Method for controlling a motor vehicle battery heating element

Abstract

Method for controlling (1, 1', 1'') a heating member of an electric storage battery of a motor vehicle, said heating member allowing said battery to reach a target temperature sufficient for all of the available energy of the battery to be usable by the motor vehicle, said heating member being powered by said battery, said method comprising the following steps: Determining (2) a parameter of evolution of the energy consumption of said motor vehicle; Acquiring (3) a value representative of the state of charge of said battery; Determining (4) a threshold temperature depending on the value representative of the state of charge of said battery acquired and the determined driving profile; Measuring (5) the temperature of said battery; Commanding (6) the activation of the heating member of said battery when the measured temperature is less than or equal to the determined threshold temperature.Abstract figure: Figure 1.

Description

Title of the invention: Method for controlling a motor vehicle battery heating element

[0001] The present invention relates to the management of electric accumulator batteries of a motor vehicle, more particularly to a method of controlling a battery heating member.

[0002] Electric storage batteries are used mainly in hybrid or electric motor vehicles. The performance of a battery, such as its power, available energy and durability, are very sensitive to its temperature. Indeed, at low temperatures, the battery undergoes a double degradation: internal losses will increase and the useful energy will be reduced due to the impossibility of completely discharging the battery. To allow it to operate in optimal conditions, it is therefore necessary to warm it up when it is too cold.

[0003] There are several ways of managing battery heating. The first way is to heat the battery during the charging phase prior to the driving phase at the driver's request. This method thus makes it possible to use the network energy to heat the battery without affecting its autonomy. However, it does not allow the battery's operating conditions to be optimized during travel.

[0004] Another means consists of heating the battery during the driving phase when its temperature falls below a certain predetermined threshold. The heating device then uses the battery to operate, thus reducing the autonomy of the vehicle. The use of a fixed threshold makes it possible to limit the degradation of the battery performance in most cases, however in certain cases the autonomy of the remaining battery is insufficient to allow the battery to reach a sufficiently high operating temperature to have optimal operating conditions.

[0005] Application EP3758131A1 presents a method for heating a motor vehicle battery as a function of a threshold comprising two parameters: a temperature and a value of the state of charge of the battery. The threshold used is therefore also a fixed threshold. This criterion is therefore not always optimal since the heating can be triggered when the battery does not really need it and thus degrade its autonomy.

[0006] The solutions proposed by this prior art have limits in terms of vehicle consumption and optimization of the battery heating process.

[0007] Also, there is a need for a control method allowing heating to be activated only in relevant cases taking into account the current state of charge of the battery and the consumption of the vehicle.

[0008] A method is proposed for controlling a heating member of an electric accumulator battery of a motor vehicle, said heating member allowing said battery to reach a target temperature sufficient for all of the available energy of the battery to be usable by the motor vehicle, said heating member being powered by said battery, said method comprising the following steps: • Determine a parameter for the evolution of the energy consumption of said motor vehicle; • Acquire a value representative of the state of charge of said battery; • Determine a threshold temperature based on the value representative of the state of charge and the determined energy consumption evolution parameter, below which part of the available energy of said battery cannot be used by said motor vehicle; • Measure the temperature of said battery; • Command the activation of the heating element of said battery when the measured temperature is less than or equal to the determined threshold temperature.

[0009] Advantageously and in a non-limiting manner, the step of determining a parameter of evolution of the energy consumption of said motor vehicle comprises the use of a driving profile of the motor vehicle.

[0010] An advantage is being able to quickly determine energy consumption from a determined typical driving profile.

[0011] Advantageously and in a non-limiting manner, the step of determining a parameter of evolution of the energy consumption of said motor vehicle comprises the calculation of a forecast electrical consumption of said battery either by taking an average over the journey taken or by anticipating the consumption from a planned journey.

[0012] An advantage is being able to determine a precise electrical consumption which is close to the electrical consumption which will be achieved during the journey.

[0013] Advantageously and in a non-limiting manner, the step of determining the threshold temperature comprises a direct calculation or an interpolation on a threshold temperature map.

[0014] In particular, the values ​​are dependent on the intrinsic characteristics of the battery which for a given temperature and SOC indicates the available usable energy.

[0015] One advantage is that the calculation can be carried out quickly.

[0016] Advantageously and in a non-limiting manner, the method also comprises the following steps: • Determination of an extinction temperature based on the measured temperature above which the battery life is degraded; • Battery temperature measurement; and • Order the battery heating device to stop.

[0017] One advantage is being able to stop heating before degrading battery life.

[0018] Advantageously and in a non-limiting manner, the steps of the method are repeated according to a predetermined frequency.

[0019] The invention also relates to a device for controlling a heating member of an electric accumulator battery of a motor vehicle, said heating member allowing said battery to reach a target temperature sufficient for all of the available energy of the battery to be usable by the motor vehicle, said heating member being powered by said battery, said control device comprising: • Means for determining a driving profile of said motor vehicle; • Means for acquiring a value representative of the state of charge of said battery; • Means for determining a threshold temperature as a function of the value representative of the state of charge and the determined driving profile, below which part of the available energy of said battery cannot be used by said motor vehicle; • Means for measuring the temperature of said battery;

[0020] The invention relates to a control device comprising means for controlling the activation of the heating member of said battery when the measured temperature is less than or equal to the determined threshold temperature.

[0021] The invention also relates to a control device comprising means for controlling the switching off of the heating member of said battery when the measured temperature is greater than or equal to the determined temperature, with a view to switching off.

[0022] The invention also relates to an electrical system comprising a battery of electrical accumulators, a heating member and a control device.

[0023] The invention also relates to an electric or hybrid motor vehicle comprising an electrical system.

[0024] The invention also relates to any land, sea or air vehicle comprising an electric accumulator battery intended to store propulsion energy and an electrical system.

[0025] Other features and advantages of the invention will emerge from reading the description given below of several particular embodiments of the invention, given for informational purposes but not as a limitation, with reference to the appended drawings in which:

[0026] [Fig. 1] is a flowchart showing the different steps of the method for controlling a heating member of an electric accumulator battery of a motor vehicle according to a first embodiment.

[0027] [Fig.2] is a flowchart showing the different steps of the control method according to a second embodiment.

[0028] [Fig.3] is a flowchart showing the different steps of the control method according to a third embodiment.

[0029] The invention relates to an electrical system in a motor vehicle comprising an electric accumulator battery, a heating member and a device for controlling this heating member.

[0030] The heating member makes it possible to increase the temperature of the battery so that it reaches a predetermined target temperature corresponding to the temperature necessary for all of the available energy to be usable by the vehicle.

[0031] This control device implements a method 1 for controlling a heating member.

[0032] In this embodiment, the control device is an on-board computer, but it can alternatively be a processor, a processor core, or any other suitable device.

[0033] An advantage of the invention is to activate the heating of the battery only in cases where exploitation of a low state of charge and energy recovery have been identified.

[0034] According to a main embodiment of the invention, with reference to [Fig.l], the method 1 for controlling a heating member firstly comprises a step 2 of determining a parameter of the evolution of the energy consumption of the motor vehicle.

[0035] Thus the objective is to predict the speed of consumption of the available energy produced by the battery.

[0036] Here, this parameter of evolution of the energy consumption of the motor vehicle includes a driving profile of the vehicle.

[0037] The method 1 according to the invention comprises a step 3 of acquiring the value representative of the state of charge of the battery, in English State Of Charge, frequently abbreviated SoC.

[0038] The objective is to be able to adapt the temperature threshold according to the state of charge of the battery. Indeed, heating the battery is valuable if the energy recoverable by heating it is greater than the energy required for this heating.

[0039] Battery recovery means the ability to exploit all of the available energy produced by the battery.

[0040] Thus, the lower the state of charge, the more the heating of the battery will be valuable.

[0041] In the implementation of the invention, the acquisition step 3 can be carried out before the determination step 2.

[0042] The method 1 then comprises a step 4 of determining a threshold temperature TseuU as a function of the value representative of the state of charge of said acquired battery and of the determined driving profile.

[0043] Below this threshold temperature Tseuii, all of the available energy of said battery cannot be used by said motor vehicle.

[0044] Indeed, the objective of heating the battery is for it to reach a sufficient temperature so that the vehicle can exploit all of the available energy.

[0045] However, the battery is also used to electrically power the heating element.

[0046] It is therefore necessary to ensure that the battery has the energy necessary to power the heating element until it reaches the target temperature.

[0047] Thus, the threshold temperature Tseun corresponds to the temperature necessary for there to be sufficient usable energy available to power the vehicle and the heating device until the battery reaches the target temperature.

[0048] According to a particular embodiment, this step of determining the threshold temperature is carried out by direct calculation.

[0049] According to another particular embodiment, this determination step is carried out by interpolation on a precalculated temperature map.

[0050] The method according to the invention comprises a step 5 of measuring the temperature Tbat of the battery.

[0051] This measurement step is carried out by at least one temperature probe placed in the vicinity of the battery or on or in one of the constituent elements of the battery.

[0052] The method then comprises a command 6 for activating the heating member of said battery when the measured temperature Tbat is less than or equal to the determined threshold temperature TseuU.

[0053] According to a second embodiment, with reference to [Fig.2], method 1' is a modification of method 1 according to the main embodiment, for which the parameter of evolution of the energy consumption of the vehicle determined in the determination step 2 is a forecast of the electrical consumption of the vehicle.

[0054] This forecast is obtained here by averaging the electricity consumption over the journeys made.

[0055] In an alternative embodiment of this second embodiment, the consumption is estimated in advance from a journey planned by the vehicle's GPS, a mobile application connected to the vehicle, or any other means of guiding the motor vehicle.

[0056] According to a third embodiment, with reference to [Fig.3], the control method 1” comprises additional steps to those of the first and second embodiments, making it possible to determine a criterion for stopping the heating member and to control this stopping.

[0057] This third embodiment can thus indifferently complement method 1 of the first embodiment or method 1' of the second embodiment.

[0058] Indeed, since the heating element is powered by the battery, the battery's autonomy decreases during heating. Thus, it is necessary to be able to anticipate the stopping of heating, in order to limit the deterioration of the battery's autonomy.

[0059] For this, the method according to the invention firstly comprises a step 7 of determining an extinction temperature Textinction.

[0060] This extinction temperature corresponds to the target temperature to be reached during reheating minus a judiciously adjusted safety margin.

[0061] Indeed, when the battery heating member is stopped, the heating of the battery continues by thermal inertia. There is therefore a latency time between the heating member stopping and the battery temperature stopping increasing.

[0062] It is recommended that the threshold Textinction which determines the condition for switching off the battery heating be corrected in real time according to a judicious frequency to be defined, to prevent a variation in the consumption of the vehicle which may not be controlled (change in driving conditions: traffic, mass, weather, driving mode, slope, etc.) which could lead to the difference between the remaining usable energy and the energy required for heating tending towards zero or even becoming negative in the worst case. It is therefore provided, without limitation of solution, an algorithm which is based on the determination of an average consumption over a judiciously defined period from a monitoring of the evolution of the SOC, whether this average consumption is observed or predicted. Which algorithm leads thus to the real-time determination of the Textinction value, optimal and adapted to the current and future circumstances of rolling, of extinction condition 7.

[0063] Once this threshold temperature has been determined, the method comprises a new step 8 of measuring the current temperature T' of the battery.

[0064] Finally, the method comprises a step 9 of controlling the stopping of the heating member when the measured battery temperature T' is greater than or equal to the calculated extinction temperature Textinction.

[0065] Steps 6, 7, 8 and control step 9 are repeated until control step 9 activates the stopping of the heating member.

[0066] According to a particular implementation, the steps of the method are repeated according to a predetermined frequency.

[0067] Thus, the battery can be heated when necessary, particularly on long journeys.

[0068] According to a particular embodiment, the various data measured and calculated during the implementation of a control method according to the invention are made available to the user of the vehicle, for example by displaying this data on a human-machine interface, such as a display or a screen on the dashboard of the motor vehicle.

[0069] According to an alternative embodiment, which can be indifferently based on each of the preceding embodiments, the method 1-1” comprises a step of verifying the data before the step of determining the threshold temperature Tseuii.

[0070] Thus, if a piece of data turns out to be erroneous, then the method does not take these values ​​into account and does not trigger reheating even if the battery temperature Tbat is lower than the calculated threshold temperature Tseuii.

Claims

Claims

1. Method for controlling (1, 1', 1”) a heating member of an electric storage battery of a motor vehicle, said heating member allowing said battery to reach a target temperature sufficient for all of the available energy of the battery to be usable by the motor vehicle, said heating member being powered by said battery, said method comprising the following steps: • Determining (2) a parameter of evolution of the energy consumption of said motor vehicle; • Acquiring (3) a value representative of the state of charge of said battery; • Determining (4) a threshold temperature as a function of the value representative of the state of charge and the determined parameter of evolution of the energy consumption, below which a portion of the available energy of said battery is unusable by said motor vehicle;• Measure (5) the temperature of said battery; • Command (6) the activation of the heating member of said battery when the measured temperature is less than or equal to the determined threshold temperature; • Determine (7) a switch-off temperature as a function of the measured temperature above which the battery life is degraded; • Measure (8) the temperature of the battery; and • Command (9) the stopping of the battery heating device, the steps of said method being repeated according to a predetermined frequency.;

2. Control method (1) according to claim 1, characterized in that the step of determining (2) a parameter of evolution of the energy consumption of said motor vehicle comprises the use of a driving profile of said motor vehicle.

3. Control method (1') according to claim 1 or 2, characterized in that the step of determining (2) a parameter of evolution of the energy consumption of said motor vehicle includes the calculation of a forecast electrical consumption of said battery either by taking an average over the journey taken or by anticipating the consumption from a planned journey.

4. Control method (1, 1', 1”) according to any one of claims 1 to 3, characterized in that the step of determining (4) the threshold temperature comprises a direct calculation or an interpolation on a threshold temperature map.

5. Device for controlling a heating member of an electric accumulator battery of a motor vehicle configured to implement the method according to any one of claims 1 to 4, said heating member allowing said battery to reach a target temperature sufficient for all of the available energy of the battery to be usable by the motor vehicle, said heating member being powered by said battery, said control device comprising: • Means for determining a driving profile of said motor vehicle; • Means for acquiring a value representative of the state of charge of said battery;• Means for determining a threshold temperature as a function of the value representative of the state of charge and the determined driving profile, below which a portion of the available energy of said battery cannot be used by said motor vehicle; • Means for measuring the temperature of said battery; • Means for controlling the activation of the heating member of said battery when the measured temperature is less than or equal to the determined threshold temperature • Means for controlling the switching off of the heating member of said battery when the measured temperature is greater than or equal to the determined temperature, with a view to switching off.;

6. 10 Electrical system comprising an electric storage battery, a heating member and a control device according to claim 5.

7. An electric or hybrid motor vehicle comprising an electrical system according to claim 6.

8. Land, sea or air vehicle comprising an electric accumulator battery intended to store propulsion energy and an electrical system according to claim 6.

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