Loop type vapor chamber and manufacturing method

Abstract

The invention provides a loop type vapor chamber and a manufacturing method, the loop type vapor chamber comprises a shell composed of a cover plate and a bottom plate, a condensation end with two symmetrical ends comprises an annular channel, the annular channel sequentially comprises a steam discharge channel, a steam heat dissipation channel and a liquid backflow channel, the annular channel is communicated with an evaporation end, and a part enclosed by the annular channel is a hollow part; the steam heat dissipation channel is provided with heat dissipation fins, and a centrifugal fan for providing air speed is arranged at the hollowed-out position. The liquid absorption core structure in the evaporation end comprises a first plane silk screen; the wick structure further comprises a spiral woven mesh, the spiral woven mesh penetrates through the steam heat dissipation channel and the liquid backflow channel of the condensation end, and the spiral woven mesh in the evaporation end surrounds a first plane silk screen and a second plane silk screen sintered with the cover plate. The supporting columns are used for supporting the spiral woven mesh and the first plane silk screen. The heat conduction coefficient is high, the heat resistance is small, and the heat of the chip can be guided to the heat dissipation fins in a short time for heat dissipation.

Description

Technical Field

[0001] The present invention relates to the field of chip heat dissipation, and in particular to a loop-type heat spreader and a manufacturing method thereof. Background Art

[0002] With the rapid development of the Internet industry, the power of chips in laptops and other communication equipment has increased, resulting in a larger heat flux density in the chips when laptops and other communication equipment are running, causing the chip temperature to be too high, resulting in loss of frequency and overclocking.

[0003] Traditional laptops and other communication devices use multiple flattened heat pipes to dissipate heat from chips through a segmented composite liquid wick structure, but the performance improvement space of this cooling solution has gradually reached its ceiling. Heat pipes are limited by the manufacturing process of the tubular structure and it is difficult to fundamentally solve the problem of limited fluid reflux. Therefore, it is important to develop a high-performance loop-type heat spreader. Summary of the invention

[0004] In order to improve multiple technical problems, the present invention provides a loop-type heat spreader and a manufacturing method. From the perspective of high-power chip heat dissipation, the high-performance loop-type heat spreader has high thermal conductivity and low thermal resistance. The heat of the chip can be transferred to the heat dissipation fins and dissipated in a short time, so that the high-power chip can meet the working range.

[0005] A loop-type heat spreader includes a shell composed of a cover plate and a bottom plate, the two symmetrical ends are condensing ends, and the middle connecting part is an evaporating end; the condensing end includes an annular channel, which includes a steam discharge channel, a steam heat dissipation channel and a liquid reflux channel in sequence, the annular channel is connected to the evaporating end, and the part surrounded by the annular channel is a hollow part; the steam heat dissipation channel is provided with heat dissipation fins, and the hollow part is provided with a centrifugal fan to provide wind speed;

[0006] A liquid wick structure is provided in the shell;

[0007] The liquid wick structure inside the evaporation end includes a first plane screen; the liquid wick structure also includes a spiral woven screen, the spiral woven screen runs through the steam heat dissipation channel and the liquid reflux channel of the condensation end, the spiral woven screen inside the evaporation end surrounds the first plane screen, and in addition, there is a second plane screen welded to the cover plate;

[0008] It also includes a support column, which is arranged at the steam heat dissipation channel of the evaporation end and the condensation end and is used to support the spiral woven mesh and the first plane wire mesh;

[0009] The three-dimensional phase change structure of the heat spreader adopts the symmetrical characteristics of the overall evaporation structure. Deionized water is contained in the heat spreader. When the evaporation end is heated, the internal working fluid absorbs heat and vaporizes from liquid to gas. Under the action of pressure, the gas flows to the annular channel and first enters the steam heat dissipation channel through the steam exhaust channel. At the hollow part, the cooling fins and the air are forced to exchange heat through air convection under the action of the centrifugal fan, thereby reducing the temperature of the heat spreader. At this time, the gas releases heat and liquefies into liquid. The liquid flows to the spiral woven mesh through the liquid reflux channel, and under the action of the capillary force of the spiral woven mesh, it flows back to the spiral woven mesh inside the evaporation end. Then, under the action of the penetration force, the liquid penetrates from the spiral woven mesh toward the first plane screen, thereby forming a gas-liquid circulation.

[0010] The volume ratio of the gas channel to the liquid channel in the evaporation end (302) is 1:2; and the height ratio of the gas channel to the liquid channel at the interface of the condensation end (301) is 1:2.

[0011] The first plane screen adopts a two-layer screen structure of 200 meshes + 100 meshes.

[0012] The spacing between the support columns at the evaporation end relative to the heat source is 7mm, and the spacing between the support columns at the position without the heat source is 10mm; the spacing between the support columns at the condensation end is 10mm.

[0013] The spiral woven mesh changes from a thin and tall type to a wide and short type at the interface between the steam heat dissipation channel and the liquid return channel.

[0014] The thickness of the cover plate and the bottom plate are both 0.4 mm.

[0015] The thickness of the entire heat spreader is 1 mm.

[0016] The manufacturing method of the loop-type vapor chamber comprises the following steps:

[0017] a) Processing cover plate, base plate and heat dissipation fins;

[0018] b) annealing the spiral woven mesh and cooling it to room temperature;

[0019] c) placing the support column in the graphite mold, placing the spiral woven mesh in the groove of the graphite mold, placing the first plane wire mesh on the bottom plate, and buckling the bottom plate on the graphite mold;

[0020] d) placing the bottom plate, the first flat screen, the spiral woven screen, the graphite mold and the support column as a whole in a multifunctional sintering furnace under a pressure of 20 MPa for sintering; the cover plate is directly sintered with the second flat screen;

[0021] e) placing the bottom plate, the first plane screen, the spiral woven screen and the support column as a whole after sintering in an annealing furnace for annealing, and measuring the saturated water absorption after cooling to room temperature;

[0022] f) The bottom plate, the first flat screen, the spiral woven screen and the support column are sintered together with the cover plate by riveting them together under a riveting fixture, and then placed in a diffusion welding furnace and welded together;

[0023] g) After the soaking plate is annealed, the first vacuuming process is performed to make the vacuum degree inside the soaking plate reach 30Pa~40Pa;

[0024] h) The second degassing process uses a 120°C baking pan to heat the vapor chamber, so that the non-condensable gas inside the vapor chamber gathers in the injection tube. The injection tube is precisely cut to further reduce the non-condensable gas inside the vapor chamber, so that the vacuum inside the vapor chamber reaches 0.01Pa to 0.001Pa;

[0025] i) Perform sealing welding on the cut position of the injection tube connected to the soaking plate;

[0026] j) The heat spreader is welded to the heat sink fins, and the centrifugal fan is installed in the hollow space.

[0027] The invention provides a loop-type heat spreader, which can be used for heat dissipation of high-power electronic chips and is installed through a thermally conductive gasket.

[0028] The high-power heating chip generates heat, which is transferred to the evaporation end of the high-performance loop-type heat spreader by heat conduction. The heated liquid at the evaporation end vaporizes and absorbs heat, and the gas flows to the condensation end through the gas channel. The gas at the condensation end releases heat and liquefies into liquid. The liquid flows into the spiral woven mesh with high capillary force, and flows into the evaporation end of the heat spreader under the action of capillary force. The heat released by the liquefaction of gas into liquid at the condensation end is transferred to the heat dissipation fins. The heat dissipation fins perform forced convection heat exchange with the air under the action of the fan, and bring the heat to the outside atmosphere through the air.

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

[0030] The present invention provides a loop-type vapor chamber. Compared with the existing technology, the vapor chamber and the heat dissipation system have the following advantages:

[0031] (1) The design of the high-performance loop-type heat spreader increases the power of the heat spreader and reduces the thermal resistance of the heat spreader. Traditional notebooks and other communication devices mostly use a structure in which multiple flattened heat pipes are welded together. Due to the walls of the multiple heat pipes, it is impossible to exchange gas and liquid channels between the heat pipes, so its maximum power is limited and the thermal resistance is relatively high. This design of the high-performance loop-type heat spreader solves this drawback, thereby increasing the power of the heat spreader and reducing the thermal resistance.

[0032] (2) High-performance loop-type heat spreaders use and design loop-type gas-liquid channels. This heat dissipation channel has a positive feedback gas-liquid phase change channel design, which ensures high power and low thermal resistance performance. In addition, it can also realize the design and manufacture of complex and special-shaped heat spreaders, and has a relatively wide range of applications.

[0033] (3) The traditional laptop cooling system requires a copper heat sink due to the existence of multiple heat pipes on the outer wall. The heat generated by the chip is transferred to the copper heat sink through heat conduction. The copper heat sink plays a role in equalizing the heat and transfers it to the heat pipe. The heat sink is welded to the heat pipe and forced convection heat exchange with the air is carried out to bring the heat into the external environment. The heat spreader used in this cooling system has a thermal conductivity coefficient of dozens of times that of the copper heat sink, and the copper heat sink is omitted. The heat generated by the chip is directly transferred to the high-performance loop-type heat spreader, reducing the thermal resistance of the entire cooling system and greatly improving the overall heat dissipation performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the bottom plate and liquid wick structure of the heat spreader and the gas-liquid phase change flow channel provided in the embodiment of the present invention.

[0035] Figure 2 It is an overall exploded schematic diagram of a heat spreader and a heat dissipation system provided in an embodiment of the present invention.

[0036] Figure 3 It is an exploded schematic diagram of a heat spreader provided in an embodiment of the present invention.

[0037] Figure 4 It is a schematic diagram of an explosion of a heat dissipation system provided in an embodiment of the present invention.

[0038] Figure 5 It is a schematic diagram of the evaporation end and condensation end areas of the heat spreader provided in the embodiment of the present invention.

[0039] Figure 6 It is a schematic diagram of the heat source position of the embodiment provided by the present invention.

[0040] Figure 7 It is a schematic diagram of the plane shape of the spiral woven mesh according to the embodiment of the present invention.

[0041] Figure 8 yes Figure 7 Schematic cross-section of .

[0042] Fig. 9 It is a schematic diagram of the gas-liquid phase change inside the evaporation end of the heat spreader of the embodiment provided by the present invention.

[0043] Fig.10 It is a three-dimensional schematic diagram of the welded mesh graphite mold provided by the present invention. DETAILED DESCRIPTION

[0044] The present invention is described in detail below in conjunction with the embodiments and drawings, but it should be understood that the embodiments and drawings are only used to exemplify the present invention and do not constitute any limitation on the protection scope of the present invention. All reasonable changes and combinations within the scope of the inventive concept of the present invention fall within the protection scope of the present invention.

[0045] like Figure 1 , Figure 2 and Figure 3 As shown, a loop type heat sink includes a shell consisting of a cover plate 201 and a bottom plate 203, such as Figure 5 The two symmetrical ends are condensation ends 301, and the middle connecting part is the evaporation end 302; the condensation end 301 includes an annular channel, which includes a steam discharge channel 108, a steam heat dissipation channel 103 and a liquid reflux channel 105 in sequence, and the annular channel is connected to the evaporation end 302, and the part surrounded by the annular channel is a hollow part 104; Figure 4 , the steam heat dissipation channel 103 is provided with heat dissipation fins 204, and the hollow part 104 is provided with a centrifugal fan 205 for providing wind speed;

[0046] A liquid wick structure is provided in the shell;

[0047] The liquid wick structure inside the evaporation end 302 includes a first plane screen 101; the liquid wick structure also includes a spiral woven mesh 106, the spiral woven mesh 106 runs through the steam heat dissipation channel 103 and the liquid return channel 105 of the condensation end 301, and the spiral woven mesh 106 in the evaporation end 302 surrounds the first plane screen 101, and there is also a second plane screen 202 welded to the cover plate 201;

[0048] It also includes a support column 102, which is arranged at the steam heat dissipation channel 103 of the evaporation end 302 and the condensation end 301, and is used to support the spiral woven mesh 106 and the first plane screen 101;

[0049] The liquid reflux channel 105 adopts a spiral woven mesh 106 (with strong axial capillary force) to solve the problem of difficult liquid reflux; the steam exhaust channel 108 only has supporting columns to increase the volume of the steam channel, reduce gas flow resistance, and reduce vapor-liquid friction; a flat wire mesh + liquid storage structure (spiral woven mesh) is adopted in the evaporation section 302 to solve the problem of difficult liquid reflux in the evaporation section to the greatest extent; the evaporation section 302 adopts a flat wire mesh structure (hydrophilic structure), and the condensation section 301 adopts a spaced columnar support structure (hydrophobic to a certain extent); further promoting liquid reflux.

[0050] The three-dimensional phase change structure of the vapor chamber adopts the overall evaporation structure symmetry characteristics, and the vapor chamber has deionized water working medium inside, such as Fig. 9The evaporation end 302 is heated, and the internal working fluid absorbs heat and vaporizes from liquid to gas. Under the action of pressure, the gas flows to the annular channel, first passes through the steam exhaust channel 108 and enters the steam heat dissipation channel 103. At the hollow part 104, the heat dissipation fins 204 and the air are forced to exchange heat by air convection under the action of the centrifugal fan 205, thereby reducing the temperature of the heat spreader. At this time, the gas releases heat and liquefies into liquid. The liquid flows to the spiral woven mesh 106 through the liquid reflux channel 105, and under the action of the capillary force of the spiral woven mesh 106, it flows back to the spiral woven mesh 106 in the evaporation end 302. Then, under the action of the penetration force, the liquid penetrates from the spiral woven mesh 106 toward the first plane screen 101, thereby forming a gas-liquid circulation.

[0051] The ratio of the gas channel to the liquid channel in the evaporation end 302 is 1:2; the ratio of the gas channel to the liquid channel at the interface of the condensation end 301 is 1:2.

[0052] The first planar screen 101 adopts a two-layer screen structure of 200 meshes + 100 meshes.

[0053] like Figure 6 At the condensation end 301, there is a steam heat dissipation channel 103 at the spiral woven net 106. In order to position and fix the spiral woven net, two rows of support columns 102 are placed to facilitate the welding of the spiral woven net 106 and the bottom plate 203. In order to ensure the strength and a larger gas channel, a row of support columns 102 are placed at the steam exhaust channel 108 without the spiral woven net. The spacing between the support columns 102 is 10mm; the spacing between the support columns 102 at the relative position 401 of the evaporation end 302 and the heat source is 7mm, and the spacing between the support columns 102 at the relative position 107 without the heat source is 10mm; the spacing between the support columns 102 at the condensation end 301 is 10mm. There are more support columns to increase the strength here and avoid collapse caused by contact with the chip.

[0054] like Figure 7 and Figure 8 The spiral woven mesh 106 changes from a thin and tall type to a wide and short type at the interface A between the steam heat dissipation channel 103 and the liquid reflux channel 105 .

[0055] The thickness of the cover plate 201 and the bottom plate 203 are both 0.4 mm

[0056] The thickness of the entire heat spreader is 1 mm.

[0057] The manufacturing method of the loop-type vapor chamber comprises the following steps:

[0058] a) Processing the cover plate 201, the bottom plate 203, and the heat dissipation fins;

[0059] b) annealing the spiral woven mesh and cooling it to room temperature;

[0060] c) Place the support column in the graphite mold and the spiral braided mesh in the Fig.10 In the graphite mold groove shown, the first plane screen 101 is fixed on the bottom plate 203, and the bottom plate 203 is buckled on the graphite mold;

[0061] d) placing the bottom plate 203, the first planar screen 101, the spiral woven screen 106, the graphite mold and the support column 102 as a whole in a multifunctional sintering furnace under a pressure of 20 MPa for sintering; the cover plate 201 is directly sintered with the second planar screen 202;

[0062] e) placing the bottom plate 203, the first planar screen 101, the spiral woven screen 106 and the support column 102 as a whole after sintering in an annealing furnace for annealing, and measuring the saturated water absorption after cooling to room temperature;

[0063] f) The bottom plate 203, the first planar wire mesh 101, the spiral woven mesh 106 and the support column 102 are sintered together with the cover plate 201 under a riveting fixture, and then placed in a diffusion welding furnace and welded together;

[0064] g) After the soaking plate is annealed, the first vacuuming process is performed to make the vacuum degree inside the soaking plate reach 30Pa~40Pa;

[0065] h) The second degassing process uses a 120°C baking pan to heat the vapor chamber, so that the non-condensable gas inside the vapor chamber gathers in the injection tube. The injection tube is precisely cut to further reduce the non-condensable gas inside the vapor chamber, so that the vacuum inside the vapor chamber reaches 0.01Pa to 0.001Pa;

[0066] i) Perform sealing welding on the cut position of the injection tube connected to the soaking plate;

[0067] j) The heat spreader and the heat sink fins 204 are welded, and the centrifugal fan 205 is installed in the hollow portion 104 .

[0068] A loop-type heat spreader provided by the present invention can be used for dissipating heat from high-power electronic chips. The heat is transferred to the evaporation end of the loop-type heat spreader by heat conduction. The heated liquid at the evaporation end 302 vaporizes and absorbs heat, and the gas flows to the condensation end 301 through the steam exhaust channel 108. The gas at the condensation end 301 releases heat and liquefies into liquid. The liquid flows into the spiral woven mesh 106 with high capillary force, and flows into the evaporation end 302 under the action of capillary force. The heat released by the liquefaction of gas into liquid at the condensation end 301 is transferred to the cooling fins 204. The cooling fins 204 perform forced convection heat exchange with the air under the action of the centrifugal fan 205, and bring the heat to the outside atmosphere through the air.

[0069] The high-performance loop-type heat spreader provided by the present invention is applied to notebook computers. Conventional notebook computers and other communication devices mostly adopt a structure in which a plurality of flattened heat pipes are welded together. Due to the walls of the multiple heat pipes, it is impossible to exchange gas and liquid channels between the heat pipes, so its maximum power is limited and the thermal resistance is relatively high. In addition, the heat dissipation system of the conventional notebook computer is as follows: the heat generated by the chip is transferred to the copper heat sink by heat conduction, the copper heat sink plays a role of equalizing heat and transfers it to the heat pipe, the heat pipe is welded with heat dissipation fins, and forced convection heat exchange is performed with the air to bring the heat into the external environment. Since the heat of the chip needs to be transferred layer by layer to the heat dissipation fins, the thermal resistance is relatively high. Larger; the high-performance loop-type heat spreader and heat dissipation system of the present invention, the heat generated by the high-power chip of the notebook is transferred to the high-performance loop-type heat spreader by heat conduction, and then transferred to the cooling fins. Under the action of the fan, the cooling fins perform forced convection heat exchange with the air to transfer the heat to the outside. This heat spreader and heat dissipation system changes a plurality of flattened heat pipes and a copper heat sink heat spreader into a high-performance loop-type heat spreader. The heat generated by the high-power chip is directly transferred to the high-performance loop-type heat spreader, which solves the problem of heat transfer layer by layer and reduces thermal resistance. In addition, the thermal conductivity of the high-performance loop-type heat spreader is higher than that of the traditional plurality of flattened heat pipes, and the maximum power is also improved.

[0070] The above embodiments are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A loop type heat sink, characterized in that: The shell comprises a cover plate (201) and a bottom plate (203), the two symmetrical ends are condensation ends (301), and the middle connecting part is an evaporation end (302); the condensation end (301) comprises an annular channel, the annular channel comprises a steam discharge channel (108), a steam heat dissipation channel (103) and a liquid reflux channel (105) in sequence, the annular channel is connected to the evaporation end (302), and the part surrounded by the annular channel is a hollow part (104); the heat dissipation fins (204) are arranged outside the condensation end (301) of the heat spreader, and the hollow part (104) is provided with a centrifugal fan (205) for providing wind speed; A liquid wick structure is provided in the shell; The liquid wick structure inside the evaporation end (302) includes a first planar screen (101); the liquid wick structure also includes a spiral woven screen (106), the spiral woven screen (106) runs through the steam heat dissipation channel (103) and the liquid reflux channel (105) of the condensation end (301), the spiral woven screen (106) inside the evaporation end (302) surrounds the first planar screen (101), and further includes a second planar screen (202) welded to the cover plate (201); It also includes a support column (102), which is arranged at the steam heat dissipation channel (103) of the evaporation end (302) and the condensation end (301) and is used to support the spiral woven mesh (106) and the first plane wire mesh (101); The three-dimensional phase change structure of the heat spreader adopts the symmetrical characteristics of the overall evaporation structure. The heat spreader has deionized water as the working medium. The evaporation end (302) is heated, and the internal working medium absorbs heat and vaporizes from liquid to gas. Under the action of pressure, the gas flows to the annular channel, first passes through the steam exhaust channel (108) and enters the steam heat dissipation channel (103). At the hollow part (104), the heat dissipation fins (204) and the air are forced to exchange heat by air convection under the action of the centrifugal fan (205), thereby reducing the temperature of the heat spreader. At this time, the gas releases heat and liquefies into liquid. The liquid flows to the spiral woven mesh (106) through the liquid reflux channel (105), and under the action of the capillary force of the spiral woven mesh (106), it flows back to the spiral woven mesh (106) in the evaporation end (302). Then, under the action of the penetration force, the liquid penetrates from the spiral woven mesh (106) toward the first plane screen (101), thereby forming a gas-liquid cycle.

2. A loop-type vapor chamber according to claim 1, characterized in that: The volume ratio of the gas channel to the liquid channel in the evaporation end (302) is 1:2; and the height ratio of the gas channel to the liquid channel at the interface of the condensation end (301) is 1:

2.

3. The loop-type vapor chamber according to claim 1, characterized in that: The first planar screen (101) adopts a two-layer screen structure of 200 meshes + 100 meshes.

4. The loop-type vapor chamber according to claim 1, characterized in that: The spacing between the support columns (102) at the evaporation end (302) and the heat source relative position (401) is 7 mm, and the spacing between the support columns (102) at the non-heat source relative position (107) is 10 mm; the spacing between the support columns (102) at the condensation end (301) is 10 mm.

5. A loop type vapor chamber according to claim 1, characterized in that The spiral woven mesh (106) changes from a thin and tall type to a wide and short type at the interface (A) between the steam heat dissipation channel (103) and the liquid return channel (105).

6. The loop-type vapor chamber according to claim 1, characterized in that: The thickness of the cover plate (201) and the bottom plate (203) are both 0.4 mm.

7. The loop-type vapor chamber according to claim 1, characterized in that: The thickness of the entire heat spreader is 1 mm.

8. The method for manufacturing a loop-type vapor chamber according to any one of claims 1 to 7, characterized in that: Here are the steps: a) processing the cover plate (201), the bottom plate (203), and the heat dissipation fins; b) annealing the spiral woven mesh and cooling it to room temperature; c) placing the support column in the graphite mold, placing the spiral woven mesh in the groove of the graphite mold, fixing the first plane screen (101) on the bottom plate (203), and buckling the bottom plate (203) on the graphite mold; d) placing the bottom plate (203), the first planar wire mesh (101), the spiral woven mesh (106), the graphite mold and the support column (102) as a whole in a multifunctional sintering furnace under a pressure of 20 MPa for sintering; the cover plate (201) is directly sintered with the second planar wire mesh (202); e) placing the sintered bottom plate (203), the first planar wire mesh (101), the spiral woven mesh (106) and the support column (102) in an annealing furnace for annealing, and measuring the saturated water absorption after cooling to room temperature; f) the bottom plate (203), the first planar wire mesh (101), the spiral woven mesh (106) and the support column (102) are sintered together with the cover plate (201) by riveting them together under a riveting fixture, and then placed in a diffusion welding furnace and welded together; g) After the soaking plate is annealed, the first vacuuming process is performed to make the vacuum degree inside the soaking plate reach 30Pa~40Pa; h) The second degassing process uses a 120°C baking pan to heat the vapor chamber, so that the non-condensable gas inside the vapor chamber gathers in the injection tube. The injection tube is precisely cut to further reduce the non-condensable gas inside the vapor chamber, so that the vacuum inside the vapor chamber reaches 0.01Pa to 0.001Pa; i) Perform sealing welding on the cut position of the injection tube connected to the soaking plate; j) The heat spreader and the heat dissipation fins (204) are welded, and the centrifugal fan (205) is installed in the hollowed-out area (104).

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