Method for temporarily extending the autonomy of an electric vehicle

Abstract

The present invention relates to a method for temporarily extending the autonomy of an electric vehicle, which includes a traction battery having a nominal available energy capacity less than its maximum actual energy capacity. The method includes a step of releasing additional available capacity in order to temporarily increase the vehicle's autonomy.

Description

Technical field

[0001] The present invention relates to a method for temporarily extending the autonomy of an electric vehicle. Background art

[0002] In the context of the current global warming consensus, reducing carbon dioxide (CO2) emissions is a major challenge for motor vehicle manufacturers, and the standards are becoming increasingly demanding in this regard.

[0003] In addition to continuously improving the efficiency of traditional thermal engines (which is accompanied by a reduction in CO2 emissions), electric vehicles ("EV" for short) and hybrid thermal-electric vehicles ("HEV" for short) are now considered the most promising solutions for reducing CO2 emissions. In recent years, a variety of different electric energy management technologies have been tested to meet the requirements of EVs and HEVs. For example, lithium-ion (Li-ion) batteries offer an excellent compromise between the energy density that favors autonomy and the power density that favors performance (especially in terms of acceleration). This is why lithium-ion batteries are usually selected as the "traction battery" for powering the motors of EVs or HEVs.

[0004] One obstacle to the development of EVs remains their autonomy, which is still limited compared to that of thermal-powered vehicles. This is the problem that the present invention aims to solve.

[0005] The prior art teaches different strategies for permanently enhancing the autonomy of EVs, in particular in order to increase the capacity of the battery and the efficiency of the motor.

[0006] Other strategies aim to temporarily enhance the autonomy of EVs in some exceptional usage cases through a so-called "range-extender". This range-extender can be, for example, a thermal range-extender operating as a fossil fuel-based power generator on the Nissan Note e-Power. This range-extender can also be a fuel cell type range-extender operating with liquid hydrogen as used in the document DE 202017003371 U. This range-extender can also be a metal-air battery type range-extender as in the document FR 3027259 A1. A major drawback of these solutions is their complexity and their implementation cost, and they require the range-extender to be refilled regularly, whether with gasoline, hydrogen or even aluminum plates, which requires at least a trip to a certain station or even maintenance operations. This is the drawback that the present invention aims to avoid. Summary of the invention

[0007] The aim of the present invention is in particular to remedy the above-mentioned drawbacks. To this end, the subject of the present invention is a method for temporarily extending the autonomy of an electric vehicle, which electric vehicle comprises a traction battery, the nominal available energy capacity of which is less than its maximum actual energy capacity. The method comprises a step of releasing an additional available capacity in order to temporarily increase the autonomy of the vehicle.

[0008] Advantageously, the capacity release step may comprise: calculating the current maximum actual capacity; and selecting, via a human-machine interface, in particular a smartphone or a tablet computer, a value of the release capacity to be added to the nominal available capacity within the limits of the calculated maximum actual capacity. Thus, the user benefits from great flexibility in reserve use, which allows the user to adjust his or her capacity extension according to his or her actual needs and budget. In addition, this ability to optimally regulate the capacity extension tends to maintain the maximum capacity of the battery over time and thus the durability of the battery.

[0009] Also advantageously, the capacity release step may comprise the step of selecting a release criterion via a human-machine interface, in particular a smartphone or a tablet computer, at the expiration of which the available capacity reverts to the nominal available capacity. For example, the release criterion may comprise a time criterion. Thus, the user benefits from the reliability of use, which guarantees that the user's use of the capacity extension will never exceed his or her actual needs and budget. This function limits the risk of unnecessarily prolonging the capacity extension time, and this also tends to maintain the maximum capacity of the battery over time and thus the durability of the battery.

[0010] Also advantageously, if the vehicle is traveling towards a previously known final destination, at the expiration of the release criterion, the available capacity may revert to the nominal available capacity only when the vehicle actually reaches the final destination.

[0011] In one embodiment, the step of selecting the release capacity value may comprise transmitting, via a display or via an auditory device, an additional autonomy value corresponding to the selected capacity value.

[0012] The step of selecting the release capacity value and / or the release criterion may comprise transmitting, via a display or via an auditory device, an amount to be paid corresponding to the selected value.

[0013] Furthermore, the subject of the present invention is a system comprising hardware means and software means implementing all the steps of such a method.

[0014] Finally, the subject of the present invention is a vehicle comprising such a system.

[0015] In addition to not requiring any filling or maintenance operations, the main advantage of the previously described invention lies in its ease of implementation, since it can be implemented in any current electric vehicle, including battery computers and vehicle computers. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Other features and advantages of the present invention will become apparent from the following description given with reference to the accompanying drawings, which represent the same exemplary embodiments of the invention:

[0017] Figure 1 Shows a schematic diagram of an exemplary architecture in which the method according to the present invention can be implemented in an electric vehicle;

[0018] Figure 2 Shows an example of power limitation performed by a block for handling the limitation of the power required for the inverter;

[0019] Figure 3 Shows an example of a "set / reset" switch;

[0020] Figure 4 Shows an example of a human-machine interface on a smart phone or tablet computer;

[0021] Figure 5 Shows an example of a human-machine interface on a smart phone or tablet computer; and

[0022] Figure 6 Shows an example of a human-machine interface on a smart phone or tablet computer when energy is being released.

[0023] In these figures, the same reference numerals denote the same elements. DETAILED DESCRIPTION

[0024] Today, the new generation of EV traction batteries offer greater capacity at a more acceptable price compared to the past. For motor vehicle manufacturers, it has become possible to offer a range of EVs with diverse nominal capacities. For its part, the applicant envisions presenting two different versions for the same EV model, including the same battery with an actual capacity (i.e., physical capacity) of 52 kWh: one version with a nominal capacity (i.e., sold to customers) of 30 kWh, and another version with a nominal capacity of 52 kWh. The following describes an innovative method for managing the energy and power of an EV, which provides an innovative service for temporarily extending the nominal capacity to the driver based on the fact that the actual capacity of the battery is greater than its nominal capacity.

[0025] ​​​​​​The general principle of the method is that when the actual capacity of the battery is greater than the nominal capacity of the EV and it is desired and physically possible for the driver, to offer him or her the option to purchase additional capacity that will be available for a determined period of time and / or under determined conditions.

[0026] In an advantageous embodiment, the driver can choose from several options, for example via the vehicle's dashboard or via his or her smartphone.

[0027] For example, the driver can choose within limits the amount of additional energy he or she wishes to release, this amount being within certain limits that depend on the actual situation and will be communicated to him or her, his or her smartphone, or the dashboard at any time by the vehicle computer.

[0028] He or she can also choose the energy release time. For example, he or she can choose a single use until the end of the current journey, and in this case the capacity will return to the nominal capacity at the next charge. This option is useful in cases where the user notices that he or she does not have enough autonomy to reach the destination. Thus, the existence of such a service eliminates the driver's fear of being immobilized by a breakdown. He or she can also choose a determined time, such as 24 hours, a weekend, or a week. In this case, he or she will be able to, for example, retain the extended capacity until the charge after the selected time has elapsed. The fact that the return to the nominal capacity will only be authorized after charging ensures that even if the release time chosen by the driver has expired, he or she will not encounter the unpleasant surprise of a reduced autonomy during the journey.

[0029] To this end, the method described below manages the following for the case where the nominal capacity of the client is less than or equal to the actual capacity of the battery and this nominal capacity can vary over time according to the user's choice: traction, state of charge (or "SOC" for short of "state of charge"), autonomy, and charge stop.

[0030] Figure 1 A schematic diagram shows an exemplary architecture in which the method according to the invention can be implemented in an electric vehicle. The schematic diagram particularly shows a part of the vehicle architecture: a vehicle controller 1 that communicates with a traction battery 2 including its own computer, a charger 3, a dashboard 4, and an inverter 5. The inverter 5 makes it possible to generate torque using an electric motor (not shown in Figure 1 ).

[0031] The controller 1 executes various processes, in particular block 1 for processing the energy and SOC of the battery 2, block 2 for processing the limits of the power required for the inverter 5, block 3 for managing the end of the charge of the battery 2, and block 4 for managing the interaction with the smartphone or tablet computer 6.

[0032] ​The block 1 for processing energy and SOC receives as input the signal Batt_En sent by the computer of the traction battery 2, which signal represents the physical level of the energy of the battery 2 at the current moment (in kilowatt-hours (kWh)). The block 1 also receives as input the signal En_a_liberer sent by the block 4, which signal represents the amount of additional energy to be released (in kWh).

[0033] The block 1 generates the signal TdB_SOC as an output to the instrument panel 4 for display to the driver, which signal represents the processed SOC level. It is a value between 0% and 100%. It can also be used by the remaining embedded software strategies. It only corresponds to the SOC level known to the driver.

[0034] The block 1 also generates the signal TdB_En as an output to the instrument panel 4 for display to the driver, which signal represents the processed battery energy level (in kWh). It will also be used by the remaining embedded software strategies, especially the software strategy for estimating the remaining autonomy displayed to the driver.

[0035] These signals are obtained according to the following equations:

[0036] [Mathematical formula 1]

[0037]

[0038] where useful_capacity (available capacity) is a parameter corresponding to the nominal capacity (less than the physical capacity of the battery), and:

[0039] [Mathematical formula 2]

[0040] TdB_En = max(0; E_AvailDisch_New_No_Sat)

[0041] where,

[0042] [Mathematical formula 3]

[0043] E_AvailDisch_New_No_Sat = Batt_En - En_reelle_0%_SOC_New

[0044] The signal En_reelle_0%_SOC_New represents the physical quantity of the energy that the battery has when TdB_SOC is 0%. It is calculated according to the following equation:

[0045] [Mathematical formula 4]

[0046]

[0047] The signal En_a_liberer is generated by block 4 in the manner described in the paragraph below that explains the operation of block 4.

[0048] When TdB_SOC and TdB_En are low, block 2 limits the power and thus the motor torque. This limitation is managed such that the power decreases gradually as TdB_SOC decreases, so as not to surprise the driver. This block 2 generates the signal Batt_P_max_disch_New as an output, which will limit the maximum power and thus the maximum torque Tq_Max that the motor can generate through the inverter 5. This signal Batt_P_max_disch_New is obtained according to the following equation:

[0049] [Mathematical formula 5]

[0050] Batt_P_max_disch_New

[0051] = min{Batt_P_max_disch; max[P_Bat_Disch_Min;

[0052] (P_Bat_Disch_Avail_En0 + E_AvailDisch_New_No_Sat·dP_Bat_Disch_dEn)]}

[0053] The final torque request Final_Mot_Tq_req of the inverter 5 is calculated in module 7 as the minimum between the torque request from the driver Driver_Tq_req and the maximum generable torque Tq_Max that gives the power limit "Batt_P_Max_disch_New".

[0054] Block 2 receives the signal Batt_P_max_disch as an input from the battery 2, which represents the maximum discharge power (in kilowatts (kW)) that the traction battery 2 can physically provide. The parameters for setting the strategy are:

[0055] P_Bat_Disch_Avail_En0, which represents the discharge power (in kW) still available when the processed battery energy is 0 kWh;

[0056] dP_Bat_Disch_dEn, which represents the slope of the decrease in the available battery discharge power as a function of the battery energy level (in kW per kWh (kW / kWh));

[0057] P_Bat_Disch_Min, which represents the remaining discharge power under the power limit (in kW / kWh).

[0058] Figure 2 shows an example of power limitation by block 2. Note that the power "Batt_P_Max_disch_New" gradually decreases as "TdB_SOC" approaches 0. In Figure 2 , it will be noted that when "TdB_SOC" reaches the value 0, the power "Batt_P_Max_disch_New" is greater than 0, which allows the driver to travel a few more meters. If the driver continues to drive, then shortly after TdB_SOC = 0, "Batt_P_Max_disch_New" will also reach the value 0 ("dry" fault).

[0059] Block 3 manages the charging stop of battery 2 by generating a Boolean signal Flag_arret_ch for charger 3, which takes the value 1 when charging must stop and 0 otherwise. This signal is constructed according to the following logic:

[0060] [Equation 6]

[0061]

[0062] where Batt_arret_ch is a Boolean value sent by battery 2, which takes the value 1 when battery 2 requests to stop charging.

[0063] Block 4 manages the interaction between vehicle computer 1 and a smartphone or tablet computer 6 belonging to the driver. This block 4 receives the following signals sent by the smartphone or tablet computer 6 as inputs:

[0064] En_suppl_req, which is sent by the smartphone or tablet computer 6 and represents the amount of energy (in kWh) that the user wants to release;

[0065] Duree_liber_En, which is sent by the smartphone or tablet computer 6 and represents the time (in minutes) that the driver wants to release additional energy.

[0066] If the maximum authorized release time is X minutes, the range of possible values of this signal must be [0, X]. Then the value 0 is given the following meaning: The driver requests to release additional capacity until the next charge, i.e., to complete the current trip. In this case, this capacity will be restored to the nominal capacity at the next charge (i.e., immediately after the driver arrives at the charging point).

[0067] ​The driver can also directly request the release duration Duree_liber_En of the additional energy quantity En_suppl_req via his or her telephone or tablet computer 6, or via the vehicle's dashboard. Block 4 generates the following signals as outputs to the smartphone or tablet computer 6 in order to inform the driver by means of a display on said smartphone or tablet computer 6:

[0068] A Boolean value Flag_Lib_En_en_cours, which takes the value 1 when additional energy is being released relative to the nominal value and 0 otherwise;

[0069] Duree_rest_En_supp, which indicates to the driver in real time how much longer he or she will benefit from the extended capacity;

[0070] En_max_liberable, which indicates to the driver in real time the maximum amount of additional energy that he or she can release. This amount is associated with the physical capacity of the system and is transmitted by the computer 1 to the smartphone or tablet computer 6 at each instant. In a variant embodiment, one possibility is to allow the driver to select the amount of energy to be released via a gauge, the maximum value of which corresponds to the signal En_max_liberable.

[0071] As shown by Figure 3 , the signal Flag_Lib_En_en_cours can be obtained as the output of a "set / reset" (S / R) switch. The input S of the switch corresponds to the Boolean signal Debut_Lib_En. When the value of this Boolean signal is 1, the release of additional energy begins. The input R of the switch corresponds to the Boolean signal Fin_Lib_En. The fact that this Boolean signal reaches the value 1 marks the end of the release of additional energy.

[0072] The Boolean signal Debut_Lib_En is obtained according to the following equation:

[0073] [Mathematical formula 7]

[0074] Debut_Lib_En

[0075] =(En_suppl_req > 0) AND (NOT Flag_Lib_En_en_cours) AND (NOT Flag_charge)

[0076] Among them, Flag_charge (flag_charge) is a boolean value, which takes the value 1 when the vehicle is charging and 0 otherwise. Therefore, if the vehicle is not charging and no energy release has occurred, when the driver requests a positive additional energy En_suppl_req through his or her smartphone or tablet computer 6, or even through the dashboard 4, the release of energy begins.

[0077] The boolean signal Fin_Lib_En is obtained according to the following equation:

[0078] [Mathematical formula 8]

[0079]

[0080] Where:

[0081] [Mathematical formula 9]

[0082]

[0083] [Mathematical formula 10]

[0084] Duree_En_suppl = T_absol - T_debut

[0085] Where T_absol is a continuous counter inside the embedded computer, which gives the absolute time (calculated from the first wake-up in the service life of the computer)

[0086] And where:

[0087] [Mathematical formula 11]

[0088]

[0089] The signal En_a_liberer sent to block 1 is obtained as follows:

[0090] [Mathematical formula 12]

[0091]

[0092] Where:

[0093] [Mathematical formula 13]

[0094]

[0095] The output signal Duree_rest_En_supp sent to the smartphone or tablet computer 6 is obtained as follows:

[0096] [Mathematical formula 14]

[0097] Remaining Supplementary Duration = User Duration - Supplementary Duration

[0098] This embodiment has several consequences. The first consequence is that if the driver selects the option “complete the current journey” (i.e., Available Release Energy = 0), the capacity of the battery will return to its nominal capacity immediately after he or she has connected the vehicle to the charger (after he or she has reached the charging point). This option is useful in the case where the driver notices that he or she does not have enough autonomy to reach the destination. The availability of such a service also makes it possible to soothe the driver's fear of a breakdown preventing movement. Thus, Figure 4 and Figure 5 shows an example of a human-machine interface on the smartphone or tablet computer 6, which allows the driver to adjust the energy release parameters using two cursors, which make it possible to select the Required Supplementary Energy within the limits of the Maximum Liberable Energy and the Available Release Energy. In this example, in the case of an additional capacity of 1 kWh purchased for 12 euros (9 kWh available in total), the driver is informed that he or she has gained 5 kilometers (km) of autonomy, which is only available until the next charge.

[0099] Another consequence is that if the driver selects a certain period of time (e.g., two days or one week), he or she will retain the extended capacity until the charge after the selected time has elapsed. The fact that the return to the nominal capacity is only authorized after charging ensures that even if the release time selected by the driver has expired, he or she will not encounter the unpleasant surprise of a loss of autonomy while driving. Thus, Figure 6 shows an example of a human-machine interface on the smartphone or tablet computer 6 when the energy release is in progress, which particularly displays the Remaining Supplementary Duration with a value of 1 day 13 hours 7 minutes.

[0100] The output signal Maximum Liberable Energy sent to the smartphone or tablet computer 6 is obtained according to the following equation:

[0101] [Mathematical formula 15]

[0102]

[0103] Where, En_pas_liberable is a positive or zero setting parameter, which represents the amount of energy that is not allowed to be released from Battery 2 compared to its actual physical capacity. Where, En_reelle_0%_SOC_New is a signal representing the physical quantity of the energy available in Battery 2 when the processed SOC (TdB_SOC) is 0%. It is obtained as described above.

Claims

1. A method for temporarily extending the autonomy of an electric vehicle, the electric vehicle including a traction battery having a nominal available energy capacity less than its maximum actual energy capacity, the method being characterized in that, It includes steps to release additional available capacity to temporarily enhance the autonomy of the vehicle, where the steps to release additional available capacity include: - calculating the current maximum actual capacity; - displaying to the driver via a human-machine interface the maximum amount of additional energy he or she can release, within the limit of the calculated maximum actual capacity; - receiving via the human-machine interface the driver's adjustment of the energy release parameters; - receiving via the human-machine interface the amount of energy the driver has selected to release and adding this amount to the nominal available capacity.

2. The method according to claim 1, characterized in that, The steps to release additional available capacity include steps to select a release criterion via the human-machine interface, and when the release criterion expires, the available capacity reverts to the nominal available capacity.

3. The method according to claim 2, wherein The release criterion includes a time criterion.

4. The method according to claim 2, wherein If the vehicle is traveling towards a pre-known final destination, when the release criterion expires, the available capacity reverts to the nominal available capacity only when the vehicle actually reaches the final destination.

5. The method according to claim 1, wherein The step of the driver selecting the amount of energy to release includes transmitting, via a display or an auditory device, an additional autonomy value corresponding to the amount of energy to be released.

6. The method according to claim 2, wherein The step of the driver selecting the amount of energy to release and / or the release criterion includes transmitting, via a display or an auditory device, an amount to be paid corresponding to the selected value.

7. The method according to one of claims 1 and 2, characterized in that, The human-machine interface includes a smart phone or a tablet computer (6).

8. A system comprising hardware means and software means for implementing all the steps of the method according to any one of the preceding claims.

9. A vehicle comprising the system according to claim 8.

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