Thermal management system, methods of forming and operating the same

Abstract

Various embodiments may relate to a thermal management system. The thermal management system may include a dielectrophoresis module configured to be in thermal contact with a heat source. The dielectrophoresis module may include a substrate, a pair of electrodes on the substrate, and an insulator layer over the pair of electrodes. The thermal management system may also include a boiling heat transfer module in thermal contact with the dielectrophoresis module, the boiling heat transfer module including a chamber configured to hold a working fluid. The thermal management system may additionally include a dielectrophoresis modulation controller in electrical connection with the dielectrophoresis module.

Description

THERMAL MANAGEMENT SYSTEM, METHODS OF FORMING AND OPERATING THE SAMECROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority of Singapore application No. 10202400958P filed April 1, 2024, the contents of it being hereby incorporated by reference in its entirety for all purposes.TECHNICAL FIELD

[0002] V arious embodiments of this disclosure may relate to a thermal management system. Various embodiments of this disclosure may relate to a method of forming a thermal management system. Various embodiments of this disclosure may relate to a method of operating a thermal management system.BACKGROUND

[0003] In the past few years, advances in microchip fabrication processes now allow for smaller die sizes at 5-7 nm, a significant shrinkage from the 14-nm node size that was standard up until around 2017. This reduction in die size effectively doubles the node density on a chip, allowing for a substantial increase in processing power and efficiency within the same physical footprint. A direct consequence of the denser node configuration is an elevated heat output from the new-generation chips. As of the early 2020s, this increase in thermal emission has necessitated a parallel evolution in cooling technologies. The demand for advanced, efficient cooling solutions has become a critical aspect of designing and maintaining electrical devices, ensuring that they can operate within safe temperature ranges and maintain performance reliability over time. This need spans across various sectors, including personal computing, data centers, and high-performance computing systems, where optimal temperature management may be required for the longevity and efficiency of devices.

[0004] Several methods are currently employed to cool electrical devices, including forced air convection via heat sink and fan units, water cooling systems, and thermoelectric cooling modules (Peltier units). However, the rapid advancements in chip fabrication technologies havenecessitated cooling solutions with far greater thermal capacities, faster cooling rates, and enhanced thermal stability.

[0005] Forced air cooling stands out as a cost-effective and widely utilized method for managing the temperature of various electrical devices. This approach employs a heat sink block that is placed in direct thermal contact with the heat source. The heat is then dissipated through forced air convection, facilitated by a high-speed fan mounted atop the heat sink. With its simplicity, affordability, and reliability, forced air cooling has been widely used in device temperature management. Its drawbacks, however, include notable noise levels and limited thermal stability. More critically, as the heat output of integrated chips and electrical packages continues to climb, it is projected to soon surpass the cooling capabilities of forced air systems. This impending limitation underscores the necessity of shifting towards alternative cooling methods that can offer higher rates of heat dissipation.

[0006] Water cooling emerges as a superior solution for cooling electrical devices, offering enhanced thermal capacity and a higher rate of heat removal. This method efficiently transfers heat via a circulating liquid block, which is often water- based. Water cooling is predominantly employed in comprehensive systems, including servers, energy systems (such as power supplies), and telecommunications infrastructure. While water cooling surpasses air-based systems in terms of thermal capacity and heat transfer coefficients, its capacity for heat removal and thermal stabilization is increasingly being challenged by the escalating cooling requirements of modern technology.

[0007] Thermoelectric modules, commonly known as Peltier units, offer several advantages over traditional cooling systems. These benefits include affordability, low energy consumption, longevity, compact size, silence, and lightweight design. Despite these strengths, Peltier units exhibit a lower thermal capacity and significantly reduced cooling efficiency compared to previous methods. A key factor contributing to this limitation is the self-heating (Seebeck) effect, which becomes pronounced under high working loads.

[0008] In addition to the cooling methods previously mentioned, two-phase heat transfer has been recognized as a cutting-edge approach for the cooling of electronic chips. This technique primarily involves the boiling of a surrounding fluid on heated surfaces, utilizing the latent heat of evaporation as the principal mechanism for heat removal. As the surface temperature rises, so docs the rate of heat removal through boiling heat transfer, until it reaches a maximum threshold known as the critical heat flux (CHF). Beyond this point, any furtherincrease in surface temperature leads to the onset of film boiling, where a rapid evaporation rate creates a vapor layer that forms a stable film over the surface, significantly hindering heat dissipation. This transition from CHF to film boiling marks a sudden and involuntary switch from high to low heat flux, putting the system at risk of irreversible transition towards diminished heat removal efficiency and surged surface temperature — a phenomenon often referred to as the bum-out of thermal systems. Such a transition is typically regarded as a failure of the system.

[0009] The occurrence of bum-out significantly constrains the effectiveness of cooling systems utilizing two-phase heat transfer. To mitigate this issue, two primary strategies have been developed: the implementation of temperature controllers and the use of thermal liquid circulators. The former involves monitoring the temperature of a heat-dissipating surface and subsequently disconnecting the electrical power if the temperature breaches a predetermined safety threshold. The latter strategy entails the circulation of liquid from temperature-controlled baths over the heat-dissipating surfaces to sustain the desired temperature. Despite these measures, in thermal systems that demand a swift response to both avert overheating and maintain a high heat flux, these approaches often fall short in meeting both criteria simultaneously.SUMMARY

[0010] Various embodiments may relate to a thermal management system. The thermal management system may include a dielectrophoresis module configured to be in thermal contact with a heat source. The dielectrophoresis module may include a substrate, a pair of electrodes on the substrate, and an insulator layer over the pair of electrodes. The thermal management system may also include a boiling heat transfer module in thermal contact with the dielectrophoresis module, the boiling heat transfer module including a chamber configured to hold a working fluid. The thermal management system may additionally include a dielectrophoresis modulation controller in electrical connection with the dielectrophoresis module. The dielectrophoresis modulation controller may be configured to activate the dielectrophoresis module in response to a surface temperature (Tw) of a surface of the dielectrophoresis module being greater than a predefined set temperature (Ts), and equal to or less than a predefined maximum temperature (Tmax). The dielectrophoresis modulation controller may be further configured to deactivate the dielectrophoresis module in response to the surface temperature (Tw) of the surface of the dielectrophoresis module being less than orequal to the predefined set temperature (Ts), and greater than or equal to a predefined minimum temperature

[0011] Various embodiments may provide a method of forming a thermal management system. The method may include providing or forming a dielectrophoresis module configured to be in thermal contact with a heat source. The electrophoresis module may include a substrate, a pair of electrodes on the substrate, and an insulator layer over the pair of electrodes. The method may also include providing or forming a boiling heat transfer module such that the boiling heat transfer module is in thermal contact with the dielectrophoresis module, the boiling heat transfer module including a chamber configured to hold a working fluid. The method may additionally include electrically connecting a dielectrophoresis modulation controller with the dielectrophoresis module. The dielectrophoresis modulation controller may be configured to activate the dielectrophoresis module in response to a surface temperature (Tw) of a surface of the dielectrophoresis module being greater than a predefined set temperature (Ts), and equal to or less than a predefined maximum temperature (Tmax). The dielectrophoresis modulation controller may be further configured to deactivate the dielectrophoresis module in response to the surface temperature (Tw) of the surface of the dielectrophoresis module being less than or equal to the predefined set temperature (Ts), and greater than or equal to a predefined minimum temperature CT,,,,,,).

[0012] Various embodiments may relate to operating a thermal management system. The method may include determining a surface temperature (Tw) of a surface of a dielectrophoresis module, the dielectrophoresis module configured to be in thermal contact with a heat source. The dielectrophoresis module may include a substrate, a pair of electrodes on the substrate, and an insulator layer over the pair of electrodes. The method may also include activating the dielectrophoresis module, using a dielectrophoresis modulation controller in electrical connection with the dielectrophoresis module, in response to the surface temperature (Tw) of the surface of the dielectrophoresis module being greater than a predefined set temperature (Ts), and equal to or less than a predefined maximum temperature (Tmax). The method may further include deactivating the dielectrophoresis module, using the dielectrophoresis modulation controller, in response to the surface temperature (Tw) of the surface of the dielectrophoresis module being less than or equal to the predefined set temperature (Ts), and greater than or equal to a predefined minimum temperature (Tmin). The thermal management system may include a boiling heat transfer module in thermal contact with the dielectrophoresismodule, the boiling heat transfer module including a chamber configured to hold a working fluid.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In the drawings, like reference characters generally refer to the same parts throughout the different views. The drawings are not necessarily drawn to scale, emphasis instead generally being placed upon illustrating the principles of various embodiments. In the following description, various embodiments of the invention are described with reference to the following drawings.FIG. 1 shows a general illustration of a thermal management system according to various embodiments.FIG. 2 shows a general illustration of forming a thermal management system according to various embodiments.FIG. 3 shows a general illustration of operating a thermal management system according to various embodiments.FIG. 4A is a schematic illustrating a temperature stabilization and cooling enhancement (TSCE) system according to various embodiments.FIG. 4B shows (above) a schematic of a planar view of the dielectrophoresis module including the substrate with the interdigitated electrode (IDE) patterns as well as a magnified illustration of a portion of the interdigitated electrode (IDE) patterns according to various embodiments; and (below) a schematic of a cross-sectional view of the dielectrophoresis module including the substrate with the interdigitated electrode (IDE) patterns and an insulator layer over the interdigitated electrode (IDE) patterns corresponding to line A-A’ in the top schematic according to various embodiments.FIG. 4C shows an illustration of the dielectrophoresis modulation controller coupled to the dielectrophoresis module according to various embodiments.FIG. 5A is a flow chart providing an illustration of the operation of the temperature stabilization and cooling enhancement (TSCE) system according to various embodiments.FIG. 5B shows a plot of surface temperature Tw(in degrees Celsius or °C) as a function of time t (in seconds or s) demonstrating the stabilization of the surface temperature according to various embodiments.FIG. 5C shows a plot of surface temperature Tw(in degrees Celsius or °C) as a function of time t (in seconds or s) demonstrating cooling enhancement according to various embodiments.DESCRIPTION

[0014] The following detailed description refers to the accompanying drawings that show, by way of illustration, specific details and embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and structural, logical, and electrical changes may be made without departing from the scope of the invention. The various embodiments are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments.

[0015] Features that are described in the context of an embodiment may correspondingly be applicable to the same or similar features in the other embodiments. Features that are described in the context of an embodiment may correspondingly be applicable to the other embodiments, even if not explicitly described in these other embodiments. Furthermore, additions and / or combinations and / or alternatives as described for a feature in the context of an embodiment may correspondingly be applicable to the same or similar feature in the other embodiments.

[0016] In the context of various embodiments, the articles “a”, “an” and “the” as used with regard to a feature or element include a reference to one or more of the features or elements.

[0017] In the context of various embodiments, the term “about” or “approximately” as applied to a numeric value encompasses the exact value and a reasonable variance, e.g., within 10% of the specified value.

[0018] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0019] By “comprising” it is meant including, but not limited to, whatever follows the word “comprising”. Thus, use of the term “comprising” indicates that the listed elements are required or mandatory', but that other elements are optional and may or may not be present.

[0020] By “consisting of’ it is meant including, and limited to, whatever follows the phrase “consisting of’. Thus, the phrase “consisting of’ indicates that the listed elements are required or mandatory, and that no other elements may be present.

[0021] Embodiments described in the context of one of the thermal management systems are analogously valid for the other thermal management systems. Similarly, embodimentsdescribed in the context of a method arc analogously valid for a thermal management system, and vice versa.

[0022] FIG. 1 shows a general illustration of a thermal management system according to various embodiments. The thermal management system may include a dielectrophoresis module 102 configured to be in thermal contact with a heat source. The dielectrophoresis module 102 may include a substrate, a pair of electrodes on the substrate, and an insulator layer over the pair of electrodes. The thermal management system may also include a boiling heat transfer module 104 in thermal contact with the dielectrophoresis module 102, the boiling heat transfer module 104 including a chamber configured to hold a working fluid. The thermal management system may additionally include a dielectrophoresis modulation controller 106 in electrical connection with the dielectrophoresis module 102. The dielectrophoresis modulation controller 106 may be configured to activate the dielectrophoresis module 102 in response to a surface temperature (Tw) of a surface of the dielectrophoresis module 102 being greater than a predefined set temperature (Ts), and equal to or less than a predefined maximum temperature (Tmax). The dielectrophoresis modulation controller 106 may be further configured to deactivate the dielectrophoresis module 102 in response to the surface temperature (Tw) of the surface of the dielectrophoresis module 102 being less than or equal to the predefined set temperature (Ts), and greater than or equal to a predefined minimum temperature (Tmin).

[0023] In other words, the thermal management system may include a dielectrophoresis module 102, a boiling heat transfer module 104 in thermal connection with the dielectrophoresis module 102, and a dielectrophoresis modulation controller 106 in electrical connection with the dielectrophoresis module 102. The dielectrophoresis module 102 may include a pair of electrodes over a substrate and an insulator layer covering the pair of electrodes, while the boiling heat transfer module 104 may include a chamber for holding a working fluid. When a surface temperature (Tw) of a heated surface of the dielectrophoresis module 102 is greater than a predefined set temperature (Ts) while equal to or less than a predefined maximum temperature (Tmax), the dielectrophoresis modulation controller 106 may turn on the dielectrophoresis module 102 such the dielectrophoretic effect generated by the dielectrophoresis module 102 draws a greater amount of working fluid to the heated surface to increase a transfer rate of heat away from the heated surface, thereby reducing the surface temperature. On the other hand, when the surface temperature (Tw) of the heat surface of the dielectrophoresis module 102 is less than or equal to the predefined set temperature (Ts) whilegreater than or equal to a predefined minimum temperature (Train), the dielectrophoresis modulation controller 106 may turn off the dielectrophoresis module 102 to reduce the transfer rate of heat away from the heated surface.

[0024] For avoidance of doubt, FIG. 1 is intended to illustrate some features of a thermal management system according to various embodiments, and is not intended to limit, e.g., the size, shape, orientation, arrangement etc. of the various features.

[0025] Dielectrophoretic effect may refer to the translation / movement of molecules of the dielectric fluid in response to a non-uniform electric field generated by the pair of electrodes. The dielectric fluid may be or include any dielectric liquid, for instance, Novec HFE-7000, Novec HFE-7100 or Fluorinert FC-72. During operation, the molecules of the dielectric liquid in the chamber near the heated surface may be heated up and be vaporized, before being condensed back when the vapour reaches the cooler part of the chamber to form the dielectric liquid. The heating up, vaporization and subsequent cooling may form a continuous cycle.

[0026] Various embodiments may avert overheating and also maintain a high heat flux.

[0027] In various embodiments, the dielectrophoresis module may also be configured to provide an indication to deactivate the heat source in response to the surface temperature (Tw) being greater than the predefined set temperature (Ts), and greater than the predefined maximum temperature (Tniax). The indication may, for instance, be a display warning or alarm.

[0028] In various embodiments, the dielectrophoresis module may also be configured to provide an indication that the surface temperature is low in response to the surface temperature (Tw) of the surface of the dielectrophoresis module being less than or equal to the predefined set temperature (Ts), and less than the predefined minimum temperature (Tmin). The indication may, for instance, be a display warning or alarm. The indication that the surface temperature is low (i.e., lower than Tsand Tmin) may be different from the indication to deactivate the heat source (i.e., when surface temperature is greater than Tsand Tmax).

[0029] In various embodiments, the dielectrophoresis modulation controller 106 may include a controller and a relay in electrical connection to the controller. The relay may be configured to provide an alternating current (AC) voltage or a direct current (DC) voltage to the dielectrophoresis module for activating or deactivating the dielectrophoresis module 102 in response to a control signal generated by the controller based on the surface temperature (Tw) of the surface of the dielectrophoresis module 102. The relay and the dielectrophoresis module may be configured to be coupled to a voltage supply.

[0030] In various embodiments, the pair of electrodes may include interdigitated electrodes. Each electrode of the pair of electrodes may include an electrode bar and a plurality of fingers extending out from the electrode bar. The plurality of fingers may extend in parallel to one another.

[0031] The pair of electrodes may include any suitable electrically conductive material or materials, including for instance, metals, alloys and / or conductive polymers. In various embodiments, the pah' of electrodes may include indium tin oxide (ITO), copper, gold or chromium.

[0032] In various embodiments, the thermal management system may include a temperature sensor configured to determine the surface temperature (Tw) of the surface of the dielectrophoresis module.

[0033] The insulator layer may include any suitable insulating material which is able to provide adequate insulation at an appropriate thickness of the layer. In various embodiments, the insulator layer may include silicon nitride, SU-8 or Teflon. In various other embodiments, the insulator layer may include a ceramic or ceramics.

[0034] In various embodiments, the boiling heat transfer module may include a heat sink. The heat sink may include any suitable thermally conductive material, c.g., a metal such as copper or aluminum.

[0035] In various embodiments, the boiling heat transfer module may include a forced convection module configured to induce forced convection of the working fluid. The forced convection module may include, for instance, a fan or a pump.

[0036] FIG. 2 shows a general illustration of forming a thermal management system according to various embodiments. The method may include, in 202, providing or forming a dielectrophoresis module configured to be in thermal contact with a heat source. The electrophoresis module may include a substrate, a pair of electrodes on the substrate, and an insulator layer over the pair of electrodes. The method may also include, in 204, providing or forming a boiling heat transfer module such that the boiling heat transfer module is in thermal contact with the dielectrophoresis module, the boiling heat transfer module including a chamber configured to hold a working fluid. The method may additionally include, in 206, electrically connecting a dielectrophoresis modulation controller with the dielectrophoresis module. The dielectrophoresis modulation controller may be configured to activate the dielectrophoresis module in response to a surface temperature (Tw) of a surface of thedielectrophoresis module being greater than a predefined set temperature (Ts), and equal to or less than a predefined maximum temperature (Tmax). The dielectrophoresis modulation controller may be further configured to deactivate the dielectrophoresis module in response to the surface temperature (Tw) of the surface of the dielectrophoresis module being less than or equal to the predefined set temperature (Ts), and greater than or equal to a predefined minimum temperature (Turin).

[0037] In other words, the method may include forming a thermal management system including a dielectrophoresis module, a boiling heat transfer module and a dielectrophoresis modulation controller.

[0038] For avoidance of doubt, FIG. 2 is intended to illustrate steps of a method of forming a thermal management system according to various embodiments, and is not intended to limit the sequence of the various steps. For instance, step 202 may occur before, after or at the same time as step 204.

[0039] In various embodiments, the dielectrophoresis module may also be configured to provide an indication to deactivate the heat source in response to the surface temperature (Tw) being greater than the predefined set temperature (Ts), and greater than the predefined maximum temperature (T max)-

[0040] In various embodiments, the dielectrophoresis module may also be configured to provide an indication that the surface temperature is low in response to the surface temperature (Tw) of the surface of the dielectrophoresis module being less than or equal to the predefined set temperature (Ts), and less than the predefined minimum temperature (Turin).

[0041] In various embodiments, the dielectrophoresis modulation controller may include a controller, and a relay in electrical connection to the controller. The relay may be configured to provide an alternating current (AC) voltage or a direct current (DC) voltage to the dielectrophoresis module for activating or deactivating the dielectrophoresis module in response to a control signal generated by the controller based on the surface temperature (Tw) of the surface of the dielectrophoresis module.

[0042] In various embodiments, the relay and the dielectrophoresis module may be configured to be coupled to a voltage supply.

[0043] In various embodiments, the pair of electrodes may be interdigitated electrodes. The pair of electrodes may include indium tin oxide (ITO), copper, gold or chromium.

[0044] In various embodiments, the method may include providing a temperature sensor configured to determine the surface temperature (Tw) of the surface of the dielectrophoresis module.

[0045] In various embodiments, the insulator layer may include silicon nitride, SU-8 or Teflon. In various other embodiments, the insulator layer may include a ceramic or ceramics.

[0046] In various embodiments, the working fluid may be a dielectric liquid.

[0047] In various embodiments, the boiling heat transfer module may include a heat sink.

[0048] In various embodiments, the boiling heat transfer module may include a forced convection module configured to induce forced convection of the working fluid.

[0049] FIG. 3 shows a general illustration of operating a thermal management system according to various embodiments. The method may include, in 302, determining a surface temperature (Tw) of a surface of a dielectrophoresis module, the dielectrophoresis module configured to be in thermal contact with a heat source. The dielectrophoresis module may include a substrate, a pair of electrodes on the substrate, and an insulator layer over the pair of electrodes. The method may also include, in 304, activating the dielectrophoresis module, using a dielectrophoresis modulation controller in electrical connection with the dielectrophoresis module, in response to the surface temperature (Tw) of the surface of the dielectrophoresis module being greater than a predefined set temperature (Ts), and equal to or less than a predefined maximum temperature (Tmax). The method may further include, in 306, deactivating the dielectrophoresis module, using the dielectrophoresis modulation controller, in response to the surface temperature (Tw) of the surface of the dielectrophoresis module being less than or equal to the predefined set temperature (Ts), and greater than or equal to a predefined minimum temperature (Tniiu). The thermal management system may include a boiling heat transfer module in thermal contact with the dielectrophoresis module, the boiling heat transfer module including a chamber configured to hold a working fluid.

[0050] In other words, various embodiments may relate to determining (e.g., sensing or detecting) a surface temperature (Tw) of a surface of a dielectrophoresis module, followed by activating or deactivating the dielectrophoresis module based on the surface temperature determined.

[0051] For avoidance of doubt, FIG. 3 is not intended to be in sequence. For instance, as mentioned above, step 304 may occur before or after step 306, based on the surface temperature that is determined.

[0052] V arious embodiments may combine boiling heat transfer principles for efficient heat dissipation, and the dielectrophoretic effect for rapid, precise temperature stabilization of heated surfaces. These two effects may be seamlessly integrated, laying the foundation for a thermal management system, i.e., a temperature stabilization and cooling enhancement (TSCE) system. Various embodiments may hold immense potential to revolutionize thermal management with its high performance and on-demand capabilities, promising advanced, fastresponding thermal solutions.

[0053] Various embodiments may be designed to cool down a heat source and stabilize its temperature. The system may include a boiling heat transfer module. The boiling heat transfer module may include a chamber, i.e., a boiling chamber. The boiling chamber may house a working liquid and may position a substrate requiring cooling in contact with the working liquid on one side. The opposite side of the substrate may be thermally connected to a heat source. Cooling the surface of the substrate that is in contact with the liquid may effectively enable heat removal from the heat source. As the heat from the heat source raises the temperature of the surface above the boiling point of the working liquid, boiling of the working liquid may commence. This process may leverage the latent heat of evaporation of the liquid to efficiently draw heat away from the heat source.

[0054] The working liquid may be a dielectric liquid, particularly for cooling electronic equipment. When selecting a working liquid for the TSCE system, three key physical properties may be considered. First, the working liquid may be required to be electrically non-conductive to ensure the safety of electronic devices. Second, to enhance the dielectrophoretic effect, the working liquid may ideally possess a high dipole moment. Finally, the boiling point of the liquid may align with the operational temperature range of the intended cooling application, ensuring optimal performance.

[0055] The boiling heat transfer module may also include a heat sink on one side of the boiling chamber to complete the heat removal process. The heat sink may also condense the vaporized liquid and discharge the surplus heat, facilitating efficient thermal management.

[0056] The boiling heat transfer module or the boiling chamber may also include a forced convection submodule designed to induce forced convection of the working liquid for enhancing heat transfer efficiency.

[0057] The thermal management system may also include a dielectrophoresis module with a heat-dissipating surface incorporating interdigitated electrodes (IDE), which are shieldedfrom the liquid by a thin dielectric layer. It may be required for the electrodes to be alternately arranged to trigger the dielectrophoretic effect in the liquid close to the heated surface upon the application of a voltage. In the demonstrated TSCE system, the substrate may include silicon as the substrate material. An indium tin oxide (ITO) IDE pattern may subsequently be sputtered onto the substrate, followed by the addition of a silicon nitride layer to ensure electrical insulation. The dimensions and spacing between the electrodes may have significant impact on the performance of the TSCE system.

[0058] The TSCE system may also include a dielectrophoresis modulation controller configured to activate a dielectrophoresis module by applying a high voltage (U) to the IDE. The voltage applied to the IDE may be either a direct current (DC) or an alternating current (AC), with AC being the preferred choice due to its inherent safety benefits during operation. The process of turning the voltage supply ON or OFF may be managed through a relay. The relay may be triggered by a dedicated controller based on real-time temperature feedback from the heated surface. The physical mechanisms during the ON and OFF stages are as follows:

[0059] [OFF] Dielectrophoresis deactivated: the heated surface is cooled by the usual two- phase heat transfer mechanism: the rate of heat removal is equal to the latent heat of evaporation of the vaporized liquid next to the heated surface. The surface temperature Twresults from a balance between the heat flux through the surface and the liquid’s evaporation rate.

[0060] [ON] Dielectrophoresis activated: the dielectrophoretic effect draws more liquids to the heated surface to vaporize. Effectively, this increases the heat transfer rate and reduces the surface temperature.

[0061] A TSCE system is demonstrated to cool a surface heated by a heat source, with a constant heat generation rate (<?) maintained throughout the demonstration. This TSCE system may specifically be engineered to achieve two key objectives: (1) to maximize the rate of heat removal from the surface, and (2) to rapidly respond by activating the dielectrophoretic effect, ensuring the surface temperature stabilizes close to the predefined set temperature (Ts).

[0062] During operation of the demonstrating TSCE system, the surface temperature Twmay be required to be in the range Tmin < Tw< Tmax, where Tmin and Tmax respectively are the user-defined lower and upper bounds of the operating temperature range:

[0063] Safety Assessment: in the case of Tw> Tmax, the heat source generates too much heat for the handling capacity of the cooling system and needs to be shut down for safety.

[0064] Trigger Assessment: In the case of w min the surface is already cooled, and it is unnecessary to trigger the dielectrophoretic effect. The schematic of the TSCE system is illustrated in FIG. 4A.

[0065] FIG. 4A is a schematic illustrating a temperature stabilization and cooling enhancement (TSCE) system according to various embodiments. The system may include a dielectrophoresis module 402 with a heat conductive substrate, IDE patterns on the substrate and a thin dielectric layer electrically shielding the substrate and the IDE patterns, a boiling heat transfer module 404 in thermal contact with the dielectrophoresis module 402 , the boiling heat transfer module 404 being or including a chamber configured to hold a working fluid (and the vapor of the working fluid), and a dielectrophoresis modulation controller 406 in electrical connection with the dielectrophoresis module 402. The dielectrophoresis module 402 may be sandwiched by the boiling heat transfer module 404 and a heat source 408. The heat source 408 may include or be a cartridge heater used to generate a fixed heat flux q through the heat dissipating substrate of the dielectrophoresis module 402. The chamber may be thermally insulated and may contain a dielectric liquid (HFE-7000, 3M). A reflux condenser may be installed on top of the liquid pool to condense evaporated liquid. The system may additionally include a heat sink 410 in thermal contact with the boiling heat transfer module 404. The system may also include an optional submodule 404’ for forced convection.

[0066] The IDE patterns may be connected to a high-voltage power supply and a relay of the dielectrophoresis modulation controller 406. FIG. 4B shows (above) a schematic of a planar view of the dielectrophoresis module 402 including the substrate 412 with the interdigitated electrode (IDE) patterns 414a, 414b as well as a magnified illustration of a portion of the interdigitated electrode (IDE) patterns according to various embodiments; and (below) a schematic of a cross-sectional view of the dielectrophoresis module 402 including the substrate 412 with the interdigitated electrode (IDE) patterns 414a, 414b and an insulator layer 412’ over the interdigitated electrode (IDE) patterns 414a, 414b corresponding to line A-A’ in the top schematic according to various embodiments. One of the IDE patterns 414a may be biased to a positive voltage, while another of the IDE patterns 414b may be biased to a negative voltage. FIG. 4C shows an illustration of the dielectrophoresis modulation controller 406 coupled to the dielectrophoresis module 402 according to various embodiments. The dielectrophoresis modulation controller 406 may include a controller 416 and an AC / DC relay 418 connected to the controller 416. The AC / DC relay 418 may be connected to the dielectrophoresis module402. The controller 416 may switch the AC / DC relay 418 ON if Tw> Ts(electrophoresis activation), and OFF if Tw< Ts(electrophoresis deactivation). An AC / DC voltage supply 420 may be connected or coupled to the AC / DC relay 418 and the dielectrophoresis module 402. Twmay be sensed or detected by a temperature sensor 402’.

[0067] More specifically, the AC / DC voltage supply 420 may be connected to the IDE pattern 414a, while the AC / DC relay 418 may be connected to another IDE pattern 414b. The AC / DC relay 418 may be switched ON or OFF based on a control signal from the controller 416. When the AC / DC relay 418 is switched ON, the IDE pattern 414b may be electrically connected to the AC / DC voltage supply 420 via the AC / DC relay 418, thereby allowing electrophoresis. Conversely, when the AC / DC relay 418 is switched OFF, the IDE pattern 414b may be electrically disconnected from the AC / DC voltage supply 420, leading to deactivation of electrophoresis.

[0068] For avoidance of doubt, in various embodiments, the dimensions, arrangements and shapes etc. of the various components of the TSCE system may depart from those shown in FIGS. 4A - C.

[0069] FIG. 5A is a flow chart providing an illustration of the operation of the temperature stabilization and cooling enhancement (TSCE) system according to various embodiments. The operation may include the following steps:

[0070] Initialization:

[0071] (i) A fixed heat flux q is generated by the heat source.

[0072] (ii) Input parameters:

[0073] Temperature limits Tmin and Tmax to define the range of operational temperature.

[0074] Target temperature Ts.

[0075] Safety & Trigger assessment:

[0076] The system takes surface temperature feedback Twand compares it with Tmin and Tmax:

[0077] Output 1: Tw> Tmax, the heat source generates too much heat for the handling capacity of the cooling system. The system needs to be shut down for safety.

[0078] Output 2: Tw< Tmin, the surface is low and docs not require triggering of the dielectrophoretic effect.

[0079] Electrophoresis modulation:

[0080] The surface temperature is determined within the operational range (Tmin < Tw< Tmax):

[0081] Output 3: The system alternatively activates the diclcctrophorctic effect if Tw< Tsand deactivates it if Tw> Ts. The surface temperature stabilizes towards Ts.

[0082] FIG. 5B shows a plot of surface temperature Tw(in degrees Celsius or °C) as a function of time t (in seconds or s) demonstrating the stabilization of the surface temperature according to various embodiments. The plot shows changes in surface temperature with time when the supplied voltage is 900 V.

[0083] Initially, with the dielectrophoretic effect being OFF (indicated by the shaded region), the temperature Twrises due to a fixed heat flux q. In the initial absence of the dielectrophoretic effect (as indicated by the shaded area), Twspikes until it surpasses Ts.

[0084] Should Twexceed Tsand the dielectrophoretic effect remains OFF, the temperature rapidly escalates (as shown by the dotted line). Conversely, activating the dielectrophoretic effect, in accordance with the control scheme shown in FIG. 5A, results in the surface temperature swiftly stabilizing at Ts. Solid line arrows indicate when the diclcctrophorctic effect is activated (that is, when Tw> Ts), while dashed line arrows show the deactivation points of the diclcctrophorctic effect (that is, when Tw< Ts). The dashed line represents the target temperature Ts.

[0085] With dielectrophoretic modulation, the deviation of Twfrom T, decreases and stays within 0.1 K (i.e., ±0.1 K ) after 10 seconds. After 200 s, an ultra-small temperature variation of ±0.025 K is achieved.

[0086] FIG. 5C shows a plot of surface temperature Tw(in degrees Celsius or °C) as a function of time t (in seconds or s) demonstrating cooling enhancement according to various embodiments. Cooling enhancement is demonstrated by intensifying the dielectrophoretic effect by increasing the voltage U. For the same heat flux, the system is able to cool the surface temperature to lower targets — specifically, from 104 °C, to 92 °C, and further to 81 °C, by adjusting the voltage U to 600 V, 900 V, and 1200 V, respectively.

[0087] The abovementioned may indicate the feasibility of a temperature stabilization and cooling enhancement (TSCE) system that allows not only high-capacity heat dissipation from a heated surface using two-phase cooling, but also rapid, precise, and on-demand control of surface temperature using several control parameters, including the applied voltage, themodulating frequency, and / or the electrode pattern. This may allow greater flexibility in designing and optimizing performance of the TSCE system towards practical applications.

[0088] Various embodiments may achieve the following using two-phase heat transfer and dielectrophoretic effect.

[0089] Rapid Temperature Stabilization. Various embodiments may achieve fast temperature stabilization, essential for applications that need an immediate reaction to thermal fluctuations. It may merge the effective heat removal of two-phase heat transfer with the precise control provided by the dielectrophoretic effect, enabling it to swiftly counteract temperature variations. As a result, cooling systems can rapidly attain and consistently maintain the targeted temperature.

[0090] Cooling Enhancement. Various embodiments may utilize two-phase heat transfer for enhanced cooling performance while effectively preventing burn-out caused by excessive vapor generation. Additionally, it may employ the dielectrophoretic effect to direct coolant flow towaids the heated surface, enabling a higher heat transfer rate than typical two-phase heat transfer methods offer.

[0091] Improved Temperature Stability and Reduced Risk of Overheating. Various embodiments may improve temperature stability and reduce temperature variations that can cause thermal stress and fatigue on materials. This stability may be vital for prolonging the life of electronic devices, as fluctuations in temperature and overheating are primary reasons for their failure. By actively maintaining component operation within safe thermal boundaries, it may significantly lower the risk of overheating and related failures.

[0092] Scalability. Various embodiments may be applied at any scale, from micro-scale electronic components to large industrial systems. The performance of various embodiments may remain consistent regardless of size, making it perfect for a variety of thermal management needs. As electronic devices shrink and increase their power density, or as industrial operations demand greater cooling power, this scalable technology according to various embodiments may be able to adjust to meet these changing requirements.

[0093] This temperature-stabilization and cooling enhancement (TSCE) device may hold significant promise in thermal management, rapid dynamic cooling, and the microprocessor manufacturing industry. Various embodiments may relate to an innovative and modular design showcasing the capacity to leverage, integrate, and enhance the capabilities of (1) the fast and effective action of the dielectrophoretic effect, and (2) the highly efficient two-phase heattransfer. This synergy may pave the way for a new generation of quick, adaptable, and precise TSCE devices. Remarkably, the TSCE device can simultaneously achieve three optimization targets - minimalization of stabilization time, enhanced accuracy, and maximization of heat transfer capacity - a level of performance not commonly found in existing temperature control devices.[0094J The development of this technology may have considerable commercial appeal for thermal management systems, particularly in cooling and temperature stabilization of electronic devices. Various embodiments may provide flexibility in managing the desired surface temperature and heat transfer rate to suit various cooling needs and user preferences.

Claims

Claims1. A thermal management system comprising: a dielectrophoresis module configured to be in thermal contact with a heat source, the dielectrophoresis module comprising: a substrate; a pair of electrodes on the substrate; and an insulator layer over the pair of electrodes; a boiling heat transfer module in thermal contact with the dielectrophoresis module, the boiling heat transfer module comprising a chamber configured to hold a working fluid; and a dielectrophoresis modulation controller in electrical connection with the dielectrophoresis module; wherein the dielectrophoresis modulation controller is configured to activate the dielectrophoresis module in response to a surface temperature (Tw) of a surface of the dielectrophoresis module being greater than a predefined set temperature (Ts), and equal to or less than a predefined maximum temperature (Tmax); and wherein the dielectrophoresis modulation controller is further configured to deactivate the dielectrophoresis module in response to the surface temperature (Tw) of the surface of the dielectrophoresis module being less than or equal to the predefined set temperature (Ts), and greater than or equal to a predefined minimum temperature (Twin).

2. The thermal management system according to claim 1, wherein the dielectrophoresis module is also configured to provide an indication to deactivate the heat source in response to the surface temperature (Tw) being greater than the predefined set temperature (Ts), and greater than the predefined maximum temperature (Tmax).

3. The thermal management system according to claim 1 or claim 2, wherein the dielectrophoresis module is also configured to provide an indication that the surface temperature is low in response to the surface temperature (Tw) of the surface of the dielectrophoresis module being less than or equal to the predefined set temperature (Ts), and less than the predefined minimum temperature (Twin).

4. The thermal management system according to any one of claims 1 to 3, wherein the dielectrophoresis modulation controller comprises: a controller; and a relay in electrical connection to the controller; wherein the relay is configured to provide an alternating current (AC) voltage or a direct current (DC) voltage to the dielectrophoresis module for activating or deactivating the dielectrophoresis module in response to a control signal generated by the controller based on the surface temperature (Tw) of the surface of the dielectrophoresis module.

5. The thermal management system according to claim 4. wherein the relay and the dielectrophoresis module are configured to be coupled to a voltage supply.

6. The thermal management system according to any one of claims 1 to 5, wherein the pair of electrodes are interdigitated electrodes.

7. The thermal management system according to any one of claims 1 to 6. wherein the pair of electrodes comprise indium tin oxide (ITO), copper, gold or chromium.

8. The thermal management system according to any one of claims 1 to 7, further comprising: a temperature sensor configured to determine the surface temperature (Tw) of the surface of the dielectrophoresis module.

9. The thermal management system according to any one of claims 1 to 8, wherein the insulator layer comprises silicon nitride, SU-8 or Teflon.

10. The thermal management system according to any one of claims 1 to 9, wherein the working fluid is a dielectric liquid.

11. The thermal management system according to any one of claims 1 to 10, wherein the boiling heat transfer module comprises a heat sink.

12. The thermal management system according to any one of claims 1 to 1 1 , wherein the boiling heat transfer module comprises a forced convection module configured to induce forced convection of the working fluid.

13. A method of forming a thermal management system, the method comprising: forming a dielectrophoresis module configured to be in thermal contact with a heat source, the dielectrophoresis module comprising: a substrate; a pair of electrodes on the substrate; and an insulator layer over the pair of electrodes; providing a boiling heat transfer module such that the boiling heat transfer module is in thermal contact with the dielectrophoresis module, the boiling heat transfer module comprising a chamber configured to hold a working fluid; andelectrically connecting a dielectrophoresis modulation controller with the dielectrophoresis module; wherein the dielectrophoresis modulation controller is configured to activate the dielectrophoresis module in response to a surface temperature (Tw) of a surface of the dielectrophoresis module being greater than a predefined set temperature (Ts), and equal to or less than a predefined maximum temperature (Tmax); and wherein the dielectrophoresis modulation controller is further configured to deactivate the dielectrophoresis module in response to the surface temperature (Tw) of the surface of the dielectrophoresis module being less than or equal to the predefined set temperature (Ts), and greater than or equal to a predefined minimum temperature (Twin).

14. The method according to claim 13, wherein the dielectrophoresis module is also configured to provide an indication to deactivate the heat source in response to the surface temperature (Tw) being greater than the predefined set temperature (Ts), and greater than the predefined maximum temperature (TIIiaA).

15. The method according to claim 13 or claim 14, wherein the dielectrophoresis module is also configured to provide an indication that the surface temperature is low in response to the surface temperature (Tw) of the surface of the dielectrophoresis module being less than or equal to the predefined set temperature (Ts), and less than the predefined minimum temperature (Twin).

16. The method according to any one of claims 13 to 15, wherein the dielectrophoresis modulation controller comprises: a controller; and a relay in electrical connection to the controller;wherein the relay is configured to provide an alternating current (AC) voltage or a direct current (DC) voltage to the dielectrophoresis module for activating or deactivating the dielectrophoresis module in response to a control signal generated by the controller based on the surface temperature (Tw) of the surface of the dielectrophoresis module.

17. The method according to claim 16, wherein the relay and the dielectrophoresis module are configured to be coupled to a voltage supply.

18. The method according to any one of claims 13 to 17, wherein the pair of electrodes are interdigitated electrodes.

19. The method according to any one of claims 13 to 18, wherein the pair of electrodes comprise indium tin oxide (ITO), copper, gold or chromium.

20. The method according to any one of claims 13 to 19, further comprising: providing a temperature sensor configured to determine the surface temperature (Tw) of the surface of the dielectrophoresis module.

21. The method according to any one of claims 13 to 20, wherein the insulator layer comprises silicon nitride, SU-8 or Teflon.

22. The method according to any one of claims 13 to 21, wherein the working fluid is a dielectric liquid.

23. The method according to any one of claims 13 to 22, wherein the boiling heat transfer module comprises a heat sink.

24. The method according to any one of claims 13 to 23, wherein the boiling heat transfer module comprises a forced convection module configured to induce forced convection of the working fluid.

25. A method of operating a thermal management system, the method comprising: determining a surface temperature (Tw) of a surface of a dielectrophoresis module, the dielectrophoresis module configured to be in thermal contact with a heat source, the dielectrophoresis module comprising: a substrate; a pair of electrodes on the substrate; and an insulator layer over the pair of electrodes; activating the dielectrophoresis module, using a dielectrophoresis modulation controller in electrical connection with the dielectrophoresis module, in response to the surface temperature (Tw) of the surface of the dielectrophoresis module being greater than a predefined set temperature (Ts), and equal to or less than a predefined maximum temperature (Tmax); and deactivating the dielectrophoresis module, using the dielectrophoresis modulation controller, in response to the surface temperature (Tw) of the surface of the dielectrophoresis module being less than or equal to the predefined set temperature (Ts), and greater than or equal to a predefined minimum temperature (Twin): wherein the thermal management system also comprises: a boiling heat transfer module in thermal contact with the dielectrophoresis module, the boiling heat transfer module comprising a chamber configured to hold a working fluid.

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