Method for determining a target temperature for thermal preconditioning of a battery in an automotive vehicle

Abstract

The invention relates to a method for determining a target thermal preconditioning temperature for a battery (40) of a motor vehicle (2) using a thermal management unit (30), prior to charging the battery using a charging station. The target preconditioning temperature is determined based on (i) information relating to the charging operation (charging time, state of charge of the battery at the start of the charging operation, charging power of the charging station used during the charging operation), and (ii) a non-zero positive net energy gain defined as the value obtained by subtracting an adjustment energy (energy required by the thermal management unit to reach the target temperature) from a charging energy gain (energy recovered by the battery at the target temperature compared to the energy recovered at an initial temperature).Figure to be published with the abbreviation: Fig.1.

Description

Title of the invention: Method for determining a target temperature for the thermal preconditioning of a battery in an automobile

[0001] The present invention relates to a method for determining a target temperature for the thermal preconditioning of a motor vehicle battery using a thermal management unit. The invention also relates to a method and a system for the thermal preconditioning of a motor vehicle battery using the determination method according to the invention.

[0002] The charging performance of a vehicle battery varies significantly with temperature and the battery's state of charge. Generally, for a given state of charge, a battery's charging performance increases with temperature. These variations lead to longer charging times and perceived irregularities in charging service for the customer. Consequently, some manufacturers are installing battery thermal management systems in their vehicles to improve charging performance in both cold and hot conditions, at the cost of higher energy consumption while driving.

[0003] In addition, there are charging stations with different power outputs, for example with a power output of 50kW or 130kW. Other power outputs are also available depending on the charging station manufacturer.

[0004] However, as already mentioned, the power acceptable to a battery during its charging varies according to its temperature and state of charge.

[0005] Thus, by way of example, [Fig. 3] is a graph representing the charging capacities of a 60 kWh battery for different states of charge and different battery temperatures. This figure shows that, in the case of a 50 kW charging station, it is not useful to heat the battery, which has an initial state of charge of 30%, to a temperature above 10 °C because the power of the station would not allow for an increase in the charging power. On the other hand, in the case of a 130 kW charging station, it is advantageous to heat it to a temperature above 10 °C. Depending on the initial state of charge of the battery, it is not necessarily useful to heat the battery as much as possible. For example, in [Fig. 3], for an initial state of charge between 10 and 20%, it can be seen that it is not useful to heat the battery to a temperature above 35 °C.

[0006] Some battery preconditioning strategies use as a target temperature a temperature that allows for maximum battery charging power. However, as shown in [Fig. 3], this leads to overconsumption of the unit thermal management when the charging station has too low a power output compared to this maximum power.

[0007] Furthermore, during charging operations, the charging time is often shorter than the charging time required to fully recharge the battery. However, the battery temperature for optimal charging will vary depending on the charging time. Strategies that optimize battery temperature to achieve a full charge can also lead to increased power consumption by the thermal management unit when the battery is not fully charged.

[0008] Thus, for example, document JP2020013726A describes a thermal management strategy that defines a target battery temperature at the start of charging. This target temperature is defined by guaranteeing the customer a net power gain during charging; that is, the power expended to bring the battery to the target temperature is less than the power gain resulting from the battery's temperature change. Depending on the battery characteristics and the thermal management system, several target temperatures can meet these criteria, but the net gain in charged energy, and therefore in range, for the customer will vary. According to the strategy described in this document, a charging start temperature is determined that minimizes the charging time up to a maximum battery charge level (full charge).This solution does not maximize net customer profit because charging at fast charging stations very rarely achieves a maximum charge rate.

[0009] There is therefore a need to avoid overconsumption of a thermal management unit during the preconditioning of a battery before a charging operation, in particular before a fast charging operation.

[0010] The invention aims to provide a method for determining a target conditioning temperature which optimizes the energy recovered by the battery during a charging operation and maximizes the net energy gain for a given charging time, particularly for a short charging time which does not allow a complete recharge of the battery.

[0011] To this end, a first object of the invention relates to a method for determining a target temperature for the thermal preconditioning of a motor vehicle battery by means of a thermal management unit, this thermal preconditioning being prior to charging said battery using a charging station. This method can typically be implemented by a computer. This target preconditioning temperature corresponds to a battery temperature at the beginning of the charging operation, allowing for optimization the energy recovered by the battery during this charging operation and the net energy gain for a given charging time.

[0012] The determination method according to the invention comprises: - the receipt of information relating to a battery charging operation, including a planned charging operation, said information including the charging time of the charging operation, the state of charge of the battery at the start of the charging operation, and the charging power of the charging station used during the charging operation, - the determination of the target preconditioning temperature based on (i) information received relating to said battery charging operation and (ii) a non-zero positive net energy gain, this net energy gain being defined as the value obtained by subtracting an adjustment energy from a charging energy gain, said adjustment energy being defined as the energy required by the thermal management unit for the battery to reach the target temperature, and said charging energy gain being defined as the energy gain recovered by the battery operated at the target temperature compared to the energy recovered when the battery temperature is not at the target temperature.

[0013] Such a target temperature thus optimizes the energy recovered by the battery during the charging operation and for a given net energy gain. This charging time can be set to a relatively short duration, for example, 15 to 30 minutes, which does not allow for a complete battery recharge. In other words, the charging operation time can typically be determined so that the final state of charge of the battery is less than 100%, for example, 60 to 90%.

[0014] The battery charge at the target temperature can thus be optimized for this short charging time. Consequently, the duration of a journey requiring one or more battery charging operations can be significantly reduced.

[0015] Moreover, using a net energy gain as a target temperature selection parameter ensures a gain during loading compared to methods based on a net power gain.

[0016] Advantageously, the determined target temperature can correspond to a temperature at which the net energy gain is maximized. The amount of energy recovered during charging is then maximized for the charging time considered, which makes it possible to further reduce the duration of a journey.

[0017] Advantageously, the charging energy gain can be an energy gain relative to energy recovered by the battery when the battery temperature is not at the target temperature and is at a predefined initial temperature. This predefined initial temperature can be an estimated battery temperature at The arrival at the charging station during the charging operation or the maximum battery charging temperature. Preferably, this predefined initial temperature can be an estimated temperature upon arrival at the charging station: the net energy gain is then determined more accurately.

[0018] The determination method according to the invention can use a pre-established database for at least one charging time and for a plurality of charging station power ratings usable for a charging operation. Such a database, for each charging time coupled with a charging station power rating and a battery state of charge, associates a battery temperature with a net energy gain. It is then easy to determine a target temperature that corresponds to the battery temperature for which the net energy gain is positive and non-zero, and preferably maximal.

[0019] In one embodiment, the data table can be established based on external climatic conditions and / or an initial battery temperature. It can then contain different data sets for different types of climatic conditions, for example, for different external temperatures and / or different initial battery temperatures. The determination of the target preconditioning temperature can then be performed based on an external temperature and / or the initial battery temperature, typically an actual temperature.

[0020] The determination method according to the invention can be implemented in a configured determination unit, in particular one programmed for this purpose. Typically, this determination unit may comprise a computer, or more generally at least one processor or any other type of digital computing device. The determination unit may also comprise a plurality of distinct processors or digital computing devices, forming different means of the unit, cooperating with each other. The processor(s) may include storage means, which may be random access memory (RAM), electrically erasable programmable read-only memory (EEPROM), flash memory, external memory, or the like. These storage means may, among other things, store received data, a control model, and one or more computer programs.

[0021] The invention also relates to a method for thermally preconditioning a motor vehicle battery prior to charging said battery using a charging station, comprising: - a step of determining a target preconditioning temperature implementing the process according to the invention, - a step of adjusting the temperature to the target temperature using a battery thermal management unit.

[0022] During the temperature adjustment step, the battery thermal management unit can thus be controlled to heat / cool the battery to the target preconditioning temperature.

[0023] Advantageously, the adjustment step may include: - determining the preconditioning time required for the thermal management unit for the battery to reach the target temperature, based in particular on the initial battery temperature, the outside temperature, and optionally on information predicting the variation in battery temperature under vehicle driving conditions, - receiving information regarding the time remaining before the charging operation, - comparing the preconditioning time to the time remaining before the charging operation, and - When the preconditioning time is less than or equal to the remaining time, adjust the battery temperature to the target temperature using the thermal management unit. - when the preconditioning time is greater than the remaining time, estimate a battery temperature at the end of the remaining time and a net energy gain or a charge energy gain at said estimated temperature and adjust the battery temperature when the net energy gain or the charge energy gain is greater than a threshold; otherwise do not adjust the battery temperature.

[0024] Advantageously, the determination and adjustment steps can be repeated at given time intervals, for example every 100ms, in order to adapt the target preconditioning temperature and the thermal preconditioning of the battery in real time.

[0025] The invention also relates to a thermal preconditioning system for a battery of a motor vehicle equipped with a thermal management unit, said system comprising: - a unit for determining a target preconditioning temperature for the battery prior to charging said battery using a charging station, - a unit for adjusting the battery temperature to said target temperature previously determined by means of said thermal management unit.

[0026] According to the invention: - the determination unit is configured to implement the step of determining a target preconditioning temperature of the thermal preconditioning method of the invention, - the adjustment unit is configured to implement the adjustment step of the thermal preconditioning method of the invention.

[0027] The determination unit can, in particular, be configured to implement the method for determining a target preconditioning temperature according to the invention. The determination unit can be as previously described.

[0028] The adjustment unit may here include a computer, or more generally at least one processor or any other type of digital computer. The adjustment unit may also include a plurality of distinct processors or digital computers, forming different means of the unit, cooperating with each other. The processor(s) may include storage means, which may be random access memory (RAM), electrically erasable programmable read-only memory (EEPROM), flash memory, external memory, or other. These storage means may, among other things, store received data, a control model, and one or more computer programs. The adjustment unit may, in particular, be configured to control the thermal management unit and communicate with the determination unit and the thermal management unit.To this end, each unit may include means of communication with other units, for example input / output ports or interfaces or any existing wired or wireless means of communication.

[0029] Advantageously, the adjustment unit can be configured to: - determine a preconditioning time required by the thermal management unit for the battery to reach the target temperature, notably based on an initial battery temperature, the ambient temperature, and optionally, information predicting the variation in battery temperature under vehicle driving conditions, - receive information regarding the time remaining before the charging operation, - compare the preconditioning time to the time remaining before the charging operation, and - when the preconditioning time is less than or equal to the remaining time, adjust the battery temperature to the target temperature using the thermal management unit, and - when the preconditioning time is greater than the remaining time, estimate a battery temperature at the end of the remaining time and estimate a net energy gain or a charge energy gain at said estimated temperature and adjust the battery temperature when the net energy gain or the charge energy gain is greater than a threshold; otherwise do not adjust the battery temperature.

[0030] When the preconditioning time is less than the remaining time, the adjustment unit can also be configured to determine a conditioning start time such that the target temperature is reached by the battery when the remaining time has elapsed.

[0031] The invention also relates to a navigation system for an electric or hybrid motor vehicle, said vehicle comprising at least one electric motor powered by at least one battery and a battery thermal management unit, said navigation system comprising: - a navigation unit configured to determine a travel route for said vehicle based on an initial state of charge of the vehicle, and - a thermal preconditioning system according to the invention.

[0032] In particular, the navigation unit can further be configured to: - plan at least one charging operation along the route when the initial battery charge level is insufficient to complete the predetermined route, and - transmit to the thermal preconditioning unit, and in particular to its determination unit, the information relating to each planned battery charging operation, said information including a charging time of the charging operation, a state of charge of the battery at the start of the charging operation, a charging power of the charging station used during the charging operation.

[0033] According to another object, the invention relates to an electric or hybrid vehicle comprising at least one electric motor powered by at least one battery and a battery thermal management unit, characterized in that it includes a navigation system according to the invention.

[0034] Other features and advantages of the invention will become apparent from the following description of particular embodiments of the invention, given by way of example but not limitation, with reference to the accompanying drawings in which:

[0035] [Fig. 1] is a schematic representation of a navigation system forming part of of a vehicle according to an embodiment of the invention.

[0036] [Fig.2] is a schematic representation of the steps implemented by the different units of a navigation system according to an embodiment of the invention.

[0037] [Fig.3] is a graph representing the charging power of a battery as a function of the battery's state of charge (SOC) and temperature.

[0038] Identical references may be used from one figure to another to designate identical or similar elements.

[0039] Figure 1 schematically represents a navigation system 1 comprising a navigation unit 10 and a preconditioning system 20. The preconditioning system 20 includes a unit 210 for determining a target preconditioning temperature and a unit 220 for adjusting the temperature of a battery. The navigation system 1 controls a thermal management unit 30 for a battery 40. This navigation system 1 is integrated into a vehicle 2, typically an electric or hybrid vehicle comprising at least one electric motor 50 powered by the battery 40.

[0040] The thermal management unit 30 of the battery typically comprises a battery heating system, for example using Joule heating, and a battery cooling system, using, for example, a cooling fluid (air, water, or other). This thermal management unit 30 may be a heating, ventilation, and air conditioning unit, also referred to by the acronym HVAC.

[0041] Each of the navigation 10, determination 210 and adjustment 220 units may include one or more processors or other digital computers, one or more memories and one or more ports or interfaces for communication between them and / or with a display terminal 12 and / or with the thermal management unit 30.

[0042] The navigation unit 10 of the navigation system 1, also called the "Route Planner" or "Electric Route Planner," is a unit configured (programmed) to determine a vehicle's travel route based on the vehicle's initial state of charge (SOCinit) of its battery. Such a unit may include one or more processors or other digital computers, one or more memories, and means for communicating with the adjustment unit and the determination unit. This navigation unit 10 may further include a multimedia component (also called IVI for InVehicle Infotainment) for accessing navigation services. This navigation unit 10 is typically connected to a display terminal 12 (for example, a screen) for displaying multimedia data, including navigation data (maps, etc.).

[0043] In general, the navigation unit 10 is configured to determine a travel route by taking into account external information such as weather conditions, road congestion, etc. It may also take into account information from previous trips relating to the driver's driving style, or other factors. Based on the initial state of charge, the navigation unit 10 determines whether one or more charging operations are necessary during the route and searches for locations where this charging operation can be carried out. Generally, these locations are chosen to minimize travel time. The navigation unit may also have access to the type of charging station available for each charging operation.

[0044] The navigation unit 10 can thus be configured to implement the steps STEP1 to STEP4, as schematically represented [Fig.2].

[0045] During a first step STEP1, the navigation unit 10 determines a route for the movement of said vehicle according to an initial state of charge of the vehicle.

[0046] Then, in a second step STEP2, the navigation unit 10 determines whether the initial state of charge is sufficient to complete the entire route without stopping. During this step, the navigation unit 10 can, for example, determine the amount of energy necessary for completing the route, notably by taking into account, as usual, information relating to weather conditions, road congestion, the driver's driving style, etc., and then comparing this amount of energy required to the initial state of charge. If the navigation unit 10 determines that the state of charge is insufficient (Y), it then proceeds to step STEP3; otherwise (N), the process proceeds to step STEP14 and stops.

[0047] During step STEP3, the navigation unit 10 plans at least one charging operation to be carried out along the route. Typically, the charging operation(s) are planned to minimize the total duration of the route. This planning includes an estimation of the battery's state of charge prior to each charging operation and the determination of a charging time.

[0048] Then, during step STEP4, the navigation unit 10 transmits to the determination unit 210 information relating to each planned charging operation, this information including the charging time of the planned charging operation, the state of charge of the battery at the start of the planned charging operation, and the charging power of the charging station used during the planned charging operation.

[0049] This information relating to charging operations can be received or determined by the navigation unit 10. Typically, the charging power of the charging station used during the charging operation is information received, while the charging time of the charging operation and the state of charge of the battery at the beginning of the charging operation are information determined, in particular estimated.

[0050] This charging time is typically less than the charging time required to fully charge a battery. It can typically be less than 1 hour, for example, on the order of 15 to 30 minutes. In general, a navigation unit 10 aims to minimize travel time, and consequently to reduce charging time.

[0051] Step STEP5 is then implemented by the determination unit 210. During this step, this unit determines the target preconditioning temperature as a function of (i) information received relating to said planned charging operation and (ii) a non-zero positive net energy gain.

[0052] This net energy gain GE_net is defined as the value obtained by subtracting an adjustment energy E_ajust from a charging energy gain GE_charg:

[0053] [Maths 1]

[0054] GE_net = GE_charge - E_ajust (Eq. 1)

[0055] The adjustment energy E_ajust is defined as the energy required by the thermal management unit 30 for the battery 40 to reach the target temperature. This energy therefore varies depending on the thermal management unit 30 and the battery 40. It also varies depending on the initial temperature of the battery, which can be measured or estimated.

[0056] The charging energy gain GE_charg is defined as the energy recovered by the battery when operated at the target temperature compared to the energy recovered when the battery temperature is not at the target temperature. This GE_charg gain can thus be expressed according to equation 2 as a function of the energy recovered by the battery when operated at the target temperature E_Tcible and the energy recovered when the battery temperature is not at the target temperature, E_Tinit:

[0057] [Maths 2]

[0058] GE_charge = E_Tcible - E_Tinit (Eq. 2)

[0059] The energy recovered when the battery temperature is not at the target temperature E_Tinit is energy recovered when the battery temperature is at an initial temperature, which may be a predefined temperature taken as a reference. This predefined initial temperature may be an estimated temperature of the battery upon arrival at the charging station for the planned charging operation or a maximum battery charging temperature.

[0060] The initial temperature will preferably be an estimated temperature of the battery upon arrival at the charging station for the planned charging operation. This temperature may have been previously estimated by the navigation unit 10, for example during step STEP3, typically based on climatic conditions, driving conditions, etc., and then transmitted to the determination unit 210 during step STEP4.

[0061] Preferably, the target temperature determined during this STEP5 step corresponds to a temperature for which the net energy gain GE_net is maximal.

[0062] Typically, the STEP5 step uses a database previously established for at least one charging time and for a plurality of charging station powers usable for a charging operation, and in which this database, for each charging time coupled with a charging station power and a battery state of charge, associates a battery temperature with a net energy gain GE_net.

[0063] The initial temperature used to determine E_Tinit may depend on climatic conditions: it will then be possible to establish different data sets according to different climatic conditions, for example for cold or hot climatic conditions.

[0064] Tables 1 and 2 present examples of information contained in this database, previously determined for a 60kWh battery, taking -10°C as the initial temperature used to determine the energy recovered when the The battery temperature is not at the target temperature (E_Tinit). This initial temperature corresponds to cold climatic conditions.

[0065] Table 1 shows the net energy gain GE_net determined for different battery start-up charging temperatures for an initial state of charge SOCini of the battery of 15%, a charging time of 30 minutes and in the case of a charging station with a charging power Pcharge= 50kW and a charging station with a charging power Pcharge =130 kW.

[0066] Table 1 shows that for a charging station with a power of 50kW, the temperature which maximizes the net energy gain, and which corresponds to the target preconditioning temperature which we seek to determine, is 15 °C, whereas for the charging station with a power of 130 kW, this temperature is 35 °C.

[0067] Table 2 shows the net energy gain GE_net determined for different battery charging start temperatures for an initial battery state of charge SOCini of 40%, a charging time of 30 minutes, and in the case of a charging station with a charging power Pcharge = 50 kW and a charging station with a charging power Pcharge = 130 kW. The temperatures that maximize the net energy gain, and which correspond to the target preconditioning temperatures that we seek to determine, are 35°C for the 50 kW charging station and 20°C for the 130 kW charging station.

[0068] [Tables 1] SOCini = 15% Start of charge temperature -10°C (REF) 5°C 15°C 20°C 35°C Pcharge = 50kW 20.5 kWh 21.45 kWh 22.47 kWh 20.62 kWh 16.26 kWh Pcharge = 130kW 20.5 kWh 24.45 kWh 26.27 kWh 30.62 kWh 34.26 kWh

[0069] [Tables 2] SOC ini = 40% Start of charge temperature -10°C (REF) 5°C 15°C 20°C 35°C Pcharge = 50kW 17kWh 16.45 kWh 15.77 kWh 17.62 kWh 19.26 kWh Pcharge = 130kW 17kWh 16.45 kWh 15.77 kWh 24.62 kWh 22.26 kWh

[0070] The database can be pre-established from measurements taken during vehicle road tests and / or from estimates, for a particular thermal management unit and for a particular battery. When the database includes datasets established according to climatic conditions, the determining unit 210 can then receive outside temperature information from a sensor or the navigation unit 10, and subsequently determine the target temperature from the dataset corresponding to the outside temperature information.

[0071] The database can also contain several datasets established according to the initial battery temperature, which allows for a more precise determination of the adjustment energy and consequently of the net energy gain. In this case, the determination unit 210 can then receive information on the actual initial battery temperature, for example from a sensor or estimated, for example by the navigation unit, and then determine the target temperature from the dataset corresponding to the actual initial temperature information.

[0072] Preferably, the database may include datasets established according to climatic conditions and the initial temperature of the battery.

[0073] At the end of step STEP5, the determination unit 210 thus determined a target preconditioning temperature for the battery for the next planned charging operation.

[0074] The target temperature thus determined is then transmitted in step STEP 6 to the adjustment unit 220 configured to control the thermal management unit 30 of the battery. This control of the thermal management unit 30 can be implemented in step STEP 7 to adjust the battery temperature to the target temperature.

[0075] Since this target preconditioning temperature is an optimal battery temperature at the start of the next scheduled charging operation, it is preferable that the battery preconditioning (i.e., heating or cooling) from the actual battery temperature to the target temperature be implemented so that the battery reaches the target temperature upon arrival at the charging station. This avoids operating the thermal management unit 30 for longer than necessary.

[0076] For this purpose, the adjustment unit can be configured to optimize the control of the thermal management unit 30, for example by implementing the STEP8-STEP12 steps described below, typically between STEP6 and STEP7.

[0077] During a STEP8 step, the adjustment unit 220 determines a preconditioning time Tp required by the thermal management unit 30 for the battery 40 reaches the target temperature which was previously determined by the determination unit 210.

[0078] For this purpose, the adjustment unit 220 can receive information including the initial battery temperature, the actual measured or estimated battery temperature, the outside temperature, and optionally, information predicting the variation in battery temperature under vehicle driving conditions. The preconditioning time can then be determined based on this information. In particular, the information predicting the variation in battery temperature under vehicle driving conditions allows for consideration of battery warm-up during the vehicle's journey to the charging station, resulting in a more accurate estimation of the preconditioning time. This information can be received from the navigation unit 10.

[0079] This determination of the preconditioning time can be carried out using a pre-established database for a given thermal management unit, associating a preconditioning time with a temperature difference between the target temperature and the initial battery temperature, the initial battery temperature possibly being corrected by the temperature variation prediction information. The preconditioning time can also be estimated from a thermal model of the thermal management unit.

[0080] Before or after step STEP8, the adjustment unit 220 receives, during a step STEP9, information relating to a remaining time Tr before the charging operation. This information is typically received from the navigation unit 10.

[0081] Then, during a STEP10 step, the adjustment unit 220 compares the preconditioning time to the time remaining before the planned charging operation.

[0082] When the preconditioning time Tp is less than or equal to the remaining time Tr (Y), the adjustment unit proceeds to step STEP7 and commands the thermal management unit 30 to adjust the battery temperature to the target temperature. Otherwise (N), the adjustment unit 220 proceeds to step STEP14 and stops the process (not shown [Fig. 2]) or may proceed to a step STEP11 in which it estimates (i) a battery temperature at the end of the remaining time and (ii) a net energy gain or a charge energy gain at said estimated temperature. During a step STEP12, the adjustment unit then compares the estimated net energy gain or charge energy gain to a threshold value and proceeds to step STEP7 to adjust the battery temperature when the net energy gain or charge energy gain is greater than this threshold (Y); otherwise (N), the process proceeds to step STEP14 and stops.

[0083] Optionally, when the preconditioning time Tp is less than or equal to the remaining time Tr(Y), the adjustment unit can proceed from step STEP10 to step STEP10' before proceeding to step STEP7. During this optional step STEP 10 determines a preconditioning start time such that the target temperature is reached by the battery when the remaining time has elapsed. It then proceeds to STEP 7 to adjust the battery temperature, with the thermal management unit being activated at this preconditioning start time.

[0084] It may be advantageous to repeat the steps STEP1 to STEP7, including the optional steps STEP8-STEP12, at regular time intervals for real-time control of battery preconditioning and better energy management.

[0085] It should be noted that choosing the target temperature based on the net energy gain is more optimal than if a net power gain is used.

[0086] For example, if we consider that it takes a power of 5kW for one hour to precondition a battery to a given temperature (i.e. an energy consumed of 5kWh), which allows a power gain of 10 kW for a charge of 15 minutes compared to a non-preconditioned battery (i.e. an energy gain of 2.5 kWh).

[0087] So, the net energy gain is -2.5 kWh (2.5 kWh -5 kWh), which is not favorable for the customer and means that the temperature considered should not be taken as the target temperature, while the net power gain is 5kW (10 kW -5 kW), which may suggest that the temperature is suitable.

[0088] Optimizing the target temperature at the start of a planned charging operation using the determination method according to the invention thus makes it possible to minimize charging time, minimize the overconsumption of energy induced by the battery thermal management unit and thus reduce the overall time of a journey.

Claims

Demands

1. A method for determining a target thermal preconditioning temperature for a battery (40) of a motor vehicle by means of a thermal management unit, this thermal preconditioning being prior to a charging operation of said battery by means of a charging station, characterized in that it comprises: - the receipt of information relating to a battery charging operation, said information including a charging time of the charging operation, a state of charge of the battery at the beginning of the charging operation, a charging power of the charging station used during the charging operation, - the determination of the target preconditioning temperature as a function of (i) the information received relating to said battery charging operation and (ii) a non-zero positive net energy gain,This net energy gain is defined as the value obtained by subtracting an adjustment energy from a charging energy gain, said adjustment energy being defined as the energy required by the thermal management unit for the battery to reach the target temperature, and said charging energy gain being defined as the energy recovered by the battery operating at the target temperature compared to the energy recovered when the battery temperature is not at the target temperature.

2. A method of determination according to claim 1, characterized in that the determined target temperature corresponds to a temperature for which the net energy gain is maximal.

3. Method of determination according to claim 1 or 2, characterized in that the charging energy gain is an energy gain relative to energy recovered by the battery when the battery temperature is not at the target temperature and is at a predefined initial temperature, optionally chosen from an estimated temperature of the battery on arrival at the charging station of the charging operation and a maximum charging temperature of the battery.

4. A method of determination according to any one of claims 1 to 3, characterized in that the determination step uses a database previously established for at least one charging time and for a plurality of usable charging station power ratings for a charging operation, and in which said database, for each charging time coupled with a charging power of a charging station and a state of charge of the battery, associates a battery temperature with a net energy gain.

5. Method of thermal preconditioning a battery of a motor vehicle prior to an operation of charging said battery by means of a charging station, characterized in that it comprises: - a step of determining a target preconditioning temperature implementing the method according to any one of claims 1 to 4, - a step of adjusting the temperature to the target temperature by means of a battery thermal management unit.

6. A thermal preconditioning method according to claim 5, characterized in that said adjustment step comprises: - determining a preconditioning time required by the thermal management unit for the battery to reach the target temperature, - receiving information regarding the time remaining before the charging operation, - comparing the preconditioning time to the time remaining before the charging operation, and - when the preconditioning time is less than or equal to the remaining time, adjusting the battery temperature to the target temperature by means of the thermal management unit, - when the preconditioning time is greater than the remaining time,Estimate a battery temperature at the end of the remaining time and estimate a net energy gain or a charge energy gain at said estimated temperature, and adjust the battery temperature when the net energy gain or charge energy gain is greater than a threshold; otherwise, do not adjust the battery temperature.

7. Thermal preconditioning method according to claim 5 or 6, characterized in that the step of determining a target temperature and the adjustment step are repeated at given time intervals.

8. Thermal preconditioning system (20) for a battery of a motor vehicle equipped with a thermal management unit, said system comprising: - a unit for determining (210) a target temperature for preconditioning the battery prior to charging said battery using a charging terminal, - a unit for adjusting the battery temperature to said target temperature previously determined by means of said thermal management unit, characterized in that - the determining unit is configured to implement the step of determining a target temperature for preconditioning of the thermal preconditioning method of any one of claims 5 to 7, - the adjusting unit is configured to implement the step of adjusting the thermal preconditioning method of any one of claims 5 to 7.

9. Navigation system (1) of an electric or hybrid motor vehicle, said vehicle comprising at least one electric motor powered by at least one battery and a battery thermal management unit, said navigation system comprising: - a navigation unit (10) configured to determine a travel route for said vehicle based on an initial state of charge of the vehicle, characterized in that it further comprises a thermal preconditioning system (20) according to claim 8, - the navigation unit (10) being further configured to: - plan at least one charging operation along the route when the initial state of charge of the battery is insufficient to complete the previously determined route, and - transmit to the thermal preconditioning unit information relating to each planned battery charging operation,This information includes the charging time, the battery's state of charge at the start of the charging operation, and the charging power of the charging station used during the charging operation.

10. Electric or hybrid vehicle (1) comprising at least one electric motor (50) powered by at least one battery (40) and a battery thermal management unit (30), characterized in that it comprises a navigation system (1) according to claim 9.

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