Method for determining and resetting the state of charge of a battery in a hybrid vehicle - Patents.com

Abstract

The invention relates to a method for determining and resetting the state of charge of at least one battery of a hybrid vehicle comprising a first battery, a second battery and a heat engine, the method comprising a first step of charging the first battery with the second battery during a vehicle standby phase, during which (i) the first battery is charged, (ii) a value V1mes of the voltage of the first battery is measured, (iii) V1mes is compared with a threshold voltage value V1seuilmax corresponding to a maximum state of charge SOC1max of the first battery, (iv) if V1mes reaches said threshold voltage value V1seuilmax, stopping charging the first battery, determining that the first battery is in a maximum state of charge SOC1max and setting the value SOC1 of the state of charge of the first battery to SOC1max, and otherwise continuing charging.

Description

Summary of the Invention

[0001] The present invention provides a method for determining the state of charge of a battery in a hybrid vehicle and for recharging the battery. Compare It's about how to fix it.

[0002] In the non-limiting field of electric and hybrid vehicles, one of the main challenges for systems managing traction batteries is estimating the battery's state of charge (SoC). This information is displayed on the dashboard in the form of a "battery gauge" and allows the driver to know the remaining driving range. Because the driving range of electric vehicles is less than that of internal combustion engine vehicles, it is important to provide the driver with the most reliable information possible for their reassurance. Errors in estimating the battery gauge can lead to the driver finding themselves in an uncomfortable situation (running out of fuel / charge) or even a dangerous situation (lack of power while overtaking).

[0003] Currently, the state of charge of a battery may be determined either by measuring the voltage or via coulometry, i.e., by measuring the ampere-hours (Ah) going into or out of the battery.

[0004] Furthermore, future restrictions on recycling will result in the elimination of heavy metals from vehicles and the replacement of current lead-acid batteries with lithium-ion batteries, and especially lithium-iron-phosphate batteries (LFP batteries).

[0005] Currently, lithium-ion batteries, and LFP batteries in particular, have curves of open-circuit voltage as a function of state of charge that incorporate one or more plateaus of the type shown in Figure 1. Accurate determination of the state of charge is then virtually impossible by measuring voltage at levels accompanied by these plateaus, i.e., when the state of charge is between 40% and 70% and between 75% and 95% for the battery in question in the example of Figure 1.

[0006] Coulometry, a method based on the integration of current, inherently assumes drift, an error in the measurement of current, for some of which accumulates over time. This method therefore requires periodic recalibration via voltage measurements. Compare For batteries whose curve of voltage as a function of state of charge is of the type shown in Figure 1, it is then necessary to nearly fully recharge or discharge the battery so that voltage measurements can be made in a region of the curve where the state of charge can be accurately determined. This may be achieved in a variety of ways depending on the type of vehicle.

[0007] Thus, when the vehicle is an all-electric vehicle or a "plug-in hybrid", i.e., a vehicle that can be recharged via the main power grid, the two batteries of the vehicle (traction battery and auxiliary battery) may be recharged simultaneously and Compare Positive charging may be performed when charging is nearly complete.

[0008] In hybrid vehicles (with an internal combustion engine, traction battery and auxiliary battery) or "mild hybrid" vehicles (where the battery may be recharged during driving by recovering kinetic energy from braking), the battery is recharged via the internal combustion engine while the vehicle is being driven. Compare The charge is then carried out while driving. CompareDuring this corrective phase, however, it is not possible to recover the kinetic energy of braking, which prevents optimal management of the vehicle's energy. In particular, when both batteries are LFP batteries, it is possible for the auxiliary battery to be in a state of charge such that it may be gauged by measuring the voltage. In contrast, to ensure optimal energy management, the traction battery must be installed in a plateau region where voltage-based gauging is not possible because this is insufficiently accurate. Only coulometric methods remain for determining the state of charge, with the attendant risk of drift. These risks of drift can be avoided by periodically recharging the traction battery by bringing it to a sufficiently high state of charge to allow accurate gauging by measuring the voltage. Compare Correcting this will now be compensated. Compare The braking is then performed while driving, which complicates hybrid energy management, affects the vehicle's movement, and reduces braking kinetic energy to the extent that it is not used. Compare Increases the CO2 footprint at positive points.

[0009] Therefore, it is possible to accurately determine the state of charge and to recharge the traction battery and auxiliary battery without interfering or only slightly interfering with the vehicle's energy management during driving. Compare There is a need for a method that allows correction.

[0010] The document WO201937012A1 describes a device for determining the state of charge of a battery when the vehicle is in standby / restart mode. CompareThis paper discloses a method for correcting the battery voltage. The method involves measuring the battery voltage at two separate time intervals while the vehicle is stopped and in standby, and then using a correlation between the two voltage measurements with the battery's open circuit voltage (OCV) as a parameter. The OCV is then determined by a recursive least squares algorithm. The state of charge is then determined as a function of the OCV, for example, via mapping or the like. This method for determining the state of charge therefore uses relatively complex calculations and may not always be reliable depending on the type of chemistry.

[0011] The present invention aims to remedy all or part of the above-mentioned drawbacks.

[0012] To this end, a method is provided for determining the state of charge of at least one battery of a hybrid vehicle and for recharging the battery. Compare The hybrid vehicle includes a first battery, a second battery, and an internal combustion engine, and the method includes a first step of charging the first battery using the second battery during a vehicle standby phase, the first step including: (i) a first battery is charged, particularly at time t1; (ii) a value V1mes of the voltage of the first battery is measured; (iii) comparing the measured voltage value V1mes with a threshold voltage value V1threshmax corresponding to a maximum state of charge SOC1max of the first battery; (iv) If the measured voltage value V1mes reaches the threshold voltage value V1threshmax, charging the first battery is stopped, it is determined that the first battery is in a maximum state of charge SOC1max, and the state of charge value SOC1 of the first battery is set to the maximum state of charge value SOC1max; otherwise, charging the first battery continues.

[0013] Therefore, at the end of the standby, CompareIt is possible to restart the vehicle with at least one gauge of the corrected battery. This restart can be done outside of the vehicle driving phase. Compare By implementing this, it is possible to optimize the energy management of the vehicle during the driving phase in a particularly simple manner.

[0014] However, in the standby phase, it is possible that the state of charge of the second battery is insufficient to allow the first battery to be charged to its maximum state of charge in the first charging step. Therefore, advantageously, during the first charging step: - in step (ii), the value of the voltage of the second battery, V2mes, is measured; - in step (iii), the value of the measured voltage V2mes is compared with a threshold voltage value V2threshmin corresponding to a minimum state of charge SOC2min of the second battery; - in step (iv), if the value V2mes of the measured voltage of the second battery reaches the threshold voltage value V2threshmin, it is determined that the second battery has reached the minimum state of charge SOC2min, charging the first battery is stopped and the state of charge value SOC2 of the second battery is set to the minimum state of charge value SOC2min, otherwise charging the first battery continues.

[0015] By monitoring the state of charge of the second battery in this manner, it is not discharged beyond its capacity, which allows the life of the battery to be maintained and extended.

[0016] Once the first charging step is completed, the second battery may then be charged, either because the first battery has reached a maximum state of charge, or because the second battery has reached a minimum state of charge.

[0017] The method may therefore advantageously comprise, during the same vehicle standby phase and after the first charging step, a second step of charging the second battery using the first battery, during which: (i) The second battery is charged.

[0018] The second battery may then be charged until the vehicle driving phase and / or until the second battery reaches a maximum or optimum state of charge as determined by monitoring the voltage measured across its terminals.

[0019] Thus, in one embodiment, in the second charging step: (ii) a value V2mes of the voltage of the second battery is measured; (iii) comparing the measured voltage value V2mes with a threshold voltage value V2threshmax corresponding to a maximum state of charge SOC2max of the second battery; (iv) If the measured voltage value V2mes reaches the threshold voltage value V2threshmax, charging of the second battery is stopped, the second battery is determined to be in a maximum state of charge SOC2max, and the state of charge value SOC2 of the second battery is set to the maximum state of charge value SOC2max; otherwise, charging of the second battery continues.

[0020] This embodiment is suitable for recharging the gauge of the second battery during the standby phase. Compare The gauge of the first battery recharges itself during the first charging step. Compare This is particularly advantageous when the second battery is fully charged, i.e., when the first battery is being recharged, to allow the first battery to reach its maximum state of charge. Although not preferred, this embodiment also allows the second battery, which nevertheless reached its minimum state of charge in the first charging step, to be recharged when the gauge of the first battery is recharged. Compare It may also be considered in cases where it prevents correction.

[0021] In this embodiment, the method may advantageously include a third step of charging the first battery with the second battery during the same vehicle standby phase and after the second charging step, the third step comprising: (i) the first battery is charged; (ii) measuring the voltage values ​​V1mes, V2mes of at least one of the two batteries; (iii) comparing each measured voltage value V1mes, V2mes with an optimal voltage value V1opt, V2opt corresponding to a state of charge of the battery that is optimal for that vehicle driving phase; (iv) If at least one of the measured voltage values ​​V1mes, V2mes reaches the corresponding optimal voltage value, charging of the first battery is stopped; otherwise, charging continues.

[0022] This third step allows the vehicle to be restarted in the next driving phase under conditions that are optimal for charging at least one of the two batteries, which will generally be chosen to place the second battery (typically the auxiliary battery) in an optimal state of charge.

[0023] In another embodiment, in the second charging step of the method according to the invention: (ii) measuring the voltage values ​​V1mes, V2mes of at least one of the two batteries; (iii) comparing each measured voltage value V1mes, V2mes with an optimal voltage value V1opt, V2opt corresponding to a state of charge of the battery that is optimal for that vehicle driving phase; (iv) If at least one of the measured voltage values ​​V1mes, V2mes reaches the corresponding optimal voltage value, charging of the second battery is stopped; otherwise, charging continues.

[0024] In this embodiment, in the first charging step, the gauge of the first battery is CompareThis is particularly advantageous in cases where a minimum state of charge has been reached that would prevent the first battery from being corrected (premature termination of the first charging step). Specifically, this makes it possible to avoid over-discharging the first battery while simply being satisfied that at least one of the batteries has reached a state of charge that is optimal for the driving phase. Generally, this will be chosen to place the second battery (typically the auxiliary battery) in an optimal state of charge. This embodiment is also advantageous in cases where the gauge of the first battery has recharged itself during the first charging step, although this is not preferred. Compare It is also possible to imagine cases where this has been corrected.

[0025] Advantageously, the method according to the invention may comprise a step of balancing the constituent cells of the battery charged during the first or second charging step during the same vehicle standby phase and in particular immediately after the first or second charging step in which the value of the measured voltage of the battery being charged reaches a threshold voltage value corresponding to a state of maximum charge, in which case the subsequent charging step is carried out at the end of this balancing step.

[0026] In cases where a battery fails to reach maximum charge in the first or second charging step, either because the second battery is not sufficiently charged and reaches minimum charge (for the first battery) first, or because the standby phase ends before the first or second battery reaches maximum charge, provision may advantageously be made to charge this battery in the operating phase.

[0027] Advantageously, therefore, the method according to the invention comprises, in a vehicle driving phase immediately following said standby phase: comparing a current state-of-charge value of at least one of the plurality of batteries, or even each of the batteries, with a predetermined threshold value; and - when a value of a current state of charge of the battery is less than a threshold value, commencing a step of charging the battery using an internal combustion engine of the vehicle, wherein the charging step includes: (i) charging the battery; and optionally (ii) a value of the open circuit voltage of the battery is determined; (iii) comparing the determined open circuit voltage value to a threshold voltage value corresponding to a maximum state of charge of the battery; (iv) If the determined open circuit voltage value reaches the threshold voltage value, charging of the battery is stopped, the battery is determined to be at a maximum state of charge, and the state of charge value of the battery is set to the maximum state of charge value; otherwise, charging of the battery continues.

[0028] When the current state of charge value of the respective battery or at least one of the batteries is equal to or greater than this threshold value, no charging action is initiated during driving, and the vehicle's energy management system may then be optimized.

[0029] Advantageously, the method according to the invention may give priority to the traction battery when the vehicle is started in order to ensure that the state of charge of the traction battery is always sufficient to ensure traction of the vehicle.

[0030] Therefore, advantageously, in the method according to the invention, the first battery is a traction battery and the second battery is an auxiliary battery of the vehicle. Typically, the nominal voltage of the traction battery (average voltage during the discharge phase) is higher than the nominal voltage of the auxiliary battery.

[0031] The invention also a first battery, in particular a traction battery, a second battery, in particular an auxiliary battery, and an internal combustion engine intended for a hybrid vehicle; - Battery management devices and Also relates to a system comprising: a battery management device for determining the state of charge of at least one of said batteries using the method according to the invention, and Compare It is configured to correct.

[0032] Finally, the invention relates to a hybrid vehicle equipped with such a system.

[0033] The invention will now be described with reference to the accompanying non-limiting drawings. [Brief explanation of the drawings]

[0034]

Figure 1

Figure 2

Figure 3

[0035] Hybrid vehicles typically: - The traction battery, also known as the high-voltage battery, ensures the vehicle's traction. A traction battery generally has a nominal voltage of 48V. - An auxiliary battery, also known as a low-voltage battery, is used to power electrical and electronic devices on board a vehicle. An auxiliary battery is generally a battery with a nominal voltage of 12V. - The internal combustion engine, which also ensures the vehicle's traction. Equipped with.

[0036] In the method according to the invention, each of the traction battery and the auxiliary battery may be recharged either by the other battery in the standby phase or by the internal combustion engine in the driving phase.

[0037] To this end, the battery and the internal combustion engine are connected to a battery management device configured to carry out the method according to the invention. This management device typically comprises one or more processors (e.g., microprocessors, microcontrollers, etc.) programmed in particular to carry out the method according to the invention. The management device may also comprise means for communication with the battery, optionally means for bidirectional communication, and voltage measurement means. The one or more processors may comprise storage means, which may be random access memory (RAM), electrically erasable programmable read-only memory (EEPROM), flash memory, external memory, etc. These storage means may store, among other things, received data, a control model, one or more maps, and one or more computer programs. The management device may, for example, form part of or form a battery management system (BMS) of the vehicle.

[0038] 2 and 3, BATT1 denotes the traction battery and BATT2 denotes the auxiliary battery of the hybrid vehicle, the solid curve represents the state of charge SOCi indicated by the gauge of battery i, and the dashed curve represents the actual state of charge SOCri of battery i.

[0039] FIG. 2 illustrates one embodiment of the method according to the invention, in which the gauges of two batteries are recharged. Compare In this diagram, phase PR1 is the vehicle driving phase, during which the traction battery BATT1 undergoes continuous charging and discharging, the charging corresponding to, for example, recovering kinetic energy from braking, and the discharging corresponding to vehicle traction. The state of charge of the auxiliary battery BATT2 does not change or changes very little.

[0040] PK is a standby phase that follows the driving phase PR1. This standby phase PK may be detected by the management device in a conventional manner based on parameters representative of the state of the vehicle (torque, etc.) received from appropriate sensors. According to the invention, this standby phase PK is used to charge multiple batteries one after the other so that they reach a state of maximum charge, whose state of charge can be accurately determined for any type of battery based on the measured voltage.

[0041] In this example, when the standby phase PK is detected, the management device triggers a first charging step (denoted E1) at time t1, in which (i) the traction battery is charged using the auxiliary battery. Since the auxiliary battery is now fully charged, this first charging step E1 continues until the traction battery reaches a maximum state of charge at time t1+Δt. To this end, the following steps will be repeated: (ii) a voltage value V1mes across the terminals of the traction battery is measured, (iii) the measured voltage value V1mes is compared with a threshold voltage value V1threshmax corresponding to a maximum state of charge SOC1max of the traction battery, and (iv) if the measured voltage value V1mes reaches this threshold voltage value V1threshmax, charging of the traction battery is stopped, the traction battery is determined to be in a maximum state of charge SOC1max, and the state of charge value SOC1 of the traction battery is set to the maximum state of charge value SOC1max; otherwise, charging of the traction battery continues.

[0042] A person skilled in the art will be able to determine the repetition frequency depending on the type of battery. The value V1mes of the voltage measured across the terminals of the battery corresponds here to the open circuit voltage and the vehicle is in standby phase. The threshold voltage value V1threshmax and the corresponding state of maximum charge SOC1max may be determined by a person skilled in the art depending on the type of battery on the basis of a curve of the type shown in Figure 1. The threshold voltage value V1threshmax and the value SOC1max of maximum charge may be recorded in the management device, for example in the form of a map or a curve of the type shown in Figure 1.

[0043] At the end of the first charging step E1 (at time t1+Δt), the traction battery is thus fully recharged and its gauge recharges. Compare It is then advantageously possible to rebalance the constituent cells of the traction battery in a balancing step EQ1. Such rebalancing is well known to those skilled in the art and will not be described in great detail. This is typically performed by suitable electronic components connected to the cells of the battery.

[0044] After this optional balancing step EQ1, a second charging step E2 is performed at time t2, in which (i) the auxiliary battery is charged using the traction battery. This second charging step E2 continues until, at time t2+Δt, the auxiliary battery reaches its maximum state of charge. To this end, the procedure is similar to that followed in the first step E1, and the following steps are repeated: (ii) a voltage value V2mes across the terminals of the auxiliary battery is measured, (iii) the measured voltage value V2mes is compared with a threshold voltage value V2threshmax corresponding to the maximum state of charge SOC2max of the auxiliary battery, and (iv) if the measured voltage value V2mes reaches the threshold voltage value V2threshmax, charging of the auxiliary battery is stopped, the auxiliary battery is determined to be in its maximum state of charge SOC2max, and the state of charge value SOC2 of the auxiliary battery is set to the maximum state of charge value SOC2max; otherwise, charging of the auxiliary battery continues.

[0045] This second charging step is therefore exactly like the first charging step, with the threshold voltage values ​​and maximum state of charge values ​​being specific to the auxiliary battery.

[0046] At the end of this second charging step E2, it is also possible to carry out an optional step EQ2 of rebalancing the constituent cells of the auxiliary battery.

[0047] After this optional rebalancing step EQ2, a third step E3 of charging the traction battery using the auxiliary battery would normally be performed, in which (i) the traction battery is charged, (ii) a voltage value V1mes, V2mes of at least one of the two batteries is measured, (iii) each measured voltage value V1mes, V2mes is compared with an optimal voltage value V1opt, V2opt corresponding to the corresponding battery's state of charge SOC1opt, SOC2opt that is optimal for the vehicle driving phase, and (iv) if at least one of the measured voltage values ​​V1mes, V2mes reaches the corresponding optimal voltage value, charging of the traction battery is stopped, otherwise charging is continued.

[0048] Thus, at the end of step E3, at time t3+Δt, at least one of the batteries, or indeed both batteries, is in a state of charge that is optimal for the next driving phase. These optimal states of charge may be determined by those skilled in the art depending on the type of batteries and the energy management of the vehicle during the driving phase. Those skilled in the art may particularly preferably select an optimal state of charge for the auxiliary battery or the traction battery, or even for both.

[0049] Determining and Recharging the Battery Compare The whole process of correcting is thus finished, and the battery management device waits for the next operating phase without triggering any other charging or discharging actions.

[0050] FIG. 3 illustrates one embodiment of the method according to the invention, in which the gauge of the traction battery is recharged. Compare In this figure, phase PR1 is a vehicle driving phase similar to that described with reference to Figure 2. PK is a standby phase following driving phase PR1, and PR2 is a driving phase following parking phase PK.

[0051] 3 illustrates the case where the auxiliary battery is not fully charged when the vehicle is put into standby to allow the traction battery to be fully recharged. The first charging step E1 is interrupted when, during monitoring of the value of the auxiliary battery voltage, the management device determines that the value of the voltage V2mes measured across the terminals of the auxiliary battery has reached a threshold voltage V2threshmin corresponding to the minimum state of charge SOC2min of the auxiliary battery. This is done in addition to steps (ii) to (iv) described above by repeatedly measuring the value of the auxiliary battery voltage V2mes and comparing the measured value V2mes with the threshold voltage value V2threshmin, respectively, and by requesting a halt to charging when this threshold value is reached. The value SOC2 of the state of charge of the auxiliary battery is then set to the minimum state of charge value SOC2min, which is the quantity used in step (iv) to prioritize the state of charge of the auxiliary battery. If the gauge of the auxiliary battery is nevertheless recharged, CompareAt the end of this first charging step, which allows the traction battery to be corrected, a second step E2 of charging the auxiliary battery with the traction battery is then advantageously performed at time t2 until at least one of the batteries reaches an optimal state of charge SOC1opt, SOC2opt. This second charging step E2 is then similar to step E3 described with reference to FIG. 2. Generally, in this second charging step E2, it is the auxiliary battery that is given priority and whose state of charge is sought to be optimized. The management device then waits for the next driving phase PR2. In this case, a step Er of charging the traction battery using the internal combustion engine of the hybrid vehicle rather than the auxiliary battery is performed at time tr, and in particular at the beginning of driving phase PR2, insofar as the traction battery is generally not in an optimal state of charge. The value of the traction battery voltage is then monitored by repeating steps (ii) to (iv) similar to those of the first step E1. It should be noted that in this case, the voltage measured across the traction battery terminals no longer corresponds to the open circuit voltage across the battery terminals. It may then be necessary to determine the open circuit voltage from the measured voltage, for example via Kalman filtering type modeling, before comparing the measured voltage with a maximum threshold voltage value. This threshold value may or may not be the same as the threshold value used in the standby phase.

[0052] This replay is performed while driving. Compare At the end of the positive step, at time tr+Δt, the management device will be able to manage the energy of the hybrid vehicle optimally in step Eg, in particular by recharging the traction battery with the kinetic energy recovered while braking the vehicle.

[0053] Therefore, in both cases (FIGS. 2 and 3), the auxiliary battery, which ensures safe operation of the vehicle, will be charged once driving begins, unless the vehicle is started in the middle of the process.

[0054] In the latter case, charging of the auxiliary battery may be initiated in order to restore it to its maximum state of charge as quickly as possible and to satisfy safety requirements with the internal combustion engine, for example, at the beginning of a driving phase. It is then possible to proceed as described for the traction battery in step Er. In this case, the traction battery recharge may also be initiated. Compare Re-gauge the traction battery even if it means making the energy management less optimal. Compare triggered to correct the

[0055] It should be noted that when one of the two batteries reaches, for example, a minimum state of charge and a maximum state of charge in two different standby phases, it is possible to determine the remaining capacity of the battery and, if appropriate, to make a prediction to perform a maintenance operation if this remaining capacity is determined to be too low, for example below a threshold value.

[0056] The method according to the invention therefore requires no complex calculations to be performed, no accurate reading of the battery gauge being essential in the standby phase. Compare This allows for positive control without the need for a positive control, so that the vehicle's energy management is not hindered during the driving phase.

Claims

1. 1. A method for determining and recalibrating a state of charge of at least one battery of a hybrid vehicle, the hybrid vehicle comprising a first battery, a second battery, and an internal combustion engine, the method comprising a first step of charging the first battery with the second battery during a vehicle standby phase, the step comprising: (i) the first battery is charged; (ii) a value V1mes of the voltage of the first battery is measured; (iii) comparing the value V1mes of the measured voltage with a threshold voltage value V1threshmax corresponding to a maximum state of charge SOC1max of the first battery; (iv) if the value V1mes of the measured voltage reaches the threshold voltage value V1threshmax, charging the first battery is stopped, the first battery is determined to be in a maximum state of charge SOC1max, and the state of charge value SOC1 of the first battery is set to the maximum state of charge value SOC1max; otherwise, charging the first battery continues. method.

2. During the first step of charging, In step (ii), a value V2mes of the voltage of the second battery is measured; In step (iii), the value V2mes of the measured voltage is compared to a threshold voltage value V2threshmin corresponding to a minimum state of charge SOC2min of the second battery; 2. The method of claim 1, wherein, in step (iv), if the value V2mes of the measured voltage of the second battery reaches the threshold voltage value V2threshmin, it is determined that the second battery has reached a minimum state of charge SOC2min, charging the first battery is stopped, and the state of charge value SOC2 of the second battery is set to the minimum state of charge value SOC2min; otherwise, charging the first battery continues.

3. a second step of charging the second battery using the first battery during the same vehicle standby phase and after the first charging step, wherein during the second step: (i) the second battery is charged; The method according to claim 1 or 2.

4. In the second step of charging, (ii) a value V2mes of the voltage of the second battery is measured; (iii) comparing the value V2mes of the measured voltage with a threshold voltage value V2threshmax corresponding to a maximum state of charge SOC2max of the second battery; (iv) if the value V2mes of the measured voltage reaches the threshold voltage value V2threshmax, charging the second battery is stopped, the second battery is determined to be in a maximum state of charge SOC2max, and the state of charge value SOC2 of the second battery is set to the maximum state of charge value SOC2max; otherwise, charging the second battery continues. The method of claim 3.

5. a third step of charging the first battery using the second battery during the same vehicle standby phase and after the second charging step, wherein the third step comprises: (i) the first battery is charged; (ii) measuring the voltage values ​​V1mes, V2mes of at least one of the two batteries; (iii) comparing each of the measured voltage values ​​V1mes, V2mes with an optimal voltage value V1opt, V2opt corresponding to a state of charge of the battery that is optimal for that vehicle driving phase; (iv) if at least one of the measured voltage values ​​V1mes, V2mes reaches the corresponding optimal voltage value, stopping charging the first battery; otherwise, continuing charging; The method of claim 4.

6. In the second step of charging, (ii) measuring the voltage values ​​V1mes, V2mes of at least one of the two batteries; (iii) comparing each measured voltage value V1mes, V2mes to an optimal voltage value V1opt, V2opt corresponding to a state of charge of the battery that is optimal for that vehicle driving phase; (iv) if at least one of the measured voltage values ​​V1mes, V2mes reaches the corresponding optimal voltage value, charging of the second battery is stopped; otherwise, charging continues; The method of claim 3.

7. 3. The method of claim 1, further comprising the step of balancing constituent cells of the battery being charged during the first or second charging step during the same vehicle standby phase and immediately after the first or second charging step.

8. a vehicle driving phase immediately following the vehicle standby phase, comparing a current state of charge value of at least one battery to a predetermined threshold value; When the current state of charge value of a battery is less than the threshold value, commencing the step of charging the battery using the internal combustion engine of the hybrid vehicle, wherein the charging step includes: (i) charging the battery; and optionally: (ii) an open circuit voltage value of the battery is determined; (iii) comparing the determined open circuit voltage value to a threshold voltage value corresponding to a maximum state of charge of the battery; (iv) if the determined open circuit voltage value reaches the threshold voltage value, charging the battery is stopped, the battery is determined to be in a maximum state of charge, and the state of charge value of the battery is set to the maximum state of charge value; otherwise, charging the battery continues. The method according to claim 1 or 2.

9. 3. The method of claim 1 or 2, wherein the first battery is a traction battery and the second battery is an auxiliary battery of the hybrid vehicle.

10. a first battery, a second battery, and an internal combustion engine for a hybrid vehicle; Battery management device and A system comprising: The battery management device is configured to determine and recalibrate the state of charge of at least one of the batteries using the method of claim 1 or 2. system.

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