Vehicle cabin thermal management system and method

Abstract

To provide a preferable vehicle cabin thermal management system and a vehicle cabin thermal management method.SOLUTION: A system can include an on-board thermal management subsystem. The system 100 may include an off-board (extravehicular) infrastructure subsystem. The on-board thermal management subsystem may optionally include: a battery pack; one or more fluid loops; and an air manifold. The system 100 may additionally or alternatively include any other suitable components.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Application No. 62 / 905,810, filed Sep. 25, 2019, which is incorporated by reference in its entirety.

[0002] The present invention relates generally to the field of thermal management, and more particularly to a new and useful vehicle cabin thermal management system and method in the field of battery technology. [Background technology]

[0003] In passenger vehicles, managing the temperature within the cabin environment is an important aspect of user comfort and well-being. However, the equipment required to properly condition the air adds mass to the vehicle, which can degrade vehicle performance. In addition, heating, ventilation, and air conditioning (HVAC) systems typically require power to operate that does not contribute to vehicle propulsion, which adds additional power capacity needs (and often mass in the form of battery weight or additional fuel) to the vehicle power system. These shortcomings can be particularly pronounced in the context of electric vehicles and / or aircraft, where weight and energy efficiency tradeoffs can have a significant impact on vehicle design. Summary of the Invention [Means for solving the problem]

[0004] Thus, there exists a need in the thermal management art to produce new and useful vehicle cabin thermal management systems and methods. The present invention provides such new and useful systems and methods. The present invention provides, for example, the following: (Item 1) 1. A system comprising: 1. An electric aircraft, comprising: a cabin defining an interior; Cabin air within the interior; an electric aircraft comprising: a plurality of battery cells onboard the electric aircraft; A refrigerant in a refrigeration system; a first fluid loop, a working fluid in the first fluid loop; and a first heat exchanger on-board the electric aircraft, the first heat exchanger fluidly connected to the cabin air; a condenser configured to thermally couple the working fluid to the refrigerant and transfer thermal energy from the refrigerant to the working fluid, the condenser being selectively fluidly coupled to the first heat exchanger; a second heat exchanger thermally coupled to the plurality of battery cells; an evaporator configured to thermally couple the working fluid to the refrigerant and transfer thermal energy from the working fluid to the refrigerant, the evaporator selectively fluidly coupled to the second heat exchanger; a first pump configured to circulate a working fluid in the first fluid loop; a first fluid loop comprising: A system comprising: (Item 2) Item 1. The system of item 1, further comprising a set of valves that, in a cooling mode, fluidly decouples the second heat exchanger from the first heat exchanger. (Item 3) The first and second heat exchangers each include an inlet port and an outlet port, the inlet port and the outlet port being fluidly coupled to a working fluid in the first fluid loop, and the set of valves includes: a cabin heating mode, wherein the set of valves connects an outlet of the second heat exchanger to an inlet of the first heat exchanger and an outlet of the first heat exchanger to an inlet of the second heat exchanger; a cabin cooling mode, wherein the set of valves connects an outlet of the second heat exchanger to an inlet of the second heat exchanger and connects an outlet of the first heat exchanger to an inlet of the second heat exchanger; and 3. The system according to item 2, wherein the system is operable between (Item 4) 4. The system of claim 3, further comprising a second pump, wherein in the cooling mode, a first portion of the working fluid is arranged in a first sub-loop comprising the first heat exchanger, a second portion of the working fluid is arranged in a second sub-loop comprising the second heat exchanger, and the first and second pumps are arranged in the first and second sub-loops, respectively. (Item 5) The set of valves a first end associated with an inlet of the first heat exchanger; and a second end associated with an outlet of the first heat exchanger; and a third end associated with the inlet of the second heat exchanger; and a fourth end associated with the outlet of the second heat exchanger; and 4. The system of claim 3, further comprising a four-way selector valve defining (Item 6) 2. The system of claim 1, wherein the refrigeration system is isolated from external airflow. (Item 7) 2. The system of claim 1, further comprising a fluid coupling configured to selectively connect the first fluid loop to a ground-based infrastructure comprising the working fluid. (Item 8) 8. The system of claim 7, wherein a charging mechanism is configured to fluidly connect the fluid coupling to the ground-based infrastructure and electrically connect the plurality of battery cells to the ground-based infrastructure. (Item 9) A first orifice defining an intake path from the exterior of the aircraft to the interior of the cabin; a nozzle defining an exhaust path from the interior of the aircraft to the exterior of the aircraft; an air compressor arranged along the exhaust path, the air compressor configured to increase pressure at the nozzle; and Item 1. The system of item 1, further comprising: (Item 10) 10. The system of claim 9, wherein the exhaust path passes over avionics equipment. (Item 11) a second working fluid in a second fluid loop; and a heat exchanger thermally connected to the plurality of battery cells, the second fluid loop extending through an interior of the heat exchanger; a second heat exchanger thermally connecting the second fluid loop to the first fluid loop; a second pump configured to circulate the second working fluid through the second fluid loop; and Item 1. The system of item 1, further comprising: (Item 12) 1. A method comprising: flying the electric aircraft, the electric aircraft comprising a cabin, cabin air within the cabin, and a battery pack; Cooling the cabin while flying the electric aircraft, comprising: transferring a first portion of thermal energy from the cabin air to a first working fluid in a first heat exchanger; transferring a first portion of the thermal energy from the first working fluid to a second working fluid in a second heat exchanger, the second working fluid being in thermal communication with the battery pack; storing a first portion of the thermal energy within a thermal mass of the battery pack; Including, A method comprising: (Item 13) 13. The method of claim 12, further comprising preconditioning the electric aircraft including replacing a first portion of the second working fluid with a second portion of the second working fluid from a ground infrastructure while the electric aircraft is grounded. (Item 14) The first working fluid is in a first fluid loop, and cooling the cabin further comprises: in response to determining satisfaction of a cabin temperature threshold, dividing the first fluid loop into a first sub-loop and a second sub-loop, a first portion of the first working fluid contained within the first sub-loop and a second portion of the working fluid contained within the second sub-loop, the first sub-loop comprising the first heat exchanger, and the second sub-loop comprising the second heat exchanger; transferring thermal energy from the first sub-loop to the second sub-loop using a heat pump; Item 13. The method according to item 12, comprising: (Item 15) Item 15. The method of item 14, wherein a total thermal energy of a thermal system comprising the battery pack, the first working fluid, the second working fluid, and the cabin air increases continuously during flight. (Item 16) and regulating a flow of outside air into the cabin during flight; Using a turbine to regeneratively charge the battery pack while simultaneously reducing the thermal energy of the flow. Item 13. The method according to item 12, comprising: (Item 17) 17. The method of claim 16, further comprising balancing the cabin air pressure with ambient pressure while flying the electric aircraft. (Item 18) venting a portion of the cabin air through the exhaust nozzle during flight; using a fan to increase one of the cabin air pressure at the exhaust orifice or the cabin air velocity at the exhaust orifice. Item 13. The method according to item 12, comprising: (Item 19) 20. The method of claim 18, further comprising, prior to ventilating the portion of the cabin air, blowing the portion of the cabin air across the avionics. (Item 20) Item 13. The method of item 12, wherein the battery pack comprises a first cell and a second cell, and cooling the cabin further comprises convectively balancing thermal energy between the first cell and the second cell using a third heat exchanger. (Item 21) 1. A system comprising: a cabin heat exchanger fluidly connected to an interior of the aircraft cabin; a battery heat exchanger thermally connected to a battery cell of the aircraft; 1. A condenser comprising: a condenser inlet fluidly connected to the battery heat exchanger by a working fluid; Condenser outlet and a condenser comprising: An evaporator comprising: an evaporator inlet fluidly connected to the cabin heat exchanger by the working fluid; Evaporator outlet and an evaporator comprising: A valve, a heating mode, wherein the valve fluidly connects the condenser outlet to the cabin heat exchanger and the evaporator outlet to the battery heat exchanger; a cooling mode, wherein the valve fluidly connects the condenser outlet to the battery heat exchanger and the evaporator outlet to the cabin heat exchanger; a valve selectively operable between A system comprising: (Item 22) 22. The system of claim 21, lacking a separate on-board active cooling system for the battery cells. (Item 23) A system configured to carry out the method according to any one of items 12-20. [Brief description of the drawings]

[0005] [Figure 1] FIG. 1 depicts a schematic diagram of the system.

[0006] [Diagram 2] FIG. 2 depicts a schematic diagram of an exemplary air manifold of the present system.

[0007] [Diagram 3] FIG. 3 depicts a schematic diagram of an exemplary air manifold in another embodiment of the system.

[0008] [Figure 4] FIG. 4 depicts a schematic diagram of an exemplary air manifold in another embodiment of the system.

[0009] [Diagram 5] FIG. 5 depicts a schematic diagram of an exemplary air-intake turbine in another embodiment of the system.

[0010] [Figure 6] FIG. 6 depicts a schematic diagram of an exemplary air-intake turbine in another embodiment of the system.

[0011] [Figure 7] FIG. 7 depicts a schematic diagram of another embodiment of the system in cabin heating mode.

[0012] [Figure 8] FIG. 8 depicts a schematic diagram of an alternative embodiment of the system in cabin cooling mode.

[0013] [Figure 9] FIG. 9 depicts a schematic diagram of an alternative embodiment of the system.

[0014] [Figure 10] FIG. 10 depicts a schematic diagram of an alternative embodiment of the system.

[0015] [Figure 11] FIG. 11 depicts a partial 3D view of another embodiment of the system.

[0016] [Figure 12]FIG. 12 depicts a schematic diagram of an exemplary battery temperature profile in accordance with another aspect of the method.

[0017] [Figure 13] FIG. 13 depicts a schematic diagram of an example battery state of charge profile for the variant of the method in FIG.

[0018] [Figure 14] FIG. 14 depicts a schematic diagram of an exemplary battery loop in another embodiment of the system.

[0019] [Figure 15] FIG. 15 depicts a schematic diagram of an exemplary battery loop in another embodiment of the system.

[0020] [Figure 16] FIG. 16 depicts a schematic diagram of an exemplary charger in another embodiment of the system.

[0021] [Figure 17] 17A-B depict schematic diagrams of an exemplary vehicle in an alternative embodiment of the method, in hover and forward moving configurations, respectively.

[0022] [Figure 18] FIG. 18 depicts a flow chart diagram of a vehicle cabin thermal management method.

[0023] [Figure 19] FIG. 19 depicts a flow chart diagram of an embodiment of the method.

[0024] [Figure 20] FIG. 20 depicts a flow chart diagram of an embodiment of the method.

[0025] [Figure 21] FIG. 21 depicts a schematic diagram of another embodiment of the system.

[0026] [Figure 22A] FIG. 22A depicts a schematic diagram of another embodiment of the system in cabin cooling mode.

[0027] [Figure 22B] FIG. 22B depicts a schematic diagram of another embodiment of the system in cabin heating mode. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] The following description of the preferred embodiments of the invention is not intended to limit the invention to those preferred embodiments, but rather to enable any person skilled in the art to make and use the invention. 1. Overview

[0029] System 100 can include an on-board thermal management subsystem. System 100 can optionally include an off-board (external) infrastructure subsystem. The on-board thermal management subsystem can include a battery pack, one or more fluid loops, and an air manifold. System 100 can additionally or alternatively include any other suitable components. An example of system 100 is shown in FIG. 1.

[0030] System 100 functions to manage the temperature of a vehicle cabin environment. System 100 may also function to manage airflow within the vehicle cabin environment. System 100 may additionally or alternatively have any other suitable functionality.

[0031] For short operating cycles (e.g., <40 minutes), electric vehicles can rely on the thermal mass of the battery to absorb and / or store the vehicle's waste heat during operation. In such an alternative, the vehicle can be used with off-board infrastructure while on the ground and / or charging to reduce the battery temperature. In a cabin heating mode, such a vehicle can utilize an on-board thermal management subsystem that uses waste heat generated by the battery during operation and / or stored (e.g., absorbed by the thermal mass) by the battery to heat the cabin. In a cabin cooling mode, the on-board thermal management subsystem can store excess heat from the cabin (air) in the battery, again utilizing the thermal mass of the battery (e.g., in addition to storing waste heat generated during battery operation in the battery). An example of an operating cycle (or trip) for a vehicle that relies on the thermal mass of the battery is shown in FIG. 12-13. However, the cabin environment (e.g., temperature, humidity, etc.) can be regulated differently.

[0032] In a first example embodiment, the on-board thermal management subsystem may include a plurality of battery cells on-board the electric aircraft, a refrigerant in a refrigeration system, a working fluid in a first fluid loop, the first fluid loop including a first heat exchanger (e.g., a cabin heat exchanger) on-board the electric aircraft, the first heat exchanger being fluidly connected to cabin air, a condenser thermally coupling the working fluid to the refrigerant, the condenser being fluidly coupled to the first heat exchanger, a second heat exchanger (e.g., a battery heat exchanger) thermally coupled to the plurality of battery cells, an evaporator thermally coupling the working fluid (e.g., in the cabin loop) to the refrigerant, the evaporator being fluidly coupled to the second heat exchanger, and a first pump configured to circulate the working fluid in the first fluid loop.

[0033] The system 100 can function to manage cabin temperature. Temperature management can include increasing the air temperature, decreasing the air temperature, maintaining the air temperature, and / or otherwise suitably manipulating the air temperature. Temperature management can additionally or alternatively include increasing, decreasing, maintaining, or otherwise suitably manipulating the temperatures of other parts of the cabin to improve user comfort, adjust the user environment (e.g., passenger seats, hand rests, foot rests, any other surface or object, etc.).

[0034] System 100 may additionally function to manage the thermal condition of the battery pack. The thermal condition may include the distribution of temperature within the battery pack, the average temperature of the battery pack, the rate of temperature rise or fall of the battery pack, and / or any other suitable metric that quantifies a temperature-related characteristic of all or a portion of the battery pack and / or thermally coupled elements.

[0035] The system 100 may also function to circulate a working fluid within the battery pack (e.g., to achieve temperature uniformity within the battery pack, to heat or cool the battery pack, etc.). The working fluid may be any suitable fluid that may be heated and / or cooled and flowed through a closed or open circuit of the battery loop to transfer heat between various components (including, for example, the external environment). The working fluid may additionally or alternatively be any suitable fluid medium for exchanging heat between portions of the battery pack and / or heat exchangers of the system 100. For example, the working fluid may be water, a water / glycol mixture (e.g., 50 / 50, 70 / 30, 80 / 20, etc.), a refrigerant (e.g., R134a), oil, air, a fluid coolant, mineral oil, any other suitable gas or gas mixture, and / or any other suitable fluid. Alternatively, the working fluid may be a non-hazardous, natural, or biodegradable fluid to minimize the environmental impact of a leak or spill. Alternatively, the working fluid can be non-conductive (e.g., mineral oil), which can eliminate the possibility of shorting out the electronics and / or allow for flood cooling of the battery cells 114 (e.g., in a fully flooded configuration). In some implementations, the system 100 can be configured to circulate multiple working fluids for various purposes (e.g., a first working fluid for cooling the battery pack circulated in parallel with a second working fluid for heating the battery pack, where the first and second working fluids can be circulated at different times depending on the needs of the thermal management system, etc.). Different fluid loops can use the same or different types of working fluids.

[0036] The system 100 can also function to detect and manage thermal events within the battery pack. A thermal event can include any off-nominal temperature reached by a portion of the battery pack. For example, a thermal event can include a thermal runaway in one or more cells 114 of the battery pack, where an uncontrolled positive feedback exothermic reaction occurs within a cell or cells. A thermal event can also include thermal propagation, where an off-nominal (e.g., spike, increase, etc.) temperature spreads from one cell to multiple cells that were initially unaffected. However, a thermal event can additionally or alternatively include any other temperature-related occurrence within the battery pack that requires mitigation to ensure proper battery pack operation (e.g., charging, discharging, storage, etc.).

[0037] The system, in various embodiments, may be used in conjunction with and / or include a number of associated systems, which may include aircraft, aircraft subsystems (e.g., powertrain subsystems, propulsion subsystems, avionics subsystems, etc.), ground-based vehicles (e.g., automobiles, locomotives, etc.), land-based infrastructure (e.g., air traffic control systems, ground-based maintenance systems, etc.), and / or any other suitable systems.

[0038] In a variation of system 100, portions of the system are distributed between the vehicle and the off-vehicle infrastructure subsystem. The vehicle preferably includes all portions of the vehicle cabin thermal management system that are used to regulate the temperature of the cabin environment during vehicle operation (e.g., flying, driving, etc.). The infrastructure equipment preferably includes portions of the system that are used to prepare the cabin thermal conditioning system for operation (e.g., recharging, thermally preconditioning, precooling on-board thermal management subsystem components to a ready state prior to vehicle operation, etc.). This distribution serves to allow for thermal conditioning of the vehicle cabin while reducing the overall mass and / or energy capacity requirements of the vehicle by offloading the utilization of heavy and / or high-power thermal management equipment to the infrastructure equipment. The infrastructure equipment can be static (e.g., fixed on the ground as part of a substantially permanent infrastructure) or mobile (e.g., mobile / towable trailers that can be transported to service areas and connected to the vehicle during charging or other thermal conditioning).

[0039] 18, method 200 includes determining a temperature set point for the battery pack S100, regulating the battery pack temperature to the temperature set point S150, and regulating the cabin air temperature using the cabin thermal management system S300. The method may additionally or alternatively include determining a temperature of the battery pack S200 and redistributing heat within the battery pack based on the temperature of the battery pack S250. Method 200 may additionally or alternatively include any other suitable processes.

[0040] Method 200 functions to prepare a vehicle's cabin thermal management subsystem for operation and to facilitate cabin temperature regulation during vehicle operation, however, method 200 may additionally or alternatively have any other suitable functionality.

[0041] In one embodiment, the method can include cooling a cabin while flying the electric aircraft, the cooling comprising transferring a first portion of thermal energy from cabin air to a first working fluid (e.g., in a cabin fluid loop) in a first heat exchanger (e.g., a cabin heat exchanger), transferring the first portion of thermal energy from the first working fluid to a second working fluid (e.g., in a battery loop) in a second heat exchanger (e.g., a battery heat exchanger), the second working fluid in thermal communication with a battery pack, and storing the first portion of thermal energy in a thermal mass of the battery pack. Additionally, the method can include preconditioning the aircraft while the electric aircraft is grounded, the preconditioning comprising replacing a second portion of the second working fluid with a first portion of the second working fluid from ground infrastructure.

[0042] Method 200 is preferably implemented and / or performed using a system substantially similar to system 100. However, method 200 may be implemented and / or performed by any other suitable system involving any other suitable components that may be used for vehicle cabin thermal management.

[0043] The vehicle cabin thermal management system 100 and / or method 200 are preferably implemented in conjunction with an aircraft (e.g., the system may include an aircraft), and in variants where the system is distributed between the vehicle 101 and the infrastructure facilities 104, the vehicle is preferably an aircraft. In particular, the aircraft is preferably a rotorcraft, but may additionally or alternatively include any suitable aircraft. The aircraft is preferably a tilt rotor aircraft with multiple aircraft propulsion systems (e.g., rotor assemblies, rotor systems, etc.) operable between a forward arrangement (an example is shown in FIG. 17B) and a hovering arrangement (an example is shown in FIG. 17A). However, the aircraft may alternatively be a fixed wing aircraft with one or more rotor assemblies or propulsion systems, a helicopter with one or more rotor assemblies (e.g., at least one rotor assembly or aircraft propulsion system is generally axially oriented and provides horizontal thrust), and / or any other suitable rotorcraft or vehicle propelled by rotors (and / or propellers). The aircraft preferably includes an all-electric powertrain (e.g., battery-powered electric motor) driving one or more propulsion assemblies, but may additionally or alternatively include hybrid powertrains (e.g., gas-electric hybrids including internal combustion generators), internal combustion powertrains (e.g., including gas turbine engines, turboprop engines, etc.), and any other suitable powertrains.

[0044] In a specific embodiment, portions of the vehicle cabin thermal management system are integrated into an electric tilt rotor aircraft as described in U.S. Application No. 16 / 409,653, filed May 10, 2019, which is incorporated by reference herein in its entirety, however, any other suitable aircraft may be used.

[0045] The term "rotor" as utilized herein in connection with portions of system 100, method 200, or otherwise, may refer to a rotor, a propeller, and / or any other suitable rotary aerodynamic actuator. A rotor may refer to a rotary aerodynamic actuator utilizing an articulating or semi-rigid hub (e.g., the blade connection to the hub can be articulated, flexible, rigid, and / or otherwise connected), and a propeller may refer to a rotary aerodynamic actuator utilizing a rigid hub (e.g., the blade connection to the hub can be articulated, flexible, rigid, and / or otherwise connected), although such distinctions are not made explicit or implied as used herein, and use of "rotor" may refer to either configuration and any other suitable configuration of articulating or rigid blades, and / or any other suitable configuration of blade connection to a central member or hub. Similarly, use of "propeller" may refer to either configuration and any other suitable configuration of articulating or rigid blades, and / or any other suitable configuration of blade connection to a central member or hub. Thus, a tilt rotor aircraft may be referred to as a tilt propeller aircraft, a tilt prop aircraft, and / or is otherwise suitably referred to or described.

[0046] In a specific embodiment of the vehicle cabin thermal management system, portions of the system are integrated into an electric tilt-rotor aircraft that includes multiple tiltable rotor assemblies (e.g., six tiltable rotor assemblies). The electric tilt-rotor aircraft can operate as a fixed-wing aircraft, a rotary-wing aircraft, and in any limit configuration between fixed-wing and rotary-wing conditions (e.g., one or more of the multiple tiltable rotor assemblies are oriented in a partially tilted state). A control system for the electric tilt-rotor aircraft, in this embodiment, can function to command and control the multiple tiltable rotor assemblies in and / or between fixed-wing (e.g., forward flight configuration) and rotary-wing (e.g., hover configuration) configurations.

[0047] In a variant, the system 100 and method 200 regulate the vehicle cabin environment in relation to various defined temperature values, including a setpoint temperature, a cabin temperature, and an ambient temperature. A setpoint temperature is a temperature value commanded by a user and / or passenger (e.g., via an in-vehicle control interface, a predefined value, etc.). A cabin temperature is a measured temperature of the cabin air volume (e.g., where an occupant is seated or otherwise suitably positioned during an operating session of the vehicle). An ambient temperature is a temperature value of an external environment proximate to the vehicle. Additionally or alternatively, other temperature values ​​may be suitably defined in any other suitable manner. 2.Profit

[0048] Variations of this technology may provide several benefits and / or advantages.

[0049] First, variations of the technology can reduce vehicle mass by arranging substantial portions of the system on off-vehicle infrastructure equipment. For an equivalent vehicle mass, this can also enable higher overall energy capacity and therefore range and / or power output (e.g., by replacing portions of a thermal conditioning system that would otherwise be carried with the vehicle with additional battery pack mass). For example, the off-vehicle infrastructure equipment can "pre-cool" the on-board components of the system prior to vehicle operation (e.g., pre-load the system with thermal capacity to heat and / or cool the cabin environment), allowing the on-board components to maintain vehicle cabin temperatures during vehicle operation across a wider temperature range and / or with greater efficiency than would be achievable without prior thermal capacity expansion and / or by otherwise including the required components on-board the vehicle.

[0050] Second, variations of the present technology can utilize the vehicle battery pack thermal capacity during operation as part of an onboard cabin conditioning subsystem (e.g., as shown in FIG. 9) to improve the efficiency of a given onboard subsystem. For example, heat generated as the battery pack discharges during vehicle operation can be exchanged with airflow through the onboard thermal management subsystem during operation, adding heat to the cycle (and / or cabin). In another embodiment, heat from the airflow through the vehicle cabin can be transferred to a working fluid flowing through the battery conditioning system, utilizing the excess thermal capacity of the battery pack as a heat sink to cool the vehicle cabin.

[0051] Third, variations of the technology can intelligently manage vehicle cabin thermal conditions relative to a set point during vehicle operation according to dynamic mission objectives and / or evolving constraints on vehicle cabin temperature. For example, the technology can respond to a change in mission objective from "proceed to destination" (e.g., nominal operation) to "emergency landing" automatically by ceasing active regulation of the vehicle cabin (e.g., cooling or heating) and reserving vehicle energy for propulsion and control operations. In another example, the technology can respond to changes in flight conditions (e.g., remaining distance to destination, remaining time to destination, remaining flight profile electrical discharge or power requirements, ambient temperature, etc.) automatically by adjusting aspects of the thermal management control loop (e.g., control loop rise time, set point temperature, heat transfer rate, etc.).

[0052] Fourth, variations of the present technology can optimize the distribution of vehicle cabin thermal management system components between the on-board thermal management system and infrastructure equipment to reduce the mass of the vehicle. The overall mass of a vehicle can include, for example, the dry weight of all components of the on-board thermal management subsystem, the full weight of the coolant used, and the weight equivalent of the power consumption required by the on-board thermal management subsystem (e.g., the kW to kg ratio of added mass in the form of battery weight, such as 0.52 kW to 1 kg or any other suitable ratio).

[0053] Fifth, variations of the present technology can be designed to minimize noise within the cabin. For example, the compressor and other moving parts of the on-board thermal management subsystem can be sized (e.g., by physical size, by volume, etc.) to produce a lower noise level along with the rest of the on-board thermal management subsystem, even while slightly reducing the cooling and / or heating capacity of the on-board thermal management subsystem. On-board thermal management subsystem noise is preferably minimized in the expected and / or actual location of the vehicle occupants during vehicle operation. However, noise can additionally or alternatively be minimized in any other suitable location inside or outside the vehicle during any other period during or outside vehicle operation. In such variations, noise is preferably kept below a threshold (e.g., 55 dBA), but can additionally or alternatively be kept below any other suitable value.

[0054] Sixth, variations of the present technology may eliminate or reduce the amount of ambient air that may otherwise need to flow through the vehicle to provide a heat source or heat sink for the separate heating or cooling required to maintain the comfort and safety of the vehicle cabin occupants. This reduction in air flowing through the vehicle may reduce vehicle drag and power consumption and may allow for an increase in vehicle range or payload.

[0055] However, variations of the system may additionally or alternatively provide any other suitable benefits and / or advantages. 3. System

[0056] System 100 may include an on-board thermal management subsystem 102. System 100 may optionally include an off-board (external) infrastructure subsystem 104. System 100 may additionally or alternatively include any other suitable components. An example of system 100 is shown in FIG.

[0057] The on-board thermal management subsystem may include a battery pack 110, one or more fluid loops 120, and an air manifold 140. The on-board thermal management subsystem may additionally or alternatively include any other suitable components.

[0058] The on-board thermal management subsystem functions to thermally condition the cabin environment to achieve a cabin setpoint temperature. Thermally conditioning the cabin can include utilizing waste heat from the battery to heat the cabin and / or cabin air in a cabin heating mode. Thermally conditioning the cabin can additionally include relying on the thermal mass of the battery to transfer heat to the battery (and / or battery loop) and act as a heat sink for thermal energy from the cabin to cool the cabin and / or cabin air in a cabin cooling mode. The on-board thermal management subsystem can additionally function to pre-condition the cabin prior to takeoff. However, the on-board thermal management subsystem can additionally or alternatively have any other suitable functionality.

[0059] The on-board thermal management subsystem may include a battery pack, which functions to store energy to power vehicle operation (e.g., sustain flight). The battery pack may additionally or alternatively function to provide power to components of the system (e.g., pumps, fans, compressors, etc.). Alternatively, the battery pack may additionally function to generate thermal energy, which is used to thermally condition the cabin in a heating mode. Alternatively, the battery pack and / or individual cells therein may additionally function to store a portion of the thermal energy removed from the cabin air and / or generated by another battery of the aircraft during battery operation. In an embodiment, the thermal energy may be stored by the battery pack for more than a threshold period (e.g., 10 minutes, 30 minutes, flight duration).

[0060] The energy stored by the battery pack is preferably stored in the form of chemical potential energy and discharged in the form of electrical energy. However, energy may additionally or alternatively be stored and / or discharged in any suitable form. In particular examples, the battery may store thermal energy and chemical energy and discharge both thermal energy and chemical energy to thermally condition the cabin (e.g., in a heating mode). Operation of the battery pack may include charging the battery pack, discharging the battery pack, and / or maintaining a charge on the battery pack (e.g., storing energy). However, operation of the battery pack may include any other suitable use of the battery pack.

[0061] The battery packs can be located on-board the vehicle, arranged in, on, or otherwise suitably coupled to the vehicle. Thus, the battery packs move (e.g., are transported) with the vehicle as it moves. The system can include any suitable number of battery packs. The system can include one battery pack per propulsion system, one battery pack associated with multiple propulsion systems, one propulsion system associated with multiple battery packs, multiple battery packs (e.g., two, three, four, more than four, etc.) on-board the vehicle, a single battery pack for the vehicle, and / or any other suitable number of battery packs associated with any number of aircraft components. The battery packs can have any suitable arrangement and can be located in the fuselage, empennage, wings, cabin (e.g., below the passenger area), tail, nacelle, and / or any other suitable area. Preferably, the batteries are distributed symmetrically about the center of the aircraft, but may additionally or alternatively be offset a predetermined distance (e.g., 1 meter, 2 meters, >2 meters, etc.) from a passenger area, another battery, rotor disk, rotor disk surface, and / or any other suitable vehicle component, and / or otherwise distributed about the vehicle. For example, the system may include one battery pack per propulsion unit (or other suitable load) that powers an associated electric motor. In another example, the system may include a single battery pack connected to each propulsion unit (e.g., an automotive vehicle with a single battery pack and a single integrated powertrain including multiple motors). In further examples, the system may include a number of battery packs greater than the number of propulsion units, a number of battery packs less than the number of propulsion units, and / or any suitable number of battery packs. The battery packs may be interconnected with the powered components of the vehicle in any suitable manner (e.g., multiple battery packs connected to each powered component for redundancy in a fault-tolerant power network).

[0062] A battery pack can include multiple cells in any suitable arrangement (eg, parallel, series, etc.) that cooperate to form a battery pack.

[0063] The battery pack and its cells can store electrochemical energy in a rechargeable manner using a variety of battery chemistries. For example, the battery pack can store a wide variety of electrochemical batteries, including aluminum-ion batteries, carbon batteries (e.g., single carbon batteries, dual carbon batteries, etc.), flow batteries (e.g., vanadium redox batteries, zinc-bromine batteries, zinc-cerium batteries, etc.), lead-acid batteries (e.g., deep cycle batteries, VRLA batteries, AGM batteries, gel batteries, etc.), glass batteries, lithium-ion batteries (e.g., lithium-ion lithium cobalt oxide batteries, lithium-ion manganese oxide batteries, lithium-ion polymer batteries, lithium iron phosphate batteries, lithium-sulfur batteries, lithium titanate batteries, thin-film lithium-ion batteries, lithium ceramic batteries, etc.), magnesium-ion batteries, metal-air electrochemical batteries (e.g., lithium-air batteries, aluminum-air batteries, germanium-air batteries, calcium-air batteries, iron-air batteries, potassium-ion batteries, The battery may be a silicon-air battery, a zinc-air battery, a tin-air battery, a sodium-air battery, a beryllium-air battery, etc.), a molten salt battery, a nickel-cadmium battery (e.g., a vented cell nickel-cadmium battery), a nickel metal hydride battery, a nickel-iron battery, a nickel metal hydride (NiMH) battery, a nickel-zinc battery, an organic radical battery, a polymer-based battery, a polysulfide bromine battery, a potassium-ion battery, a rechargeable alkaline battery, a rechargeable fuel battery, a sand battery, a silicon-air battery, a silver-zinc battery, a silver-calcium battery, a sodium-ion battery, a sodium-sulfur battery, a solid-state battery, a ferrate cathode battery (e.g., a super iron battery), a zinc-ion battery, and / or any other suitable battery utilizing any other suitable chemistry for the storage and release of electrical energy.Additionally or alternatively, the battery pack may include a capacitive energy storage unit, such as a capacitor, a supercapacitor, and / or any other suitable means for storing and discharging electrical energy in a controllable manner.

[0064] The battery pack may include any suitable energy storage capacity, which may be <10 kWh, 10 kWh, 25 kWh, 35 kWh, 50 kWh, 80 kWh, 100 kWh, 150 kWh, >150 kWh, any suitable range defined by the aforementioned values, and / or any other suitable storage capacity. Preferably, the charge rate of the battery pack (and / or individual cells within the battery pack) is limited to 2C, but may alternatively be <1C, 1C, 1.5C, 2.5C, 3C, 5C, >5C, and / or any other suitable charge rate.

[0065] However, the system may include any other suitable battery pack.

[0066] The battery cells may have any suitable electrical and / or power characteristics. The battery cells may operate at any suitable voltage (e.g., 2.4V, 4.2V, nominal, maximum, minimum, etc.), charge current, discharge current, C-rate, energy capacity, temperature range, and / or have any other suitable characteristics. In a specific embodiment, each battery cell in the battery pack is arranged in series. In a second specific embodiment, two sets of battery cells (series) in the battery pack are arranged in parallel. The battery cells in the battery pack collectively generate a pack voltage, which may be <100V, 240V, 350V, 400V, 450V, 600V, >600V, any range bounded by the aforementioned values, and / or any other suitable pack voltage.

[0067] The battery cells inside the battery pack can have any suitable geometric shape and / or arrangement. The battery cells can be cylindrical, button-shaped, prismatic, pouch-shaped, and / or any other suitable geometric shape. The battery cells are preferably arranged in multiple cell arrays (examples are shown in FIG. 14 and FIG. 15), but can also be arranged in a single array or arranged otherwise. The battery pack can include insulation between cells in the same array (e.g., interleaved between cells), adjacent cell arrays (e.g., interleaved between arrays), and / or any other suitable set of cells. The insulation can be made from any suitable material, such as polyurethane, cellulose, fiberglass, carbon fiber, polystyrene, metal, plastic, and / or any other suitable insulating material. In specific examples, the cell arrays can include 12 cells, 24 cells, 28 cells, 32 cells, 36 cells, and / or any other suitable number of cells per pack and / or battery heat exchanger (e.g., cold plate, heat sink). Alternatively, the top, bottom, and / or sides (cylindrical, arcuate, wide, and / or narrow) of the battery cells can be thermally interfaced with a fluid loop (e.g., battery loop, cabin loop) in a heat exchanger (heat sink, etc.). The thermal interface can be arranged on the side of the cell array opposite the insulation, adjacent to the insulation, on the bottom with the insulation on the side, on the side with the insulation on the bottom, interlaced between the cell array, interlaced between the cells, and / or otherwise arranged relative to the cells and / or insulation. The battery cells are preferably fluidly isolated from the working fluid in the fluid loop (e.g., the working fluid flows through a thermally conductive fluid manifold, flows through a hollow heat sink, etc.), but can alternatively be fluidly connected to the working fluid.

[0068] In another embodiment, a heat sink (e.g., a chill plate) is arranged in thermal contact with the first and second cells of the battery pack. The heat sink can convectively balance thermal energy between the first and second cells and / or distribute thermal load between the first and second cells. In another embodiment that includes insulation (e.g., between adjacent cells), the thermal resistance from the first cell to the second cell through the insulation exceeds the thermal resistance from the first cell to the second cell through the heat sink (and / or the working fluid circulating therethrough).

[0069] However, the battery may include any other suitable set of cells in any suitable arrangement.

[0070] The battery pack may include battery electronics 112, such as a battery management system (BMS). The battery electronics may be coupled to one or more battery packs (e.g., with a 1:1, 1:N, or N:1 battery electronics to battery pack relationship). The battery electronics may function to monitor the status of the battery pack. The status of the battery pack may include state of charge (SoC), state of health (SoH), state of power (SoP), state of safety (SoS), temperature (e.g., pack temperature, cell temperature, cell array temperature, working fluid temperature, cell temperature distribution, etc.), and / or any other suitable characteristics. The battery electronics may also function to report the status of the battery pack to other components of the battery thermal management system. The battery electronics may also function to control charging and / or discharging of the battery pack (e.g., based on commands from a vehicle operator or a computerized vehicle operating system). The battery electronics may additionally function to control on-board thermal management subsystems and / or off-board infrastructure subsystems.

[0071] The battery electronics may include one or more sensors. The sensors of the battery electronics function to measure parameters of the battery pack during operation. The sensors may measure electrically related parameters of the battery pack (e.g., current flowing through the battery pack, voltage of the battery pack, state of charge of the battery pack, etc.), thermal parameters of the battery pack (e.g., temperature at any suitable point within the battery pack, temperature outside the battery pack, rate of temperature change at any suitable point within or around the battery pack, etc.), flow rate of a working fluid through the battery pack (e.g., through a heat sink), and / or any other suitable parameters. Any suitable sensor type or modality may be utilized to measure the aforementioned parameters (e.g., current probes, shunts, thermocouples, thermistors, etc.). The battery electronics may include a communication module (wired or wireless) configured to communicatively connect to an on-board pump, a vehicle controller, off-vehicle infrastructure (e.g., on-board pump, battery charger, on-board cooling system, etc.), and / or any other suitable vehicle component / endpoint.

[0072] The battery electronics can be cooled by the same system and / or different cooling components as the battery cells 114. The battery electronics can be air-cooled (e.g., fluidly connected to an air manifold, an exhaust path of the air manifold extending across the battery electronics, etc.), connected to a separate heat exchanger (e.g., a heat sink), thermally connected to the airframe, and / or otherwise cooled separately from the battery cells, thereby reducing the thermal load on the battery thermal management system. The battery electronics can be powered by the battery pack that it controls and / or powered by a separate battery pack.

[0073] However, the system may include any other suitable battery electronics and / or otherwise suitably control, monitor and / or regulate the battery.

[0074] The on-board thermal management subsystem may include one or more air manifolds, which function to connect the vehicle (cabin) interior 105 to the vehicle exterior 106 and regulate the airflow therebetween. An exemplary air manifold is shown in FIG. 11. The air manifold may include any suitable ducts, tubing, plumbing, vents, baffles, valves, and / or other suitable components that direct cabin air throughout and / or around the cabin 108 (e.g., through the aircraft housing). The air manifold may include rigid, semi-rigid, and / or flexible components. However, the air manifold may additionally or alternatively include any other suitable components. In a first variation, the inlet and outlet orifices are defined by a fluidly continuous air manifold (e.g., the air manifold may be fluidly connected to the cabin interior). In a second variation, the inlet and outlet orifices are defined by inlet and outlet air manifolds, respectively, both of which are fluidly connected to the cabin interior. However, the air manifolds may be configured differently.

[0075] The air manifold may include one or more external orifices, which fluidly connect cabin air (within the cabin) to ambient air and define an air flow path therebetween. The external orifices may include an inlet orifice 141, which functions to draw ambient air into the air manifold. The inlet orifices may be arranged relative to the vehicle in any suitable manner. Preferably, the inlet orifices are located proximate the front and / or front end of the vehicle (e.g., closer to the front than the rear). However, the inlet orifices may alternatively be located proximate the vehicle's propulsion system, proximate the vehicle's on-board avionics, on an upper surface of the vehicle (e.g., an example is shown in FIG. 3), on an underside surface of the vehicle (e.g., an example is shown in FIG. 2), in a high pressure aerodynamic region of the vehicle (e.g., near the leading edge of the airfoil body), in a low pressure aerodynamic region of the vehicle (e.g., above the airfoil body), and / or otherwise suitably arranged. The inlet orifice is preferably aligned with the external airflow (e.g., defines a central axis aligned with the longitudinal / roll axis of the aircraft and / or otherwise suitably oriented) toward the external airflow such that the inlet orifice directs airflow from the exterior of the vehicle into the interior of the air manifold. However, the inlet orifice can be oriented otherwise. The air manifold preferably includes a single inlet orifice (e.g., with redundant fans arranged sequentially therein, an example is shown in FIG. 4), however, can include multiple redundant inlet orifices and / or any other suitable number of inlet orifices.

[0076] The external orifices can include an exit orifice 142, which functions to exhaust cabin air into the surrounding environment. The exit orifice can thus allow for periodic and / or sustained exhaust of gases (such as CO2 produced by passengers) from the vehicle in compliance with regulatory standards. In a specific embodiment, cabin air can be completely exhausted from the exit orifice (and replenished through the inlet orifice) every two minutes. The exit orifice can be arranged in any suitable manner with respect to the vehicle. Preferably, the exit orifice is arranged along the underside surface of the vehicle (e.g., an embodiment is shown in FIG. 2) and / or adjacent to the rear of the vehicle (e.g., closer to the rear than the front, an embodiment is shown in FIG. 3), however, the exit orifice can alternatively be arranged on the upper surface of the vehicle, in a high pressure aerodynamic region of the vehicle (e.g., near the leading edge of the airfoil body), in a low pressure aerodynamic region of the vehicle (e.g., above the airfoil body), and / or otherwise suitably arranged. The exit orifice is preferably oriented (e.g., within 15 degrees) along the direction of airflow (e.g., during forward flight), aligned in a direction opposite the inlet, and / or otherwise suitably oriented. The exit orifice can have any suitable geometry. The exit orifice geometry can include tapering in the direction of airflow out of the orifice (e.g., a nozzle that narrows toward the rear of the vehicle), one or more slots (e.g., extending the entire length), rounded holes, rectangular openings, and / or any other suitable geometry. The air manifold preferably includes a single exit orifice, however, it can also include multiple redundant exit orifices, one exit orifice per inlet orifice, and / or any other suitable number of exit orifices.

[0077] However, the air manifold may include any other suitable external orifices.

[0078] The air manifold may include interior vents 143, which function to direct cabin air, such as toward passengers and / or cabin components requiring thermal conditioning (e.g., windows). The air manifold may include any suitable number of interior vents, such as one per passenger / seat, multiple per passenger / seat, a single vent directing air toward multiple passengers / seats, and / or any other suitable number of interior vents. The interior vents may optionally include anti-fog vents arranged along a window, such as a windshield. In such an alternative, the interior vents function to vent waste heat (e.g., from the battery and / or avionics) toward the window to reduce condensation and improve optical connection through the window to the vehicle exterior. In one embodiment, the interior vents may include slots that extend along the base of the windshield and connect the windshield to the air manifold. The slots can be selectively connected to an exhaust path (e.g., after the air has passed over the avionics, the air can be exhausted through the slots and back into the cabin as an alternative to exhausting the air out of the aircraft) and / or a cabin heat exchanger (e.g., in parallel with heating the cabin via the remainder of the interior vents as a primary form of cabin heating). The air manifold can optionally include an interior air (cabin air) intake 144, which functions to allow for recirculation of cabin air. The interior air intakes can be arranged along the floor, front, back, and ceiling of the vehicle interior. The air manifold can include any suitable number of interior air intakes, which can include one interior intake per interior vent, multiple interior intakes for a single interior vent, and / or a single interior intake associated with multiple interior vents.

[0079] The on-board thermal management subsystem may define any suitable air flow path for the cabin air (e.g., along the ducts of the air manifold). The air manifold may establish and / or fluidly connect air flow paths between an inlet orifice and an outlet orifice, an inlet orifice and an interior vent, an interior intake and an interior vent, an interior intake and an outlet orifice (known as an outlet flow path), an interior intake and a cabin heat exchanger, an inlet orifice and a cabin heat exchanger (known as an inlet flow path), a cabin heat exchanger and an interior vent, and / or any other suitable flow paths. In another embodiment, a portion of the air manifold (e.g., one or more of the aforementioned flow paths) is thermally connected to the on-board electronics and / or fluidly coupled to the on-board electronics (e.g., battery electronics, avionics, flight computers, heat generating electronics, etc.). In an alternative embodiment, it may be advantageous to fluidly connect the on-board electronics along the exhaust path between the interior air intake and the outlet orifice (e.g., fluidly connecting the on-board electronics to the exhaust cabin air). In such an alternative embodiment, the heat load applied by the on-board electronics to the on-board thermal management system is in series with (and follows sequentially after) the cabin environment. When the ambient temperature exceeds the cabin temperature, this results in more efficient cooling of the on-board electronics than direct ambient cooling. Additionally, such an alternative embodiment may minimize the volume of air passing through the inlet orifice, since the same volume of air may be used for both cabin conditioning and cooling of the on-board electronics.

[0080] In one embodiment, an aircraft processor is arranged within the housing and thermally connected to a heat sink. An air manifold exhaust duct connects the interior of the aircraft cabin to the housing and the housing to an exit orifice, with an exhaust path passing through the interior of the housing. Cabin air vented along the exhaust path passes over the heat sink and cools the processor and removes heat generated by the processor from the aircraft by forced air convection. In this embodiment, cooling of the processor may occur without providing additional heat load to the aircraft cabin while utilizing air manifold components.

[0081] In a second embodiment, the avionics are arranged below the glare shield, which can reduce solar heat loads on the avionics. The exhaust air in the exhaust path is blown by the air manifold below the glare shield and across the avionics before being exhausted from the vehicle (e.g., directed out of a rear-facing nozzle).

[0082] However, the on-board electronics may alternatively be cooled using an air manifold or by separate components.

[0083] The air manifold may include fans 145, which function to increase air velocity and / or pressure within various portions of the air manifold. The fans may additionally function to transport air through the air manifold. The air manifold may include any suitable type of fan. The fans may be air compressor, centrifugal, cross-flow, axial flow, blower fan, air mover, impeller, and / or any other suitable type. The fans are preferably blown through the interior of the air manifold, but may alternatively be operated unencapsulated or without a fan shroud. The fans may be of any suitable size and / or power. In a specific embodiment, each fan along the air inlet / exhaust path is individually sized to completely displace a volume of cabin air within a threshold period (e.g., 2 minutes). In a second embodiment, the fans may be 100 W. The fans may have any suitable arrangement within the air manifold. The fans may be arranged in series along a single air flow path (eg, through an external air inlet and / or outlet) and / or in parallel along separate (eg, adjacent, redundant) ducts.

[0084] Fans can be arranged along the external orifices (e.g., inlet, outlet) and / or internal vents / intakes. Alternatively, it may be advantageous to pressurize and / or accelerate the exhaust cabin air out of the exit orifice to reduce pressure drag at the exhaust orifice (e.g., for a depressurized cabin). In a specific example, applying 100 W of power to a fan or other air compressor along the exhaust flow path can offset 1 kW of thrust that would otherwise be required to counter the drag created by the low exit velocity of the air at the exit orifice.

[0085] The fan may be arranged along the interior flow path to regulate cabin air recirculation and / or direct air towards passenger seats. The fan may be located in an air manifold duct proximate to an interior vent (e.g., bypassing an interior vent / intake), and / or otherwise suitably arranged. In particular embodiments, the fan may be mounted to and / or integrated with a liquid-to-air heat exchanger (e.g., a cabin heat exchanger). In a second alternative, the fan may blow cabin air through the liquid-to-air heat exchanger.

[0086] The air manifold may optionally include a set of valves that function to selectively couple (and / or isolate) cabin air from outside the cabin. The air valves may be arranged along the cabin intake path, the exhaust path, and / or the cabin air recirculation path. The air valves may include throttle valves, check valves, binary position valves (e.g., stop / start valves), linear valves, rotary valves, solenoid valves, ball valves, butterfly valves, directional / directional valves, and / or any other suitable type of valve.

[0087] The air manifold may optionally include a filter 149 (eg, a HEPA filter, etc.) disposed along the inlet pathway proximate to the inlet orifice (eg, before the air first enters the cabin).

[0088] Cabin air within the air manifold and cabin environment can be pressurized or depressurized such that cabin pressure exceeds ambient pressure. The depressurized cabin air can be balanced and / or otherwise depressurized to within a threshold percentage of ambient pressure, such as within 5%, within 10%, etc. Alternatively, for short cycle, electric, and / or urban aircraft, utilizing a depressurized cabin can eliminate structural / weight penalties associated with a pressurized cabin, thereby increasing vehicle efficiency and range. Thus, balancing cabin pressure with ambient pressure can increase and improve the efficiency of the vehicle and / or onboard thermal management subsystems.

[0089] Alternatively, the air manifold may include a turbine 147 arranged along the inlet air flow path (e.g., between the external inlet orifice and the cabin interior), which functions to convert energy of the inlet flow into usable energy. Additionally, the turbine may function to reduce the temperature of the inlet flow. Additionally or alternatively, the turbine may reduce the pressure of the inlet flow and / or balance the pressure of the inlet flow with ambient pressure. In a specific example, at cruising speed (e.g., 200 mph), the air in the inlet flow may be 3-5° C. above ambient temperature as a result of the dynamic pressure at the inlet orifice. Additionally or alternatively, in some cases, the ambient air may be 20° C. or more above the desired cabin temperature (e.g., for a cabin temperature set point of 20° C.). By using the turbine to capture energy from the inlet flow, the temperature of the inlet air is reduced, which may therefore reduce the required cooling of the onboard thermal management subsystem (in cooling mode). Additionally or alternatively, the captured energy can be used to power a fan along the exhaust path that pressurizes the flow through the outlet nozzle 148 and reduces drag on the vehicle.

[0090] The turbine may include airfoil fins (blades), which are mechanically coupled (e.g., radially) to the central shaft. Flow across the airfoil fins induces mechanical rotation of the shaft. The turbine is preferably sized to extract sufficient power from the inlet flow to power an outlet fan or other powered components during vehicle operation (e.g., flight), but may alternatively be sized to extract more or less power. In a first variant, a generator is connected to the shaft and converts the rotational energy into electrical energy, which may be used to power an electric fan or stored in a battery for future use. An example is shown in FIG. 6. In a second variant, the central shaft is mechanically coupled to the outlet fan by the central shaft. An example is shown in FIG. 5. However, the turbine may be suitably implemented otherwise.

[0091] However, the air manifold may include any other suitable components.

[0092] The on-board thermal management subsystem may include one or more fluid loops that function to transfer thermal energy and / or establish thermal communication between components of the on-board thermal management system. The fluid loops may additionally function to enclose / contain a working fluid, which stores thermal energy and / or increases the thermal capacity of the on-board thermal management subsystem. The fluid loops may additionally function to establish fluid communication between two or more thermal interfaces (e.g., heat exchangers). The fluid loops may be single-mode and / or multi-mode, configurable between a heating mode (e.g., an example is shown in FIG. 7), a cooling mode (an example is shown in FIG. 8), and / or a fluid circulation mode. In one example, the battery loop (an example is shown in FIG. 9) operates uniformly, continuously, and / or exclusively in a fluid circulation mode. In a second example, the cabin loop may be configurable between a heating mode and a cooling mode.

[0093] The set of fluid loops preferably includes a cabin loop, and may optionally include a battery loop, a refrigeration loop, and / or any other suitable fluid loop.

[0094] The cabin loop preferably thermally and / or fluidly connects a first heat exchanger (e.g., a battery heat exchanger) in thermal communication with the battery pack to a second heat exchanger (e.g., a cabin heat exchanger) in fluid and / or thermal communication with the cabin air. An example is shown in FIG.

[0095] The battery loop preferably thermally and / or fluidly connects the battery pack (and / or a heat exchanger in conductive thermal contact with the battery pack) to the cabin loop. In a specific embodiment, the battery loop can be a circulation subsystem, as described in U.S. Application No. 16 / 857,003, filed April 23, 2020, which is incorporated by reference in its entirety. However, other battery loops can be used.

[0096] The refrigeration loop is preferably a refrigeration system and / or a heat pump (e.g., a reversible heat pump). The refrigeration loop may include a refrigerant manifold, an evaporator 135, a condenser 134, and / or other components. The thermal capacity of the refrigeration loop (and / or refrigeration system) may be under-specified (e.g., less than an estimated excess heat), specified for only the battery or only the cabin, over-specified, or otherwise configured with respect to the battery and cabin, or a combination of the battery or the cabin. Alternatively, the on-board thermal management subsystem may exclude the refrigeration loop, include only a refrigeration loop for the cabin, include only a refrigeration loop for the battery, or be otherwise configured.

[0097] However, the on-board thermal management subsystem may include any other suitable fluid loop.

[0098] The different fluid loops are preferably fluidly isolated from one another, but may alternatively be fluidly connected to one another (e.g., the different fluid loops are subloops of a larger loop), selectively fluidly connected to one another (e.g., via one or more valves), or otherwise fluidly associated. The different fluid loops are preferably thermally connected to one another (e.g., via a heat exchanger, heat pump, thermal interface, thermally conductive manifold side, etc.), but may alternatively be thermally isolated from one another, selectively thermally connected to one another (e.g., via one or more valves, heat exchangers, etc.), or otherwise thermally associated.

[0099] Each fluid loop may include a working fluid 152, one or more heat exchangers 130 (e.g., one side of a fluid-fluid heat exchanger, an internal volume therein, such as the fluid interior of a gas-fluid heat exchanger), a pump 122, a fluid manifold 124, and a reservoir 150. The fluid loops may optionally include a heater, a set of valves 126 (e.g., a four-way valve), and a deionization filter. However, the fluid loops may include any other suitable components.

[0100] The fluid loop can include a working fluid, which serves as a medium for exchanging heat between the heat exchangers (and thermal interfaces therein) of the fluid loop. For example, the working fluid can be water, a water / glycol mixture (e.g., 50 / 50, 70 / 30, 80 / 20, etc.), a refrigerant (e.g., R134a), oil, air, a fluid coolant, mineral oil, any other suitable gas or gas mixture, and / or any other suitable fluid. Alternatively, the working fluid can be a non-hazardous, natural, or biodegradable fluid to minimize the environmental impact of a leak or spill. Alternatively, the working fluid can be non-conductive (e.g., mineral oil), which can eliminate the possibility of shorting out electronics and / or allow for flood cooling of the battery cells 114 (e.g., in a fully flooded configuration).

[0101] Alternatively, the two or more fluid loops of the on-board thermal management subsystem may contain different types and / or distinct volumes of working fluids that are fluidly isolated from one another. In a first example, the battery loop 123 may contain a first working fluid that is replenished, replaced, and / or recirculated during preconditioning. In a second example, the cabin loop 123 may contain a second working fluid that is fluidly isolated from the first working fluid within the battery loop. The second working fluid may be of the same type (e.g., a water / glycol mixture) that remains fluidly isolated during one or more operating modes. In a third example, the refrigeration loop 125 contains a third working fluid, such as a refrigerant, that is fluidly isolated from the first working fluid and the second working fluid.

[0102] However, the fluid loop may include any other suitable working fluid.

[0103] The fluid loop may include one or more heat exchangers, which function to transfer thermal energy between various media of the system and / or to establish a thermal interface between two media. The heat exchangers may be any suitable type of heat exchanger. The heat exchangers are preferably active (e.g., transfer thermal energy through forced convection, heat pumping, etc.), but may additionally or alternatively be passive (e.g., conductive elements).

[0104] In a first variation, the heat exchanger can be a solid-fluid type heat exchanger 133, which transfers thermal energy between a solid body and a fluid (e.g., working fluid, air, etc.), and can be a chill plate, a hot plate, a cold plate, a heat sink, and / or any other suitable solid-fluid heat exchanger. In a specific embodiment, a fluid loop (e.g., a battery loop) includes a solid-fluid heat exchanger that is thermally connected to one or more cells of a battery pack and establishes a thermal interface between the working fluid in the fluid loop. The working fluid is fluidly connected to a fluid interior of the heat exchanger, such as one that extends between the inlet and outlet ports of the heat exchanger. The solid-fluid heat exchanger can optionally include a thermal interface material (TIM), which establishes thermal contact between the solid body (e.g., a heat-generating component) and the remainder of the heat exchanger at the thermal interface. The TIM can include thermal grease, thermal adhesive, thermal gap filler, thermally conductive pad (e.g., silicone sheet), thermal tape, phase change material, metallic TIM, compressive / elastomeric TIM, and / or any other suitable TIM. In a first embodiment, the TIM can be a thermally conductive elastomer sandwiched between the cold plate and the battery pack. However, other suitable solid-fluid heat exchangers can also be used.

[0105] In a second variant, the heat exchanger can be a fluid-fluid type heat exchanger, which functions to establish thermal communication between two fluids. The fluid-fluid type heat exchanger can include a gas (air)-liquid type heat exchanger, which functions to establish thermal communication between the fluid loop and / or the working fluid therein and a gas (such as cabin air). The gas-liquid type heat exchanger can include a radiator, an oil cooler, and / or any other suitable type of heat exchanger. In a first example, the gas-liquid heat exchanger (e.g., cabin heat exchanger) is in the fluid loop and encloses a portion of the working fluid within the interior, such as between an inlet port and an outlet port.

[0106] In a first embodiment, a gas-liquid type heat exchanger is arranged within the interior of an air manifold (e.g., in a cross-flow arrangement, along a recirculating flow path, etc.), and cabin air (and / or exterior air passed through the air manifold inlet) is blown across the exterior surface (e.g., fins, parallel plates, etc.) of the heat exchanger. The material body of the heat exchanger establishes a thermal interface between the air passing across the exterior of the heat exchanger and the fluid interior. Fluid communication of the working fluid with the heat exchanger allows for convective heat transfer therebetween. Fluid communication of the cabin air and the exterior of the heat exchanger allows for convective heat transfer therebetween. The structure of the heat exchanger can conductively transfer thermal energy between the interior and exterior. A combination of exterior convection, conduction, and interior convection establishes a thermal interface between the working fluid and the cabin air.

[0107] However, other suitable gas-to-liquid type heat exchangers may be used in any other suitable location.

[0108] The fluid-fluid type heat exchanger may include a liquid-liquid type heat exchanger (and / or a liquid-refrigerant heat exchanger), which establishes thermal communication between two fluid loops. Alternatively, a liquid-liquid (or liquid-refrigerant) type heat exchanger may function to define a thermal interface between two fluid loops. The liquid-liquid (or liquid-refrigerant) type heat exchanger may be a parallel flow heat exchanger, a counterflow heat exchanger, a cross-flow heat exchanger, a shell and tube heat exchanger, a plate heat exchanger, a plate-fin heat exchanger, a plate-shell heat exchanger, and / or any other suitable heat exchanger. A liquid-liquid (or liquid-refrigerant) type heat exchanger includes a first interior (e.g., a first interior extending between a first inlet port and a first outlet port of the heat exchanger) that surrounds a first working fluid in a first fluid loop, and a second interior (e.g., a second interior extending between a second inlet port and a second outlet port of the heat exchanger) that surrounds a second working fluid in a second loop. The fluid communication of each working fluid and the heat exchanger allows for convective heat transfer therebetween. The structure of the heat exchanger can conductively transfer thermal energy between the first interior and the second interior. The combination of convection with the first working fluid, conduction through the structure of the heat exchanger, and convection with the second working fluid establishes a thermal interface between the first working fluid and the second working fluid. Similarly, this thermal interface thermally connects the first loop and the second loop in the heat exchanger. A liquid-liquid (or liquid-refrigerant) type heat exchanger may be considered to be "in" a respective fluid loop that defines a fluid path extending through the interior of the heat exchanger. Alternatively, a liquid-liquid (or liquid-refrigerant) type heat exchanger may be considered to be "in" a respective fluid loop that is associated with a working fluid in fluid communication with the interior of the heat exchanger.

[0109] In a specific embodiment, a liquid-to-liquid type heat exchanger (eg, a battery heat exchanger) can connect the battery loop (in thermal communication with the battery pack) and the cabin loop.

[0110] In a second specific example, a liquid-refrigerant type heat exchanger can be connected to the refrigeration system to the cabin loop. The liquid-refrigerant type heat exchanger can operate as the evaporator 134 and / or condenser 135 of the refrigeration system. Note that in various operating modes, the refrigerant can be a liquid, a gas, and / or a liquid-gas mixture.

[0111] However, other suitable liquid-liquid (or liquid-refrigerant) type heat exchangers may be used in any other suitable location.

[0112] The heat exchanger may thermally and / or fluidly connect the battery pack to the cabin loop, the cabin loop to the battery loop, the cabin loop to the cabin air, the refrigerant loop to the cabin loop (e.g., first and / or second sub-loops therein), and / or otherwise suitably connect fluid loops within the onboard thermal management subsystem, however, the heat exchanger may be otherwise suitably arranged within the fluid loops and / or fluidly connected to the fluid loops in any suitable manner.

[0113] The heat exchangers may be located in the wings of the aircraft, mounted in the battery packs and / or battery pack housings, in the air manifolds and / or along the air flow paths of the air manifolds, and / or otherwise suitably distributed about the aircraft, however, the heat exchangers may be otherwise distributed in any suitable location about the vehicle.

[0114] The system may include any suitable number of heat exchangers. Preferably, each fluid loop includes (e.g., thermally and / or fluidly connected to) at least two heat exchangers. The battery loop preferably includes at least one solid-fluid type heat exchanger per battery pack and one liquid-liquid type heat exchanger connecting the battery loop to the cabin loop. In a first example, where the aircraft includes four battery packs, the battery loop includes five heat exchangers. However, the battery loop may include any suitable number of heat exchangers. In a second example, the cabin loop may include two heat exchangers, namely, a battery heat exchanger 131 and a cabin heat exchanger 132, which establish thermal communication between the cabin loop and the battery packs (and / or the battery loop). In a third example, the cabin loop may include four heat exchangers, namely, a battery heat exchanger 131, a cabin heat exchanger 132, an evaporator 135, and a condenser 134. The on-board thermal management subsystem may include two, three, four, five, six, eight, and / or any other suitable number of heat exchangers, however, there may be any other suitable number of heat exchangers.

[0115] The heat exchanger may include ports that fluidly connect the heat exchanger to the fluid manifolds of the fluid loops. According to the direction of the working fluid flowing through the fluid loops (e.g., established based on the orientation and / or operation of the pump), the set of ports may include at least one inlet port and at least one outlet port for each fluid loop, with the interior of the heat exchanger fluidly connecting the inlet port to the outlet port associated with the common loop, and the working fluid flow paths in the fluid loops extending through the interior from the inlet port to the outlet port. Each heat exchanger may include a single fluid flow path for each working fluid, two fluid flow paths associated with different working fluids, multiple fluid flow paths associated with a single working fluid, and / or any suitable number of fluid paths extending therethrough. However, the heat exchanger may include any other suitable ports.

[0116] The heat exchanger of the on-board thermal management subsystem may include a battery heat exchanger, which functions to thermally connect the battery (and / or battery loop) and the cabin loop. In a first variant in which the on-board thermal management subsystem includes a battery loop and a cabin loop, the battery heat exchanger may be a liquid-liquid type heat exchanger that establishes thermal communication between the battery loop and the cabin loop, the battery heat exchanger being in both the battery loop and the cabin loop. In a second variant, the battery heat exchanger is a solid-liquid type heat exchanger arranged in the cabin loop in fluid communication with the working fluid in the cabin loop, the battery heat exchanger being in conductive thermal contact between one or more battery cells of the battery pack. In this variant, the battery heat exchanger establishes thermal contact along a thermal interface between the battery pack and the cabin loop. In a third alternative in which the working fluid in the cabin loop comprises a refrigerant, the battery heat exchanger comprises a condenser (e.g., the working fluid flows from an inlet at a first end, through an interior of the battery heat exchanger to an outlet at a second end of the battery heat exchanger in a cabin cooling mode) and / or an evaporator (e.g., the working fluid flows from a second end, through an interior of the battery heat exchanger to a first end of the battery heat exchanger in a cabin heating mode). However, the onboard thermal management subsystem may include any other suitable battery heat exchanger.

[0117] The heat exchanger of the onboard thermal management subsystem may include a cabin heat exchanger, which fluidly connects the onboard thermal management subsystem to the cabin air (within the cabin air manifold). The cabin heat exchanger is, in a blowing configuration, preferably a gas-to-liquid type heat exchanger arranged within the interior of the air manifold. Alternatively, the cabin heat exchanger may be arranged within the cabin interior (e.g., separate from the air manifold) and / or otherwise suitably arranged.

[0118] The heat exchanger of the on-board thermal management subsystem may optionally include an evaporator and a condenser (e.g., with terms assigned according to the phase of the refrigerant passing therethrough and / or the portion of the refrigeration cycle). In a first variant in which the set of fluid loops includes a cabin loop and a refrigeration loop, the evaporator and condenser are each liquid-refrigerant type heat exchangers that establish thermal communication between the cabin loop and the refrigeration loop. In a second variant, one of the evaporators / condensers is arranged in the battery loop and the other is located in the cabin loop. In a first embodiment of the second variant, in the heating mode, the evaporator is in the battery loop and the condenser is in the cabin loop. In a second embodiment of the second variant, in the cooling mode, the condenser is in the battery loop and the evaporator is in the cabin loop. In a third alternative, where the working fluid in the cabin loop is a refrigerant, the evaporator can be synonymous with the cabin heat exchanger (e.g., in cooling mode) and the condenser can be synonymous with the battery heat exchanger (e.g., in cooling mode).

[0119] However, the system may include any other suitable heat exchanger.

[0120] The fluid loop may include a fluid manifold, which serves to contain the working fluid and fluidly connect the rest of the components of the fluid envelope. The fluid manifold may fluidly connect and / or terminate at a pump in the fluid loop, a heat exchanger in the fluid loop, a fluid coupling 174, a reservoir, and / or any other suitable components connected in any combination of series and / or parallel. The fluid manifold may include piping, valves, and / or any other suitable fluid handling components. The fluid manifold may be tubing formed or otherwise defined by the cabin or aircraft housing. The fluid manifold may be thermally conductive, insulated, partially insulated (e.g., along a portion of the periphery), or insulated from the environment / ambient conditions. The fluid manifold may be constructed from any suitable material, such as metal, plastic, polymer, rigid material, non-rigid material, or any suitable combination thereof. The material of the fluid manifold is preferably selected to accommodate the properties / requirements of the working fluid (e.g., to avoid corrosion or other deleterious interactions, to avoid degradation in high and / or low temperature conditions, to meet the pressure requirements of the vehicle cabin thermal management system, to minimize head losses within the on-board thermal management subsystem, etc.), but may additionally or alternatively be selected using any suitable basis.

[0121] However, the fluid loop may include any other suitable fluid manifold.

[0122] The fluid loops of the on-board thermal management subsystem may include a pump (known as an on-board pump), which functions to circulate the working fluid through the fluid loop. The pump may be arranged in any suitable portion of the loop with any suitable relationship to other components connected by the fluid manifold. The operation and / or pumping action of the pump preferably dictates the direction of the working fluid flow and / or the working fluid flow path through the fluid loop. In alternative embodiments, the pump and / or a reversing valve may modify the direction of the working fluid flow through one or more portions of the loop. The fluid loops may include any suitable number of pumps. Preferably, each fluid loop includes at least one pump, however, the fluid loops may include multiple pumps arranged in series and / or parallel. In a first alternative embodiment, in one or more operating modes (e.g., cabin heating mode), two pumps may be redundantly arranged in series, each configured to transport the working fluid through the fluid loop independently. In a second alternative, a four-way valve in the cabin loop may selectively fluidly and / or thermally isolate a first portion of the working fluid from a second portion of the working fluid (e.g., in a cabin cooling mode) and subdivide the cabin loop into subloops 127 including a first subloop (first portion of the working fluid in the first subloop) and a second subloop (second portion of the working fluid in the second subloop). In the second alternative, a first pump transports the first portion of the working fluid through the first subloop and a second pump transports the second portion of the working fluid through the second subloop.

[0123] In an alternative embodiment including a battery loop, the battery loop preferably includes at least one on-board pump per battery pack, such that multiple battery packs are preferably associated with a corresponding multiple on-board pumps. However, the battery loop may include one pump per set of two battery packs and / or any other suitable number of on-board pumps. The pumps in the battery loop are preferably connected to a fluid manifold in parallel with the interface connections between the vehicle and the infrastructure equipment. More preferably, the on-board pumps in the battery loop may be arranged in close proximity to one or more battery packs, which may reduce the required mass / volume of working fluid and / or the fluid manifold components required to fluidly connect the pump to the battery pack. The on-board pumps in the battery loop may be integrated into the battery pack, separate from the battery pack, integrated into a reservoir, close to a hose fitting, and / or otherwise implemented. The on-board pump in the battery loop is preferably arranged between the battery packs where it serves (e.g., at a physical intermediate location along the fluid coolant circuit therebetween), but can alternatively be arranged to the side of the battery packs, in a separate vehicle component, or in any other suitable location. The on-board pump in the battery loop is preferably connected to the fluid manifold in parallel with the off-vehicle infrastructure equipment so that the on-board pump can be held idle during conditioning with the off-vehicle infrastructure equipment. In an embodiment, the on-board pump defines a pumping speed range that is matched to the volume of working fluid on-board the vehicle when the vehicle is removed from the infrastructure equipment, and when the vehicle is attached to the infrastructure equipment for conditioning, the on-board pump is not used in favor of the off-board pump (e.g., sized or otherwise configured for the larger pumping requirements of the combined system and working fluid volume). In a first alternative, the on-board pump of the battery loop is fluidly connected to and located between the two battery packs (e.g., flush with the battery packs, arranged within a protrusion on the side of the battery packs, etc.), thereby minimizing the length of tubing required.In a second alternative, the on-board pumps are located in the wings (e.g., two pumps, one in each wing), which can ensure that the fluid manifold does not encroach on the cabin space. However, the on-board pumps in the battery loop can be arranged differently.

[0124] The on-board pump can also function to circulate the working fluid through the fluid loop where it serves at a defined flow rate, which is determined by the on-board pump controller. The on-board pump is preferably sized (e.g., physically sized, sized according to maximum pumping speed and power requirements, etc.) according to the volume of the working fluid on-board the vehicle when the on-board thermal management subsystem is disconnected from the infrastructure equipment (e.g., smaller volume). For example, the on-board pump in the battery loop can be smaller, lighter, and / or less powerful than the on-board pump, since the on-board pump is preferably not used to circulate the working fluid during thermal preconditioning (e.g., when the circulation subsystem is connected to the infrastructure equipment and thus the heat exchanger). However, the on-board pump can additionally or alternatively be suitably sized differently.

[0125] Alternatively, the various pumps can operate at different flow rates during different operating modes. Preferably, the pump in the cabin loop circulates the working fluid at a first flow rate during cabin cooling mode and at a second flow rate during heating mode. In a first embodiment, the second flow rate can be 200% of the first flow rate, the same as the first flow rate, 50% of the first flow rate, 20% of the first flow rate, 10% of the first flow rate, 5% of the first flow rate, and / or any suitable range bounded by the aforementioned values. In a second embodiment, the cabin loop includes, in cabin cooling mode, a first sub-loop, a second sub-loop, a first pump in the first sub-loop, and a second pump in the second sub-loop. In a second embodiment, the flow rate through the first sub-loop and / or the second sub-loop exceeds the flow rate of the cabin loop in a cabin heating mode while the first and second pumps are arranged in series. Alternatively, reducing the flow rate of the cabin loop and / or the battery loop in a cabin heating mode can take advantage of transient thermal effects to increase the heating efficiency of the onboard thermal management subsystem. However, the flow rate of the pumps can be suitably controlled otherwise.

[0126] In that alternative variation, the pump can be a passive (e.g., unpowered) pump driven by a temperature difference resulting from waste heat (e.g., generated by a battery pack during discharge, by one or more electric motors during operation, etc.). The circulation subsystem can be arranged to create such a temperature difference to establish a convection loop of the working fluid through the envelope, e.g., the envelope can be arranged within a vehicle, rejecting heat to the environment at a first location and directing the working fluid around the closed thermally driven cycle (e.g., by gravity). However, the pump can also be suitably configured to passively circulate the working fluid otherwise in such a variation.

[0127] The pump can be any suitable type of pump, such as a submersible pump, a non-submersible pump, a positive displacement pump (e.g., rotary, reciprocating, linear), an impulse pump, a velocity pump, a centrifugal pump, an axial flow pump, a gear pump, a screw pump, a progressive cavity pump, a roots pump, a peristaltic pump, a plunger pump, a triplex plunger pump, a radial flow pump, a valveless pump, a helical pump, and / or any other suitable type of pump. The on-board pump can have any suitable maximum flow rate, which can be limited and / or otherwise defined based on the power supply, the physical limitations of the circulation subsystem, electronic controls. The maximum flow rate of the on-board pump can be <5L / min, 5L / min, 10L / min, 20L / min, 40L / min, 60L / min, 80L / min, 100L / min, >100L / min, any range defined by the aforementioned values, and / or any other suitable flow rate. The on-board pump can receive any suitable power supply. The input source can be AC ​​or DC, with any suitable supply voltage, such as 12VDC, 24VDC, 48VDC, 96VDC, 120VAC, 240VAC, the same voltage as the battery pack, and / or any other suitable supply voltage. The on-board pump power supply can have any suitable maximum sustained or peak power, such as <25W, 25W, 50W, 100W, 250W, 350W, 500W, 1kW, 2.5kW, 5kW, 10kW, >10kW, any suitable range defined by the aforementioned values, and / or any other suitable power.

[0128] The pump controller functions to operate the pump (e.g., an on-board pump) between various modes, including a fail-safe mode. In the fail-safe mode, the pump can operate at a high flow rate in response to detection of an off-nominal condition (e.g., a thermal event) to circulate working fluid through the battery pack, thereby mitigating an existing thermal event and / or preventing propagation of a thermal event across multiple cells in the battery pack. Entry into the fail-safe mode can be triggered by detection of a thermal event in one or more cells of the battery pack, loss of power to a redundant portion of the on-board pump controller (e.g., one of the two control modules), detection of a precursor condition of a thermal event, loss of communication, and / or any other suitable triggering event. The pump controller can adjust pump RPM, flow rate, pressure (e.g., pump head), power state (e.g., on / off), and / or any other suitable pump parameters.

[0129] The pump controller can be integrated into the battery electronics, integrated into the pump, or separate from the pump and battery electronics. The pump controller can be located proximate to the pump, proximate to the battery pack, proximate to a vehicle controller (e.g., a flight computer), between the battery pack and the pump, between two battery packs, and / or otherwise arranged.

[0130] The pump controller is preferably fault tolerant so that the on-board pump can effectively operate even if all or part of the battery pack fails (e.g., due to a thermal event, due to other trauma to the system, etc.) and stops delivering power. Fault tolerance can be achieved by powering the on-board pump controller and the on-board pump using redundant connectivity between the on-board pump controller and the on-board pump and a single battery pack; fault tolerance can additionally or alternatively be achieved from multiple battery packs using redundant connectivity to the on-board pump controller and the on-board pump.

[0131] In a specific example of the fault-tolerant configuration, the on-board pump can be powered by two different halves of the battery packs via parallel sets of three-phase windings (e.g., each electrically isolated subset of the same battery pack powers a different phase set of the pump). In a second specific example of the fault-tolerant configuration, the on-board pump is powered by a first battery pack and a second battery pack via distinctly different sets of three-phase windings.

[0132] In a fault-tolerant configuration, a fail-safe operating mode of the on-board pump can include operating the pump on one three-phase winding set if a thermal event occurs in one of the cells of the battery pack associated with the other of the two three-phase winding sets. The pump can enter the fail-safe mode (e.g., high flow rate) in response to various trigger events as described above, including loss of power to one of the parallel motor drive electronics subsystems (e.g., due to a thermal event that disrupts power delivery to one of the parallel motor drive electronics subsystems), receiving a fault trigger from the battery electronics (e.g., generated in response to a detected power surge or drop associated with a possible thermal event), and / or any other suitable trigger event.

[0133] However, the fluid loop may include any other suitable pump.

[0134] In a first variant of the cabin loop, in a cabin heating mode, a working fluid (e.g., a water / glycol mixture) in the cabin loop is driven by a pump through an inlet of a battery heat exchanger. The working fluid passes through the interior of the heat exchanger from inlet to outlet, convectively absorbing a first portion of thermal energy through the thermal interface of the battery heat exchanger. From the outlet, the working fluid is transported to the cabin heat exchanger inlet, which is fluidly coupled to the battery heat exchanger by the cabin loop fluid manifold, thereby transporting a first portion of heat to the cabin heat exchanger. The working fluid passes through the interior of the heat exchanger from the cabin heat exchanger inlet to outlet, transferring a first portion of thermal energy to the convective heating / cabin air through the thermal interface of the cabin heat exchanger. The working fluid then returns to the inlet of the battery heat exchanger, completing a full circuit of the cabin loop. In this configuration, the thermal interface of the battery heat exchanger has a temperature that exceeds the temperature of the working fluid, and the working fluid has a temperature that exceeds the temperature of the cabin air. In cabin cooling mode, the working fluid follows the same path, with the cabin air temperature exceeding the temperature of the working fluid, which exceeds the temperature of the battery pack (and / or working fluid in the battery loop). Thus, in cabin cooling mode, a second portion of the thermal energy is transferred from the cabin air through the thermal interface of the cabin heat exchanger and is convectively absorbed / stored by the working fluid. The heated working fluid is then transported through the fluid manifold from the outlet of the cabin heat exchanger to the inlet of the battery heat exchanger, thereby fluidically / thermally connecting the outlet of the cabin heat exchanger to the inlet of the battery heat exchanger. As the working fluid passes through the interior of the battery heat exchanger, a second portion of the thermal energy is transferred through the thermal interface of the battery heat exchanger and is stored within the thermal mass of the battery (and / or battery loop). Alternatively, the working fluid can exceed the ambient temperature and be cooled via a radiator or other heat sink arranged along the outlet path of the air manifold. A first example of the first variant is shown in FIG. 1. A second embodiment of the first variant is shown in FIG.

[0135] In a second alternative embodiment, the vehicle thermal management subsystem includes a refrigeration loop comprising a refrigerant in the refrigeration loop, a condenser, and an evaporator, the refrigeration loop configured to operate as a heat pump and transfer thermal energy from the evaporator to the condenser.

[0136] In a second alternative, the cabin loop optionally includes a four-way valve defining first, second, third, and fourth ports. The first port is fluidly connected to the battery heat exchanger inlet, with a flow path for the working fluid extending from the first port to the battery heat exchanger inlet. The second port is fluidly connected to the battery heat exchanger outlet, with a second flow path for the working fluid extending from the battery heat exchanger outlet to the second port. The third port is fluidly connected to the cabin heat exchanger inlet, with a third flow path for the working fluid extending from the third port to the battery heat exchanger inlet. The fourth port is fluidly connected to the cabin heat exchanger outlet, with a fourth flow path for the working fluid extending from the cabin heat exchanger outlet to the fourth port. In a cabin heating mode, the first port is fluidly connected to the fourth port, and the second port is fluidly connected to the third port. In the cabin heating mode, a first portion of the thermal energy can be transferred from the battery heat exchanger to the cabin heat exchanger in a manner similar to the first variant, since the battery heat exchanger is fluidly / thermally coupled to the cabin heat exchanger by the cabin loop. In addition, the heat pump can transfer a second portion of the thermal energy from the evaporator to the condenser, thereby transferring thermal energy from the working fluid in the interior of the evaporator to the working fluid in the interior of the condenser (e.g., including transient delays and / or losses). With an evaporator arranged in the fluid loop between the cabin heat exchanger outlet and the battery heat exchanger inlet (e.g., along the first or fourth flow path), and a condenser arranged in the fluid loop between the battery heat exchanger outlet and the cabin heat exchanger inlet (e.g., along the second or third flow path), the condenser can add a portion of the thermal energy to the working fluid before entering the cabin heat exchanger. Most preferably, the condenser is arranged in the second flow path (associated with the second port and the outlet of the battery heat exchanger) and the evaporator is arranged in the fourth flow path (associated with the fourth port and the outlet of the cabin heat exchanger). In this configuration, the net heating power transferred from the cabin loop to the cabin air (at the cabin heat exchanger) can be a third portion of energy, which is equal to the sum of the first portion of energy and the second portion of energy (e.g., neglecting losses, transients, etc.).A second alternative cabin heating mode embodiment is shown in Figures 7 and 22B.

[0137] In a second alternative cooling mode, the four-way valve fluidly connects the first flow path to the second flow path and the third flow path to the fourth flow path. In this configuration, the first and second flow paths define a first sub-loop of the cabin loop, the third and fourth flow paths define a second sub-loop of the cabin loop, and the battery heat exchanger and the cabin heat exchanger are arranged within the first and second sub-loops, respectively. The first sub-loop (and the battery heat exchanger) can be partially or completely fluidly isolated from the second sub-loop (and the cabin heat exchanger), with the first sub-loop containing a first portion of the working fluid and the second sub-loop containing a second portion of the working fluid. In this condition, the battery heat exchanger is thermally decoupled from the cabin heat exchanger. The condenser (and pump) is arranged in a first sub-loop and the evaporator (and pump) is arranged in a second sub-loop. Operating a heat pump between the evaporator and the condenser can drive the transfer of a portion of thermal energy from the cabin air to the battery according to the following thermal circuit: a portion of thermal energy is transferred from the cabin air to the cabin heat exchanger, a second portion of the working fluid transfers a portion of thermal energy from the cabin heat exchanger through the second sub-loop to the evaporator, the refrigeration loop (heat pump) transfers a portion of thermal energy from the evaporator to the condenser, a first portion of the working fluid transfers a portion of thermal energy to the battery heat exchanger, which transfers a portion of thermal energy to the battery (e.g., a portion of thermal energy is absorbed / stored for the duration of the flight, etc.). An example of the second variant in cabin cooling mode is shown in Figures 8 and 22A.

[0138] However, in a second alternative, the condenser and evaporator may be suitably arranged and / or employed differently within the cabin loop.

[0139] In an alternative embodiment of the system including a battery loop, the collective thermal mass of the battery and the battery loop can absorb a second portion of the thermal energy as described in the first alternative embodiment. In such a case, the battery loop contains a second working fluid, which is thermally coupled to the first working fluid by the battery heat exchanger. In a cabin heating mode, a second pump in the battery loop drives the flow of the second working fluid through a fluid interior (e.g., cold plate / hot plate) of a heat exchanger that is thermally connected to the battery pack. A first portion of the thermal energy is transferred from the battery to the second working fluid at the thermal interface of the heat exchanger. The working fluid transfers the first portion of the thermal energy from the heat exchanger to a second inlet of the battery heat exchanger, which is fluidly connected to the heat exchanger via a fluid manifold of the battery loop. The second working fluid passes through the second interior of the battery heat exchanger from the second inlet to the second outlet of the battery heat exchanger. The first portion of the thermal energy is then transferred from the second working fluid to the first working fluid through the thermal interface of the battery heat exchanger, thereby establishing fluid communication between the first and second loops. An example is shown in FIG. 21 and FIG. 22B. In cabin cooling mode, the second portion of the thermal energy is received by the second working fluid at the battery heat exchanger. An example is shown in FIG. 22A. In an alternative embodiment of the system that preconditions the second working fluid via the on-board infrastructure, conditions may exist where the battery temperature and the temperature of the first working fluid both exceed the temperature of the second working fluid (as may occur frequently given the transient nature of thermal fluid systems). In such a case, there may be a net thermal flow from both the heat exchanger and the battery heat exchanger into the second working fluid. In the first example, the second portion of the thermal energy may be stored by the thermal mass of the collective system of the battery loop (and the working fluid therein) and the battery pack.In a second embodiment, the second portion of the thermal energy can reduce the effective heat capacity of the second working fluid (e.g., defined by the specific heat of the second working fluid multiplied by the mass of the second working fluid and the temperature delta between the second working fluid and the battery pack), ultimately resulting in a net heat gain (e.g., equal to the second portion of the thermal energy) for the battery. Thus, the second working fluid can transfer the second portion of the thermal energy to the battery pack with a time effect and / or a reduced thermal capacity. However, the second portion of the thermal energy can be suitably transferred to the battery pack otherwise in cabin cooling mode.

[0140] However, the arrangement of components within the fluid manifold and fluid loops may define any suitable heat and / or fluid paths through each of the fluid loops, and / or the cabin loops may be configured to transfer thermal energy packets (e.g., a portion of the thermal energy) between the cabin heat exchanger and the battery heat exchanger in any suitable manner.

[0141] The fluid loop may optionally include a reservoir, which serves to store the working fluid. The reservoir may be constructed from any suitable material, such as metal, plastic, composite, and / or any other suitable material. The material choice for the reservoir may allow for various advantages. The material (e.g., aluminum, metal, etc.) may be selected to allow passive heat dissipation through the vehicle frame / body to the surrounding environment. The material may be selected to allow arbitrary arrangement of the reservoir, where plastic (e.g., blow molded, injection molded) may offer a high degree of geometric variance at low cost, while composites may minimize weight and / or serve as a structural element of the vehicle.

[0142] In addition, the reservoir can function as a thermal reservoir (adding thermal mass to the system). The volume for the thermal reservoir (and / or associated mass of working fluid) can be selected based on a range of trade-offs between heat capacity (e.g., due to the specific heat of the working fluid contained in the reservoir) and the added mass of fluid. Alternatively, the pump can selectively increase and / or decrease the mass of working fluid contained in the reservoir before commencing a voyage based on the temperature set point prior to takeoff and / or other voyage parameters to ensure optimal efficiency and / or range for different voyages.

[0143] However, the fluid loop may include any other suitable reservoir.

[0144] The fluid loop may optionally include a heater, which functions to add thermal energy to the fluid loop. The heater may receive power from any suitable power source. The heater power source may include an electrical connection to a battery pack, a gas reservoir, and / or any other suitable power source. The heater may be any suitable type of heater, such as a resistive heater (e.g., a positive temperature coefficient / PTC heater), an inductive heater, a gas heater, and / or any other suitable type of heater. The heater may be located in any suitable fluid loop, such as a battery loop (e.g., may enable battery warming to avoid degradation during cold starts) and / or a cabin loop. The heater in the cabin loop may be located at an inlet port of the cabin heat exchanger, in a sub-loop that includes the battery heat exchanger, in a sub-loop that includes the cabin heat exchanger, thermally connected to and / or integrated with the battery heat exchanger, thermally connected to and / or integrated with the cabin heat exchanger, and / or otherwise suitably arranged.

[0145] The fluid loop may optionally include a cooler, which functions to remove thermal energy from the fluid loop. The cooler may be a heat pump (e.g., pumping heat away from the working fluid of the fluid loop), a cold heat sink element (e.g., ice, nitrogen, etc.), a phase change material (e.g., paraffin), and / or any other suitable element.

[0146] However, the fluid loop may alternatively add supplemental thermal energy to the fluid loop in any suitable manner, or exclude the heater.

[0147] In another embodiment, where the working fluid of the fluid loop is a refrigerant (e.g., a refrigerant loop), the fluid loop may include a compressor 192, a thermal expansion valve (TXV) 194, and optionally a dryer and / or a refrigerant filter 196. Such a fluid loop may thus be employed in an on-board refrigeration system and / or a heat pump. In some cases, it may be further advantageous to employ a reversing valve (or a four-way valve) and employ the refrigerant loop in a reversible heat pump configuration.

[0148] The fluid loop may optionally include a hose fitting, which functions to fluidly connect the working fluid in the on-board fluid loop to off-vehicle infrastructure (e.g., an on-board cooling system). Preferably, the hose fitting establishes a dry connection (minimal leakage from connection / disconnection), but may alternatively establish a wet connection and / or any other suitable fluid connection. The fluid fitting may be threaded or non-threaded, with or without a male-female transition, tapered or non-tapered, may optionally include a gasket, may optionally include a spring-loaded valve (e.g., dry connection), and / or may have any other suitable features. The hose fitting may include a cam lock, quick connect, quick disconnect, flange fitting, hose link, fast fitting, Storz fitting, tri-clamp connection, lever lock, and / or any other suitable hose fitting type. The hose fittings can be any suitable material, such as brass, stainless steel, aluminum, plastic, and / or any other material with any suitable material finish (e.g., corrosion resistant, etc.). The hose fittings can include a vehicle side (integrated with the vehicle and connected to the circulation subsystem) and an outside side (e.g., mechanically connected to an infrastructure facility). In a first variant, the outside side of the hose fitting 176 can be integrated with the charging connector 172 (e.g., part of the charging handle, as shown in the example in FIG. 16). In a first example, the fluid connection and the electrical connection are established simultaneously. In a second example, the fluid connection can be engaged / disengaged separately from the electrical connection. In a second variant, the vehicle side of the hose fitting is separate from the electrical connector. In a third variant, the system includes a set of inlet hose fittings and a set of outlet hose fittings to enable back-and-forth circulation of the working fluid through the fluid loop. The system may include any suitable number of hose fittings, such as zero, one, two, three, four, more than four, and / or a suitable number of hose fittings per aircraft, pump, battery pack, reservoir, charging station, electrical connector, charger, fluid loop.

[0149] The off-vehicle infrastructure subsystem may optionally include a charging station, which functions to supply electrical energy to the battery pack. The charging station may be integrated with the on-board cooling system or may be separate. The electrical connector 172 (e.g., charger) and hose fitting 176 may be integrated into a single device (e.g., charging handle) or may be separate devices. There may be any suitable number of charging stations, such as one or more per aircraft, battery pack, pump, hose fitting, or there may be multiple aircraft, battery packs, pumps, and / or hose fittings associated with a single charging station. In a first alternative, the system includes a single charger (e.g., with + / - sides) and a single (on-board side) hose fitting (e.g., with separate inlet and outlet tubes), which may connect to the rear of the vehicle, the front of the vehicle, the side of the vehicle, the wing of the vehicle, and / or other suitable end points. In a second variant, the system includes two (external) hose fittings (e.g., with separate inlet and outlet pipes) that can connect to the front / rear of the vehicle, the left / right side of the vehicle, the left / right wings of the vehicle, and / or other suitable vehicle end points.

[0150] The off-vehicle infrastructure subsystem may preferably include an on-board cooling system that functions to exchange heat between the working fluid and the external environment, to remove heat from the aircraft (e.g., outside the aircraft), to remove heat from a fluid loop (e.g., a battery loop), and / or to otherwise manage heat. In a first variant, the on-board heat exchanger directly exchanges heat from the working fluid to the ambient air (e.g., by forced convection). In a second variant, the on-board heat exchanger indirectly exchanges heat to the external environment by thermally connecting the working fluid in one or more of the fluid loops to a sub-ambient cooling system (e.g., a refrigeration cycle). In a third variant, the on-board cooling system replaces a first volume of the working fluid in one or more of the fluid loops with a second pre-cooled volume of the same working fluid. The first volume of the working fluid can then be cooled and / or reused for a subsequent vehicle preconditioning / charging cycle. The on-board heat exchanger can cool and / or heat the working fluid depending on the desired temperature set point of the battery pack. Since the on-board heat exchanger is preferably a component of infrastructure equipment, the type and configuration of the heat exchanger is preferably not constrained by the available space and / or mass budget associated with the vehicle. The on-board heat exchanger is preferably an active heat exchanger (e.g., the working fluid is actively flowed through the structure to increase heat transfer from the working fluid to an external environment such as air, an external fluid such as air is actively flowed to increase heat transfer to or from the working fluid, etc.), but can additionally or alternatively be a passive heat exchanger (e.g., a heat sink) that transfers heat to or from the working fluid to an external fluid medium (e.g., air). The on-board heat exchanger can include a condenser, an evaporator, a radiator, a refrigeration system, a cooling system, and / or any other suitable components. An example is shown in FIG. 21. A second example is shown in FIGS. 22A-22B.

[0151] The system may optionally include an authorization mechanism, which functions to ensure that an authorized cooling and / or charging system may charge / precondition the vehicle. In a first variant, the authorization system is mechanical. In a first embodiment of the first variant, a dedicated key unlocks the fluid coupling. In a second embodiment of the first variant, the fluid coupling has a dedicated interface. In a second variant, the authorization system is digital. In a first embodiment of the second variant, the on-board fluid coupling head or the on-board charging and / or cooling equipment transmits its identifier to a controller (e.g., an on-board controller), which matches the on-board charging / cooling system (e.g., with an on-board database, with a central management system, with a dedicated cloud system, etc.), and the controller initiates cooling / charging in response to the match (e.g., by starting the pump, unlocking the fluid coupling, etc.). In a second embodiment, the on-board charging and / or cooling system matches the aircraft in the same or similar manner as in the first embodiment.

[0152] The system may include a controller. The controller may be distributed across multiple nodes (e.g., computing nodes on-board the vehicle and nodes coupled to infrastructure equipment) or centralized at a single point (e.g., a centralized controller communicatively coupled to controllable components of the system, commanding a set temperature, performing portions of method 200, etc.). The controller functions to execute command instructions and control portions of the vehicle cabin thermal management system based on input data. In an embodiment, the controller may perform or implement all or a portion of method 200. However, the controller may additionally or alternatively perform or implement any suitable functionality of the system components as described herein or otherwise suitably defined.

[0153] The system of the preferred embodiment and its variations can be embodied and / or implemented, at least in part, as a machine configured to receive a computer-readable medium storing computer-readable instructions. The instructions are preferably executed by computer-executable components that are preferably integrated with and / or part of the system. The computer-readable medium can be stored on any suitable computer-readable medium, such as RAM, ROM, flash memory, EEPROM, optical devices (CD or DVD), hard drives, floppy drives, or any suitable device. The computer-executable components are preferably general or application-specific processors, although any suitable dedicated hardware or combination hardware / firmware device can alternatively or additionally execute the instructions. 4. Method

[0154] Method 200 includes determining a temperature set point for the battery pack S100, regulating the battery pack temperature to the temperature set point S150, and regulating the cabin air temperature using the cabin thermal management system S300. The method may additionally or alternatively include determining a temperature of the battery pack S200 and redistributing heat within the battery pack based on the temperature of the battery pack S250. Method 200 may additionally or alternatively include any other suitable processes.

[0155] Method 200 functions to prepare a vehicle's cabin thermal management subsystem for operation and to facilitate cabin temperature regulation during vehicle operation, however, method 200 may additionally or alternatively have any other suitable functionality.

[0156] Block S100 includes determining a temperature set point for the battery pack. Block S100 functions to determine a target temperature to which the battery pack should be conditioned. Block S100 is preferably performed prior to vehicle departure from the infrastructure facility such that active conditioning components of the off-vehicle infrastructure facility can be used to condition the battery pack (e.g., according to one or more variations of block S150), although block S100 can additionally or alternatively be performed at any other suitable time. Block S100 is preferably performed automatically by a controller substantially similar to the controller of system 100, but can otherwise be suitably performed by any suitable component of a suitable system and / or entity associated with such a system (e.g., a human operator).

[0157] The temperature set point is preferably a take-off temperature set point, but can additionally or alternatively be an operating set point or any other suitable set point.

[0158] Block S100 is preferably performed based on a navigation profile of the vehicle. The navigation profile may include duration, navigation range, vehicle weight, time spent in various operating modes (e.g., hovering, forward / cruise, transition, takeoff, landing, etc.), ambient temperature (e.g., location along the route), battery parameters (e.g., age, capacity, cell type / model, current temperature, current SoC, SoP, SoH, etc.), vehicle weight, cargo weight, weight distribution, and / or any other suitable parameters. The battery parameters may be determined for individual cells, may be generic for cells with similar parameters, may be determined for a battery pack, may be generic for battery packs with similar parameters, or may be otherwise determined. In an embodiment where the vehicle is an aircraft, the navigation profile may include a flight plan (e.g., for one or more flights or legs of a flight) and / or any other flight data (e.g., weather data, air traffic data, etc.). The navigation profile may be received from a user, a user device, an on-board controller, a remote system, and / or other suitable endpoint and may include any other suitable set of parameters.

[0159] Block S100 may include determining an expected power consumption for the navigation (e.g., flight). The expected power consumption may be determined based on a navigation profile, a power consumption model, and / or other information. In a first variant, the expected power consumption may be determined based on a physical vehicle model, which may be determined theoretically or experimentally based on test data or historical navigation data (e.g., for a vehicle, for a fleet of vehicles). In a second variant, the expected power consumption may be selected from a lookup table / chart for the navigation profile and / or the physical vehicle model. In a third variant, the expected power consumption may be determined based on a machine learning model trained to output the expected power consumption. However, the expected power consumption for the navigation may also be determined differently.

[0160] Block S100 may include determining an expected heat production during the journey (e.g., flight) based on the battery model (an example is shown in FIG. 19). The expected heat production may be a heat production rate, heat generated between flight locations, a rate of heat production, and / or other heat production parameters. The expected heat production may be selected (e.g., from a look-up table), calculated (e.g., from an equation, by a battery model, etc.), or otherwise determined. The battery model may be generated based on test data (e.g., experimental testing of battery cells, of a battery pack), historical flight data for a given battery pack, a pre-defined model (e.g., received from a manufacturer or battery characterization entity, etc.), or otherwise generated. The battery model may be selected for use based on a battery cell type (e.g., class, manufacturer, model, etc.), pre-determined, or otherwise determined. The battery model can determine the expected heat production based on a starting battery pack temperature (e.g., averaged across all cells, measured at a single temperature sensor for the pack, temperature of the working fluid, etc.), an estimated state of charge (e.g., at takeoff), an estimated state of health (SoH) for the battery pack or each battery cell, an expected power consumption for the flight (e.g., total power consumption, as a time series, power consumption rate, etc.) (e.g., determined from an aircraft model or simulation, lookup table, etc.), battery specifications, and / or any other suitable parameters. In a first alternative, the expected heat production is selected from a lookup table / chart for given input parameters. In a second alternative, the expected heat production is determined based on a machine learning model trained to output the expected power consumption. However, the expected heat production during the flight (e.g., flight) can be determined differently.

[0161] Block S100 may include determining an expected temperature rise of the battery pack based on the expected heat production. The temperature rise may be an absolute temperature increase over the entire journey (e.g., flight), a temperature increase per mission segment (e.g., each leg of the flight), a rate of increase, or another parameter. The expected temperature rise may be determined based on the thermal mass (e.g., specific heat) of the battery pack, the specific heat of the working fluid (e.g., for a known volume and / or temperature of the working fluid), and / or the expected heat loss during the journey (e.g., expected heat dissipation to the environment, to the rest of the vehicle, to the cabin, from heat sources / sinks, etc.). The thermal mass of the battery pack may be determined experimentally by testing, theoretically modeled (e.g., calculated), determined based on historical temperature changes during charging and / or discharging, retrieved from a database, and / or otherwise determined. The thermal mass of the battery pack can be the absolute thermal mass of the battery pack, the available thermal mass of the battery pack (e.g., the amount of heat the battery pack can absorb before reaching a maximum battery temperature, discussed below, given the current battery pack temperature and / or the estimated battery pack temperature at takeoff), and / or other thermal parameters.

[0162] Based on the expected thermal rise, block S100 can optionally include determining an expected temperature difference between the battery cells and the working fluid, which can include assuming a fixed offset (e.g., same temperature, 2° C. difference, etc.), dynamically modeling temperature transients based on material properties and flow rates, using historical / test data, and / or otherwise determining the expected temperature difference. However, the expected temperature rise of the battery pack and / or cells can also be determined otherwise.

[0163] Block S100 may include offsetting the expected temperature rise from the battery temperature requirement to determine the temperature set point. The battery temperature requirement may be a maximum battery (pack or cell) temperature >65°C, 65°C, 60°C, 55°C, 50°C, 45°C, 40°C, <45°C, any range bounded by the aforementioned values, and / or any other suitable temperature. The battery temperature requirement may be determined based on test data, battery specifications, battery efficiency range, battery life (e.g., the temperature at which the battery begins to degrade), battery SoH, battery SoC, likelihood of thermal runaway (e.g., at a given state of charge, absolute threshold for a given battery chemistry, battery manufacturer requirements, warranty requirements, etc.), safety margins, flight planning (e.g., different battery temperature requirements are selected for each leg of a flight or for each flight in a series of flights), and / or otherwise. In a specific embodiment, the expected temperature change during the flight may be subtracted from the battery temperature requirement to obtain the temperature set point.

[0164] Block S100 may include adjusting a temperature set point of the battery based on the battery SoC (e.g., current SoC, expected SoC at takeoff, expected SoC profile during flight), which serves to reduce or mitigate the risk of thermal runaway propagating at high battery SoC. Adjusting the temperature set point may include determining the likelihood of a thermal event at a given SoC and expected power consumption, determined based on the current SoC, takeoff SoC, cooling rate, heat redistribution rate, estimated heat generated during charging, and / or any other suitable parameters. Determining the likelihood of a thermal event may be determined based on a probability of heat propagation at a particular SoC, a lookup table, a machine learning model, and / or other suitable techniques. The likelihood of a thermal event may be predicted once with respect to the navigation profile, over a time series model of the expected navigation profile, periodically with respect to the expected navigation profile, with respect to a sustained function approximation of the navigation profile / SoC, and / or otherwise. In a first example, the temperature set point for the battery for a 10 mile trip is determined to be 40° C. The battery pack has a 95% SoC. Block S100 adjusts the temperature set point down to 30° C. to ensure that a thermal event cannot propagate given the high SoC.

[0165] Because the vehicle is preferably optimized for low mass and therefore in some alternatives lacks active regulation devices (e.g., for the battery), the temperature set point is preferably determined according to a calculated temperature change during flight (e.g., calculated based on a flight profile). However, the temperature set point can be determined based on the desired aircraft component temperatures (e.g., wing temperature, nacelle temperature, hub temperature, cabin temperature), heat production of other components, and / or other parameters for which the battery pack serves as a heat source. For example, the flight profile can include the takeoff weight of the vehicle, the flight distance, and the estimated flight time for each phase of the flight, and the associated expected power expenditure. In this example, block S100 can include calculating the discharge characteristics of the battery pack during flight based on the flight profile (e.g., including the flight plan), calculating the expected temperature rise during the flight, and determining a pre-flight temperature set point such that the battery pack temperature remains within a predetermined range (e.g., determined to prevent the occurrence of a thermal event). In related embodiments, the basis for determining the temperature setpoint may additionally or alternatively include vehicle mass (loaded or unloaded), vehicle drag profile, ambient temperature, expected thermal load from the cabin (e.g., based on the difference between ambient temperature and current / setpoint cabin temperature), energy discharge profile, and / or any other suitable predetermined or dynamically determined time-series quantified aspects of vehicle progression (e.g., cruising).

[0166] In a second alternative, the temperature setpoints can be determined heuristically (eg, based on the flight plan).

[0167] In a third alternative, the temperature set point for the battery pack can be predetermined (eg, an absolute maximum, a static set point, etc.).

[0168] In a fourth alternative, the temperature set point can be determined based on a user input (e.g., a cabin temperature set point). For example, the temperature set point can be calculated based on the current cabin temperature, the cabin temperature set point, an estimated amount of heat generated by passengers, an estimated amount of heat generated by the battery during operation, an estimated ambient temperature during flight, and / or other parameters.

[0169] In a fifth alternative, the temperature setpoint can be determined from a lookup table (e.g. relating flight parameters such as flight length or aircraft weight to temperature setpoints or expected temperature rise, relating cabin temperature setpoints and optionally battery temperature setpoints to flight parameters).

[0170] In a sixth alternative, the temperature set point can be determined by a trained neural network. However, the temperature set point can also be determined differently.

[0171] In a seventh alternative, the temperature set point can be determined based on an optimal discharge temperature (e.g., a temperature or temperature range at which power delivery is maximally efficient) associated with a particular chemistry of the battery pack. The temperature set point can be equal to the optimal discharge temperature, but can additionally or alternatively be less than the optimal discharge temperature such that the battery pack is at the optimal discharge temperature for a desired period of time during the voyage (e.g., for a maximized period of time, for a period of time associated with higher risk vehicle operations such as takeoff and / or landing, etc.) as a result of warming of the battery pack during discharge. However, the temperature set point can additionally or alternatively be suitably determined otherwise.

[0172] In an eighth alternative, the expected temperature increase can be negative (eg, a temperature change, a temperature decrease, etc.).

[0173] In a ninth alternative, the temperature set point can be determined based on the cabin temperature set point. In a specific embodiment, the difference between the ambient temperature and the cabin temperature set point can be used to determine an expected heat load to maintain the cabin set point temperature, and the temperature set point of the battery can be adjusted (e.g., according to the specific heat of the battery and / or by increasing the thermal mass by at least the expected heat load).

[0174] Block S150 includes regulating the battery pack temperature to a temperature set point. Alternatively, vehicle operation (e.g., takeoff or flight) can be adjusted with respect to the battery pack temperature to satisfy the temperature set point. Block S150 functions to regulate the battery pack, which can include heating and / or cooling the battery pack to avoid the need for active temperature control and maximize battery pack performance during vehicle operation. The temperature set point is preferably a takeoff temperature set point, but can additionally or alternatively be an operational set point or any other suitable set point. Block S150 is preferably performed while the on-board components (e.g., battery pack and on-board circulation subsystem) are coupled to the off-board components (e.g., on-board circulation subsystem, heat exchanger, on-board pump, etc.), which is preferably performed prior to vehicle operation for navigation (e.g., flight). However, block S150 can additionally or alternatively be performed at any other suitable time. S150 is preferably performed during battery pack charging (e.g., to a predetermined SOC), but can additionally or alternatively be performed independently of battery pack charging (e.g., only the battery pack is cooled while the aircraft is grounded, the aircraft takes off only after the takeoff temperature setpoint is reached, etc.).

[0175] In a variation, block S150 can include connecting the circulation subsystem to an external cooling system, which can be performed manually (e.g., by a user), automatically (e.g., by robotic and / or electromechanical connection), and / or otherwise.

[0176] In a variation, block S150 can include actively circulating the working fluid through the combined on-board and on-board circulation subsystem using an on-board pump so that heat is exchanged between the heat exchanger and the environment (e.g., to receive heat or reject heat to the environment) and between the battery pack and the working fluid (e.g., to heat or cool the battery pack to a set point temperature). In an alternative variation, block S150 can include allowing the battery pack to passively cool to a temperature of the environment (e.g., the temperature set point is substantially equal to the temperature of the environment and it is determined that the battery pack will passively reach thermal equilibrium with the environment prior to the start of navigation and operation of the vehicle). In a third variation, S150 can include cooling or warming the battery pack to a charging temperature range and / or maintaining the battery pack temperature within the charging temperature range by circulating fluid through the circulation subsystem. In this variation, S150 can optionally include cooling or warming the battery pack to a takeoff temperature set point after charging is completed.

[0177] Block S150 may include controlling the on-board cooling system operation, which may be controlled at a BMS (e.g., on-board BMS), at the battery electronics, at the vehicle controller, at the charging station, off-vehicle, in-vehicle, and / or at any other suitable endpoint. Block S150 may include controlling the circulation subsystem (e.g., circulating the working fluid), which may optionally include regulating the flow rate through a pump (e.g., on-board and / or off-board). Block S150 may include actively circulating the working fluid, and may optionally include (actively) circulating a second working fluid (e.g., refrigerant). Block S150 may include actively removing heat from the working fluid, such as with an on-board refrigeration system (e.g., including a compressor, TXV, evaporator, and condenser, examples of which are shown in FIGS. 22A-B). In a specific embodiment, S150 controls the flow rate of the working fluid during battery conditioning to be substantially the same as the flow rate during flight (e.g., takeoff, landing, forward flight, etc.) (e.g., sustained, steady state pump operation, etc.).

[0178] In a specific example, the battery pack temperature can be reduced during cargo (e.g., passenger) loading / unloading and / or battery charging. The rotation times for unloading, loading, battery charging, and / or conditioning can be 3 minutes, 5 minutes, 7 minutes, 10 minutes, 12 minutes, 15 minutes, 20 minutes, 35 minutes, 30 minutes, 45 minutes, less than 1 hour, more than 1 hour, any range bounded by the aforementioned values, and / or any other suitable rotation times. The temperature decrease during the vehicle rotation time can be <5°C, 5°C, 10°C, 15°C, 25°C, 30°C, 35°C, >35°C, any range bounded by the aforementioned values, and / or any other suitable temperature change. In a first example, the battery pack temperature decreases (e.g., continuously, monotonically, etc.) during simultaneous charging and conditioning (as shown in the examples in Figures 12 and 13). In a second example, the temperature increases and / or remains the same during simultaneous charging and conditioning and then decreases. In a third embodiment, the battery temperature is reduced below the temperature set point during conditioning and then subsequently held at or below the temperature set point during subsequent charging and conditioning.

[0179] In a first example, battery charging may include, concurrently with block S150 or otherwise, electrically connecting the battery pack to a charger (e.g., via an electrical connector), determining an SoC threshold based on expected power consumption and battery power capacity for the navigation profile, determining satisfaction of a charging condition (e.g., an SoC equal to or exceeding the SoC threshold), and in response to satisfaction of the charging condition, ceasing charging of the battery pack and / or electrically disconnecting the battery pack from the charger.

[0180] Block S150 may optionally include decoupling the circulation subsystem from the on-board cooling system, which may occur manually (e.g., by a user) and / or automatically via a locking mechanism. In an alternative embodiment of the system including a fluid locking mechanism, block S150 may include determining (e.g., by a BMS, vehicle controller, charger, or other endpoint) satisfaction of a condition for fluid circulation (e.g., a decoupling condition) and, in response, decoupling (e.g., at the fluid locking mechanism) the on-board cooling system. The condition may be completion of battery conditioning, a flow rate mismatch (e.g., between a flow rate commanded by the BMS and a measured flow rate), a flow temperature mismatch (e.g., between an expected flow temperature and a measured flow temperature), and / or any other suitable condition for fluid circulation.

[0181] Block S200 includes determining an instantaneous temperature of the battery pack. Block S200 functions to determine a temperature of the battery pack for use in regulating the temperature of the battery pack (e.g., toward a setpoint temperature as determined according to one or more variations of block S100, downward to avoid the risk or occurrence of a thermal event, etc.). Block S200 may include directly measuring the instantaneous temperature of the battery pack (e.g., with a temperature sensor), inferring or estimating the temperature of the battery pack (e.g., based on the output of another sensor that is not a temperature sensor, according to a thermal model of the battery pack, etc.), calculating the temperature of the battery pack (e.g., based on the output power of the battery pack), and / or otherwise suitably determining the temperature. The determined temperature may be a temperature at a physical point within the battery pack (e.g., an arbitrary point, a point coupled to a sensor input, etc.), a temperature distribution (e.g., a three-dimensional distribution) within the battery pack (e.g., at a per-cell resolution, at a finer or coarser resolution than per-cell, etc.), a rate of temperature change of a point within the battery pack, a distribution of the rate of temperature change within the battery pack, and / or any other suitable quantification or derivative of temperature.

[0182] Block S200 may be performed during battery conditioning (e.g., according to one or more variations of block S150), e.g., the instantaneous temperature of the battery pack may be measured to determine whether the battery pack has reached a determined temperature setpoint. Block S200 may also be performed during vehicle operation (e.g., flying, driving, crossing water, etc.), e.g., block S200 may include monitoring temperature and / or temperature-related data during use to determine a thermal state of the battery pack.

[0183] Block S200 may include detecting a thermal event. Detecting a thermal event may include determining that a temperature and / or a rate of temperature rise exceeds a threshold based on a temperature or temperature change rate measurement. Block S200 may include inferring a thermal event based on a signal indicative of a thermal event (e.g., a current spike or drop, a power fluctuation, etc.) in addition to or as an alternative to a direct measurement of temperature or other fire detection measurements (e.g., smoke detector, fire rope, etc.). For example, block S200 may include detecting propagation of a thermal anomaly among multiple cells in a battery pack based on a measured rate of temperature rise in multiple adjacent cells. In another example, block S200 may include detecting a thermal event in a battery pack based on an output current drop resulting from an internal short circuit. However, block S200 may preferably include detecting a thermal event otherwise.

[0184] Block S200 can include predicting a thermal event. The thermal event can be predicted based on a thermal model of the battery pack, and block S200 can include determining that a thermal event is likely to occur (e.g., associated with a quantifiable probability above a threshold) based on vehicle operation data (e.g., flight data, navigation data, etc.). For example, block S200 can include predicting that a thermal runaway is likely based on flight data (e.g., impact sensor readings, messages from a flight computer, etc.) indicating that an emergency landing has occurred.

[0185] Block S200 may optionally include notifying a user, pilot, remote server, third party of the thermal event and / or current temperature. Notification may occur at any suitable time, which may be prior to flight, during calibration, during battery charging, during flight (e.g., periodically, continuously, etc.), in response to thermal event detection, and / or any other suitable time.

[0186] Block S200 may optionally include controlling the vehicle based on the temperature, which may include, in response to a temperature exceeding a threshold, continuing route plan execution, reducing / disconnecting power draw from the battery pack, performing an emergency landing, dynamically adjusting the route plan during the route, and / or otherwise controlling the vehicle if the temperature is within a predetermined temperature range (e.g., below absolute battery maximum, within a threshold deviation from an expected temperature profile, no current thermal event, etc.).

[0187] Block S200 may additionally or alternatively include determining the thermal event in any other suitable manner.

[0188] Block S250 includes redistributing heat within the battery pack based on the temperature of the battery pack. Block S250 functions to utilize the thermal mass of the battery pack as a whole to absorb excess heat resulting from a thermal event within a portion of the battery pack. Block S250 can also function to achieve temperature uniformity within the battery pack. Block S250 can also function to prevent a thermal event from occurring (e.g., transferring heat away from a malfunctioning cell to prevent thermal runaway) and / or from worsening (e.g., transferring heat away from a cell experiencing thermal runaway to prevent propagation). S250 can be implemented by an on-board pump, an off-board pump, and / or any other suitable pump.

[0189] Block S250 may include controlling a flow rate of an on-board pump operable to circulate the working fluid through the closed on-board portion of the on-board circulation subsystem. Block S250 may include determining a flow rate based on received data (e.g., thermal event data, flight data, navigation data, etc.) and controlling the on-board pump (e.g., with a pump controller) to implement the determined flow rate.

[0190] Block S250 is preferably performed during vehicle operation away from infrastructure equipment (e.g., decoupled), and thus preferably does not include active conditioning of the battery pack (e.g., to cool the battery pack as a whole, to warm the battery pack as a whole), but rather preferably includes redistributing heat of the battery pack across the thermal mass of the battery pack (e.g., transferring excess heat from one cell to another cell or cells that are at or below a nominal temperature). However, block S250 may additionally or alternatively include exchanging heat between the on-board system and the environment without using a dedicated high-throughput heat exchanger such as one integrated with the infrastructure equipment (e.g., through a radiator section of the on-board circulation subsystem).

[0191] Block S250 can be implemented in response to a detected thermal event or other system failure as a mechanism for fail-safe and / or fault-tolerant operation of the vehicle. For example, block S250 can include operating an on-board pump (e.g., in a battery loop) at a maximum flow rate in response to a detected thermal event.

[0192] Block S250 can be performed based on situational data. For example, the situational data can include flight information such as altitude and an estimated duration and power profile required before performing an emergency landing, and block S250 can include determining a maximum allowable flow rate based on remaining energy in the battery pack (to power an on-board pump) and the situational data, and operating the on-board pump at the determined maximum allowable flow rate. In a related embodiment, block S250 can include preventing activation of the on-board pump despite the occurrence of a thermal event if on-board energy would be better utilized in powering the propulsion system (e.g., allowing the aircraft to land safely, even while sustaining damage to the battery pack).

[0193] Block S250 can be implemented based on a predicted thermal event. For example, block S250 can include proactively operating an on-board pump at maximum flow rate in response to a prediction of a possible thermal runaway (e.g., based on detection of a hard landing, the output of an impact sensor, an emergency switch activated by a vehicle operator, etc.).

[0194] Block S250 may optionally include detecting a leak in the circulation subsystem. In response to detecting a leak, block S250 may automatically shut down a pump, minimize the amount of fluid loss and / or the likelihood of an electrical short, send a notification (e.g., to a user in the aircraft, a pilot, a central management system, etc.), or otherwise mitigate a failure resulting from the leak. Leak detection may utilize a set of resistive, capacitive, and / or optical sensors, and / or any other suitable sensors. A leak may be detected as a loss of working fluid volume from the fluid envelope (e.g., based on time series sensor measurements) above a predetermined loss threshold (e.g., 0.5 L, 1 L, etc.), a change (e.g., increase, decrease) in working fluid resistivity, detection of an open circuit (e.g., by current flowing through the working fluid), and / or otherwise determined.

[0195] In a first alternative, Block S250 does not remove a substantial amount of heat from the thermal system collectively defined by the battery pack and the circulation subsystem during flight. In a first example, less than 50%, 25%, 10%, 5%, 3%, 1% of the heat generated (or total heat) is rejected during flight.

[0196] In a second variant, block S250 does not remove a substantial amount of heat from the battery pack and / or vehicle systems during flight. In a first example, less than 10%, 5%, 1% of the heat generated or total heat is removed during flight. In a second example, the temperature of the battery pack (e.g., net temperature, maximum individual cell temperature, etc.) increases monotonically during flight (e.g., the temperature change rate may be uniform or non-uniform, but strictly greater than zero, persistently, etc.). In a third example, the thermal energy contained within the thermal system and working fluid of the battery pack increases persistently during flight (e.g., the temperature change rate may be uniform or non-uniform, but strictly greater than zero). In a specific example, the total thermal energy of the thermal system, including the battery pack, the first working fluid, the second working fluid, and the cabin air, increases (e.g., persistently, bursty, monotonically, etc.) during flight (e.g., during an operating session defined by takeoff and landing).

[0197] In a third alternative, Block S250 removes heat from the battery pack and / or vehicle systems during travel.

[0198] In a fourth alternative, block S250 continuously redistributes heat during cruising. In a specific embodiment, the working fluid is circulated at a maximum flow rate (e.g., absolute maximum, maximum sustained flow rate) of the pump, on-board heat exchanger, and / or fluid manifold (or envelope). In a second specific embodiment, the flow rate of circulation during cruising is substantially the same circulation, such as within 50%, within 25%, within 10%, within 5%, within 3%, within 1%, exactly the same and / or otherwise equivalent, during battery conditioning.

[0199] In a first specific example, the active heating and / or cooling includes applying mechanical work to the working fluid to generate a steady state temperature difference between the working fluid and the battery pack (e.g., greater than 5° C., 10° C., 15° C., 20° C., 25° C., 50° C., etc.). In a second specific example, there is no active heat removal and / or active cooling of the battery pack during flight, and there is active heat removal and / or active cooling of the battery after flight. In a third specific example, there is no active cooling of the collective thermal system of the battery pack and circulation subsystem (e.g., including the fluid manifold and the volume of working fluid on-board the aircraft). In a third specific example, there is no forced convection between the environment and the collective thermal system, including the battery pack and circulation subsystem.

[0200] Block S300 includes regulating the cabin temperature using an onboard thermal management subsystem of the vehicle during the operating session. Block S300 functions to use the onboard thermal management subsystem (and in some variations, the infrastructure subsystem) to modify and / or maintain the cabin temperature consistent with (e.g., within a threshold range of) a set cabin temperature. The set cabin temperature, which may be accessed, may be a cabin temperature setpoint that is limited to a design range (e.g., 15-25° C., any other suitable range, etc.), and / or may not be limited by a design range.

[0201] The cabin temperature setpoint may be manually determined (e.g., by a passenger, by an operator, etc.), dynamically determined (e.g., automatically selected based on design ranges, user preferences, current battery temperature, battery thermal operating range, etc., optimized, using a look-up table, etc.), or otherwise determined.

[0202] In one alternative, achieving the cabin temperature setpoint may be prioritized over battery performance and / or life during cabin temperature setpoint determination and / or onboard thermal management subsystem operation. In a second alternative, battery performance and / or life may be prioritized over the cabin temperature setpoint. In a third alternative, block S300 may include storing thermal energy from the cabin air in the battery pack in a cabin cooling mode (an example is shown in FIG. 20).

[0203] Block S300 may include circulating cabin air within the cabin through an air manifold in any suitable manner (e.g., by controlling fans and / or valves in the air manifold). Circulating cabin air may include recirculating cabin air (e.g., through interior vents and cabin air intakes), receiving outside air (e.g., via an inlet orifice), and exhausting cabin air (e.g., via an outlet orifice).

[0204] Block S300 may include redistributing heat between the cabin air and the battery pack, which may include controlling the onboard thermal management subsystem in a cabin cooling mode, controlling the onboard thermal management subsystem in a cabin heating mode, and thermally decoupling the cabin air and the battery pack. The cabin air and battery pack may be thermally decoupled by terminating working fluid circulation through the cabin loop, ceasing pump operation in the cabin loop, engaging a valve (e.g., a four-way valve), isolating fluid on a first half (including the battery heat exchanger) and a second half (including the cabin heat exchanger) of the working fluid loop, and / or otherwise thermally decoupling the cabin air and the battery pack.

[0205] Block S300 can occur at any suitable time. Block S300 can occur during operation (e.g., while the vehicle is airborne, in a forward flight mode, in a hover flight mode), in parallel with charging the vehicle, while the vehicle is on the ground, while the vehicle is idle, and / or any other suitable time.

[0206] In some variations, the performance of the onboard thermal management subsystem (e.g., the accuracy and precision of cabin temperature relative to the set temperature) may depend on the ambient temperature. In a specific example of such a variation, the performance is dictated by the ambient temperature according to a trimodal methodology. That is, in a first case, where the ambient temperature is about -40°C to about -10°C, the cabin temperature is allowed to deviate below the set temperature as long as it is above 0°C; in a second case, where the ambient temperature is about -10°C to about 40°C, the cabin temperature is not allowed to deviate substantially from the set temperature (e.g., HVAC performance is preferably not affected); and in a third case, where the ambient temperature is about 40°C to about 50°C, the cabin temperature is allowed to deviate above the set temperature as long as it is below 30°C. In an example of the second case, block S300 may include delivering up to about 3.5 kW of cooling power to the cabin and up to about 2.5 kW of heating power to the cabin within the set temperature range of about -10°C to about 40°C.

[0207] However, Block S300 may additionally or alternatively include managing cabin temperature in any other suitable manner.

[0208] Although omitted for brevity, the preferred embodiments include all combinations and permutations of the various system components and / or method blocks, which may be combined in any suitable permutation or combination and / or omitted, in whole or in part, from variations of the preferred embodiments.

[0209] As those skilled in the art will recognize from the foregoing detailed description, and from the figures and claims, modifications and variations can be made to the preferred embodiments of the invention without departing from the scope of the invention, which is defined in the following claims.

Claims

1. 1. A method comprising: Flying an electric aircraft, the electric aircraft comprising a cabin and a battery pack; ventilating air outside the cabin through an exhaust nozzle, the ventilating including increasing at least one of air pressure at the exhaust nozzle or velocity at the exhaust nozzle using a fan positioned at the exhaust nozzle; and Cooling the cabin while flying the electric aircraft, comprising: transferring thermal energy between a first working fluid and cabin air in a first heat exchanger; transferring the thermal energy from the first working fluid to a second working fluid in a second heat exchanger, the second working fluid being in thermal communication with the battery pack; storing a first portion of the thermal energy within a thermal mass of the battery pack; Including, A method comprising:

2. 10. The method of claim 1, further comprising preconditioning the electric aircraft comprising replacing a first portion of the second working fluid with a second portion of the second working fluid from a ground infrastructure while the electric aircraft is grounded.

3. The first working fluid is in a first fluid loop, and cooling the cabin includes: in response to determining satisfaction of a cabin temperature threshold, dividing the first fluid loop into a first sub-loop and a second sub-loop, a first portion of the first working fluid being contained within the first sub-loop and a second portion of the working fluid being contained within the second sub-loop, the first sub-loop comprising the first heat exchanger, and the second sub-loop comprising the second heat exchanger; transferring thermal energy from the first sub-loop to the second sub-loop using a heat pump; The method of claim 1 further comprising:

4. 4. The method of claim 3, wherein a total thermal energy of a thermal system comprising the battery pack, the first working fluid, the second working fluid, and the cabin air increases continuously during flight.

5. and regulating a flow of outside air into the cabin during flight; Using a turbine to regeneratively charge the battery pack while simultaneously reducing the thermal energy of the flow. The method of claim 1 , comprising:

6. The method of claim 5 , further comprising balancing the cabin air pressure with ambient pressure while flying the electric aircraft.

7. The method of claim 1 , further comprising blowing a portion of the cabin air across avionics prior to ventilating the portion of the cabin air.

8. 2. The method of claim 1, wherein the battery pack comprises a first cell and a second cell, and wherein cooling the cabin further comprises convectively balancing thermal energy between the first cell and the second cell using a third heat exchanger.

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