Liquid metal passive self-driven thermal control system and method based on thermoelectric effect and magnetic field cooperation

Abstract

The invention discloses a liquid metal passive self-driven thermal control system and method based on thermoelectric effect and magnetic field cooperation, and belongs to the technical field of thermal control of electronic equipment. The two end faces of the thermoelectric module are tightly attached to the heating device and the cold plate respectively. The thermoelectric module comprises a ceramic substrate, and an electrode is electroplated on the surface of the ceramic substrate; between the ceramic substrates, the thermoelectric crystal grains are electrically connected in series and thermally connected in parallel to form a columnar array, the columnar array is welded on the electrodes, and an external wire is welded. The electrode is embedded into the wall surface of the cold plate and connected with the output end of the thermoelectric module, the potential difference generated by the thermoelectric module is applied to the electrode, and current is formed in the liquid metal; the liquid metal working medium is sealed in the cold plate, the electrified liquid metal working medium is subjected to the effect of Lorentz force under the effect of an external magnetic field, liquid metal is driven to flow in one direction, and heat exchange is enhanced. Reliable technical support is provided for efficient heat dissipation of the electronic equipment.

Description

Technical Field

[0001] This invention relates to the field of thermal control technology for electronic devices, and more specifically, to a self-driven thermal control system and method for liquid metal based on thermoelectric effect and magnetic field synergy. Background Technology

[0002] With the rapid development of very large-scale integrated circuits, the heat flux density per unit area of ​​circuit chips has increased dramatically, posing a severe challenge to the effective cooling and reliable operation of electronic components. This is especially true for avionics equipment and components, which operate in harsh environments, have high reliability requirements, and face stringent limitations on size and weight, placing even stricter demands on circuit integration and thermal control solutions.

[0003] To address the heat dissipation challenges of packaged electronic chips, researchers have proposed integrating liquid metal into the chip to enhance heat transfer. Common driving methods for liquid metal cooling include magnetohydrodynamics, peristaltic pumps, and electro-floating pumps. However, these conventional methods require complex circuitry and auxiliary energy input, resulting in large and complex cooling systems. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a self-driven liquid metal thermal control system and method based on thermoelectric effect and magnetic field synergy. It can realize the self-flowing drive of liquid metal in a sealed cold plate. The thermal control system has a simple structure and significantly reduces the size of the thermal control system. At the same time, by adjusting the strength of the external magnetic field, the heat transfer rate can be accurately and effectively adjusted, providing reliable technical support for the efficient heat dissipation of electronic devices.

[0005] The objective of this invention is achieved through the following solution: A self-driven thermal control system based on the thermoelectric effect and magnetic field synergy using liquid metal includes a thermoelectric module, a cold plate, and electrodes. The two end faces of the thermoelectric module are respectively attached to a heating element and the cold plate. The working fluid inside the cold plate is liquid metal. The system utilizes the temperature difference Δ between the heating element and the cold plate. T A potential difference Δ is generated V=S× △ T , S The Seebeck coefficient of the thermoelectric material; The thermoelectric module includes a ceramic substrate, on which electrodes are electroplated; between the ceramic substrates, N-type thermoelectric grains and P-type thermoelectric grains are connected in series electrically and in parallel thermally to form a columnar array, and the corresponding thermoelectric grains are welded to the electrodes and external wires are welded. The electrodes are embedded in the wall of the cold plate and connected to the output terminal of the thermoelectric module. The potential difference generated by the thermoelectric module is applied to the electrodes, forming a current density in the liquid metal. J=σ× △ V / d , σ The conductivity of the liquid metal working fluid, d The vertical distance between the two electrodes; Liquid metal working fluid is sealed inside a cold plate, and an external magnetic field is applied. B A liquid metallic working fluid carrying current perpendicular to the direction of the current experiences a Lorentz force under the influence of an external magnetic field. F = J × B The Lorentz force drives the unidirectional flow of liquid metal, enhancing heat transfer; the high-speed flowing liquid metal transfers the heat generated by the heating device to the cold plate through convection heat transfer. Convection heat transfer continuously removes heat from the hot end, while the cold plate dissipates heat, maintaining Δ. T Stable, the system enters dynamic equilibrium when the heat transfer rate equals the heating power of the heating device.

[0006] Furthermore, the ceramic substrate is an AlN ceramic substrate; the N-type thermoelectric grain is a Be2Te3 thermoelectric grain; and the P-type thermoelectric grain is an Sb2Te3 thermoelectric grain.

[0007] Furthermore, the liquid metal is a GaInSn alloy.

[0008] Furthermore, the electrode is a tapered electrode made of molybdenum.

[0009] Furthermore, the cold plate is made of aluminum and has heat dissipation fins both inside and outside.

[0010] Furthermore, the external magnetic field is achieved by arranging two square NdFeB material permanent magnets facing each other.

[0011] A method for operating a self-driven, liquid metal thermal control system based on thermoelectric effect and magnetic field synergy, comprising the following steps: Step 1, Heat Source Activation: When the controlled heating device operates, it generates heat, causing the surface temperature of the electronic device to rise to a certain level. T h The cold plate exchanges heat with the ambient temperature through heat dissipation fins to maintain the temperature. T c This forms an initial temperature difference Δ T 0 =T h - T c ; Step 2, Thermoelectric Conversion: The thermoelectric module, tightly bonded between the heating element and the cold plate, directly converts the temperature difference into an electrical potential difference: △ V=S× △ T , S The Seebeck coefficient of the thermoelectric material is used, and the potential is applied to the liquid metal circuit through a molybdenum electrode. Step 3, Electromagnetic Drive: A potential difference is applied to the electrode pairs at both ends of the sealed flow channel, generating a current density in the liquid metal. J=σ× △ V / d , σ The conductivity of the liquid metal working fluid, d The distance between the two electrodes is the perpendicular distance; the applied magnetic field B is perpendicular to the direction of the current, and the current-carrying liquid metal working fluid is subjected to a Lorentz force under the action of the applied magnetic field. F = J × B The Lorentz force drives the unidirectional flow of liquid metal. Step 4, Heat Transfer: The high-speed flowing liquid metal transfers the heat generated by the heating device to the cold plate through convection heat transfer, thus enhancing heat transfer; the cold plate exchanges heat with the environment through heat dissipation fins. Step 5, Positive Feedback Cycle: Enhanced heat exchange ensures that heat is continuously removed from the hot end, while the cold plate efficiently dissipates heat, maintaining Δ T Stable, the system enters dynamic equilibrium when the heat transfer rate equals the heating power of the heating device.

[0012] The beneficial effects of this invention include: This invention solves the problems of complex structure and large thermal control system volume in traditional cold plate flow driving methods. It designs a self-driven thermal control system and method for liquid metal based on thermoelectric effect and magnetic field synergy. By applying an external non-uniform magnetic field, the thermoelectric effect is generated by the temperature difference between the heating element of the electronic device and the cold plate, thus driving the flow of liquid metal. This achieves self-driven flow within a sealed cold plate. Compared with commonly used driving methods, the thermal control system has a simpler structure and a significantly smaller volume. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a diagram of a self-driven thermal control system for liquid metal based on the synergy of thermoelectric effect and magnetic field in an embodiment of the present invention; Figure 2 This is an internal cross-sectional view of the liquid metal self-driven thermal control system based on the synergy of thermoelectric effect and magnetic field in an embodiment of the present invention; Figure 3 This is a cross-sectional view of the cold plate in an embodiment of the present invention; Figure 4This is a diagram showing the internal current, magnetic field, and liquid metal flow direction in an embodiment of the present invention. In the diagram, 1. Controlled heating device; 2. Thermoelectric module; 3. Cold plate; 4. Permanent magnet; 5. Ceramic substrate; 6. Copper electrode; 7. N-type thermoelectric grain; 8. P-type thermoelectric grain; 9. Heat sink fins; 10. Liquid metal; 11. Electrode; 12. Current direction; 13. Magnetic field direction; 14. Liquid metal flow direction. Detailed Implementation

[0015] All features disclosed in all embodiments of this specification, or steps in all methods or processes implied in the disclosure, may be combined and / or extended or replaced in any way, except for mutually exclusive features and / or steps.

[0016] In a preferred embodiment, as a first aspect of the present invention, a self-driven thermal control system for liquid metal based on the synergy of thermoelectric effect and magnetic field is provided, comprising: a thermoelectric module 2, an electrode pair, liquid metal 10, an external magnetic field, and a sealed cold plate 3, wherein the two end faces of the thermoelectric module 2 are in contact with the controlled heating device 1 and the cold plate 3, respectively, and the electrode pair includes electrodes 11, such as... Figure 1 As shown.

[0017] The two ends of the thermoelectric module 2 are respectively in close contact with the heating element and the cold plate 3 (the internal working fluid is liquid metal), utilizing the temperature difference Δ between the heating element and the cold plate 3. T A potential difference Δ is generated V=S× △ T ( S , where Seebeck coefficient is the thermoelectric material coefficient, in µV / K. More specifically, the thermoelectric module 2 of this invention is based on a ceramic substrate 5 (AlN ceramic substrate can be used), with copper electrodes 6 electroplated on the surface of the ceramic substrate 5. N-type thermoelectric grains 7 (Be2Te3) and P-type thermoelectric grains 8 (Sb2Te3) are used. The N-type and P-type thermoelectric grains are electrically connected in series and thermally connected in parallel to form a 7×7 columnar array through vacuum hot pressing. Then, a low-melting-point solder (135°C) is used to solder the thermoelectric grains onto the copper electrodes. External wires are soldered on, and finally, epoxy resin is used for potting. Figure 2 As shown.

[0018] The electrode pair is embedded in the wall of the sealed cold plate 3 and connected to the output end of the thermoelectric module 2. The potential difference generated by the thermoelectric module 2 is applied to the electrode pair, forming a current density in the liquid metal 10 (GaInSn alloy). J=σ× △ V / d ( σ The conductivity of the liquid metal working fluid, d (This refers to the vertical distance between the two electrodes). More specifically, the electrode pair of the present invention uses a tapered electrode made of molybdenum material, such as... Figure 2 As shown.

[0019] The liquid metal working fluid is sealed inside the cold plate 3, and an external magnetic field is applied. B A liquid metallic working fluid carrying current perpendicular to the direction of the current experiences a Lorentz force under the influence of an external magnetic field. F = J × B The Lorentz force drives the unidirectional flow of liquid metal 10, enhancing heat transfer. The liquid working fluid can be a GaInSn alloy, sealed inside the cold plate 3, such as... Figure 3 As shown.

[0020] The high-speed flowing liquid metal 10 transfers the heat generated by the heating device to the cold plate 3 through convection heat transfer. The convection heat transfer continuously removes heat from the hot end, while the cold plate 3 efficiently dissipates heat, maintaining the temperature difference Δ. T Stable, the system enters dynamic equilibrium when the heat transfer rate equals the heating power of the heating device. In a more specific design, the cold plate 3 can be made of aluminum, with heat dissipation fins 9 both inside and out, such as... Figure 3 As shown.

[0021] The external magnetic field is achieved by arranging two square NdFeB permanent magnets 4 facing each other, with each magnet measuring 20×20×1 mm. Figure 4 In the diagram, 12 indicates the direction of the current, 13 indicates the direction of the magnetic field (perpendicular to the paper and outwards, perpendicular to the direction of the current), and 14 indicates the direction of the liquid metal flow.

[0022] As a second aspect of the present invention, a method for operating a self-driven thermal control system of liquid metal based on the synergy of thermoelectric effect and magnetic field is provided, comprising the steps of: Step 1, Heat Source Activation: When the electronic device's heating element (controlled heating element 1) is working, it generates heat, causing the surface temperature of the electronic device to rise to a certain level. T h (Hot end temperature), the cold plate 3 exchanges heat with the ambient temperature through heat dissipation fins to maintain the temperature. T c , forming an initial temperature difference Δ T 0 =T h - T c ,like Figure 2 As shown.

[0023] Step 2, Thermoelectric Conversion: The thermoelectric module (Bi2Te3-based) tightly bonded between the heating element and the cold plate 3 directly converts the temperature difference into an electric potential difference: △ V=S× △ T ( S (This refers to the Seebeck coefficient of the thermoelectric material, in μV / K). An electric potential is applied to the liquid metal circuit through a molybdenum electrode, such as... Figure 4 As shown.

[0024] Step 3, Electromagnetic Drive: A potential difference is applied to the electrode pairs at both ends of the sealed flow channel, forming a current density in the liquid metal (GaInSn alloy). J=σ× △ V / d ( σ The conductivity of the liquid metal working fluid, d (where B is the perpendicular distance between the two electrodes). The applied magnetic field B is perpendicular to the direction of the current. The liquid metal working fluid carrying the current experiences a Lorentz force under the action of the applied magnetic field. F = J × B The Lorentz force drives the unidirectional flow of liquid metal, such as... Figure 4 As shown.

[0025] Step 4, Heat Transfer: The high-speed flowing liquid metal transfers the heat generated by the heat-generating device to the cold plate through convection heat transfer, enhancing heat exchange. The cold plate 3 exchanges heat with the environment through heat dissipation fins.

[0026] Step 5, Positive Feedback Cycle: Enhanced heat exchange ensures that heat is continuously removed from the hot end, while the cold plate efficiently dissipates heat, maintaining Δ T Stable, the system enters dynamic equilibrium when the heat transfer rate equals the heating power of the heating device.

[0027] All parts not covered in this invention are the same as or can be implemented using existing technologies.

[0028] The above technical solution is only one embodiment of the present invention. For those skilled in the art, based on the application methods and principles disclosed in the present invention, it is easy to make various types of improvements or modifications, and not limited to the methods described in the above specific embodiments of the present invention. Therefore, the methods described above are only preferred and are not restrictive.

[0029] In addition to the examples above, other embodiments may be obtained by those skilled in the art based on the above disclosure or by making modifications using knowledge or technology in related fields. The features of each embodiment may be interchanged or replaced. Modifications and changes made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A liquid metal passive self-driven thermal control system based on thermoelectric effect and magnetic field synergy, characterized in that, The application relates to a thermoelectric module, a cold plate and an electrode; wherein the two end faces of the thermoelectric module are respectively close to a heating device and the cold plate, the internal working medium of the cold plate is liquid metal, and the temperature difference Delta T between the heating device and the cold plate is utilized to generate an electric potential difference Delta V T The electric potential difference Delta V is generated V=Sx Delta T T , S The application relates to a thermoelectric module, a cold plate and an electrode; wherein the two end faces of the thermoelectric module are respectively close to a heating device and the cold plate, the internal working medium of the cold plate is liquid metal, and the temperature difference Delta T between the heating device and the cold plate is utilized to generate an electric potential difference Delta V The thermoelectric module comprises ceramic substrates, and electrodes are electroplated on the surfaces of the ceramic substrates; N-type thermoelectric grains and P-type thermoelectric grains are arranged into a columnar array through electrical series connection and thermal parallel connection between the ceramic substrates, and the corresponding thermoelectric grains are welded on the electrodes, and external connecting wires are welded; The electrodes are embedded in the wall of the cold plate and are connected to the output terminals of the thermoelectric module. The potential difference generated by the thermoelectric module is applied to the electrodes, forming an electric current density in the liquid metal J=σx △ V / d , σ is the electrical conductivity of the liquid metal working medium, d is the vertical distance between the two electrodes; Liquid metal working substance is sealed in the cold plate, and an external magnetic field is applied B The liquid metal working substance is perpendicular to the current direction, and the liquid metal working substance is subjected to Lorentz force under the action of the external magnetic field F = J × B The Lorentz force drives the one-way flow of liquid metal, and strengthens the heat exchange; the high-speed flowing liquid metal transfers the heat generated by the heating device to the cold plate through convective heat exchange, and the convective heat exchange makes the heat at the hot end be continuously taken away, and the cold plate dissipates heat, thereby maintaining the stability of △ T When the heat transfer rate is equal to the heating power of the heating device, the system enters dynamic balance.

2. The liquid metal passive self-driven thermal control system based on thermoelectric effect and magnetic field synergy according to claim 1, characterized in that, The ceramic substrates are AlN ceramic substrates; the N-type thermoelectric grains are Be2Te3 thermoelectric grains; and the P-type thermoelectric grains are Sb2Te3 thermoelectric grains.

3. The liquid metal passive self-driven thermal control system based on thermoelectric effect and magnetic field synergy according to claim 1, characterized in that, The liquid metal is a GaInSn alloy.

4. The liquid metal passive self-driven thermal control system based on thermoelectric effect and magnetic field synergy according to claim 1, characterized in that, The electrodes are molybdenum material conical electrodes.

5. The liquid metal passive self-driven thermal control system based on thermoelectric effect and magnetic field synergy according to claim 1, characterized in that, The cold plate is an aluminum cold plate, and has heat dissipation fins inside and outside.

6. The liquid-metal passive self-driven thermal control system based on thermoelectric effect and magnetic field synergy according to claim 1, characterized in that, The external magnetic field is arranged in a square shape by two square NdFeB permanent magnets.

7. A method for operating a liquid metal passive self-driven thermal control system based on the thermoelectric effect and magnetic field synergy, characterized in that, The liquid metal passive self-driven thermal control system based on thermoelectric effect and magnetic field synergy according to any one of claims 1-6 comprises the following steps: Step 1, heat source start: the controlled heating device works to produce heat, so that the surface temperature of the electronic device rises to T h , the cold plate exchanges heat with the environment temperature through the heat dissipation fins, and maintains the temperature T c , forming an initial temperature difference Δ T 0 =T h - T c ; Step 2, thermoelectric conversion: The thermoelectric module, which is tightly fitted between the heat generating device and the cold plate, directly converts the temperature difference into a potential difference: ΔV V=Sx ΔV T , S is the Seebeck coefficient of the thermoelectric material, and the potential is applied to the liquid metal circuit through the molybdenum electrode; Step 3, electromagnetic driving: a potential difference is applied to the electrode pair at both ends of the sealed flow channel, forming a current density in the liquid metal J=σx △ V / d , σ is the electrical conductivity of the liquid metal working medium, d is the vertical distance between the two electrodes; the applied magnetic field B is perpendicular to the current direction, and the electrically conductive liquid metal working medium is subjected to the Lorentz force under the action of the applied magnetic field F = J × B , the Lorentz force drives the one-way flow of the liquid metal; Step 4, heat transfer: the high-speed flowing liquid metal transfers the heat generated by the heat generating device to the cold plate through convective heat exchange to strengthen heat exchange; the cold plate exchanges heat with the environment through the heat dissipation fins; Step 5, positive feedback loop: Reinforcing heat exchange makes the heat at the hot end continue to be taken away, while the cold plate dissipates heat efficiently, maintaining ΔT T Stable, when the heat transfer rate is equal to the heat generation power of the heat generating device, the system enters dynamic balance.

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