Thermal switch using air bag actuator under immersion cooling

Abstract

A thermal switch applying an air bag actuator under immersion cooling comprises a heat source, the heat source is clamped between two heat insulation plates to form a sandwich shape, the air bag actuator is further arranged between the heat source and the heat insulation plates, and the two heat insulation plates are connected through a spring. The air bag actuator is a core component of the thermal switch, and liquid with a specific boiling point is injected before the air bag is sealed. When the temperature exceeds the boiling point of the liquid, the air bag actuator overcomes the pulling force of the return spring and pushes the heat insulation plate away from the surface of the heat source. The cooling liquid is directly contacted with the surface of the heat source; the thermal resistance of the heat source and the cooling liquid is reduced, the thermal switch is turned on, and the heat of the heat source can be transferred into the cooling liquid to reduce the temperature of the heat source; the switch has the advantages of simple structure, extremely low failure rate, high switch ratio and light weight.

Description

Technical Field

[0001] This invention belongs to the field of thermal management technology, specifically relating to a thermal switch for an airbag actuator used in immersion cooling. Background Technology

[0002] From microscopic electronic chips to macroscopic large-scale industrial equipment, effective heat control and management directly affect equipment performance, reliability, and lifespan. Traditional heat conduction materials and methods cannot flexibly cope with rapid changes and complex distributions of heat. Thermal switches, as a novel thermal management technology, offer a unique ability to automatically switch heat conduction and blocking based on changes in physical quantities such as temperature. This provides a completely new approach and method for solving these thermal management challenges and is gradually becoming an indispensable key component of thermal management systems across various fields.

[0003] The thermal switch actuator is a key component of a thermal switch system. Its main function is to trigger the thermal switch to switch between on and off states based on specific physical signals or changes in environmental conditions, thereby achieving precise control of heat transfer. The most common type is the spring actuator based on shape memory alloys. When the temperature changes, the spring extends or compresses, thus actuating the contacts of the thermal switch. This type of thermal switch has a simple structure and can withstand considerable force, but the use of shape memory alloys increases its cost, limiting its widespread application.

[0004] Bimetallic actuators are also quite common. They consist of two metal sheets with different coefficients of thermal expansion bonded together. When the temperature changes, the bimetallic sheet bends and deforms due to the different expansion rates of the two metal layers. This deformation can be used to drive contacts, causing the thermal switch to close or open. This type of actuator is simple in structure, inexpensive, and reliable in operation, but its response speed is relatively slow and its control precision is limited.

[0005] A paraffin-based phase-change thermal switch is a thermal management device that utilizes the unique phase-change properties of paraffin to control the on / off state of heat. Paraffin exhibits a significant solid-liquid phase-change characteristic, accompanied by a substantial volume change during the phase-change process. When paraffin is in a solid state, the internal structure or material contact state of the thermal switch is unfavorable for heat transfer, and the thermal switch is in an off state. However, when the temperature rises and the paraffin melts into a liquid state, the force generated by the volume expansion can drive certain components to move, changing the internal structure of the thermal switch, opening the heat conduction path, and allowing heat to be transferred. The phase-change process of paraffin requires a certain amount of time to complete, especially with a large volume, resulting in a relatively slow response speed and a large mass of the thermal switch.

[0006] Patent application CN202021484296.6 discloses a battery temperature control switch that uses the phase change of paraffin to drive the movement of a heat-conducting slider to achieve the function of heat transfer and disconnection. The large heat capacity of paraffin causes the invention to have a slow switching between the two states of heat transfer and heat insulation. Summary of the Invention

[0007] In order to overcome the shortcomings of the prior art, the present invention aims to provide a thermal switch using an airbag actuator under immersion cooling. The airbag actuator is filled with a low-boiling-point liquid, which can shrink in volume at low temperatures and expand in volume at high temperatures, thereby adjusting the thermal resistance. In this process, ideal thermal function can be obtained without applying additional control logic. It has the characteristics of being lightweight, low cost, and superior performance.

[0008] To achieve the above objectives, the present invention employs the following technical solution:

[0009] A thermal switch for use with an airbag actuator under immersion cooling includes a heat source 1 sandwiched between two heat insulation plates 3 in a sandwich shape. An airbag actuator 2 is also provided between the heat source 1 and the heat insulation plates 3. The two heat insulation plates 3 are connected by a spring 4.

[0010] The heat source 1 includes a battery and a circuit board.

[0011] The airbag actuator 2 is made of two layers of aluminum-plastic film sealed around the edges.

[0012] The airbag actuator 2 is filled with a low-boiling-point liquid.

[0013] The low-boiling-point liquid is an electronic fluorinated liquid, including Novec7000.

[0014] The surface of the heat insulation board 3 is covered with heat insulation cotton.

[0015] The mathematical relationship between the saturated vapor pressure and temperature of the electronic fluorinated liquid satisfies:

[0016]

[0017] Where T is the temperature of the low-boiling-point liquid, and P Novec7000 It is the saturated vapor pressure of the electronic fluorinated liquid.

[0018] The present invention has the following beneficial technical effects:

[0019] 1. The airbag actuator 2 in this invention is filled with a low-boiling-point liquid, which can shrink in volume at low temperatures and expand in volume at high temperatures. The thermal switch relies on the airbag actuator 2 and the return spring 4 to switch between heat transfer and heat insulation, and can realize the thermal management functions of low-temperature insulation and high-temperature heat dissipation.

[0020] 2. The airbag actuator 2 in this invention is made of aluminum-plastic film welding, with a sufficient amount of low-boiling-point liquid injected before welding. This airbag actuator weighs only a few grams, which can reduce the overall weight of the thermal switch.

[0021] 3. In this invention, the thermal switch provides good insulation when the insulation cotton covers the heat source surface when closed. When the thermal switch is turned on, the airbag actuator pushes the insulation plate away from the heat source surface, allowing the coolant to directly contact the heat source surface and thus achieve cooling. In both states described above, the thermal switch exhibits high thermal resistance at low temperatures and low thermal resistance at high temperatures, enabling a non-linear thermal management strategy.

[0022] In summary, this invention has a simple structure, an extremely low failure rate, and is a thermal switch with a high on / off ratio and high lightweight design. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0024] Figure 2 This is a front view of the overall structure of the present invention (the heat insulation plate is in close contact with the heat source).

[0025] Figure 3 This is a side view of the overall structure of the present invention (the heat insulation plate is away from the heat source).

[0026] Figure 4 The relationship curve between the present invention and the corresponding curve is as follows:

[0027] Explanation of reference numerals in the attached figures:

[0028] 1-Heat source, 2-Airbag actuator, 3-Heat insulation plate, 4-Return spring, 5-Coolant. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings.

[0030] like Figures 1 to 3 As shown, a thermal switch with an airbag actuator for immersion cooling includes a heat source 1 sandwiched between two heat insulation plates 3 in a sandwich shape. An airbag actuator 2 is also provided between the heat source 1 and the heat insulation plates 3. The two heat insulation plates 3 are connected by a spring 4.

[0031] The airbag actuator 2 contains a low-boiling-point liquid. The airbag actuator 2 is the core component of the thermal switch; a liquid with a specific boiling point is injected before the airbag is sealed. When the temperature exceeds the liquid's boiling point, the airbag actuator 2 overcomes the tension of the return spring 4, pushing the heat insulation plate 3 away from the surface of the heat source 1. At this time, the coolant 5 is in direct contact with the surface of the heat source 1. The thermal resistance between the heat source 1 and the coolant 5 decreases, the thermal switch is in the open state, and the heat from the heat source 2 can be transferred to the coolant 5, thereby reducing the temperature of the heat source 1.

[0032] The heat source 1 includes a battery and a circuit board.

[0033] The airbag actuator 2 is made of two layers of aluminum-plastic film sealed around the edges.

[0034] The airbag actuator 2 is filled with a low-boiling-point liquid.

[0035] The low-boiling-point liquid is an electronic fluorinated liquid, including Novec7000.

[0036] The surface of the heat insulation board 3 is covered with heat insulation cotton.

[0037] The heat source 1 is immersed in the coolant 5. The heat insulation plate 3 is in close contact with the heat source 1 at low temperatures to prevent heat loss; at high temperatures, it is driven away from the heat source 1 by the airbag actuator 2, and the heat is transferred to the coolant 5.

[0038] like Figure 4 The mathematical relationship between the saturated vapor pressure and temperature of the electronic fluorinated liquid satisfies:

[0039]

[0040] Where T is the temperature of the low-boiling-point liquid, and P Novec7000 It is the saturated vapor pressure of the electronic fluorinated liquid.

[0041] The working principle of this invention is as follows: Before sealing, the airbag actuator 2 is injected with a liquid of a specific boiling point. When the temperature exceeds the boiling point of this liquid, the liquid in the airbag actuator 2 rapidly vaporizes, and the airbag actuator 2 overcomes the tension of the return spring 4, pushing the heat insulation plate 3 away from the surface of the heat source 1. At this time, the thermal resistance between the surface of the heat source 1 and the coolant 5 is small, and the thermal switch is in the open state. When the temperature is lower than the liquid sealed inside the airbag actuator 2, the airbag actuator 2 rapidly contracts. At this time, the heat insulation plate 3 is pulled by the return spring 4 to press tightly against the surface of the heat source 1, and the thermal resistance between the heat source 1 and the coolant 5 increases significantly, and the thermal switch is in the closed state.

[0042] The thermal switch of the airbag actuator 2 in this invention can automatically sense temperature changes and adjust thermal resistance, intelligently regulating the temperature of the heat source. Ideal thermal functionality can be achieved without applying additional control logic. The specific boiling point liquid used in the airbag actuator can be any substance capable of undergoing a gas-liquid phase change; the type of liquid injected into the airbag actuator depends on the required switching temperature. The heat insulation plate in the thermal switch can be made of any material, as long as it possesses the required heat insulation function and structural strength. The coolant in the thermal switch can be any type of cooling medium, as long as it possesses the required cooling function.

[0043] The above description is only a basic embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. Improvements and modifications made without departing from the principle of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A thermal switch for an airbag actuator used in immersion cooling, comprising a heat source (1), characterized in that, The heat source (1) is sandwiched between two heat insulation plates (3) in a sandwich shape. An airbag actuator (2) is also provided between the heat source (1) and the heat insulation plates (3). The two heat insulation plates (3) are connected by a spring (4).

2. A thermal switch for use with an airbag actuator under immersion cooling according to claim 1, characterized in that, The heat source (1) includes a battery and a circuit board.

3. A thermal switch for use with an airbag actuator under immersion cooling according to claim 1, characterized in that, The airbag actuator (2) is made of two layers of aluminum-plastic film sealed around the edges.

4. A thermal switch for use with an airbag actuator under immersion cooling according to claim 1 or 3, characterized in that, The airbag actuator (2) is filled with a low-boiling-point liquid.

5. A thermal switch for use with an airbag actuator under immersion cooling according to claim 4, characterized in that, The low-boiling-point liquid is an electronic fluorinated liquid, including Novec7000.

6. A thermal switch for use with an airbag actuator under immersion cooling according to claim 1, characterized in that, The surface of the heat insulation board (3) is covered with heat insulation cotton.

7. A thermal switch for use with an airbag actuator under immersion cooling according to claim 4, characterized in that, The mathematical relationship between the saturated vapor pressure and temperature of the electronic fluorinated liquid satisfies: Where T is the temperature of the low-boiling-point liquid, and P Novec7000 It is the saturated vapor pressure of the electronic fluorinated liquid.

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