shell includes a heat exchange section, the heat exchange section includes an evaporation section and a condensation section, and the evaporation section and the condensation section are sequentially distributed along the heat transfer direction of the flat heat pipe . According to some embodiments of the present invention, the capillary core includes the capillary chip layer, and the capillary chip layer is provided with a strip gap along the heat transfer direction of the flat heat pipe; the width of the strip gap is from the The thickness of the capillary core increases from the evaporation section to the condensation section of the flat shell, and/or the thickness of the capillary core increases from the evaporation section to the condensation section of the flat shell.

According to some embodiments of the present invention, the flat shell is a flexible flat shell; the capillary chip layer is sandwiched between the upper shell and the lower shell.

According to some embodiments of the present invention, the flat shell is a rigid flat shell, and a shell support is provided between the upper shell and the lower shell.

According to some embodiments of the present invention, the capillary core includes the capillary chip layer, and a capillary core support is also provided in the flat housing, and the capillary core support is used to press and fix the capillary chip layer on the inner wall surface of the flat shell.

The second aspect of the present invention provides a flat heat pipe, including an upper shell and a lower shell, the upper shell and the lower shell are closed and connected to form a flat shell with a sealed cavity, so The sealed cavity is filled with a phase-change working fluid; the flat shell is provided with a capillary core, and the inner surface of the flat shell has a second micronano structure.

The flat heat pipe of the embodiment of the invention has at least the following beneficial effects: the inner surface of the flat shell in the flat heat pipe has a second micronano structure, which can form an ultra-thin gas-liquid phase interface, form a phase change enhanced surface, and improve the phase change efficiency , and then improve the thermal conductivity and uniformity of the flat heat pipe.

According to some embodiments of the present creation, the capillary core includes a capillary core structure layer and/or a capillary chip layer; the capillary core structure layer is arranged on the inner wall surface of the flat shell, and the surface of the capillary core structure layer It has the second micronano structure; the capillary chip layer is sandwiched between the upper shell and the lower shell.

According to some embodiments of the present invention, the capillary core includes a capillary chip layer, and the surface of the capillary chip layer has a first micronano structure.

The third aspect of this creation provides any one of the flat heat pipe preparation methods provided by the first aspect of this creation, including the following steps: S1, preparing the upper shell and the lower shell to cooperate to form a flat shell; S2, in the A capillary core is arranged in the flat shell, and the surface of the capillary core is micronized so that the surface forms a first micronite structure; S3. The edges of the upper shell and the lower shell are sealed and connected to form There is a flat shell with a sealed cavity, and then the sealed cavity is evacuated and filled with phase change working fluid.

The preparation method of the flat heat pipe in the embodiment of the present invention has at least the following beneficial effects: in the preparation method, a capillary core is arranged in the flat shell, and the surface of the capillary core is treated with micronite, so that the surface of the capillary core forms a first micronite structure, It can enhance the capillary driving effect on the working medium, improve the liquid absorption capacity of the capillary wick, and improve the gas-liquid circulation efficiency; in addition, through the first micronose structure on the surface of the capillary wick, in the heat exchange section of the flat heat pipe, the phase can be strengthened. Change, improve the phase change efficiency, from The thermal conductivity and temperature uniformity of the flat heat pipe are improved, and the prepared flat heat pipe has strong anti-gravity ability and flexible use arrangement.

In step S2, the surface micro-nano treatment includes at least one of thermal oxidation treatment, electrochemical deposition, vapor phase physical deposition, femtosecond laser processing, and controlled sputtering.

The fourth aspect of this creation provides any one of the flat heat pipe preparation methods provided by the second aspect of this creation, including the following steps: S1, preparing the upper shell and the lower shell to cooperate to form a flat shell; S2, in the A capillary core is arranged in the flat shell, and the inner wall surface of the flat shell is subjected to surface micro-nano treatment, so that the surface forms a second micro-nano structure; S3, the edge of the upper shell and the lower shell Sealed connection is formed to form a flat shell with a sealed cavity, and then the sealed cavity is vacuumed and filled with phase change working fluid.

The preparation method of the flat heat pipe in the embodiment of the invention has at least the following beneficial effects: the preparation method conducts surface micronite treatment on the inner wall of the flat shell to form a second micronite structure on the surface, and can form a gas-liquid phase interface superstructure. Thinning, forming a phase change strengthened surface, improving the phase change efficiency, and then improving the thermal conductivity and uniformity of the flat heat pipe.

According to the fifth aspect of the present invention, there is provided a heat exchanger including any flat heat pipe provided in the first aspect or the second aspect of the present invention.

The heat exchanger of the embodiment of the invention has at least the following beneficial effects: the heat exchanger includes any flat heat pipe provided by the first aspect or the second aspect of the invention, based on the above beneficial effects of the flat heat pipe, the heat exchanger has High heat transfer performance.

10: flat shell

11: Upper shell

12: Lower shell

13: Shell support

14: capillary core support

15: The first nanostructure

16: Micro-channel capillary structure

17: capillary chip layer

18: Evaporation section

19: Condensation section

20: capillary core

21: Mounting through holes

30: Filling tube

Fig. 1 is a schematic structural view of a flat heat pipe of an embodiment of the invention; Fig. 2 is the SEM picture of the capillary chip layer in the flat heat pipe shown in Fig. 1; Fig. 3 is the partial schematic diagram of the cross section of the upper shell in the flat heat pipe of another embodiment of the invention along the direction perpendicular to the long axis of the flat heat pipe; Fig. 4 is Another embodiment of the invention is a schematic diagram of the nanostructure on the inner wall of the flat shell on the flat heat pipe; Figure 5 is a schematic diagram of the structure of the capillary chip layer on the flat heat pipe of another embodiment of the invention; Figure 6 is another embodiment of the invention flat heat pipe The structural representation of the upper capillary chip layer; Fig. 7 is the structural representation of the upper capillary chip layer of another embodiment of the flat heat pipe; Fig. 8 is a schematic cross-sectional view along the A-A line in Fig. 7; Fig. 9 is the liquid absorption performance of different capillary cores Test Results.

The following will clearly and completely describe the conception and technical effects of this creation in conjunction with the embodiments, so as to fully understand the purpose, characteristics and effects of this creation. Apparently, the described embodiments are only some of the embodiments of this creation, not all of them. Based on the embodiments of this creation, other embodiments obtained by those skilled in the art without any creative work belong to The scope of protection of this creation.

In the description of the embodiment of this invention, if it involves orientation descriptions, such as "upper", "lower", "front", "back", "left", "right" and other indicated orientations or positional relationships are based on the attached drawings The orientation or positional relationship shown is only for the convenience of describing the invention and simplifies the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a reference to the invention. limits.

In the description of the embodiment of this invention, if a feature is referred to as "setting", "fixing", "connecting", "installing" in another feature, it can directly set, fix, Connected to another feature can also be indirectly set, fixed, connected, mounted on another feature. In the description of the embodiment of this invention, if it involves "several", it means more than one; if it involves "multiple", it means more than two; if it involves "greater than", "less than", "more than ", should be understood as not including the original number, if it involves "above", "below", and "within", it should be understood as including the original number. If "first" and "second" are involved, it should be understood as used to distinguish technical features, and should not be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the indicated The sequence of technical features.

Please refer to FIG. 1 . FIG. 1 shows a schematic structural diagram of a flat heat pipe according to an embodiment of the invention. As shown in Figure 1, the flat heat pipe includes an upper shell 11 and a lower shell 12, the upper shell 11 and the lower shell 12 are closed and connected to form a flat shell 10 with a sealed cavity filled with phase change As for the working medium (not shown in the figure), a capillary core 20 is arranged inside the flat shell 10 , and the surface of the capillary core 20 has a first micronano structure 15 . The capillary core 20 covers the entire planar heat pipe. In this embodiment, the flat heat pipe further includes a liquid filling pipe 30 connected to the flat shell 10 and connected to the sealed cavity.

The tablet case 10 can be designed as a rigid planar case or a flexible planar case by using different materials according to the requirements of the application scene. Specifically, the material of the upper shell 11 and the lower shell 12 can be metal, including but not limited to copper, aluminum, aluminum alloy, steel and stainless steel, etc.; it can also be non-metallic, including but not limited to polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene (PE), polyethylene terephthalate (PET), glass, etc.; or composite materials, including but not limited to laminated composite materials (such as aluminum Plastic film, composite film of plastic and metal foil, etc.), doped composite materials (such as ceramic matrix composites, resin matrix composites, etc.). The material selection of the upper shell 11 and the lower shell 12 is determined according to the use requirements. For example, for high-power and high-temperature heat transfer scenarios, materials with good thermal conductivity (such as copper, aluminum, stainless steel, etc.) are required; Ultra-thin flexible material, so that the flat heat pipe can be bent and deformed, so that it can not only transfer heat on a plane with high performance, but also The heat transfer path is also more flexible, enabling heat transfer in curved paths. The flat shell 10 can be designed in different shapes according to actual application requirements, such as rectangle, square, trapezoid, circle, cylindrical shell, conical shell, etc., or be designed in a special-shaped configuration as required. The thickness of the flat shell 10 may be 0.05-100 mm. In this embodiment, the plate shell 10 is a rectangular rigid plate shell, the upper shell 11 and the lower shell 12 are made of aluminum alloy, and the heat transfer direction of the plate heat pipe is the long axis direction of the plate shell 10 .

The heat transfer direction of the flat heat pipe can be designed according to actual needs. For example, the flat heat pipe can be designed as a circular flat heat pipe, the flat shell is circular, the heat source can be arranged at the center of the circular flat heat pipe, and the heat transfer direction of the flat heat pipe is heat transfer from the center of the circle to the surrounding direction; or, the flat heat pipe A trapezoidal flat heat pipe can be designed, and its flat shell corresponds to a trapezoidal shape. The heat source can be set on the trapezoidal flat heat pipe close to the upper bottom side, and the heat transfer direction of the flat heat pipe is from the upper bottom to the lower bottom; or, the flat plate The heat pipe can be designed as a square flat heat pipe, and its flat shell is correspondingly square. The heat source can be arranged at the center of the square flat heat pipe, and the heat transfer direction of the flat heat pipe is from the center to the surrounding direction.

As shown in FIG. 1 , in this embodiment, the flat shell 10 is used as a protective shell, and the flat shell 10 is provided with a capillary core 20 , and the capillary core 20 is specifically sandwiched between the upper shell 11 and the lower shell 12 capillary chip layer 17, and the capillary chip layer 17 completely fills the inner plane of the entire flat shell 10. In this embodiment, the capillary chip layer 17 is made of metal foam, specifically copper foam, and the surface of the capillary chip layer 17 is treated with thermal oxidation micronite, so that the surface has a first micronano structure 15, the first micronano Structure 15 has superhydrophilic properties. Adopt scanning electron microscope to observe this capillary chip layer 17, the obtained result is shown in Figure 2, wherein, (a) is the SEM picture of capillary chip layer 17 in the flat heat pipe of the present embodiment, (b) is framed in (a) 3000x magnification of the area.

In other embodiments, other porous media materials can be used for the capillary core. For example, any one of wire mesh, sintered powder, and 3D printing materials can be used for low-temperature and normal-temperature applications. Ceramics, etc., and by surface micro-nano treatment The first micronano structure 15 is formed on the surface; the surface micronano treatment may specifically be thermal oxidation treatment, electrochemical deposition, vapor phase physical deposition, femtosecond laser processing, manipulated sputtering, and the like. By performing micro-nano treatment on the surface of the capillary chip layer 17, the first micro-nano structure 15 is formed on the surface, which can make it super-hydrophilic, enhance the capillary driving effect on the phase change working fluid, and improve the gas-liquid circulation efficiency.

In order to improve the stability of the heat pipe, in this embodiment, a shell support 13 is provided between the upper shell 11 and the lower shell 12, and the shell support 13 is specifically fixed on the inner surface of the lower shell 12. By setting The shell support 13 is used to support the flat shell 10 to prevent the inner cavity of the flat heat pipe from collapsing. In addition, in order to fix the capillary chip layer 17 , a capillary core support member 14 may also be provided in the flat shell 10 for pressing and fixing the capillary chip layer 17 on the inner wall of the flat shell 10 . In this embodiment, the capillary core supporting member 14 is also arranged on the inner surface of the lower housing 12 , specifically, the capillary chip layer 17 is pressed against the inner surface of the upper housing 11 by the capillary core supporting member 14 . In addition, in order to ensure the supporting effect of the housing support 13 and further ensure the installation stability of the capillary chip layer 17, the capillary chip layer 17 can be provided with an installation through hole 21 for installing the housing support 13, and the housing support 13 abuts against the upper case 11 through the installation through hole 21 of the capillary chip layer 17 for support. The shell supporting member 13 and the capillary core supporting member 14 can be designed in the shape of a cylinder, a square column, a prism, an elliptical column, and the like. If the flat shell 10 is a flexible flat shell, the above shell support 13 and capillary core support 14 may not be added.

In other embodiments, the capillary core structure layer can also be directly arranged on the inner wall of the flat shell 10, and the surface of the capillary core structure layer is treated with surface micronite (such as thermal oxidation treatment, electrochemical deposition, vapor phase physical deposition, Femtosecond laser processing, manipulation sputtering, etc.) to form a capillary core structure layer with a first micronano structure 15 on the inner wall of the flat shell 10, as a capillary core 20, which can penetrate the entire plane hot plate. Alternatively, a capillary core structure layer disposed on the inner wall of the flat shell 10 and having the first micronano structure 15 on the surface may be used, and a capillary core structure layer interposed between the upper shell 11 and the lower shell 12 and having the first micronano structure on the surface. The capillary chip layer 17 of the structure 15 is combined as the capillary core 20 , and the above capillary core structure layer and the capillary chip layer 17 are generally matched and connected to cover the entire planar heat pipe.

The basic structure of the capillary core structure layer on the inner wall of the flat shell 10 can adopt the basic structure similar to the capillary chip layer 17 above, or can be designed as a microchannel capillary structure 16 . If the basic structure of the capillary structure layer on the inner wall of the flat shell 10 adopts the micro-channel capillary structure 16, the micro-channel capillary structure 16 generally extends along the heat transfer direction of the corresponding flat heat pipe, and the micro-grooves on the inner wall of the flat shell 10 The capillary structure 16 can be designed in different shapes. For example, as shown in Fig. 3, Fig. 3 shows another embodiment of the present invention in the planar heat pipe of the upper casing along the direction perpendicular to the long axis of the plank shell section sectional schematic partial schematic diagram, specifically shown in Fig. 3 with different The micro-channel capillary structure 16 of micro-grooves, as shown in Figure 3 (a), is a square groove, (b) shows a triangular groove, (c) shows a circular groove, and (d) shows a trapezoidal groove . In addition, the micro-channel capillary structure 16 on the inner wall surface of the flat shell 10 can be arranged parallel and evenly along the heat transfer direction of the corresponding flat heat pipe; or, the width of the micro-channel capillary structure 16 can be unevenly arranged along the heat transfer direction of the corresponding flat heat pipe .

On the basis of the above basic structure of the capillary core structure layer, the surface is further subjected to surface micro-nano treatment, so that the surface has a first micro-nano structure 15 . The method of micronizing the surface of the inner wall of the flat shell 10 and the method of preparing the capillary chip layer 17 may be the same or different. As shown in Figure 4, in some embodiments, the surface micro-nano treatment can be carried out through the inner wall of the flat shell 10 to form a first micro-nano structure 15 of different shapes on the surface, for example, as shown in Figure 4 (a) Cylindrical array nanostructure shown in (b), elliptical cylindrical array microstructure shown in (b), circular platform array microstructure shown in (c), elliptical platform array microstructure shown in (d) , the cone array micronano structure shown in (e) and the square pyramid array micronano structure shown in (f). By providing the capillary structure layer on the inner wall surface of the flat shell 10 and performing surface micronization treatment, the gas-liquid phase transition interface can be ultra-thin and the phase transition strengthening surface can be formed, which can improve the phase transition efficiency.

In addition, in some embodiments, the capillary core 20 may include a capillary chip layer 17 interposed between the upper shell 11 and the lower shell 12 and having the first micronano structure 15 on the surface, and the inner wall surface of the flat shell 10 The area corresponding to the capillary chip layer 17 can also be subjected to surface micro-nano treatment to form the second micro-nano Chennai structure. For example, the capillary wick 20 is a capillary chip layer 17 covering the entire planar heat pipe and having a first micronano structure 15 on the surface, and the inner wall of the flat shell 10 can be treated with surface micronano to form a second micronano structure . Through the setting of the first micronanostructure 15 on the capillary chip layer 17 above, the liquid absorption capacity of the capillary core can be improved, and the gas-liquid circulation efficiency can be improved; through the setting of the second micronanostructure on the inner wall of the flat shell 10, the Strengthen the phase change and improve the efficiency of the phase change to improve the thermal conductivity and temperature uniformity of the flat heat pipe, and improve the anti-gravity ability of the flat heat pipe.

In some embodiments, the capillary core 20 in the flat shell 10 can also adopt a conventional or special capillary core, and the inner surface of the flat shell 10 (specifically, it can be the upper shell 11 and/or the lower shell 12) Surface micro-nano treatment to form a second micro-nano structure on the surface, that is, the inner surface of the flat shell 10 has a second micro-nano structure, so that the inner surface of the flat shell 10 can form a gas-liquid interface ultra-thin , to form a phase change strengthened surface, improve the phase change efficiency, and then improve the thermal conductivity and uniformity of the flat heat pipe. Generally, at least the inner surface of the heat exchange section of the flat shell is treated with surface micronite to strengthen the phase transformation. The capillary core 20 can specifically be a capillary core structure layer, a capillary chip layer 17 or a combination of the two, the capillary core structure layer is arranged on the inner wall surface of the flat shell 10, and the surface of the capillary core structure layer has a second micronose structure; The capillary chip layer 17 is interposed between the upper shell 11 and the lower shell 12 . The use of the capillary core structure layer with the second micronano structure can simultaneously strengthen the phase transition, improve the liquid absorption capacity of the capillary core, and improve the efficiency of gas-liquid circulation. In some embodiments, the capillary wick includes a capillary chip layer 17. In order to improve the liquid absorption capacity of the capillary wick, the surface of the capillary chip layer 17 can also be treated with surface micro-nano to form the first micro-nano structure 15, that is, the capillary chip. The surface of the layer 17 has a first nanostructure 15 .

In some embodiments, the capillary core 20 includes a capillary chip layer 17 sandwiched between the upper casing 11 and the lower casing 12, and a strip gap can be designed on the capillary chip layer 17 along the heat transfer direction of the flat heat pipe (such as As shown in Fig. 5, its heat transfer direction is the long axis direction of the flat shell), and the capillary chip layer 17 can be attached to the flat shell 10, so that the strip gap on the capillary chip layer 17 cooperates with the flat shell 10 The formed space acts as a sealed cavity or a part of the sealed cavity. According to the theory of multiphase fluid mechanics According to calculation, the gap ratio on the capillary chip layer 17 is generally designed to be 1-100. Through the design of the above structure, the capillary chip layer 17 can be used as a support between the upper case 11 and the lower case 12, eliminating the arrangement of additional supports or reinforcing ribs, and meeting the light and thin design requirements for devices.

Especially for the problem that many application scenarios need to export the heat of high heat flux devices in confined spaces and complex special-shaped spaces, the heat pipe is expected to have the characteristics of ultra-thin, flexible and deformable. However, the inside of the traditional vapor chamber or heat pipe requires additional space for the vapor cavity, and requires certain mechanical strength to maintain the shape of the cavity. Therefore, reinforcing ribs need to be arranged inside the existing vapor chamber or heat pipe, and the stamped shell has a large thickness and high rigidity, which makes it difficult to flexibly apply in confined spaces and complex special-shaped spaces, which restricts the heat dissipation of flat heat pipes in highly integrated and complex special-shaped devices. field applications.

For the special application occasions of the above limited space and complex space, in some embodiments of the present application, the flat heat pipe can be designed as an ultra-thin flexible flat heat pipe, specifically, a flexible flat shell can be used as the shell, and the capillary core 20 includes a bonding The flexible capillary chip layer 17 is sandwiched between the upper shell 11 and the lower shell 12, and can be combined with a graphic design and processing method to set a strip gap along the long axis direction of the flat shell 10 on the capillary chip layer 17, The space gap between the upper casing 11 and the lower casing 12 (comprising the space formed by the strip gap on the capillary chip layer 17 and the casing) is used as a closed cavity, so that there is no need to increase the additional cavity height in the thickness direction. The support of the capillary chip layer 17 does not require additional shell supports or ribs; and it can reduce the steam flow resistance and avoid the interference of gas-liquid rolling; at the same time, the capillary chip layer 17 has excellent flexibility, so that ultra-thin flexibility can be realized The preparation of the flat heat pipe can be in close contact with the device, can be used flexibly, improves its application range, and is suitable for heat dissipation of devices in complex systems with high integration and high power.

In some embodiments, the flat shell 10 may include a heat exchange section, the heat exchange section includes an evaporating section 18 and a condensing section 19 , and the evaporating section 18 and the condensing section 19 are sequentially distributed along the heat transfer direction of the flat heat pipe. In addition, in some embodiments, the flat shell 10 can also be designed to include a heat exchange section and a heat insulation section, the heat exchange section includes an evaporation section 18 and a condensation section 19, and the evaporation section 18, the insulation section and the condensation section 19 are arranged along the plate The heat transfer directions of the heat pipes are distributed sequentially. A capillary core structure layer with a micro-nano structure on the surface can be arranged on the inner wall of the heat exchange section of the flat shell 10, and a capillary chip layer 17 with a micro-nano structure on the surface can be arranged in the heat insulation section of the flat shell, and the capillary core structure layer and The capillary chip layer 17 is connected to cooperate with the capillary core 20 as a flat heat pipe to form a gas-liquid circulation system. By setting a capillary core structure layer with a micronano structure on the inner wall of the heat exchange section, an ultra-thin gas-liquid phase transition interface can be formed, a phase transition strengthening surface can be formed, the phase transition efficiency can be improved, and at the same time, it has a strong liquid absorption capacity; and By setting the capillary chip layer 17 with micro-nano structure on the surface in the thermal insulation section, due to the existence of the micro-nano structure on the surface, it has super-hydrophilic properties, so that the capillary chip layer 17 greatly enhances the penetration resistance without changing much. With the capillary driving effect of the phase change working medium, the gas-liquid circulation efficiency is significantly improved, and the thermal conductivity and temperature uniformity of the flat heat pipe are also significantly enhanced, and under the action of the capillary core 20 above, the flat heat pipe uses is minimally affected by gravity.

The shape of the capillary core 20 can be designed differently according to different application scenarios, specifically, it can be designed to be of equal thickness, or designed so that the thickness of the capillary core 20 is unequal (as shown in FIGS. 7 and 8 ). The shape of the capillary wick 20 can be designed to gradually increase from the evaporating section 18 to the condensing section 19 of the flat shell 10 according to the application requirements, that is, the thickness of the capillary wick increases progressively from the evaporating section 18 to the condensing section 19 of the flat shell 10, and the capillary The cross-section of the core 20 increases continuously along the direction perpendicular to the long axis of the flat shell 10, and the outer surface of the capillary core 20 forms a certain angle with the inner wall surface of the upper shell 11 of the flat shell 10, such as 0.5-5°. This range can be exceeded under certain conditions. When the heat pipe is working, generally the evaporating section 18 has the largest amount of vapor and the least amount of liquid, while the condensing section 19 has the smallest amount of vapor and the most liquid; and due to the influence of surface tension and the interaction between the gas-liquid interface, the gas-liquid interface of the evaporating section 18 is depressed in the capillary The surface of the wick 20 forms a very small contact angle, resulting in the largest capillary suction force of the capillary wick 20, while in the condensation section 19, the gas and liquid spread flat on the surface of the capillary wick 20, forming a larger contact angle, resulting in the capillary suction of the capillary wick 20. minimum force; through the structural design of the capillary wick 20 above, thin capillary The thick capillary wick structure is adopted in the condensing section 19 where there are many liquids and low capillary force, which can ensure the reflux of the liquid and smooth the steam flow path, thereby improving the capillary limit power of the heat pipe.

In addition, as shown in FIG. 5, in some embodiments, the width of the strip gap on the capillary chip layer 17 can also be set to be equal in width along the gas-liquid circulation direction (or the long axis direction of the flat shell 10). Or, as shown in Figure 6, according to the usage situation, the width of the strip gap is designed to be unequal, and it can be designed that the strip gap increases progressively from the evaporation section 18 to the condensation section 19 of the flat shell 10, so as to further improve the heat pipe. heat transfer efficiency. For example, for the circular parallel heat pipe that the heat transfer direction is transferred from the center to the surrounding direction, if its capillary chip layer 17 is correspondingly circular, the strip gap on its capillary chip layer 17 can be designed to be from the center of the capillary chip layer 17. Gradually increase around the perimeter. Or, for the trapezoidal flat heat pipe that the direction of heat transfer is transmitted from the upper base to the lower base, if its capillary chip layer 17 is correspondingly trapezoidal, the strip gap on its capillary chip layer 17 can be designed as from the capillary chip layer 17 The upper bottom edge gradually increases toward the lower bottom edge.

The phase-change working medium in the sealed cavity of the flat-plate housing 10 can be selected according to different application scenarios of the flat-plate heat pipe. For example, low-temperature phase change working fluids can be selected, including but not limited to helium, ammonia, nitrogen, pentane, Freon-21 (CHCI2F), Freon-11 (CCI3F) and Freon-113 (CCI2F.CCIF2); or , can choose normal temperature phase change working medium, including but not limited to deionized water after degassing treatment, acetone, methanol, heptane, ethanol or methanol, etc.; or, can choose high temperature phase change working medium, including but not limited to, potassium , Potassium salt, Lithium, Mercury, Cesium, Keng, etc. The ratio of the volume of the phase-change working fluid injected into the sealed cavity of the flat shell 10 to the volume of the sealed cavity can be set according to actual design requirements, and is generally 5% to 80%.

The surface of the capillary core 20 in the above flat heat pipe has a micro-nano structure, which can increase the capillary driving effect of the phase change working medium, improve the liquid absorption capacity of the capillary core 20, and improve the gas-liquid circulation efficiency; through the micro-nano structure on the surface of the capillary core 20 Setting, the phase change can be enhanced in the heat exchange section of the flat heat pipe, and the phase change efficiency can be improved, thereby improving the thermal conductivity and temperature uniformity of the flat heat pipe; Under the action of the capillary wick 20 of the Nai structure, the flat heat pipe is less affected by gravity during use and has a strong anti-gravity capability. According to infrared measurement, when the heating power of the flat heat pipe in this embodiment is 100W, the maximum temperature difference is less than 1°C, the temperature uniformity is excellent, and its effective thermal conductivity is 6.67×105W/(m.K), which is 1755 times that of copper. Excellent performance. And when the flat heat pipe is placed horizontally and vertically along the direction of gravity, the difference in effective thermal conductivity and heat transfer performance is very small. It is very good, indicating that the flat heat pipe can run against gravity, so that its use and arrangement are very flexible; and its processing is simple and low in cost.

The invention also provides a method for preparing more than one flat heat pipe, which may include the following steps:

S1. Prepare the upper case 11 and the lower case 12 to cooperate as the flat case 10 . For the rigid flat shell, the shell support 13 and/or the capillary support 14 can be arranged on the lower shell 12, and then can be cleaned with an organic cleaning solution (such as isopropanol or acetone, etc.) to remove the ester, and then dilute hydrochloric acid Clean the surface to remove the oxide layer. As for the flexible flat shell, the setting of the above supporting member can be cancelled.

S2 , setting capillary cores in the flat shell 10 , and performing micronano treatment on the surface of the capillary cores, so that the first micronanostructures 15 are formed on the surface. Specifically, the inner wall surface of the upper shell 11 and/or the lower shell 12 can be provided with a capillary core structure base layer, and the surface can be subjected to surface micro-nano treatment to form a capillary core structure layer with a first micro-nano structure 15 on the surface; and/ Or, use porous media materials to prepare the capillary core base layer, use organic cleaning liquids such as isopropanol or acetone to clean and remove the ester, and then wash the surface with dilute hydrochloric acid to remove the oxide layer, and then carry out surface micronization treatment on the capillary core base layer to form a surface with The capillary chip layer 17 of the first micronano structure 15 is sandwiched between the upper casing 11 and the lower casing 12 . In addition, for the case where the capillary core 20 includes the capillary chip layer 17, the surface micronization treatment can be performed on the inner wall surface of the flat shell on the area corresponding to the capillary chip layer 17 to form a second micronanostructure to enhance the phase transition.

Or, a capillary core is set in the flat shell 10, and the inner surface of the flat shell 10 is subjected to surface micro-nano treatment, so that the surface forms a second micro-nano structure; the capillary core 20 can be the above capillary core or a conventional capillary core, And generally at least the inner surface of the heat exchange section of the flat shell 10 is subjected to surface micronization treatment.

S3. The edges of the upper casing 11 and the lower casing 12 are sealed and connected to form a flat casing with a sealed cavity, and the sealed cavity is vacuumed and phase-change working fluid is poured into the sealed cavity. Among them, the sealing connection can be specifically welded, the vacuum range of the vacuum is generally 10-5~104Pa, and the volume ratio of the volume of the poured phase change working medium to the volume of the sealed cavity is generally 5%~80%.

In the above preparation method, a capillary core is set in the flat shell. If the capillary core is subjected to surface micro-nano treatment, the surface of the capillary core 20 has a first micro-nano structure 15, which can enhance the capillary driving effect on the working medium and improve the capillary core. The liquid absorption capacity improves the gas-liquid circulation efficiency; in addition, through the first micronano structure 15 on the surface of the capillary core, the phase change can be strengthened in the heat exchange section of the flat heat pipe, and the phase change efficiency can be improved, thereby improving the heat conduction of the flat heat pipe and temperature uniformity, the flat heat pipe made by it has strong anti-gravity ability and flexible use arrangement. If the surface micronite treatment is performed on the inner surface of the flat shell, the inner surface has a second micronano structure, which can also strengthen the phase transition and improve the phase transition efficiency.

The inventor carried out capillary wick liquid absorption performance experiments on the capillary wicks used in the flat heat pipe shown in Figure 1 in this creation and the different capillary wicks used in existing flat heat pipes, wherein the capillary wick used in the flat heat pipe shown in Figure 1 in this creation is used as an experimental example , which is the surface oxidation process modified copper foam super-hydrophilic micro-nano structure as the capillary chip layer 17; the capillary core of comparative example 1 is foamed nickel capillary chip layer 17; the capillary core in comparative example 2 and comparative example 4 has parallel Uniformly arranged square microchannel capillary structure 16, and capillary chip layer 17 of sintered porous particles in the microgroove; the capillary core of Comparative Example 3 is a capillary chip layer 17 in which copper particles are sintered into a foam shape. The liquid absorption properties of the above capillary cores were tested respectively, and the obtained results are shown in FIG. 9 . As can be seen from Fig. 9, the wool used in the above flat heat pipe of the present invention The surface of the thin chip layer 17 is treated with micronano to make the surface have the first micronano structure 15, and its liquid absorption height is significantly improved, which is 2 to 3 times that of the capillary core of the existing comparative example.

The above flat heat pipes can be further applied to the preparation of heat exchangers, therefore, this invention also improves a heat exchanger, including any of the above flat heat pipes. In addition, in order to enhance the heat exchange efficiency, according to the application requirements, heat exchange strengthening components (such as fins, water cooling blocks, radiation-enhancing coatings, etc.) Heat exchangers can be used in various heat dissipation or heating scenarios, including but not limited to base station chips, computer CPUs, automotive power batteries and fast charging, rapid preheating of automotive power batteries and power modules, efficient heat exchange for power generation devices, and laser , radar and other high heat flux heat dissipation.

10: flat shell

11: Upper shell

12: Lower shell

13: Shell support

14: capillary core support

20: capillary core

21: Mounting through holes

30: Filling tube

Claims (8)

A flat heat pipe, characterized in that: the flat heat pipe includes an upper shell and a lower shell, the upper shell and the lower shell are closed and connected to form a flat shell with a sealed cavity, and the sealed cavity It is filled with phase-change working fluid; a capillary core is arranged inside the flat shell, and the surface of the capillary core has a first micronano structure. The flat heat pipe as claimed in claim 1, wherein the capillary core comprises a capillary core structure layer and/or a capillary chip layer; the capillary core structure layer is arranged on the inner wall of the flat shell, and the capillary chip layer Interposed between the upper shell and the lower shell; the surface of the capillary core structure layer and the surface of the capillary chip layer have the first micronano structure. The flat heat pipe according to claim 2, wherein the capillary core includes the capillary chip layer, the inner wall surface of the flat shell has a second micro-nano structure, the flat shell includes a heat exchange section, and the heat exchanger The heat section includes an evaporating section and a condensing section, the evaporating section and the condensing section are distributed sequentially along the heat transfer direction of the flat heat pipe, the capillary core includes the capillary chip layer, and the capillary chip layer along the The heat transfer direction of the flat heat pipe is provided with a strip gap; the width of the strip gap increases from the evaporation section of the flat shell to the condensation section, and/or, the thickness of the capillary core increases from the thickness of the flat shell to the condensation section. The evaporating section to the condensing section increases incrementally. The flat heat pipe according to any one of claims 1 to 3, wherein the flat shell is a flexible flat shell; the capillary chip layer is sandwiched between the upper shell and the lower shell between. The flat heat pipe according to any one of claims 1 to 3, wherein the flat shell is a rigid flat shell, and a shell support is provided between the upper shell and the lower shell. The flat heat pipe according to claim 5, wherein the capillary core includes the capillary chip layer, and a capillary core support is also provided in the flat shell, and the capillary core support is used to support the capillary chip layer It is pressed and fixed on the inner wall surface of the flat shell. A flat heat pipe, characterized in that: the flat heat pipe includes an upper shell and a lower shell, the upper shell and the lower shell are closed and connected to form a flat shell with a sealed cavity, and the sealed cavity Filled with a phase change working fluid; the flat shell is provided with a capillary core, the inner surface of the flat shell has a second micronano structure, and the capillary core includes a capillary core structure layer and/or a capillary chip layer; the The capillary core structure layer is arranged on the inner wall surface of the flat shell, and the surface of the capillary core structure layer has the second micronano structure; the capillary chip layer is sandwiched between the upper shell and the lower shell. Between the shells, the capillary core includes a capillary chip layer, and the surface of the capillary chip layer has a first micronano structure. A heat exchanger, characterized in that it comprises the flat heat pipe according to any one of claims 1 to 6 or the flat heat pipe according to claim 7.

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