A loop-type heat spreader and its manufacturing method

Abstract

This invention provides a loop-type vapor chamber and its manufacturing method, comprising a shell composed of a cover plate and a base plate. The symmetrically positioned condensing ends include annular channels, which sequentially include a steam exhaust channel, a steam heat dissipation channel, and a liquid return channel. The annular channels communicate with the evaporating ends, and the portion enclosed by the annular channels is a perforated area. The steam heat dissipation channel is equipped with heat dissipation fins, and a centrifugal fan providing airflow is installed in the perforated area. The liquid-absorbing core structure inside the evaporating end includes a first planar wire mesh. The liquid-absorbing core structure also includes a spiral woven mesh, which penetrates the steam heat dissipation channel and the liquid return channel of the condensing end. Inside the evaporating end, the spiral woven mesh surrounds the first planar wire mesh and a second planar wire mesh sintered with the cover plate. Support columns support the spiral woven mesh and the first planar wire mesh. This invention has high thermal conductivity and low thermal resistance, enabling it to quickly transfer heat from the chip to the heat dissipation fins for heat dissipation.

Description

Technical Field

[0001] This invention relates to the field of chip heat dissipation, and more particularly to a loop-type heat sink and its manufacturing method. Background Technology

[0002] The rapid development of the Internet industry has led to an increase in the power of chips in laptops and other communication devices. This results in a higher heat flux density in the chips during operation, causing them to overheat and leading to issues such as frequency loss and overclocking.

[0003] Traditional laptops and other communication devices use multiple flattened heat pipes with a segmented composite wick structure to dissipate heat from the chip. However, the performance improvement potential of this cooling solution has gradually reached its limit. The heat pipes, limited by the manufacturing process of their tubular structure, cannot fundamentally solve the problem of restricted refrigerant reflux. Therefore, developing a high-performance loop-type vapor chamber has become a key focus. Summary of the Invention

[0004] To address several technical issues, this invention provides a loop-type heat sink and its manufacturing method. From the perspective of heat dissipation for high-power chips, the high-performance loop-type heat sink has a high thermal conductivity and low thermal resistance, which can transfer the heat from the chip to the heat sink fins and dissipate it in a short time, allowing the high-power chip to operate within its acceptable range.

[0005] A loop-type heat spreader includes a shell consisting of a cover plate and a base plate. The two ends are symmetrically arranged as condensing ends, and the middle connecting part is an evaporating end. The condensing end includes an annular channel, which sequentially includes a steam discharge channel, a steam heat dissipation channel, and a liquid return channel. The annular channel is connected to the evaporating end, and the part enclosed by the annular channel is a hollow area. The steam heat dissipation channel is provided with heat dissipation fins, and a centrifugal fan is provided in the hollow area to provide airflow.

[0006] The housing contains a liquid-absorbing core structure;

[0007] The liquid-absorbing core structure inside the evaporator includes a first planar wire mesh; the liquid-absorbing core structure also includes a spiral braided wire mesh, which runs through the vapor heat dissipation channel and the liquid return channel of the condenser end. The spiral braided wire mesh surrounds the first planar wire mesh inside the evaporator end. In addition, there is a second planar wire mesh welded to the cover plate.

[0008] It also includes support columns, which are located at the steam heat dissipation channels at the evaporation end and the condensation end, and are used to support the spiral woven mesh and the first planar wire mesh;

[0009] The three-dimensional phase change structure of the heat exchanger adopts the overall symmetrical evaporation structure. The heat exchanger contains deionized water as the working fluid. When the evaporation end is heated, the working fluid absorbs heat and vaporizes from liquid to gas. Under pressure, the gas flows into the annular channel. It first enters the steam heat dissipation channel through the steam exhaust channel. In the hollowed-out area, the heat dissipation fins and the air undergo forced air-cooled convection heat exchange under the action of a centrifugal fan, which lowers the temperature of the heat exchanger. At this time, the gas releases heat and liquefies into liquid. The liquid flows to the spiral braided mesh through the liquid return channel. Under the action of capillary force of the spiral braided mesh, it flows back to the spiral braided mesh in the evaporation end. Then, under the action of permeation force, the liquid permeates from the spiral braided mesh towards the first plane wire mesh, thus 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; 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 planar wire mesh adopts a two-layer wire mesh structure of 200 mesh + 100 mesh.

[0012] The spacing between the support columns at the evaporator end relative to the heat source is 7mm, and the spacing between the support columns at the non-heat source relative position is 10mm; the spacing between the support columns at the condenser end is 10mm.

[0013] The spiral woven mesh transitions 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 both the cover plate and the bottom plate is 0.4 mm.

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

[0016] The manufacturing method of the loop-type heat spreader includes the following steps:

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

[0018] b) The spiral braided mesh is annealed and cooled to room temperature;

[0019] c) Place the support column inside the graphite mold, place the spiral woven mesh inside the graphite mold groove, fix the first flat wire mesh on the base plate, and fasten the base plate to the graphite mold.

[0020] d) The base plate, the first planar wire mesh, the spiral woven mesh, the graphite mold, and the support column are placed together in a multi-functional sintering furnace and sintered under a pressure of 20 MPa; the cover plate is sintered directly with the second planar wire mesh.

[0021] e) The base plate, the first flat wire mesh, the spiral woven mesh and the support column, after being sintered, are placed in an annealing furnace for annealing. After cooling to room temperature, the saturated water absorption is measured.

[0022] f) The base plate, the first flat wire mesh, the spiral woven mesh and the support column, after sintering, are riveted together with the cover plate under the riveting fixture and then placed on the diffusion welding furnace to be welded together.

[0023] g) After the heat spreader is annealed, a first vacuum process is performed to make the vacuum degree inside the heat spreader reach 30Pa~40Pa.

[0024] h) The second degassing process involves heating the heat spreader plate at 120°C using a baking pan, causing non-condensable gases inside the heat spreader plate to accumulate in the injection pipe. By precisely cutting the injection pipe, the amount of non-condensable gases inside the heat spreader plate is further reduced, allowing the vacuum degree inside the heat spreader plate to reach 0.01Pa~0.001Pa.

[0025] i) Seal and weld the cut-off position of the injection pipe connected to the heat spreader.

[0026] j) The heat spreader and heat sink fins are welded together, and the centrifugal fan is installed in the perforated area.

[0027] The present invention provides a loop-type heat sink that can be used for heat dissipation of high-power electronic chips and is installed via thermal pads.

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

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

[0030] This invention provides a loop-type heat dissipation plate. Compared with existing technologies, this heat dissipation plate and system have the following advantages:

[0031] (1) The design of the high-performance loop type heat sink improves the power of the heat sink and reduces the thermal resistance of the heat sink. Traditional laptops and other communication devices mostly use a structure of multiple flattened heat pipes welded together. Due to the multiple heat pipe walls, gas-liquid channels cannot be exchanged between the heat pipes, so the power limit is limited and the thermal resistance is relatively high. This high-performance loop type heat sink design solves this drawback, improving the power of the heat sink and reducing the thermal resistance.

[0032] (2) The high-performance loop-type heat sink adopts and designs a loop-type gas-liquid channel. 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 irregular heat sinks, and has a wide range of applications.

[0033] (3) Traditional laptop cooling systems require copper heat sinks due to the presence 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 heat equalization and transfers the heat to the heat pipes. Heat dissipation fins are welded on the heat pipes and forced convection heat exchange with the air to carry the heat into the external environment. However, the heat dissipation system uses a heat spreader with a thermal conductivity that is tens of times that of the copper heat sink and eliminates the need for a copper heat sink. 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. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the base plate and liquid absorption core structure of the heat spreader provided in the embodiment of the present invention, as well as the gas-liquid phase change flow channel.

[0035] Figure 2 This is an exploded view of the heat spreader and heat dissipation system provided in the embodiments of the present invention.

[0036] Figure 3 This is an exploded view of the heat spreader provided in the embodiment of the present invention.

[0037] Figure 4 This is an exploded view of the heat dissipation system provided in an embodiment of the present invention.

[0038] Figure 5 This is a schematic diagram of the evaporation and condensation areas of the heat spreader plate in an embodiment provided by the present invention.

[0039] Figure 6 This is a schematic diagram of the heat source location in an embodiment provided by the present invention.

[0040] Figure 7 This is a schematic diagram of the planar shape of the spiral woven mesh provided in the embodiment of the present invention.

[0041] Figure 8 yes Figure 7 A cross-sectional schematic diagram.

[0042] Figure 9 This is a schematic diagram of the gas-liquid phase change inside the evaporator end of the heat spreader provided in the embodiment of the present invention.

[0043] Figure 10 This is a three-dimensional schematic diagram of the graphite mold for welding wire mesh provided by the present invention. Detailed Implementation

[0044] The present invention will now be described in detail with reference to embodiments and accompanying drawings. However, it should be understood that the embodiments and drawings are for illustrative purposes only and do not constitute any limitation on the scope of protection of the present invention. All reasonable modifications and combinations included within the inventive spirit of the present invention fall within the scope of protection of the present invention.

[0045] like Figure 1 , Figure 2 and Figure 3 As shown, a loop-type heat spreader includes a shell composed of a cover plate 201 and a bottom plate 203, as... Figure 5 The two ends are symmetrically connected as condenser end 301, and the middle connecting part is evaporator end 302; condenser end 301 includes an annular channel, which sequentially includes a steam discharge channel 108, a steam heat dissipation channel 103, and a liquid return channel 105. The annular channel is connected to evaporator end 302, and the part enclosed by the annular channel is the hollow section 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 to provide airflow.

[0046] The housing contains a liquid-absorbing core structure;

[0047] The liquid-absorbing core structure inside the evaporation end 302 includes a first planar wire mesh 101; the liquid-absorbing core structure also includes a spiral braided mesh 106, which penetrates the vapor heat dissipation channel 103 and the liquid return channel 105 of the condensation end 301. The spiral braided mesh 106 surrounds the first planar wire mesh 101 inside the evaporation end 302. In addition, there is a second planar wire mesh 202 welded to the cover plate 201.

[0048] It also includes a support column 102, which is located at the steam heat dissipation channel 103 between the evaporation end 302 and the condensation end 301, and is used to support the spiral woven mesh 106 and the first planar wire mesh 101.

[0049] The liquid reflux channel 105 uses a spiral braided mesh 106 (with high axial capillary force) to solve the problem of difficult liquid reflux; the steam discharge channel 108 only has supporting columns, which increases the volume of the steam channel, reduces gas flow resistance, and reduces vapor-liquid friction; the evaporation section 302 uses a planar wire mesh + liquid storage structure (spiral braided mesh) to solve the problem of difficult liquid reflux in the evaporation section to the greatest extent; the evaporation section 302 uses a planar wire mesh structure (hydrophilic structure), and the condensation section 301 uses an intermittent columnar support structure (to a certain extent hydrophobic); further promoting liquid reflux.

[0050] The three-dimensional phase change structure of the heat spreader adopts the overall symmetrical evaporation structure, and the heat spreader contains deionized water as a working fluid, such as... Figure 9When the evaporator end 302 is heated, the internal working fluid absorbs heat and vaporizes from liquid to gas. Under pressure, the gas flows into the annular channel, first passing through the steam discharge channel 108 and entering the steam heat dissipation channel 103. At the hollow part 104, under the action of the centrifugal fan 205, the heat dissipation fins 204 and the air undergo forced air-cooled convection heat exchange, which reduces the temperature of the heat spreader. At this time, the gas releases heat and liquefies into liquid. The liquid flows through the liquid return channel 105 to the spiral braided mesh 106. Under the action of the capillary force of the spiral braided mesh 106, it flows back to the spiral braided mesh 106 in the evaporator end 302. Then, under the action of the permeation force, the liquid permeates from the spiral braided mesh 106 towards the first planar wire mesh 101, thus forming a gas-liquid circulation.

[0051] The ratio of gas channels to liquid channels in the evaporator end 302 is 1:2; the ratio of gas channels to liquid channels at the interface of the condenser end 301 is 1:2.

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

[0053] like Figure 6 At the condensing end 301, two rows of support columns 102 are placed in the steam heat dissipation channel 103 at the location of the spiral braided mesh 106 to position and fix the spiral braided mesh, facilitating welding of the spiral braided mesh 106 to the base plate 203. At the steam exhaust channel 108 without the spiral braided mesh, a row of support columns 102 is placed to ensure strength and a larger gas passage. The spacing between the support columns 102 is 10mm. At the position 401 relative to the heat source at the evaporating end 302, the spacing between the support columns 102 is 7mm; at the position 107 without the heat source, the spacing between the support columns 102 is 10mm; and at the condensing end 301, the spacing between the support columns 102 is 10mm. The large number of support columns increases the strength at this location and prevents collapse due to 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 return channel 105.

[0055] The cover plate 201 and the bottom plate 203 are both 0.4 mm thick.

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

[0057] The manufacturing method of the loop-type heat spreader includes the following steps:

[0058] a) Machining cover plate 201, base plate 203, and heat dissipation fins;

[0059] b) The spiral braided mesh is annealed and cooled to room temperature;

[0060] c) Place the support column inside the graphite mold, and place the spiral woven mesh as shown in the image. Figure 10 In the graphite mold groove shown, the first planar wire mesh 101 is fixed on the base plate 203, and the base plate 203 is fastened to the graphite mold.

[0061] d) The base plate 203, the first planar wire mesh 101, the spiral woven mesh 106, the graphite mold, and the support column 102 are placed together in a multi-functional sintering furnace and sintered under a pressure of 20 MPa; the cover plate 201 is sintered directly with the second planar wire mesh 202.

[0062] e) The sintered base plate 203, first planar wire mesh 101, spiral woven mesh 106 and support column 102 are placed in an annealing furnace for annealing, and the saturated water absorption is measured after cooling to room temperature.

[0063] f) The bottom plate 203, the first flat wire mesh 101, the spiral woven mesh 106 and the support column 102, after being sintered, are riveted together with the cover plate 201 under the riveting fixture and then placed on the diffusion welding furnace to be welded together.

[0064] g) After the heat spreader is annealed, a first vacuum process is performed to make the vacuum degree inside the heat spreader reach 30Pa~40Pa.

[0065] h) The second degassing process involves heating the heat spreader plate at 120°C using a baking pan, causing non-condensable gases inside the heat spreader plate to accumulate in the injection pipe. By precisely cutting the injection pipe, the amount of non-condensable gases inside the heat spreader plate is further reduced, allowing the vacuum degree inside the heat spreader plate to reach 0.01Pa~0.001Pa.

[0066] i) Seal and weld the cut-off position of the injection pipe connected to the heat spreader.

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

[0068] The present invention provides a loop-type heat sink that can be used for heat dissipation of high-power electronic chips. The heat is transferred to the evaporation end of the loop-type heat sink through heat conduction. The heated liquid in the evaporation end 302 absorbs heat by vaporization, and the gas flows to the condensation end 301 through the steam discharge channel 108. The gas in the condensation end 301 releases heat and liquefies into liquid. The liquid flows into the high capillary force spiral woven mesh 106 and flows into the evaporation end 302 under the action of capillary force. The heat released by the liquefaction of gas in the condensation end 301 is transferred to the heat dissipation fins 204. The heat dissipation fins 204 undergo forced convection heat exchange with the air under the action of the centrifugal fan 205, and carry the heat to the outside atmosphere through the air.

[0069] The high-performance loop-type heat sink provided by this invention is applied to laptops. Traditional laptops and other communication devices mostly use a structure where multiple flattened heat pipes are welded together. Due to the multiple heat pipe walls, gas-liquid exchange between the heat pipes is impossible, thus limiting their maximum power and resulting in relatively high thermal resistance. Furthermore, the traditional laptop cooling system involves: heat from the chip being transferred to a copper heat sink via heat conduction, where the heat sink acts as a heat spreader, transferring heat to the heat pipes. Heat dissipation fins are welded to the heat pipes, and forced convection heat exchange with the air carries the heat into the external environment. Because the chip's heat needs to be transferred layer by layer to reach the heat dissipation fins, the thermal resistance is high. The high-performance loop-type heat sink and heat dissipation system of this invention address the issue of heat generated by high-power chips in laptops. Heat is transferred to the high-performance loop-type heat sink via heat conduction, and then to the heat dissipation fins. Under the action of a fan, the heat dissipation fins undergo forced convection heat exchange with the air, transferring the heat to the outside environment. This heat sink and heat dissipation system replaces multiple flattened heat pipes and copper heat sinks with a high-performance loop-type heat sink. Heat generated by high-power chips is directly transferred to the high-performance loop-type heat sink, solving the problem of heat transfer through multiple layers, reducing thermal resistance. Furthermore, the high-performance loop-type heat sink has a higher thermal conductivity than traditional multiple flattened heat pipes and also increases the maximum power output.

[0070] The above embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A loop-type heat spreader, characterized in that, The shell consists of a cover plate (201) and a base plate (203). The two ends are symmetrically connected as condensing ends (301) and the middle connecting part is the evaporating end (302). The condensing end (301) includes an annular channel, which includes a steam exhaust channel (108), a steam heat dissipation channel (103), and a liquid return channel (105) in sequence. The annular channel is connected to the evaporating end (302), and the part enclosed by the annular channel is a hollow part (104). The heat dissipation fins (204) are provided on the outside of the heat spreader condensing end (301), and a centrifugal fan (205) is provided in the hollow part (104) to provide airflow. The housing contains a liquid-absorbing core structure; The liquid-absorbing core structure inside the evaporation end (302) includes a first planar wire mesh (101); the liquid-absorbing core structure also includes a spiral braided mesh (106), the spiral braided mesh (106) penetrates the vapor heat dissipation channel (103) and the liquid return channel (105) of the condensation end (301), the spiral braided mesh (106) inside the evaporation end (302) surrounds the first planar wire mesh (101) and is sintered with the first planar wire mesh (101), in addition, there is a second planar wire mesh (202) welded to the cover plate (201). It also includes a support column (102), which is located at the steam heat dissipation channel (103) of the evaporation end (302) and the condensation end (301) to support the spiral woven mesh (106) and the first planar wire mesh (101). The three-dimensional phase change structure of the heat exchanger adopts the overall symmetrical evaporation structure. The heat exchanger contains deionized water as a working fluid. When the evaporation end (302) is heated, the working fluid absorbs heat and vaporizes from liquid to gas. Under pressure, the gas flows into the annular channel and first enters the steam heat dissipation channel (103) through the steam discharge channel (108). At the hollow part (104), the heat dissipation fins (204) undergo forced air-cooled convection heat exchange with the air under the action of the centrifugal fan (205), which reduces the temperature of the heat exchanger. At this time, the gas releases heat and liquefies into liquid. The liquid flows to the spiral braided mesh (106) through the liquid return channel (105). Under the action of the capillary force of the spiral braided mesh (106), it flows back to the spiral braided mesh (106) in the evaporation end (302). Then, under the action of the permeation force, the liquid permeates from the spiral braided mesh (106) towards the first planar wire mesh (101), thus forming a gas-liquid circulation.

2. The loop-type heat spreader 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; the height ratio of the gas channel to the liquid channel in the condensation end (301) is 1:

2.

3. The loop-type heat spreader according to claim 1, characterized in that, The first planar wire mesh (101) adopts a two-layer wire mesh structure of 200 mesh + 100 mesh.

4. The loop-type heat spreader according to claim 1, characterized in that, The spacing between the support columns (102) at the evaporator end (302) and the heat source relative position (401) is 7 mm, and the spacing between the support columns (102) at the position without heat source relative position (107) is 10 mm; the spacing between the support columns (102) at the condenser end (301) is 10 mm.

5. A loop-type heat spreader 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) of the steam heat dissipation channel (103) and the liquid return channel (105).

6. The loop-type heat spreader according to claim 1, characterized in that, The cover plate (201) and the bottom plate (203) are both 0.4 mm thick.

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

8. A method for manufacturing a loop-type heat spreader, used to manufacture a loop-type heat spreader as described in any one of claims 1 to 7, characterized in that, The steps are as follows: a) Machining cover plate (201), base plate (203), and heat dissipation fins; b) The spiral braided mesh (106) is annealed and cooled to room temperature; c) Place the support column inside the graphite mold, place the spiral woven mesh inside the graphite mold groove, fix the first planar wire mesh (101) on the base plate (203), and fasten the base plate (203) onto the graphite mold; d) The base plate (203), the first planar wire mesh (101), the spiral woven mesh (106), the graphite mold and the support column (102) are placed in a multi-functional sintering furnace and sintered under a pressure of 20MPa; the cover plate (201) is sintered directly with the second planar wire mesh (202); e) The base plate (203), the first planar wire mesh (101), the spiral woven mesh (106) and the support column (102) after sintering are placed in an annealing furnace for annealing, and the saturated water absorption is measured 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) after sintering are riveted together with the cover plate (201) under the riveting fixture and placed on the diffusion welding furnace to be welded together. g) After the heat spreader is annealed, a vacuum process is performed for the first time to make the vacuum degree inside the heat spreader reach 30Pa~40Pa. h) The second degassing process involves heating the heat spreader plate at 120°C using a baking pan, causing non-condensable gases inside the heat spreader plate to accumulate in the injection pipe. By precisely cutting the injection pipe, the amount of non-condensable gases inside the heat spreader plate is further reduced, allowing the vacuum degree inside the heat spreader plate to reach 0.01Pa~0.001Pa. i) Seal and weld the cut-off position of the injection pipe connected to the heat spreader. j) The heat spreader plate and the heat dissipation fins (204) are welded together, and the centrifugal fan (205) is installed in the hollow part (104).

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