Method, controller and electric vehicle for non-uniform battery heating of traction battery

Abstract

A method (500) performed by an electric vehicle controller (210) in which a vehicle (100) has a plurality of battery packs (110a, 110b, 110c, 110d), each having its own heating device (230) to individually adjust the respective battery pack temperature. The method (500) includes detecting when a temperature of the battery pack (110a, 110b, 110c, 110d) falls below a specified lower threshold level. Upon detection, the heating device (230) is allowed to provide heat to a different first set (105) of battery packs while not allowed to provide heat to a separate second set (107) of battery packs. This selective heating strategy occurs when it is found that the battery temperature is below the lower threshold level. A corresponding controller (210) and an electric vehicle (100) are also described.

Description

TECHNICAL FIELD

[0001] This document discloses a method, a controller, a computer program, a computer program product and an electric vehicle. The electric vehicle comprises a plurality of battery packs, each associated with a heating device. The heating devices are configured to individually adjust the temperature of each respective battery pack. The method comprises detecting a battery temperature of a battery pack below a lower threshold level. The method further comprises allowing the heating devices to provide heat to a first set of battery packs while not allowing the heating devices to provide heat to a second set of battery packs when the battery temperature is detected below the lower threshold level. BACKGROUND

[0002] Vehicles with electric propulsion systems comprise rechargeable traction batteries. In the case of heavy electric vehicles, such as trucks, buses, etc., the propulsion of the vehicle often requires multiple traction battery packs. These traction battery packs can be arranged in series and / or in parallel to provide the necessary voltage / power performance. In addition, for the case of the weight distribution and driving characteristics of the vehicle, the battery packs are often distributed at different distinct locations of the heavy vehicle due to the relative weight of the battery packs.

[0003] By introducing traction battery packs for the propulsion of the vehicle instead of combustion engines, various attractive advantages are realized, such as less pollution / emission of carbon dioxide and / or nitrous oxide, less noise from the vehicle during propulsion, reduced operating costs (for fuel), and / or reduced maintenance / repair costs compared to vehicles with internal combustion engines.

[0004] However, despite the many advantages of the concept of electric vehicles and the relatively long time of technical development in this field, the large-scale implementation of heavy electric vehicles has not yet been realized. One reason is the problem of low battery performance at low temperatures.

[0005] A disadvantage of traction battery packs compared to combustion engines is that, in addition to the state of charge (SOC) level, the performance of the battery pack also depends on the temperature of the battery pack. The low-temperature power performance of traction battery packs for electric vehicles is very limited and can often be below the minimum power requirement in arctic / sub-arctic regions in winter, for example at temperatures below -10°C.

[0006] Behind this performance drop of traction battery packs at low temperatures is an electrochemical reason, partly due to an increase in internal resistance, which reduces the available current from the battery pack.

[0007] This is a problem that mainly occurs when a cold battery pack is utilized to start the vehicle and during the first period after starting, because the temperature of the battery pack will gradually increase (due to the internal resistance) during use.

[0008] A known solution to this problem is to apply a heater to the battery pack and heat the battery pack, preferably before starting the vehicle, while the vehicle is plugged into a battery charger to charge the battery pack. Thereby, both the SOC level and the temperature of the battery pack increase, while the internal resistance decreases. Another possible solution is to park the vehicle indoors in a heated garage during the night or during breaks.

[0009] However, these known solutions can not be available to the vehicle, for example when operating in remote, unpopulated inland areas or when forced to make unscheduled stops. For example, a planned battery charger can be occupied or not functioning.

[0010] In case the driver / vehicle finds him / herself without external power supply to the vehicle, the possible solution available to him / her is to use the battery power supply to run a heater for the battery pack. The battery pack of a heavy vehicle is relatively large and heavy, i.e. involves a high thermal mass. Thus, heating the vehicle battery pack takes time and can deplete the battery pack faster than the battery pack is heated, thus falling into a vicious circle.

[0011] It appears that, in order to achieve a practical implementation of a vehicle with an electric propulsion system, further development is needed, at least in the Arctic / sub-Arctic climate zone, to provide a solution to the problems discussed above. SUMMARY

[0012] It is an object of the present invention to solve or alleviate at least some of the above-mentioned problems and to improve the low temperature performance of an electric vehicle.

[0013] According to a first aspect of the present invention, the object is achieved by a method performed by a controller of an electric vehicle. The vehicle comprises a plurality of battery packs, each associated with a heating device. A battery pack can be referred to as a module or a subset of the total electrical quantity storage device on an electric vehicle for providing electrical power on request to on-board electrical power consumers, for example for propulsion of the electric vehicle. Other terms that can be used for a battery pack can be, for example, battery, traction battery, electric vehicle battery, battery cell, battery module, power pack.

[0014] Regardless of the terminology, at least some of the battery packs or subsets of battery packs are placed at physically different parts of the vehicle in order to distribute the weight of the battery packs over the vehicle for improving or at least not affecting the driving characteristics of the vehicle.

[0015] The heating devices are configured to individually adjust the temperature of each respective battery pack. The method comprises detecting a battery temperature below a lower threshold level in all battery packs, i.e. detecting that all battery packs have a battery temperature below a lower threshold level.

[0016] In case one or some of the battery packs have a temperature exceeding the lower threshold level, this / these battery pack(s) can be selected for vehicle propulsion, since this / these battery pack(s) has / have a lower internal resistance and thus a higher power output than the battery packs having a temperature below the lower threshold level.

[0017] However, in case all battery packs have a detected temperature below the lower threshold level, the heating arrangement is allowed to provide heat to a first set of battery packs in the plurality of battery packs, while the heating arrangement is not allowed to provide heat to a second set of battery packs in the plurality of battery packs. The first set of battery packs is different from the second set of battery packs.

[0018] Thereby, a heating strategy is disclosed, which focuses on uneven heating of the battery packs of the vehicle in order to create a temperature difference between the battery packs. The strategy is that the heater provides heating to only one or a few battery packs, instead of heating all on-board battery packs.

[0019] By using this method, the temperature of one or a few battery packs can be raised quickly compared to when all battery packs are heated at the same time. Compared to previously known solutions, the time taken to reach a higher or at least satisfactory amount of power at very low temperatures after a cold start of the heavy vehicle is minimized or at least reduced. High power operations can be performed earlier after a cold start, thereby prolonging the normal running time of the vehicle at sub-zero temperatures. Another advantage is that the requirements on the heater can be relaxed without compromising the performance of the vehicle, resulting in a cheaper and cost-efficient design. In addition, the requirements on the minimum number of battery packs or the low temperature performance specification of the battery packs can be relaxed without compromising the performance of the vehicle.

[0020] Optionally, the method according to the first aspect can comprise monitoring the cell temperature of the battery packs comprised in the first set of battery packs when the heating arrangement has been allowed to provide heat to the first set of battery packs. In addition, the method can comprise disallowing the heating arrangement to provide heat to the first set of battery packs and allowing the heating arrangement to provide heat to the second set of battery packs when the monitored cell temperature of the battery packs in the first set of battery packs exceeds the upper threshold level.

[0021] When the temperature of the first set of battery packs has reached the upper threshold level, the output power performance of the first set of battery packs increases to a level allowing power output according to the demand of the electric vehicle as a result of internal resistance reduction with increasing temperature. In case of very cold battery packs, the critical phase during cold start launch is ended. The second set of battery packs is heated by diverting the focus, the capacity in terms of available power output of these battery packs is increased.

[0022] Optionally, the method according to the first aspect can comprise estimating a state of charge (SOC) of each respective battery pack. The method can further comprise adjusting the lower threshold level and / or the upper threshold level of the battery temperature based on the estimated SOC.

[0023] The output power capacity of the battery packs deteriorates with decreasing temperature, but is also affected by decreasing SOC. By adjusting the lower threshold level and / or the upper threshold level of the battery temperature by taking the estimated SOC into account, a better precision in achieving a certain required power requirement of the electric vehicle is provided.

[0024] Optionally, the lower threshold level and / or the upper threshold level of the battery temperature can be adjusted based on the power requirement of the vehicle and / or the available power in the first set of battery packs.

[0025] By adjusting the lower threshold level and / or the upper threshold level of the battery temperature by taking the power requirement of the vehicle and / or the available power in the first set of battery packs into account, an efficient heating of the battery packs is provided.

[0026] Optionally, the battery packs comprised in the first set of battery packs and / or the second set of battery packs can be selected for equally distributing the selection over time based on historical data of previous made selections.

[0027] By equally distributing the selection of battery packs comprised in the first set of battery packs and / or the second set of battery packs, the aging of the battery packs in the electric vehicle is evenly distributed, which is advantageous from a technical lifetime perspective of the vehicle.

[0028] Optionally, the first set of battery packs and the second set of battery packs can constitute all battery packs of the vehicle.

[0029] According to a second aspect of the present invention, the object is achieved by a controller of an electric vehicle managing a plurality of battery packs within the vehicle. Each battery pack is associated with a heating device designed to individually adjust the temperature of each respective battery pack. The controller is configured to detect, using temperature sensors, that the battery temperature for all battery packs is below a lower threshold level. When detecting that the battery temperature is below the lower threshold level, the controller allows the heating devices to provide heat to a first set of battery packs among the plurality of battery packs while preventing the heating devices from providing heat to a second set of battery packs among the plurality of battery packs. The first set of battery packs is different from the second set of battery packs.

[0030] Thereby, the available power of the battery packs is focused on heating a limited number of battery packs of the vehicle, rather than spreading the available battery power to heat all battery packs at the same time as in prior art solutions. The time taken to heat the limited number of battery packs of the vehicle to operating temperature is reduced, where the battery packs have low / lower internal resistance and thus high power output.

[0031] Optionally, the controller can be configured to monitor, via the temperature sensors, the battery temperature of the battery packs included in the first set of battery packs. In addition, the controller can be configured to, when the monitored battery temperature of the battery packs in the first set of battery packs exceeds an upper threshold level, not allow the heating devices to provide heat to the first set of battery packs and allow the heating devices to provide heat to the second set of battery packs.

[0032] When the temperature of the first set of battery packs has reached the upper threshold level, the output power performance of the first set of battery packs is increased to a level of power allowed to be output according to the demands of the electric vehicle as a result of the internal resistance reduction with increasing temperature. In case of very cold battery packs, the critical phase at the beginning of the cold start launch is ended. By shifting the focus to heat the second set of battery packs, the capacity in terms of available power output of these battery packs is increased.

[0033] Optionally, the controller can also be configured to estimate the SOC of each respective battery pack. The controller can be additionally configured to adjust the lower threshold level and / or the upper threshold level of the battery temperature based on the estimated SOC.

[0034] The output power capacity of the battery packs deteriorates with decreasing temperature, but is also affected by decreasing SOC. By adjusting the lower threshold level and / or the upper threshold level of the battery temperature by taking the estimated SOC into account, a better precision is provided in achieving a certain required power requirement of the electric vehicle.

[0035] Optionally, the lower threshold level and / or the upper threshold level of the battery temperature can be adjusted by the controller based on the power requirements of the vehicle and / or the available power in the first set of battery packs.

[0036] By adjusting the lower threshold level and / or the upper threshold level of the battery temperature by taking into account the power requirements of the vehicle and / or the available power in the first set of battery packs, an efficient heating of the battery packs is provided.

[0037] Optionally, the controller can be configured to select the battery packs comprised in the first set of battery packs and / or the second set of battery packs for the selection to be equally distributed in time based on historical data of previous selections.

[0038] By equally distributing the selection of battery packs comprised in the first set of battery packs and / or the second set of battery packs, the aging of the battery packs in the electric vehicle is evenly distributed, which is advantageous from a technical lifetime perspective of the vehicle.

[0039] According to a third aspect of the present invention, the object is achieved by an electric vehicle comprising a number of battery packs, each associated with a heating device designed to individually adjust the temperature of each respective battery pack. The vehicle is further equipped with a controller according to the second aspect and a temperature sensor communicatively connected to the controller.

[0040] Thereby, an electric vehicle is provided which is able to operate with the required power after a minimum or at least reduced heating time, also when starting the vehicle with cold batteries. Thus, electric heavy-duty vehicles can be used in winter in arctic / sub-arctic climate zones or other environments with cold temperatures without loss of operational capabilities. Optionally, the heating device can comprise a battery heater configured to heat a fluid. The heating device can further comprise a plurality of heat exchangers each configured to raise the temperature of one respective battery pack. The heating device can additionally comprise a pipe connected to the battery heater, the pipe being structured to convey the heated fluid from the battery heater to the heat exchangers. The heating device can further comprise a plurality of fluid regulators each communicatively connected to the controller and structured to allow or not allow the heated fluid from the pipe to reach the respective heat exchanger.

[0041] Thereby, a convenient solution for uneven heating of the battery packs is provided.

[0042] Optionally, the heating device can comprise a plurality of battery heaters each communicatively connected to the controller and configured to raise the temperature of one respective battery pack.

[0043] Thereby an alternative solution for uneven heating of the battery packs is provided.

[0044] According to a fourth aspect of the application, the object is achieved by a computer program comprising program code for performing the method according to the first aspect when the computer program is executed in the controller according to the second aspect.

[0045] According to a fifth aspect of the application, the object is achieved by a computer readable medium comprising instructions which, when executed by the controller according to the second aspect, cause the controller to carry out the steps of the method according to the first aspect.

[0046] Thereby, a heating strategy is disclosed which focuses on uneven heating of the battery packs of the vehicle in order to create a temperature difference between the battery packs. The strategy is to provide heating by the heater to only one or a few battery packs instead of heating all on-board battery packs.

[0047] By maintaining the temperature of the first set of propulsion battery packs within the optimal range, the performance, efficiency and lifetime of the battery packs are ensured, thereby extending the driving range and total lifetime of the vehicle.

[0048] Other advantages and additional novel features will become apparent from the following detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0049] Embodiments of the present application will now be described in further detail with reference to the drawings, in which:

[0050] Figure 1 A side view of a vehicle with a plurality of battery packs is illustrated;

[0051] Figure 2A An embodiment of an electric propulsion arrangement in an electric vehicle with a plurality of battery packs and a heating device is illustrated;

[0052] Figure 2B An embodiment of an electric propulsion arrangement in an electric vehicle with a plurality of battery packs and a heating device is illustrated;

[0053] Figures 3A-3B A comparison of normalized output power of battery packs at different temperatures and state of charge is illustrated;

[0054] Figures 4A-4B A comparison of normalized internal resistance of battery packs at different temperatures and state of charge is illustrated;

[0055] Figure 5 is a flow chart illustrating an embodiment of a method. DETAILED DESCRIPTION

[0056] Embodiments of the application described herein are defined as methods, controllers, computer programs, computer readable media, and electric vehicles that can be practiced in the embodiments described below. These embodiments may, however, be exemplified in many different forms and are not limited to the examples set forth herein; rather these illustrative examples of embodiments are provided so that the present disclosure will be thorough and complete.

[0057] Other objects and features can become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the embodiments disclosed herein, which are to be

[0058] Figure 1 A scenario is illustrated in which a vehicle 100 is driving on a road 101. The vehicle 100 comprises a plurality of chargeable battery packs 110a, 110b, 110c, 110d, i.e. at least two battery packs 110a, 110b, 110c, 110d. The battery packs 110a, 110b, 110c, 110d can be charged, e.g. during standstill, at a charging station via an inductive coil in / under the road 101 and / or via a conductive transmission from an overhead energy transfer segment, e.g. via a roof-mounted pantograph. In some possible embodiments, when the vehicle 100 is decelerating or braking, energy generated by a regenerative braking system can be fed back into the battery packs 110a, 110b, 110c, 110d, thereby recharging these battery packs.

[0059] The term “battery pack” is herein to be understood to include a high-capacity energy storage system of a plurality of individual battery cells in series configuration and parallel configuration. These battery cells can for example be lithium-ion based, as lithium-ion batteries provide high energy density, long cycle life, and relatively low self-discharge. However, some other examples of battery cells can include lead-acid, nickel-cadmium, nickel-metal hydride. In other literature, other terms sometimes used for the term “battery pack” can be e.g. battery, traction battery, electric vehicle battery, battery cell, battery module, power pack, etc.

[0060] The battery packs 110a, 110b, 110c, 110d store and release electrical energy to drive one or several electric motors, which in turn propel the vehicle 100. During acceleration, the battery packs 110a, 110b, 110c, 110d release energy, thereby providing electric power to the motors.

[0061] The vehicle 100 can be any kind of transportation vehicle that requires and includes a plurality of battery packs 110a, 110b, 110c, 110d for meeting its operational requirements for power and range. These battery packs 110a, 110b, 110c, 110d are arranged in series and / or in parallel to provide the necessary voltage / power performance. Some examples of such vehicles 100 can be, for example, trucks, buses, vans, mining vehicles, railway vehicles, trams, agricultural vehicles, excavators, military vehicles / tanks, unmanned aerial vehicle systems, drones, snowmobiles, mobile robots, ships, submarines, hovercrafts, airplanes, helicopters, spaceships, extraterrestrial rovers, satellites, cruise missiles, rockets, or similar vehicles.

[0062] For example, the vehicle 100 can be configured for operation on roads, on ground, on tracks, on construction sites, or in mines; alternatively in water / underwater, on snow, on ice, in air, in space, on extraterrestrial ground, etc.

[0063] In different embodiments, the vehicle 100 can be a driver-controlled or an autonomous-controlled vehicle. However, for improved clarity, the vehicle 100 is subsequently described as a ground vehicle with a driver.

[0064] The battery packs 110a, 110b, 110c, 110d of the vehicle 100 are organized into at least a first set 105 of battery packs 110a, 110b, 110c, 110d and a second set 107 of battery packs 110a, 110b, 110c, 110d, wherein the first set 105 of battery packs 110a, 110b, 110c, 110d is different from the second set 107 of battery packs 110a, 110b, 110c, 110d. Each of the first set 105 of battery packs 110a, 110b, 110c, 110d and the second set 107 of battery packs 110a, 110b, 110c, 110d can include one single battery pack 110a, 110b, 110c, 110d or several battery packs 110a, 110b, 110c, 110d.

[0065] In cold starts, especially at sub-zero temperatures, the time required to boost the available power to a sufficient level is a key characteristic of the product. For example, at -10°C, the available power from the battery packs 110a, 110b, 110c, 110d is several times lower than the power available at 10°C (a non-limiting example of temperature). Therefore, when the battery packs 110a, 110b, 110c, 110d are at sub-zero temperatures, the power delivered by the battery packs 110a, 110b, 110c, 110d is limited.

[0066] To minimize the time it takes to reach sufficient power (for normal operation) when cold starting the heavy electric vehicle 100, the solution to this problem is to provide uneven heating of the battery packs 110a, 110b, 110c, 110d by limiting the heating to one set 105 of battery packs 110a, 110b, 110c, 110d. The set 105 of battery packs 110a, 110b, 110c, 110d can comprise one single battery pack 110a, 110b, 110c, 110d or several battery packs 110a, 110b, 110c, 110d.

[0067] Hereby, the available power of the battery packs 110a, 110b, 110c, 110d is focused on heating a limited number of battery packs 110a, 110b, 110c, 110d of the vehicle 100, instead of spreading the available battery power to heat all battery packs 110a, 110b, 110c, 110d at the same time as in prior art solutions. Hereby, the time it takes to heat a limited number of battery packs 110a, 110b, 110c, 110d of the vehicle 100 to operating temperature is reduced, where the battery packs 110a, 110b, 110c, 110d have low / relatively low internal resistance and thus high power output.

[0068] The method for implementing this solution is explained in Figure 5 and discussed in the corresponding chapter of the description. Figures 4A-4B The relationship between the internal resistance of the battery packs 110a, 110b, 110c, 110d and the temperature at some different SOC is explained in Figures 3A-3B and the relationship between the power of the battery packs 110a, 110b, 110c, 110d and the temperature at some different SOC is explained in

[0069] As examples of respective embodiments, the Figures 2A-2B The electric vehicle 100 comprises a system 200 for battery management and monitoring, as explained in

[0070] The battery packs 110a, 110b, 110c, 110d power various electric power consuming components 220 of the vehicle 100, such as electric motors for propulsion, heaters of the driver cabin, headlamps, etc.

[0071] The controller 210 also performs thermal management of the battery packs 110a, 110b, 110c, 110d by controlling and adjusting the temperature of the battery packs 110a, 110b, 110c, 110d via the heating devices 230.

[0072] The heating devices 230 are configured to individually adjust the temperature of each respective battery pack 110a, 110b, 110c, 110d. Thereby, in scenarios where the temperature is very low, such as below a lower threshold level, it becomes possible to focus on heating only one battery pack 110a, 110b, 110c, 110d or a set 105 of battery packs 110a, 110b, 110c, 110d.

[0073] An optimal temperature range for the battery packs 110a, 110b, 110c, 110d can be estimated to be about 20°C and 40°C for ensuring optimal power performance, safety, and lifetime of the battery packs 110a, 110b, 110c, 110d.

[0074] The concept of the present solution focuses on the specific situation when the vehicle 100 has been parked outdoors or in an unheated garage (or the temperature of the battery packs 110a, 110b, 110c, 110d has dropped below a lower threshold level for other reasons).

[0075] The journey of a professional heavy-duty vehicle 100 is typically pre-planned; in addition, the charging and heating management of the battery packs 110a, 110b, 110c, 110d is typically planned, which is the reason why a temperature of the battery packs 110a, 110b, 110c, 110d below a lower threshold level is only expected in exceptional situations, e.g. in case of an emergency stop or similar. The typical way of heating the battery packs 110a, 110b, 110c, 110d during parking is naturally to charge the battery packs 110a, 110b, 110c, 110d at a charging station and / or to use the power from the charging station to operate the heating devices 230 to heat all battery packs 110a, 110b, 110c, 110d, thereby maintaining these battery packs above the lower threshold level and possibly preferably within the optimal temperature range.

[0076] The controller 210 is configured to detect, via the temperature sensors 240a, 240b, 240c, 240d, that the battery temperature in all battery packs 110a, 110b, 110c, 110d is below a lower threshold level. In some embodiments, one respective temperature sensor 240a, 240b, 240c, 240d can be arranged at each battery pack 110a, 110b, 110c, 110d for enabling continuous monitoring of the battery temperature. Alternatively, however, the controller 210 can estimate that the temperature of all battery packs 110a, 110b, 110c, 110d is below the lower threshold level, e.g. when the vehicle 100 has been parked outside in a cold ambient temperature for longer than a certain time period, e.g. without being connected to a charging station, as can be estimated based on various sensors.

[0077] The controller 210 is further configured to, when detecting that the battery temperature is below the lower threshold level, allow the heating arrangement 230 to provide heat to a first set 105 of battery packs 110a, 110b, 110c, 110d among the plurality of battery packs 110a, 110b, 110c, 110d in the vehicle 100. At the same time, the controller 210 does not allow the heating arrangement 230 to provide heat to a second set 107 of battery packs 110a, 110b, 110c, 110d among the plurality of battery packs 110a, 110b, 110c, 110d in the vehicle 100. The first set 105 of battery packs 110a, 110b, 110c, 110d is different from the second set 107 of battery packs 110a, 110b, 110c, 110d.

[0078] The lower threshold level of the battery temperature can be set to a temperature within an interval between, e.g., -20°C and 10°C, such as, e.g., about -10°C, about 0°C, or some temperature therebetween.

[0079] In some embodiments, the lower threshold level of the battery temperature, as well as the upper threshold level, can be adjusted by the controller 210, e.g. based on an estimated SOC of the respective battery packs 110a, 110b, 110c, 110d; and / or based on power requirements of the vehicle 100 and / or available power in the first set 105 of battery packs 110a, 110b, 110c, 110d.

[0080] The controller 210 is further configured to select the battery packs 110a, 110b, 110c, 110d to be included in the first set 105 of battery packs 110a, 110b, 110c, 110d and / or the second set 105 of battery packs 110a, 110b, 110c, 110d based on historical data of previous selections made.

[0081] An advantage resulting herefrom is that the ageing of the battery packs 110a, 110b, 110c, 110d is thereby evenly distributed among the battery packs 110a, 110b, 110c, 110d.

[0082] The controller 210 can further be configured to monitor, via the temperature sensors 240a, 240b, 240c, 240d, the battery temperatures of the battery packs 110a, 110b, 110c, 110d comprised in the first set 105 of battery packs 110a, 110b, 110c, 110d when an uneven distribution of heat has been provided to the battery packs 110a, 110b, 110c, 110d during propulsion of the vehicle 100.

[0083] Further, the controller 210 can be configured to not allow the heating arrangement 230 to provide heat to the first set 105 of battery packs 110a, 110b, 110c, 110d when the monitored battery temperatures of the battery packs 110a, 110b, 110c, 110d in the first set 105 of battery packs 110a, 110b, 110c, 110d exceeds an upper threshold level, and to allow the heating arrangement 230 to provide heat to the second set 107 of battery packs 110a, 110b, 110c, 110d.

[0084] The upper threshold level can be set to a temperature within an interval of, for example, between 0°C and 20°C, such as, for example, about 5°C, about 10°C, or about 15°C, or some temperature therebetween. As already stated above, the upper threshold level, as well as the lower threshold level, can be dynamically adjusted based on, for example, the estimated SOC of the respective battery pack 110a, 110b, 110c, 110d; and / or based on the power requirements of the vehicle 100 and / or the available power in the first set 105 of battery packs 110a, 110b, 110c, 110d.

[0085] The vehicle 100, i.e. the system 200, can further comprise a respective switch 250a, 250b, 250c, 250d for each battery pack 110a, 110b, 110c, 110d. Each of the switches 250a, 250b, 250c, 250d can be communicatively connected to the controller 210. Thereby, in some embodiments, the controller 210 is able to disconnect the power output of one or several battery packs 110a, 110b, 110c, 110d, such as for example the cold battery packs 110a, 110b, 110c, 110d, i.e. the battery packs 110a, 110b, 110c, 110d not comprised in the heated first set 105 of battery packs 110a, 110b, 110c, 110d. Thus, in some embodiments, only the warmer or heated first set 105 of battery packs 110a, 110b, 110c, 110d is available for propelling the vehicle 100 as well as for other power consuming components 220 and the heating device 230.

[0086] As Figure 2A The heating device 230 comprises, as explained in the background section, a battery heater 231 configured to heat a fluid, which can comprise a liquid sometimes referred to as coolant (water / glycol mixture) or a gas such as air. The battery heater 231 can comprise an electric heating element providing resistive heating or possibly a heat pump. The warmed fluid can be provided via a pipe 232 to a respective heat exchanger 234a, 234b, 234c, 234d associated with each individual battery pack 110a, 110b, 110c, 110d. The heated fluid thereby transfers heat to the respective battery pack 110a, 110b, 110c, 110d and the cooled fluid is circulated back to the battery heater 231.

[0087] Each heat exchanger 234a, 234b, 234c, 234d can be associated with a respective fluid regulator 233a, 233b, 233c, 233d, which can be communicatively connected to the controller 210. The fluid regulator 233a, 233b, 233c, 233d can comprise for example a valve or a pump.

[0088] The controller 210 is configured to allow / disallow circulation of heated fluid to the battery packs 110a, 110b, 110c, 110d by opening / closing the respective fluid regulators 233a, 233b, 233c, 233d, thereby allowing circulation of heated fluid to the battery packs 110a, 110b, 110c, 110d in the first set 105 of battery packs 110a, 110b, 110c, 110d while disallowing circulation of heated fluid to the battery packs 110a, 110b, 110c, 110d in the second set 107 of battery packs 110a, 110b, 110c, 110d.

[0089] The heat exchangers 234a, 234b, 234c, 234d of the battery packs 110a, 110b, 110c, 110d that are desired to be heated are thereby provided with heated fluid from the battery heaters 231 via the pipes 232. The heated fluid is then allowed to circulate through the battery packs 110a, 110b, 110c, 110d that are desired to be heated to raise their temperature.

[0090] Thereby, efficient heating of the battery packs 110a, 110b, 110c, 110d is provided, thereby providing precise temperature control of the battery packs 110a, 110b, 110c, 110d.

[0091] As Figure 2B The heating arrangement 230 comprises a plurality of battery heaters 231a, 231b, 231c, 231d that are each communicatively connected to the controller 210 and configured to raise the temperature of one respective battery pack 110a, 110b, 110c, 110d, as explained in the background section.

[0092] Each of the battery heaters 231a, 231b, 231c, 231d can comprise electric heating elements, such as resistive wires or flexible heating pads, that are placed in contact with or embedded within the corresponding respective battery pack 110a, 110b, 110c, 110d. When an electric current passes through the heating elements, these heating elements generate heat that is then transferred to the battery pack 110a, 110b, 110c, 110d.

[0093] Each of the battery heaters 231a, 231b, 231c, 231d can be communicatively connected to the controller 210 and configured to raise the temperature of one respective battery pack 110a, 110b, 110c, 110d.

[0094] The controller 210 can thus be configured to allow heating of the battery packs 110a, 110b, 110c, 110d in the first set 105 of battery packs 110a, 110b, 110c, 110d by activating / deactivating the corresponding battery heater 231a, 231b, 231c, 231d, while not allowing circulation of the heated fluid to the battery packs 110a, 110b, 110c, 110d in the second set 107 of battery packs 110a, 110b, 110c, 110d.

[0095] The resistive heating of the battery packs 110a, 110b, 110c, 110d by the respective battery heater 231a, 231b, 231c, 231d is easy to implement and reliable.

[0096] Figure 3A And Figure 3B Some examples of the variation of the (normalized) available power and internal resistance for a specific battery cell chemistry across different battery temperatures at different SOC levels are schematically illustrated.

[0097] The available power from a battery depends to a large extent on the temperature and state of charge (SOC level) of the battery pack 110a, 110b, 110c, 110d. Therefore, the electric vehicle 100 is equipped with a BMS 200 and a controller 210 that can monitor the temperature of the battery packs 110a, 110b, 110c, 110d via temperature sensors 240a, 240b, 240c, 240d and the heating of the first set 105 of battery packs 110a, 110b, 110c, 110d for optimal power performance.

[0098] As Figure 3A illustrated in the middle, for 10% SOC, the available power of the battery packs 110a, 110b, 110c, 110d is very low at cold temperatures. In contrast, at temperatures below -10°C or around, the (normalized in the graph) available power is very low and the increase of the available power with increasing temperature is low. Between -10°C and about 0°C, the available power increases slightly faster, but still quite moderate. At battery temperatures above 0°C, the available power increases rapidly with increasing temperature.

[0099] Figure 3B The available power of the battery packs 110a, 110b, 110c, 110d at 35% SOC is illustrated. The available power increases substantially linearly with increasing temperature.

[0100] The lower threshold level of the battery temperature can be set to a temperature within an interval between, for example, -20°C and 10°C, such as, for example, about -10°C, about 0°C, or some temperature therebetween. The upper threshold level of the battery temperature can correspondingly be set to a temperature within an interval between, for example, 0°C and 20°C, such as, for example, about 5°C, about 10°C, or about 15°C, or some temperature therebetween.

[0101] The lower threshold level and / or the upper threshold level of the battery temperature for triggering the method in question can be set dynamically based on, for example, the estimated SOC of the respective battery pack 110a, 110b, 110c, 110d; and / or on the power requirements of the vehicle 100 and / or the available power in the first set 105 of battery packs 110a, 110b, 110c, 110d.

[0102] Figures 4A-4B The internal resistance of the battery packs 110a, 110b, 110c, 110d in the vehicle 100 and the dependence of this internal resistance on temperature at different SOCs are illustrated.

[0103] The internal resistance herein refers to the opposition to the flow of current within the battery pack 110a, 110b, 110c, 110d. This opposition is a combined effect of various factors, including the resistance of the battery electrodes, the electrolyte, and the power receiver. The internal resistance plays a crucial role in determining the performance, efficiency, and lifespan of the battery pack 110a, 110b, 110c, 110d.

[0104] The internal resistance can vary depending on the temperature and SOC of the respective battery pack 110a, 110b, 110c, 110d.

[0105] Generally, as the temperature of the battery pack 110a, 110b, 110c, 110d increases, the internal resistance of that battery pack decreases. Higher temperatures improve the conductivity of the electrolyte and the electrode reactions, resulting in a decreased internal resistance. Low temperatures slow down the electrode reactions and reduce the conductivity of the electrolyte, which increases the internal resistance and reduces the performance and available power output of the battery pack 110a, 110b, 110c, 110d.

[0106] As can be seen in connection with the Figure 4B Investigations Figure 4A As can be seen, the internal resistance of the battery pack 110a, 110b, 110c, 110d also varies depending on its SOC. Generally, the internal resistance is higher when the battery pack 110a, 110b, 110c, 110d is at a low SOC, and lower when the battery pack is at a high SOC. This is because, at lower SOCs, the available surface area for electrochemical reactions is reduced, and the electrolyte concentration is less favorable, resulting in an increased internal resistance.

[0107] Thanks to the provided solution, by monitoring the temperature of the battery packs 110a, 110b, 110c, 110d and in some embodiments also the SOC, the internal resistance can be reduced by adjusting the battery temperature of the selected first set 105 of battery packs 110a, 110b, 110c, 110d for maintaining optimal performance and prolonging battery life.

[0108] Figure 5 An example of a method 500 according to an embodiment is illustrated. Figure 5 The flowchart in Fig. 1 illustrates a method 500 performed by a controller 210 of an electric vehicle 100. The electric vehicle 100 comprises a plurality of battery packs 110a, 110b, 110c, 110d, each associated with a heating device 230 configured to individually adjust the temperature of each respective battery pack 110a, 110b, 110c, 110d.

[0109] The electric vehicle 100 can be a heavy-duty vehicle for professional transport, such as for example an articulated truck-trailer combination, a bus, a truck, a van, etc. or any of the previously exemplified vehicles.

[0110] In order to be able to correctly individually / separately adjust the temperature of each of the battery packs 110a, 110b, 110c, 110d of the vehicle 100, the method 500 can comprise a number of steps 501-506. However, some of these steps 501-506 can be performed individually in some alternative embodiments, such as for example steps 501-502 or steps 505-506. Furthermore, the described steps 501-506 can be performed in a slightly different chronological order than the one implied by the numbering. The method 500 can comprise subsequent steps:

[0111] A step 501, which can be performed in some alternative embodiments, comprises estimating the SOC of each respective battery pack 110a, 110b, 110c, 110d.

[0112] The SOC of the battery packs 110a, 110b, 110c, 110d can be estimated by the controller 210 based on one or a combination of methods in the method such as voltage-based estimation, coulomb counting, impedance spectroscopy, model-based estimation, and / or machine learning and data-driven methods.

[0113] Voltage-based estimation: The battery voltage is generally related to the SOC, as the battery voltage tends to vary with the state of charge. By measuring the open-circuit voltage (OCV) of the battery pack 110a, 110b, 110c, 110d and comparing it to a voltage-SOC curve, the SOC can be estimated.

[0114] Coulomb counting: This method, also known as Ampere-hour (Ah) counting, involves measuring the current flowing into or out of the battery pack 110a, 110b, 110c, 110d over time. By integrating the current over time, the total charge delivered or consumed can be calculated, providing an estimate of the SOC.

[0115] Impedance spectroscopy: This method involves applying an AC voltage or current signal to the battery pack 110a, 110b, 110c, 110d and measuring the resulting impedance response across a range of frequencies. SOC can be estimated by analyzing the battery pack's electrochemical impedance spectroscopy (EIS) data, which reveals information about the internal processes and characteristics of the battery pack 110a, 110b, 110c, 110d.

[0116] Model-based estimation: This method employs mathematical models, such as equivalent circuit models or electrochemical models, to describe the behavior of the battery pack 110a, 110b, 110c, 110d. By using measured voltage, current, and temperature data, along with model parameters, state estimation techniques like Kalman filtering or extended Kalman filtering (EKF) can be used to estimate the SOC.

[0117] Machine learning and data-driven methods: Advanced techniques such as artificial neural networks (ANN) and support vector machines (SVM) can be trained based on historical battery data to estimate the SOC.

[0118] Combining at least some of these methods, such as using voltage-based estimation together with coulomb counting or employing model-based estimation with data-driven techniques, can provide more accurate and reliable SOC estimates.

[0119] Step 502, which can be performed in some embodiments where step 501 has been performed, includes adjusting a lower threshold level and / or an upper threshold level of a battery temperature of the battery pack 110a, 110b, 110c, 110d based on the estimated 501 SOC.

[0120] The lower threshold level and / or the upper threshold level of the battery temperature can be adjusted 502 based on power requirements of the vehicle 100 and / or available power in the first set 105 of battery packs 110a, 110b, 110c, 110d.

[0121] Thus, the high power requirements of the vehicle 100 can require an upper threshold level of battery temperature to be elevated.

[0122] Step 503 comprises detecting a battery temperature below a lower threshold level for all of the battery packs 110a, 110b, 110c, 110d.

[0123] The battery temperature can be determined based on one or several temperature sensors 240a, 240b, 240c, 240d communicatively connected to the controller 210.

[0124] Step 504 comprises allowing the heating arrangement 230 to provide heat to a first set 105 of battery packs 110a, 110b, 110c, 110d among the plurality of battery packs 110a, 110b, 110c, 110d when detecting 503 a battery temperature below a lower threshold level, while not allowing the heating arrangement 230 to provide heat to a second set 107 of battery packs 110a, 110b, 110c, 110d among the plurality of battery packs 110a, 110b, 110c, 110d, wherein the first set 105 of battery packs 110a, 110b, 110c, 110d is different from the second set 107 of battery packs 110a, 110b, 110c, 110d.

[0125] The battery packs 110a, 110b, 110c, 110d included in the first set 105 of battery packs 110a, 110b, 110c, 110d and / or the second set 105 of battery packs 110a, 110b, 110c, 110d can be selected based on historical data of previous selections for equalizing the life time of the battery packs 110a, 110b, 110c, 110d.

[0126] An advantage resulting herefrom is that the life time of the on-board battery packs 110a, 110b, 110c, 110d is equalized.

[0127] The first set 105 of battery packs 110a, 110b, 110c, 110d can comprise one single battery pack 110a, 110b, 110c, 110d or several battery packs 110a, 110b, 110c, 110d, such as two, three, four, etc.

[0128] In some embodiments, the first set 105 of battery packs 110a, 110b, 110c, 110d and the second set 105 of battery packs 110a, 110b, 110c, 110d can together constitute all of the battery packs 110a, 110b, 110c, 110d of the vehicle 100.

[0129] Step 505, which can be performed in some alternative embodiments, includes monitoring the battery temperature of the battery packs 110a, 110b, 110c, 1 lOd included in the first set 105 of battery packs 110a, 110b, 110c, 1 lOd.

[0130] Temperature monitoring can be performed based on repeated temperature measurements by the temperature sensors 240a, 240b, 240c, 240d, which can be repeatedly transmitted to the communicatively connected controller 210.

[0131] Step 506, which can be performed in some embodiments in which step 501 has been performed, includes disallowing the heating device 230 to provide heat to the first set 105 of battery packs 110a, 110b, 110c, 1 lOd when the monitored 505 battery temperature of the battery packs 110a, 110b, 110c, 1 lOd in the first set 105 of battery packs 110a, 110b, 110c, 1 lOd exceeds an upper threshold level, and allowing the heating device 230 to provide heat to the second set 107 of battery packs 110a, 110b, 110c, 1 lOd.

[0132] The controller 210 can include or be referred to as a computer, which includes any hardware or hardware / firmware devices implemented using processing circuitry, such as but not limited to a processor, a central processing unit (CPU), a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a system on chip (SoC), a programmable logic unit, a microprocessor, an application specific integrated circuit, or any other device capable of electronically performing operations in a defined manner.

[0133] The controller 210 can also include a receiving circuit configured for receiving signals from various communicatively connected entities on the vehicle 100, such as the temperature sensors 240a, 240b, 240c, 240d, the battery heaters 231, 231a, 231b, 231c, 231d, the fluid regulators 233a, 233b, 233c, 233d, the respective switches 250a, 250b, 250c, 250d for each battery pack 110a, 110b, 110c, 1 lOd, in different embodiments.

[0134] Furthermore, in some embodiments, the controller 210 can comprise a memory. The optional memory can comprise a physical device for temporarily or permanently storing data and / or programs, i.e. sequences of instructions. According to some embodiments, the memory can comprise an integrated circuit comprising silicon-based transistors. In different embodiments, the memory can comprise, for example, a memory card, a flash memory, a USB memory, a hard disk, or another similar volatile or non-volatile storage unit for storing data, such as, for example, a ROM (Read-Only Memory), a PROM (Programmable Read-Only Memory), an EPROM (Erasable PROM), an EEPROM (Electrically Erasable PROM), etc.

[0135] Furthermore, the controller 210 can comprise a signal transmitter. The signal transmitter can be configured for transmitting control signals to be received by a communicatively connected entity.

[0136] The previously described method steps 501-506 of the method 500 to be performed by the controller 210 can be implemented by one or more processors within the controller 210 and a computer program product for performing at least some of the functions of the method steps 501-506. Thus, a computer program product comprising instructions for performing the method steps 501-506 in the controller 210 can perform the method 500 comprising at least some of the method steps 501-506 for adjusting the temperature of the battery pack 110a, 110b, 110c, 110d in the electric vehicle 100 via the heating device 230 when the computer program is loaded into the one or more processors of the controller 210.

[0137] The above-mentioned computer program product can be provided, for example, in the form of a computer-readable medium. In some embodiments, the computer-readable medium can be a non-transitory computer-readable medium, for example a tangible electronic, magnetic, optical, infrared, electromagnetic, and / or semiconductor system, apparatus, and / or device.

[0138] The computer-readable medium can carry a computer program comprising program code for performing at least some of the method steps 501-506 according to some embodiments when loaded into the controller 210.

[0139] In some embodiments, the computer-readable medium can comprise program code for performing the above-described method steps 503-504.

[0140] In some embodiments, the computer-readable medium can comprise program code for performing the above-described method steps 503-506.

[0141] In some embodiments, the computer readable medium can comprise program code for performing the method steps 501-504 described above.

[0142] In some embodiments, the computer readable medium can comprise program code for performing the method steps 501-506 described above.

[0143] The terminology used in the description of the embodiments as illustrated in the accompanying drawings is not intended to limit the described method 500; controller 210; computer program; and / or electric vehicle 100. Various changes, substitutions and / or alterations can be made without departing from embodiments of the application as defined by the appended claims.

[0144] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. As used herein, the term “or” is to be interpreted as the mathematical OR, i.e. as the inclusive disjunction, unless otherwise explicitly stated. Additionally, the singular forms “a”, “an” and “the” are to be interpreted as “at least one”, thus possibly including plural entities, unless explicitly stated otherwise. It will be further understood that the terms “includes”, “including”, “comprises” and / or “comprising”, specify the presence of stated features, integers, steps, operations, components, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, components, and / or groups thereof. A single unit such as a processor can fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. A computer program can be stored / distributed on a suitable medium, such as an optical storage medium or a solid-state storage medium supplied together with or as part of other hardware, but can also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.

Claims

1. A method (500) performed by a controller (210) of an electric vehicle (100), wherein the vehicle (100) comprises a plurality of battery packs (110a, 110b, 110c, 110d), which are each associated with a heating device (230) configured to individually adjust a temperature of each respective battery pack (110a, 110b, 110c, 110d), wherein the method (500) comprises the steps of: detecting (503) a battery temperature below a lower threshold level in all of the battery packs (110a, 110b, 110c, 110d); and when detecting (503) that the battery temperature is below the lower threshold level, allowing (504) the heating device (230) to provide heat to a first set (105) of battery packs (110a, 110b, 110c, 110d) of the plurality of battery packs (110a, 110b, 110c, 110d) while not allowing the heating device (230) to provide heat to a second set (107) of battery packs (110a, 110b, 110c, 110d) of the plurality of battery packs (110a, 110b, 110c, 110d), wherein the first set (105) of battery packs (110a, 110b, 110c, 110d) is different from the second set (107) of battery packs (110a, 110b, 110c, 110d). monitoring (505) a battery temperature of the battery packs (110a, 110b, 110c, 110d) included in the first set (105) of battery packs (110a, 110b, 110c, 110d); and when the monitored (505) battery temperature of the battery packs (110a, 110b, 110c, 110d) in the first set (105) of battery packs (110a, 110b, 110c, 110d) exceeds an upper threshold level, not allowing (506) the heating device (230) to provide heat to the first set (105) of battery packs (110a, 110b, 110c, 110d) and allowing the heating device (230) to provide heat to the second set (107) of battery packs (110a, 110b, 110c, 110d).

2. The method (500) of claim 1, further comprising the step of:

3. The method (500) according to any one of the preceding claims, comprising the steps of: estimating (501) a state of charge of each respective battery pack (110a, 110b, 110c, 110d); and adjusting (502) the lower and / or upper threshold level of the battery temperature based on the estimated (501) state of charge. ​ ​ 4. The method (500) according to claim 3, wherein the lower threshold level and / or the upper threshold level of the battery temperature is adjusted (502) based on power requirements of the vehicle (100) and / or available power in the first set (105) of battery packs (110a, 110b, 110c, 110d).

5. The method (500) according to any one of the preceding claims, wherein battery packs (110a, 110b, 110c, 110d) included in the first set (105) of battery packs (110a, 110b, 110c, 110d) and / or the second set (105) of battery packs (110a, 110b, 110c, 110d) are selected for equally distributing the selection over time based on historical data of previous made selections.

6. The method (500) according to any one of the preceding claims, wherein the first set (105) of battery packs (110a, 110b, 110c, 110d) and the second set (105) of battery packs (110a, 110b, 110c, 110d) constitute all battery packs (110a, 110b, 110c, 110d) of the vehicle (100).

7. A controller (210) of an electric vehicle (100), wherein the vehicle (100) comprises a plurality of battery packs (110a, 110b, 110c, 110d), each associated with a heating device (230) configured to individually adjust a temperature of each respective battery pack (110a, 110b, 110c, 110d), wherein the controller (210) is configured to: detect, via temperature sensors (240a, 240b, 240c, 240d), battery temperatures in all battery packs (110a, 110b, 110c, 110d) that are below a lower threshold level; when detecting that the battery temperatures are below the lower threshold level, allow the heating devices (230) to provide heat to a first set (105) of battery packs (110a, 110b, 110c, 110d) in the plurality of battery packs (110a, 110b, 110c, 110d), while not allowing the heating devices (230) to provide heat to a second set (107) of battery packs (110a, 110b, 110c, 110d) in the plurality of battery packs (110a, 110b, 110c, 110d), wherein the first set (105) of battery packs (110a, 110b, 110c, 110d) is different from the second set (107) of battery packs (110a, 110b, 110c, 110d).

8. The controller (210) according to claim 7, the controller being further configured to: monitoring, via the temperature sensors (240a, 240b, 240c, 240d), a battery temperature of the battery packs (110a, 110b, 110c, 110d) included in the first set (105) of battery packs (110a, 110b, 110c, 110d); and disallowing the heating device (230) to provide heat to the first set (105) of battery packs (110a, 110b, 110c, 110d) when the monitored battery temperature of the battery packs (110a, 110b, 110c, 110d) in the first set (105) of battery packs (110a, 110b, 110c, 110d) exceeds an upper threshold level, and allowing the heating device (230) to provide heat to the second set (107) of battery packs (110a, 110b, 110c, 110d).

9. The controller (210) according to any one of claims 7 to 8, the controller being further configured to: estimate a state of charge of each respective battery pack (110a, 110b, 110c, 110d); and adjust the lower and / or upper threshold level of the battery temperature based on the estimated state of charge.

10. The controller (210) according to claim 9, wherein the lower and / or upper threshold level of the battery temperature is adjusted based on a power requirement of the vehicle (100) and / or available power in the first set (105) of battery packs (110a, 110b, 110c, 110d).

11. The controller (210) according to any one of claims 7 to 10, the controller being configured to select battery packs (110a, 110b, 110c, 110d) included in the first set (105) of battery packs (110a, 110b, 110c, 110d) and / or the second set (105) of battery packs (110a, 110b, 110c, 110d) for equally distributing the selection in time based on historical data of previous made selections.

12. An electric vehicle (100), the electric vehicle comprising a plurality of battery packs (110a, 110b, 110c, 110d), each associated with a heating device (230), the heating device (230) being configured to individually adjust a temperature of each respective battery pack (110a, 110b, 110c, 110d); a controller (210) according to any one of claims 7 to 11; and temperature sensors (240a, 240b, 240c, 240d) communicatively connected to the controller (210).

13. The electric vehicle (100) according to claim 12, wherein the heating device (230) comprises: a battery heater (231) configured to heat a fluid; a battery heater (231) configured to heat a fluid; a plurality of heat exchangers (234a, 234b, 234c, 234d), each heat exchanger configured to raise a temperature of one respective battery pack (110a, 110b, 110c, 110d); a pipe (232) connected to the battery heater (231), the pipe configured to convey heated fluid from the battery heater (231) to the heat exchangers (234a, 234b, 234c, 234d); a plurality of fluid regulators (233a, 233b, 233c, 233d) each communicatively connected to the controller (210) and configured to allow or disallow heated fluid from the pipe (232) to reach a respective heat exchanger (234a, 234b, 234c, 234d).

14. The electric vehicle (100) of claim 12, wherein the heating arrangement (230) comprises: a plurality of battery heaters (231a, 231b, 231c, 231d) each communicatively connected to the controller (210) and configured to raise a temperature of one respective battery pack (110a, 110b, 110c, 110d).

15. A computer program comprising program code for performing the method (500) of any one of claims 1 to 6 when the computer program is executed in the controller (210) of any one of claims 7 to 11.

16. A computer readable medium comprising instructions which, when executed by the controller (210) of any one of claims 7 to 11, cause the controller (210) to carry out the steps of the method (500) of any one of claims 1 to 6.

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