Method for estimating a state of progress of a voltage balancing operation performed 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 state of progress of a voltage balancing operation performed at the terminals of the cells of a battery of an electric or hybrid vehicle, wherein the cells are arranged as alternating first and second cells, and wherein the vehicle comprises a plurality of slave microcontrollers, each slave microcontroller being able to supervise a group of first and second cells; the method (100), when the master microcontroller receives a wake-up request, performs a step of determining (106) a state of progress of the balancing operation performed by at least one slave microcontroller, wherein the state of progress is dependent on recorded first and second balancing periods to be carried out, and a duration for which the master microcontroller is off, based on a switch-off time and a wake-up time of the master microcontroller.

Description

DESCRIPTION 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 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 plug-in hybrid vehicle comprises an electric storage battery made up of a large number of cells in series and / or parallel. While all the cells in a storage battery have similar characteristics, there are nevertheless variations or differences, particularly physical ones, such as a variation in capacity in Ampere-hours (Ah) and resistance in ohms (Q). There are also variations, generally temporary, in the states of these cells, such as the difference in state of charge, generally called SOC (State Of Charge), and / or temperature.

[0003] Over time and with battery use, all these physical dispersions and state differences 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 (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] To overcome this drawback, it is known to balance the charge states of the cells on a regular basis. This balancing is ensured by a battery management system, known by the Anglo-Saxon 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 arranged between two first cells. Thus, the charging or discharging of a cell is controlled via the transfer of energy from a first cell to a second adjacent cell, or from a second cell to a first adjacent 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. Based on these voltage values, the master microcontroller determines for each cell 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 microcontrollers. 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 Figure 1, 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 balancing the first C1 cells until reaching one hundred minutes.

[0009] This balancing strategy is executed when the motor vehicle is asleep. "Asleep" refers to the state of a motor vehicle when it is stationary and most of the computers are switched off. 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 completed. To do this, the master microcontroller polls the slave microcontrollers to determine the duration of balancing 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 duration of balancing performed.

[0010] Additionally, when the vehicle is restarted, some vehicles require all slave microcontrollers to be reset. Thus, when the master microcontroller requests the progress of the balancing process from the slave microcontrollers, the latter have no data to transmit to it. Thus, the master microcontroller is unable 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 microcontrollers. This process is obviously lengthy. 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 vehicle battery 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; Recording 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, determining 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 shutdown duration of the master microcontroller as a function of said shutdown time and a wake-up time of the master microcontroller.

[0013] Thanks to the method according to the invention, when it wakes up, the master microcontroller is not dependent on the slave microcontrollers, nor even on the communication link with the latter, to determine a progress status of the balancing carried out during its sleep. Thus, if a 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 a balancing request. update 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 additional 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 balancing executed 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's shutdown time is greater than the maximum overall balancing time, determine the completion of 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 balancing executed 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 performed during the master microcontroller shutdown.

[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 time of the second cells performed equal to the second balancing time 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 less than the first maximum balancing time and the second balancing time allocated to the second cells is greater than the second maximum balancing time, 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 time of the first cells performed equal to the first maximum balancing time; Determine a maximum balancing duration of the second cells carried out equal to the second balancing duration allocated to the second cells to which is added a first remainder of the first balancing duration allocated to the first cells not used, said first remainder being equal to the first balancing duration allocated to the first cells from which is subtracted the first maximum balancing duration; 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 carried out equal to the minimum value between the second balancing duration of the second cell to perform and the maximum balancing time 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 duration performed by said first cell during the shutdown of the master microcontroller and the first balancing duration of said first cell to be performed; 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 by reading the following description and examining the accompanying figures.

[0027] [Fig. 1] schematically illustrates 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] schematically illustrates an electric vehicle according to a non-limiting implementation of the invention.

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

[0030] [Fig. 4] illustrates, schematically, voltage balancing times 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] schematically illustrates a balancing duration carried out on each of the first and second cells illustrated in Figure 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] Figure 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 can form even cells and the second cells C2 can form odd cells.

[0035] The vehicle 1 also comprises four slave microcontrollers 3i, 32, 3s, 34. Each slave microcontroller 3i, 32, 3s, 34 is capable of supervising, in the example illustrated, three first cells C1 and three second cells C2. Each slave microcontroller 3i, 32, 3s, 34 can 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 3i, 32, 3s, 34 can 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 figure 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, 3s, 34, and For each first cell C1 supervised by said slave microcontroller 31, 32, 33, 34, a first balancing duration of said first cell C1 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 Figure 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 first cell C1, 115 minutes for the second first cell C1 and 95 minutes for the third first cell C1; and A balancing time to be carried out 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 to be carried out of 115 minutes for the first first cell C1, 55 minutes for the second first cell C1 and 95 minutes for the third first cell C1; and A balancing time to be carried out 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 3s have: A balancing time to be carried out of 55 minutes for the first first cell C1, 35 minutes for the second first cell C1 and 15 minutes for the third first cell C1; and A balancing time to be carried out 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 first cell C1, 115 minutes for the second first cell C1 and 95 minutes for the third first cell C1; and A balancing time to be carried out 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 3i, 32, 3s, 34, a balancing request Ri, F, R3, R4 of voltage at the terminals of first and second cells C1, C2 supervised by a slave microcontroller 3i, 32, 3s, 34, said balancing request Ri, 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 is 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, 3s, 34 controls the opening or closing of the 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 Figure 1, for a balancing request comprising a balancing of 100 minutes of the first cells C1 and 20 minutes of the second cells C2, we obtain a total balancing time of the first and second cells C1, C2 supervised by the slave microcontroller of 120 minutes.

[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 3i, 32, 3s, 34.

[0048] The progress status is determined based on the first and second balancing times to be performed recorded, a shutdown time of the master microcontroller 4 depending on the switch-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, 3s, 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 3i slave microcontroller, the first maximum balance time is 175 minutes and the second maximum balance 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 3s slave microcontroller, 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, 3s, 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 slave microcontroller 31 is 175 minutes + 95 minutes, or 270 minutes; The maximum overall balancing time for the slave microcontroller 32 is 115 minutes + 175 minutes, or 290 minutes; The maximum overall balancing time for the 3s slave microcontroller is 55 minutes + 95 minutes, or 150 minutes; The maximum overall balancing time for the slave 34 microcontroller is 175 minutes + 175 minutes, or 350 minutes.

[0053] For each slave microcontroller 3i, 32, 3s, 34, if the stop 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, 3s, 34.

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

[0055] For the slave microcontrollers 3i, 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 shown, if the master microcontroller 4 shutdown time is 241 minutes: The first balancing time allocated to the first C1 cells is 121 minutes; The second balancing time allocated to the second C2 cells is 120 minutes.

[0058] Since 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 time of the first C1 cells carried out is equal to the first balancing time allocated to the first C1 cells of 121 minutes to which is added a second remainder of the second balancing time allocated to the second C2 cells of 120 minutes not used. The second remainder is equal to the second balancing time allocated to the second C2 cells of 120 minutes to which is subtracted the second maximum balancing time of 95 minutes necessary for balancing the second C2 cells, or 25 minutes. Thus, the maximum balancing time of the first C1 cells performed is equal to 121 minutes + 25 minutes, or 146 minutes.

[0060] The step of estimating 106d also includes a step of determining 106ds 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 C1, a balancing duration performed equal to the minimum value between the first balancing duration of the first cell C1 to be performed and the maximum balancing duration of the first cells C1 performed.

[0062] Thus, as illustrated in Figure 5, for the slave microcontroller 3i, the balancing time performed for the first first cell C1 is 146 minutes, for the second first cell C1 is 115 minutes and for the third first cell C1 is 95 minutes.

[0063] The step of estimating 106d further comprises a step of determining 106ds 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 Figure 5, for the slave microcontroller 3i, the balancing time performed 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 shutdown duration of the 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 C1, 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 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.

[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 106de 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, includes a step of determining 106d? a maximum balancing duration of the second cells C2 carried out.

[0068] This maximum balancing time of the second C2 cells carried out is equal to the second balancing time allocated to the second C2 cells of 120 minutes to which is added a first remainder of the first balancing time allocated to the first C1 cells of 121 minutes not used. The first remainder is equal to the first balancing time allocated to the first C1 cells of 121 minutes to which is subtracted the first maximum balancing time of 115 minutes necessary for balancing the first C1 cells, i.e. 6 minutes. Thus, the maximum balancing time of the second C2 cells 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 C1, a balancing duration performed equal to the minimum value between the first balancing duration of the first cell C1 to be performed and the maximum balancing duration of the first cells C1 performed.

[0070] Thus, as illustrated in Figure 5, for the slave microcontroller 32, the balancing time performed for the first first cell C1 is 115 minutes, for the second first cell C1 is 55 minutes and for the third first cell C1 is 95 minutes.

[0071] The step of estimating 106d further comprises a step of determining 106ds 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.

[0072] Thus, as illustrated in Figure 5, for the slave microcontroller 32, the balancing time performed 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] Since 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 106ds a maximum balancing duration of the first cells C1 carried out.

[0075] This maximum balancing time of the first C1 cells carried out is equal to the first balancing time allocated to the first C1 cells, i.e. 121 minutes.

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

[0077] This maximum balancing time of the second C2 cells carried out is equal to the second balancing time 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 C1, a balancing duration carried out equal to the minimum value between the first balancing time of the first C1 cell to be performed and the maximum balancing time of the first C1 cells performed.

[0079] Thus, as illustrated in Figure 5, for the slave microcontroller 34, the balancing time performed for the first first cell C1 is 121 minutes, for the second first cell C1 is 115 minutes and for the third first cell C1 is 95 minutes.

[0080] The step of estimating 106d further comprises a step of determining 106ds 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.

[0081] Thus, as illustrated in Figure 5, for the slave microcontroller 34, the balancing time performed 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 3i, 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 C1, the balancing duration performed by said first cell C1 and the first balancing duration of said first cell C1 to be performed; 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 times.

Claims

CLAIMS

1. Method (100) for estimating a progress status of a voltage balancing carried out at the terminals of cells (C1, C2) of a battery (2) of an electric or hybrid vehicle (1), the cells (C1, C2) being arranged by an alternation of first and second cells (C1, C2), said vehicle (1) comprising a plurality of slave microcontrollers (3i, 32, 3s, 34), each slave microcontroller (3i, 32, 3s, 34) being capable of supervising a group of first and second cells (C1, C2), said method (100) comprising the steps executed, by a master microcontroller (4), of: Receive (101) a request to turn off said master microcontroller (4); Determine (102) for each slave microcontroller (3i, 32, 3s, 34), and For each first cell (C1) supervised by said slave microcontroller (3i, 32, 3s, 34), a first balancing duration of said first cell (C1) to be carried out, and For each second cell (C2) supervised by said slave microcontroller (3i, 32, 3s, 34), a second balancing duration of said second cell (C2) to be carried out; - balancing being carried out alternately on each first cell C1, then on each second cell C2 according to a predetermined period, Recording (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, 3s, 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, 3s, 34), said progress status being a function of the first and second balancing durations to be carried out recorded, of a shutdown duration of the master microcontroller (4) depending on said switching-off time and a waking-up time of said master microcontroller (4), transmit (108), to the slave microcontrollers, a balancing request updated according to the estimated remaining balancing times.

2. Method (100) according to the preceding claim, characterized in that the step of determining (106) a progress status of the executed balancing comprises the steps, for each slave microcontroller (3i, 32, 3s, 34), of: - Select (106a), from among the first cells (C1), 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 (3i, 32, 3s, 34).

3. Method (100) according to any one of claims 1 or 2, characterized in that the step of determining (106) a progress status of the executed balancing comprises the steps, for each slave microcontroller (3i, 82, 3s, 84), of: - Select (106a), from among the first cells (C1), 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 less than the maximum overall balancing time, estimate (106d) for each first cell (C1) and each second cell (C2), a balancing duration carried out during the shutdown of the master microcontroller (4).

4. Method (100) according to the preceding claim, characterized in that the step of estimating (106d), for each first cell (C1) 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 (C1) 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 (C1) is less than the first maximum balancing duration and the second balancing duration allocated to the second cells (C2) is less than the second maximum balancing duration, o Determine (106ds) a maximum balancing duration of the first cells (C1) carried out equal to the first balancing duration allocated to the first cells (C1); o Determine (106dg) a maximum balancing duration of the second cells (C2) carried out equal to the second balancing duration allocated to the second cells (C2);o Determine (106d4) for each first cell (C1), a balancing duration performed equal to the minimum value between the first balancing duration of said first cell (C1) to be performed and the maximum balancing duration of the first cells (C1) performed: o Determine (106ds) 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 time 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 (C1) 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 (C1) 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 (C1) 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, o Determine (106d2) a maximum balancing duration of the first cells (C1) carried out equal to the first balancing duration allocated to the first cells (C1) 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; o Determine (106ds) a maximum balancing duration of the second cells (C2) carried out equal to the second maximum balancing duration;o Determine (106d4) for each first cell (C1), a balancing duration performed equal to the minimum value between the first balancing duration of said first cell (C1); to be carried out and the maximum balancing duration of the first cells (C1) carried out: o Determine (106ds) for each second cell (C2), a balancing duration carried out equal to the minimum value between the second balancing duration of said second cell (C2) to be carried out and the maximum balancing duration of the second cells (C2) carried out.

6. Method (100) according to claim 3, characterized in that the step of estimating (106d), for each first cell (C1) 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 (C1) 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 (C1) is greater than the first maximum balancing duration and the second balancing duration allocated to the second cells (C2) is less than the second maximum balancing duration, o Determine (106de) a maximum balancing duration of the first cells (C1) carried out equal to the first maximum balancing duration; o Determine (106d?) 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 (C1) not used, said first remainder being equal to the first duration balancing time allocated to the first cells (C1) from which the first maximum balancing time is subtracted; o Determine (106d4), for each first cell (C1), a balancing time performed equal to the minimum value between the first balancing time of said first cell (C1) to be performed and the maximum balancing time of the first cells (C1) performed. o Determine (106ds) for each second cell (C2), a balancing time performed equal to the minimum value between the second balancing time of said second cell (C2) to be performed and the maximum balancing time of the second cells (C2) performed.

7. Method (100) according to any one of claims 3 to 6, characterized in that it comprises, for each slave microcontroller (3i, 32, 3s, 34), the steps of: - Estimate (107) for each first cell (C1) and each second cell (C2), a remaining balancing duration, said remaining balancing duration being a function: o For each first cell (C1), of the balancing duration performed by said first cell (C1) during the shutdown of the master microcontroller (4) and of the first balancing duration of said first cell (C1) to be performed; o For each second cell (C2), of the balancing duration performed by said second cell (C2) during the shutdown of the master microcontroller (4) and of the second balancing duration of said second cell (C2) to be performed; - Transmit (108), to at least one slave microcontroller (3i, 32, 3s, 34), a balancing request updated according to the estimated remaining balancing times. [Claim s] Method (100) according to any one of the preceding claims, characterized in that, prior to the step of extinguishing (105) the Tl master microcontroller (4), the method (100) comprises a step of transmitting (103) to at least one slave microcontroller (3i, 32, 3s, 34), a balancing request (Ri, R2, R3, R4) of voltage at the terminals of first and second cells (C1, C2) supervised by said at least one slave microcontroller (3i, 32, 3s, 34), said balancing request (Ri, R2, R3, R4) comprising, - For each first cell (C1) supervised by said at least one slave microcontroller (3i, 32, 3s, 34), a first balancing duration of said first cell (C1) to be carried out, and - For each second cell (C2) supervised by said at least one slave microcontroller (3i, 32, 3s, 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 (C1, C2), a plurality of slave microcontrollers (3i, 32, 3s, 34), each slave microcontroller (3i, 32, 3s, 34) being capable of supervising a group of first and second cells (C1, C2), said vehicle (1) being characterized in that it comprises a master microcontroller (4) according to the preceding claim.

Images