Method and control system for controlling a thermal management system of an eelctric vehicle

Abstract

There is provided a method of determining an operating mode of a thermal management system to precondition a traction battery of an electric vehicle for charging. The method comprises receiving an indication that a charging procedure is to be performed, obtaining information representative of a thermal energy transfer requirement for the traction battery representative of an amount of thermal energy to be transferred between the traction battery and the thermal management system to obtain a target battery charging temperature, obtaining information defining a plurality of operating modes of the thermal management system, each of the plurality of operating modes operable to satisfy the thermal energy transfer requirement, determining, for each operating mode, an energy cost associated with that operating mode using a model of the thermal management system, selecting an operating mode having a lowest determined associated energy cost, and providing an output indicating the selected operating mode.

Description

[0001] METHOD AND CONTROL SYSTEM FOR CONTROLLING A THERMAL MANAGEMENT SYSTEM OF AN ELECTRIC VEHICLE

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to a method and apparatus for determining an operating mode of a thermal management system of an electric vehicle to precondition a traction battery of the electric vehicle. In particular, the present disclosure relates to a method and apparatus for selecting an operating mode from a plurality of operating modes for the thermal management system based on an indication that a charging procedure is to be performed and on a predicted operating profile for the vehicle to arrive at the charging location. Aspects of the invention relate to a method, a computer readable medium, computer readable instructions, a control system and a vehicle.

[0004] BACKGROUND

[0005] When charging a traction battery of an electric vehicle, it is common to perform a preconditioning procedure to prepare the battery to receive the charging current. Preconditioning of the battery may allow the battery to charge at a faster rate and may increase the operational lifetime of the battery. However, the time taken to perform the preconditioning procedure upon arrival at a charging location may increase the overall time the vehicle is stationary at the charging location as the charging rate may be limited until the temperature of the battery reaches a target temperature range.

[0006] Furthermore, when providing thermal energy to raise the temperature of the fraction battery to a target charging temperature range, for example using a resistive heater, energy is drawn from the battery to perform the preconditioning procedure. This increases the energy to be replaced by charging the fraction battery, further increasing the time spent at the charging location.

[0007] It is an aim of the present invention to address one or more of the disadvantages associated with the prior art.

[0008] SUMMARY OF THE INVENTION

[0009] Aspects and embodiments of the invention provide an method of determining an operating mode of a thermal management system of an electric vehicle to precondition a traction battery of the vehicle for charging, a computer program, a control system, and a vehicle as claimed in the appended claims.

[0010] According to an aspect of the present invention there is provide a method of determining an operating mode of a thermal management system of an electric vehicle to precondition a traction battery for charging in response to an indication that a charging procedure is to be performed and based on a determination for each of a plurality of operating modes, each of the plurality of operating modes operable to perform the preconditioning of the traction battery for charging, an energy cost associated with the respective operating mode. The method further comprisies selecting an operating mode of the plurality of operating mode having the lowest determined energy cost and able to satisfy thermal requirements placed on the thermal management system.

[0011] Advantageously, an operating mode is selected that is able to precondition the battery ready for performance of the charging procedure and which may reduce the amount of electrical energy drawn from the battery for thermal management resulting in increased efficiency.

[0012] According to an aspect of the present invention there is provided a method of determining an operating mode of a thermal management system of an electric vehicle, the operating mode to precondition a fraction battery for charging, the method comprising receiving an indication that a charging procedure of a fraction battery of the electric vehicle is to be performed, obtaining information representative of a thermal energy transfer requirement for the fraction battery, the thermal energy transfer requirement representative of an amount of thermal energy to be transferred between the traction battery and the thermal management system to obtain a target battery temperature for charging of the traction battery, obtaining information defining a plurality of operating modes of the thermal management system, each of the plurality of operating modes operable to satisfy the thermal energy transfer requirement, determining, for each operating mode of the plurality of operating modes, an energy cost associated with that operating mode using a model of the thermal management system, selecting an operating mode having a lowest determined associated energy cost, and providing an output indicating the selected operating mode. Advantageously, the described method operates to choose an operating mode of the thermal management system of the vehicle to precondition the battery ready for charging in response to an indication received prior to arrival at a charging location that the traction battery is to be charged. In particular, the method determines an energy cost associated with each of a plurality of operating modes of the thermal management system that are able to provide the thermal energy required to precondition the battery to the desired temperature and selects an operating mode that is expected to be the most efficient, i.e. the operating mode of the considered operating modes having the lowest energy cost, which may lead to improved overall efficiency for the electric vehicle.

[0013] Optionally, the indication that the charging procedure of a traction battery of the electric vehicle is to be performed comprises an indication of a predicted period of time to elapse prior to beginning the charging procedure, wherein the thermal energy transfer requirement for the traction battery comprises a rate of thermal energy transfer between the traction battery and the thermal management system to obtain a target battery temperature for charging of the traction battery within the predicted period of time.

[0014] Advantageously, the indication may provide an indication of a start time for the charging procedure and / or a period of time until the procedure is expected to begin, for example an arrival time at a charging location. This information may be used to determine a rate of heating / cooling required to be provided to the traction battery by operating mode of the thermal management system to be ready for charging on arrival at a charging location.

[0015] Optionally, the energy cost for each operating mode comprises a respective thermal energy cost value representing an amount of thermal energy transferred off the electric vehicle and a respective actuator energy cost value representing an energy cost associated with operating the thermal management system in the respective operating mode.

[0016] Advantageously, the described method evaluates an energy cost for each potential operating mode and selects a mode having a lowest energy cost including both the cost of operating the thermal management system, for example energy required to operate a compressor, and also a thermal energy cost value representing an amount of thermal energy lost from the vehicle, e.g. via a radiator to the environment. Thus, the method is able to select an operating mode for the thermal management system that retains as much thermal energy as possible while preconditioning the fraction battery to the target temperature for charging, leading to increased efficiency overall.

[0017] Optionally, the indication comprises a characteristic associated with the charging procedure, the method further comprising determining the target temperature based on the characteristic.

[0018] Advantageously, the described method is able to take into account an expected characteristic of the charging procedure to tailor the target temperature to the expected charging procedure characteristics.

[0019] Optionally, the characteristic comprises an expected charging rate of the charging procedure.

[0020] Advantageously, the characteristic of the charging procedure may be a charging rate, or charging power, that is expected to be used to charge the fraction battery and provide a corresponding target temperature of the battery according to the expected charging rate.

[0021] Optionally, the thermal energy transfer requirement for the traction battery comprises one of: an amount of thermal energy to be supplied to the fraction battery; an amount of thermal energy to be extracted from the traction battery; or an indication that thermal energy may be supplied to or extracted from the fraction battery.

[0022] Advantageously, the thermal energy requirement may be signalled as a request for cooling / heating or an indication that the fraction battery is within a tolerable band of temperature around the target temperature and is therefore able to act as either a source or sink of thermal energy while remaining within the desired range. This information may allow a decision to be made to store thermal energy in a component for later use.

[0023] In embodiments, the electric vehicle comprises a plurality of components thermally coupled to the thermal management system, and at least one operating mode of the plurality of operating modes is operable to transfer thermal energy between at least one of the plurality of components and the fraction battery. Advantageously, thermal energy may be transferred to or from other components of the electric vehicle, such as drive units, to efficiently change the temperature of the traction battery to the target temperature. For example, thermal energy may be transferred from drive units to avoid use of an electric heater that would otherwise draw power from the battery which would have to be replaced during the charging procedure. Alternatively, thermal energy may be transferred from the fraction battery and stored in another component for future use, e.g. for cabin heating while stationary at the charging location.

[0024] Optionally, the plurality of components comprise at least one of: an electric drive unit; a heater; a heat pump; and a cabin air conditioning unit (such components may be called “thermal customers”).

[0025] Advantageously, an operating mode of the thermal management system may be selected taking into account the ability to source / sink thermal energy in any of the major thermal customers present on the vehicle, facilitating selection of an operating mode of the thermal management system that maximises the retention of thermal energy on the vehicle while meeting the thermal requirements of preconditioning the fraction battery.

[0026] In embodiments, obtaining information representative of the thermal energy requirement for the traction battery further comprises receiving a temperature signal indicative of a temperature of the traction battery, and determining, based on the temperature signal, the thermal energy transfer requirement of the fraction battery, the energy transfer requirement representative of an amount of thermal energy to be transferred to or extracted from the traction battery to obtain the target battery temperature for the charging procedure.

[0027] Advantageously, the thermal energy transfer requirement may be determined based on a current temperature of the battery to allow the amount of energy to be transferred to / from the battery to attain the target temperature to be easily and accurately determined.

[0028] In embodiments, the method further comprises receiving an ambient temperature value indicative of an ambient temperature of the environment, wherein the thermal energy transfer requirement for the traction battery is further determined based on the ambient temperature value.

[0029] Advantageously, the thermal energy transfer requirement may be further based on an external ambient temperature which is known to affect a desired temperature (e.g., a [particularly efficient operating temperature) of the fraction battery for charging.

[0030] In embodiments, the indication comprises route information indicative of a predicted route of the vehicle to arrive at a charging location and the method comprises predicting a future operating profile for the electric vehicle based on the route information, and determining the energy cost associated with each operating mode further based on the future operating profile.

[0031] Advantageously, the described method may obtain information relating to a route that is predicted to be taken by the vehicle to arrive at a charging location and uses that information to determine how the vehicle will be operated, for example highway driving, or upcoming congested traffic. Having determined how the vehicle will be operated, the thermal energy transfer requirement for the traction battery to arrive at the target temperature for that operating profile can be predicted, and the predicted thermal energy transfer requirements used to determine which operating mode of the thermal energy system is expected to be the most efficient

[0032] In embodiments, the method comprises determining a thermal energy value indicative of an amount of thermal energy that will be generated in the traction battery based on the future operating profile, and wherein obtaining information representative of the thermal energy requirement for the fraction battery further comprises determining, based on the determined thermal energy value, the thermal energy transfer requirement of the fraction battery, the energy transfer requirement representative of an amount of thermal energy to be transferred to or extracted from the fraction battery to obtain the target battery temperature for the charging procedure.

[0033] Advantageously, the future operating profile may be used to predict how much thermal energy will be generated within the battery due to operation of the vehicle to arrive at the charging location and this information used when selecting an operating mode to arrive at the target temperature.

[0034] In embodiments, the method comprises predicting for at least one further component of the electric vehicle, a thermal energy transfer requirement for the at least one further component based on the expected future operating profile, and wherein determining, for each operating mode of the plurality of operating modes, the energy cost associated with that operating mode is further based on the determined thermal energy transfer requirement for the at least one further component.

[0035] Advantageously, the future operating profile may be used to predict how much thermal energy will be generated within other components of the vehicle due to operation of the vehicle to arrive at the charging location and this information used to determine if other components may be predicted to have excess thermal energy that can be transferred to the battery for preconditioning, for example by transferring thermal energy from electric drive units of the vehicle to the traction battery.

[0036] Optionally, an operating mode satisfying the thermal energy transfer requirement comprises the operating mode being operable to cause the fraction battery to obtain the target battery temperature for charging of the traction battery at a predicted arrival time at the charging location.

[0037] Advantageously, the future operating profile or route information may allow an arrival time at the charging location to be predicted and used to ensure that battery is preconditioned ready for charging at the expected arrival time.

[0038] Optionally, obtaining the route information comprises receiving the route information from a satellite navigation apparatus.

[0039] Advantageously, route information may be obtained from a satellite navigation apparatus used by a driver of the vehicle to provide routing information to a programmed destination. This may increase confidence in the expected route of the vehicle.

[0040] According to another aspect of the invention, there is provided computer readable instructions which, when executed by one or more processors, cause the one or more processors to perform a method as disclosed herein.

[0041] Optionally, the computer readable instructions may be stored on a computer readable medium.

[0042] According to a further aspect of the invention, there is provided a control system for controlling a thermal management system of a vehicle, the control system comprising one or more processors collectively configured to receive an indication that a charging procedure of a traction battery of the electric vehicle is to be performed, obtain information representative of a thermal energy transfer requirement for the traction battery, the thermal energy transfer requirement representative of an amount of thermal energy to be transferred between the traction battery and the thermal management system to obtain a target battery temperature for charging of the traction battery, obtain information defining a plurality of operating modes of the thermal management system, each of the plurality of operating modes operable to satisfy the thermal energy transfer requirement, determine, for each operating mode of the plurality of operating modes, an energy cost associated with that operating mode using a model of the thermal management system, select an operating mode having a lowest determined associated energy cost, and provide an output indicating the selected operating mode.

[0043] Advantageously, the control system operates to choose an operating mode of the thermal management system of the vehicle to precondition the battery ready for charging in response to an indication received prior to arrival at a charging location that the fraction battery is to be charged. In particular, the method determines an energy costs associated with each of a plurality of operating modes of the thermal management system that are able to provide the thermal energy required to precondition the battery to the desired temperature and selects an operating mode that is expected to be the most efficient, i.e. the operating mode of the considered operating modes having the lowest energy cost, which may lead to improved overall efficiency for the electric vehicle.

[0044] According to an embodiment, the control system for controlling a thermal management system comprises one or more controllers collectively comprising at least one electronic processor having an electrical input for receiving an input signal; and at least one memory device electrically coupled to the at least one electronic processor and having instructions stored therein; and wherein the at least one electronic processor is configured to access the at least one memory device and execute the instructions thereon so as to perform any of the methods as described herein.

[0045] Optionally, the indication comprises an expected charging rate associated with the charging procedure, wherein the one or more processors are further configured to determine the target temperature based on the expected charging rate. In embodiments, the one or more processors are further configured to obtain information representative of the thermal energy transfer requirement by receiving a temperature signal indicative of a temperature of the traction battery, and determining, based on the temperature signal, the thermal energy transfer requirement of the traction battery, the energy transfer requirement representative of an amount of thermal energy to be transferred to or extracted from the traction battery to obtain the target battery temperature for the charging procedure.

[0046] In embodiments, the indication further comprises route information indicative of a predicted route of the vehicle to arrive at a charging location, and wherein the one or more processors are further configured to predict a future operating profile for the electric vehicle based on the route information, and determine the energy cost associated with each operating mode further based on the future operating profile.

[0047] According to an aspect of the present invention there is provided a vehicle comprising a thermal management system, and a control system as described herein coupled to the thermal management system.

[0048] Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and / or features of any embodiment can be combined in any way and / or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and / or incorporate any feature of any other claim although not originally claimed in that manner.

[0049] BRIEF DESCRIPTION OF THE DRAWINGS

[0050] One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0051] Figure 1 shows a system suitable for implementing embodiments of the invention;

[0052] Figure 2 illustrates a vehicle including the system of Figure 1 and suitable for implementing embodiments of the invention;

[0053] Figure 3 illustrates a schematic representation of a powertrain thermal management system suitable for implementing embodiments of the invention;

[0054] Figures 4A to 4F illustrate example configurations of the powertrain thermal management system of Figure 3 in accordance with embodiments of the invention;

[0055] Figure 5 illustrates a method of selecting an operating mode of a vehicle thermal management system according to embodiments of the invention; and

[0056] Figure 6 illustrates a control system suitable for performing the method of Figure 5, according to embodiments of the invention.

[0057] DETAILED DESCRIPTION

[0058] According to embodiments of the invention, a control system may select an operating mode of a thermal management system to precondition a fraction battery of an electric vehicle, such as a battery electric vehicle (BEV), or plug-in hybrid electric vehicle (PHEV), for charging. In response to receiving an indication that a charging procedure of the fraction battery is to be performed, an operating mode for the thermal management system can be selected that will transfer an amount of thermal energy to / from the traction battery such that the traction battery obtains a target battery temperature appropriate for the charging procedure. An energy cost associated with each of a plurality of possible operating modes of the thermal management system can be determined and the operating mode having the lowest determined energy cost selected. As the energy cost of operating the thermal management system is supplied by the traction battery, selecting a lowest cost operating mode may reduce the amount of electrical charge drawn from the fraction battery to precondition the fraction battery for charging, reducing the amount of charge that is to be replaced during the charging procedure, thereby reducing the time taken to charge the electric vehicle.

[0059] The selected operating mode may then be provided as an output signal indicating an operating mode of the thermal management system to precondition the fraction battery ready for charging. The indication that the charging procedure is to be performed may be received a period of time in advance of the charging procedure being initiated, for example the indication may be received from a satellite navigation system of the vehicle in response to a user setting a charging location as a destination. The indication may further include predicted routing information, or an expected time to destination, and an operating mode can be selected to operate the thermal management system while the vehicle is being driven to the charging location so as to obtain the target temperature for charging the fraction battery on arrival at the charging location, eliminating, or at least reducing, an amount of time a user must wait on arrival at the charging location before the charging procedure can begin.

[0060] By taking a whole system energy based approach for operating the thermal management system of the vehicle while meeting the predicted thermal requirements of the fraction battery to achieve the target temperature, the amount of thermal energy retained on the vehicle may be maximised, or at least substantially increased. This increase in retained thermal energy may reduce the amount of energy that would otherwise be drawn from the fraction battery, increasing efficiency with which energy is used on the electric vehicle, resulting in reduced charging times and a corresponding improved user experience.

[0061] With reference to Figure 1 , there is illustrated a vehicle thermal management system 100 for an electric vehicle in accordance with an embodiment of the present invention. The vehicle thermal management system 100 includes at least one controller 106 that is communicatively coupled to a powertrain thermal management system (PTM) 102 and a climate control system (CCS) 104 that comprises a heating, ventilation and air conditioning (HVAC) system, to receive state information and / or sensor readings from one or more components of the PTM 102 and HVAC, e.g. coolant or refrigerant temperature and mass flow rate measurements.

[0062] In embodiments, the controller 106 may be communicatively coupled to one or more components of the electric vehicle, for example via a Control Area Network (CAN) bus or similar network present on the vehicle 200, and is operable to obtain thermal energy information from the components. The thermal energy information defines a thermal energy transfer requirement for each of the components of the electric vehicle. The controller 106 is further arranged to provide indications of a selected operating mode to the PTM 102 and CCS 104 to influence the operation of those subsystems.

[0063] The vehicle thermal management system 100 as illustrated in Figure 1 comprises one controller 106, although it will be appreciated that this is merely illustrative. The controller 106 comprises processing means 108 and memory means 110. The processing means 108 may be one or more electronic processing device 108 which operably executes computer-readable instructions. The memory means 110 may be one or more memory device 110. The memory means 110 is electrically coupled to the processing means 108. The memory means 110 is configured to store instructions, and the processing means 108 is configured to access the memory means 110 and execute the instructions stored thereon.

[0064] In Figure 2, controller 106, PTM 102, and CCS 104 are provided in electric vehicle 200, such as an automobile. A powertrain of the vehicle 200 comprises at least one electric drive unit 202a / b and a traction battery 204. The or each electric drive unit 202a / b comprises one or more electric fraction motors for propelling the vehicle 200. The fraction battery 204 is a high voltage (HV) battery and is configured to supply electrical current to the at least one drive unit 202a / b. In the present embodiment, the vehicle 200 comprises a front electric drive unit 202a for driving the front wheels of the vehicle 200; and a rear electric drive unit 202b for driving the rear wheels of the vehicle 200. In use, the front and rear electric drive units 202a, 202b are both powered by the fraction battery 204. Each electric drive unit 202a / b may include power electronics, such as an inverter, to convert DC current sourced from the traction battery 204 to AC current to be supplied to the electric traction motors. As illustrated in Figure 1 , the PTM 102 is coupled to the CCS 104 of the cabin of the vehicle which is able to control a temperature of the vehicle cabin for occupant comfort.

[0065] While the traction battery 204, electric drive units 202a / b and HVAC may be the most significant generators and / or users of thermal energy supplied by the PTM 102, it will be recognized that other vehicle components may be coupled to the PTM 102 and may have thermal requirements to be met by the PTM. For example, in embodiments, the vehicle 200 may further include separate power electronics, such as an on-board AC charger, that may be significant generators of thermal energy while requiring cooling to maintain an operating temperature. Similarly, in embodiments, the electrical vehicle 200 may be provided with computer processing hardware that requires active cooling.

[0066] The components of the vehicle may have a target operating temperature range, or respective ranges, and operating the components outside of that range may lead to increased power consumption of the component or for the vehicle 200 as a whole. For example, when the temperature of the traction battery 204 increases, internal resistive losses within the traction battery 204 may also be expected to increase, while chemical reactions in the traction battery 204 may be inhibited when cold, similarly leading to increased losses in the battery. Such losses, when the powertrain components are not maintained within the desired operating temperature range, may result in reduced range for the vehicle 200.

[0067] In particular, the traction battery 204 has an associated target temperature range for performing a charging procedure of the battery. Prior to beginning the charging operation, preconditioning of the traction battery 204 may be performed to obtain the target battery temperature. The target temperature range may be dependent on a characteristic of the charging procedure to be performed, for example accurate temperature control of the traction battery 204 may be more important when charging at higher charge rates (e.g. greater than 50kW, greater than 150kW, etc.), while charging at relatively low charge rates (e.g. 3kW) may not require preconditioning of the battery. In some embodiments, the target charging temperature range and / or thermal energy transfer requirement of the traction battery may be dependent on an ambient temperature of the environment.

[0068] The vehicle thermal management system 100 is operable as a supply or sink of thermal energy to components of the vehicle 200, and in particular PTM 102 is thermally coupled to the traction battery 204 and electric drive units 202a / b and able to extract or supply thermal energy to these components to satisfy thermal energy transfer requirements of these components.

[0069] In an illustrative example of operation of the vehicle, thermal energy may be supplied via the PTM 102 to the traction battery 204 and electric drive units 202a / b when beginning operation of the vehicle 200 from cold to more quickly bring the components to the desired operating temperature range. During further operation of the vehicle 200, heat may be generated in the fraction battery 204 and electric drive units 202a / b, for example due to internal resistance of the cells of the traction battery 204. To maintain the temperature of the powertrain components within the desired temperature range, heat generated in the powertrain components of the vehicle 200 may be extracted by the PTM 102. The extracted thermal energy may be transferred between components of the vehicle 200, for example thermal energy extracted from the battery 204 may be supplied to CCS 104 for use in heating the cabin of the vehicle 200, or may be transferred off the vehicle 200, for example via a low temperature radiator to transfer the thermal energy to the outside environment.

[0070] The vehicle thermal management system 100 may be operable in a large number of different modes of operation to meet the various thermal transfer requirements of the components. Identifying an operating mode having a lowest, or at least reduced, energy cost for operation of the vehicle thermal management system 100 to meet the current thermal energy transfer requirements of the vehicle components may be difficult and may depend on a range of factors. Some of those factors may be external to the vehicle, such as an ambient temperature.

[0071] Furthermore, selecting an operating mode based only on a current state of the vehicle component may not allow changes in the generation of heat in the vehicle to be taken into account. For example, for an electric vehicle 200 being driven on a clear highway, the power supplied by the battery may be relatively high, leading to significant heat generation within the traction battery 204 due to internal resistance. At the same time, significant airflow may be expected over a low temperature radiator of the vehicle. An operating mode for the vehicle thermal management system 100 may be selected to extract heat generated within the traction battery 204 and reject that heat through the low temperature radiator to the environment, while providing a portion of the heat energy to the CCS 104 for cabin heating. The electric vehicle 200 may then slow, for example due to congestion on the highway or leaving the highway for a local road, resulting in reduced heat generation in the fraction battery 102 which may now be insufficient for cabin heating. In order to maintain a comfortable temperature for the cabin occupants, thermal energy may be supplied from another source, such as a heater drawing power from the traction battery 204, which undesirably uses power drawn from the fraction battery.

[0072] According to embodiments, the vehicle thermal management system 100 receives an indication that a charging procedure of the fraction battery is to be performed. The indication may be received a period of time in advance of the charging procedure being initiated or may include an indication of an expected or predicted arrival time at the charging location. For example, the indication may be received from a satellite navigation system of the electric vehicle 200 when a user requests routing to a charging location at which the vehicle will be charged. The indication may include a characteristic of the charging location, such as a charging rate provided at the charging location, the characteristic allowing a target temperature range for preconditioning the battery ready for charging to be determined. Based on a target battery temperature range for the charging procedure, a thermal energy transfer requirement for the traction battery 204 to obtain the target battery temperature may be determined, and an operating mode of the thermal management system 100 can be selected to satisfy the thermal energy transfer requirement. For each of a plurality of operating modes of the vehicle thermal management system 100, an associated energy cost for satisfying the thermal energy transfer requirement of the traction battery 204 is determined using a predictive model of the thermal management system 100. For example, a first operating mode may be selected for the vehicle thermal management system 100 that more thermal energy is retained on the vehicle 200, for example by allowing the temperature of the traction battery 204 to rise above its normal operating range, towards the target battery temperature range for charging, while the vehicle is driven to the charging location. While raising the temperature of the battery while driving may slightly reduce the efficiency of the traction battery 204, this may be offset by the thermal management system 100 avoiding a second operating mode that draws electrical power from the battery to power a heater to raise the temperature of the battery after arrival at the charging location, resulting in a lower energy cost associated with the first operating mode as compared to the second energy mode, and leading to improved efficiency for the vehicle overall.

[0073] Furthermore, the indication may include route information indicating a predicted route of the vehicle to reach at the charging location and the route information may be analysed to determine a predicted future operating profile for the vehicle 200 prior to arriving at the charging location. The future operating profile may include predicted speed, acceleration, elevation changes, etc. that are expected to occur as the vehicle travels to the charging location. Based on the future operating profile, heat generation in various components of the vehicle such as the traction battery 204 and electric drive units 202a / b can be predicted and used to predict thermal transfer requirements for the components of the electric vehicle for the duration of time taken to travel to the charging location. The determined energy costs associated with respective operating modes of the thermal management system 100 may then be determined based on these predicted thermal transfer requirements.

[0074] A schematic representation of an example PTM 102 is shown in Figure 3. A control valve apparatus 302 is configured to control the circulation of thermal transfer fluid, or coolant, to manage a thermal load of the front electric drive units 202a, the rear electric drive unit 202b, the battery unit 204 and the climate control system, or climate control unit 104 of the vehicle cabin for occupant comfort. The PTM 102 comprises a coolant heater 304; a first heat exchanger 306; and a second heat exchanger 308. The coolant heater 304 is configured to heat the coolant, for example to provide fast warm-up of traction battery 204 when initially operating the vehicle 200. The coolant heater 304 may be a high voltage (HV) heater that draws electrical power directly from fraction battery 204.

[0075] The first heat exchanger 306 may be configured selectively to cool the coolant of the PTM 102. A refrigerant circuit of the CCS 104 is coupled to a refrigerant side of the first heat exchanger 306 to cause the first heat exchanger 306 to operate as a chiller. Thus, the first heat exchanger 306 enables the transfer of heat energy extracted from the coolant to the refrigerant of the CCS 104. In this way, excess thermal energy may be transferred from powertrain components for use in heating the cabin of the vehicle. In some embodiments, the first heat exchanger 306 may be bi-directional and allow the transfer of thermal energy from the refrigerant of the CCS 104 to the coolant of the PTM 102, for example to allow for the supply heat sourced from the outside environment via an outside heat exchanger of the CCS 104 to heat the coolant. The refrigerant circuit may be coupled to an outside heat exchanger operable to transfer heat between the refrigerant and the outside environment. The supply of refrigerant can be halted to reduced or prevent heat exchange in the first heat exchanger 306. The second heat exchanger 308 is a low temperature heat exchanger (or a low temperature radiator) and is operative to reject heat from the coolant to the outside environment.

[0076] The control valve apparatus 302 comprises a first pump 310 and a second pump 312. The PTM 102 comprises a first coolant circulation loop 314; and a second coolant circulation loop 316. A liquid coolant, or thermal transfer fluid, is circulated through the first and second coolant circulation loops 314, 316 to perform supply or sinking of thermal energy to the front and rear electric drive units 202a, 202b and the fraction battery 204. At least one coolant temperature sensor 318 may be provided for measuring the temperature of the coolant. In the illustrated example, the coolant temperature sensor 318 is provided at an inlet to the second pump 312. The coolant temperature sensor 318 measures the temperature of the coolant supplied to the second pump 312. An electric fan (not shown) may optionally be provided to circulate air over the second heat exchanger 308 to promote cooling of the coolant.

[0077] The first coolant circulation loop 314 is configured to supply coolant to the traction battery 204. The coolant heater 304 and the first heat exchanger 306 are provided in the first coolant circulation loop 314. The coolant heater 304 is provided downstream of the traction battery 204 and, in use, is operative to heat the coolant. The first heat exchanger 306 is disposed upstream of the fraction battery 204 and, in use, can be configured to cool the coolant prior to introduction into the traction battery 204. As described herein, the first and second coolant circulation loops 314, 316 may be selectively connected to each other to enable the supply of coolant from the first heat exchanger 304 to the front and rear electric drive units 202a / b.

[0078] Bypass conduits may be provided for one or more components of the first 314 or second 316 coolant loops. A bypass conduit may controllably opened or closed by a valve to control the supply of coolant to the respective component. For example, the first coolant circulation loop 314 comprises a battery supply conduit 320, and a battery bypass conduit 322. The battery supply conduit 320 is configured to supply coolant to the fraction battery 204. The battery bypass conduit 322 can be selectively opened and closed to control the supply of coolant to perform cooling of the battery unit 204.

[0079] The second coolant circulation loop 316 is configured to supply coolant to the front and rear electric drive units 202a / b. The second heat exchanger 308 is provided in the second coolant circulation loop 316 downstream of the front and rear electric drive units 202a / b. In some examples, the front 202a and rear 202b electric drive units may each be provided with a respective bypass conduit (not shown) to selectively bypass the respective electric drive unit 202a, 202b, accordingly, transfer of thermal energy to or from the front 202a and rear 202b electric drive units may be permitted when the respective electric drive unit 202 is not bypassed and may be avoided when the respective electric drive unit 202 is bypassed.

[0080] In use, the second heat exchanger 308 rejects thermal energy from the coolant. The second coolant circulation loop 316 comprises a heat exchanger coolant conduit 324 for supplying coolant to the second heat exchanger 308; and a heat exchanger bypass conduit 326 for selectively bypassing the second heat exchanger 308. The control valve apparatus 302 may provide proportional control of the coolant flow rate through the heat exchanger bypass conduit 326, thereby controllably increasing or decreasing the flow through the second heat exchanger 308.

[0081] Control valve apparatus 302 includes crossflow valves 328 that are arranged to couple or decouple the first coolant circulation loop 314 (battery coolant circulation loop) and second coolant circulation loop 316 (electric drive unit coolant circulation loop). In addition, the crossflow valves 328 determine whether the first heat exchanger 306 is coupled in a coolant circulation loop with the battery 204 or the electric drive units 202. In other words, the crossflow valves 328 determine whether the first heat exchanger 306 is coupled in the first coolant circulation loop 314 or the second coolant circulation loop 316, or both when the first 314 and second 316 coolant circulation loops are coupled. The coupling and decoupling of the first coolant circulation loop 314, second coolant circulation loop 316 and first heat exchanger 306, as well as a state (on or off) of the first heat exchanger 306 defines the configuration of the PTM 102. When the first heat exchanger 306 is active, it couples the coolant circuit it is in with the refrigerant circuit.

[0082] Herein coupling between the first coolant circulation loop 314, second coolant circulation loop 316 and / or refrigerant circuit indicates that the first coolant circulation loop 314, second coolant circulation loop 316 and / or refrigerant circuit are in thermal communication, such that thermal energy may be transferred between them. Similarly, when they are decoupled, they are not in thermal communication, and no thermal energy (or a negligible amount of thermal energy) is transferred between them.

[0083] Thus, control valve apparatus 302 allows the configuration of the PTM 102 to be controlled to selectively bypass certain components of the thermal management system, such as the second heat exchanger 308, and / or to selectively couple the first and second coolant circulation loops 314, 316 together to allow transfer of thermal energy between the components served by the different coolant circulation loops. This means that there may exist a large number of possible configurations of the PTM 102. For each configuration, one or more components may be controlled to different states, for example first heat exchanger 306 may be on or off depending on whether refrigerant is provided to the first heat exchanger 306, second heat exchanger 308 may be selectively bypassed, etc. As such, there may be multiple operating modes of the PTM 102 for each of the configurations of the PTM, resulting in a large total number of possible operating modes for the PTM 102 from which an operating mode is to be selected by the controller 106 to meet current requirements of the various components of the electric vehicle 200. Each of the plurality of operating modes is associated with a configuration of at least two configurations of the thermal management system.

[0084] In embodiments, CCS 104 may include a refrigerant circuit including a compressor, at least one internal evaporator operable to extract heat energy from air in the cabin, at least one internal condenser operable to supply heat energy to the air in the cabin and an outside heat pump for exchanging thermal energy with an outside environment. As discussed above, refrigerant of the climate control system 104 may be selectively provided to first heat exchanger 306 to allow heat energy to be transferred between the coolant of the PTM 102 and the refrigerant of the CCS 104. Thus, CCS 104 may be operable in multiple modes. In some embodiments, selection of an operating mode for the CCS 104 may be coordinated with a selected operating mode for PTM 102 to further improve overall efficiency of the vehicle thermal management system 100.

[0085] The components of the vehicle may include one or more thermal customers. Each thermal customer may have a respective target operating temperature range, or a target operating temperature (for example where the upper and lower limits of the target operating temperature range may be considered to be the same). The thermal management system may be arranged to control temperatures of the thermal customers, e.g., to cause the thermal customers have respective temperatures that are in respective target operating temperature ranges. The traction battery 204; electric drive units 202; and vehicle cabin and / or CCS 104 are examples of thermal customers.

[0086] FIG. 4A to FIG. 4F show examples of configurations of the system of FIG. 3. Here, the first coolant circulation loop 314 includes the battery 204 and the coolant heater 304, the second coolant circulation loop 316 includes the electric drive units 202 and the second heat exchanger 308. The first coolant circulation loop 314 and second coolant circulation loop 316 may be selectively coupled or decoupled by the crossflow valves 328. Further the first heat exchanger 306 may be coupled with either of the first coolant circulation loop 314 or the second coolant circulation loop 316 (or both when the first coolant circulation loop 314 and the second coolant circulation loop 316 are coupled with each other) by the crossflow valves 328. As shown in FIG. 3, the valves 328 in the first and second coolant circulation loops 314, 316 may be arranged in multiple operational positions interconnecting their respective ports 1 -4 and 5-8. In FIGS. 4A-4F they have the following arrangements, as will become evident from the description below of the circulation loops resulting when the valves are so arranged:

[0087] FIGS. 4A and 4B: as shown in FIG. 3, with ports 1 and 3, 2 and 4, 5 and 7 and 6 and 8 being interconnected;

[0088] FIGS. 4C and 4D: different from FIG 3 and 4A, having ports 5 and 8 interconnected and ports 6 and 7 interconnected; and

[0089] FIG. 4E and 4F: as for FIGS. 4C and 4D, except ports 1 and 4 are interconnected, as are ports 2 and 3.

[0090] In FIG. 4A the first coolant circulation loop 314 and second coolant circulation loop 316 are decoupled, and the first heat exchanger 306 is in the first coolant circulation loop 314. The first heat exchanger 306 is not active, such that the first coolant circulation loop 314 is decoupled from the CCS 104 that comprises a refrigerant circuit 408. This leads to three thermal circuits being formed. The first thermal circuit 402a corresponds with the first coolant circulation loop 314 and includes the battery 204 and coolant heater 304. The second thermal circuit 402b corresponds with the second coolant circulation loop 316 and includes the electric drive units 202 and the second heat exchanger 308. The third thermal circuit 402c corresponds with the refrigerant circuit 408 and includes the internal evaporator 404 and the outside heat exchanger 406.

[0091] FIG. 4B shows the same configuration as FIG. 4A, with the first coolant circulation loop 314 and second coolant circulation loop 316 being decoupled and the first heat exchanger 306 being in the first coolant circulation loop 314. However, in FIG. 4B the first heat exchanger 306 is active, and so the first coolant circulation loop 314 is coupled with the refrigerant circuit 408. This leads to two thermal circuits. A first thermal circuit 402a includes battery 204, coolant heater 304, first heat exchanger 306, internal evaporator 404 and outside heat exchanger 406. The second thermal circuit 402b includes the electric drive units 202 and the second heat exchanger 308.

[0092] In FIG. 4C the first coolant circulation loop 314 and second coolant circulation loop 316 are coupled. The first heat exchanger 306 is also coupled in the first coolant circulation loop 314 and the second coolant circulation loop 316. The first heat exchanger 306 is not active, such that the first coolant circulation loop 314 and second coolant circulation loop 316 are decoupled from the refrigerant circuit 408. This leads to two thermal circuits being formed. The first thermal circuit 402a corresponds with the combined first coolant circulation loop 314 and second coolant circulation loop 316, and includes the battery 204, coolant heater 304, electric drive units 202, and second heat exchanger 308. The second thermal circuit 402b corresponds with refrigerant circuit 408.

[0093] FIG. 4D shows the same configuration as FIG. 4C, with the first coolant circulation loop 314 and second coolant circulation loop 316 being coupled. However, in FIG. 4D the first heat exchanger 306 is active, and so the first coolant circulation loop 314 and second coolant circulation loop 316 are coupled with the refrigerant circuit 408. This leads to an arrangement with one thermal circuit 402a that includes all of the illustrated components. In FIG. 4E the first coolant circulation loop 314 and second coolant circulation loop 316 are decoupled, as in FIG. 4A, but now the first heat exchanger 306 is in the second coolant circulation loop 316. The first heat exchanger 306 is not active, such that the second coolant circulation loop 316 is decoupled from the refrigerant circuit 408. This leads to three thermal circuits being formed. These thermal circuits are the same as in FIG. 4A, except that the first heat exchanger 306 is in the second coolant circulation loop 316. As such, the thermal transfer in this arrangement is the same or similar to the arrangement of FIG. 4A. However, these modes of operation are not necessarily equivalent. For example, an energy cost to transition to the mode of FIG. 4A may be less than the energy cost to transition to the mode of FIG. 4E, for example, and so the mode of FIG. 4A may be a better selection than the mode of FIG. 4E in that case. The energy cost of transitioning may be associated with driving actuators to control the crossflow valves 328, for example.

[0094] FIG. 4F shows the same configuration as FIG. 4E, with the first coolant circulation loop 314 and second coolant circulation loop 316 being decoupled and the first heat exchanger 306 being in the second coolant circulation loop 316. However, in FIG. 4F the first heat exchanger 306 is active, and so the second coolant circulation loop 316 is coupled with the refrigerant circuit 408. This leads to two thermal circuits. A first thermal circuit 402a includes battery 204 and coolant heater 304. The second thermal circuit 402b includes the electric drive units 202, the second heat exchanger 308, the first heat exchanger 306, the internal evaporator 404, and outside heat exchanger 406.

[0095] Arrangements, such as those shown in FIG. 3 and FIG. 4A to FIG. 4F, lead to a significant number of possible operating modes for the thermal management system 102. In each of the configurations, components such as the second heat exchanger 308, coolant heater 304 and outside heat exchanger 406 may each be active or inactive. In some examples the number of modes may exceed one hundred. In some examples, the number of modes may exceed two hundred.

[0096] Where a system is capable of fewer configurations, a smaller number of potential operating modes exist and there are fewer options for heat transfer among the components of a vehicle. In such systems, the selection of an operating mode may be straightforward, e.g., using a lookup table that indicates a mode based on temperatures of components of the vehicle (e.g. taking into account the temperatures of three or fewer components). However, the reduced options of transferring heat between components may limit the achievable energy efficiency.

[0097] In some systems that provide a range of configurations of the thermal management system that are comparable to the examples in FIG. 3 and FIG. 4A to FIG. 4F, the full benefit of these configurations may not be achieved where the system allows limited combinations of configurations with operation states of components (such as a heater on / off or radiator used / bypassed). In such systems, only a small subset of the potential modes are selectable. Similarly to the case of where few configurations are available, in such systems, a mode of the thermal system may be selected based on relative temperatures of the components according to a table of selectable modes. In such systems, the number of selectable modes may be fewer than 20 or fewer than 15, for example. Accordingly, these systems provide limited flexibility in controlling heat transfer between components, potentially losing opportunities for energy efficiency.

[0098] As noted above, in systems having a relatively small number of operating modes (e.g., 20 or fewer), an operating mode may be selected in a relatively straightforward way, e.g. from a table based on temperatures of the components. The table (or other mode selection method) may be defined in advance based on engineer intuition. Expanding such temperature-based approaches by considering heat availability or heat demand in specific components in the selection of particular modes does not address the limitations of a system with few selectable operating modes, and does not take efficiency of the operating modes into consideration when selecting an operating mode.

[0099] Where the number of operating modes significantly increases, a selection of a mode based on engineer intuition becomes impractical, and reliably selecting an appropriate operating mode becomes increasingly difficult using a simple table-based, or similar, approach.

[0100] According to examples herein, energy costs associated with different operating modes are determined and used in the selection of an operating mode to be implemented. This may allow for more reliable selection of an energy efficient operating mode. Moreover, the selection of the operating mode may better take into account the current state of the components of the vehicle compared with temperature-based or table-based approach.

[0101] Figure 5 illustrates a method 500 of determining an operating mode of a thermal management system of an electric vehicle to precondition a traction battery for charging. The method may be applied for the vehicle thermal management system 100, of an electric vehicle 200 and may be performed by the controller 106 illustrated in Figure 1 . According to the illustrated method 500, an indication is received 502, to indicate that a charging procedure of the traction battery 204 is to be performed. The indication may be received a period of time in advance of the charging procedure being initiated or may include a predicted route to, or an indication of an expected arrival time at, the charging location. For example, the indication may be received from a satellite navigation system of the electric vehicle 200 when a user requests routing to a charging location at which the vehicle will be charged, or may be generated in response to an infotainment system of the vehicle warning the user of a low charge level of the traction battery and directing the user to a charging location.

[0102] Where provided, route information may include a road characteristic, such as type of road, traffic data indicating a level of traffic, congestion, etc. that may be experienced along a predicted route. Furthermore, route information may include gradient or elevation data.

[0103] Thermal energy information for a traction battery 204 of the electric vehicle 200 is obtained 504, the thermal energy information defining a thermal energy transfer requirement representative of an amount of thermal energy to be transferred between the traction battery and the vehicle thermal management system 100 to obtain a target battery temperature for charging the traction battery 204.

[0104] The thermal energy transfer requirement may include one or more of an amount of thermal energy transfer requested by the traction battery, and a rate of transfer of thermal energy requested by the traction battery. Accordingly, the thermal energy transfer requirement for the traction battery may include at least one of: an indication of a rate of thermal energy to be supplied, a rate of thermal energy to be extracted, an indication of an amount of thermal energy to be supplied, or an indication of an amount of thermal energy to be extracted. In some examples the target thermal energy transfer rate of the traction battery may be determined based on a current temperature of the traction battery and a target battery charging temperature range of the traction battery. In some examples the target thermal energy transfer rate may be based on a model of the traction battery In some examples, the target thermal energy transfer rate may be obtained from a lookup table. In some examples the thermal energy transfer requirement for the traction battery may be based on a difference between a current temperature of the traction battery and the target battery temperature.

[0105] Where a traction battery has a target charging temperature range, the target charging temperature of the traction battery may be a high temperature point or a low temperature point of a target charging temperature range of the traction battery. The target charging temperature may be whichever of the high temperature point or the low temperature point of a target charging temperature range is closest to a current temperature of the traction battery.

[0106] Where the thermal energy transfer requirements indicate amounts of thermal energy to be transferred, a thermal energy transfer requirement may indicate an amount of thermal energy to be provided to or removed from the traction battery to bring the traction battery within its target charging temperature range.

[0107] Information defining a plurality of operating modes of the thermal management system is obtained in block 506. The plurality of operating modes defined by the obtained information are a subset of the total number of operating modes of the vehicle thermal management system 100 that are able to satisfy the thermal energy transfer requirement of the traction battery 204. For example, if the obtained thermal energy information indicates that the traction battery requires an amount of thermal energy to be transferred away from the battery to obtain the target charging temperature, only those operating modes capable of extracting heat energy from the fraction battery 204 may be defined in the information obtained in block 506. For each operating mode of the operating modes defined in block 506, an energy cost value is determined 508 for operating the vehicle thermal energy system 100 in that operating mode. In embodiments, the energy cost value may represent an actuator energy cost associated with the operation of the vehicle thermal management system 100 and also an amount of thermal energy to be transferred off the electric vehicle 200 in that operating mode. The energy cost for each operating mode may be determined using a predictive model of the vehicle thermal management system 100 and / or of the PTM 102 and CCS 104.

[0108] Heat energy may be transferred off the vehicle via the second heat exchanger 308, or low temperature radiator, or by transferring heat to the refrigerant circuit of the climate control system 104 via the first heat exchanger 306 and then to the outside environment via the outside heat exchanger of the refrigerant circuit. The total amount of heat transferred off the electric vehicle 200 using the thermal management system 102 may be determined to calculate the thermal energy transferred off the electric vehicle 200. The actuator energy cost may include any energy associated with operating the vehicle thermal management system, including the PTM 102 and the CCS 104, for example an energy cost required to operate the compressor of the refrigerant circuit to provide refrigerant to the first heat exchanger 306, or a vehicle drag cost associated with opening vanes to provide airflow to an outside heat exchanger of the refrigerant circuit. Examples of actuator energy costs associated with an operating mode may include: an energy cost of operating a compressor according to that operating mode; a valve actuation energy cost associated with that operating mode; a vehicle drag cost associated with operation of a heat exchanger according to that operating mode; an energy cost of operating a pump according to that operating mode; and an energy costs of operating a fan according to that operating mode. Certain actuators in the thermal management system 102, for example pumps, compressors, fans, etc., may have an associated duty cycle or activation level setting to satisfy the thermal energy transfer requirements of the components when the thermal management system is operating in a particular operating mode. Energy costs for actuators may be further calculated based on the duty cycle to provide a more accurate determination of the energy associated with operating the actuator.

[0109] As discussed above, the energy cost for each operating mode is determined using a predictive model of the vehicle thermal management system 100. In embodiments, the predictive model of the thermal management system may comprise a plurality of predictive models each associated with a respective sub-component of the vehicle thermal management system. Thus, each actuator energy cost may be calculated using a model of the respective actuator that defines a relationship between one or more operating parameters of the vehicle thermal management system and an energy cost associated with the actuator. For example, a predictive model for the compressor of the refrigerant circuit may allow an energy cost of operating the compressor to be determined based on certain operating parameters, such as the duty cycle of the compressor. Each model may be determined empirically or through simulation of the PTM 102 and CCS 104. In some embodiments, a model for each actuator may be stored as a look up table (LUT) associating one or more operating parameters of the actuator with an associated actuator energy cost.

[0110] Similarly, predictive models may be provided for the first and second heat exchangers and for an outside heat exchanger of the refrigerant circuit to allow the thermal energy to be transferred off the vehicle to the outside environment to be determined based on one or more measured parameters. For example, heat rejected to the outside environment by the second heat exchanger 308 may be predicted based on one or more of: an ambient temperature of the outside environment; a flow rate and / or temperature of coolant through the second heat exchanger 308; an operating state of a fan associated with the second heat exchanger 308, etc.

[0111] In embodiments, the actuator energy cost for an operating mode may be determined by summing all of the actuator energy costs associated with operating the vehicle thermal management system 100 in that operating mode to meet the thermal transfer requirements of the components. The energy cost associated with the operating mode may then be calculated by summing the actuator energy cost with the total amount of thermal energy transferred off the vehicle via the second heat exchanger 208 and the outside heat exchanger of the refrigerant circuit.

[0112] Based on the calculated energy costs for each of the plurality of operating modes, the operating mode having the lowest determined energy cost is selected at block 510. An output including an indication of the selected operating mode is then provided 512.

[0113] Where route information is provided, a future operating profile for the electric vehicle 200 to arrive at the charging location may be predicted. The future operating profile may include indications of predicted velocities of the vehicle, whether the vehicle may be expected to brake for a junction, changes in elevation, etc. relating to operation of the vehicle while traversing the predicted route. This information may be used to predict heat generation in one or more components of the electric vehicle 200 while the vehicle traverses the route. This may be based on a predictive model of the component that can be used to predict an amount of thermal energy, or rate of heat energy, generated in a component according to the expected future operating profile of the vehicle.

[0114] For example, the future operating profile may be used to predict an amount and / or rate of electrical energy (i.e. electrical power) to be supplied from the traction battery 204 while the vehicle traverses the predicted route with an expected speed profile, allowing for elevation changes, etc. A predictive model of the traction battery 204 can then be used to predict the heat energy that will be generated in the traction battery 204, e.g. due to resistive heating while supplying the required electrical energy, and a thermal transfer requirement for the traction battery 204 indicating an amount of thermal energy to be transferred to or from the battery 204 to obtain the target charging temperature range on arrival at the charging location can be determined. Similarly, heat generation in other components, such as electric drive units 202a / b, may be predicted based on the expected future operating profile, such as predicted power output, and corresponding predicted thermal energy transfer requirements for those components determined. In some operating modes of the vehicle thermal management system 100, thermal energy may be transferred between other components of the electric vehicle 200 and the traction battery 204 to meet the thermal energy transfer requirement of the traction battery 204. For example, heat generated in the electric drive units 202a / b may be transferred to the traction battery 204 to raise the temperature of the traction battery 204 to the target charging temperature range.

[0115] The predicted thermal energy transfer requirement for a component may indicate that thermal energy is to be supplied to the component or extracted from the component. The thermal energy information may indicate an amount of thermal energy, for example a number of Joules, to be transferred to or from that component to change its temperature to a desired operating range. In some embodiments, the thermal energy transfer requirement may indicate a rate, or flux, of thermal energy (i.e. a number of Watts of thermal energy transfer) to be transferred to / from the component. In embodiments, the thermal energy transfer requirement may be determined based on a temperature difference between a current temperature of the component and a desired temperature range combined with a heat capacity of the component. The heat capacity of the component may be determined empirically or calculated based on a specific heat capacity of the material of the component and a mass. In the case that the temperature of the component is already within the desired temperature range, the thermal energy information may provide an indication that thermal energy may be transferred to or extracted from the component. For example, a component, such as the traction battery 204, that is predicted to be within a target temperature range may be used as a source of thermal energy that may be transferred by the vehicle thermal management system 100 to another component e.g. to avoid use of the heater for as long as the fraction battery 204 is able to supply heat energy while remaining within the desired temperature range.

[0116] In embodiments, the method may further include obtaining current thermal energy information for the one or more components defining a current state of the component, e.g. a current temperature or thermal energy transfer requirement of the component. The current thermal energy information may be used to determine the predicted thermal energy requirement, e.g. in the case that the fraction battery 204 is currently operating below an associated target charging temperature range, the predicted thermal energy transfer requirement for the fraction battery may be determined to allow an amount of heat energy generated in the fraction battery to be retained within the fraction battery to cause the temperature of the battery to rise to the target charging temperature range.

[0117] Thus, the method 500 is able to identify which of the operating modes of the vehicle thermal management system 100 is able to most efficiently meet the predicted thermal transfer requirements of the traction battery 204 to obtain the target charging temperature (or target charging temperature range), leading to reduced energy drawn from the fraction battery prior to charging which would otherwise need to be replaced by increasing the time for which the fraction battery is charged.

[0118] In embodiments, the thermal energy transfer requirement of the traction battery may be predicted for a defined period of time, for example a predefined number of minutes or the predicted travel time to arrive at the charging location. The energy cost associated with each operating mode may be calculated for the defined period of time, allowing for dynamic effects such as predicted changes in the operating regime of the vehicle (e.g. highway driving; around town; parked) to be taken into account when selecting a lowest energy cost operating mode for the vehicle thermal management system 100. Certain methods and systems as described herein may be implemented by one or more processors that process program code that is retrieved from a non-fransitory storage medium. Figure 6 shows an example 600 of a device comprising a computer- readable storage medium 620 coupled to at least one processor 610. The computer-readable media 620 can be any media that can contain, store, or maintain programs and data for use by or in connection with an instruction execution system. Computer-readable media can comprise any one of many physical media such as, for example, electronic, magnetic, optical, electromagnetic, or semiconductor media. More specific examples of suitable machine-readable media include, but are not limited to, a hard drive, a random-access memory (RAM) , a read-only memory (ROM), an erasable programmable read-only memory, or a portable disc. In Figure 6, the computer-readable storage medium comprises program code to perform a method corresponding to the embodiment shown in Figure 5, that is: receiving 502 an indication that a charging procedure of a traction battery of the electric vehicle is to be performed; obtaining 504 information representative of a thermal energy transfer requirement for the traction battery to obtain a target battery temperature for charging of the fraction battery; obtaining 506 information defining a plurality of operating modes of the thermal management system, each of the plurality of operating modes operable to satisfy the thermal energy transfer requirement; determining 508, for each operating mode of the plurality of operating modes, an energy cost associated with that operating mode using a model of the thermal management system; selecting 510 an operating mode having a lowest determined associated energy cost; and providing 512 an output indicating the selected operating mode. It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Claims

CLAIMS1 . A method of determining an operating mode of a thermal management system of an electric vehicle, the operating mode being to precondition a traction battery for charging, the method comprising: receiving an indication that a charging procedure of the traction battery of the electric vehicle is to be performed; obtaining information representative of a thermal energy transfer requirement for the traction battery, the thermal energy transfer requirement representative of an amount of thermal energy to be transferred between the traction battery and the thermal management system to obtain a target battery temperature for charging of the traction battery; obtaining information defining a plurality of operating modes of the thermal management system, each of the plurality of operating modes operable to satisfy the thermal energy transfer requirement; determining, for each operating mode of the plurality of operating modes, an energy cost associated with that operating mode using a model of the thermal management system; selecting an operating mode having a lowest determined associated energy cost; and providing an output indicating the selected operating mode.

2. The method of claim 1 , wherein the indication comprises a characteristic associated with the charging procedure, the method further comprising determining the target temperature based on the characteristic.

3. The method of claim 1 or claim 2 , wherein the electric vehicle comprises a plurality of components thermally coupled to the thermal management system; and at least one operating mode of the plurality of operating modes is operable to transfer thermal energy between at least one of the plurality of components and the traction battery.

4. The method of claim 3, wherein the plurality of components comprise at least one of: an electric drive unit; a heater; a heat pump; and a cabin air conditioning unit.

5. The method of any preceding claim, wherein obtaining information representative of the thermal energy requirement for the traction battery further comprises: receiving a temperature signal indicative of a temperature of the traction battery; and determining, based on the temperature signal, the thermal energy transfer requirement of the traction battery, the energy transfer requirement being representative of an amount of thermal energy to be transferred to or extracted from the traction battery to obtain the target battery temperature for the charging procedure.

6. The method of claim 5, further comprising: receiving an ambient temperature value indicative of an ambient temperature of the environment; wherein the thermal energy transfer requirement for the traction battery is further determined based on the ambient temperature value.

7. The method of any preceding claim, wherein the indication further comprises route information indicative of a predicted route of the vehicle to arrive at a charging location, the method further comprising: predicting a future operating profile for the electric vehicle based on the route information; and determining the energy cost associated with each operating mode further based on the future operating profile.

8. The method of claim 7, further comprising: determining a thermal energy value indicative of an amount of thermal energy that will be generated in the fraction battery based on the future operating profile; and wherein obtaining information representative of the thermal energy requirement for the traction battery further comprises determining, based on the determined thermal energy value, the thermal energy transfer requirement of the traction battery, the energy transferrequirement being representative of an amount of thermal energy to be transferred to or extracted from the traction battery to obtain the target battery temperature for the charging procedure.

9. The method of claim 7 or claim 8, further comprising: predicting for at least one further component of the electric vehicle, a thermal energy transfer requirement for the at least one further component based on the expected future operating profile; and wherein determining, for each operating mode of the plurality of operating modes, the energy cost associated with that operating mode is further based on the determined thermal energy transfer requirement for the at least one further component.

10. Computer readable instructions which, when executed by one or more processors, cause the one or more processors to perform the method according to any of claims 1 to 9.

11. A control system for controlling a thermal management system of a vehicle, the control system comprising one or more processors collectively configured to: receive an indication that a charging procedure of a traction battery of the electric vehicle is to be performed; obtain information representative of a thermal energy transfer requirement for the traction battery, the thermal energy transfer requirement representative of an amount of thermal energy to be transferred between the fraction battery and the thermal management system to obtain a target battery temperature for charging of the fraction battery; obtain information defining a plurality of operating modes of the thermal management system, each of the plurality of operating modes operable to satisfy the thermal energy transfer requirement; determine, for each operating mode of the plurality of operating modes, an energy cost associated with that operating mode using a model of the thermal management system; select an operating mode having a lowest determined associated energy cost; and provide an output indicating the selected operating mode.

12. The control system of claim 11 , wherein the indication comprises an expected charging rate associated with the charging procedure, wherein the one or more processors are further configured to determine the target temperature based on the expected charging rate.

13. The control system of claim 11 or claim 12, wherein the one or more processors are further configured to obtain information representative of the thermal energy transfer requirement by: receiving a temperature signal indicative of a temperature of the fraction battery; and determining, based on the temperature signal, the thermal energy transfer requirement of the traction battery, the energy transfer requirement representative of an amount of thermal energy to be transferred to or extracted from the fraction battery to obtain the target battery temperature for the charging procedure.

14. The control system of claim 11 or claim 12, wherein the indication further comprises route information indicative of a predicted route of the electric vehicle to arrive at a charging location, and wherein the one or more processors are further configured to: predict a future operating profile for the electric vehicle based on the route information; and determine the energy cost associated with each operating mode further based on the future operating profile.

15. A vehicle comprising: the control system of any of claims 11 to 14; and a thermal management system communicatively coupled to the control system.

Images