Cold plate heat sink

Abstract

According to an embodiment of the present disclosure, there is provided a cold plate heat spreader including an outer frame including aluminum and provided with an inner space for accommodating a cooling liquid, a first outer surface of the outer frame for contacting an electronic device to be cooled, a heat exchange fin including aluminum and provided in the inner space, a sacrificial anode material layer in contact with at least one outer surface of the outer frame different from the first outer surface, the sacrificial anode material layer including a metal material having a higher metal activity than aluminum, and an oxide restricting portion surrounding the sacrificial anode material layer to prevent an oxide formed from the metal material from detaching from the cold plate heat spreader.

Description

Technical Field

[0001] The embodiments of this disclosure generally relate to the field of electronic device cooling technology, and more specifically, to a cold plate heat sink. Background Technology

[0002] Data center energy consumption is increasing daily. Traditional air-cooling solutions are inefficient and consume large amounts of energy, making them increasingly unable to meet the cooling capacity and economic feasibility requirements of data centers. Liquid cooling solutions, due to their high heat dissipation efficiency, have become an important technological direction for data center construction.

[0003] A relatively mature liquid cooling solution is cold plate liquid cooling. Currently, copper is widely used in the field of cold plate liquid cooling to manufacture cold plates. Copper has good thermal conductivity and is relatively easy to form. Furthermore, passivated copper has good corrosion resistance, erosion resistance, and high reliability. The most mature materials for cold plates are currently copper C1100 or C1020.

[0004] However, copper cold plates are expensive. With the widespread deployment of liquid-cooled servers, the cost of the cold plates is a crucial factor to consider, making cost optimization a key objective. Therefore, there is a need for improved liquid-cooled cold plate solutions. Summary of the Invention

[0005] The purpose of this disclosure is to provide a cold plate heat sink that at least partially solves the above-mentioned problems and other potential problems.

[0006] In one aspect of this disclosure, a cold plate heat sink is provided, comprising: an outer frame comprising aluminum and having an internal space for containing coolant, the first outer surface of the outer frame being for contacting an electronic device to be cooled; heat exchange fins comprising aluminum and disposed in the internal space; a sacrificial anode material layer in contact with at least one outer surface of the outer frame different from the first outer surface, the sacrificial anode material layer comprising a metallic material having a higher metallic activity than aluminum; and an oxide limiting portion surrounding the sacrificial anode material layer to prevent oxides formed by the metallic material from detaching from the cold plate heat sink.

[0007] In some embodiments, the oxide limiting portion includes a breathable covering layer that covers the sacrificial anode material layer, the breathable covering layer allowing air to pass through and preventing oxides formed from the metal material from detaching from the breathable covering layer.

[0008] In some embodiments, the breathable coating layer is formed on the sacrificial anode material layer by a spraying process.

[0009] In some embodiments, the sacrificial anode material layer comprises a magnesium alloy.

[0010] In some embodiments, the oxide confinement portion includes a cavity surrounding the sacrificial anode material layer.

[0011] In some embodiments, the cavity is closed.

[0012] In some embodiments, the sacrificial anode material layer comprises magnesium or a magnesium alloy.

[0013] In some embodiments, at least one vent is formed on the wall of the cavity, the at least one vent allowing air to pass through and preventing oxides formed from the metallic material from detaching from the cavity.

[0014] In some embodiments, the sacrificial anode material layer comprises a magnesium alloy.

[0015] In embodiments according to this disclosure, the cost of the cold plate server can be significantly reduced by using an aluminum-containing material to manufacture the outer frame and heat exchange fins. When using an aluminum outer frame and heat exchange fins, brush corrosion can be reduced by adding a sacrificial anode material layer to protect the outer frame and heat exchange fins. Furthermore, the oxide limiting portion prevents oxide powder formed by the sacrificial anode material layer from falling onto the electronic device, thereby avoiding contamination and preventing short circuits.

[0016] It should be understood that the content described in this section is not intended to limit the key or essential features of the embodiments of this disclosure, nor is it intended to restrict the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0017] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. In the drawings, the same or similar reference numerals denote the same or similar elements, wherein:

[0018] Figure 1 A schematic diagram of a cold plate heat sink according to an embodiment of the present disclosure is shown; and

[0019] Figure 2 A schematic diagram of a cold plate heat sink according to another embodiment of the present disclosure is shown. Detailed Implementation

[0020] Preferred embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0021] The term "comprising" and its variations as used herein signify open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "at least partially based on". The terms "one example embodiment" and "one embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first", "second", etc., may refer to different or the same objects.

[0022] As mentioned above, copper cold plates are expensive. With the widespread deployment of liquid-cooled servers, the cost of the cold plates is a crucial factor to consider, making cost optimization a key objective. Lower-cost aluminum is a viable option for cold plate materials. However, aluminum cold plates also have significant disadvantages, including the following three points.

[0023] First, aluminum has lower thermal conductivity than copper. However, through optimized design, the impact of this difference is acceptable for data centers.

[0024] Furthermore, aluminum exhibits dual reactivity, reacting with both acids and alkalis. Therefore, when using aluminum to manufacture cold-rolled steel plates, the quality requirements for the coolant in the radiator are much stricter. For example, the pH range of the coolant must be very narrow, and during chemical cleaning processes, acid pickling or any chemical cleaning agents must be strictly controlled, necessitating the use of aluminum alloy-specific cleaning agents. However, with rigorous and professional water quality control of the coolant and strict control over the materials used throughout the liquid cooling loop, the impact of this risk can be mitigated.

[0025] Furthermore, aluminum, due to its relatively soft material, is susceptible to erosion corrosion in cold-plate liquid cooling systems. Erosion corrosion, also known as wear corrosion, is a metal damage phenomenon caused by high-speed relative motion between the metal surface and the fluid. It is the result of the interaction between erosion and corrosion in pipelines and is a highly damaging form of localized corrosion. After passivation, aluminum forms a dense alumina coating on its surface. When it reaches a thickness of micrometers, this dense oxide layer will prevent further corrosion and oxidation of the aluminum. However, because aluminum is relatively soft, this dense layer is easily washed away when subjected to water erosion in a water system. Due to aluminum's high chemical reactivity, it readily reforms a dense oxide layer. This dense oxide layer is then easily washed away again during water erosion, creating a vicious cycle. Over long-term use, the aluminum material is easily eroded and consumed, leading to deformation at weak points and even leaks. Therefore, after long-term operation, risks such as damaged aluminum fins and leaks at welded locations may occur, posing a reliability hazard.

[0026] One possible approach to mitigating the risks posed by erosion corrosion is to consider the thickness and type of aluminum fins, making the internal structure of the aluminum cold plate as thick as possible to avoid damage from erosion corrosion. This design carries lower risk at lower heat flux densities, but as chip heat flux densities increase, the internal structure and fins of the cold plate become increasingly thinner. This makes it difficult to simply rely on the thickness of the aluminum material to resist erosion corrosion. Therefore, solutions to resist erosion corrosion become an important consideration in the design of aluminum cold plates.

[0027] To mitigate the impact of erosion corrosion on aluminum cold plates, embodiments of this disclosure provide a cold plate heat sink in which a sacrificial anode material layer is used to protect the aluminum cold plate. The following will be combined with... Figure 1 and Figure 2 The principles of embodiments according to this disclosure will be described.

[0028] Figure 1 A schematic diagram of a cold plate heat sink 10 according to an embodiment of the present disclosure is shown. Figure 1 As shown, the cold plate heat sink 10 described herein generally includes an outer frame 11, heat exchange fins 12, a sacrificial anode material layer 13, and an oxide confinement section 14.

[0029] The outer frame 11 comprises aluminum and has an internal space 110 for containing coolant. The coolant may be, for example, deionized water, an alcohol-based coolant, or other types, and the embodiments disclosed herein are not limited thereto. Heat exchange fins 12 comprise aluminum and are disposed within the internal space 110. The heat exchange fins 12 may be spaced apart within the internal space 110 to transfer heat between the coolant and the outer frame 11. The outer frame 11 and the heat exchange fins 12 may be made of, for example, aluminum alloy or other aluminum-containing materials. A first outer surface 111 of the outer frame 11 is used to contact the electronic device 20 to be cooled.

[0030] In one embodiment, such as Figure 1 As shown, the electronic device 20 includes a motherboard 21 and a central processing unit (CPU) 22 disposed on the motherboard 21. The first outer surface 111 of the outer frame 11 contacts the CPU 22. When the electronic device 20 is running, the heat generated by the CPU 22 can be carried away by coolant in the internal space 110. In other embodiments, the electronic device 20 may be of other types, and the embodiments disclosed herein are not limited thereto.

[0031] like Figure 1 As shown, the sacrificial anode material layer 13 contacts at least one outer surface of the outer frame 11 that is different from the first outer surface 111. The sacrificial anode material layer 13 comprises a metallic material with higher metallic activity than aluminum. In one embodiment, such as Figure 1As shown, a sacrificial anode material layer 13 is provided on the second outer surface 112 opposite to the first outer surface 111 and the side surface 113 located between the first outer surface 111 and the second outer surface 112 of the outer frame 11.

[0032] When two metals with different reactivity come into contact, electrons flow from the negatively charged metal (anode) to the positively charged metal (cathode). When these two metals are in contact, the rate of ion release to the outside is much faster than with a single metal, and the corrosion is limited to the anode material (the more reactive metal), while the cathode material (the less reactive metal) is protected. Therefore, by providing a sacrificial anode material layer 13 on the outer surface of the outer frame 11, the sacrificial anode material layer 13 can be used to protect the aluminum-containing outer frame 11 and heat exchange fins 12, mitigating the erosive corrosion of the inner surface of the outer frame 11 and the heat exchange fins 12 by the coolant.

[0033] In one embodiment, the sacrificial anode material layer 13 comprises a magnesium alloy, wherein magnesium has higher metallic activity than aluminum. Due to the potential difference between magnesium and aluminum, when aluminum is subjected to erosion corrosion, aluminum acts as the cathode material, effectively slowing down the rate of electrochemical corrosion. Meanwhile, during the long-term use of the aluminum cold plate, magnesium, acting as the sacrificial anode, is replaced and oxidized by oxygen in the air to form magnesium oxide. In this way, magnesium, as the sacrificial anode material, can be used to protect the outer frame 11 and the heat exchange fins 12 while maintaining a relatively thin thickness within the cold plate radiator 10.

[0034] Metals with higher reactivity than aluminum will form oxide powder during the oxidation process. If this oxide powder falls onto the motherboard 21, it can contaminate the electronic device 20 and potentially cause a short circuit. Therefore, such as Figure 1 As shown, the oxide limiting part 14 is provided to surround the sacrificial anode material layer 13 to prevent the oxide formed by the metal material from detaching from the cold plate heat sink 10, thereby preventing oxide powder from contaminating the electronic device 20 and preventing short circuits.

[0035] In some embodiments, such as Figure 1 As shown, the oxide limiting section 14 includes a breathable coating layer 141 that covers the sacrificial anode material layer 13. The breathable coating layer 141 allows air to pass through while preventing oxides formed from the metallic material from detaching from the breathable coating layer 141. With this arrangement, oxygen passing through the breathable coating layer 141 can perform alternative oxidation on the sacrificial anode material layer 13, thereby protecting the aluminum-containing outer frame 11 and heat exchange fins 12. Furthermore, since the breathable coating layer 141 can prevent oxides formed from the metallic material from detaching from the breathable coating layer 141, it is possible to prevent oxide powder from contaminating the electronic device 20 and to prevent short circuits.

[0036] like Figure 1 As shown, when the sacrificial anode material layer 13 covers the second outer surface 112 and side surface 113 of the outer frame 11, the breathable covering layer 141 also covers the sacrificial anode material layer 13 at the second outer surface 112 and side surface 113 of the outer frame 11, thereby preventing oxide powder from falling off.

[0037] In some embodiments, the sacrificial anode material layer 13 may be provided only on a single outer surface or a portion of a single outer surface of the outer frame 11. For example, the sacrificial anode material layer 13 may be provided only on the second outer surface 112 or a portion thereof of the outer frame 11, or only on the side surface 113 or a portion thereof of the outer frame. Accordingly, the breathable covering layer 141 may cover the sacrificial anode material layer 13 on the respective outer surface.

[0038] In some embodiments, the breathable coating layer 141 can be formed on the sacrificial anode material layer 13 by a spraying process. In other embodiments, the breathable coating layer 141 can be formed on the sacrificial anode material layer 13 by an adhesive bonding method. In other embodiments, the breathable coating layer 141 can be formed on the sacrificial anode material layer 13 by other methods, and the embodiments of this disclosure are not limited thereto.

[0039] Figure 2 A schematic diagram of the structure of a cold plate heat sink 10 according to another embodiment of the present disclosure is shown. Figure 2 The structure of the cold plate heat sink 10 shown is similar to Figure 1 The heatsink 10 shown has a similar structure, the main difference being the use of a different structure for the oxide limiting part 14 to prevent oxide powder from falling off. The differences between the two will be described in detail below, while the similarities will not be repeated.

[0040] like Figure 2 As shown, the sacrificial anode material layer 13 is disposed on the second outer surface 112 of the outer frame 11. To prevent oxide powder formed from the metal material in the sacrificial anode material layer 13 from falling off, the oxide confinement portion 14 includes a cavity 142 formed on the top of the outer frame 11, the cavity 142 surrounding the sacrificial anode material layer 13. The cavity 142 is closed and reserved with air to provide the oxygen required for the sacrificial anode material layer 13 to undergo substitution oxidation. At the same time, the cavity 142 provides space for the sacrificial anode material layer 13 to expand and contain oxide powder during substitution oxidation.

[0041] In one embodiment, the sacrificial anode material layer 13 comprises magnesium or a magnesium alloy. Due to the potential difference between magnesium and aluminum, when aluminum is subjected to erosion corrosion, aluminum acts as the cathode material, effectively slowing down the rate of electrochemical corrosion. Meanwhile, during the long-term use of the aluminum cold plate, magnesium, acting as the sacrificial anode, is oxidized by oxygen in the cavity 142 to form magnesium oxide. In this way, magnesium, as the sacrificial anode material, can be used to protect the outer frame 11 and the heat exchange fins 12 while maintaining a relatively thin thickness within the cold plate radiator 10.

[0042] In one embodiment, at least one vent (not shown) may be formed on the wall of the cavity 142. The vent allows air to pass through and prevents oxides formed of metallic material from detaching from the cavity 142. This arrangement also enables the sacrificial anode material layer 13 to protect the outer frame 11 and the heat exchange fins 12, and prevents oxide powder from falling off. In such an embodiment, the sacrificial anode material layer 13 may comprise a magnesium alloy.

[0043] It should be understood that, in the above text, in conjunction with Figure 1 and Figure 2 An exemplary structure of the oxide limiting portion 14 has been described. In other embodiments, the oxide limiting portion 14 may have other structures.

[0044] Although magnesium and magnesium alloys have been used above as examples of metallic materials with higher metal activity than aluminum in the sacrificial anode material layer 13 to describe the principles of this disclosure, it should be understood that the sacrificial anode material layer 13 may contain other metallic materials with higher metal activity than aluminum, which can also achieve protection of the outer frame 11 and the heat exchange fins 12.

[0045] The embodiments of this disclosure utilize the sacrificial anode protection effect to provide corrosion protection for the internal structure of the aluminum cold plate heat sink, thereby improving the overall reliability of the aluminum cold plate without sacrificing its heat dissipation performance, solely through changes in its physical structure. Furthermore, the cold plate heat sink according to the embodiments of this disclosure offers a significant cost advantage, reducing the cost of the cold plate by approximately 30%.

[0046] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, and are not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A cold plate heat sink (10), comprising: An outer frame (11) comprising aluminum and having an internal space (110) for containing coolant, the first outer surface (111) of the outer frame (11) being for contacting an electronic device (20) to be cooled; Heat exchange fins (12), comprising aluminum and disposed in the internal space (110); The sacrificial anode material layer (13) is in contact with at least one outer surface of the outer frame (11) that is different from the first outer surface (111), and the sacrificial anode material layer (13) contains a metallic material with higher metallic activity than aluminum; as well as An oxide limiting section (14) surrounds the sacrificial anode material layer (13) to prevent the oxide formed by the metal material from detaching from the cold plate heat sink (10).

2. The cold plate heat sink (10) according to claim 1, wherein the oxide limiting part (14) includes a breathable covering layer (141) covering the sacrificial anode material layer (13), the breathable covering layer (141) allowing air to pass through and preventing oxides formed of the metal material from detaching from the breathable covering layer (141).

3. The cold plate heat sink (10) according to claim 2, wherein the breathable covering layer (141) is formed on the sacrificial anode material layer (13) by a spraying process.

4. The cold plate heat sink (10) according to claim 2, wherein the sacrificial anode material layer (13) comprises a magnesium alloy.

5. The cold plate heat sink (10) according to claim 1, wherein the oxide limiting portion (14) includes a cavity (142) surrounding the sacrificial anode material layer (13).

6. The cold plate heat sink (10) according to claim 5, wherein the cavity (142) is closed.

7. The cold plate heat sink (10) according to claim 6, wherein the sacrificial anode material layer (13) comprises magnesium or a magnesium alloy.

8. The cold plate heat sink (10) according to claim 5, wherein at least one vent is formed on the wall of the cavity (142), the at least one vent allowing air to pass through and preventing oxides formed of the metal material from detaching from the cavity (142).

9. The cold plate heat sink (10) according to claim 8, wherein the sacrificial anode material layer (13) comprises a magnesium alloy.

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