METHOD FOR ESTIMATING THE PROGRESS OF A VOLTAGE BALANCING PERFORMED AT THE TERMINALS OF CELLS IN A BATTERY OF AN ELECTRIC OR HYBRID VEHICLE

Abstract

One aspect of the invention relates to a method 100 for estimating the progress of voltage balancing performed across the cells of a battery in an electric or hybrid vehicle, the cells being arranged in alternating 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 performs a step of determining 106 the progress of the balancing performed by at least one slave microcontroller, said progress being a function of the first and second balancing times to be performed, a shutdown time of the master microcontroller that is a function of a power-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 PERFORMED AT THE TERMINALS OF CELLS IN A BATTERY OF AN ELECTRIC OR HYBRID VEHICLE. TECHNICAL FIELD OF THE INVENTION

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

[0002] An electric, hybrid, or plug-in hybrid vehicle comprises an electric battery made up of a large number of cells connected in series and / or parallel. While all the cells in a battery have similar characteristics, there are nevertheless variations or differences, particularly physical ones, such as variations 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 differences in state of charge, commonly referred to as SOC (State of Charge), and / or temperature.

[0003] Over time and with battery use, all these physical variations 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 (State of Health), which differs from one cell to another. The differences in state of health between cells connected in series are 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 lower the total usable capacity of the battery. This therefore has a negative impact on the range of the vehicle equipped with such a battery.

[0004] To overcome this drawback, it is known to balance the charge states of the cells regularly. This balancing is ensured by a battery management device, known by the English term Battery Management System (BMS).

[0005] Balancing can be achieved by transferring electrical energy from one cell to an adjacent cell via the control of transistors, for example MOSFETs. To achieve such balancing, it is usually considered that a first cell (or odd-numbered cell) is placed between two second cells (or even-numbered cells), and that a second cell is placed 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 arranged 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 the on / off 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 time for each first cell and a balancing time for each second cell.

[0008] Each slave microcontroller that has received a request then alternates, via transistor control, the balancing, for example every five seconds, between the first cells and the second cells whose charge state must be balanced. As illustrated in [Fig. 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 balancing the first cells C1 and the second cells C2 until it reaches the balancing time of twenty minutes for the second cells C2, then continues balancing the first cells C1 until it reaches one hundred minutes.

[0009] This balancing strategy is executed when the motor vehicle is asleep. "Asleep" refers to the state of a motor vehicle that is stationary and in which most of the control units are shut down. When the vehicle is asleep, the vehicle's master microcontroller is frequently woken up, for example, every four hours, to ensure that the balancing process being performed by the slave microcontrollers is completed. To do this, the master microcontroller queries the slave microcontrollers to determine the balancing time completed. However, if the connection between one of the slave microcontrollers and the master microcontroller is broken, the master microcontroller is unable to determine the balancing time completed.

[0010] Furthermore, 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 The slave microcontrollers have no data to transmit to the master microcontroller. Therefore, the master microcontroller cannot determine if the cell balancing process is complete. The slave microcontrollers must determine the voltage across each cell, transmit these voltage values ​​to the master microcontroller, which will then generate 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 the progress of a voltage balancing carried out at the terminals of cells of a vehicle battery which is not impacted by a failure of information transmission from one of the slave microcontrollers to the master microcontroller.

[0012] To this end, the invention relates, in its broadest sense, to a method for estimating the progress of voltage balancing performed across the terminals of cells in a battery of an electric or hybrid vehicle, the cells being arranged in alternating 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 request to shut down the master microcontroller; • Determine for each slave microcontroller, and • For each first cell monitored by said slave microcontroller, an initial balancing time for said first cell must be performed, and • For each second cell supervised by said slave microcontroller, a second balancing time of said second cell to be performed; • Record a moment of shutdown of said master microcontroller and the first and second balancing times to be performed 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 shutdown duration of the master microcontroller based on said shutdown time and a wake-up time of the master microcontroller.

[0013] Thanks to the method according to the invention, upon waking up, the master microcontroller is not dependent on the slave microcontrollers, nor even on the communication link with them, to determine the progress of the balancing performed 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 complete or not. If the balancing process is not complete, 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 mentioned in the preceding paragraph, the process according to the invention may have one or more complementary characteristics from 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 the progress of the balancing performed comprises the steps, for each slave microcontroller, of: • Select a first maximum balancing time from the first cells and a second maximum balancing time from the second cells; • Determine a maximum overall balancing time equal to the sum of the first maximum balancing time with the second maximum balancing time selected; • If the downtime of the master microcontroller 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 the progress of the balancing performed comprises the steps, for each slave microcontroller, of: • Select a first maximum balancing time from the first cells and a second maximum balancing time from the second cells; • Determine a maximum overall balancing time equal to the sum of said first maximum balancing time with said second maximum balancing time selected; • If the master microcontroller's downtime is less than the maximum overall balancing time, estimate for each first cell and every second cell, a balancing time performed while the master microcontroller is shut down.

[0017] According to a non-limiting implementation of the invention, the step of estimating, for each first cell and each second cell, a balancing time performed during the shutdown of the master microcontroller comprises the steps of: • Determine a first balancing time allocated to the first cells equal to the shutdown time of the master microcontroller divided by two, whose possible decimal is rounded up to the next integer, and a second balancing time allocated to the second cells equal to the shutdown time of the master microcontroller divided by two, whose possible decimal 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 time for the first cells performed equal to the first balancing time allocated to the first cells; • Determine a maximum balancing time for the second cells performed equal to the second balancing time allocated to the second cells; • Determine for each first cell, a balancing time performed equal to the minimum value between the first balancing time of the first cell to be performed and the maximum balancing time of the first cells performed; • Determine for each second cell, a balancing time performed equal to the minimum value between the second balancing time of the second cell to be performed and the maximum balancing time 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 time performed during the shutdown of the master microcontroller comprises the steps of: • Determine a first balancing time allocated to the first cells equal to the shutdown time of the master microcontroller divided by two, whose possible decimal is rounded up to the next integer, and a second balancing time allocated to the second cells equal to the shutdown time of the master microcontroller divided by two, whose possible decimal 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 time for the first cells performed equal to the first balancing time allocated to the first cells plus a second remainder of the second balancing time allocated to the second cells not used, said second remainder being equal to the second balancing time allocated to the second cells minus the second maximum balancing time; • Determine a maximum balancing time for the second set of cells performed equal to the second maximum balancing time; • Determine for each first cell, a balancing time performed equal to the minimum value between the first balancing time of the first cell to be performed and the maximum balancing time of the first cells performed; • Determine for each second cell, a balancing time performed equal to the minimum value between the second balancing time of the second cell to be performed and the maximum balancing time 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 time performed during the shutdown of the master microcontroller comprises the steps of: • Determine a first balancing time allocated to the first cells equal to the shutdown time of the master microcontroller divided by two, whose possible decimal is rounded up to the next integer, and a second balancing time allocated to the second cells equal to the shutdown time of the master microcontroller divided by two, whose possible decimal 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 for the first cells performed equal to the first maximum balancing time; • Determine a maximum balancing time for the second cells performed equal to the second balancing time allocated to the second cells plus a first remainder of the first balancing time allocated to the first cells not used, said first remainder being equal to the first balancing time allocated to the first cells minus the first maximum balancing time; • Determine for each first cell, a balancing time performed equal to the minimum value between the first balancing time of the first cell to be performed and the maximum balancing time of the first cells performed; • Determine for each second cell, a balancing time performed equal to the minimum value between the second balancing time of the second cell to be performed and the maximum balancing time of the second cells performed.

[0020] According to a non-limiting embodiment of the invention, the method comprises, for each slave microcontroller, the following steps: • 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 performed by said first cell during the shutdown of the master microcontroller and the first balancing time to be performed by said first cell; • For each second cell, the balancing time performed by said second cell during the shutdown of the master microcontroller and the second balancing time 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 embodiment of the invention, prior to the step of switching off the master microcontroller, the method includes a step of transmitting to at least one slave microcontroller a voltage balancing request across the 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 time to be performed for said first cell is determined, and • For each second cell supervised by said at least one slave microcontroller, a second balancing time of said second cell to be performed 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 process according to any one of the preceding implementations.

[0023] Another aspect of the invention relates to an electric or hybrid vehicle comprising a battery having 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 communication 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 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] illustrates, schematically, a voltage balancing across 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 a layout non-limiting work of the invention.

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

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

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

[0032] The figures are presented for illustrative purposes only and are in no way limiting of the invention.

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

[0034] Figure 2 illustrates an electric vehicle 1 comprising a battery 2 equipped with a plurality of first cells Cl (also referred to as odd cells in the literature) and second C2 cells (also referred to as paired cells in the literature). According to another non-limiting embodiment, the first Cl cells can form paired cells and the second C2 cells can form odd-numbered cells.

[0035] Vehicle 1 also includes four slave microcontrollers 3b 32, 33, 34. Each slave microcontroller 3i, 32, 33, 34 is capable of supervising, in the illustrated example, three first cells C1 and three second cells C2. Each slave microcontroller 3b 32, 33, 34 can be formed by an application-specific integrated circuit, also known as an ASIC (for Application-Specific Integrated Circuit). In another non-limiting example, each slave microcontroller 3i, 32, 33, 34 can be formed by a cell supervisor circuit, also known as a CSC (for Cell Supervisor Circuit).

[0036] The vehicle 1 further comprises a master microcontroller 4 configured to execute the steps of the method 100 for estimating the progress of a voltage balancing carried out across the terminals of the first and second cells Cl, 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 without limitation, belong to the master microcontroller 4.

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

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

[0040] For example, in the example illustrated in [Fig. 3], the first and second cells Cl, C2 associated with the first slave microcontroller 3i exhibit: • A balancing time 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 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 Cl, C2 associated with the second slave microcontroller 32 have: • A balancing time of 115 minutes for the first Cl cell, 55 minutes for the second Cl cell, and 95 minutes for the third Cl cell; 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 Cl, C2 associated with the third slave microcontroller 33 have: • A balancing time 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 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 Cl, C2 associated with the fourth slave microcontroller 34 have: • A balancing time 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 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 includes a step of transmitting 103 to each slave microcontroller 3i, 32, 33, 34, a voltage balancing request Rh R2, R3, R4 across the terminals of the first and second cells Cl, C2 supervised by a slave microcontroller 3b 32, 33, 34, said balancing request Rb R2, R3, R4 comprising, • For each first cell Cl supervised by a slave microcontroller 31, 32, 33, 34, a first balancing time of said first cell Cl to be performed is determined, and • For each second cell C2 supervised by said slave microcontroller 31, 32, 33, 34, a second balancing time of said second cell C2 to be performed determined.

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

[0046] It should be noted that, typically, to balance the first and second cells Cl, C2, each of the microcontrollers 3b 32, 33, 34 controls the opening or closing of a transistor to allow current to flow from one cell to a neighboring cell. Balancing the first cells Cl cannot be performed simultaneously with balancing the second cells C2. Thus, balancing is performed alternately on the first cells Cl, then on the second cells C2, according to a predetermined period, for example, 5 seconds. Thus, as illustrated in [Fig. 1], for a balancing request involving 100 minutes of balancing of the first cells Cl and 20 minutes of balancing of the second cells C2, the total balancing time for the first and second cells Cl, C2 supervised by the slave microcontroller is 120 minutes.

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

[0048] The progress state is determined according to the first and second balancing times to be performed recorded, a shutdown time of the master microcontroller 4 as a function of the shutdown 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 state of the executed balancing includes a step, for each slave microcontroller 3b 32, 33, 34, of selecting 106a from among the first cells Cl supervised by the slave microcontroller a first maximum balancing time and from among the second cells C2 supervised by the slave microcontroller a second maximum balancing time.

[0050] In the illustrated example, • For the first 3i slave microcontroller, 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 state of the executed balancing further includes a step, for each slave microcontroller 3b 32, 33, 34, of determining 106b a maximum overall balancing time equal to the sum of the first maximum balancing time with the second maximum balancing time 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 slave microcontroller 32 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 downtime of the master microcontroller 4 is greater than the maximum global balancing time, the step of determining 106 a progress state of the balancing performed further includes a step of determining 106c the completion of the balancing performed by the slave microcontroller 3i, 32, 33, 34.

[0054] If we take a shutdown time of 241 minutes for the master microcontroller 4, 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 as the completion of the balancing performed by the slave microcontroller 33.

[0055] For slave microcontrollers 3i, 32, 34, as the shutdown time of the master microcontroller 4 is less than the maximum global balancing time, the step of determining 106 a progress state of the balancing performed includes a step of estimating 106d for each first and second cell Cl, C2 a balancing time performed during the shutdown of the master microcontroller 4.

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

[0057] In the illustrated example, if the shutdown time 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] Since the first balancing time allocated to the first Cl cells of 121 minutes is less than the first maximum balancing time of 175 minutes and the second balancing time allocated to the second C2 cells of 120 minutes is greater than the second maximum balancing time of 95 minutes, the step of estimating 106d includes a step of determining 106d2 a maximum balancing time of the first Cl cells carried out.

[0059] This maximum balancing time for the first C1 cells is equal to the first balancing time allocated to the first C1 cells (121 minutes) plus a second unused portion of the second balancing time allocated to the second C2 cells (120 minutes). This second portion is equal to the second balancing time allocated to the second C2 cells (120 minutes) minus the second maximum balancing time of 95 minutes required to balance the second C2 cells (25 minutes). Thus, the maximum balancing time for the first C1 cells is 121 minutes + 25 minutes, or 146 minutes.

[0060] The estimation step 106d also includes a step of determining 106d3 a maximum balancing time of the second C2 cells performed equal to the second maximum balancing time of 95 minutes.

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

[0062] Thus, as illustrated in [Fig.5], for the slave microcontroller 3b the balancing time performed 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 106d estimation step further includes a step of determining 106d5 for each second cell C2, a balancing time performed equal to the minimum value between the second balancing time of the second cell C2 to be performed and the maximum balancing time of the second cells C2 performed.

[0064] Thus, as illustrated in [Fig.5], for the slave microcontroller 31, 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 downtime of the master microcontroller 4 is less than the maximum overall balancing time of 290 minutes, the step of estimating 106d, for each first and second cells Cl, C2 supervised by the slave microcontroller 32, a balancing time performed includes the step of determining 106di a first balancing time allocated to the first cells Cl equal to the downtime of the master microcontroller 4 divided by two, the decimal of which is rounded up to the next integer, and a second balancing time allocated to the second cells C2 equal to the downtime of the master microcontroller 4 divided by two, the decimal of which is considered to be zero, in other words, whose decimal is equal to zero.

[0066] Since the first balancing time allocated to the first C1 cells (121 minutes) is greater than the first maximum balancing time of 115 minutes, and the second balancing time allocated to the second C2 cells (120 minutes) is less than the second maximum balancing time of 175 minutes, the estimation step 106d includes a step of determining 106d6, a maximum balancing time for the first C1 cells. This maximum balancing time for the first C1 cells is equal to the first maximum balancing time, i.e., 115 minutes.

[0067] The estimation step 106d includes a step of determining 106d7 a maximum balancing time of the second cells C2 performed.

[0068] This maximum balancing time for the second C2 cells is equal to the second balancing time allocated to the second C2 cells of 120 minutes plus a first unused remainder of the first balancing time allocated to the first Cl cells of 121 minutes. The first remainder is equal to the first balancing time allocated to the first Cl cells of 121 minutes. from which we subtract the first maximum balancing time of 115 minutes required to balance the first Cl cells, i.e., 6 minutes. Thus, the maximum balancing time of the second C2 cells is equal to 120 minutes + 6 minutes, or 126 minutes.

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

[0070] Thus, as illustrated in [Fig.5], for the slave microcontroller 32, the balancing time performed 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 106d estimation step further includes a step of determining 106d5 for each second cell C2, a balancing time performed equal to the minimum value between the second balancing time of the second cell C2 to be performed and the maximum balancing time of the second cells C2 performed.

[0072] Thus, as illustrated in [Fig.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 downtime of the master microcontroller 4 of 241 minutes is less than the maximum overall balancing time of 350 minutes, the step of estimating 106d for each first and second cells Cl, C2 supervised by the slave microcontroller 34 a balancing time carried out during the downtime of the master microcontroller 4 includes the step of determining 106di a first balancing time allocated to the first cells Cl equal to the downtime of the master microcontroller 4 divided by two whose decimal is rounded up to the next integer and a second balancing time allocated to the second cells C2 equal to the downtime of the master microcontroller 4 divided by two whose decimal is considered to be zero, in other words whose decimal is equal to zero.

[0074] Since the first balancing time allocated to the first Cl cells of 121 minutes is less than the first maximum balancing time of 175 minutes and the second balancing time allocated to the second C2 cells of 120 minutes is less than the second maximum balancing time of 175 minutes, the estimation step 106d includes a step of determining 106d8 a maximum balancing time of the first Cl cells carried out.

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

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

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

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

[0079] Thus, as illustrated in [Fig.5], for the slave microcontroller 34, the balancing time performed 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 106d estimation step further includes a step of determining 106d5 for each second cell C2, a balancing time performed equal to the minimum value between the second balancing time of the second cell C2 to be performed and the maximum balancing time of the second cells C2 performed.

[0081] Thus, as illustrated in [Fig.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 downtime of the master microcontroller 4 is less than the maximum overall balancing time, 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 time. The remaining balancing time is a function of: • For each first cell Cl, the balancing time performed by said first cell Cl and the first balancing time to be performed by said first cell Cl; • For each second cell C2, the balancing time performed by said second cell C2 and the second balancing time of said second cell C2 to be performed.

[0083] The method 100 further includes a step of transmitting 108, to the slave microcontrollers 3i, 32, 34, a balancing request updated according to the estimated remaining balancing times.

Claims

Demands

1. A method (100) for estimating the progress of voltage balancing performed across cells (Cl, C2) of a battery (2) in an electric or hybrid vehicle (1), the cells (Cl, C2) being arranged in an alternation of first and second cells (Cl, C2), said vehicle (1) comprising a plurality of slave microcontrollers (3b 32, 33, 34), each slave microcontroller (3b 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 time of said first cell (Cl) to be performed, and • For each second cell (C2) supervised by said slave microcontroller (3i, 32, 33, 34), a second balancing time of said second cell (C2) to be performed; -balancing is performed alternately on each first cell Cl, then on each second cell C2 according to a predetermined period, • Record (104) a moment of shutdown of said master microcontroller (4) and the first and second balancing times to be performed by each slave microcontroller (3b 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, determine (106) a progress state of the balancing performed by each slave microcontroller (3i, 32, 33, 34), said progress state being a function of the first and second balancing durations to be performed recorded, and a shutdown time of the master microcontroller (4) function of said extinction instant and of a wake-up instant of said master microcontroller (4), • transmit (108), to the slave microcontrollers, an updated balancing request based on the estimated remaining balancing times.

2. A method (100) according to the preceding claim, characterized in that the step of determining (106) a progress state of the performed balancing comprises the steps, for each slave microcontroller (3i, 32, 33, 34), of: - Select (106a), from among the first cells (Cl), a first maximum balancing time and, from among the second cells (C2), a second maximum balancing time; - Determine (106b) a maximum overall balancing time equal to the sum of said first maximum balancing time with said second maximum balancing time selected; - If the downtime of the master microcontroller (4) is greater than the maximum global balancing time, determine (106c) the completion of the balancing performed by the slave microcontroller (3b 32, 33, 34).

3. A method (100) according to any one of claims 1 or 2, characterized in that the step of determining (106) a progress state of the performed balancing comprises the steps, for each slave microcontroller (3b 32, 33, 34), of: - Select (106a), from among the first cells (Cl), a first maximum balancing time and, from among the second cells (C2), a second maximum balancing time; - Determine (106b) a maximum overall balancing time equal to the sum of said first maximum balancing time with said second maximum balancing time selected; - If the downtime of the master microcontroller (4) is less than the maximum global balancing time, estimate (106d) for each first cell (Cl) and each

4. second cell (C2), a balancing time performed 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 (C1) and each second cell (C2), a balancing time performed during the shutdown of the master microcontroller (4) comprises the steps of: - Determine (106di) a first balancing time allocated to the first cells (Cl) equal to the shutdown time of the master microcontroller (4) divided by two, whose possible decimal is rounded up to the next integer, and a second balancing time allocated to the second cells (C2) equal to the shutdown time of the master microcontroller (4) divided by two, whose possible decimal 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 time of the first cells (Cl) performed equal to the first balancing time allocated to the first cells (Cl); • Determine (106d9) a maximum balancing time for the second cells (C2) performed equal to the second balancing time allocated to the second cells (C2); • Determine (106d4) for each first cell (Cl), a balancing time performed equal to the minimum value between the first balancing time of said first cell (Cl) to be performed and the maximum balancing time of the first cells (Cl) performed: • Determine (106d5) for each second cell (C2), a balancing time performed equal to the minimum value between the second balancing time of said second cell (C2) and

5. perform and the maximum balancing time of the second cells (C2) performed. 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 time performed during the shutdown of the master microcontroller (4) comprises the steps of: - Determine (106di) a first balancing time allocated to the first cells (Cl) equal to the shutdown time of the master microcontroller (4) divided by two, whose possible decimal is rounded up to the next integer, and a second balancing time allocated to the second cells (C2) equal to the shutdown time of the master microcontroller (4) divided by two, whose possible decimal 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 greater than the second maximum balancing time, • Determine (106d2) a maximum balancing time of the first cells (Cl) performed equal to the first balancing time allocated to the first cells (Cl) plus a second remainder of the second balancing time allocated to the second cells (C2) not used, said second remainder being equal to the second balancing time allocated to the second cells (C2) minus the second maximum balancing time; • Determine (106d3) a maximum balancing time of the second cells (C2) performed equal to the second maximum balancing time; • Determine (106d4) for each first cell (Cl), a balancing time performed equal to the minimum value between the first balancing time of said first cell (Cl) and

6. to perform and the maximum equilibration time of the first cells (Cl) performed: • Determine (106d5) 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 second cells (C2) performed. 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 time performed during the shutdown of the master microcontroller (4) comprises the steps of: - Determine (106di) a first balancing time allocated to the first cells (Cl) equal to the shutdown time of the master microcontroller (4) divided by two, with any decimal rounded up to the nearest integer, and a second balancing time allocated to the second cells (C2) equal to the shutdown time of the master microcontroller (4) divided by two, with any decimal rounded up to the nearest integer; - 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 time of the first cells (Cl) performed equal to the first maximum balancing time; • Determine (106d7) a maximum balancing time for the second cells (C2) performed, equal to the second balancing time allocated to the second cells (C2) plus a first unused remainder from the first balancing time allocated to the first cells (C1), said first remainder being equal to the first balancing time allocated to the first cells (Cl) from which we subtract the first maximum equilibration time; Determine (106d4), for each first cell (Cl), a balancing time performed equal to the minimum value between the first balancing time of said first cell (Cl) to be performed and the maximum balancing time of the first cells (Cl) performed. Determine (106d5) 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 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 (3i, 32, 33, 34), the steps of: Estimate (107) for each first cell (C1) and each second cell (C2), a remaining balancing time, said remaining balancing time being a function of: For each first cell (Cl), the balancing time performed by said first cell (Cl) during the shutdown of the master microcontroller (4) and the first balancing time of said first cell (Cl) to be performed; For each second cell (C2), the balancing time performed by said second cell (C2) during the shutdown of the master microcontroller (4) and the second balancing time 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 claims previous, characterized in that, prior to the step of switching off (105) the master microcontroller (4), the method (100) includes a step of transmitting (103) to at least one slave microcontroller (3i, 32, 33, 34), a voltage balancing request (RB R2, R3, R4) across the first and second cells (Cl, C2) supervised by said at least one slave microcontroller (3i, 32, 33, 34), said balancing request (Rb R2, R3, R4) comprising, - For each first cell (Cl) supervised by said at least one slave microcontroller (3i, 32, 33, 34), a first balancing time of said first cell (Cl) to be performed, and - For each second cell (C2) supervised by said at least one slave microcontroller (3b 32, 33, 34), a second balancing time of said second cell (C2) to be performed.

9. Master microcontroller (4) of a vehicle (1), characterized in that it is arranged to perform the steps of the process (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 (3b 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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