Electrostatically Actuated Thermal Switches

Abstract

The present invention discloses an electrostatically driven thermal switch, comprising a thermal switch upper pole, a thermal switch lower pole and a support body arranged between the thermal switch upper pole and the thermal switch lower pole; the thermal switch lower pole comprises a bottom substrate, a conductive lower electrode and a lower electrode plate arranged on the bottom substrate; the thermal switch upper pole comprises an upper electrode plate connected to one end of the support body away from the lower electrode plate, a conductive upper electrode connected to the upper electrode plate and a color-changing ink layer arranged on the conductive upper electrode; the bottom substrate, the conductive lower electrode and the lower electrode plate are all provided with a heat-conducting part. The present invention embeds a heat-conducting part on the bottom substrate, the conductive lower electrode and the lower electrode plate. When it is necessary to conduct heat to the device connected to the present invention, the heat-conducting part can efficiently transfer the heat of the device to the thermal switch upper pole, exchange heat with the ambient space in a radiation manner, and achieve the effect of heat dissipation. The conductive upper electrode is provided with a color-changing ink layer to enhance the radiation heat transfer capability of the thermal switch upper pole and improve the heat dissipation capability.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of thermal switches, and in particular to an electrostatically driven thermal switch. Background Art

[0002] A thermal switch is a device that achieves heat control by changing the thermal resistance of a heat conduction path. It plays the role of opening and closing in the heat path and is widely used in the thermal management of power electronic equipment, power devices, microelectronic chips, high-power engineering systems, etc. At present, a variety of thermal switches with different driving principles have been developed.

[0003] Electrostatically driven thermal switches have attracted the attention of many researchers due to their light weight, small size, low power consumption, simple operation and low cost. A typical electrostatically driven thermal switch consists of the following parts: the outermost layer is a heat dissipation film with high emissivity, the middle layer uses an insulating support structure to form the activity space of the heat dissipation film, and the bottom layer is a high thermal conductivity substrate with a low emissivity film on the surface (the high thermal conductivity substrate has good thermal contact with the heat source). When working, the electrostatic force controls the size of the contact area between the heat dissipation film and the substrate to realize the conversion of the heat exchange mode between thermal radiation and heat conduction between the two, and the thermal switch actively adjusts the heat dissipation power by changing the thermal resistance of the heat conduction channel. However, in the existing electrostatically driven thermal switches, the thermal conductivity of the switch substrate is poor, the heat dissipation capacity of the upper layer is low, and the components need to be made through fine processing, which makes the production difficulty and cost too high. Summary of the invention

[0004] The present invention provides an electrostatically driven thermal switch to solve the technical problem raised in the background technology.

[0005] The present invention provides an electrostatically driven thermal switch, which comprises a thermal switch upper pole, a thermal switch lower pole and a support body arranged between the thermal switch upper pole and the thermal switch lower pole; the thermal switch lower pole comprises a bottom substrate, a conductive lower electrode arranged on the bottom substrate and a lower electrode plate with one side attached to the conductive lower electrode and the other side connected to the support body; the thermal switch upper pole comprises an upper electrode plate connected to one end of the support body away from the lower electrode plate, a conductive upper electrode connected to the upper electrode plate and a color-changing ink layer arranged on the conductive upper electrode; the bottom substrate, the conductive lower electrode and the lower electrode plate are all provided with heat conducting parts inside.

[0006] Furthermore, the upper electrode plate includes a connecting portion connected to the support body, a bending portion connected to the connecting portion, and a contact portion connected to the bending portion for contacting and conducting heat with the lower electrode plate.

[0007] Furthermore, the upper electrode plate is made of polydimethylsiloxane or PVDF material; the lower electrode plate is made of any one of capron tape, polyethylene, polyvinyl chloride, and alumina.

[0008] Furthermore, the heat conducting part is made of graphene composite material.

[0009] Furthermore, a gold coating is provided on a surface of the upper electrode plate that abuts against the lower electrode of the thermal switch.

[0010] Furthermore, a first acrylic pressure-sensitive adhesive layer is provided on a surface of the upper electrode plate away from the lower electrode of the thermal switch, and the conductive upper electrode is connected to the upper electrode plate through the first acrylic pressure-sensitive adhesive layer.

[0011] Furthermore, a second acrylic pressure-sensitive adhesive layer is provided on a surface of the conductive lower electrode away from the bottom substrate; and the lower electrode plate is connected to the conductive lower electrode via the second acrylic pressure-sensitive adhesive layer.

[0012] Furthermore, the conductive upper electrode and the conductive lower electrode are both made of copper foil.

[0013] Furthermore, the bottom substrate is made of silicone or epoxy resin.

[0014] Furthermore, the support body is made of acrylic acid.

[0015] By adopting the above technical scheme, the present invention has at least the following beneficial effects: the present invention embeds heat-conducting parts on the bottom substrate, the conductive lower electrode and the lower electrode plate. When it is necessary to conduct heat to the device connected to the present invention, the heat-conducting part can efficiently transfer the heat of the device to the upper pole of the thermal switch, exchange heat with the ambient space in a radiation manner, and achieve the effect of heat dissipation. In addition, a color-changing ink layer is provided on the conductive upper electrode to enhance the radiation heat transfer capability of the upper pole of the thermal switch and improve the heat dissipation capability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A three-dimensional diagram of the electrostatically driven thermal switch of the present invention.

[0017] Figure 2 It is a partial cross-sectional view of the bottom substrate, the conductive lower electrode, the lower electrode plate and the heat-conducting part of the electrostatically driven thermal switch of the present invention.

[0018] Figure 3 A three-dimensional diagram of the upper electrode plate of the electrostatically driven thermal switch of the present invention. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below by specific implementation methods in conjunction with the accompanying drawings. It should be understood that the embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but cannot be understood as limiting the present invention. Moreover, in the absence of conflict, the features in the embodiments of the present invention can be combined with each other.

[0020] like Figure 1 - 3, the present invention provides an electrostatically driven thermal switch, the electrostatically driven thermal switch comprises a thermal switch upper pole, a thermal switch lower pole and a support body 8 arranged between the thermal switch upper pole and the thermal switch lower pole; the thermal switch lower pole comprises a bottom substrate 1, a conductive lower electrode 2 arranged on the bottom substrate 1 and a lower electrode plate 3 with one side attached to the conductive lower electrode 2 and the other side connected to the support body 8; the thermal switch upper pole comprises an upper electrode plate 5 connected to one end of the support body 8 away from the lower electrode plate 3, a conductive upper electrode 6 connected to the upper electrode plate 5 and a color-changing ink layer 7 arranged on the conductive upper electrode 6; the bottom substrate 1, the A heat conducting part 4 is provided inside the conductive lower electrode 2 and the lower electrode plate 3; thereby, the in-plane thermal conductivity of the heat conducting part 4 is converted into the inter-plane thermal conductivity of the heat conducting part 4 in the underlying substrate 1, the conductive lower electrode 2 and the lower electrode plate 3, so that the heat conducting part 4 can directly conduct the heat of the device. By arranging the heat conducting part 4 for heat conduction and arranging the lower electrode plate 3 as an electrostatic driving component, heat conduction and electrostatic driving are completed by two components, thereby overcoming the problems of low heat conduction efficiency and high production progress requirements caused by the electrostatic driving component and the heat conducting part 4 being realized by one component in the traditional electrostatically driven thermal switch.

[0021] In this embodiment, by embedding a heat conducting part 4 on the bottom substrate 1, the conductive lower electrode 2 and the lower electrode plate 3, when it is necessary to conduct heat to the device connected to the present invention, the heat conducting part 4 can efficiently transfer the heat of the device to the upper electrode of the thermal switch, exchange heat with the ambient space in a radiation manner, and achieve the effect of heat dissipation, and a color-changing ink layer 7 is provided on the conductive upper electrode 6 to enhance the radiation heat transfer ability of the upper electrode of the thermal switch and improve the heat dissipation ability; when working, the upper electrode of the thermal switch and the lower electrode of the thermal switch are respectively connected to the positive and negative electrodes of the DC power supply. When it is necessary to lock the temperature of the device, the power switch is turned off, the circuit is disconnected, and the upper pole of the thermal switch and the lower pole of the thermal switch are separated from each other (the preset separation distance is 1 to 5 mm), so that there is no contact conduction between the upper pole of the thermal switch and the lower pole of the thermal switch, thereby playing the role of locking the temperature; when it is necessary to dissipate heat for the device, the power switch is closed, and under the action of electrostatic force, the upper electrode plate 5 drives the conductive upper electrode 6 and the color-changing ink layer 7 to press down, gradually approaching the lower electrode plate 3 until they fit together so that the thermal switch is in a closed state. The heat conducted up by the heat conducting part 4 is transferred to the upper pole of the thermal switch in a heat conduction manner, and the upper pole of the thermal switch exchanges heat with the ambient space in a radiation manner, thereby realizing heat dissipation for the device; when the heat dissipation effect needs to be disconnected, the power switch is turned off, the upper electrode plate 5 loses the support of the electric field force, the upper electrode plate 5 is separated from the lower electrode plate 3, and returns to a straight state, and the thermal switch completes a working cycle. In this embodiment, color-changing ink is used to enhance the thermal radiation capacity of the upper pole of the thermal switch. Specifically, the color-changing ink is transparent below 40°C, and the thermal emissivity is low, which is 0.8. Above 40°C, the color-changing ink turns black, and the emissivity is high, which is 0.9. When the device needs to dissipate heat, the upper plate 5 is directly in contact with the heat conducting part 4, so that the temperature of the color-changing ink is higher than the color-changing temperature, and the color-changing ink is black, and the emissivity is 0.9, which plays a role in strengthening radiation heat exchange, thereby increasing the heat dissipation when the thermal switch is on, and then improving the switch ratio.

[0022] In a specific embodiment, the upper electrode 5 includes a connecting portion 51 connected to the support body 8, a bending portion 52 connected to the connecting portion 51, and a contact portion 53 connected to the bending portion 52 for contacting and conducting heat with the lower electrode 3; in this embodiment, the contact portion 53 of the upper electrode 5 and the lower electrode 3 for contacting and conducting heat is connected to the connecting portion 51 through the bending portion 52, so that after the present invention completes the heat dissipation work of the device, the power supply is disconnected, and under the action of the restoring force of the bending portion 52, the contact portion 53 can be driven to separate from the lower electrode 3, thereby releasing the heat dissipation work of the device.

[0023] In a specific embodiment, the upper electrode plate 5 is made of polydimethylsiloxane or PVDF material; the lower electrode plate 3 is made of any one of KEPTON, polyethylene, polyvinyl chloride, and aluminum oxide; by utilizing the excellent electrodeformability of the polydimethylsiloxane (PDMS) and the PVDF (polyvinylidene fluoride), the upper electrode plate 5 can be in contact with the lower electrode plate 3 under the action of the electric field force, and when the electric field force is lost, the upper electrode plate 5 can be separated from the lower electrode plate 3; the lower electrode plate 3 uses KEPTON (polyimide), polyethylene, polyvinyl chloride, and aluminum oxide as dielectrics, so as to achieve conduction with the upper electrode of the thermal switch and form an electric field force.

[0024] In a specific embodiment, the heat conducting part 4 is made of a graphene composite material; the graphene composite material is arranged as the heat conducting part 4 inside the bottom substrate 1, the conductive lower electrode 2 and the lower electrode plate 3, so that the in-plane thermal conductivity of the graphene is converted into the inter-plane thermal conductivity between the bottom substrate 1, the conductive lower electrode 2 and the lower electrode plate 3, so that the inter-plane thermal conductivity of the lower electrode of the thermal switch reaches 816.9±12.8 W / m·K, which is much higher than the common high thermal conductivity metals silver and copper; it is embedded in the bottom substrate 1, the conductive lower electrode 2 and the lower electrode plate 3, and plays the role of quickly transferring heat, so that when the power is on, the device is quickly cooled through the upper electrode of the thermal switch.

[0025] In a specific embodiment, a gold coating is provided on one side of the upper electrode plate 5 that abuts against the lower electrode of the thermal switch; when the device needs to lock the temperature, the power switch is turned off, the circuit is disconnected, the upper electrode of the thermal switch and the lower electrode of the thermal switch are separated, and the heat conducted up through the lower electrode of the thermal switch can only be radiated and exchanged with the heat sink; since the lower surface of the upper electrode plate 5 is sprayed with a gold coating, utilizing the characteristic that the thermal emissivity of the gold coating is 0.01, the net heat exchange amount between the lower electrode of the thermal switch and the upper electrode of the thermal switch is small after multiple reflections, and the comprehensive thermal resistance is large, thereby effectively preventing heat loss and playing a role in locking the temperature.

[0026] In a specific embodiment, a first acrylic pressure-sensitive adhesive layer is provided on a surface of the upper electrode plate 5 away from the lower electrode of the thermal switch, and the conductive upper electrode 6 is connected to the upper electrode plate 5 through the first acrylic pressure-sensitive adhesive layer; the good conductivity and viscosity of the acrylic pressure-sensitive adhesive are utilized to realize the connection between the conductive upper electrode 6 and the upper electrode plate 5, so that the upper electrode of the thermal switch can form an electric field force with the lower electrode of the thermal switch when power is turned on, and can also extract heat to play a heat dissipation role.

[0027] In a specific embodiment, a second acrylic pressure-sensitive adhesive layer is provided on a surface of the conductive lower electrode 2 away from the underlying substrate 1; the lower electrode plate 3 is connected to the conductive lower electrode 2 through the second acrylic pressure-sensitive adhesive layer; the conductive lower electrode 2 is connected to the lower electrode plate 3 by utilizing the good conductivity and viscosity of the acrylic pressure-sensitive adhesive, so that the upper electrode of the thermal switch can form an electric field force with the lower electrode of the thermal switch when power is turned on.

[0028] In an optional embodiment, the conductive upper electrode 6 and the conductive lower electrode 2 are both made of copper foil; it should be emphasized that the conductive upper electrode 6 and the conductive lower electrode 2 can also be replaced by other materials as long as they can form an electric field force when powered on.

[0029] In an optional embodiment, the bottom substrate 1 is made of silicone or epoxy resin; it should be emphasized that the bottom substrate 1 can also be replaced by other curing materials with certain adhesiveness.

[0030] In an optional embodiment, the support body 8 is made of acrylic. By utilizing the low thermal conductivity of acrylic, when the upper pole of the thermal switch and the lower pole of the thermal switch are in a separated state, the lower pole of the thermal switch can be prevented from conducting the heat of the device through the support body 8 to the upper pole of the thermal switch, thereby affecting the temperature locking effect on the device. It should be emphasized that the support body 8 can also be replaced by other adhesive materials with low thermal conductivity.

[0031] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that numerous changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An electrostatically driven thermal switch, characterized in that: The electrostatically driven thermal switch comprises a thermal switch upper pole, a thermal switch lower pole and a support body arranged between the thermal switch upper pole and the thermal switch lower pole; The lower pole of the thermal switch includes a bottom substrate, a conductive lower electrode arranged on the bottom substrate, and a lower electrode plate with one side attached to the conductive lower electrode and the other side connected to the support body; the upper pole of the thermal switch includes an upper electrode plate connected to one end of the support body away from the lower electrode plate, a conductive upper electrode connected to the upper electrode plate, and a color-changing ink layer arranged on the conductive upper electrode; the bottom substrate, the conductive lower electrode, and the lower electrode plate are all provided with heat-conducting parts inside.

2. The electrostatically driven thermal switch according to claim 1, characterized in that: The upper electrode plate comprises a connecting portion connected to the support body, a bending portion connected to the connecting portion, and a contact portion connected to the bending portion for contacting and conducting heat with the lower electrode plate.

3. The electrostatically driven thermal switch according to claim 1, characterized in that: The upper electrode plate is made of polydimethylsiloxane or PVDF material; the lower electrode plate is made of any one of capron tape, polyethylene, polyvinyl chloride, and aluminum oxide.

4. The electrostatically driven thermal switch according to claim 1, characterized in that: The heat conducting part is made of graphene composite material.

5. The electrostatically driven thermal switch according to claim 1, characterized in that: A gold coating is provided on a surface of the upper electrode plate abutting against the lower electrode of the thermal switch.

6. The electrostatically driven thermal switch according to claim 1, characterized in that: A first acrylic pressure-sensitive adhesive layer is provided on a surface of the upper electrode plate away from the lower electrode of the thermal switch, and the conductive upper electrode is connected to the upper electrode plate through the first acrylic pressure-sensitive adhesive layer.

7. The electrostatically driven thermal switch according to claim 1, characterized in that: A second acrylic pressure-sensitive adhesive layer is provided on the side of the conductive lower electrode away from the bottom substrate; the lower electrode plate is connected to the conductive lower electrode through the second acrylic pressure-sensitive adhesive layer.

8. The electrostatically driven thermal switch according to claim 1, characterized in that: The conductive upper electrode and the conductive lower electrode are both made of copper foil.

9. The electrostatically driven thermal switch according to claim 1, characterized in that: The bottom substrate is made of silica gel or epoxy resin.

10. The electrostatically driven thermal switch according to claim 1, characterized in that: The support body is made of acrylic acid ester.

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