BATTERY HEAT MANAGEMENT

Abstract

A method (400) for managing the thermal energy of a battery (38) in a vehicle (10) with an electric drive system, comprising: Monitoring the current battery temperature after the vehicle (10) has been connected to an external power source (39) at a connection time (312, 342, 372); Determining (416) an outside air temperature (172); Predictions (418) of a cabin heating temperature for a subsequent driving cycle, wherein the subsequent driving cycle takes place when the vehicle (10) is no longer connected to the external power source (39); If the predicted cabin heating temperature is greater than the outside air temperature (172), the battery (38) is heated to a heat storage temperature (348) that is greater than a target operating temperature of the battery (38), so that heat energy is stored in the battery (38); Prediction of a journey start time (325), wherein the journey start time (325) occurs after the vehicle (10) has been disconnected from the external power source (39); Determining a charging time between a charging start and a charging end (314) during which the battery (38) reaches a substantially full state of charge; If the journey start time (325) is later than the charging time, delay the start of charging until after the connection time (312, 342, 372); Starting the charging process so that the charging time is at least 80% of the time elapsed before the predicted trip start time (325); and Transferring the heat energy stored in the battery (38) to a cabin of the vehicle (10) after the journey has started (325).

Description

INTRODUCTION

[0001] The present disclosure relates to thermal management of batteries in electric vehicles. Example vehicles include electric or plug-in hybrid vehicles.

[0002] DE 10 2014 204 260 A1 describes an electric vehicle having a thermal circuit connected to a traction battery and a cabin climate control system, a user interface, and a controller. The controller is configured to charge the traction battery to a target state of charge, condition the traction battery to a target battery temperature, and condition a vehicle cabin to a target cabin temperature based on a charge profile generated by the user input in response to receiving a user input requesting vehicle conditioning via the user interface, wherein the traction battery is connected to an external power source.A method for controlling an electric vehicle connected to an external power source includes charging a traction battery to a target state of charge and conditioning the battery to a target battery temperature according to a charging profile based on a user-initiated vehicle conditioning request. DESCRIPTION

[0003] The invention is defined by the claims.

[0004] A system and method for managing the thermal energy of a vehicle having a battery and an electric propulsion system are provided. The system monitors a current battery temperature after the vehicle is connected to an external power source at a connection time and determines an outside air temperature.

[0005] The system predicts a cabin heating temperature for a subsequent drive cycle. The subsequent drive cycle occurs when the vehicle is no longer connected to the external power source. If the predicted cabin heating temperature is higher than the outside air temperature, the system heats the battery to a thermal storage temperature that is higher than the battery's target operating temperature. Therefore, thermal energy is stored in the battery.

[0006] Generally, heating the battery to the thermal storage temperature occurs while the battery is charging from the external power source. Furthermore, heating may only occur if both the thermal storage temperature and the cabin heating temperature are higher than the outside air temperature. The system can then transfer the thermal energy stored in the battery to a vehicle cabin, so that the cabin is heated by thermal energy from the battery. Heating to the thermal storage temperature can occur before a trip start time, which occurs after the vehicle is disconnected from the external power source.

[0007] The system or method can predict a trip start time that occurs after the vehicle is disconnected from the external power source and can determine a charging duration between a charging start and a charging end time at which the battery has reached a sufficiently full state of charge. Then, if the trip start time is later than the charging duration, the system delays the start of charging until after the connection time and begins charging such that the charging duration is at least 80% of the time before the predicted trip start time.

[0008] The charging time can be calculated to include a base charging time, during which the battery is brought to a target state of charge, and a heating time to a minimum charging temperature, during which the battery is heated to a minimum charging temperature. The charging time can also be calculated to include a conditioning time, during which the battery is heated by a resistance heater or heat pump. These elements can be included in the calculation of the charging time, the charging time, or the recharging time.

[0009] In some configurations, the system can generate heat energy using a resistive heater or heat pump while the vehicle is still connected to the external power source. The system can then circulate the generated heat energy to the battery, so that the battery's thermal storage temperature is higher than a natural charging temperature that would have resulted from charging alone.

[0010] The above features and advantages, as well as other features and advantages of the present disclosure, are readily apparent from the following detailed description of the preferred embodiments of the disclosure when considered in conjunction with the accompanying figures. BRIEF DESCRIPTION OF THE CHARACTERS Fig. 1 is a schematic environmental view of a motor vehicle with an electric drive system, such as a hybrid electric vehicle or a battery electric vehicle. Fig. 2 is a schematic system diagram illustrating a thermal management system for a motor vehicle such as that shown in Fig. 1. Fig. Figure 3 is a first schematic valve diagram showing opening and closing states for a plurality of valves within a thermal management system such as that shown in Fig. 2 shown. Fig. 4 is a schematic second valve diagram showing opening and closing states for a valve within a thermal management system such as that shown in Fig. 2 shown. Fig. 5A-D are schematic diagrams illustrating example thermal management strategies for selectively cooling a battery to extend driving range and durability, where: Fig. 5A shows the active battery cooling during or after driving; Fig. Figure 5B shows delayed or non-cooling based on the actual average battery temperature over the lifetime; Fig. Figure 5C shows two examples of active battery cooling during driving based on differences between the target and actual average battery temperature over the lifetime; and Fig. 5D early battery cooling based on a predicted driving cycle where battery temperature is likely to increase in the future. Fig. Figure 6 shows an illustrative flowchart for a process for implementing a learned battery cooling strategy. Fig. 7A-C are schematic diagrams illustrating example thermal management strategies for selectively heating a battery during preconditioning to extend subsequent driving range, where: Fig. Figure 7A shows the heat energy supplied to the battery after charging; Fig. 7B shows the adjusted start time of the charging cycle so that heat energy is selectively stored in the battery; and Fig. 7C shows the heat energy supplied to the battery during charging. Fig. 8 shows an illustrative flow diagram for a method for using a battery as a thermal energy storage device for cabin heating. DETAILED DESCRIPTION

[0011] With reference to the drawings, similar reference numerals refer to similar components wherever possible. Fig. 1 schematically shows a top view of a motor vehicle 10. While the vehicle 10 is depicted as a car, it should be understood that the vehicle 10 may be a car, a truck, an SUV, a van, a semi-trailer, a tractor, a bus, a go-kart, or any other rolling platform without departing from the scope or intent of the present disclosure. The vehicle 10 is equipped with a thermal management system 12.

[0012] Also with reference to Fig. 2, a schematic diagram of the thermal management system 12 is shown. Generally, the thermal management system 12 operates to selectively transport thermal energy from a heat source within the thermal management system 12 to a heat sink within the thermal management system 12, or from a heat source or a heat sink to a location within the thermal management system 12 where the thermal energy could be needed or utilized to enhance the function of the vehicle 10.

[0013] The thermal management system 12 includes a plurality of different thermal fluid circuits 14 for various subsystems of the vehicle 10. Each of the different thermal fluid circuits 14 has heat sources and heat sinks connected to one or more subsystems of the vehicle 10. Some heat sinks are significantly more massive and therefore capable of storing more thermal energy than others. Accordingly, depending on the thermal energy storage capacities of various heat sinks within the thermal management system 12, thermal energy can be moved from one of the different thermal fluid circuits 14 to another.

[0014] While the disclosure may be illustrated with respect to particular applications or fields, those skilled in the art will recognize the broader applicability of the disclosure. Those skilled in the art will recognize that terms such as "over," "under," "above," and "below" are used descriptively for the figures and do not represent limitations on the scope of the disclosure as defined by the appended claims. Any numerical designations such as "first" or "second" are illustrative only and are not intended to limit the scope of the disclosure in any way.

[0015] Features illustrated in one figure may be combined with, replaced by, or modified by features illustrated in any of the illustrations. Unless otherwise noted, no features, elements, or limitations are mutually exclusive with any other features, elements, or limitations. Furthermore, no features, elements, or limitations are essential to operation. Any specific configurations shown in the figures are for illustrative purposes only, and the specific configurations shown do not constitute limitations on the claims or the description.

[0016] The term "substantially" as used herein refers to relationships that are ideally perfectly or completely satisfied, but where manufacturing circumstances prevent absolute perfection. Substantially, therefore, refers to the typical deviation from perfection. For example, if height A is substantially equal to height B, it may be preferable for the two heights to be 100.0% equal, but manufacturing circumstances are likely to cause the distances to deviate from this perfection. Those skilled in the art would recognize the extent of acceptable deviation. For example, and without limitation, coverages, areas, or distances can generally be substantially equal to within 10% of perfection. Similarly, relative alignments, such as parallel or perpendicular, can generally be considered to be within 5%.

[0017] The vehicle 10 can circulate or transfer thermal energy through a reduced number of thermal fluid circuits 14 compared to other approaches. Fig. 1 and Fig. 2, the vehicle 10 circulates the thermal energy generated on board the vehicle only through the three thermal fluid circuits 14. In other words, the thermal requirements of the vehicle 10, i.e., any need to heat or cool parts of the vehicle 10, as well as to heat or cool the passenger compartment, can be met with only the three thermal fluid circuits 14. Thermal energy can be transferred through the thermal fluid circuits 14 by conduction, convection, or any other heat transfer mechanism. As used herein, cooling refers to reducing the current temperature of the referenced component or system, and heating refers to increasing the temperature of the referenced component or system.

[0018] A control system or controller 16 communicates with a plurality of actuators, valves, and the like and manages the operation of the thermal management system 12, including the plurality of different thermal fluid circuits 14. The controller 16 is a non-generalized, electronic control device having a pre-programmed digital computer or processor 18, a memory or non-transitory computer-readable medium 20 used to store data such as control logic, instructions, lookup tables, etc., and a plurality of input / output peripherals or ports 22. The processor 18 is configured to execute the control logic or instructions described herein.

[0019] The controller 16 may include additional processors or additional integrated circuits in communication with the processor 18, such as logic circuits for analyzing thermal management data. In some examples, the controller 16 may be comprised of a plurality of controllers 16, each designed to interact with and manage specific assemblies within the vehicle 10, and each of the plurality of controllers 16 is in electronic communication with the others. While more than one controller 16 may be used in some examples, for clarity, the following description describes the thermal management system 12 as including only one controller 16. The controller 16 may be dedicated to the thermal management system 12 or may be part of a larger control system or other functions of the vehicle 10.

[0020] With reference to the two Fig. 1 and Fig. 2, a first of the various thermal fluid circuits 14 is a coolant circuit 24. The coolant circuit 24 includes a coolant pump 26 that selectively pumps cooling fluid 28 through a plurality of coolant lines 32. The coolant lines 32 are in fluid communication with a plurality of components of the coolant circuit 24. In some aspects, the cooling circuit 24 includes an integrated power electronics (IPE) module 34. The IPE 34 is an electronic device including a variety of apparatus usable by an operator of the vehicle 10.

[0021] In some cases, the IPE 34 includes one or more of an AC / DC converter (not shown), a high-voltage power supply (not shown), a navigation system (not shown), a high-voltage charger (not shown), a seat heating system (not shown), and / or other similar devices and functions. While the IPE 34 is operating, the electronics within the IPE 34 convert electrical energy into a variety of functions that can be utilized by the operator. Additionally, heat energy is generated as a byproduct of the use of electrical energy within the IPE 34 devices. The cooling fluid 28 carries the heat energy from the IPE 34 devices to other locations in the coolant circuit 24.

[0022] The coolant circuit 24 further includes an onboard charging module (OBCM) 36 for a battery 38. The OBCM 36 is an electrical device configured to supply energy to a secondary cell or battery 38 by forcing an electrical current through the battery 38. In some examples, a single-phase 3.5 kW to 22 kW OBCM 36 is installed within the electrical system of the vehicle 10 and charges the vehicle 10 and the battery 38 from an external power source 39.

[0023] The external power source 39 may, for example and without limitation, be a connection to an electrical grid, to a generating device (e.g., a gas generator), to a storage battery (e.g., those used in solar or wind power systems), or to another power supply that supplies electrical energy to the vehicle 10. Depending on the external power source 39, the time required to charge the battery 38 may vary. For example, rapid chargers may fully charge the battery 38 in less than one hour, while chargers that operate off standard household wiring (110 volts or 240 volts) may take longer.

[0024] In some configurations of the vehicle 10, the battery 38 may be used as a power source, and therefore the OBCM 36 may also supply electrical power to the electrical grid or to devices or accessories within the vehicle 10. Furthermore, the OBCM 36 may also supply electrical power to devices, such as cellular phones and the like, that an operator of the vehicle 10 may power via electrical connections within the IPE 34 of the vehicle 10.

[0025] Therefore, the OBCM 36 may be a bidirectional battery charger and discharger. In many cases, the battery 38 is most efficiently charged when the battery 38 is heated to a predetermined target temperature. In one aspect, the predetermined target temperature is approximately 25° Celsius. However, depending on the assembly and the thermal requirements of the thermal management system 12, the predetermined target temperature of the battery 38 may vary. In one example, to achieve the target temperature range, the battery 38 may be electrically heated via the electrical energy supplied by the OBCM 36. In this example, the controller 16 effectively overrides the OBCM 36 or drives the OBCM 36 in a computationally inefficient manner, e.g., by off-phasing, to convert a predetermined amount of electrical energy from the external power source 39 into thermal energy, e.g., to increase the temperature of the battery 38.

[0026] In another example, the battery 38 itself is charged in a computationally inefficient manner. That is, the battery 38 is charged inefficiently, such that a portion of the electrical energy driven by the OBCM 36 into the battery 38 is converted to heat energy, which is then stored in the mass of the battery 38 while the battery 38 is being charged. In yet another example, heat energy is transferred to the battery 38 via the coolant 28 carried by the coolant circuit 24, from other heat sources inside and outside the coolant circuit 24. The coolant circuit 24 may include a coolant heater 30. The coolant heater 30 is an electrically driven heater, such as a resistive heater, that adds heat energy to the flow of the coolant 28. In some examples, the temperature of the battery 38 is regulated by the OBCM 36 after the battery has been sufficiently electrically charged.

[0027] In configurations, the vehicle 10 includes a braking system 37 with a regeneration function. In vehicles 10 with regenerative braking systems, an electric motor 40 is used as an electric generator. The electricity generated by the electric motor 40 is fed back to the battery 38 by the OBCM 36. In some battery electric vehicles and hybrid vehicles, the energy is also stored in a capacitor bank (not shown) or mechanically in a rotating flywheel (not shown). Under certain circumstances, when the controller 16 and the OBCM 36 determine that the battery 38 is fully charged or additional heating is otherwise desired, the electricity generated by the electric motor 40 may be converted to heat energy and stored in the mass of the battery 38, other components of the thermal management system 12, or vented from the thermal management system 12 to the ambient air.

[0028] Also with reference to the Fig. 3 and Fig. 4 and further with reference to the Fig. 1 and Fig. 2, additional views of components of the thermal management system 12 are shown. To control the temperature of the battery 38, the coolant circuit 24, in some examples, includes a battery bypass 42. Generally, the battery bypass 42 is operable to selectively flow the cooling fluid 28 through the battery 38 or to bypass the battery 38 under certain conditions. For example, the battery bypass 42 is placed in a closed position when the temperature of the battery 38 is below the preferred temperature of the battery 38. In such an example, the cooling fluid 28 flows through the battery 38 and transfers thermal energy to the battery 38 from the OBCM 36, the coolant heater 30, and other components of the thermal management system 12.

[0029] In another example, the battery bypass 42 is placed in an open position when the battery temperature is above the optimal temperature of the battery 38. In the second example, the flow of the cooling fluid 28 is diverted away from the battery 38. The controller 16 manages or directs the flow of the cooling fluid 28 through the battery bypass 42 via at least a first bypass valve 44 and a second bypass valve 46. The first bypass valve 44 serves to selectively direct the flow of the cooling fluid 28 bypassing a second of the various thermal fluid circuits 14, namely around a power unit 48 disposed within a power unit oil circuit 62. The power unit 48 provides torque to move the vehicle 10. The second bypass valve 46 serves to selectively direct the flow of the cooling liquid 28 around a third of the various thermal fluid circuits 14, namely around a cooler 50 of a refrigerant circuit 52.Depending on the requirements of the thermal management system 12, the first bypass valve 44 and the second bypass valve 46 may be, by way of example only, variable force solenoids or valves (VFS), variable bleed solenoids or valves (VBS), or binary or mode-controlled solenoids or valves.

[0030] In the example of Fig. 3, the first bypass valve 44 is of the VFS or VBS type. Accordingly, the first bypass valve 44 is configured to be varied along a continuous spectrum between a fully closed and an open state. In the fully closed state, the first bypass valve 44 prevents the entire flow of cooling liquid 28 that encounters an inlet of the first bypass valve 44 from flowing through the first bypass valve 44 to an outlet of the first bypass valve 44. In the fully open state, however, the first bypass valve 44 will make the entire flow of cooling liquid 28 that encounters the inlet of the first bypass valve 44 available to the outlet of the first bypass valve 44. The first bypass valve 44 should be understood to vary the valve opening in accordance with the flow requirements of the thermal management system 12 for the cooling fluid 28.

[0031] In Fig. 3 and with reference to Fig. 2, the upper half of the valve diagram shows a situation in which the drive unit 48 receives heat energy from the cooling liquid 28 via a heat exchanger device, e.g., a transmission oil cooler (TOC) 60. The upper half of the valve diagram shows that the first bypass valve 44 provides a variable flow rate through a radiator 54 and the cooler 50 and also supplies cooling liquid 28 to the TOC 60. In the lower half of the valve diagram in Fig. 3, the valve diagram shows a situation in which the first bypass valve 44 diverts coolant 28 away from the TOC 60, thereby completely bypassing heat exchange with the drive unit's oil circuit 62. However, the first bypass valve 44 continues to provide a variable flow through the radiator 54 and cooler 50.

[0032] In the example of Fig. 4, and further with reference to the Fig. 1 and Fig. 2, the second bypass valve 46 is of the binary or mode-controlled variety. That is, the second bypass valve 46 is a binary valve that only has a fully open and a fully closed state. In the fully closed state, the second bypass valve 46 prevents all flow of cooling fluid 28 that hits an inlet of the second bypass valve 46 from flowing through an outlet of the second bypass valve 46. In the fully open state, however, the second bypass valve 46 will direct all flow of cooling fluid 28 that hits the inlet of the second bypass valve 46 to the outlet of the second bypass valve 46.

[0033] The second bypass valve 46 should be understood to operate in an open or closed state according to the flow requirements of the thermal management system 12 for the cooling fluid 28, as directed by the controller 16. In the upper half of the valve diagram of Fig. 4 is the second bypass valve 46 of Fig. 4 in the closed state, in which the flow of the cooling liquid 28 to the cooler 50 is provided. In the lower half of the valve diagram of Fig. 4, the second bypass valve 46, when open, directs the coolant 28 to bypass the radiator 50 and the battery 38 and is thus part of the battery bypass 42. Thus, when the second bypass valve 46 is open, the coolant 28 flows from the second bypass valve 46 directly into the coolant lines 32, which lead to the coolant pump 26.

[0034] In some configurations, the first bypass valve 44 and the second bypass valve 46 selectively direct the flow of the cooling fluid 28 through the radiator 54. The radiator 54 exchanges heat energy between the cooling fluid 28 and the atmosphere outside the vehicle 10. Accordingly, when the radiator 54 is in use, heat energy is removed from the vehicle 10. In some configurations, the radiator 54 operates in conjunction with a fan 56 and an airflow control device, such as a shutter mechanism 58, operable to precisely regulate the temperature of the radiator 54 and, thus, the cooling fluid 28 flowing through the radiator 54.

[0035] In some configurations, the closure mechanism 58 consists of a series of vanes or flaps disposed within an opening (not shown) on an exterior surface of the vehicle 10, such as a forward, side, downward, or upward air intake (not shown), an inlet disposed within a fog lamp housing (not shown), or the like. The vanes or flaps of the closure mechanism 58 are moved through a range of motion that allows for at least one open and one closed position. In several aspects, the controller 16 can variably change the position of the closure mechanism 58 electromechanically using magnets, motors, actuators, and the like, hydraulically, through aerodynamic forces, or any combination of the above means.In the open position, the airflow impinging on the closure mechanism 58 is allowed to pass through the closure mechanism 58 toward the radiator 54 and / or the fan 56. In the closed position, the airflow impinging on the closure mechanism 58 is prevented from passing through to the radiator 54 and / or the fan 56.

[0036] Although the shutter mechanism 58 has been described herein as having open and closed positions, it should be understood that the shutter mechanism 58 can be variably actuated to any position between fully open and fully closed. Thus, the controller 16 can actuate the shutter mechanism 58 to provide and modulate airflow to the radiator 54 when such airflow is desirable and to prevent such airflow when airflow is not needed. In some examples, the controller 16 commands the shutter mechanism 58 to remain closed under a wide range of drive cycle conditions, thereby minimizing the loss of heat energy to the atmosphere via the radiator 54.

[0037] In further examples, the first bypass valve 44 and the second bypass valve 46 variably direct the flow of the cooling liquid 28 through both the battery 38 and the radiator 54, as shown in Fig. 3, thus providing the coolant circuit 24 with the ability to precisely thermally regulate the battery 38 and other components within the coolant circuit 24.

[0038] The first bypass valve 44 selectively directs the flow of cooling fluid 28 through the battery 38 and / or through the TOC 60, which is located in the second of the various thermal fluid circuits 14, namely the power unit oil circuit 62. The TOC 60 is a heat exchange device that provides a means for transferring thermal energy between the coolant circuit 24 and the power unit oil circuit 62. The TOC 60 includes at least two physically separate passages. That is, on a first side of the TOC 60, a cooling fluid passage 28 (not shown) carries the cooling fluid 28 as part of the coolant circuit 24 through the TOC 60. On a second side of the TOC 60, an oil passage (not shown) carries oil 64 through the TOC 60 as part of the power unit oil circuit 62.However, it should be understood that despite the fact that the TOC 60 includes a portion of both the coolant circuit 24 and the oil circuit 62, there is no fluid interface between the coolant 28 and the oil 64 within the TOC 60, thus preventing the coolant 28 and the oil 64 from mixing.

[0039] An oil pump 66 pumps the lubricating oil 64 through a plurality of oil lines 68 that are in fluid communication with the drive unit 48. The drive unit 48 is a plurality of mechanical devices that convert chemical or electrical energy into torque to move the vehicle 10.

[0040] In some configurations, the mechanical devices include an engine 70 and a transmission 72. The engine 70 may be an internal combustion engine (ICE), an electric motor 40, and / or any other type of prime mover without departing from the scope or intent of the present disclosure. In some aspects, the engine 70 operates in conjunction with, or may be entirely replaced by, at least one electric motor 40. The engine 70 and / or the electric motor 40 provide torque that moves the vehicle 10 via the transmission 72.

[0041] The transmission 72 may be a manual, automatic, multi-clutch, or continuously variable transmission, or any other type of electronically, pneumatically, and / or hydraulically controlled vehicle transmission 72, without departing from the scope or intent of the present disclosure. The transmission 72 is mechanically and / or fluidly coupled to the engine 70. The drive unit oil circuit 62 circulates oil 64 through the transmission 72, keeping the internal components of the transmission 72 lubricated. In some aspects, the transmission 72 and the engine 70 share an oil supply 64 via the oil circuit 62. Furthermore, in some examples, the circulating oil 64 is used to heat or warm the transmission 72 during startup of the engine 70 or to cool the transmission 72, if necessary, during heavy use.

[0042] The drive unit 48 has a predetermined optimal operating temperature at which the lubricating oil 64 has desirable viscosity and lubricating properties. In various aspects, the predetermined optimal operating temperature is approximately 70° Celsius. However, depending on the application and the components of the drive unit 48 and in the oil circuit 62 of the drive unit, the optimal operating temperature can vary greatly. For example, in drive units 48 with an internal combustion engine 70, the optimal temperature of the oil 64 circulating through the engine 70 is between approximately 85° Celsius and approximately 120° Celsius. In another example, in drive units 48 with an automatic transmission 72, the optimal temperature of the oil 64 circulating through the automatic transmission 72 can be between approximately 20° Celsius and approximately 110° Celsius.In yet another example, in power units 48 having an automatic transmission 72 coupled to a torque converter (not shown), the temperature of the oil 64 circulating through the torque converter may be between about 90° and about 180° Celsius.

[0043] With further reference to Fig. 4 and further with reference to the Fig. 1-3, the second bypass valve 46 selectively directs the flow of the cooling liquid 28 through the battery 38 and / or through the radiator 50 disposed in the third of the various thermal fluid circuits 14, specifically the refrigerant circuit 52. The radiator 50 is a heat exchange device that provides a means for transferring thermal energy between the coolant circuit 24 and the refrigerant circuit 52. However, like the TOC 60, the radiator 50 includes at least two physically separate passages. That is, on a first side of the radiator 50, a passage (not shown) for the cooling liquid 28 carries the cooling liquid 28 through the radiator 50 as part of the coolant circuit 24. On a second side of the radiator 50, a passage (not shown) carries a refrigerant 74 through the radiator 50 as part of the refrigerant circuit 52.However, it should be understood that despite the fact that the radiator 50 comprises part of both the coolant circuit 24 and the refrigerant circuit 52, there is no fluid interface between the cooling liquid 28 and the refrigerant 74 within the radiator 50 and thus the cooling liquid 28 and the refrigerant 74 are prevented from mixing.

[0044] The refrigerant circuit 52 includes a plurality of refrigerant lines 76 that fluidly connect a variety of devices operable to thermally regulate a passenger compartment (not specifically shown) contained within the vehicle 10. The passenger compartment may be thermally insulated from other heat-generating vehicle components and may receive thermal energy via one or more vents or other (not specifically shown) conduits of a heating, ventilation, and air conditioning (HVAC) system 78. The refrigerant circuit 52 also carries thermal energy to and from the coolant circuit 24 via the radiator 50. The refrigerant circuit 52 includes a variety of operator comfort systems such as the HVAC system 78. Generally, the refrigerant circuit 52 has a heating function and a cooling function.Within the refrigerant circuit 52, the HVAC system 78 provides heated and / or cooled air to a passenger compartment of the vehicle 10. In other words, the HVAC system 78 transports heat energy from a cooler location to a warmer location within the refrigerant circuit 52. In several aspects, the HVAC system 78 functions as a heat pump. That is, the HVAC system 78 is an air conditioning unit capable of both heating and cooling functions.

[0045] In one example, the operator of the vehicle 10 determines a desired passenger compartment air temperature and selects a heating cycle for the HVAC system 78. The HVAC system 78 includes a compressor 80. The refrigerant 74 enters the compressor 80 via the refrigerant line 76, which may be referred to as the suction line 82. The compressor 80 compresses gaseous refrigerant 74, thereby increasing the temperature and pressure of the refrigerant 74. The now highly pressurized and high-temperature refrigerant 74 then exits the compressor 80 via a refrigerant line 76 known as the discharge line 84 and flows into a cabin condenser 86. In some aspects, the cabin condenser 86 is a heat exchange device having a plurality of condenser coils through which the refrigerant 74 flows. The coils are in contact with the atmosphere within the passenger compartment.An HVAC blower or fan 88 blows air over the cabin condenser 86, thereby releasing heat energy from the cabin condenser 86 to the atmosphere within the passenger compartment. In some aspects, the refrigerant circuit 52 includes a second or external condenser 90. The external condenser 90 is in contact with the ambient atmosphere outside the vehicle 10 and, when actuated, releases heat energy from the refrigerant 74 within the vehicle 10 to the atmosphere.

[0046] The HVAC system 78 further includes a plurality of expansion valves 92. Depending on the design parameters or characteristics of the HVAC system 78, the expansion valves 92 may be mechanical thermostatic expansion valves (TXVs) (not specifically shown) and / or electronic expansion valves (EXVs) (not specifically shown). Control of the expansion rate of the refrigerant 74 can be more directly and precisely controlled with EXVs than with TXVs; however, in some cases, it is desirable to use TXVs for cost, simplicity, and the like. Condensed, pressurized, and still slightly warm refrigerant 74 received from the cabin condenser 86 and / or exterior condenser 90 is passed through an expansion valve 92. When the refrigerant 74 is reduced in pressure by the expansion valve 92, the refrigerant 74 cools down.The refrigerant 74 then passes through an evaporator 94. The evaporator 94 is a heat exchange device in which a series of cooling coils (not shown) carry a stream of cooled refrigerant 74.

[0047] The cooling coils exchange heat energy with the passenger compartment atmosphere. The HVAC blower or fan 88 blows air over the cabin evaporator 94, thereby cooling the passenger compartment of the vehicle 10. The refrigerant 74, which has passed through the evaporator 94, is then recycled through the compressor 80. The refrigerant 74 is also selectively routed through an expansion valve 92 to the radiator 50, where heat energy is either gained from or lost to the coolant circuit 24, depending on the relative temperatures of the coolant 28 and the refrigerant 74 and the thermal requirements of the battery 38 and other components of the thermal management system 12.

[0048] In some configurations, the HVAC system 78 may be operated from time to time or continuously by the occupants in the passenger compartment or by the controller 16 depending on the optimal heating and / or cooling needs of the passenger compartment or the optimal heating and / or cooling needs of other components of the thermal management system 12. The HVAC system 78 may operate continuously as a heat pump. As previously discussed, while operating as a heat pump, the HVAC system 78 passes the refrigerant 74 through the condenser 86 in the cabin, thereby releasing the thermal energy in the refrigerant 74 into the passenger compartment and cooling the refrigerant 74. However, because the refrigerant circuit 52 exchanges thermal energy with the coolant circuit 24 in the radiator 50, a temperature of the refrigerant 74 in the refrigerant circuit 52 remains substantially above the freezing point of water.This means that the refrigerant 74 continuously exchanges heat energy with the cooling liquid 28 and via the cooling liquid 28 in the coolant circuit 24 with the oil 64 in the oil circuit 62.

[0049] Thus, as the refrigerant 74 flows through the cabin condenser 86 and the exterior condenser 90, heat energy is removed and cooled as the refrigerant 74 flows through the chiller 50. Thus, because the temperature of the refrigerant 74 remains substantially above the freezing point of water, the cabin condenser 86 remains substantially free of ice accumulation. Similarly, in a second example, the controller 16 directs the refrigerant 74 through the exterior condenser 90, where the refrigerant 74 is cooled by releasing heat energy to the atmosphere, but because the refrigerant 74 also flows through the chiller 50, a temperature of the refrigerant 74 remains substantially above the freezing point of water.

[0050] Therefore, in both the first and second examples, ice formation on both the cabin condenser 86 and the external condenser 90 is prevented, even if one, the other, or both the cabin condenser 86 and the external condenser 90 are used continuously. Furthermore, even if ice accumulates on the cabin condenser 86 or external condenser 90, the controller 16 directs thermal energy from one of the thermal energy storage devices in the oil circuit 62 or the coolant circuit 24 via the expansion valves 92 through the cabin condenser 86 and / or the external condenser 90 to the radiator 50, thus melting the ice accumulation as needed.

[0051] Also with reference to the Fig. 5A-D are schematic diagrams or graphics illustrating thermal management strategies for selectively cooling the battery 38. The strategies related to the Fig. 5A-D can extend the range of the vehicle 10 and the service life of the battery 38.

[0052] Fig. 5A shows a graph 100 illustrating the active cooling of the battery 38 during or after driving. The graph 100 illustrates the tracking of the temperature of the battery 38 and the selective cooling of the battery 38 based on the current and historical operating temperatures. The battery temperature 102 is plotted on the vertical axis, and time 104 is plotted on the horizontal axis.

[0053] A target lifetime battery temperature (TLBT) 106 represents a specific preferred average temperature over the lifetime of the battery 38. The TLBT 106 is vehicle-specific and represents an estimate of the average operating temperature that will allow the battery 38 to achieve its designed lifetime. Generally speaking, the lower the operating temperatures of the battery 38, the longer the battery 38 will last.

[0054] The graph 100 also shows an actual average battery temperature (AABT) 108, which represents the historical average operating temperature of the battery 38 in each specific vehicle 10. The AABT 108 may be determined by the controller 16. The controller 16 also tracks a current battery temperature (CBT) 110. The stored data of the CBT 110 may be used to determine or calculate the AABT 108. The controller 16 is configured to compare the calculated actual average battery temperature to the TLBT 106. This comparison indicates whether the vehicle 10 was operating above or below the preferred temperature range of the TLBT 106.

[0055] As in Fig. 5A, a determination period or initiation period 112 occurs after the vehicle 10 begins traveling. The length of the initiation period 112 may be determined based on specific characteristics of the vehicle 10, based on changes to the CBT 110 (e.g., the initiation period 112 lasts for a 5 degree Celsius change in the temperature of the battery 38), or based on the traveling distance or time. The initiation period 112 is followed by an active period 114 during which the controller 16 determines whether active battery cooling is required. Note that the active period 114 may occur after the vehicle 10 has completed the traveling and is connected to the external power source 39.

[0056] In the Fig. 5A, the controller 16 calculates that the AABT 108 is greater than the TLBT 106. Therefore, during the active period 114, the controller 16 cools the battery 38 to a target battery temperature 116. Depending on the configuration of the vehicle 10, the target battery temperature 116 may be below the TLBT 106, but the battery 38 is cooled at least from the peak value of the CBT 110 when active cooling began.

[0057] If the active period 114 occurs while the vehicle 10 is being driven, or while the vehicle 10 is stationary but not connected to the external power source 39, the energy used to cool the battery 38 will come from stored energy and will reduce the range of the vehicle 10. It is generally preferable to maximize the available range of the vehicle 10. If the active period 114 occurs entirely while the vehicle 10 is not being driven and is connected to the external power source 39, then the energy to cool the battery 38 will come from the external power source 39. However, it should be noted that it is generally preferable to minimize the use of energy from the external power source 39 to reduce costs and carbon generation.

[0058] The controller 16 may determine or calculate the target battery temperature 116 using physics-based algorithms specific to the vehicle 10 and may be determined through testing, modeling, or both. The target battery temperature 116 may be, for example, without limitation, a function of one or more of the following: average battery temperature (such as the AABT 108); actual battery temperature (such as the CBT 110); ambient temperature; mass of the battery 38; learned or predicted drive cycle; and charging power of the external power source 39 or other charging sources in addition to the thermal capacity of the battery 38.

[0059] The temperature of the battery 38 may be affected by the needs and operating conditions of the vehicle 10. For example, and without limitation: the propulsion demand of the vehicle 10 generates heat energy (propulsion heat); heating and cooling the cabin generates heat energy (cabin heat); and charging or discharging the battery 38 generates heat energy (battery heat).

[0060] In one configuration, the following applies: Target battery temperature = Minimum battery temperature during normal propulsion + (cabin energy consumption rate * predicted propulsion time / (battery thermal capacity * mass) / loss function). The loss function is determined by the difference between the battery minimum during normal propulsion and the ambient temperatures, as heat will be dissipated to the environment. With a cabin temperature of 72 degrees Celsius, an expected drive time of 30 minutes, and an ambient temperature of -10 degrees Celsius, the target temperature for battery 38 (with a mass of approximately 500 kg) might be approximately 25 degrees Celsius.

[0061] Fig. 5B shows a graph 120 illustrating the delayed cooling of the battery 38 during or after driving. The battery temperature 122 is shown on the vertical axis and time 124 is shown on the horizontal axis. Similar to the graph 100 in Fig. A target lifetime battery temperature (TLBT) 126 indicates the preferred average temperature over the lifetime of the battery 38, and an actual average battery temperature (AABT) 128 indicates the historical average operating temperature of the battery 38 in this vehicle 10. The controller 16 also tracks a current battery temperature (CBT) 130.

[0062] A determination period or initiation period 132 occurs after the vehicle 10 begins traveling, and an active period 134 follows the initiation period 132. It should be noted that the active period 134 may occur while the vehicle 10 is traveling or after the vehicle 10 has stopped traveling and is connected to the external power source 39.

[0063] The controller 16 is configured to compare the calculated AABT 128 with the TLBT 126. This comparison indicates whether the vehicle 10 was operating above or below the preferred temperature range of the TLBT 126.

[0064] In the Fig. 5B, the controller 16 calculates that the AABT 128 is less than the TLBT 126. Therefore, during the active period 134, the controller 16 determines that it does not yet need to actively lower the temperature of the battery 38 below the TLBT 126. The controller 16 delays cooling the battery 38 based on algorithms that incorporate the AABT 128. Note that in other configurations of the vehicle 10, the controller 16 would often cool the battery 38 toward the TLBT 126 whenever the CBT 130 is greater than the TLBT 126.

[0065] In the example of Fig. 5B, approximately half of the active period 134 occurs while the vehicle 10 is being driven, and the remainder occurs after the vehicle 10 is stopped. The CBT 130 begins to naturally decrease after the vehicle 10 is no longer being driven. Therefore, the CBT 130 does not remain above the TLBT 126 indefinitely, reducing the consumption of energy, whether stored in the battery 38 or from the external power source 39, to cool the battery 38.

[0066] Fig. 5B also shows a maximum threshold temperature 136, which may be determined based on individual characteristics of the battery 38 and the vehicle 10. Regardless of the AABT 128, when the CBT 130 increases to the maximum threshold temperature 136, the controller 16 may use energy to actively cool the battery 38. The maximum threshold temperature 136 represents a value above which the battery 38 may degrade or be affected by its service life, independent of the AABT 128.

[0067] In some configurations, the controller 16 may set or calculate this maximum limit temperature 136 based at least in part on the AABT 128, so that if the vehicle 10 has a very low AABT 128, the maximum limit temperature 136 may be set higher. In such configurations, there may also be an absolute limit above which the controller 16 will never allow the temperature of the battery 38 to rise.

[0068] Furthermore, the controller 16 may adjust the maximum limit temperature 136 based at least in part on the state of charge (SOC) of the battery 38. For example, at lower states of charge, the controller 16 may increase the maximum limit temperature 136, and at higher states of charge, the controller 16 may decrease the maximum limit temperature 136. Further discussion of how the state of charge may affect the operating temperatures selected by the controller 16 can be found in U.S. Patent US 9,376,031 B2, which is hereby incorporated by reference in its entirety. The precise determination of the maximum limit temperature 136 with respect to various states of charge may be a physics-based calculation specific to the vehicle 10 and its components.

[0069] Fig. 5C shows a graph 140 illustrating two examples of active battery cooling during driving based on differences between target and actual average battery temperatures over the lifetime of the driving cycle. Battery temperature 142 is plotted on the vertical axis, and time 144 is plotted on the horizontal axis. A target lifetime battery temperature (TLBT) 146 indicates the preferred average temperature over the lifetime of the battery 38.

[0070] Fig. 5C illustrates two different vehicle driving histories to illustrate two different levels of active cooling. The figure may illustrate two different vehicles 10 or the same vehicle 10 at different times during its driving lifetime. Therefore, the graph 140 includes a first actual average battery temperature (first AABT) 148 and a second actual average battery temperature (second AABT) 149. Note that the first AABT 148 is significantly lower than the TLBT 146, while the second AABT 149 is lower than, but closer to, the TLBT 146.

[0071] The controller 16 also tracks a first current battery temperature (first CBT) 150 and a second current battery temperature (second CBT) 151. A determination period or initiation period 152 occurs after the vehicle 10 begins traveling, and an active period 154 follows the initiation period 152. During the initiation period 152, the first CBT 150 and the second CBT 151 are substantially the same, so both situations begin in a similar manner.

[0072] In the active period 154, the controller 16 compares the calculated first AABT 148 and the first CBT 150 with the TLBT 146. As shown in diagram 140, the first CBT 150 is well above the TLBT 146 and the first AABT is well below the TLBT 146. In this configuration, the controller 16 decides to actively cool the battery 38, but not all the way to the TLBT 146.

[0073] The controller 16 calculates a first difference 156 between the first AABT 148 and the TLBT 146. The controller 16 then actively cools the battery 38 until the first CBT 150 reaches a first target temperature 157 approximately equal to the TLBT 146 plus the first difference 156. As such, the controller 16 cools the battery 38 toward the TLBT 146, but not all the way, which is offset by the specific first difference 156. This effectively causes the resulting operating temperature of the first CBT 150 to equalize around the TLBT 146, so that the first AABT 148 will tend to move toward the TLBT 146 during steady-state operation.

[0074] The controller 16 also calculates a second difference 158 between the second AABT 149 and the TLBT 146. The controller 16 then actively cools the battery 38 until the second CBT 151 reaches a second target temperature 159 approximately equal to the TLBT 146 plus the second difference 158. Thus, the controller 16 cools the battery 38 toward the TLBT 146, but not completely, which is offset by the situation-specific second difference 158. This effectively causes the resulting operating temperature of the second CBT 151 to equilibrate around the TLBT 146, so that during subsequent steady-state operation, the second AABT 149 will tend to move toward the TLBT 146.

[0075] By using a target temperature offset from the TLBT 146 by the first difference 156 or the second difference 158, the vehicle 10 saves energy compared to cooling to the TLBT 146. However, the target operating temperatures contribute to an average temperature that corresponds to the TLBT 146.

[0076] Fig. 5D shows a graph 160 illustrating the early cooling of the battery 38 based on a predicted drive cycle in which the temperature of the battery 38 is likely to increase in the future. Temperatures 162 are plotted on the vertical axis, and time 164 is plotted on the horizontal axis. A target lifetime battery temperature (TLBT) 166 illustrates the preferred average temperature during the lifetime of the battery 38. The graph 160 illustrates an actual average battery temperature (AABT) 168 that is lower than the TLBT 166.

[0077] In the Fig. In the examples illustrated in Figures 5A-5C, the controller 16 largely monitored the current and past operating conditions of the vehicle 10 and made its decisions based on those conditions. Fig. 5D shows an example of the controller 16 also using predictive algorithms to estimate upcoming driving conditions and a future battery temperature of the vehicle 10. For example, the driver of the vehicle 10 may input information about a driving route into a navigation system so that the controller 16 knows where the vehicle 10 will go in the future and can also estimate the times at which the vehicle 10 will enter certain areas or encounter certain driving conditions. Note that the driving route may include both geographic and topographical information, so that in addition to the roads and areas through which the vehicle 10 will travel, the controller also detects elevation changes along the route.

[0078] Alternatively, the controller 16 may predict the travel route based on the vehicle's 10 history, such as regular commutes or patterned drive cycles. For example, the vehicle 10 may regularly be driven on generally level terrain for an initial portion of the drive cycle and then generally uphill for the remainder of the drive cycle. Uphill driving increases the thermal propulsion energy generated in the battery 38, so the later portions of the drive cycle may increase the temperature of the battery 38 due to propulsion loads.

[0079] The controller tracks a current battery temperature (CBT) 170 for the battery 38 during and after the drive cycle of the vehicle 10. An outside air temperature 172 represents the conditions surrounding the vehicle while driving. It should be noted that the outside air temperature 172 may differ from the ambient temperature at the beginning of the trip, particularly if the vehicle 10 is parked in a climate-controlled garage. Therefore, the outside air temperature 172 may be determined based on communication networks and weather data.

[0080] In addition, the outside air temperature 172 may be estimated based on the predicted drive cycle or the driving distance. As in Fig. As shown in Figure 5D, the outside air temperature 172 is predicted to rise in the later portion of the trip. This may occur, for example, and without limitation, when the vehicle 10 begins its drive cycle in the morning and ends it in the afternoon, or when the vehicle travels from an area of ​​low temperatures to an area of ​​relatively higher temperatures. A maximum threshold temperature 174 indicates a level above which the CBT 170 should not exceed.

[0081] The outside air temperature 172 affects the CBT 170 by changing the ability of the battery 38 to dissipate heat to the air around the vehicle 10. Furthermore, as the outside air temperature 172 increases, additional energy may be required for the HVAC system 78 to cool the cabin. As the battery 38 discharges energy to the HVAC system 78 to cool the cabin, heat energy is released within the battery 38, so the temperature of the battery 38 tends to increase. Therefore, as the drive cycle predicted for the vehicle 10 progresses, the controller 16 predicts that it will be more difficult to maintain the CBT 170.

[0082] As in Fig. 5D, the controller 16 performs the active cooling of the battery 38 during a usage period 176. It should be noted that during the usage period 176, no other cooling of the battery 38 is required. The AABT 168 for the vehicle 10 is significantly below the TLBT 166, so the controller 16 could have determined that no cooling (as in the example Fig. 5D) or only minimal cooling (as in the example Fig. 5C) is required. Furthermore, the CBT 170 did not rise to the maximum limit temperature 174 at the beginning of the operating period 176.

[0083] However, without active cooling during the operating period 176, the temperature of the battery 38 would probably have risen above the maximum limit temperature 174, as shown by an unshifted CBT 180. As shown in Fig. 5D, the future battery temperature would have moved beyond the maximum limit temperature 174. The deployment period 176 performs active cooling during a time when the battery 38 is not yet at problematic temperature levels, but in response to a prediction that such levels could be reached later in the drive cycle.

[0084] Additionally, the controller 16 may analyze the operating conditions of the vehicle 10 to determine whether it is more energy efficient to implement active cooling during the usage period 176 rather than in a subsequent time period. This may be referred to as opportunity cooling because it involves determining whether there is an opportunity to cool more efficiently now than in the future (when cooling is likely to be needed). For example, as the outside air temperature 172 increases, the heat pump function of the HVAC system 78 may be less efficient at transferring heat energy from the battery 38 to the environment via the cooling circuit 24 and the radiator 50. Additionally, as the outside air temperature 172 increases, the HVAC system 78 is needed to cool the interior of the vehicle 10.Therefore, the range of the vehicle 10 may be extended by cooling the battery 38 during the usage period 176, as opposed to a later cooling period when the HVAC system 78 would be less efficient.

[0085] If the controller 16 determines the efficiency or ability to cool the battery 38, this may be referred to as cooling costs. The controller 16 may also use predicted route information to predict future cooling costs for the remainder of the trip. Therefore, the controller 16 may decide that it is more efficient to cool the battery 38 during an early portion of the trip if cooling costs are low during the early portion and are expected to increase later in the drive cycle, even if it would not otherwise do so.

[0086] Cooling costs can be quantified by the Coefficient of Performance (COP), which varies based on the specific cooling systems used. For example, during the operating period 176, relatively low cooling costs may be incurred—i.e., the COP is between 10 and 25. However, later in the drive cycle, after the outside air temperature 172 rises and the unshifted CBT 180 would have moved close to the maximum limit temperature 174, relatively higher cooling costs may occur—i.e., the COP is between 2.5 and 5. The controller compared the current COP to the predicted COP and allowed opportunity cooling during the lower COP. This reduces the amount of energy used to cool the battery 38 and extends the driving range.

[0087] Additionally, it should be noted that the controller 16 may use the predicted state of charge to change the maximum limit temperature 174 so that the decision whether to initiate cooling early—ie, to implement this deployment period 176—incorporates the predicted state of charge.

[0088] For example, if the predicted temperature rise for the battery 38 in the next 30 minutes will be higher than the maximum threshold temperature 174 at the predicted SOC, then the controller 16 will enable opportunity cooling during the use period 176. However, if the predicted temperature rise for the battery 38 in the next 30 minutes is lower than the maximum threshold temperature 174 at the predicted SOC, the controller 16 may disable opportunity cooling.

[0089] As in Fig. 5D, the unshifted CBT 180 would have risen well above the maximum limit temperature 174, requiring very aggressive and / or inefficient cooling of the battery 38. However, with active cooling during the shift time 176, it is not necessary for the HVAC system 78 to cool the battery 38 if the elevated outside air temperature 172 makes cooling the battery 38 relatively difficult. Later in the drive cycle, as the CBT 170 approaches the maximum limit temperature 174, the controller 16 commands additional active cooling to lower the temperature of the battery 38.

[0090] It should be noted that the specific mechanisms or techniques for cooling the battery 38 shown and discussed herein are not limiting, and other structures and mechanisms may be used. For example, and without limitation, thermoelectric devices, dedicated coolant circuits, air cooling, or combinations thereof may be used for the methods for selectively cooling the battery 38 discussed herein.

[0091] If the controller 16 determines that the battery 38 should be actively cooled, as described in the Fig. 5A, Fig. 5C and Fig. 5D, the controller 16 may vary the cooling aggressiveness depending on the condition of the vehicle 10 and the environment. The controller 16 may determine or calculate the cooling aggressiveness using physics-based algorithms specific to the vehicle 10, which may be determined through testing, modeling, or both. The cooling aggressiveness captures both the cooling time and the amount of energy used to cool the battery 38.

[0092] Cooling aggressiveness may, for example and without limitation, be a function of one or more of the following inputs: predicted battery temperature, predicted battery thermal energy production, ambient temperature and humidity, predicted cabin thermal utilization, and current and predicted cooling effectiveness (as quantified by COP). Controller 16 determines cooling aggressiveness by calculating predicted energy savings from aggressive cooling now, as opposed to waiting and reactive cooling later. If the predicted reactive cooling efficiency is significantly greater than the predicted aggressive cooling efficiency, the system recognizes that it will cost less energy to cool aggressively now.

[0093] With reference to Fig. 6 and further with reference to the Fig. 1-5D, a flowchart of a method 200 for executing thermal management strategies to selectively cool the battery of a vehicle with an electric propulsion system, such as vehicle 10, is shown. The method 200 illustrates some of the inputs and decisions that the controller 16 uses to determine when and how much to actively cool the battery 38.

[0094] The Fig. The steps illustrated in Figure 6 are exemplary of a particular algorithm or process and are not limiting. None of the steps are required, and all steps may be optional, whether or not marked as such. The order of the steps or processes illustrated is also not limiting. As will be appreciated by those skilled in the art, the steps may be rearranged or reordered.

[0095] The Fig. The method 200 shown in Figure 6 may be used to control some of the Fig. 5A-D and others. However, it should be noted that neither the examples nor the Fig. 5A-D nor the steps and sequence of the method 200 are limiting. Step 210: Start / Initialize.

[0096] The method 200 may not be initiated until invoked by the controller 16. For example, the method 200 may be initiated whenever the vehicle 10 is being driven, has recently been driven, or is connected to the external power source 39.

[0097] The method 200 may be executed by the controller 16 and may run constantly or iteratively in a loop. It should be noted that the method shown in the flowchart of Fig. 6 may not depict all possible processes or algorithms described herein, so the method 200 is not exclusive of any processes not depicted in the flowchart. Furthermore, value comparisons are approximate, so either greater-than or less-than designations may imply equality and slight variations of up to 5%. Step 212: Determine the current battery temperature (CBT).

[0098] The method 200 determines the CBT of the battery 38. This may include reading one or more sensors associated with the battery 38, the coolant circuit 24, or other locations of the vehicle 10. In addition, interpretation of sensor data or modeling of sensor data or other inputs may be used to calculate or determine the CBT. Step 214: Calculate the actual average battery temperature (AABT).

[0099] The CBT calculated in step 212 is generally stored by the controller 16. Previous values ​​of the CBT can then be used to calculate the AABT. Note that the AABT can be calculated as a true average or have a weighting applied to it. Step 216: Is the CBT greater than the target lifetime battery temperature (TLBT)?

[0100] The CBT is compared to the TLBT. If the CBT is greater than the TLBT, the method 200 may include some remedy.

[0101] In some configurations of method 200, the TLBT may also be compared to a predicted CBT of the current drive cycle. For example, even if the current CBT is less than the TLBT, the controller 16 may predict an increase in CBT later in the drive cycle and return a positive value—i.e., the CBT is greater than the TLBT—at decision step 216. Step 220: End / Loop.

[0102] If the determination in decision step 216 is negative—i.e., the CBT is less than the TLBT—the method 200 may abort or terminate. The method 200 may run continuously, so that all steps can occur at any time. Alternatively, the method 200 may run iteratively, e.g., according to a schedule, in a loop. Regardless, the process is likely to repeat at the end of the method 200 as long as any initialization conditions exist. Therefore, after reaching the end / loop step 220, the method may return to the start step 210. Step 222: Is the AABT greater than the TLBT?

[0103] If the determination in decision step 216 is positive—that is, the CBT is greater than the TLBT—the method 200 continues to determine whether the AABT is greater than the TLBT. As in Fig. As shown in Figure 5A, if the AABT is larger than the TLBT, the fact that the CBT is larger than the TLBT may not be ignored. Step 224: Cool the battery to TLBT or lower.

[0104] If the determination in decision step 222 is positive—i.e., the AABT is greater than the TLBT—the method 200 has determined that there is a need to reduce the temperature of the battery 38 (i.e., the CBT), which may extend the life of the battery 38. Therefore, the controller 16 performs active cooling of the battery 38, e.g., via the coolant circuit 24 and the HVAC system 78 or other means.

[0105] In some configurations, the controller 16 may cool the battery 38 to a target temperature substantially equal to the TLBT. However, in other configurations, the method 200 may include calculating a target temperature below the TLBT based on past, current, and predicted operating conditions of the vehicle 10. After cooling the battery 38 to the target temperature, the method 200 may continue to the end / loop step 220. Step 226: Is the CBT greater than the trigger temperature?

[0106] If the determination in decision step 222 is negative—i.e., the AABT is less than the TLBT—the method 200 proceeds to determine whether the CBT is greater than a trigger temperature. As discussed above, the trigger temperature may represent a level above which the controller 16 does not allow the battery 38 to operate, regardless of historical operation, including a low AABT. Step 228: Delay cooling.

[0107] If the determination in decision step 222 is negative—i.e., the CBT is less than the trigger temperature—the method 200 delays cooling of the battery 38. The amount of time active cooling is delayed may be configured based on the requirements of the particular vehicle, or the controller 16 may continue the delay as long as each iteration or loop of the method 200 results in cooling being delayed. The method 200 may then proceed to the end-loop step 220. Step 230: Calculate the target temperature.

[0108] If the determination in decision step 226 is positive—that is, the CBT is greater than the trigger temperature—the method 200 has determined that active cooling of the battery 38 is warranted. Therefore, the controller 16 calculates or determines a target temperature to which the battery 38 will be cooled.

[0109] The target temperature can be determined using a function as described above. Alternatively, and without limitation, other target temperatures can include: the TLBT; the TLBT plus the difference between the TLBT and the AABT; or a preset value above or below the TLBT. Step 232: Cool battery to target temperature.

[0110] Method 200 then proceeds to actively cool battery 38 to the target temperature. Note that this step may involve determining cooling aggressiveness, which may alter the rate / time to the target temperature.

[0111] As described above, in some situations, method 200 may determine that battery 38 should be cooled very aggressively so that battery 38 quickly reaches the target temperature. This may occur when ambient or driving conditions are favorable for efficient transfer of thermal energy from battery 38 to the atmosphere or cabin. In other situations, overall energy consumption may benefit from slower cooling, so a less aggressive cooling strategy is used to ultimately bring battery 38 to the target temperature.

[0112] Also with reference to the Fig. 7A-C, in addition to the Fig. 1-6, schematic diagrams are shown illustrating example thermal management strategies for selectively heating a battery, such as the battery 38 of the vehicle 10. Each of these diagrams illustrates heating while the vehicle 10 is off and connected to the external power source 39 so that preconditioning can be used to extend the eventual range of the vehicle 10. Each of the Fig. 7A-C, the charging process begins when the vehicle 10 is not running and has been connected to the external power source 39 for charging. The controller 16 can perform any calculations or determinations, as well as any instructions or commands. The external power source 39 generally refers to power drawn from the grid, such as that drawn when connected to the driver's home or garage, but can also refer to connection to home or industrial batteries. The connection to the external power source 39 may also be referred to as wall power because the vehicle 10 is often connected to an electrical outlet or wall-mounted power supply.

[0113] Fig. 7A shows a graph 300 illustrating the selective heating of battery 38 for use as a thermal storage device based on a predicted drive cycle following the off period of vehicle 10. Battery temperature 302 is plotted on the vertical axis, and time 304 is plotted on the horizontal axis.

[0114] The controller tracks or determines a current battery temperature (CBT) 308. An unconditioned temperature 310 is also shown in the graph 300, as will be explained later. A connection time 312 occurs after the vehicle 10 is connected to the external power source 39—i.e., the vehicle 10 is plugged into the wall outlet—which is near the beginning of the Fig. 7A shown period.

[0115] In the Fig. 7A, the controller 16 instructs the OBCM 36 to begin charging the battery 38 substantially at connection time 312. The OBCM 36 charges the battery 38 until a charging stop 314, which may coincide with the battery 38 reaching a predetermined state of charge (SOC) or with another event, such as an increase in the cost of electricity from the external power source 39 (as may occur with smart metering of municipal power utilities). A charging period occurs between the connection time 312 and the charging stop 314, where the elapsed time may be referred to as the charging period.

[0116] As in Fig. 7A, the CBT 308 increases during the charging period because the charging process generates heat energy in the battery 38. However, after the charging stop 314, the CBT 308 decreases. In low-temperature environments where the cabin of the vehicle 10 will need to be heated, the decrease in CBT 308 represents lost heat energy that could have been used to heat the cabin (possibly in conjunction with the normal operation of the heat pump of the HVAC system 78). If stored, the heat energy of the battery 38 could be transferred to the interior of the vehicle 10, reducing the amount of energy required to heat the cabin during the subsequent drive cycle.

[0117] Therefore, the controller 16 can predict a cabin heating temperature (CHT) of the vehicle 10 during its next drive cycle. This can be done, for example and without limitation, by comparing and analyzing previous drive cycles so that the controller 16 determines regular driving patterns for the vehicle 10. For example, the controller 16 can determine that the vehicle 10 is started at approximately 7:15 a.m. each weekday and driven for approximately 35-40 minutes, and that the driver sets the cabin temperature to approximately 71 degrees Fahrenheit (22 degrees Celsius).

[0118] It should be noted that, by way of example and without limitation, controller 16 may be in communication with cloud-based computing or data storage systems to assist in determining and predicting drive cycles and likely weather conditions. The predicted cabin heating temperature helps controller 16 determine the amount of thermal energy needed to heat the vehicle cabin, so that controller 16 can determine the amount of thermal energy stored in battery 38 that would contribute to achieving the cabin heating temperature without removing chemical energy from battery 38.

[0119] As in Fig. As shown in Figure 7A, during a heater start 316, the controller 16 activates the coolant heater 30, which may be an electrically driven resistance heater, to add thermal energy to the flow of the coolant 28 through the coolant circuit 24. This thermal energy is absorbed in the battery 38, causing the CBT 308 to rise relative to its unconditioned path. The thermal energy obtained from the resistance heater may be referred to as auxiliary heating.

[0120] Therefore, after some time of preconditioning the battery 38, the CBT 308 rises to a preconditioned target temperature 318. In comparison, an unconditioned temperature 320 demonstrates the temperature of the battery 38 that would have occurred after the same period of time without active heating of the battery 38 by the coolant heater 30.

[0121] The preconditioned target temperature 318 may also be referred to as a thermal storage temperature, as it represents the amount of thermal energy stored in the battery 38. The thermal storage temperature is higher than a target operating temperature for the battery 38, which is the temperature that the controller 16 would normally aim for if it were not using the battery 38 as a thermal storage medium. Several example target operating temperatures are provided, which relate to the discussion in the Fig. 5A-D, although many configurations may use the TLBT as the target operating temperature.

[0122] As in Fig. 7A, the preconditioned target temperature 318 occurs substantially simultaneously with a trip start time 325, so that the additional thermal energy stored in the battery 38 can be used immediately at the beginning of the drive cycle to heat the cabin of the vehicle 10. It should be noted that the energy for the coolant heater 30 is drawn from the external power source 39, as opposed to being drawn from the battery 38, so that the electric driving range of the vehicle 10 is not reduced by storing thermal energy in the battery 38 as thermal mass.

[0123] In contrast, if the HVAC system 78 and a resistive heater or heat pump incorporated therein were used to heat the cabin of the vehicle 10 from the chemical energy stored in the battery 38 (which is converted to electrical energy), the electric range would be reduced. After the trip start time 325, the CBT 308 decreases because thermal energy is extracted from the battery 38 to heat the cabin, so there is essentially no long-term temperature increase in the battery 38.

[0124] The vehicle 10 may use other heat generation techniques to heat the battery 38 as a storage mass for thermal energy. For example, and without limitation, the controller 16 may effectively override the OBCM 36 or drive the OBCM 36 in a computationally inefficient manner, e.g., by off-phasing, to convert some electrical energy from the external power source 39 into thermal energy, or the OBCM 36 may rapidly cycle power into and out of the battery 38 (charge / discharge cycling) to generate thermal energy within the battery 38. The other, non-charging techniques used to transfer thermal energy to the battery 38 may be referred to as auxiliary heating.

[0125] Fig. 7B shows a graph 330 illustrating the modified start time of the charging cycle so that thermal energy is selectively stored in the battery 38 as a result of charging. The graph 330 shows the selective heating of the battery 38 for use as thermal storage based on a predicted drive cycle.

[0126] Battery temperature 332 is plotted on the vertical axis, and time 334 is plotted on the horizontal axis. The controller tracks or determines a current battery temperature (CBT) 338. An unconditioned or instantaneous charge temperature 340 is also plotted on graph 330, as explained later. A connection time 342 occurs after the vehicle 10 is connected to the external power source 39—i.e., the vehicle 10 is connected to wall power.

[0127] In the Fig. 7B, the controller 16 has determined that a trip start time 345 is well after the plug-in time 342, so that the charging time does not need to begin immediately after the plug-in time 342 in order to sufficiently charge the battery 38 before the next drive cycle begins.

[0128] The factors used to predict the trip start time may include, for example, and without limitation, the month of the year, day of the week, trip history, and inputs from the driver of the vehicle 10. The driver inputs may be provided via an app or a web-based interface that allows the driver to communicate information directly to the vehicle. For example, and without limitation, the driver may tell the controller 16 exactly when the next trip start time is scheduled, alert the controller 16 that a particular route will be traveled in the next drive cycle, or that the next trip start time will be significantly earlier than usual.

[0129] The immediate charging temperature 340 illustrates the temperature of the battery 38 if the controller 16 had ordered immediate charging substantially at the connection time 342, which is the likely pattern for many electric vehicles. Fig. However, in the example shown in Figure 7B, the controller 16 instructs the OBCM 36 to begin charging the battery 38 at a delayed charging time 343 calculated to fully charge the battery 38 before the trip start time 345, but delayed from the connect time 342. The OBCM 36 charges the battery 38 until a charging stop 344, such that a charging time (where the lapse of time is a charging duration) occurs between the delayed charging time 343 and the charging stop 344.

[0130] As in Fig. 7B, the CBT 338 increases during the charging time because the charging process generates heat energy in the battery 38. Due to the delayed charging time 343, the charging stop 344 is closer to the trip start time 345. As shown by the CBT 338 and the immediate charging temperature 340, at the trip start time 345, a preconditioned target temperature 348 is higher than an unconditioned temperature 350. Therefore, more heat energy is stored in the battery 38 due to the calculated delay in the charging time. The preconditioned target temperature 348 may also be referred to as the heat storage temperature because it represents the amount of heat energy stored in the battery 38.

[0131] In the example of Fig. 7B, the charging time is still completed before the trip start time 345. For example, if the controller estimates that the charging time will take approximately two hours, it may begin charging the battery 38 approximately three hours before the predicted trip start time. If the vehicle 10 is driven early, there will likely be sufficient heat energy from the natural charging energy and a sufficient state of charge of the battery 38. Alternatively, for example and without limitation, the controller 16 may begin the charging time when approximately 125% of the time required for the charging time remains until the trip start time, so that a buffer of approximately 25% exists.

[0132] The controller 16 strives to ensure both a sufficient state of charge in the battery 38 and sufficient stored thermal energy in the battery 38. Therefore, it may begin the charging time when, by way of example and without limitation, it predicts that the charging time will last at least 80% of the time remaining before the trip start time, so that only a small amount of the stored thermal energy is dissipated from the battery.

[0133] At the start of travel time 345, the additional thermal energy stored in the battery 38 can be used to heat the cabin of the vehicle 10 immediately at the beginning of the drive cycle. In contrast to the Fig. 7A, which uses additional wall current to heat the battery 38, the strategy of Fig. 7B with the increased heat energy stored in the battery 38, completely heat that is naturally generated as a result of the charging time.

[0134] However, the controller 16 has delayed the start of the charging period to allow the battery 38 to carry thermal energy for use at the start of the drive cycle at the trip start time 345. This is essentially free energy that can be used to heat the vehicle cabin, rather than using the chemical energy stored in the battery 38 to power resistive heaters. The saved energy results in an extended electric driving range of the vehicle 10 and costs the operator of the vehicle 10 nothing for energy purchased from the external power source 39.

[0135] Fig. 7C shows a graph 360 illustrating the additional heat energy added to the battery during recharging, such that the heat energy is selectively stored in the battery 38 for later use. The graph 360 illustrates the selective heating of the battery 38 to be used as a heat storage device based on a predicted drive cycle.

[0136] Battery temperature 362 is shown on the vertical axis and time 364 is shown on the horizontal axis. The controller tracks or determines a current battery temperature (CBT) 368. An unconditioned temperature 370 is also shown on graph 360, as will be explained herein.

[0137] A connection time 372 occurs substantially simultaneously while the vehicle 10 is connected to the external power source 39 - ie, the vehicle 10 is connected to the wall power. In the Fig. 7C, the controller 16 instructs the OBCM 36 to begin charging the battery 38 substantially at connection time 372. The OBCM 36 charges the battery 38 until a charging stop 374. A charging time occurs between the connection time 372 and the charging stop 374.

[0138] In this case, however, the charging stop 374 essentially coincides with a trip start time 375. This situation may occur, by way of example and without limitation, if the vehicle 10 is returned to its charging station later in the day than usual.

[0139] The controller 16 still correctly predicts the trip start time 375, so the controller 16 takes the shortened charging and preconditioning time into account. Therefore, early in the charging period, the controller 16 commands additional heating of the battery 38 with current from the external power source 39. This additional heating ensures both that the battery 38 is sufficiently charged for the upcoming drive cycle and that sufficient thermal energy is stored in the battery 38 for heating the cabin.

[0140] A preconditioned target temperature 378 indicates the temperature of the battery 38 at the trip start time 375 with the aid of the auxiliary heater, and an unconditioned temperature 380 indicates the temperature the battery 38 would have reached without the auxiliary heater. The preconditioned target temperature 378 may also be referred to as the thermal storage temperature because it represents the amount of thermal energy stored in the battery 38.

[0141] As in Fig. As shown in Figure 7C, the CBT 368 increases during the charging time as heat energy is generated in the battery 38 by the charging process. Because the controller 16 commands additional heating, the CBT 368 increases further compared to the unconditioned temperature 370, which represents the temperature of the battery 38 caused solely by charging. Therefore, heat energy is stored in the battery 38 due to the natural charging heat energy and the additional heat energy generated by intentionally heating the battery 38.

[0142] At the start of the trip time 375, the additional thermal energy stored in the battery 38 can be used to heat the cabin of the vehicle 10 immediately at the beginning of the drive cycle. In contrast to the Fig. 7A, which used only additional wall current to heat the battery 38, and in contrast to the strategy used in Fig. 7B, which used only the natural charging power to heat the battery 38, combines the strategy of Fig. 7C both the charging power and the wall current to store additional heat energy in the battery 38.

[0143] The increased heat energy generated in battery 38 as a result of the strategy of Fig. 7C allows the cabin to be heated without tapping the stored chemical energy of battery 38. The saved energy results in an extended electric driving range for vehicle 10.

[0144] It should be noted that all Fig. 7A-C are subject to limit requirements for the temperature of the battery 38. For example, even if it would be efficient to further heat the battery 38 for heating the cabin, the controller 16 will not do so if the temperature of the battery 38 is or would be above a heating limit. The heating limit may be, by way of example and without limitation: the same as the maximum limit temperature 136, which is set with respect to Fig. 5B; a general battery protection limit; or another value specific to the techniques discussed herein for using the battery 38 as a thermal storage mass.

[0145] With reference to Fig. 8 and further with reference to the Fig. 1-7C is a flowchart of a method 400 for executing thermal management strategies for selectively heating a battery of a vehicle with an electric propulsion system, such as vehicle 10. Method 400 illustrates some of the inputs and decisions controller 16 uses to determine when and to what extent to heat battery 38.

[0146] The Fig. The steps illustrated in Figure 8 are exemplary of a particular algorithm or process and are not limiting. None of the steps are required, and all steps may be optional, whether or not marked as such. The order of the steps or processes illustrated is also not limiting. As will be appreciated by those skilled in the art, the steps may be rearranged or reordered.

[0147] The Fig. The method 400 illustrated in Figure 8 may be used to perform some of the Fig. 7A-C, and others. However, it should be noted that neither the examples in Fig. 7A-C nor the steps and flow of method 400 are limiting. Step 410: Start / Initialize.

[0148] The method 400 may not be initiated until invoked by the controller 16. For example, the method 400 may be initiated whenever the vehicle 10 has recently completed a drive cycle and has been connected to the external power source 39.

[0149] The method 400 may be executed by the controller 16 and may run continuously or iteratively in a loop. It should be noted that the method illustrated in the flowchart of Fig. 8 may not depict all possible processes or algorithms described herein, so the method 400 is not exclusive of any processes not depicted in the flowchart. Furthermore, value comparisons are approximate, so either greater-than or less-than designations may imply equality and also slight variations of up to 5%. Step 412: Determine the current battery temperature (CBT).

[0150] Method 400 determines the CBT of battery 38. This may include reading one or more sensors associated with battery 38, cooling circuit 24, or other locations of vehicle 10. Additionally, interpretation of sensor data or modeling of sensor data or other inputs may be used to calculate or determine the CBT. Step 414: Predict trip start time.

[0151] Method 400 predicts or estimates when the next drive cycle of vehicle 10 will occur. The start of the drive cycle determines the amount of time available to controller 16 to precondition the trip. Historical drive cycle data for the specific vehicle 10 may be used to predict the trip start time. As discussed above, factors used to predict the trip start time may include, for example, and without limitation, the month of the year, day of the week, trip history, and inputs from the driver of vehicle 10. Step 416: Determine or calculate the outside air temperature (OAT).

[0152] Method 400 determines the outside air temperature, which represents the conditions expected for vehicle 10 during the drive cycle. It should be noted that the outside air temperature may differ from the ambient temperature, particularly when vehicle 10 is parked in a climate-controlled garage. Therefore, the outside air temperature may be determined based on communication networks and weather data. Furthermore, the outside air temperature may be estimated based on the predicted trip start time. For example, controller 16 may connect to the internet to determine what the outside air temperature will be at the start of the upcoming drive cycle—i.e., if it is 1:00 a.m. and the next drive cycle is expected to begin at 7:00 a.m., method 200 will use the expected outside air temperature at 7:00 a.m. Step 418: Predict cabin heating temperature (CHT).

[0153] Method 400 then predicts or estimates the cabin heating temperature that will be requested by the occupants of vehicle 10 during the next drive cycle. For example, controller 16 may determine that the driver will likely set the cabin temperature to approximately 71 degrees Fahrenheit (22 degrees Celsius). Step 420: Is CHT > OAT?

[0154] Method 400 compares the cabin heating temperature with the outside air temperature. This determines whether it is advantageous to store thermal energy in battery 38 to subsequently heat the cabin, or whether ambient conditions will negate the need for additional cabin heating. Step 422: End / Loop.

[0155] If the determination in decision step 420 is negative—i.e., the cabin heating temperature is lower than the outside air temperature—there is little or no need to store thermal energy in battery 38 to heat the cabin. Therefore, method 400 may abort or end. If the outside air temperature is predicted to be higher than the cabin heating temperature, the cabin will likely need to be cooled and at least does not require significant heating from stored thermal energy in battery 38.

[0156] The method 400 may run continuously, so that all steps can occur at any time. Alternatively, the method 400 may run iteratively, e.g., according to a schedule, in a loop. Regardless, when the method 400 reaches the end, the process is likely to repeat as long as any initialization conditions exist. Therefore, after reaching the end / loop step 422, the method may continue back to the start step 410. Step 424: Determine the thermal storage temperature (TST).

[0157] If the determination in decision step 420 is positive—that is, the cabin heating temperature is higher than the outside air temperature—the method 400 has determined that the cabin would benefit from thermal energy stored in the battery 38. Therefore, the method 400 determines a thermal storage temperature for the battery 38. The thermal storage temperature represents a target amount of thermal energy stored in the battery 38 for use in the cabin during the predicted subsequent drive cycle. Step 426: Is the start time later than the loading time?

[0158] Method 400 may determine how and when to generate or add heat energy to battery 38. Therefore, method 400 determines whether the trip start time is later than the time required to charge battery 38. This determines whether method 400 has the ability to delay charging.

[0159] Determining the charging or recharging time may be a function of several current and historical data inputs from the vehicle 10. This is a physics-based calculation specific to at least the battery 38 and the OBCM 36. For example, and without limitation, the controller 16 may calculate the charging time as a function of: state of charge, charging method or maximum charging current, charging efficiency, ambient temperature, driver input, and consumed heater thermal energy.

[0160] As an example, the base charging or recharging time can be calculated by dividing the expected total electrical energy by the average current flow from the charger, so that: Base charging time = electrical energy / average current. If 40kWh of energy is required to reach the target SOC of the battery 38 and the external power source 39 provides an average of 15kW of power, this will take approximately 160 minutes (2 2 / 3 hours).

[0161] In some configurations, the charging time may also be calculated to account for the time required to reach a minimum charging temperature and / or the time required to condition the battery 38 to the thermal storage temperature. The time to heat to the minimum temperature may be a function of the difference between the current and minimum temperatures of the battery 38, the thermal capacity of the battery 38, and the heat transfer and internal heat generation rates.

[0162] Therefore: Time to heat up to minimum temperature = Temperature Δ * (Battery heat capacity * Battery mass) / (Battery heat capacity + Internal heat generation rate). If the temperature of the 38-volt battery needs to be increased by 15 degrees Celsius to reach the minimum charging temperature, this will take between 6 and 7 minutes.

[0163] It should be noted that the controller 16 can also calculate the time required to condition the battery 38 to the thermal storage temperature. The conditioning time is a similar function to the time to minimum temperature (above). Therefore: Conditioning time = Temperature Δ * (Battery thermal capacity * Battery mass) / (Battery thermal capacity + Internal heat generation rate). If the temperature of the battery 38 needs to be increased by 10 degrees Celsius to reach the thermal storage temperature, the conditioning will take between 4 and 5 minutes.

[0164] In step 426, method 400 may compare the time to start to the base charge time, the time to minimum heat-up time, the conditioning time, the sum of all three, or combinations thereof. Other calculations of charge duration or charge time may also be used, as will be appreciated by those skilled in the art. Step 428: Delay charging and heating.

[0165] If the determination in decision step 426 is positive—that is, there is more time until the predicted trip start time than is needed to charge the battery—the method 400 has recognized that it can delay the charging of the battery 38. Therefore, to time the end of the charging time to coincide with the trip start time, the controller 16 can delay the charging process so that the heat energy generated in the battery 38 by the charging process remains in the battery 38 at the start time. An example of this is shown in Fig. 7B.

[0166] It should be noted, however, that before considering heating techniques or timing, the controller 16 may ensure that a sufficient minimum charge is present in the battery 38. For example, even if it would be beneficial to delay the charging time by several hours, the controller may charge the battery 38 to a minimum level. For example, if the battery's state of charge was very low at the end of the previous drive cycle, the controller may increase the state of charge just in case the vehicle 10 is deployed before the predicted trip start time.

[0167] The time elapsed during the charging delay may be adjusted by controller 16 to promote retention of thermal energy in battery 38 while maintaining some margin for error in the predicted trip start time. For example, and without limitation, method 400 may estimate the charging time to be approximately two hours and then begin charging battery 38 approximately three hours before the predicted trip start time. If vehicle 10 is driven early, sufficient thermal energy from the natural charging energy and a sufficient state of charge of battery 38 are likely to be present. Step 430: Charging.

[0168] After the delay period, if any, method 400 begins charging the battery. Generally, the charging period continues until either the battery 38 reaches a target state of charge or the vehicle 10 is disconnected from the external power source 39. Step 432: Heat storage temperature by charging alone?

[0169] After or simultaneously with the initiation of charging of battery 38, method 400 checks whether the thermal storage temperature can be reached due to the natural thermal energy generated during charging. While charging of battery 38 will increase the temperature of battery 38, it may not necessarily increase to the thermal storage temperature that would be preferred to reduce subsequent cabin heating requirements. Step 434: Secondary heating.

[0170] If the determination in decision step 432 is negative—i.e., the charging cycle will not generate sufficient heat energy to bring the battery 38 to the thermal storage temperature—the method 400 has identified that it may require secondary heating to bring the battery 38 to the thermal storage temperature. Therefore, to store sufficient heat energy in the battery 38, the controller 16 may, for example and without limitation, command: resistive heating introduced into the coolant circuit 24, inefficient charging of the battery 38 by the OBCM 36, or cyclic charging and discharging of the battery 38. Step 436: Storing the heat energy in the battery.

[0171] The thermal energy generated by method 400 by charging the battery 38, by secondary heating of the battery 38, or by both, is stored in the battery 38 as a thermal storage device or mass. Step 438: Transferring the heat energy from the battery to the cabin.

[0172] At the start of the trip, method 400 transfers the stored thermal energy of battery 38 to the cabin to increase the temperature of the cabin to the cabin heating temperature. The transfer may occur, for example, and without limitation, via the coolant circuit 24 and the radiator 50 to the HVAC system 78, which acts as a heat pump. The cabin is therefore heated with the thermal energy stored in the battery 38, as opposed to the chemical energy transferred from the battery 38 to a resistive heater or the heat pump, which would reduce the vehicle's range. After transferring the thermal energy of the battery 38 to the cabin for heating, method 400 may proceed to the end / loop step 422.

Claims

[1] A method (400) for managing the thermal energy of a battery (38) in a vehicle (10) having an electric drive system, comprising: Monitoring a current battery temperature after the vehicle (10) has been connected to an external power source (39) at a connection time (312, 342, 372); Determining (416) an outside air temperature (172); predicting (418) a cabin heating temperature for a subsequent drive cycle, wherein the subsequent drive cycle occurs when the vehicle (10) is no longer connected to the external power source (39); if the predicted cabin heating temperature is greater than the outside air temperature (172), heating the battery (38) to a heat storage temperature (348) that is greater than a target operating temperature of the battery (38) such that heat energy is stored in the battery (38); Predicting a trip start time (325), wherein the trip start time (325) occurs after the vehicle (10) has been disconnected from the external power source (39); Determining a charging time between a start of charging and a end of charging (314) at which the battery (38) reaches a substantially full state of charge; if the start of the journey time (325) is later than the charging time, delaying the start of charging until after the connection time (312, 342, 372); Commencing charging so that the charging duration is at least 80% of the time elapsed before the predicted trip start time (325); and Transferring the thermal energy stored in the battery (38) into a cabin of the vehicle (10) after the start of the journey (325). [2] The method (400) of claim 1, wherein heating the battery (38) to the heat storage temperature (348) occurs while the battery (38) is being charged from the external power source (39). [3] The method (400) of claim 2, wherein heating occurs only when the heat storage temperature (348) and the cabin heating temperature are both higher than the outside air temperature (172). [4] The method (400) of claim 1, further comprising: Generating heat energy with a resistance heater or with a heat pump while the vehicle (10) is connected to the external power source (39); and Circulating the generated heat energy to the battery (38) so that the heat storage temperature (348) is greater than a natural charging temperature (340). [5] A vehicle (10) with an electric drive system, comprising: a battery (38); and a controller (16) operatively connected to the battery (38), the controller (16) being configured to: monitor a current battery temperature after the vehicle (10) has been connected to an external power source (39) at a connection time (312, 342, 372); to determine an outside air temperature (416); predict (418) a cabin heating temperature of the vehicle (10) for a subsequent drive cycle, the subsequent drive cycle occurring when the vehicle (10) is no longer connected to the external power source (39); if the predicted cabin heating temperature is greater than the outside air temperature (172), heat the battery (38) to a heat storage temperature (348) that is greater than a target operating temperature of the battery (38) so that heat energy is stored in the battery (38), wherein the heating of the battery (38) to the heat storage temperature (348) occurs while the battery (38) is being charged from the external power source (39); to transfer the thermal energy stored in the battery (38) into a cabin of the vehicle (10); predict a trip start time (325), wherein the trip start time (325) occurs after the vehicle (10) is disconnected from the external power source (39); calculate a charging time between a charging start and a charging stop (314) that occurs when the battery (38) reaches a substantially full state of charge; to delay the start of charging until after the connection time (312, 342, 372) if the start of the journey time (325) is later than the charging time; and to start charging in such a way that the charging time is at least 80% of the time before the expected start time of the journey (325). [6] The vehicle (10) of claim 5, wherein the controller (16) is further configured to: to heat the battery (38) only when both the heat storage temperature (348) and the cabin heating temperature are higher than the outside air temperature (172). [7] The vehicle (10) of claim 5, wherein the controller (16) is further configured to calculate the charging time to include: a base charging time during which the battery (38) is brought to a target charging state; a heating time to a minimum charging temperature during which the battery (38) is brought to a minimum charging temperature for charging; and a conditioning time during which the battery (38) is heated by a resistance heater or a heat pump. [8] The vehicle (10) of claim 5, wherein the controller (16) is further configured to: to generate thermal energy with a resistance heater or a heat pump while the vehicle (10) is connected to the external power source (39); and to circulate the generated heat energy to the battery (38) so that the heat storage temperature (348) is greater than a natural charging temperature (340).

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