Methods and apparatus for thermal energy management in electric vehicles

Abstract

A method and apparatus for the thermal energy management of systems of electrically powered vehicles (EVs), which enhance the mission capabilities, or performance. The method includes an approach in which thermal energy harvesting, dissipation, storage, and distribution operate in concert. The method concurrently enables, immediate and longer-term management, including storage of thermal energy for subsequent use. The apparatus, includes the multi-functional integration of thermal energy storage, for the benefit of enhanced EV form, capabilities or performances. The apparatus includes connecting elements which provide selective, thermal conduction pathways, which link the management system. The thermal conductive pathways may be actuated in response to temperature, or by other activation means. Thermally managed systems which require persistent heating, or cooling or maintenance within a specified range, are addressed.

Claims

1. A thermal energy management system for an electrically powered vehicle, comprising: a thermal energy harvesting subsystem for absorbing energy that includes non-thermal energy and converting the non-thermal energy to thermal energy; a thermal energy storage medium for storing the thermal energy; a first selectively actuatable thermal energy interconnect, or conduit, for selectively transferring the thermal energy between the thermal energy harvesting subsystem and the thermal energy storage medium; a thermally managed subsystem to be maintained within an operating range of temperatures; and a second selectively actuatable thermal energy interconnect, or conduit, for selectively transferring the thermal energy between the thermal energy storage medium and the thermally managed subsystem, the second selectively actuatable thermal energy conduit being configured so that the thermal energy is selectively transferred between the thermal energy storage medium and the thermally managed subsystem to maintain the thermally managed subsystem within the operating range of temperature; and a thermal energy dissipation subsystem for selectively transferring the thermal energy to an external environment; a third selectively actuatable thermal energy interconnect, or conduit, for selectively transferring the thermal energy between the thermally managed subsystem and the thermal energy storage medium; and a fourth selectively actuatable thermal energy interconnect, or conduit, for selectively transferring the thermal energy between the thermal energy storage medium and the thermal energy dissipation system.

2. The system of claim 1, further comprising a fifth selectively actuatable thermal energy interconnect, or conduit, for selectively transferring the thermal energy between the thermal energy dissipation system and the external environment.

3. The system of claim 1, wherein the thermal energy storage medium includes a battery that stores electrochemical energy in addition to thermal energy.

4. The system of claim 1, in which the thermal energy harvesting subsystem includes a thermo-electric generator for generating electrical energy to be stored in a battery or used to provide energy to other systems of the electrically powered vehicle.

5. The system of claim 1, wherein the thermal energy storage medium includes one or more phase change materials (PCMs).

6. The system of claim 5, wherein the PCMs are dispersed in one or more components of a battery.

7. The system of claim 6, wherein the PCMs are configured to release thermal energy by undergoing a phase change as the battery temperature decreases to a pre-selected lower limit of the operating range of the battery.

8. The system of claim 6, wherein the PCMs are configured to absorb thermal energy by undergoing a phase change as the battery temperature increases to a pre-selected upper limit of the operating range of the battery.

9. The system of claim 6, wherein the thermal storage medium further includes at least a portion of a structural frame of the vehicle.

10. The system of claim 9, further comprising at least one PCM material dispersed within the portion of the structural frame.

11. The system of claim 10, wherein the portion of the structural frame includes a porous, or nanostructured structural material within which the PCM material is dispersed.

12. The system of claim 10, further comprising an insulating material surrounding the thermal storage medium, interconnects or conduits.

13. The system of claim 12, wherein the insulating material includes an aerogel.

14. The system of claim 1, wherein the thermal storage medium includes at least a portion of a structural frame of the electrically powered vehicle.

15. The system of claim 1, wherein the thermal energy harvesting subsystem includes a skin, or a film, extending over a self-supporting surface portion of the electrically vehicle for harvesting and/or dissipating thermal energy.

16. The system of claim 15, wherein the skin or the film includes at least one photovoltaic cell.

17. The system of claim 15, wherein the skin or the film includes an anti-icing (AI) and/or a de-icing (DI) layer.

18. The system of claim 15, wherein the thermal energy harvesting subsystem includes one or more photovoltaic cells located in the film or a skin, as a source of thermal energy.

19. The system of claim 15, wherein the film or the skin is a flexible skin that has a selectively tunable reflectivity.

20. The system of claim 1, wherein the thermally managed subsystems include one or more processors or microprocessors, located on the vehicle.

21. The system of claim 1, wherein the thermal energy harvesting subsystem includes one or more processors, or microprocessors, located on the vehicle, as a source of thermal energy.

22. The system of claim 1, wherein at least one of the first and second interconnects, or conduits, includes conductive material having a tunable, or interruptible, thermal conductivity that is tunable or interruptible by changes in temperature.

23. The system of claim 1, further comprising a first thermally conductive material disposed between the thermal energy harvesting subsystem and the first interconnect, or conduit.

24. The system of claim 23, wherein the thermally conductive material includes a graphene sheet.

25. The system of claim 23, further comprising a second thermally conductive material disposed between the thermal storage medium and the second interconnect, or conduit.

26. The system of claim 1, wherein the second selectively actuatable thermal energy interconnect, or conduit, is configured to selectively transfer thermal energy from the thermal energy storage medium to the thermally managed subsystem and from the thermally managed subsystem to the thermal energy storage medium.

27. A method for managing the thermal energy management system of claim 1 in an electrically powered vehicle, comprising: harvesting non-thermal energy and converting the non-thermal energy to thermal energy; selectively transferring the thermal energy to a thermal energy storage medium; at least one thermally managed subsystem to be maintained within a prescribed range of performance parameters; and selectively transferring the thermal energy between the thermal energy storage medium and the thermally managed subsystem so that the thermally managed subsystem is maintained within the prescribed range of performance parameters.

28. The method of claim 27, wherein the prescribed range of performance parameters includes a prescribed range of temperatures.

29. The method of claim 27, wherein selectively transferring the thermal energy to the thermal energy storage medium includes selectively transferring the thermal energy to and from the thermal energy storage medium to facilitate maintaining the performance parameters within the prescribed range.

30. The method of claim 29, further comprising selectively transferring the thermal energy from the thermal energy storage medium to a thermal energy dissipation system.

31. The method of claim 30, further comprising selectively transferring the thermal energy between the thermal energy dissipation system and an external environment.

32. The method of claim 31, wherein the external environment includes a second electrically powered vehicle.

33. The method of claim 27, wherein the at least one thermally managed subsystem includes a plurality of thermally managed subsystems disposed in or on the electrically powered vehicle.

34. The method of claim 27, further comprising continuously controlling the harvesting and selective transfer of the thermal energy to maintain the performance parameters within the prescribed range.

35. The method of claim 27, wherein the prescribed range of performance parameters includes a range of anticipated performance parameters.

36. The method of claim 27, wherein the anticipated performance parameters include performance parameters that are anticipated in advance of need based on navigation and/or weather information.

37. The method of claim 27, further comprising pre-adjusting the harvesting and selective transfer of the thermal energy to anticipate in advance of need the prescribed range of performance parameters that will be required.

38. The method of claim 37, wherein the pre-adjusting is based on navigation and/or weather information.

39. The method of claim 37, wherein the pre-adjusting is based on a mission plan for the electrically powered vehicle.

40. The method of claim 27, further comprising controlling the harvesting and selective transfer of the thermal energy using external communication connectivity.

41. The method of claim 27, wherein operation and control of the thermally managed subsystem includes multi-level management including distinct long-term mission management, medium-term management and instantaneous management, with medium-term management implemented in response to input from pre-existing communication, or sensory, devices in the electrically powered vehicle.

42. The method of claim 41, wherein the pre-existing systems include geolocational systems, navigation and/or communication systems.

43. The method of claim 27, wherein the thermal storage system includes centralized, partitioned or distributed thermal storage elements that are configured to operate in a coordinated fashion in response to, or anticipation of, specific thermal management requirements.

44. The method of claim 43, wherein the specific thermal management requirements include extreme temperatures and/or diurnal variations.

45. The method of claim 27, wherein the thermal energy storage medium includes one or more phase change materials (PCMs).

46. The method of claim 45, wherein the PCMs are dispersed in one or more components of a battery.

47. The method of claim 46, wherein the PCMs are configured to absorb thermal energy by undergoing a phase change as the battery temperature increases to a pre-selected upper limit of the operating range of the battery.

48. The method of claim 45, wherein the PCMs are configured to release thermal energy by undergoing a phase change as the battery temperature decreases to a pre-selected lower limit of the operating range of the battery.

49. The method of claim 27, wherein the thermal energy storage medium includes a battery that stores electrochemical energy in addition to thermal energy.

50. The method of claim 49, wherein the thermal storage medium further includes at least a portion of a structural frame of the electrically powered vehicle.

51. The method of claim 49, wherein the thermal storage medium further includes at least a portion of a structural frame of the vehicle.

52. The method of claim 51, further comprising at least one PCM material dispersed within the portion of the structural frame.

53. The method of claim 52, wherein the portion of the structural frame includes a porous, or nanostructured structural material within which the PCM material is dispersed.

54. The method of claim 27, wherein harvesting non-thermal energy includes harvesting the non-thermal energy from a thermal energy harvesting subsystem that includes a skin, or a film, extending over a self-supporting surface portion of the electrically powered vehicle for harvesting and/or dissipating thermal energy.

55. The method of claim 54, wherein the skin or the film includes at least one photovoltaic cell.

56. The method of claim 55, wherein the skin or the film includes an anti-icing (AI) and/or a de-icing (DI) layer.

57. The method of claim 54, wherein the thermal energy harvesting subsystem includes one or more processors, or microprocessors, located on the vehicle, as a source of thermal energy.

58. The method of claim 54, wherein the thermal energy harvesting subsystem includes one or more photovoltaic cells located in the film or a skin, as a source of thermal energy.

59. The method of claim 54, wherein the film or the skin is a flexible skin that has a selectively tunable reflectivity.

60. The method of claim 27, wherein the thermally managed subsystems include one or more processors or microprocessors, located on the vehicle.

61. The method of claim 27, wherein the thermal energy is selectively transferred using a conductive material having a tunable, or interruptible, thermal conductivity that is tunable or interruptible by changes in temperature.

62. The method of claim 27 wherein the thermal energy storage medium includes all or part of the structure of the electrically powered vehicle.

63. The method of claim 27 wherein the thermal energy storage medium includes a subsystem of the electrically powered vehicle.

64. The method of claim 27 wherein the thermal energy storage medium includes a component of the electrically powered vehicle.

65. The method of claim 27 wherein the thermal energy storage medium includes a payload of the electrically powered vehicle.

66. The method of claim 65 wherein the thermal energy storage medium includes a sub-system or component of a payload of the electrically powered vehicle.

67. The method of claim 66, wherein the payload or subsystem or component therein are heat-generating and/or heat-dissipating.

68. The method of claim 66, wherein the payload is in thermal communication with the electrically powered vehicle and defines at least a portion of the thermal management system.

69. The method of claim 65, wherein the payload or subsystem or component therein are heat-generating and/or heat-dissipating.

70. The method of claim 69, wherein the payload is in thermal communication with the electrically powered vehicle and defines at least a portion of the thermal management system.

71. The method of claim 65, wherein the payload is in thermal communication with the electrically powered vehicle and defines at least a portion of the thermal management system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 represents one example of the functional elements of a holistic, integrated, thermal management system in an EV.

(2) FIG. 2 represents another example of the functional elements of a thermal management system in an EV, which includes a solar thermal harvesting skin, an integrated thermal storage sub-system, a thermally managed sub-system, or device and thermal interconnection of these systems.

(3) FIG. 3 represents one example of a thermal storage subsystem which is integrated within a structural element of an EV frame and its thermal interconnection.

(4) FIG. 4 represents another example of a thermal storage subsystem, which is integrated within a electrochemical battery of an EV and its thermal interconnection.

(5) FIG. 5 represents an example of a thermal storage medium that comprises a centralized thermal storage element in which single or multiple systems that require thermal management are connected to the centralized thermal storage element.

(6) FIG. 6 represents an example of a thermal storage medium that comprises a series of distributed thermal storage elements that are each in selective thermal connection with different systems which require thermal management.

(7) FIG. 7 is a flowchart showing one example of a process for selectively communicating thermal energy using the techniques described herein between and among a thermal energy harvesting system, a thermal energy storage medium, thermally managed system and thermal energy dissipating system.

DETAILED DESCRIPTION

(8) In one aspect, the current disclosure relates to thermal management systems integrated within the EV structures and/or subsystems to achieve advantages in size, weight, operational power requirements or other benefits for the EV form or capabilities.

(9) There is extensive material available which may be used as resources for implementing various embodiments of the subject matter disclosed herein. For example, many resources are available concerning the thermal properties of materials, structures and system engineering, including, thermal conduction, thermal interfaces, temperature-gradient driven, or pumped, heat flow. PCMs, which are pertinent for thermal energy storage, are well documented, including inorganic, organic and mixed materials, in bulk, or dispersed form, which span an almost unlimited temperature range. There are commercial suppliers, including PureTemp LLC, Plymouth Minn., that provide custom PCMs, for different applications and temperatures.

(10) Other recent advances, in science and technology areas, also have the potential to be pertinent in the implementation of some embodiments of the current invention. Examples include; (i) The incorporation of PCMs in encasements for the local thermal management of Li-batteries (see, for example, J. Kelly, “Passive thermal management of Li-ion batteries using phase change materials, Electronics Protection Magazine, Summer Issue, 8-9, 2014; and W. Q. Li, Z. G. Qu, Y. L. He, Y. B. Tao, “Experimental study of a passive thermal management system for high-powered lithium ion batteries using porous metal foam saturated with phase change materials”, Journal of Power Sources, Volume 255, 9-15, 2014), (ii) assembled monolayer graphene sheets, which are thin and lightweight, with high thermal conductivity for efficient thermal energy transport (see, for example Nan Wang, Majid Kabiri Samani, Hu Li, Lan Dong, Zhongwei Zhang, Peng Su, Shujing Chen, Jie Chen, Shirong Huang, Guangjie Yuan, Xiangfan Xu, Baowen Li, Klaus Leifer, Lilei Ye, Johan Liu, “Tailoring the Thermal and Mechanical Properties of Graphene Film by Structural Engineering”, Small, Vol 14, 2018.), (iii) nanostructured thermal interface materials (TIM) which enable rapid thermal transport across component, or sub-system, interfaces (see, for example Hendricks, Terry J., Chang, Chih-hung, Choi, Changho, Krishnan, Shankar, Paul, Brian “Enhancement of pool boiling heat transfer using nanostructured surfaces on aluminum and copper”, International Journal of Heat and Mass Transfer, Volume 53, 3357-3365, 2010; and Andrew J. McNamara, Yogendra Joshi, Zhuomin M. Zhang “Characterization of nanostructured thermal interface materials—a review”, International Journal of Thermal Sciences, Volume 62, 2-11, 2012), (iv) aerogel layers or coatings for thermal insulation (see, for example, Kenneth McEnaney, Lee Weinstein, Daniel Kraemer, Hadi Ghasemi, Gang Chen, “Aerogel-based solar thermal receivers” Nano Energy, Volume 40, 180-186, 201) and (v) composite materials with dispersed conductive materials therein, which can have a tunable electrical and/or thermal conductivity so that they provide tunable electrical and/or thermal conduction pathways when the temperature of the carrier material falls below or above critical values (see, for example Ruiting Zheng, Jinwei Gao, Jianjian Wang, and Gang Chen, “Reversible temperature regulation of electrical and thermal conductivity using liquid-solid phase transitions” Nat Comm., 289, 2011, Published online at https://www.nature.com/articles/ncomms1288).

(11) Although the systems and techniques described herein have general applicability for EVs, they are particularly advantageous, and may be mission enabling, for untethered EVs operating in challenging environments, such as extreme hot, or cold, environments, airborne, Space, and long endurance missions, in which EVs and subsystems, may be required to operate for days, month, or even years.

(12) FIG. 1 depicts a holistic thermal management system for an EV, which includes energy input from an external source, for example the sun, thermal harvesting of this energy by an EV integrated sub-system, followed by selective transfer to an EV integrated storage sub-system, then it's selectable, or predictable, transfer to an EV subsystem which may require thermal energy to attain a desired operating temperature. Conversely, if the managed EV subsystem is required to expel thermal energy to attain a desired operating temperature, said energy can be selectively, or predictably, transferred to an integrated storage subsystem, where it may be retained for subsequent reuse or selectively, or predictably, transferred to an integrated thermal dissipation subsystem and from thence to the external environment. The selective, or predictable, transfer of thermal energy may be achieved by employing interconnects, backplanes, or other structures which can serve as conduits between the various subsystems, with, additional elements or interfaces which may be coupled, or uncoupled, to exhibit, directional or bi-directional, thermally conductive, or insulating behavior, in response a change in temperature, or by another activation means.

(13) More particularly, FIG. 1 shows a holistic, integrated, thermal management system 10 in an EV that includes a thermal energy storage subsystem 12, a thermal energy harvesting subsystem 14, a thermal energy dissipation subsystem 16, and a managed subsystem 18, along with their interconnections and optional harvesting, or dissipation, of thermal energy from, or to, the surrounding external environment (e.g., harvesting energy from an external energy source 13 such as the sun and dissipating energy to external thermal energy sink, such as the environment 11).

(14) FIG. 2 depicts an example of a multi-functional solar thermal harvesting skin which can be deployed across the surface, or frame, of an EV. Incident Sunlight 21 impinges on, and can penetrate, the outer layer(s) of the skin 22. Such layer(s) may be transparent, or functional layer(s), for example, de-icing, anti-icing, reflective, anti-reflective, PV, antenna or other functionality. The layer(s) may also impart a level of conversion of photon energy to thermal energy through various mechanisms. Examples of skins or films that may be suitable for skin 22 in certain embodiments may be found, for example, in U.S. Pat. Nos. 9,841,616, 9,802,711 and 9,570,795, which are each incorporated by reference herein in their entirety. These skins or films may incorporate different sublayers to perform such functions as de-icing, anti-icing, solar energy harvesting (by photovoltaic cells) and have a reflectivity that is tunable upon flexing.

(15) An underlying layer 23 is specifically designed to absorb and convert substantially all remaining light transmitted by layer 22 into thermal energy as well as being sufficiently thermally conductive to, and from, layer 22. Layer 23, may also provide local storage of thermal energy. Layer 24 is an interfacing layer, or backplane which provides a gateway for thermal energy transfer, from the thermal harvesting skin to a thermal storage medium, or device, through a selectively actuatable thermal energy transfer conduit 25, which may be directional, interruptible, switchable, selectable, or tunable. The conduit may be an integral part or the EV skin, frame, or another subsystem. Thermal energy may similarly be transferred in the reverse direction via the same, or another, selectively actuatable thermal energy transfer conduit 26 that is similar to conduit 25. Selection may be passively activated by temperature, another passive, or active, means. The selectively actuatable thermal energy transfer conduits 25 and 26 may be formed from the aforementioned composite materials with dispersed conductive materials therein, which can have a tunable electrical and/or thermal conductivity so that they provide tunable electrical and/or thermal conduction pathways that when the temperature of the carrier material falls below or above critical values. In this way selective thermal communication can be established between the components or subsystems that the conduits connect.

(16) The thermal storage medium 27, may be adjacent to, or remote from, the skin. It may incorporate a thermally conductive outer layer 24 and be connected to the skin though the conduit 25. The thermal storage medium can be similarly, but independently, interfaced to other devices or systems 28, such as batteries, which require thermal management. The storage medium may be isolatable, and ideally be designed to have sufficient heat capacity to support the accumulation, or release, of energy for the thermal management of the EV systems or components, throughout an EV mission.

(17) FIG. 3 depicts a multi-functional thermal storage system in which a structural element 31 of an EV is used as the storage medium. This may be realized with the unmodified structural element, or by modification of the structural element, for example with the incorporation of PCMs within the structure. Thermal interfacing of the structural component with other subsystems and components is accomplished with appropriate thermal interface layers 32 and selectively actuatable thermal energy transfer conduits 33 and 34, which may be an integral part or the EV, skin, frame, or another subsystem. The selectively actuatable thermal energy transfer conduits 33 and 34 may be formed from the aforementioned composite materials with dispersed conductive materials therein, which can have a tunable electrical and/or thermal conductivity so that they provide tunable electrical and/or thermal conduction pathways that when the temperature of the carrier material falls below or above critical values.

(18) FIG. 4 depicts a multi-functional thermal storage system in which an EV electro-chemical battery 41, comprising of an outer casing 42, electrolyte material 43, anode 44, cathode 45, and a conductive membrane 46 with appropriate thermal interface layers and selectively actuatable thermal energy transfer conduits 47 and 48. This is a particularly attractive solution since batteries frequently constitute a sizeable fraction of total EV mass.

(19) In one embodiment the invention provides a thermal management system which incorporates skins or films that are mechanically durable and which support solar thermal harvesting. These may be deployed across all available surface of an EV subject to solar illumination, representing the widest use application for solar harvesting skins.

(20) In other embodiments, skins with other designed functionalities, such as PV, or de-icing would incorporate, thermal harvesting and/or release functionality typically in layers below the aforementioned characteristics. In the instance of PV skins, thermal harvesting could be implemented directly from impinging sunlight or indirectly from thermal energy via the PV cells. A benefit in this instance would be to effect cooling of the PV cells for better performance. In the instance of de-icing, an express purpose could be the delivery of harvested and/or stored thermal energy to the de-icing layers.

(21) In other embodiments, thermal energy delivery, extraction, or both, may be required for the thermal management of specific systems or components under different conditions, for example batteries.

(22) In other embodiments, mission parameters may require the thermal management system to be designed to primarily heat EV systems and components. For example, in winter, artic or high-altitude conditions.

(23) In other embodiments, mission parameters may require the thermal management system to be designed to primarily cool EV systems and components and dissipate heat to the surroundings. For example, in tropical or summer conditions.

(24) As illustrated in FIG. 5, in some embodiments the thermal storage medium may comprise a centralized thermal storage element 50 in which single or multiple systems 55.sub.1, 55.sub.2 and 55.sub.3 which require thermal management may be connected to the storage element 50 via selectively actuatable thermal energy transfer conduits 59.sub.1, 59.sub.2 and 59.sub.3. The storage element is in selective thermal communication with thermal energy harvesting system 51 via selectively actuatable thermal energy conduit 56 and a thermal energy dissipation system 53 via a selectively actuatable thermal energy conduit 57.

(25) As illustrated in FIG. 6, in some embodiments the thermal storage medium may comprise a series of distributed thermal storage elements 60.sub.1, 60.sub.2 and 60.sub.3, which may be advantageously employed in the management of specific EV systems, based on their location and/or required management function, e.g. heating or cooling. Thus, in FIG. 6 each thermal storage element is in selective thermal communication via selectively actuatable thermal energy conduits to its own thermally managed system(s). In particular, thermal storage elements 60.sub.1, 60.sub.2 and 60.sub.3 are in selective thermal communication with thermally managed systems 62.sub.1, 62.sub.2 and 62.sub.3, respectively, via selectively actuatable thermal energy transfer conduits 64.sub.1, 64.sub.2 and 64.sub.3. The thermal storage elements 60.sub.1, 60.sub.2 and 60.sub.3 are themselves in selective thermal communication via selectively actuatable thermal energy conduits 65 and 66, with thermal energy harvesting system 61 and thermal energy dissipation system 63, respectively. In some cases, such as shown for thermal storage element 60.sub.2, the selective thermal communication with the thermal energy harvesting system 61 and/or the thermal energy dissipation system 63 may employ a path that includes another thermal storage element.

(26) FIG. 7 is a flowchart showing one example of a process for selectively communicating thermal energy using the techniques described herein between and among a thermal energy harvesting system 70, a thermal energy storage medium 71, thermally managed system 72 and thermal energy dissipating system 73.

Illustrative Examples

(27) Various use cases are briefly presented below

(28) Thermal managed sub-systems and/or components for High-Altitude, Long-Endurance (HALE) UAV EVs which are targeted for missions at stratospheric altitudes (20-30 km) of weeks, months, or even years duration. For such missions the primary energy source is typically PV solar. The electrical energy storage system is typically a Li-battery pack. The ambient temperature can be in the range of 210-220K. Daily solar insolation (equivalent peak sun hours per day) is both Latitude and seasonally dependent and is at a minimum during the winter solstice (which is for example 3 hr over New York City). Sufficient excess electrical energy has to be generated and stored during the shortest period of insolation of the mission to support continued UAV operations during the remainder of the day. This requirement effectively dictates the UAV design, including the size/required performance of the PV array and the size/energy density of the Li-battery pack. To date, the record HALE UAV endurance is approximately four weeks, in conditions of approximately 7 hours of daily insolation. The mission was terminated, after the battery performance degraded after daily cycling, under non-optimal conditions. This example illustrates a need for an improved power system performance which may, in part, be addressed by improved thermal management, for example (i) implementing coupled PV-battery thermal management practices, with selective distribution and optional intermediate thermal storage capability and/or (ii) integrating thermal energy storage materials, or functionality, into UAV structures such as the airframe in order to minimize added weight or size and/or (iii) integrating thermal storage materials, or functionality, within the battery itself, for similar reasons.

(29) Thermally managed batteries for potentially overheated conditions, with PCM materials dispersed, or integrated, within the battery components, namely the anode, cathode, electrolyte and/or the primary casing with optional and/or selectable interconnectivity to other EV subsystems, or components. These being distinct from batteries which simply have additional encapsulation containing PCM, which may have analogous functionality but at the expense of adding weight and size. In operation, the dispersed or integrated PCM may be selected to absorb thermal energy as the temperature of the battery increases towards a pre-selected upper limit, by undergoing a phase change, such as melting. The ability of the PCM to prevent the battery temperature from exceeding the limit being determined by the specific heat capacity and mass of the PCM and/or ability to additionally dissipate thermal energy from the PCM, or battery, by another thermally conductive pathway, for example a selectable thermal energy pathway to a storage or dissipation subsystem or component outside of the battery, which could be part of the EV structure.

(30) Thermally managed batteries for potentially undercooled conditions, with PCM materials dispersed, or integrated, within the battery components, namely the anode, cathode, electrolyte and/or the primary casing with optional and/or selectable interconnectivity to other EV subsystems, or components. These being distinct from batteries which simply have added encapsulation containing PCM, which may have analogous functionality but at the expense of added weight and size. In operation, the dispersed or integrated PCM may be selected to release thermal energy as the temperature of the battery decreases towards a pre-selected lower limit, by undergoing a phase change, such as solidifying. The ability of the PCM to prevent the battery temperature from dropping under the limit being determined by the specific heat capacity and mass of the PCM and/or ability to additionally absorb thermal energy from the PCM, or battery through another thermally conductive pathway, for example a selectable thermal energy pathway to another subsystem or component outside of the battery with deliverable thermal energy, which could be part of the EV structure.

(31) Integrated and selectively interconnected thermal storage components or sub-systems, which form all, or part, of the EV structure, for example structural frames, or skins. These may include dispersed, or integrated, PCMs, within porous, tubular or nanostructured structural elements, which structural elements provide the mechanical characteristics of the structure. The thermal storage media may include the structural elements themselves and/or PCMs which will enable the selective absorption, or release, of thermal energy from, or to, other interconnected subsystems, or components, when subject to heating or cooling through the transition points. The thermal storage components may further include aerogels or other structured layers for the purpose of thermal insulation/isolation from the surroundings.

(32) Integrated thermal energy conduction pathways or interconnects, which may be predictable, or selectable, are essential building blocks of the thermal energy management systems described herein. These may be variously integrated or interfaced, with the harvesting, dissipating, storing and/or thermally managed subsystems, or components, under consideration. Various materials, for example graphene, or other elemental carbon-based polymorphs, materials, in continuous, layered or nano-structured forms may be employed or composite materials containing these constituents. Such materials and structures are particularly attractive because of their generally high thermal conductivity, robustness and lightweight characteristics. Some parts of the thermal interconnection scheme may require thermal conducting pathways connecting components such as harvesting element and a remotely located thermal storage component. This might be provided by interconnections made from assembled graphene layers. Other parts may require the thermal interfacing of separate components and may be provided by a nanostructured carbon or metallic joining layers. Other parts may require a switchable, or interruptible, thermal connection which might be achieved within a composite material or structure in response to temperature changes. Thermal conduction pathways, thermal interfaces and interruptible elements may also be integral parts, or integrated within, EV structures, including skins or the frame or integral parts of other EV systems, or components, including batteries.

(33) Thermally managed PV arrays on EVs, with interconnections to thermal dissipation and/or storage systems, or components, are an area of great interest. PV arrays can generate substantial thermal energy during the harvesting of electrical energy from Sunlight, or other sources of radiation. The electrical harvesting efficiency of PV cells is higher at low temperatures for example a change of 10% or more may be observed over a range of 25° C.+/−50° C. range. The extraction of thermal energy from PV arrays is therefore a high priority. The same principles of selective thermal conduction and interconnection described in the above examples can be used in this case. In some instances, for instance low temperature environments, it may be more beneficial to store the extracted thermal energy and use this stored energy to maintain battery temperatures. In other instances, for instance high temperature environments, it may more beneficial to dissipate thermal energy to the environment from the surface of an EV.

(34) Microprocessor based sub-systems and components on an EV, can generate substantial thermal energy during operation which must be dissipated to maintain efficient subsystem or component operation. The extraction of thermal energy from such components is therefore a high priority. The same principles of selective thermal conduction and interconnection described in the above examples can be used in this case. In some instances, for instance low temperature environments, it may be more beneficial to store the extracted thermal energy and use the stored energy to maintain battery temperatures. In other instances, for instance high temperature environments, it may more beneficial to dissipate thermal energy to the environment from the surface of an EV.

(35) In the foregoing description, example aspects of the invention are described with reference to specific example embodiments thereof. The specification and drawings are accordingly to be regarded in an illustrative rather than in a restrictive sense. It will, however, be evident that various modifications and changes may be made thereto, in a computer program product or software, hardware, or any combination thereof, without departing from the broader spirit and scope of the present invention.

(36) In addition, it should be understood that the figures, which highlight the functionality and advantages of the present invention, are presented for illustrative purposes only. The architecture of the example aspect of the present invention is sufficiently flexible and configurable, such that it may be utilized (and navigated) in ways other than that shown in the accompanying figures.

(37) Although example aspects herein have been described in certain specific example embodiments, many additional modifications and variations would be apparent to those skilled in the art. It is therefore to be understood that the various example embodiments herein may be practiced otherwise than as specifically described. Thus, the present example embodiments, again, should be considered in all respects as illustrative and not restrictive.