Micro-channel capillary structure and pump-driven micro-channel phase change liquid cooling cold plate

Abstract

The invention relates to the technical field of liquid cooling heat dissipation, in particular to a micro-channel capillary structure and a pump-driven micro-channel phase change liquid cooling plate comprising the micro-channel capillary structure. The micro-channel capillary structure comprises a plurality of porous structure layers which are sequentially stacked from bottom to top, each porous structure layer is layered micro-nano through hole copper, in every two adjacent porous structure layers, the porosity of the upper porous structure layer is larger than that of the lower porous structure layer, and the porosity of the lower porous structure layer is larger than that of the upper porous structure layer. The aperture of the upper porous structure layer is larger than that of the lower porous structure layer. The preparation method is simple, the preparation is easy, the preparation efficiency is high, the consistency is good, and the preparation of the micro-nano through hole copper can realize a micron-sized capillary structure, so that the micro-nano through hole copper has very good capillary characteristics and is beneficial to rapid phase change of a refrigerant medium from a liquid state to a gas state.

Description

Technical Field

[0001] This invention relates to the field of liquid cooling technology, and more particularly to a microchannel capillary structure and a pump-driven microchannel phase change liquid cooling plate including the microchannel capillary structure. Background Technology

[0002] With the increasing power of AI chips and data center servers, liquid cooling technology has become a cost-effective and efficient temperature control method due to its advantages of low energy consumption, high heat dissipation, and low noise. Cold plate liquid cooling technology is one type of liquid cooling technology, and its combination with microchannel heat exchange technology further improves heat dissipation performance. Pump-driven microchannel phase change liquid cooling plates utilize the evaporation and heat absorption of liquid working fluid within the microchannel capillary structure to cool the heat source, resulting in more efficient heat exchange and greater application potential in the field of high-efficiency, compact heat exchange.

[0003] Currently, the microchannel capillary structure of pump-driven microchannel phase change liquid cooling plates is usually fabricated using mechanical machining to create microchannel structures. This mainly includes two types: 1) Machining into a spiral microchannel, characterized by a curved flow channel that extends the working fluid's residence time and enhances turbulent mixing; this structure is still equivalent to a single-phase liquid cooling plate; 2) Machining into a manifold-type microchannel, characterized by a branched flow channel design, with multi-stage manifolds integrated within the cold head, and a capillary core to enhance the uniformity of working fluid distribution. Patent document CN222382013U discloses a microchannel cooling plate that uses a microchannel formed by precision machining into a fine channel fin structure. However, conventional machining is difficult to use to fabricate micron-level capillary structures, resulting in very limited capillary effects in stimulating phase change in machined microchannel structures, which is not conducive to the rapid phase change of liquid working fluid to gas, and the machining efficiency is quite low.

[0004] Existing research attempts to use 3D printing technology to construct microchannels with 3D structures. Common structural features include a combination of circular (0.8mm–1.2mm diameter) and rectangular (0.2mm width, 0.5mm–2mm height) cross-sections, a slot spacing of 1.6mm, and the ability to combine capillary force with low flow resistance. While 3D-printed microchannel structures can be designed according to requirements, achieving good printing results for micron-sized (several micrometers to tens of micrometers) pore structures is generally difficult, and the cost of 3D printing is relatively high. Summary of the Invention

[0005] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a microchannel capillary structure with good capillary characteristics, high preparation efficiency and good consistency.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] This invention provides a microchannel capillary structure comprising multiple porous structure layers stacked sequentially from bottom to top. Each porous structure layer is a layered micro-nano via copper, and in two adjacent porous structure layers, the porosity of the upper porous structure layer is greater than that of the lower porous structure layer, and the pore diameter of the upper porous structure layer is greater than that of the lower porous structure layer.

[0008] Preferably, the porosity of each porous structure layer gradually increases from bottom to top and / or the pore size of each porous structure layer gradually increases from bottom to top.

[0009] Preferably, the thickness of each porous structure layer is equal or unequal.

[0010] Preferably, adjacent porous structural layers are interconnected.

[0011] Preferably, the porous structure layer consists of two layers, which are a lower layer and an upper layer stacked sequentially from bottom to top. The thickness of the lower layer and the upper layer are equal, or the thickness ratio of the lower layer to the upper layer is 1:2 to 4.

[0012] Preferably, the porosity of the lower layer is 65% to 80%, and the pore size of the lower layer is 30µm to 100µm; the porosity of the upper layer is above 80%, and the pore size of the upper layer is 200µm to 500µm.

[0013] Preferably, the porous structure layer has three layers, which are a lower layer, a middle layer and an upper layer stacked sequentially from bottom to top. The thickness of the lower layer, the middle layer and the upper layer are equal, or the thickness ratio of the lower layer, the middle layer and the upper layer is 1:2 to 4:4 to 6.

[0014] Preferably, the porosity of the lower layer is 60% to 65%, and the pore size of the lower layer is 30µm to 100µm; the porosity of the middle layer is 75% to 80%, and the pore size of the middle layer is 100µm to 300µm; the porosity of the upper layer is above 90%, and the pore size of the upper layer is 300µm to 500µm.

[0015] The present invention also provides a pump-driven microchannel phase change liquid cooling plate, comprising the microchannel capillary structure as described above.

[0016] Preferably, it also includes a shell, the interior of which is hollow to form a sealed inner cavity, and fluid inlet and fluid outlet connected to the inner cavity are respectively provided on opposite sides of the shell, and microchannel capillary structure is provided in the inner cavity and located between the fluid inlet and fluid outlet.

[0017] Compared with the prior art, the present invention has significant progress:

[0018] The microchannel capillary structure of this invention is composed of micro / nano-porous copper with a layered gradient of porosity and pore size. It is easy to prepare, has high preparation efficiency and good consistency. At the same time, the preparation of micro / nano-porous copper can realize micron-scale capillary structures, thus having very good capillary characteristics, which is conducive to the rapid liquid-to-gas phase transition of the cold medium. Furthermore, the layered gradient of porosity and pore size allows the porous structure layer closer to the heat source to have smaller porosity and pore size, thus having a larger specific surface area and high thermal conductivity. This can stimulate the liquid working medium to quickly absorb heat from the heat source and generate a phase transition, making the phase transition start-up fast and facilitating the rapid nucleation and growth of gas. The porous structure layer farther from the heat source has larger porosity and pore size, thus facilitating the growth of the gas after the phase transition to form bubbles and rapidly rise and be discharged, reducing the resistance to the upward flow of gas during formation. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the first embodiment of the pump-driven microchannel phase change liquid cooling plate of the present invention.

[0020] Figure 2 yes Figure 1 A cross-sectional view along the AA direction.

[0021] Figure 3 This is a schematic diagram of the second embodiment of the pump-driven microchannel phase change liquid cooling plate of the present invention.

[0022] Figure 4 This is a schematic diagram of the third embodiment of the pump-driven microchannel phase change liquid cooling plate of the present invention.

[0023] Figure 5 This is a schematic diagram of the fourth embodiment of the pump-driven microchannel phase change liquid cooling plate of the present invention.

[0024] The reference numerals in the attached figures are explained as follows:

[0025] 100. Microchannel capillary structure; 1. Porous structure layer; 11. Lower layer; 12. Middle layer; 13. Upper layer; 200. Shell; 201. Inner cavity; 202. Fluid inlet; 203. Fluid outlet; 300. Heat source. Detailed Implementation

[0026] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0027] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a metallurgical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0029] Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0030] Figures 1 to 5 An embodiment of the microchannel capillary structure provided by the present invention is shown.

[0031] like Figure 1 , Figure 3 , Figure 4 and Figure 5 As shown, the microchannel capillary structure 100 of this embodiment includes multiple porous structure layers 1 stacked sequentially from bottom to top. Each porous structure layer 1 is a layered micro / nano-perforated copper structure. In adjacent porous structure layers 1, the porosity of the upper porous structure layer 1 is greater than that of the lower porous structure layer 1, and the pore size of the upper porous structure layer 1 is greater than that of the lower porous structure layer 1, thereby forming a microchannel capillary structure 100 with a layered gradient in porosity and pore size. This microchannel capillary structure 100 is used as the capillary structure of a pump-driven microchannel phase change liquid cooling plate. The bottommost porous structure layer 1 with the smallest porosity and pore size is closest to the side of the pump-driven microchannel phase change liquid cooling plate that is in contact with the heat source 300 (such as a chip).

[0032] The microchannel capillary structure 100 of this embodiment is composed of micro-nano porous copper with a layered gradient of porosity and pore size. It is easy to prepare, has high preparation efficiency and good consistency. At the same time, the preparation of micro-nano porous copper can realize micron-scale capillary structure, thus having very good capillary characteristics, which is conducive to the rapid liquid-to-gas phase transition of the cold medium. Furthermore, the layered gradient of porosity and pore size allows the porous structure layer 1 closer to the heat source 300 to have a smaller porosity and pore size, thus having a larger specific surface area and high thermal conductivity. This can stimulate the liquid working medium to quickly absorb heat from the heat source 300 to generate a phase transition, making the phase transition start fast and facilitating the rapid nucleation and growth of gas. The porous structure layer 1 farther from the heat source 300 has a larger porosity and pore size, which facilitates the growth of gas after the phase transition to form bubbles and their rapid rise and discharge, reducing the resistance to the upward flow of gas during formation.

[0033] In this embodiment, preferably, the porosity of each porous structure layer 1 can be set to gradually increase from bottom to top, and the pore size of each porous structure layer 1 can also be set to gradually increase from bottom to top, thereby making the gradient changes of porosity and pore size of the microchannel capillary structure 100 smoother.

[0034] In this embodiment, as Figure 1 and Figure 4 As shown, the thickness of each porous structure layer 1 can be set to be equal, so that the microchannel capillary structure 100 is a multilayer structure of uniform thickness. Figure 3 and Figure 5 As shown, the thickness of each porous structure layer 1 can also be set to be unequal, so that the microchannel capillary structure 100 is a multilayer structure with non-uniform thickness.

[0035] In this embodiment, preferably, adjacent porous structure layers 1 are interconnected, so that the multiple porous structure layers 1 are composited into a whole, ensuring the integrity of the microchannel capillary structure 100. The method of interconnection between adjacent porous structure layers 1 is not limited, but metallurgical connection is preferred, such as rolling composite.

[0036] In this embodiment, the number of porous structure layers 1 of the microchannel capillary structure 100 is not limited, but two or three layers are preferred.

[0037] like Figure 1As shown, in the first embodiment, the porous structure layer 1 of the microchannel capillary structure 100 has three layers. The three porous structure layers 1 are a lower layer 11, an intermediate layer 12, and an upper layer 13 stacked sequentially from bottom to top. The thicknesses of the lower layer 11, the intermediate layer 12, and the upper layer 13 are equal, making the microchannel capillary structure 100 a uniformly thick three-layer structure. Preferably, the thickness of the microchannel capillary structure 100 is 4 mm, and the thicknesses of the lower layer 11, the intermediate layer 12, and the upper layer 13 are all 1.33 mm. Among them, the lower layer 11 is closest to the heat source 300. Preferably, the porosity of the lower layer 11 is 60% to 65%, and the pore size of the lower layer 11 is 30 µm to 100 µm, with 30 µm to 50 µm being more preferred. The lower layer 11 has a large specific surface area and high thermal conductivity to stimulate a rapid phase change of the liquid working fluid, making the phase change start-up fast and facilitating rapid nucleation and growth of the gas. The intermediate layer 12 has a porosity of 75%–80% and a pore size of 100µm–300µm. The intermediate layer 12 serves to balance flow resistance and heat transfer. The upper layer 13 has a porosity of over 90% and a pore size of 300µm–500µm. The upper layer 13 facilitates the growth of the gas after phase change into bubbles, allowing them to rise and dissipate rapidly, reducing resistance to upward flow during gas formation.

[0038] like Figure 3 As shown, in the second embodiment, the porous structure layer 1 of the microchannel capillary structure 100 has three layers. The three porous structure layers 1 are a lower layer 11, an intermediate layer 12, and an upper layer 13 stacked sequentially from bottom to top. The thicknesses of the lower layer 11, the intermediate layer 12, and the upper layer 13 are not equal, and the thickness ratio of the lower layer 11, the intermediate layer 12, and the upper layer 13 is 1:2 to 4:4 to 6, making the microchannel capillary structure 100 a non-uniform thickness three-layer structure. Preferably, the thickness of the microchannel capillary structure 100 is 4 mm, the thickness ratio of the lower layer 11, the intermediate layer 12, and the upper layer 13 is 1:3:5, and the thicknesses of the lower layer 11, the intermediate layer 12, and the upper layer 13 are 0.44 mm, 1.33 mm, and 2.22 mm, respectively. The lower layer 11 is closest to the heat source 300. Preferably, the lower layer 11 has a porosity of 60%–65% and a pore size of 30µm–100µm, with 30µm–50µm being more preferred. The lower layer 11 possesses a large specific surface area and high thermal conductivity to induce a rapid phase change in the liquid working fluid, enabling quick initiation of the phase change and facilitating rapid gas nucleation and growth. The middle layer 12 has a porosity of 75%–80% and a pore size of 100µm–300µm. The middle layer 12 serves to balance flow resistance and heat transfer. The upper layer 13 has a porosity of over 90% and a pore size of 300µm–500µm. The upper layer 13 facilitates the growth of the phase-change gas into bubbles, allowing for rapid ascent and expulsion, reducing resistance to upward flow during gas formation.

[0039] like Figure 4 As shown, in the third embodiment, the porous structure layer 1 of the microchannel capillary structure 100 has two layers. The two porous structure layers 1 are a lower layer 11 and an upper layer 13 stacked sequentially from bottom to top. The thickness of the lower layer 11 and the upper layer 13 is equal, making the microchannel capillary structure 100 a two-layer structure of uniform thickness. Preferably, the thickness of the microchannel capillary structure 100 is 4 mm, and the thickness of both the lower layer 11 and the upper layer 13 is 2 mm. Among them, the lower layer 11 is closest to the heat source 300. Preferably, the porosity of the lower layer 11 is 65% to 80%, more preferably 65% ​​to 70%, and the pore size of the lower layer 11 is 30 µm to 100 µm, more preferably 30 µm to 50 µm. The lower layer 11 has a large specific surface area and high thermal conductivity to stimulate a rapid phase change of the liquid working fluid, making the phase change start-up fast and facilitating the rapid nucleation and growth of the gas. The porosity of the upper layer 13 is above 80%, with 85% to 90% being more preferred. The pore size of the upper layer 13 is 200µm to 500µm, with 200µm to 300µm being more preferred. The upper layer 13 facilitates the growth of the gas after phase change to form bubbles and allows them to rise and be discharged quickly, reducing the resistance to the upward flow of the gas during formation.

[0040] like Figure 5 As shown, in the fourth embodiment, the porous structure layer 1 of the microchannel capillary structure 100 has two layers. The two porous structure layers 1 are a lower layer 11 and an upper layer 13 stacked sequentially from bottom to top. The thicknesses of the lower layer 11 and the upper layer 13 are not equal, and the thickness ratio of the lower layer 11 to the upper layer 13 is 1:2 to 4, making the microchannel capillary structure 100 a non-uniform thickness two-layer structure. Preferably, the thickness of the microchannel capillary structure 100 is 4 mm, the thickness ratio of the lower layer 11 to the upper layer 13 is 1:3, and the thicknesses of the lower layer 11 and the upper layer 13 are 1 mm and 3 mm, respectively. The lower layer 11 is closest to the heat source 300. Preferably, the porosity of the lower layer 11 is 65%–80%, more preferably 65%–70%, and the pore size of the lower layer 11 is 30µm–100µm, more preferably 30µm–50µm. The lower layer 11 has a large specific surface area and high thermal conductivity to induce a rapid phase change in the liquid working fluid, enabling the phase change to start quickly and facilitating rapid nucleation and growth of the gas. The porosity of the upper layer 13 is above 80%, more preferably 85%–90%, and the pore size of the upper layer 13 is 200µm–500µm, more preferably 200µm–300µm. The upper layer 13 facilitates the growth of the gas after the phase change into bubbles, which then rise and escape rapidly, reducing the resistance to upward flow during gas formation.

[0041] like Figures 1 to 5 As shown, based on the microchannel capillary structure of the present invention, this embodiment also provides a pump-driven microchannel phase change liquid cooling plate. The pump-driven microchannel phase change liquid cooling plate of this embodiment includes any of the microchannel capillary structures 100 described above.

[0042] The pump-driven microchannel phase change liquid cooling plate of this embodiment also includes a housing 200, which is preferably a copper housing. The housing 200 is hollow inside to form a sealed inner cavity 201. Fluid inlet 202 and fluid outlet 203 communicating with the inner cavity 201 are respectively provided on opposite sides of the housing 200. The microchannel capillary structure 100 is disposed in the inner cavity 201 and located between the fluid inlet 202 and the fluid outlet 203. The lower side of the housing 200 is used to attach to the heat source 300 (such as a chip). The microchannel capillary structure 100 is disposed at the bottom of the inner cavity 201 at a position corresponding to the heat source 300, and the lowest porous structure layer 1 (lower layer 11) of the microchannel capillary structure 100 with the smallest porosity and pore size is attached to the bottom wall of the inner cavity 201. The liquid working fluid enters the inner cavity 201 from the fluid inlet 202, wets the microchannel capillary structure 100, and absorbs the heat from the heat source 300, resulting in a phase change in the microchannel capillary structure 100. After the phase change, the working fluid is discharged from the fluid outlet 203, which plays a role in dissipating heat from the heat source 300.

[0043] like Figure 1 and Figure 2 As shown, this is a first embodiment of the pump-driven microchannel phase change liquid cooling plate of the present invention, which adopts the microchannel capillary structure 100 of the first embodiment described above.

[0044] like Figure 3 As shown, this is a second embodiment of the pump-driven microchannel phase change liquid cooling plate of the present invention, which adopts the microchannel capillary structure 100 of the second implementation method described above.

[0045] like Figure 4 As shown, this is the third embodiment of the pump-driven microchannel phase change liquid cooling plate of the present invention, which adopts the microchannel capillary structure 100 of the third implementation method described above.

[0046] like Figure 5 As shown, this is the fourth embodiment of the pump-driven microchannel phase change liquid cooling plate of the present invention, which adopts the microchannel capillary structure 100 of the fourth implementation method described above.

[0047] The pump-driven microchannel phase change liquid cooling plate of this embodiment uses micro-nano through-hole copper with layered gradient changes in porosity and pore size to form a microchannel capillary structure 100. This can effectively realize the fabrication of the pump-driven microchannel phase change liquid cooling plate, which can meet the heat dissipation requirements of units and integrated systems. In particular, it meets the development needs of current high-power AI chip integration and computing power, solves the thermal control required during the normal operation of chips and servers, and addresses the concerns and pain points of AI and high-power chips, servers and data centers being affected by high power consumption.

[0048] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A microchannel capillary structure, characterized in that, It includes multiple porous structure layers (1) stacked sequentially from bottom to top. Each porous structure layer (1) is a layered micro-nano through-hole copper. In two adjacent porous structure layers (1), the porosity of the upper porous structure layer (1) is greater than that of the lower porous structure layer (1), and the pore size of the upper porous structure layer (1) is greater than that of the lower porous structure layer (1).

2. The microchannel capillary structure according to claim 1, characterized in that, The porosity of each porous structure layer (1) gradually increases from bottom to top and / or the pore size of each porous structure layer (1) gradually increases from bottom to top.

3. The microchannel capillary structure according to claim 1, characterized in that, The thickness of each porous structure layer (1) may be equal or unequal.

4. The microchannel capillary structure according to claim 1, characterized in that, The two adjacent porous structure layers (1) are interconnected.

5. The microchannel capillary structure according to claim 1, characterized in that, The porous structure layer (1) has two layers, namely a lower layer (11) and an upper layer (13) stacked sequentially from bottom to top. The thickness of the lower layer (11) and the upper layer (13) are equal, or the thickness ratio of the lower layer (11) and the upper layer (13) is 1:2 to 4.

6. The microchannel capillary structure according to claim 5, characterized in that, The lower layer (11) has a porosity of 65% to 80% and a pore size of 30µm to 100µm; the upper layer (13) has a porosity of more than 80% and a pore size of 200µm to 500µm.

7. The microchannel capillary structure according to claim 1, characterized in that, The porous structure layer (1) has three layers, which are a lower layer (11), an intermediate layer (12) and an upper layer (13) stacked from bottom to top. The thicknesses of the lower layer (11), the intermediate layer (12) and the upper layer (13) are equal, or the thickness ratio of the lower layer (11), the intermediate layer (12) and the upper layer (13) is 1:2 to 4:4 to 6.

8. The microchannel capillary structure according to claim 7, characterized in that, The lower layer (11) has a porosity of 60% to 65% and a pore size of 30µm to 100µm; the middle layer (12) has a porosity of 75% to 80% and a pore size of 100µm to 300µm; the upper layer (13) has a porosity of more than 90% and a pore size of 300µm to 500µm.

9. A pump-driven microchannel phase change liquid cooling plate, characterized in that, Includes the microchannel capillary structure as described in any one of claims 1 to 8.

10. The pump-driven microchannel phase change liquid cooling plate according to claim 9, characterized in that, It also includes a housing (200), the interior of which is hollow to form a sealed inner cavity (201). On opposite sides of the housing (200) are respectively provided a fluid inlet (202) and a fluid outlet (203) communicating with the inner cavity (201). The microchannel capillary structure is disposed in the inner cavity (201) and located between the fluid inlet (202) and the fluid outlet (203).

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