Phase change cold plate for enhancing heat conduction

Abstract

A phase change cold plate for enhancing heat conduction comprises a shell, a cover plate and a phase change material, the shell and the cover plate form a closed cavity, and the closed cavity is filled with the phase change material; a clamping groove, a concave pit or a boss is arranged on the outer surface of the phase change cold plate, the clamping groove, the concave pit or the boss is used for being matched with a heating electronic component, and the heating electronic component is in close contact with the phase change cold plate. The overall heat conduction capacity and heat storage capacity of the phase change cold plate are considered, the problems of internal air heat resistance and local hot spots are solved, the overall performance of the phase change cold plate is improved, and it is ensured that the phase change cold plate meets the device temperature control requirement.

Description

Technical Field

[0001] The utility model belongs to the field of phase change cold plates, in particular to a phase change cold plate with enhanced heat conduction. Background Art

[0002] The traditional cooling method of electronic devices first considers air cooling and liquid cooling, but due to the large size of the cooling system, it cannot meet the trend of miniaturization of missile-borne weapons, and is not suitable for use in a near-insulated, weightless working environment, resulting in the traditional cooling method being rarely used in missile-borne weapons. The cooling system of existing missile-borne electronic devices mainly uses metal heat sinks, such as high thermal conductivity, high density aluminum alloy, copper and other materials, and uses the metal sensible heat to absorb heat to dissipate heat from electronic devices. Sensible heat absorption heat = metal mass * metal specific heat capacity * temperature difference, aluminum alloy specific heat capacity is about 0.88×10^3 J / (kg·℃), the highest temperature of the chip cannot exceed 110℃, then 1kg aluminum alloy can absorb 44KJ of heat from 60-110℃. However, 1kg of phase change material can absorb 200-300KJ, so in the research on the heat dissipation of high-power, short-time missile-borne electronic devices, phase change cold plates play an increasingly important role due to their advantages such as high heat storage density, fast heat absorption efficiency and small size.

[0003] Solid-liquid phase change materials are divided into organic phase change materials, inorganic phase change materials and eutectic phase change materials. The working principle is to use the heat absorption from solid to liquid to dissipate heat for the device. However, in the actual application scenarios of cold plates, traditional solid-liquid phase change materials will leak due to unqualified welding quality, bumps and other reasons, which seriously affects the normal operation of the device. In order to solve the leakage problem and improve the welding quality, it is very important to develop high enthalpy, high thermal conductivity, "micro liquid, macro solid" composite solid-solid phase change materials. However, the composite solid-solid phase change material is rigidly fitted with the metal shell during assembly, and there is air thermal resistance, which makes it impossible for the heat of the heating device to be transferred to the phase change material in time, resulting in the material failing to undergo or delaying phase change heat absorption, and ultimately causing the device to overheat and fail. Therefore, the assembly and application of composite solid-solid phase change materials in phase change cold plates is also a difficult problem.

[0004] In addition, for microelectronic devices, the uneven distribution of power density leads to the appearance of local hot spots, which eventually causes the device to fail. This is reflected in the uneven utilization of phase change materials in various regions on the phase change cold plate, and the heat absorption effect of the filled phase change material cannot be fully exerted. Therefore, how to design the phase change cold plate should be combined with the application scenario to select the type and layout of the composite solid-solid phase change material, ensure the filling amount of the phase change material, and consider the utilization rate of the phase change material. It is not possible to simply fill a single phase change material in the cavity. This is the problem to be solved by the utility model. Summary of the invention

[0005] The technical problem to be solved by the utility model is to provide a phase change cold plate with enhanced heat conduction, taking into account the overall thermal conductivity and heat storage capacity of the phase change cold plate, solving the internal air thermal resistance, solving the local hot spot problem, improving the overall performance of the phase change cold plate, and ensuring that the phase change cold plate meets the device temperature control requirements.

[0006] In order to solve the above technical problems, the technical solution adopted by the utility model is:

[0007] A phase change cold plate for enhancing heat conduction comprises a shell, a cover plate and a phase change material, wherein the shell and the cover plate form a closed cavity filled with the phase change material; specifically, the shell and the cover plate are welded into a closed cavity by vacuum brazing, stir friction welding or the like;

[0008] The outer surface of the phase change cold plate is provided with a slot, a pit or a boss, which is used to adapt to the heat-generating electronic components, and the heat-generating electronic components and the phase change cold plate are in close contact with each other. Specifically, the outer surface of the phase change cold plate can be provided with a slot (pit or boss) in combination with the layout structure of the heat-generating electronic components in the actual application scenario to ensure that the heat-generating components and the phase change cold plate are in close contact with each other, and the phase change cold plate can be assembled into the application system.

[0009] Preferably, corresponding matching slots are provided inside the shell and on the surface of the phase change material, and the slots are H-shaped, X-shaped or Z-shaped, so that the phase change material is in close contact with the metal shell, reducing the air thermal resistance and enhancing the overall thermal conductivity of the phase change cold plate. Composite solid-solid phase change materials can effectively solve the leakage problem of phase change cold plates, and can be formed by molding, extrusion, 3D printing and other molding methods to ensure that the heat storage per unit volume is close to that of solid-liquid phase change materials. The number of slot layouts can be determined according to the size of the phase change material. Generally, a corresponding slot can be set on an area of ​​10*10mm.

[0010] The phase change cold plate can simulate the actual use environment of the phase change cold plate through simulation software, and use the simulation results to adjust the type and layout of the composite solid-solid phase change material to ensure that it meets the device temperature control requirements.

[0011] For example, under the premise of meeting the total weight requirements of the cold plate, when the simulation results show that the high-power chip is overheated, the temperature of the low-power chip is not high, and the utilization rate of the phase change material below is not high: (1) Consider filling the area below the high-power chip with metal foam solid-solid phase change material, with a thermal conductivity greater than 30W / (mK); (2) Consider setting fins inside the cavity below the high-power chip and inserting the composite solid-solid phase change material into the fins; (3) Consider adding heat pipes to the cold plate below the high-power chip. The above measures can improve the local thermal conductivity below the high-power chip, which is conducive to transferring the heat accumulated here to other phase change materials that are not fully utilized in time as soon as possible, thereby improving the local hot spot problem.

[0012] Preferably, the shell is made of aluminum alloy, copper or magnesium alloy, and the shell thickness is greater than or equal to 1 mm.

[0013] Preferably, the phase change material is a composite solid-solid phase change material formed by silica-based, polymer-cured, expanded graphite-based, bentonite-based, and metal foam-based. In addition, the phase change material includes but is not limited to a composite solid-solid phase change material disclosed in CN115558468 A involving a high thermal conductivity liquid-solid phase change energy storage material and a preparation method thereof. The composite solid-solid phase change material can effectively solve the problem of liquid leakage of the phase change cold plate, and can ensure that the heat storage per unit volume is close to that of the solid-liquid phase change material through molding methods such as molding, extrusion, and 3D printing.

[0014] The utility model can achieve the following beneficial effects:

[0015] Solve the thermal resistance between the composite solid-solid phase change material and the air inside the metal shell, improve the local overheating problem of high-power devices, enhance the overall thermal conductivity and heat storage capacity of the cold plate, and ensure that the phase change cold plate meets the temperature control requirements of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The utility model is further described below in conjunction with the accompanying drawings and embodiments:

[0017] Figure 1 This is a schematic diagram of the appearance of the utility model (close to the heat source side);

[0018] Figure 2 This is a schematic diagram of the joint between the internal shell and the phase change material of the utility model;

[0019] Figure 3 The temperature rise curves of the chips of different types of phase change cold plates of the utility model at an ambient temperature of 80°C.

[0020] In the figure: 1——indicates a card slot;

[0021] 2——Indicates 2 card slots;

[0022] 3——indicates 3 card slots;

[0023] 4——indicates 4 card slots;

[0024] 5——Indicates the upper cover of the shell;

[0025] 6——Indicates the lower cover of the shell;

[0026] 7——Indicates phase change material. DETAILED DESCRIPTION

[0027] The preferred solution is Figures 1 to 3As shown, in order to solve the problems of low heat dissipation efficiency and uneven heat dissipation of traditional cold plates (metal heat sinks), the utility model proposes a phase change cold plate with enhanced heat conduction, and the specific structure is as follows:

[0028] It includes a shell, a cover plate and a phase change material. The shell and the cover plate form a closed cavity filled with the phase change material. The outer surface of the phase change cold plate is provided with a slot, a pit or a boss. The slot, the pit or the boss is used to adapt to the heat-generating electronic components. The heat-generating electronic components are in close contact with the phase change cold plate.

[0029] (1) It is made of aluminum alloy (AL-6061 can be selected), the composite solid-solid phase change material is filled into the cavity, and then the cavity and the cover are welded into a whole by stir friction welding technology.

[0030] (2) A slot (pit or boss) is set on the outer surface of the phase change cold plate close to the heat source to ensure that the heat-generating components and the phase change cold plate are in close contact with each other and that the phase change cold plate can be assembled into the application system. The power distribution is as follows: Figure 1 In the middle, the chip heating power corresponding to 1 is 40w. Figure 1 The corresponding chip heating power at locations 2, 3, and 4 is 5W.

[0031] (3) Corresponding matching slots are set inside the metal shell and on the surface of the phase change material. The slots are H-shaped, and one slot is set on each 10*10mm area. Figure 2 As shown, the phase change material is in close contact with the metal shell, the air thermal resistance is reduced, and the overall thermal conductivity of the phase change cold plate is enhanced.

[0032] (4) Select an 86°C composite solid-solid phase change material that is 80°C higher than the ambient temperature.

[0033] (5) Since the high-power chips of the phase change cold plate are concentrated Figure 1 Therefore, metal foam solid-solid phase change material is filled in the area below point 1 to enhance the local thermal conductivity, which is beneficial to transfer the heat accumulated here to other phase change materials that are not fully utilized in time as soon as possible, so as to improve the local hot spot problem.

[0034] In order to verify the excellent performance of the phase change cold plate (named as cold plate 3) of the utility model, the thermal control performance was compared with that of pure aluminum plate, cold plate 1 and cold plate 2. Figure 1 The temperature of a 40W high-power chip at 110°C in the middle shows the temperature control time of each cold plate. The longer the temperature control time, the better the temperature control performance of the cold plate. The differences in the design of each cold plate are as follows:

[0035] Cold plate 1: composite solid-solid phase change material + metal shell.

[0036] Cold plate 2: composite solid-solid phase change material + metal shell + corresponding slots between the shell and the material.

[0037] Cold plate 3: composite solid-solid phase change material + metal shell + corresponding slots between the shell and the material + metal foam is filled in the area below the high-power chip to shape the solid-solid phase change material.

[0038] Test process: After keeping the temperature at 80℃ for 2h, when the temperature of the entire cold plate reaches 80℃, turn on the heat source and record Figure 1 The temperature of one chip.

[0039] Test results: pure aluminum plate and 3 cold plates Figure 1 The chip temperature rise curve at 1 is as follows Figure 3 , the temperature control time corresponding to the temperature rise to 110℃ is as follows:

[0040]

[0041] The analysis is as follows:

[0042] 1. Comparing the data of cold plate 1, cold plate 2 and pure aluminum plate, it can be seen that cold plate 1 has no slot between the metal shell and the phase change material, and there is air thermal resistance, which leads to no phase change in the phase change material during the test, and no phase change platform is generated, making its temperature control performance worse than that of pure aluminum plate. After adding a slot between the metal shell and the phase change material of cold plate 2, the air thermal resistance is reduced, making its temperature control performance better than that of pure aluminum plate.

[0043] 2. The utility model provides a phase change cold plate (cold plate 3) for enhancing heat conduction, with corresponding slots added between the shell and the material, and fills the area below the high-power chip with metal foam-shaped solid-solid phase change material, which effectively solves the thermal resistance between the composite solid-solid phase change material and the air inside the metal shell, improves the problem of local overheating of high-power devices, enhances the overall thermal conductivity and heat storage capacity of the cold plate, and ensures that the phase change cold plate meets the temperature control requirements of the device.

[0044] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A phase change cold plate for enhancing heat conduction, characterized in that: It includes a shell, a cover plate and a phase change material. The shell and the cover plate form a closed cavity filled with the phase change material. The outer surface of the phase change cold plate is provided with a slot, a pit or a boss. The slot, the pit or the boss is used to adapt to the heat-generating electronic components. The heat-generating electronic components are in close contact with the phase change cold plate.

2. A phase change cold plate with enhanced heat conduction according to claim 1, characterized in that: Corresponding matching slots are arranged inside the shell and on the surface of the phase change material. The slots are H-shaped, X-shaped or Z-shaped, so that the phase change material is in close contact with the metal shell, reducing the air thermal resistance and enhancing the overall thermal conductivity of the phase change cold plate.

3. A phase change cold plate with enhanced heat conduction according to claim 2, characterized in that: The shell is made of aluminum alloy, copper or magnesium alloy, and the shell thickness is greater than or equal to 1 mm.

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