Patent Application
20240194978
The present application claims benefit of prior filed Chinese Patent Application No. 202211571937.5 filed Dec. 8, 2022, which is hereby incorporated by reference herein in its entirety.
The present invention generally relates to electrified vehicles and more particularly relates to phase change material energy storage for heating and cooling selected systems of the electric vehicle's drive.
Electric drive systems may be found in a number of applications including mobile and stationary platforms. Electrified vehicles may include aircraft, automobiles and watercraft. Stationary applications may include gensets, pumping stations, and other applications. For electric motor driven systems such as used in mobile platforms/vehicles and stationary platforms, the batteries include energy storage elements that are preferably maintained in an operating temperature range that is between a lower threshold and an upper threshold for efficiency and system longevity. Heating of batteries may be effected by electric heaters, which depletes battery charge. Cooling of batteries may be effected by conventional radiator devices. Electric powered heaters used to heat battery systems drain power that would otherwise be available for drive/propulsion purposes. As such, electric powered heaters reduce efficiency and deplete stored battery power without directly serving the primary system purposes. The effects of heating electrical consumption may be exacerbated in low temperature conditions.
Accordingly, it is desirable to provide improved systems and methods that enable selectively removing heat from drive systems and that enable selectively delivering heat to battery systems without reducing efficiency and without depleting the stored energy. It is also desirable to provide effective heating without large electrical consumption in a cost-effective manner. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.
This summary is provided to describe select concepts in a simplified form that are further described in the Detailed Description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
In a number of embodiments, an electric drive system includes an electric drive unit coupled with a battery system and a power conversion system. An energy storage unit contains at least one phase change material and is configured to manage thermal energy. A fluid system extends through the drive unit, the battery system, the power conversion system, and the energy storage unit. The fluid system is configured to collect heat from the drive unit, the battery system and the power conversion system; selectively store the heat in the energy storage unit in the phase change material; and selectively supply heat from the energy storage unit to the battery system.
In a number of other embodiments, a method of operating an electric drive system includes coupling an electric drive unit with a battery system and a power conversion system. At least one phase change material is contained in an energy storage unit and is configured to manage thermal energy. A cooling unit is configured to exchange heat. A fluid system extends through the electric drive unit, the battery system, the power conversion system, the energy storage unit, and the cooling unit. The fluid system collects heat from the electric drive unit, the battery system and the power conversion system. The cooling system selectively expels the heat. The energy storage unit selectively stores the heat in the phase change material. Heat from the energy storage unit is selectively supplied to the battery system.
In a number of additional embodiments, a drive system of an aircraft includes an electric drive unit coupled with a battery system and a power conversion system. An energy storage unit contains at least one phase change material and is configured to manage thermal energy. A cooling unit is configured to exchange heat. A fluid system extends through the electric drive unit, the battery system, the power conversion system; the energy storage unit, and the cooling unit. A controller is coupled with the fluid system. The controller and the fluid system are configured to: collect heat from the electric drive unit, the battery system and the power conversion system; selectively expel the heat through the cooling system; selectively store the heat in the energy storage unit in the phase change material; and selectively supply heat from the energy storage unit to the battery system.
The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and
The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.
The various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. Some of the embodiments and implementations are described above in terms of functional and/or logical block components (or modules) and various processing steps. Such block components (or modules) may be realized by any number of hardware, software, and/or firmware components configured to perform the specified functions.
The various illustrative logical blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed in a controller with a general purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a digital signal processor core, or any other such configuration.
The steps of a process, method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in any form of storage medium known in the art. An exemplary storage medium may be coupled to the processor such that the processor reads information from, and writes information to, the storage medium. In the alternative, the storage medium may be integral to the processor.
Broadly, the exemplary embodiments discussed herein provide systems and methods for heating and cooling aspects of an electric drive system without drawing excessive power from the batteries. In embodiments, an electric drive system includes an electric drive unit coupled with a battery system and a power conversion system. In certain embodiments, the battery system may be any form of energy storage system that delivers electrical energy storage capabilities. Accordingly, as used herein, the term “battery system” is any system that stores electric energy for use by an electrical consuming device. The electric drive system of the current disclosure may include an energy storage unit containing at least one phase change material, and is configured to manage thermal energy collection, storage, and reuse. A cooling system configured to exchange heat may be included in or with the electric drive system. For example, a fluid system with a radiating heat exchanger may be included to remove and return heat from parts of the electric drive system and/or its ancillary systems. The fluid system may include conduits extending through the drive unit, the battery system, the power conversion system. The fluid system may also include the energy storage unit and the cooling system. The fluid system may operate to collect heat from any or all of the drive unit, the battery system and/or the power conversion system. The fluid system may be operated to selectively expel the heat through the cooling system. The fluid system may be operated to selectively store the heat in the energy storage unit in one or more one phase change materials. The fluid system may be operated to selectively supply heat from the energy storage unit to the battery system. In embodiments, the heat may be collected and stored to provide a mechanism for cooling of the electric drive system.
Referring to
A thermal management system 40 is coupled with the drive unit 24, the power conversion system 26 and the battery system 28. In operation, the drive unit 24, the power conversion system 26 and the battery system 28 may each generate heat. The thermal management system 40 includes a fluid system 42 that includes a number of fluid conduits for directing fluid flow through the various components. For example, the drive unit 24, the power conversion system 26 and the battery system 28 may each have internal flow conduits through which the fluid is circulated.
A cooling unit 46 is a part of the fluid system 42. The cooling unit 46 includes a heat exchanger 48, such as a tube and fin or other type of heat exchanger, for removing heat from the fluid in the fluid system 42, such as by radiating the heat to atmospheric air. The cooling unit 46 may include a fan to accelerate heat rejection. A pump 50 is included in the fluid system 42 for circulating the coolant fluid through the drive unit 24, the power conversion system 26, the battery system 28 and the cooling unit 46. In operation, the pump 50 circulates the fluid through, and collecting heat from, the drive unit 24, the power conversion system 26 and/or the battery system 28 and selectively expelling the heat through the heat exchanger 48 of the cooling unit 46.
The fluid system 42 includes a number of control valves 52, 54, 56 to control fluid flow through its various circuits. The control valves 52, 54, 56 may be of various constructions and in the current embodiment are each three-way, electrically operated valves with three ports “A,” “B,” and “C,” each. For example, each valve 52, 54, 56 includes a respective actuator 62, 64, 66 to operate. The actuators 62, 64, 66 may be rotary or linear actuators to move the control valves 52, 54, 56 in response to control signals to connect a selective two of its ports while closing the third port, to open/connect all three ports, or to close all three ports. For example, to provide cooling of the drive system 22 by the cooling unit 46, control valve 52 is moved to connect port A with port B and close port C, control valve 54 is moved to connect port A with port B and close port C, and control valve 56 may be moved to close all ports A, B and C. As such, the pump 50 circulates the fluid through the drive system 22, including the drive unit 24, the power conversion system 26, the battery system 28, and then through the cooling unit 46. This includes circulating the fluid through a conduit 70, from the pump 50 to the battery system 28, through a conduit 72 from the battery system 28 to the power conversion system 26, through a conduit 74 from the power conversion system 26 to the drive unit 24, through a conduit 76 from the drive unit 24 to the cooling unit 46 and through a conduit 78 from the cooling unit 46 to the pump 50, completing the circuit.
The thermal management system 40 includes an energy storage unit 80 connected in the fluid system 42. The energy storage unit 80 may include a container 82 through which fluid may be circulated and may include at least one phase change material (PCM) 84, 86 inside the container 82. For example, the PCM(s) 84, 86 may be substances that absorb and/or release substantial amounts of latent heat during a change in their physical state (i.e., from solid to liquid and vice versa). When experiencing a given temperature change, the PCM(s) 84, 86 absorb more heat and with better heat storage performance as compared to a material without phase change (where energy is stored as sensible heat). The PCM(s) 84, 86 may be selected to have a phase change temperature that matches the needs of the thermal management system 40 as further described below.
The thermal management system 40 may be operated in heating and cooling states. For example, during relatively low ambient temperature conditions such as experienced in winter, the thermal management system may be operated in a heating state. Also for example, during relatively high ambient temperature conditions such as experienced in summer, the thermal management system 40 may be operated in a cooling state. In each of the heating state and the cooling state, the thermal management system 40 may be operated in a charge mode and in a discharge mode. In the heating state, charge means the energy storage unit 80 absorbs and stores heat. In the cooling state, charge means the energy storage unit 80 absorbs and stores cooling energy (release heat). In the discharge mode the energy storage unit 80 discharges stored heat. Charging in the heating state may include a peak cooling demand mode of operation and an off-peak cooling demand mode of operation as described in more detail below. Discharge during the cooling state may include a peak cooling demand mode of operation and an off-peak cooling demand mode of operation as described in more detail below.
In the heating state and charge mode and without a peak cooling demand, the thermal management system 40 is operated to collect heat from the drive system 22 and store it in the energy storage unit 80 as illustrated in
In the heating state and charge mode without peak cooling demand of
Referring to
Referring to
Referring to
Referring to
Referring to
The thermal management system 40 includes a control system 100 with a controller 102 that controls operation of the thermal management system 40, including the control valves 52, 54, 56, the cooling unit 46, the energy storage unit 80, and the pump 50. In addition, the control system 100, through the controller 102 and/or additional controllers, may control operation of the drive unit 24, the power conversion system 26 and the battery system 28 to deliver the desired operational performance. The controller 102 may be coupled with a sensor system 104. The sensor system 104 includes one or more sensing devices that sense observable conditions of the electric vehicle 20 and/or of the thermal management system 40. In this embodiment, the sensing devices include, but are not limited to, an ambient temperature sensor, a battery system temperature sensor, a power conversion system temperature sensor, a drive unit temperature sensor, a thermal management unit temperature sensor and various fluid temperature sensors. It will be appreciated that the temperatures of various components of the thermal management system 40 may be determined from the various fluid temperature sensors that monitor temperatures of the fluid in the fluid system 42.
In general, the controller 102 uses the available inputs, including those from the sensor system 104 and from actuators identified herein, to provide the controller 102 with parameter data to effectively govern various functions, including of the thermal management system 40. For example, based on data input, the controller 102 computes and controls delivery of the appropriate control signals for operation of the control valves 52, 54, 56. The controller 102 may also control the power conversion system 26 and the drive unit 24, such as to deliver the appropriate amount of torque requested of the drive unit 24.
In the electric vehicle 20, it may be desirable to maintain the batteries in an optimal temperature range such as between 25 degrees Celsius and 45 degrees Celsius when the system is operating. Pre-heating of the battery system 28, such as of the energy storage elements 36 may be desired before starting electric vehicle 20, such as in low ambient temperature conditions. Pre-heating may also be desirable when initiating charging of the battery system 28. For example, when the temperature is below 0° C., pre-heating before charging is desirable. In addition, cooling of the drive unit 24, the power conversion system 26 and/or the battery system 28 may be desirable in both relatively high ambient temperature conditions (summer conditions) and relatively low ambient temperature conditions (winter conditions).
In relatively low ambient temperature conditions, cooling peak demand may call for cooling of the drive unit 24, the power conversion system 26 and/or the battery system 28. The energy storage unit 80 may be used to supply cooling by capturing heat extracted from the drive unit 24, the power conversion system 26 and/or the battery system 28. Instead of releasing the heat to the air through the cooling unit 46, the energy storage unit 80 recycles the collected heat for later uses such as to preheat the battery system 28.
In relatively high ambient temperature conditions, cooling peak demands may be delivered by including a lower phase change temperature PCM 96 replacing the PCM(s) 84, 86. In relatively high ambient temperature conditions the cooling capacity of the cooling unit 46 may be limited and providing supplemental or alternative cooling via the energy storage unit 80 extends the cooling options.
The energy storage unit 80 provides both heating and cooling functions. By including PCM(s) 84, 86 with different phase change temperatures, or by recharging with a specifically selected PCM 96, multiple functions may be provided. For example, for heating purposes (e.g., preheating of the battery system 28), Na2SO4/10H2O which has a phase change temperature of 32.4 degrees Celsius, Na2SO3/5H2O which has a phase change temperature of 48.5 degrees C., or a composite material which has a phase change temperature of 58.4 degrees Celsius may be used. For cooling purposes, paraffin I which has a phase change temperature of 5 degrees Celsius or paraffin II which has a phase change temperature of 10 degrees Celsius may be used. By including one of the heating PCMs as PCM 84 and one of the cooling PCMs as PCM 86, both functions may be provided in one energy storage unit 80. In embodiments, by recharging with a cooling PCM 96 provides additional cooling capacity for meeting peak cooling demands in summer.
With reference to
The process 200 may begin 202 when initiation of operation of the electric vehicle 20 occurs. A determination 204 may be made, such as by the controller 102 with input from the sensor system 104, whether a temperature is above a threshold. For example, the determination 204 may be whether ambient temperature is relatively high in the summer (e.g., above 30° C.) or that the temperature of the battery system 28, the power conversion system 26 and/or the drive unit 24 is above a threshold indicating additional cooling is needed beyond the level from the cooling unit 46. When the determination is negative and the temperature is not above the threshold (e.g., winter conditions) and the drive system 22 is not at a peak cooling demand (which may also be determined by the controller 102 with input from the sensor system 104), the controller 102, via the actuators 62, 64, 66 sets 206 the control valves 52, 54, 56 to provide cooling through the energy storage unit 80 alone as described above in relation to
When the determination 204 is positive, meaning the monitored temperature is above the threshold (e.g., summer conditions), and the drive system 22 is not at a peak cooling demand (which may also be determined by the controller 102 with input from the sensor system 104), the process 200 via the controller 102 and the actuators 62, 64, 66 sets 212 the control valves 52, 54, 56 to provide cooling through the cooling unit 46 alone as described above in relation to
With reference to
The process 300 may begin 302 when initiation of operation of the electric vehicle 20 occurs. In some embodiments, the process 300 may begin 302 when a charging routine of the battery system 28 is initiated. A determination 304 may be made, such as by the controller 102 with input from the sensor system 104, whether a temperature is below a threshold. For example, the determination 304 may be whether the ambient temperature is relatively cool in winter (such as below 0° C.). When the determination 304 is negative, meaning the temperature is not below the threshold (and summer conditions exist), the process 300 proceeds to start 306 the drive unit 24 as preheating is not needed.
When the determination 304 is positive, meaning the temperature is below the threshold (and winter conditions exist), the process 300 via the controller 102 and the actuators 62, 64, 66, sets 308 the control valves 52, 54, 56 to provide heating through the circuit as described above in relation to
Accordingly, exemplary embodiments discussed herein provide additional cooling and heating through PCMs when needed, without depleting electric power from the battery system. Exemplary embodiments may find beneficial use in many applications, including electric drive systems in vehicles, in stationary machines, and in other applications.
While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202211571937.5 | Dec 2022 | CN | national |
