Method of detecting the reaching of a full state of charge of a high- voltage battery of an electric vehicle at the end of a charging phase

Abstract

A method (10) of detecting the reaching of a full-charge state of a high-voltage battery of an electric vehicle at the end of a charging phase is described. A charging current (IBa tt) input to the high-voltage battery is sensed via one or more vehicle sensors. The sensed charging current (IBa tt) is compared (102) to at least one threshold current value (I BattZeroFlow_Lo ), and a first verification signal (HV_Bat_MinCrnt) is asserted if the sensed charging current (IBatt) is less than or equal to the threshold current value (l BattZeroFlow_Lo ). A maximum voltage ( VCell _Max) amongst a plurality of cells of the high-voltage battery is sensed via one or more vehicle sensors. The sensed maximum voltage (V Cell_Max ) is compared (104) to at least one threshold voltage value (ΔV BattCellMax_Hi ), and a second verification signal (HV_Bat_MaxVitg) is asserted if the sensed maximum voltage (V Cell_Max ) is greater than or equal to the threshold voltage value (ΔV BattCellMax_H ). A third verification signal (HV Bat FullChrg), indicative of the full-charge state of the high-voltage battery having been reached, is asserted in response to said first verification signal ( HV_Bat_MinCrnt) and said second verification signal ( HV_Bat_MaxVltg) being both asserted.

Description

[0001] “Method of detecting the reaching of a full state of charge of a high- voltage battery of an electric vehicle at the end of a charging phase”

[0002] ****

[0003] TEXT OF THE DESCRIPTION

[0004] Field of the invention

[0005] The present invention relates to electric vehicles equipped with a high-voltage battery, for example an 800 V battery, which primarily supplies energy to the electric powertrain (hence also referred to as traction battery), and which can be charged by connecting to an external charging infrastructure (so-called charging stations). Such vehicles may include battery electric vehicles (BEV) or hybrid electric vehicles (HEV).

[0006] The invention was developed with reference to the detection of the full charge condition of the traction battery at the end of a charging phase.

[0007] Prior art

[0008] In modem electric vehicles, which feature a high-voltage battery (e.g., 800 V - also referred to as “HV battery” in the present description) primarily dedicated to powering the powertrain and other significant electrical loads (e.g., cabin climate control system, battery pack heating / cooling system, etc.), a battery management unit (called BMS, Battery Management System) executes, during charging phases via connection to the external charging infrastructure, an algorithm to determine the state of charge of the battery (specifically, to determine its progressive increase during charging) and detect when a full charge state is reached, that is, the moment when battery charging can be considered complete. It will be understood that the completion of battery charging does not necessarily coincide with the interruption of energy transfer (i.e., current flow) from the charging station to the vehicle, as such transfer could continue, for example, to allow thermal conditioning of the cabin or the battery itself, without the need of drawing energy from the battery itself (i.e., consuming “in real time” the energy drawn from the charging station).

[0009] Some algorithms implemented by the BMS unit during the charging phase to compute the state of charge (SOC) of the battery are known. According to a known algorithm called “Coulomb counter”, the BMS unit constantly monitors the charging current during the charging phase and integrates its value over time to determine the total stored charge. Additionally, the BMS unit measures the battery voltage under static conditions, after a prolonged settling time, without affecting the current flow to the battery. The measurement system for the battery input current has a certain tolerance, which may lead to incorrect or imprecise estimation of the state of charge of the battery during charging. For example, an underestimate of the battery charging current results in an underestimate of the state of charge during charging. Moreover, the input charging current to the battery is limited (not by the BMS unit, but by other safety systems) to prevent exceeding a certain maximum limit of the battery voltage which, under static conditions, corresponds to the full charge condition of the traction battery. Therefore, if the BMS unit makes an error by underestimating the state of charge of the traction battery while the driver requests a full charge of the traction battery (i.e. , charging up to 100% SOC), a situation may arise where, as charging nears completion, the input charging current to the battery is strongly limited (ideally to zero) for safety reasons since the maximum allowed voltage for the traction battery (or for the individual cells composing the traction battery) has already been reached, but the BMS unit does not detect the end of the charging phase because the state of charge (SOC) is underestimated and not yet considered by the BMS unit to be 100%. This can create a deadlock situation where charging is actually interrupted (as it has actually been completed) but the vehicle remains in the “charging in progress” state for an extended period, during which the driver waits without observing any appreciable charging progress.

[0010] Document US 2022 / 0089054 A1 exemplifies the prior art and describes a method for estimating the time for a full charging of the battery packs of an electric vehicle. The method includes: (i) determining a predetermined transition voltage based on a charging capacity of a charger; (ii) estimating a voltage of a battery pack; (iii) determining a constant charging-current phase duration, a transition from the constant chargingcurrent phase to a tapered charging-current phase occurring when the estimated voltage equals the predetermined transition voltage, the constant charging-current phase duration being based on the transition to the tapered charging-current phase; (iv) determining a tapered charging-current phase duration; and (v) adding the constant charging-current phase duration to the tapered charging-current phase duration to determine a charging time.

[0011] Document US 7974796 B2 also exemplifies the prior art and describes a method for detecting the capacity of a fully-charged battery. First and second no-load voltages of the battery are detected at first no-load timing and second no-load timing, respectively. Further, first and second remaining capacities of the battery are determined based on the first and second no-load voltages, respectively, when the first no-load voltage falls within a predetermined voltage range. Moreover, a fully-charged battery capacity is calculated based on a remaining capacity variation rate and a capacity variation value of the battery. Also, the variation rate of the remaining capacity is calculated based on a difference between the first and second remaining capacities. The capacity variation value of the battery is calculated based on an integrated value of the charging current and discharge currents of the battery to be charged / discharged from the first no- load to the second no-load timing.

[0012] Therefore, there is a need in the art to develop a method of determining the state of charge of a high-voltage battery of an electric vehicle, in particular to detect the reaching of a full-charge state (e.g., 100%) at the end of the charging phase, to avoid the aforementioned deadlock situation where the battery is actually fully charged but the BMS unit does not detect such a condition, forcing the driver of the vehicle to wait unnecessarily until the BMS unit detects that charging has actually been completed.

[0013] Object of the invention

[0014] The object of the invention is to solve the aforementioned technical problem. In particular, the object of the invention is to provide a method of detecting the reaching of the full-charge state (e.g., 100%) of a high-voltage battery of an electric vehicle at the end of a charging phase, to avoid the aforementioned deadlock situation where the battery is actually fully charged but the BMS unit does not detect such a condition.

[0015] It should be noted that the terminology “full-charge state” used here indicates a state of charge equal to 100% or sufficiently close to 100% (within a few hundredths or tenths of a percentage point, e.g., 99.95% or 99.90%) as to make negligible the advantage related to any further increase in state of charge that could still be obtained if the vehicle remained connected to the charging station (i.e., passing from 99.95% or 99.90% to 100%), but causing a significant prolongation of the driver’s waiting time, as the charging current is extremely limited under such SOC conditions.

[0016] Summary of the invention

[0017] The object of the invention is achieved by a method having the features forming the subject of the claims that follow, which constitute an integral part of the technical teaching provided herein in relation to the invention.

[0018] The method may be implemented by one or more electronic control units of a vehicle, for example external to the control unit of the battery management system (BMS).

[0019] Brief description of the figures

[0020] The invention will now be described with reference to the accompanying figures, provided by way of non-limiting example, wherein:

[0021] - Figure 1 is a block diagram illustrating the phases of a method for detecting the reaching of the full-charge state of a high-voltage battery of an electric vehicle, according to one or more embodiments of the present description;

[0022] - Figure 2 is a block diagram illustrating some steps of the method according to one or more embodiments of the present description, in particular for verifying whether the input charging current to the battery is null;

[0023] - Figure 3 is a block diagram illustrating some steps of the method according to one or more embodiments of the present description, in particular for verifying whether the maximum voltage across the battery cells equals a nominal threshold value corresponding to the full-charge state;

[0024] - Figure 4 is a block diagram illustrating some steps of the method according to one or more embodiments of the present description, in particular for declaring the full-charge state based on the occurrence of certain conditions regarding charging current, battery cell voltage, and an indication provided by the BMS unit of the vehicle;

[0025] - Figure 5 is a diagram exemplifying the qualitative temporal trend of input and output signals of a delay block (or debouncer) used in the scheme illustrated in Figure 4;

[0026] - Figure 6 is a diagram exemplifying the qualitative temporal trend of signals and / or physical quantities of interest in the method according to one or more embodiments of the present description; and

[0027] - Figure 7 is a block diagram summarizing the phases of a method for detecting the reaching of the full-charge state of the high-voltage battery of an electric vehicle, according to one or more embodiments of the present description.

[0028] Detailed description

[0029] As mentioned earlier, the invention is applicable to electric vehicles equipped with a high-voltage battery that can be charged via an external charging infrastructure (charging station), and relates to a method for detecting the reaching of the full-charge state of the high-voltage battery at the end of the charging phase. According to one or more embodiments, detection of the full-charge state is carried out by detecting the simultaneous occurrence of two conditions over a certain safety time interval, namely that the input current flow to the battery is zero or nearly zero, and that the voltage across the battery cells equals or is sufficiently close to the nominal voltage value corresponding to the full-charge condition.

[0030] As shown in the block diagram of Figure 1 , the method 10 may comprise substantially three phases indicated by references 102, 104 and 106. In phase 102, further described in the following, it is determined, by sensing (e.g., measuring via one or more vehicle sensors) the current iBatt input to the high-voltage battery, whether such current is less than or equal to a certain threshold value, such that the charging current can be considered substantially zero. If so, a signal (or flag) HV_Bat_MinCrnt is asserted, otherwise signal HV_Bat_MinCrnt is de-asserted. In phase 104, further described in the following, it is determined, based on the voltage Vceii_Max (which is the maximum voltage measured across all battery cells of the high-voltage battery) and a limit value Vceiijviaxjjm of the cell voltage (provided by an external algorithm), whether the voltage measured across the battery cells is greater than or equal to a certain threshold value, such that the voltage of the traction battery can be considered substantially equal to the nominal value corresponding to the full-charge condition. If so, a signal (or flag) HV_Bat_MaxVltg is asserted, otherwise signal HV_Bat_MaxVltg is de-asserted. In phase 106, further described in the following, it is determined whether the full-charge state of the traction battery has been reached based on the binary signals HV_Bat_MinCrnt and HV_Bat_MaxVltg determined (i.e., asserted or de-asserted) in phases 102 and 104 respectively, and based on the full-charge signal BMSpuiichrg produced by the BMS unit of the vehicle. If full charge is determined, a signal (or flag) HV_Bat_FullChrg is asserted, otherwise signal HV_Bat_FullChrg is de-asserted.

[0031] Operation of block 102 for determining whether the input current to the battery is zero or nearly zero will now be described with reference to Figure 2. In particular, the assertion and de-assertion of signal HV_Bat_MinCrnt to respectively indicate whether the current IBatt input to the battery is zero or not can be implemented with hysteresis. As exemplified in Figure 2, the measured value IBatt of the input current to the traction battery of the vehicle is passed to a calculation block 21 that computes its absolute value lBatt_Abs. The signal HV_Bat_MinCrnt is produced at the output of a set-reset (SR) flip-flop 22. Substantially, flip-flop 22 is set (by asserting the signal at the set input S of the flip-flop, produced by a comparator 23) when the (e.g., measured) absolute value lBatt_Abs of the charging current of the high-voltage battery is less than or equal to a certain lower threshold lBattzeroFiow_Lo (e.g., equal to 2 A), and is reset (by asserting the signal at the reset input R of the flip-flop, produced by a comparator 24) when the absolute value lBatt_Abs of the charging current of the high-voltage battery is greater than or equal to a certain upper threshold I BattzeroFiow_Hi (e.g., equal to 4 A). Thus, substantially, comparators 23 and 24 together with the set-reset flip-flop 22 collectively behave as a hysteresis comparator, which asserts signal HV_Bat_MinCrnt when the absolute value lBatt_Abs of the current decreases reaching a value equal to or below the lower threshold lBattzeroFiow_Lo and de-asserts signal HV_Bat_MinCrnt when the absolute value lBatt_Abs of the charging current increases reaching a value equal to or above the upper threshold lBattzeroFiow_Hi. The lower threshold I BattzeroFiow_Lo and the upper threshold lBattzeroFiow_Hi can be stored in a vehicle control unit, and thus represent two internal constants for the method according to the present invention. The use of two thresholds lBattzeroFiow_Lo and I Battzero Fiow_Hi prevents instability effects (toggling) of signal HV_Bat_MinCrnt. From a physical standpoint, the assertion of signal HV_Bat_MinCrnt substantially indicates that the current flowing in the traction battery is practically zero or negligible in terms of its influence on voltage, and thus the battery is electrically balanced. It should be noted, however, that the absolute value operation performed in block 21 is optional in cases where the measured current Isatt is conventionally positive. Calculating the absolute value of the current iBatt advantageously allows to verify the existence of steady-state conditions from both charging and discharging perspectives.

[0032] Operation of block 104 for determining whether the voltage of the traction battery equals the value corresponding to full-charge condition will now be described with reference to Figure 3. In particular, the assertion and de-assertion of signal HV_Bat_MaxVltg to respectively indicate whether the battery voltage is indicative of full-charge or not can be implemented with hysteresis. As exemplified in Figure 3, the value Vceiijviaxjjm of the voltage limit for each individual cell of the traction battery (which is provided by an external vehicle algorithm, and thus represents an input parameter for the method according to the present invention) is subtracted from the measured value Vceii_Max, which is the highest among all voltages measured across all battery cells of the high-voltage battery, in a subtractor calculation block 31 to produce a differential voltage value (or margin) A Vceiijviax. Signal HV_Bat_MaxVltg is produced at the output of a set-reset (SR) flip-flop 32. Substantially, flip-flop 32 is set (by asserting the signal at the set input S of the flip-flop, produced by a comparator 33) when the differential voltage value A Vceiijviax is greater than or equal to a certain upper threshold A VBattceiiMax_Hi (e.g., equal to 0 V), and is reset (by asserting the signal at the reset input R of the flip-flop, produced by a comparator 34) when the differential voltage value A Vceiijviax is less than or equal to a certain lower threshold A VBattceiiMaxj.o (e.g., equal to -0.02 V). Thus, substantially, comparators 33 and 34 together with the set-reset flip-flop 32 collectively behave as a hysteresis comparator, which asserts signal HV_Bat_MaxVltg when the differential voltage value AVceiijviax increases reaching a value equal to or above the upper threshold AVBattceiiMax_Hi and de-asserts signal HV_Bat_MaxVltg when the differential voltage value AVceiijviax decreases reaching a value equal to or below the lower threshold AVBattceiiMax o. The lower threshold A VBattceiiMax_Lo and the upper threshold A VBattceiiMax_Hi can be stored in a vehicle control unit, and thus represent two internal constants for the method according to the present invention. The use of two thresholds Z\ VBattceiiMax_Lo and AVBattceiiMax_Hi prevents instability effects (toggling) of signal HV_Bat_MaxVltg. It should be noted, however, that the subtraction operation carried out in block 31 is optional, as the same behavior of operation block 104 could be obtained by appropriately remodulating the values of the two thresholds AVBattceiiMax o and AVBattceiiMaxjn (e.g., using absolute voltage values as thresholds instead of voltage deltas, and directly comparing the voltage Vceiijviax to two thresholds having values equal to

[0033] VBattCellMax_Lo+Vcell_Ma im).

[0034] Operation of block 106 to determine whether the full-charge state has been reached (and thus whether it is possible to declare the end of the vehicle charging phase) based on signals HV_Bat_MinCmt and HV_Bat_MaxVltg and on the full-charge signal BMSpuiichrg produced by the BMS unit of the vehicle will now be described with reference to Figures 4 and 5. As exemplified in Figure 4, the binary signals HV_Bat_MinCrnt and HV_Bat_MaxVltg are processed by a logic gate 41 to produce an additional binary signal HV_Bat_FullChrglntRaw which is asserted when both input signals HV_Bat_MinCrnt and HV_Bat_MaxVltg are asserted (e.g., an AND logic gate). In this way, signal (or flag) HV_Bat_FullChrglntRaw is asserted when current flow to the battery is zero or very close to zero, and simultaneously the maximum voltage across the cells of the traction battery is reached. From a physical standpoint, the assertion of signal HV_Bat_FullChrglntRaw substantially indicates that the traction battery is electrically balanced in full-charge condition, and thus no further charging current can flow into the battery, or any current flow would be negligible in terms of energy increase compared to the extended waiting time. Signal HV_Bat_FullChrglntRaw is then processed in a delay block 42 to produce a “filtered” signal HV_Bat_FullChrglnt. The delay block 42 operates as exemplified in the diagram of Figure 5, which shows the temporal trends of a generic input signal ILIDL and a generic output signal OutDL of a generic delay block DL, and a generic delay with duration AtDeiay. Substantially, the delay block DL delays only the rising edges of its input signal IFIDL by an amount equal to time interval AtDeiay, while the falling edges of input signal IriDL are propagated substantially without delay. As a consequence, any assertions of the input signal IFIDL with total duration shorter than interval AtDeiay are completely filtered by the delay block DL (see for example instants to, ti and t2 in Figure 5), while assertions of input signal ILIDL with total duration longer than interval AtDeiay are initially filtered (i.e., output signal OutDL remains low for a period equal to AtDeiay) and then propagated (see for example instants ts, t4 and ts in Figure 5). In other words, delay block DL performs a sort of “debouncing” of the input signal ILIDL with a filtering time equal to AtDeiay. Therefore, returning to Figure 4, signal HV_Bat_FullChrglntRaw is processed in delay block 42 which operates as discussed in relation to Figure 5 using a filtering time equal to AtHv_Bat_Fuiichrg (e.g., equal to 20 minutes) to produce a filtered output signal HV_Bat_FullChrglnt. The filtering time AtHv_Bat_Fuiichrg may be stored in a vehicle control unit, and thus represents an internal constant for the method according to the present invention. From a physical standpoint, filtering signal HV_Bat_FullChrglntRaw through delay block 42 to produce signal HV_Bat_FullChrglnt indicates that it is preferable to wait for a certain settling time when both conditions (i) zero charging current and (ii) maximum battery cell voltage occur before “declaring” that the full-charge condition of the traction battery has been reached (i.e., before asserting signal HV_Bat_FullChrglnt). As exemplified in Figure 4, the binary signal HV_Bat_FullChrglnt produced based on steps 102 and 104 of the method, and the binary signal BMSFuiichrg asserted by the BMS unit of the vehicle to indicate that charging is complete, are processed by a logic gate 43 to produce an output binary signal (or flag) HV_Bat_FullChrg which is asserted when at least one of the input signals HV_Bat_FullChrglnt and BMSFuiichrg is asserted (e.g., an OR logic gate). In this way, the output signal (or flag) HV_Bat_FullChrg is asserted when at least one of the method described here and the “conventional” algorithm executed by the BMS unit decrees that charging has been completed.

[0035] The method described here can be further understood by referring to Figure 6, which is a timing diagram including qualitative waveforms of signals Vceiijviax, HV_Bat_MaxVltg, I Batt, HV_Bat_MinCrnt, HV_Bat_FullChrglntRaw and HV_Bat_FullChrglnt. During the battery charging phase, voltage Vceiijviax across the battery cells increases (see up to instant to) and input current IBatt to the battery normally decreases gradually, since as state of charge (SOC) increases, the receivable input current usually decreases for physical and safety reasons. At instant to, the maximum voltage Vceiijviax across the battery cells reaches the limit value Vcell_Max_Lim, Condition Vceii viax - Vcell_Max_Lim — t^ Vcell_Max — t^ VBattCellMax_Hi occurs, resulting in assertion of signal HV_Bat_MaxVltg. At instant ti, the input current IBatt to the battery approaches zero, condition IBatt \BattzemFiow_Lo occurs, resulting in assertion of signal HV_Bat_MinCrnt. The fact that both signals HV_Bat_MaxVltg and HV_Bat_MinCrnt are asserted causes assertion of signal HV_Bat_FullChrglntRaw at instant ti, which in turn causes assertion of signal HV_Bat_FullChrglnt after time interval AtHv_Bat_Fuiichrg has elapsed, at instant t2. Assertion of signal HV_Bat_FullChrglnt indicates that battery charging is complete and thus the charging phase of the electric vehicle can be terminated.

[0036] Therefore, as can be understood from the preceding description, the method 10 described herein for detecting the reaching of the full-charge state of the high-voltage battery substantially comprises three phases, as also exemplified in the block diagram of Figure 7:

[0037] - in phase 102, it is detected whether the input current to the battery has reached a minimum value equal to zero or nearly zero, based on the absolute value of the measured input current to the battery;

[0038] - in phase 104, it is detected whether the maximum voltage across the battery cells has reached a maximum value equal to the nominal value corresponding to the full-charge condition, based on the maximum voltage of the battery cells and the maximum voltage limit of the battery cells; and

[0039] - in phase 106, it is determined that the battery charge is complete (and thus the charging phase is terminated) if both the condition on the input current to the battery and the condition on the maximum voltage of the battery cells are simultaneously satisfied for a certain time interval, or if the full-charge condition is determined by the BMS unit of the vehicle.

[0040] The method for detecting the reaching of the full-charge state of the

Claims

battery described herein thus avoids “deadlock” conditions, with consequent prolonged waiting for the driver, which may occur when detection of the fullcharge state is solely entrusted to the BMS unit of the vehicle.Of course, implementation details and embodiments may vary widely from what has been described and illustrated without thereby departing from the scope of the invention as defined by the appended claims.CLAIMS1. A method (10) of detecting the reaching of a full-charge state of a high-voltage battery of an electric vehicle at the end of a charging phase, said method (10) comprising:- sensing, via one or more sensors of said vehicle, a charging current (iBatt) input to the high-voltage battery;- comparing (102) said sensed charging current (IBatt) to at least one threshold current value (lBattzeroFiow_Lo), and asserting a first verification signal (HV_Bat_MinCrnt) in response to said sensed charging current (IBatt) being less than or equal to said at least one threshold current value ( / BattZeroFlowJ-o)',- sensing, via one or more sensors of said vehicle, a maximum voltage ( Vceiijviax) amongst a plurality of cells of said high-voltage battery;- comparing (104) said sensed maximum voltage ( Vceiijviax) to at least one threshold voltage value (AVBattceiiiviaxjii), and asserting a second verification signal (HV_Bat_MaxVltg) in response to said sensed maximum voltage ( Vceiijviax) being greater than or equal to said at least one threshold voltage value (AVBattceiiiviaxjii)- asserting a third verification signal (HV_Bat_FullChrg), indicative of the full-charge state of the high-voltage battery having been reached, in response to said first verification signal (HV_Bat_MinCrnt) and said second verification signal (HV_Bat_MaxVltg) being both asserted.

2. The method (10) of claim 1 , wherein the step of comparing (102) said sensed charging current (IBatt) to at least one threshold current value (lBattzeroFiowj-o) comprises computing (21) an absolute value (lBatt_Abs) of said sensed charging current (IBatt), and comparing said current absolute value (lBatt_Abs) to said at least one threshold current value (lBattzeroFiow_Lo).

3. The method (10) of claim 1 or claim 2, wherein the step of comparing (102) said sensed charging current with at least one threshold current value comprises comparing said sensed charging current (IBatt, lBatt_Abs) to a lower threshold current value (23, iBattzeroFiow o) and to an upper threshold current value (24, lBattzeroFiowj-n), asserting (22) said first verification signal (HV_Bat_MinCrnt) in response to said sensed charging current (IBatt, lBatt_Abs) being less than or equal to said lower threshold currentvalue (23, lBattzeroFiowj.o), and de-asserting (22) said first verification signal (HV_Bat_MinCrnt) in response to said sensed charging current (Isatt, lBatt_Abs) being greater than or equal to said upper threshold current value (24, I BattZeroFlowJ-li) .

4. The method (10) of any of the previous claims, wherein the step of comparing (104) said sensed maximum voltage ( Vceiijviax) to at least one threshold voltage value (Z\ VBattceiiMax_Hi) comprises subtracting (31) a voltage limit value ( Vceiijviax jjm) of the single battery cell from said sensed maximum voltage ( Vceiijviax) to produce a difference voltage value (AVceiijviax), and comparing said difference voltage value (Z\ Vceiijviax) to said at least one threshold voltage value (AVBattceiiMaxjii).

5. The method (10) of any of the previous claims, wherein the step of comparing (104) said sensed maximum voltage to at least one threshold voltage value comprises comparing said sensed maximum voltage ( Vceiijviax, AVceiijviax) to an upper threshold voltage value (33, VBattceiiMaxj-n) and to a lower threshold voltage value (34, AVBattceiiiviaxj.o), asserting (32) said second verification signal (HV_Bat_MaxVltg) in response to said sensed maximum voltage ( Vceiijviax, AVceiijviax) being greater than or equal to said upper threshold voltage value (33, AVBattceiiMax_Hi), and de-asserting (32) said second verification signal (HV_Bat_MaxVltg) in response to said sensed maximum voltage ( Vceiijviax, AVceiijviax) being less than or equal to said lower threshold voltage value (34, AVBattCellMaxJ-o).

6. The method (10) of any of the previous claims, wherein assertion of said third verification signal (HV_Bat_FullChrg) is carried out with a certain delay (AtHv_Bat_Fuiichrg) relative to the instant when said first verification signal (HV_Bat_MinCrnt) and said second verification signal (HV_Bat_MaxVltg) are both asserted.

7. The method (10) of any of the previous claims, comprising asserting said third verification signal (HV_Bat_FullChrg) in response to a fourth verification signal (BMSFuiichrg) being asserted, said fourth verification signal (BMSFuiichrg) being produced by a high-voltage battery management system.

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