METHOD FOR ESTIMATING THE PROGRESS STATE OF VOLTAGE BALANCING CARRIED OUT AT THE TERMINALS OF CELLS OF A BATTERY OF AN ELECTRIC OR HYBRID VEHICLE

Abstract

One aspect of the invention relates to a method 100 for estimating a progress state of a voltage balancing carried out at the terminals of cells of a battery of an electric or hybrid vehicle, the cells being arranged by an alternation of first and second cells, the vehicle comprising a plurality of slave microcontrollers, each slave microcontroller being capable of supervising a group of first and second cells, when the master microcontroller receives a wake-up request, the method 100 executes a step of determining 106 a progress state of the balancing carried out by at least one slave microcontroller, said progress state being a function of first and second balancing durations to be carried out recorded, of a shutdown duration of the master microcontroller depending on a switch-off time and a wake-up time of said master microcontroller. Figure to be published with the abstract: Figure 3.

Description

Title of the invention: METHOD FOR ESTIMATING THE PROGRESS OF A VOLTAGE BALANCING CARRIED OUT AT THE TERMINALS OF CELLS OF A BATTERY OF AN ELECTRIC OR HYBRID VEHICLE TECHNICAL FIELD OF THE INVENTION

[0001] The field of the invention is that of balancing the charge states of the cells of a battery. It relates more particularly to a method for estimating the progress of a voltage balancing carried out at the terminals of cells of a battery of an electric or hybrid vehicle. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0002] An electric, hybrid or even rechargeable hybrid vehicle comprises an electric storage battery formed of a large number of cells in series and / or in parallel. If in a storage battery, all the cells have characteristics close to each other, there are however dispersions or differences, in particular physical, such as a dispersion of capacity in Ampere-hours (Ah), and of resistance in ohms (Q). There are also dispersions, generally temporary, in the states of these cells, such as the difference in state of charge, generally called SOC (from the English State Of Charge), and / or temperature.

[0003] Over time and with the use of the battery, all these physical dispersions and differences in state cause the cells to age differently. This difference in the evolution of cell aging results in a state of health, known by the abbreviation SOH (from the English State Of Health), which differs from one cell to another. The differences in state of health between cells connected in series is a limiting parameter since the total usable capacity of the battery is directly impacted. Indeed, the greater the difference in charge between the cells, the more the total usable capacity of the battery decreases. This therefore has a negative impact on the autonomy of the vehicle equipped with such a battery.

[0004] In order to overcome this drawback, it is known to carry out a balancing of the charge states of the cells on a regular basis. This balancing is ensured by a battery management unit, known by the English term Battery Management System (BMS).

[0005] Balancing can be achieved by transferring electrical energy from one cell to another adjacent cell via the control of transistors, for example of the MOSFET type. To achieve such balancing, it is usually considered that a first cell (or odd cell) is arranged between two second cells (or even cells), and that a second cell is disposed between two first cells. Thus, the charging or discharging of a cell is controlled via the transfer of energy from a first cell to an adjacent second cell, or from a second cell to an adjacent first cell.

[0006] This type of balancing strategy is implemented in batteries whose cells are distributed in groups, each group of cells being controlled by a slave microcontroller. The slave microcontroller of each group determines the voltage across each cell in its group of cells, then transmits these voltage values ​​to a master microcontroller. Depending on these voltage values, the master microcontroller determines for each of the cells a necessary balancing time corresponding to a closing or opening time of the transistor associated with the cell.

[0007] The master microcontroller then transmits a balancing request to one or more slave microcontroller(s). This request includes a balancing duration for each first cell and a balancing duration for each second cell.

[0008] Each slave microcontroller having received a request then alternates, via the control of the transistors, the balancing, for example every five seconds, between the first cells and the second cells whose state of charge must be balanced. As illustrated in [Fig.l], if we consider, for a given slave microcontroller, a maximum balancing time of one hundred minutes for the first cells C1 and a maximum balancing time of twenty minutes for the second cells C2, the given slave microcontroller alternates every five seconds between the balancing of the first cells C1 and second cells C2 until reaching the balancing time of twenty minutes for the second cells C2, then continues the balancing of the first cells C1 until reaching one hundred minutes.

[0009] This balancing strategy is executed when the motor vehicle is asleep. "Asleep" means the state of a motor vehicle at a standstill and for which most of the computers are stopped. When the vehicle is asleep, the master microcontroller of the vehicle is woken up frequently, for example, every four hours, to ensure that the balancing process being executed by the slave microcontrollers is finalized. To do this, the master microcontroller interrogates the slave microcontrollers to determine the balancing duration performed. However, if the link between one of the slave microcontrollers and the master microcontroller is broken, the master microcontroller is unable to determine the balancing duration performed.

[0010] In addition, when the vehicle is restarted, some vehicles require a reset of all slave microcontrollers. Thus, when the master microcontroller requests the progress of the balancing process from the microcontrollers slave microcontrollers, the latter have no data to transmit to it. Thus, the master microcontroller is not able to determine whether the cell balancing process is complete. The slave microcontrollers must therefore determine the voltage across each cell, transmit these voltage values ​​to the master microcontroller, which will then determine a new balancing request for one or more slave microcontroller(s). This process is obviously long. Summary of the invention

[0011] An objective of the invention is to propose a solution for estimating a progress status of a voltage balancing carried out at the terminals of cells of a battery of a vehicle which is not impacted by a fault in the transmission of information from one of the slave microcontrollers to the master microcontroller.

[0012] To this end, the invention thus relates, in its broadest acceptance, to a method for estimating a state of progress of a voltage balancing carried out at the terminals of cells of a battery of an electric or hybrid vehicle, the cells being arranged by an alternation of first and second cells, the vehicle comprising a plurality of slave microcontrollers, each slave microcontroller being capable of supervising a group of first and second cells, the method comprising the steps executed, by a master microcontroller, of: • Receive a shutdown request from the master microcontroller; • Determine for each slave microcontroller, and • For each first cell supervised by said slave microcontroller, a first balancing duration of said first cell to be carried out, and • For each second cell supervised by said slave microcontroller, a second balancing duration of said second cell to be carried out; • Record a time of switching off of said master microcontroller and the first and second balancing durations to be carried out by each slave microcontroller in a non-volatile memory; • Turn off the master microcontroller; • When the master microcontroller receives a wake-up request, determine a progress status of the balancing performed by each slave microcontroller, the progress status being a function of the first and second balancing durations to be performed recorded, a master microcontroller shutdown duration depending on said shutdown time and a master microcontroller wake-up time.

[0013] Thanks to the method according to the invention, when it wakes up, the master microcontroller is not not dependent on the slave microcontrollers, or even on the communication link with them, to determine the progress of the balancing carried out during its sleep. Thus, if communication between one of the slave microcontrollers and the master microcontroller is broken or if the data of the slave microcontrollers is erased, the master microcontroller is able to determine whether the balancing process is finalized or not. If the balancing process is not finalized, the master microcontroller can determine the remaining balancing time and transmit an updated balancing request to the slave microcontrollers. For this, it is not necessary to request data from the slave microcontrollers.

[0014] In addition to the characteristics which have just been mentioned in the preceding paragraph, the method according to the invention may have one or more complementary characteristics among the following, considered individually or according to all technically possible combinations.

[0015] According to a non-limiting implementation of the invention, the step of determining a progress status of the executed balancing comprises the steps, for each slave microcontroller, of: • Select from the first cells a first maximum balancing duration and from the second cells a second maximum balancing duration; • Determine a maximum overall balancing time equal to the addition of the first maximum balancing time with the second maximum balancing time selected; • If the master microcontroller shutdown time is greater than the maximum overall balancing time, determine the completion of the balancing performed by the slave microcontroller.

[0016] According to a non-limiting implementation of the invention, the step of determining a progress status of the executed balancing comprises the steps, for each slave microcontroller, of: • Select from the first cells a first maximum balancing duration and from the second cells a second maximum balancing duration; • Determine a maximum overall balancing time equal to the addition of said first maximum balancing time with said second selected maximum balancing time; • If the master microcontroller shutdown time is less than the maximum overall balancing time, estimate for each first cell and each second cell, a balancing time carried out during the shutdown of the master microcontroller.

[0017] According to a non-limiting implementation of the invention, the step of estimating, for each first cell and each second cell, a balancing duration carried out during the shutdown of the master microcontroller comprises the steps of: • Determine a first balancing duration allocated to the first cells equal to the master microcontroller shutdown duration divided by two, the possible decimal of which is rounded up to the next higher integer, and a second balancing duration allocated to the second cells equal to the master microcontroller shutdown duration divided by two, the possible decimal of which is considered to be zero; • When the first balancing time allocated to the first cells is less than the first maximum balancing time and the second balancing time allocated to the second cells is less than the second maximum balancing time, • Determine a maximum balancing duration of the first cells performed equal to the first balancing duration allocated to the first cells; • Determine a maximum balancing duration of the second cells carried out equal to the second balancing duration allocated to the second cells; • Determine for each first cell, a balancing duration performed equal to the minimum value between the first balancing duration of the first cell to be performed and the maximum balancing duration of the first cells performed; • Determine for each second cell, a balancing duration performed equal to the minimum value between the second balancing duration of the second cell to be performed and the maximum balancing duration of the second cells performed.

[0018] According to a non-limiting implementation of the invention, the step of estimating for each first cell and each second cell, a balancing duration carried out during the shutdown of the master microcontroller comprises the steps of: • Determine a first balancing duration allocated to the first cells equal to the master microcontroller shutdown duration divided by two, the possible decimal of which is rounded up to the next higher integer, and a second balancing duration allocated to the second cells equal to the master microcontroller shutdown duration divided by two, the possible decimal of which is considered to be zero; • If the first balancing time allocated to the first cells is in- less than the first maximum balancing duration and the second balancing duration allocated to the second cells is greater than the second maximum balancing duration, • Determine a maximum balancing duration of the first cells carried out equal to the first balancing duration allocated to the first cells to which is added a second remainder of the second balancing duration allocated to the second cells not used, said second remainder being equal to the second balancing duration allocated to the second cells from which is subtracted the second maximum balancing duration; • Determine a maximum balancing time of the second cells performed equal to the second maximum balancing time; • Determine for each first cell, a balancing duration performed equal to the minimum value between the first balancing duration of the first cell to be performed and the maximum balancing duration of the first cells performed; • Determine for each second cell, a balancing duration performed equal to the minimum value between the second balancing duration of the second cell to be performed and the maximum balancing duration of the second cells performed.

[0019] According to a non-limiting implementation of the invention, the step of estimating, for each first cell and each second cell, a balancing duration carried out during the shutdown of the master microcontroller comprises the steps of: • Determine a first balancing duration allocated to the first cells equal to the master microcontroller shutdown duration divided by two, the possible decimal of which is rounded up to the next higher integer, and a second balancing duration allocated to the second cells equal to the master microcontroller shutdown duration divided by two, the possible decimal of which is considered to be zero; • If the first balancing time allocated to the first cells is greater than the first maximum balancing time and the second balancing time allocated to the second cells is less than the second maximum balancing time, • Determine a maximum balancing duration of the first cells carried out equal to the first maximum balancing duration; • Determine a maximum balancing duration of the second cells carried out equal to the second balancing duration allocated to the second cells to which a first remainder of the first balancing duration allocated to the first unused cells, said first remainder being equal to the first balancing duration allocated to the first cells from which the first maximum balancing duration is subtracted; • Determine for each first cell, a balancing duration performed equal to the minimum value between the first balancing duration of the first cell to be performed and the maximum balancing duration of the first cells performed; • Determine for each second cell, a balancing duration performed equal to the minimum value between the second balancing duration of the second cell to be performed and the maximum balancing duration of the second cells performed.

[0020] According to a non-limiting implementation of the invention, the method comprises, for each slave microcontroller, the steps of: • Estimate for each first cell and each second cell, a remaining balancing time, said remaining balancing time being a function of: • For each first cell, the balancing time carried out by said first cell during the shutdown of the master microcontroller and the first balancing time of said first cell to be carried out; • For each second cell, the balancing duration performed by said second cell during the shutdown of the master microcontroller and the second balancing duration of said second cell to be performed; • Transmit, to at least one slave microcontroller, an updated balancing request based on the estimated remaining balancing times.

[0021] According to a non-limiting implementation of the invention, prior to the step of switching off the master microcontroller, the method comprises a step of transmitting to at least one slave microcontroller, a request for voltage balancing at the terminals of first and second cells supervised by said at least one slave microcontroller, said balancing request comprising, • For each first cell supervised by said at least one slave microcontroller, a first balancing duration of said first cell to be carried out is determined, and • For each second cell supervised by said at least one slave microcontroller, a second balancing duration of said second cell to be carried out is determined.

[0022] Another aspect of the invention relates to a master microcontroller of a vehicle, the master microcontroller being arranged to execute the steps of the method according to any one of the preceding implementations.

[0023] Another aspect of the invention relates to an electric or hybrid vehicle comprising a battery comprising an alternation of first and second cells, a plurality of slave microcontrollers, each slave microcontroller being capable of supervising a group of first and second cells, the vehicle comprising a master microcontroller according to the previous implementation.

[0024] According to a non-limiting implementation of the invention, each slave microcontroller is formed by a cell supervision circuit.

[0025] Another aspect of the invention relates to a computer program product downloadable from a communications network and / or recorded on a computer-readable medium and / or executable by a processor, said computer program product comprising program code instructions for implementing the method according to any one of the aforementioned implementations, when the program is executed on a computer.

[0026] The invention and its various applications will be better understood upon reading the following description and examining the accompanying figures.

[0027] [Fig-1] illustrates, schematically, a voltage balancing at the terminals of first and second cells of a battery of an electric vehicle according to the prior art.

[0028] [Fig.2] illustrates, schematically, an electric vehicle according to an implementation non-limiting work of the invention.

[0029] [Fig.3] illustrates, schematically, a method according to a non-limited implementation miative of the invention.

[0030] [Fig.4] illustrates, schematically, voltage balancing durations at the terminals of first and second cells to be carried out by four slave microcontrollers according to a non-limiting implementation of the invention.

[0031] [Fig.5] illustrates, schematically, a balancing duration carried out with each of the first and second cells illustrated in [Fig.4].

[0032] The figures are presented for information purposes only and in no way limit the invention.

[0033] Unless otherwise specified, the same element appearing in different figures has a single reference.

[0034] [Fig. 2] illustrates an electric vehicle 1 comprising a battery 2 provided with a plurality of first cells C1 (also referred to as odd cells in the literature) and second cells C2 (also referred to as even cells in the literature). According to another non-limiting embodiment, the first cells C1 may form even cells and the second cells C2 may form odd cells.

[0035] The vehicle 1 also comprises four slave microcontrollers 3b 32, 33, 34. Each slave microcontroller 3b 32, 33, 34 is capable of supervising, in the example illustrated, three first cells C1 and three second cells C2. Each slave microcontroller 3b 32, 33, 34 may be formed by an integrated circuit specific to an application, also referred to as ASIC (for Application-Specific Integrated Circuit in English). According to another non-limiting example, each slave microcontroller 3b 32, 3 3, 34 may be formed by a cell supervision circuit, also referred to as CSC (for Cells Supervisor Circuit in English).

[0036] The vehicle 1 further comprises a master microcontroller 4 configured to execute the steps of the method 100 for estimating a progress status of a voltage balancing carried out at the terminals of the first and second cells C1, C2. This master microcontroller 4 can be formed by an engine computer.

[0037] The vehicle 1 further comprises a non-volatile memory 5. This non-volatile memory 5 may, for example and in a non-limiting manner, belong to the master microcontroller 4.

[0038] The method 100 according to the invention illustrated in [Fig.3] comprises a first step of receiving 101 a request to switch off the master microcontroller 4.

[0039] When the shutdown request is received by the master microcontroller 4, the latter executes a step of determining 102, for each slave microcontroller 3i, 32, 33, 34, and • For each first cell Cl supervised by said slave microcontroller 31, 32, 33, 34, a first balancing duration of said first cell Cl to be carried out, and • For each second cell C2 supervised by said slave microcontroller 31, 32, 33, 34, a second balancing duration of said second cell C2 to be carried out.

[0040] For example, in the example illustrated in [Fig.3], the first and second cells C1, C2 associated with the first slave microcontroller 3i have: • A balancing time to be carried out of 175 minutes for the first Cl cell, 115 minutes for the second Cl cell and 95 minutes for the third Cl cell; and • A balancing time of 95 minutes for the first second cell C2, 35 minutes for the second second cell C2 and 75 minutes for the third second cell C2.

[0041] The first and second cells C1, C2 associated with the second slave microcontroller 32 have: • A balancing time of 115 minutes for the first time cell Cl, 55 minutes for the second first cell Cl and 95 minutes for the third first cell Cl; and • A balancing time of 55 minutes for the first second cell C2, 95 minutes for the second second cell C2 and 175 minutes for the third second cell C2.

[0042] The first and second cells C1, C2 associated with the third slave microcontroller 33 have: • A balancing time to be carried out of 55 minutes for the first Cl cell, 35 minutes for the second Cl cell and 15 minutes for the third Cl cell; and • A balancing time of 75 minutes for the first second cell C2, 95 minutes for the second second cell C2 and 55 minutes for the third second cell C2.

[0043] The first and second cells C1, C2 associated with the fourth slave microcontroller 34 have: • A balancing time to be carried out of 175 minutes for the first Cl cell, 115 minutes for the second Cl cell and 95 minutes for the third Cl cell; and • A balancing time of 55 minutes for the first second cell C2, 95 minutes for the second second cell C2 and 175 minutes for the third second cell C2.

[0044] According to an optional and non-limiting implementation, the method 100 comprises a step of transmitting 103 to each slave microcontroller 3b 32, 33, 34, a balancing request RH R2, R3, R4 of voltage at the terminals of first and second cells C1, C2 supervised by a slave microcontroller 3b 32, 33, 34, said balancing request RH R2, R3, R4 comprising, • For each first cell C1 supervised by a slave microcontroller 31, 32, 33, 34, a first balancing duration of said first cell C1 to be carried out determined, and • For each second cell C2 supervised by said slave microcontroller 31, 32, 33, 34, a second balancing duration of said second cell C2 to be carried out is determined.

[0045] The method 100 also comprises a step of recording 104 a switching-off time of the master microcontroller 4 as well as the first and second balancing durations to be carried out in a non-volatile memory 5. The master microcontroller 4 is then switched off 105.

[0046] It should be noted that, in the usual way, to carry out the balancing of the first and second cells C1, C2, each of the microcontrollers 3i, 32, 33, 34 controls the opening or closing of a transistor so as to allow a flow of current from one cell to another neighboring cell. The balancing of the first cells C1 cannot be carried out simultaneously with the balancing of the second cells C2. Thus, the balancing is carried out alternately on the first cells C1, then on the second cells C2 according to a predetermined period, for example 5 seconds. Thus, as illustrated in [Fig.l], for a balancing request comprising a balancing of 100 minutes of the first cells C1 and 20 minutes of the second cells C2, a total balancing time of 120 minutes is obtained for the first and second cells C1, C2 supervised by the slave microcontroller.

[0047] When the master microcontroller 4 receives a wake-up request, the method 100 comprises a step of determining 106 a progress status of the balancing executed by the four slave microcontrollers 3b 32, 33, 34.

[0048] The progress status is determined as a function of the first and second balancing durations to be performed recorded, a shutdown duration of the master microcontroller 4 depending on the switching-off time and a wake-up time of the master microcontroller 4.

[0049] According to a non-limiting embodiment, the step of determining 106 a progress status of the executed balancing comprises a step, for each slave microcontroller 3i, 32, 33, 34, of selecting 106a from among the first cells C1 supervised by the slave microcontroller a first maximum balancing duration and from among the second cells C2 supervised by the slave microcontroller a second maximum balancing duration.

[0050] In the illustrated example, • For the first slave microcontroller 31, the first maximum balancing time is 175 minutes and the second maximum balancing time is 95 minutes; • For the second slave microcontroller 32, the first maximum balancing time is 115 minutes and the second maximum balancing time is 175 minutes; • For the third slave microcontroller 33, the first maximum balancing time is 55 minutes and the second maximum balancing time is 95 minutes; • For the fourth slave microcontroller 34, the first maximum balancing time is 175 minutes and the second maximum balancing time is 175 minutes.

[0051] The step of determining 106 a progress status of the executed balancing further comprises a step, for each slave microcontroller 3i, 32, 33, 34, of determining 106b a maximum overall balancing duration equal to the addition of the first maximum balancing duration with the second maximum balancing duration selected.

[0052] In the illustrated example, • The maximum overall balancing time for the 3i slave microcontroller is 175 minutes + 95 minutes, or 270 minutes; • The maximum overall balancing time for the 32 slave microcontroller is 115 minutes + 175 minutes, or 290 minutes; • The maximum overall balancing time for the slave microcontroller 33 is 55 minutes + 95 minutes, or 150 minutes; • The maximum overall balancing time for the slave microcontroller 34 is 175 minutes + 175 minutes, or 350 minutes.

[0053] For each slave microcontroller 3b 32, 33, 34, if the shutdown duration of the master microcontroller 4 is greater than the maximum overall balancing duration, the step of determining 106 a progress status of the balancing executed further comprises a step of determining 106c the completion of the balancing executed by the slave microcontroller 3i, 32, 33, 34.

[0054] If we take a shutdown time of the master microcontroller 4 of 241 minutes determined by means of the recorded shutdown time and the wake-up time of the master microcontroller 4, the overall balancing time for the slave microcontroller 33 of 150 minutes is less than 241 minutes. Thus, the master microcontroller 4 determines 106c the completion of the balancing executed by the slave microcontroller 3 3-

[0055] For the slave microcontrollers 3b 32, 34, since the shutdown duration of the master microcontroller 4 is less than the maximum overall balancing duration, the step of determining 106 a progress status of the executed balancing comprises a step of estimating 106d for each first and second cell C1, C2 a balancing duration carried out during the shutdown of the master microcontroller 4.

[0056] For the slave microcontroller 3i for which the shutdown duration of the master microcontroller 4 of 241 minutes is less than the maximum overall balancing duration of 270 minutes, the step of estimating 106d for each first and second cell C1, C2 a balancing duration carried out during the shutdown of the master microcontroller 4 comprises the step of determining 106di a first balancing duration allocated to the first cells C1 equal to the shutdown duration of the master microcontroller 4 divided by two, the decimal of which is rounded up to the next higher integer, and a second balancing duration allocated to the second cells C2 equal to the shutdown duration of the master microcontroller 4 divided by two, the decimal of which is considered to be zero, in other words the decimal of which is equal to zero.

[0057] In the example illustrated, if the shutdown duration of the master microcontroller 4 is 241 minutes: • The first balancing time allocated to the first Cl cells is 121 minutes ; • The second balancing time allocated to the second C2 cells is 120 minutes.

[0058] As the first balancing duration allocated to the first cells C1 of 121 minutes is less than the first maximum balancing duration of 175 minutes and the second balancing duration allocated to the second cells C2 of 120 minutes is greater than the second maximum balancing duration of 95 minutes, the step of estimating 106d, comprises a step of determining 106d2 a maximum balancing duration of the first cells C1 carried out.

[0059] This maximum balancing duration of the first cells C1 carried out is equal to the first balancing duration allocated to the first cells C1 of 121 minutes to which is added a second remainder of the second balancing duration allocated to the second cells C2 of 120 minutes not used. The second remainder is equal to the second balancing duration allocated to the second cells C2 of 120 minutes to which is subtracted the second maximum balancing duration of 95 minutes necessary for balancing the second cells C2, i.e. 25 minutes. Thus, the maximum balancing duration of the first cells C1 carried out is equal to 121 minutes + 25 minutes, i.e. 146 minutes.

[0060] The estimating step 106d also comprises a step 106d3 of determining a maximum balancing duration of the second cells C2 carried out equal to the second maximum balancing duration of 95 minutes.

[0061] The step of estimating 106d further comprises a step of determining 106d4 for each first cell Cl, a balancing duration performed equal to the minimum value between the first balancing duration of the first cell Cl to be performed and the maximum balancing duration of the first cells Cl performed.

[0062] Thus, as illustrated in [Fig.5], for the slave microcontroller 31, the balancing time carried out for the first first cell Cl is 146 minutes, for the second first cell Cl is 115 minutes and for the third first cell Cl is 95 minutes.

[0063] The step of estimating 106d further comprises a step of determining 106d5 for each second cell C2, a balancing duration performed equal to the minimum value between the second balancing duration of the second cell C2 to be performed and the maximum balancing duration of the second cells C2 performed.

[0064] Thus, as illustrated in [Fig.5], for the slave microcontroller 3i, the balancing time carried out for the first second cell C2 is 95 minutes, for the second second cell C2 is 35 minutes and for the third second cell C2 is 75 minutes.

[0065] For the slave microcontroller 32 for which the microcontroller shutdown duration master microcontroller 4 is less than the maximum overall balancing duration of 290 minutes, the step of estimating 106d, for each first and second cell Cl, C2 supervised by the slave microcontroller 32, a balancing duration carried out comprises the step of determining 106di a first balancing duration allocated to the first cells Cl equal to the stopping duration of the master microcontroller 4 divided by two, the decimal of which is rounded up to the next higher integer, and a second balancing duration allocated to the second cells C2 equal to the stopping duration of the master microcontroller 4 divided by two, the decimal of which is considered to be zero, in other words the decimal of which is equal to zero.

[0066] Since the first balancing duration allocated to the first cells C1 of 121 minutes is greater than the first maximum balancing duration of 115 minutes and the second balancing duration allocated to the second cells C2 of 120 minutes is less than the second maximum balancing duration of 175 minutes, the step of estimating 106d, comprises a step of determining 106d6 a maximum balancing duration of the first cells C1 carried out. This maximum balancing duration of the first cells C1 carried out is equal to the first maximum balancing duration, i.e. 115 minutes.

[0067] The step of estimating 106d, comprises a step of determining 106d7 a maximum balancing duration of the second cells C2 carried out.

[0068] This maximum balancing duration of the second cells C2 carried out is equal to the second balancing duration allocated to the second cells C2 of 120 minutes to which is added a first remainder of the first balancing duration allocated to the first cells C1 of 121 minutes not used. The first remainder is equal to the first balancing duration allocated to the first cells C1 of 121 minutes from which is subtracted the first maximum balancing duration of 115 minutes necessary for the balancing of the first cells C1, i.e. 6 minutes. Thus, the maximum balancing duration of the second cells C2 carried out is equal to 120 minutes + 6 minutes, i.e. 126 minutes.

[0069] The step of estimating 106d further comprises a step of determining 106d4 for each first cell Cl, a balancing duration performed equal to the minimum value between the first balancing duration of the first cell Cl to be performed and the maximum balancing duration of the first cells Cl performed.

[0070] Thus, as illustrated in [Fig.5], for the slave microcontroller 32, the balancing time carried out for the first first cell Cl is 115 minutes, for the second first cell Cl is 55 minutes and for the third first cell Cl is 95 minutes.

[0071] The step of estimating 106d further comprises a step of determining 106d5 for each second cell C2, a balancing duration carried out equal to the value minimum between the second balancing duration of the second C2 cell to be carried out and the maximum balancing duration of the second C2 cells carried out.

[0072] Thus, as illustrated in [Fig.5], for the slave microcontroller 32, the balancing time carried out for the first second cell C2 is 55 minutes, for the second second cell C2 is 95 minutes and for the third second cell C2 is 126 minutes.

[0073] For the slave microcontroller 34 for which the shutdown duration of the master microcontroller 4 of 241 minutes is less than the maximum overall balancing duration of 350 minutes, the step of estimating 106d for each first and second cell C1, C2 supervised by the slave microcontroller 34 a balancing duration carried out during the shutdown of the master microcontroller 4 comprises the step of determining 106di a first balancing duration allocated to the first cells C1 equal to the shutdown duration of the master microcontroller 4 divided by two, the decimal of which is rounded up to the next higher integer, and a second balancing duration allocated to the second cells C2 equal to the shutdown duration of the master microcontroller 4 divided by two, the decimal of which is considered to be zero, in other words the decimal of which is equal to zero.

[0074] As the first balancing duration allocated to the first cells C1 of 121 minutes is less than the first maximum balancing duration of 175 minutes and the second balancing duration allocated to the second cells C2 of 120 minutes is less than the second maximum balancing duration of 175 minutes, the step of estimating 106d, comprises a step of determining 106d8 a maximum balancing duration of the first cells C1 carried out.

[0075] This maximum balancing duration of the first Cl cells carried out is equal to the first balancing duration allocated to the first Cl cells, i.e. 121 minutes.

[0076] The step of estimating 106d, further comprises a step of determining 106d9 a maximum balancing duration of the second cells C2 carried out.

[0077] This maximum balancing duration of the second C2 cells carried out is equal to the second balancing duration allocated to the second C2 cells, i.e. 120 minutes.

[0078] The step of estimating 106d further comprises a step of determining 106d4 for each first cell Cl, a balancing duration performed equal to the minimum value between the first balancing duration of the first cell Cl to be performed and the maximum balancing duration of the first cells Cl performed.

[0079] Thus, as illustrated in [Fig.5], for the slave microcontroller 34, the balancing time carried out for the first first cell Cl is 121 minutes, for the second first cell Cl is 115 minutes and for the third first cell Cl is 95 minutes.

[0080] The step of estimating 106d further comprises a step of determining 106d5 for each second cell C2, a balancing duration carried out equal to the value minimum between the second balancing duration of the second C2 cell to be carried out and the maximum balancing duration of the second C2 cells carried out.

[0081] Thus, as illustrated in [Fig.5], for the slave microcontroller 34, the balancing time carried out for the first second cell C2 is 55 minutes, for the second second cell C2 is 95 minutes and for the third second cell C2 is 120 minutes.

[0082] According to a non-limiting aspect of the invention, if the shutdown duration of the master microcontroller 4 is less than the maximum overall balancing duration, the method 100 comprises, for each slave microcontroller 3b 32, 34, a step of estimating 107 for each first cell C1 and each second cell C2, a remaining balancing duration. The remaining balancing duration is a function of: • For each first cell Cl, the balancing duration carried out by said first cell Cl and the first balancing duration of said first cell Cl to be carried out; • For each second cell C2, the balancing duration performed by said second cell C2 and the second balancing duration of said second cell C2 to be performed.

[0083] The method 100 further comprises a step of transmitting 108, to the slave microcontrollers 3i, 32, 34, a balancing request updated as a function of the estimated remaining balancing durations.

Claims

Claims

1. Method (100) for estimating a progress status of a voltage balancing carried out at the terminals of cells (Cl, C2) of a battery (2) of an electric or hybrid vehicle (1), the cells (Cl, C2) being arranged by an alternation of first and second cells (Cl, C2), said vehicle (1) comprising a plurality of slave microcontrollers (3i, 32, 33, 34), each slave microcontroller (3i, 32, 33, 34) being capable of supervising a group of first and second cells (Cl, C2), said method (100) comprising the steps executed, by a master microcontroller (4), of: • Receive (101) a request to shut down said master microcontroller (4); • Determine (102) for each slave microcontroller (3b 32, 33, 34), and • For each first cell (Cl) supervised by said slave microcontroller (3b 32, 33, 34), a first balancing duration of said first cell (Cl) to be carried out, and • For each second cell (C2) supervised by said slave microcontroller (3b 32, 33, 34), a second balancing duration of said second cell (C2) to be carried out; • Record (104) a time of switching off of said master microcontroller (4) and the first and second balancing durations to be carried out by each slave microcontroller (3i, 32, 33, 34) in a non-volatile memory (5); • Turn off (105) said master microcontroller (4); • When said master microcontroller (4) receives a wake-up request, determining (106) a progress status of the balancing executed by each slave microcontroller (3i, 32, 33, 34), said progress status being a function of the first and second balancing durations to be carried out recorded, a shutdown duration of the master microcontroller (4) as a function of said shutdown time and a wake-up time of said master microcontroller (4).

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3.

4. Method (100) according to the preceding claim, characterized in that the step of determining (106) a progress status of the balancing executed comprises the steps, for each slave microcontroller (3b 3 2, 33, 34), of: - Select (106a), from among the first cells (Cl), a first maximum balancing duration and, from among the second cells (C2), a second maximum balancing duration; - Determine (106b) a maximum overall balancing duration equal to the addition of said first maximum balancing duration with said second selected maximum balancing duration; - If the master microcontroller (4) shutdown time is greater than the maximum overall balancing time, determine (106c) the completion of the balancing performed by the slave microcontroller (3b 32, 33, 34). Method (100) according to any one of claims 1 or 2, characterized in that the step of determining (106) a progress status of the balancing executed comprises the steps, for each slave microcontroller (3b 32, 33, 34), of: - Select (106a), from among the first cells (Cl), a first maximum balancing duration and, from among the second cells (C2), a second maximum balancing duration; - Determine (106b) a maximum overall balancing duration equal to the addition of said first maximum balancing duration with said second selected maximum balancing duration; - If the shutdown duration of the master microcontroller (4) is less than the maximum overall balancing duration, estimate (106d) for each first cell (Cl) and each second cell (C2), a balancing duration carried out during the shutdown of the master microcontroller (4). Method (100) according to the preceding claim, characterized in that, the step of estimating (106d), for each first cell (Cl) and each second cell (C2), a balancing duration carried out during the shutdown of the master microcontroller (4) comprises the steps of: - Determine (106di) a first balancing duration allocated to the first cells (Cl) equal to the stopping duration of the master microcontroller (4) divided by two, the possible decimal of which is rounded up to the next higher integer, and a second balancing duration allocated to the second cells (C2) equal to the stopping duration of the master microcontroller (4) divided by two, the possible decimal of which is considered to be zero; - If the first balancing time allocated to the first cells (Cl) is less than the first maximum balancing time and the second balancing time allocated to the second cells (C2) is less than the second maximum balancing time, • Determine (106d8) a maximum balancing duration of the first cells (Cl) carried out equal to the first balancing duration allocated to the first cells (Cl); • Determine (106d9) a maximum balancing duration of the second cells (C2) carried out equal to the second balancing duration allocated to the second cells (C2); • Determine (106d4) for each first cell (Cl), a balancing duration performed equal to the minimum value between the first balancing duration of said first cell (Cl) to be performed and the maximum balancing duration of the first cells (Cl) performed: • Determine (106d5) for each second cell (C2), a balancing duration performed equal to the minimum value between the second balancing duration of said second cell (C2) to be performed and the maximum balancing duration of the second cells (C2) performed.

5. Method (100) according to claim 3, characterized in that the step of estimating (106d), for each first cell (Cl) and each second cell (C2), a balancing duration carried out during the shutdown of the master microcontroller (4) comprises the steps of: - Determine (106di) a first balancing duration allocated to the first cells (Cl) equal to the stopping duration of the master microcontroller (4) divided by two, the possible decimal of which is rounded up to the next higher integer, and a second balancing duration allocated to the second cells (C2) equal to the stopping duration of the master microcontroller (4) divided by two, the possible decimal of which is considered to be zero; - If the first balancing duration allocated to the first cells (Cl) is less than the first maximum balancing duration and the second balancing duration allocated to the second cells (C2) is greater than the second maximum balancing duration, • Determine (106d2) a maximum balancing duration of the first cells (Cl) carried out equal to the first balancing duration allocated to the first cells (Cl) to which is added a second remainder of the second balancing duration allocated to the second cells (C2) not used, said second remainder being equal to the second balancing duration allocated to the second cells (C2) from which is subtracted the second maximum balancing duration; • Determine (106d3) a maximum balancing duration of the second cells (C2) carried out equal to the second maximum balancing duration; • Determine (106d4) for each first cell (Cl), a balancing duration performed equal to the minimum value between the first balancing duration of said first cell (Cl) to be performed and the maximum balancing duration of the first cells (Cl) performed: • Determine (106d5) for each second cell

6. (C2), a balancing duration performed equal to the minimum value between the second balancing duration of said second cell (C2) to be performed and the maximum balancing duration of the second cells (C2) performed. Method (100) according to claim 3, characterized in that the step of estimating (106d), for each first cell (Cl) and each second cell (C2), a balancing duration carried out during the shutdown of the master microcontroller (4) comprises the steps of: - Determine (106di) a first balancing duration allocated to the first cells (Cl) equal to the stopping duration of the master microcontroller (4) divided by two, the possible decimal of which is rounded up to the next higher integer, and a second balancing duration allocated to the second cells (C2) equal to the stopping duration of the master microcontroller (4) divided by two, the possible decimal of which is considered to be zero; - If the first balancing time allocated to the first cells (Cl) is greater than the first maximum balancing time and the second balancing time allocated to the second cells (C2) is less than the second maximum balancing time, • Determine (106d6) a maximum balancing duration of the first cells (Cl) carried out equal to the first maximum balancing duration; • Determine (106d7) a maximum balancing duration of the second cells (C2) carried out equal to the second balancing duration allocated to the second cells (C2) to which is added a first remainder of the first balancing duration allocated to the first cells (Cl) not used, said first remainder being equal to the first balancing duration allocated to the first cells (Cl) from which is subtracted the first maximum balancing duration; • Determine (106d4), for each first cell (Cl), a balancing duration carried out equal to the minimum value between the first balancing duration of said first cell (Cl) to be carried out and the maximum balancing duration of the first cells (Cl) carried out. Determine (106d5) for each second cell (C2), a balancing duration performed equal to the minimum value between the second balancing duration of said second cell (C2) to be performed and the maximum balancing duration of the second cells (C2) performed.

7.

8. Method (100) according to any one of claims 3 to 6, characterized in that it comprises, for each slave microcontroller (3b 32, 33, 34), the steps of: - Estimate (107) for each first cell (Cl) and each second cell (C2), a remaining balancing duration, said remaining balancing duration being a function of: • For each first cell (Cl), the balancing duration carried out by said first cell (Cl) during the shutdown of the master microcontroller (4) and the first balancing duration of said first cell (Cl) to be carried out; • For each second cell (C2), the balancing duration performed by said second cell (C2) during the shutdown of the master microcontroller (4) and the second balancing duration of said second cell (C2) to be performed; - Transmit (108), to at least one slave microcontroller (3i, 32, 33, 34), a balancing request updated according to the estimated remaining balancing times. Method (100) according to any one of the preceding claims, characterized in that, prior to the step of switching off (105) the master microcontroller (4), the method (100) comprises a step of transmitting (103) to at least one slave microcontroller (3b 32, 33, 34), a balancing request (Rb R2, R3, R4) of voltage at the terminals of first and second cells (Cl, C2) supervised by said at least one slave microcontroller (3b 32, 33, 34), said balancing request (Ri, R2, R3, R4) comprising, - For each first cell (Cl) supervised by said at least one slave microcontroller (3b 32, 33, 34), a first balancing duration of said first cell (Cl) to be carried out, and - For each second cell (C2) supervised by said at least one slave microcontroller (3b 32, 33, 34), a second balancing duration of said second cell (C2) to be carried out.

9. Master microcontroller (4) of a vehicle (1), characterized in that it is arranged to execute the steps of the method (100) according to any one of the preceding claims.

10. Electric or hybrid vehicle (1) comprising a battery (2) comprising an alternation of first and second cells (Cl, C2), a plurality of slave microcontrollers (3i, 32, 33, 34), each slave microcontroller (3i, 32, 33, 34) being capable of supervising a group of first and second cells (Cl, C2), said vehicle (1) being characterized in that it comprises a master microcontroller (4) according to the preceding claim.

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