CELLULAR BATTERY RECHARGE MANAGEMENT IN A SYSTEM BASED ON CELL CHEMISTRY

Abstract

A method is used to manage the charging of a cellular battery comprising electrochemical cells, each with an estimated cell state of charge, a measured cell temperature, and a measured cell voltage, and equipping a system. This method includes a step (10-70) in which, when the cellular battery is requested to be recharged, at least one maximum charging current is determined as a function of either the measured cell temperatures and measured cell voltages when the electrochemical cells have an open-circuit voltage versus state of charge curve without a plateau region, or the measured cell temperatures and estimated cell states of charge when the electrochemical cells have an open-circuit voltage versus state of charge curve with at least one plateau region. Figure 3

Description

Title of the invention: MANAGEMENT OF CELLULAR BATTERY RECHARGES IN A SYSTEM BASED ON CELL CHEMISTRY Technical field of the invention

[0001] The invention relates to cellular batteries, and more specifically to the management of the recharging of such cellular batteries. State of the art

[0002] In many fields, such as for example that of vehicles (possibly of the automotive type), cellular batteries are used in which the cells are electrochemical and can have different chemistries.

[0003] During a cell battery charging phase, the associated control unit is responsible for monitoring the charging process to ensure it is safe and uses the most stable charging current possible, thereby guaranteeing the cell battery's performance for a predefined period. Currently, the battery control unit determines successive maximum charging currents based on measured cell temperatures and voltages, and decides to terminate charging when the total state of charge (SOC) of the cell battery equals the total state of charge desired by the system user. The desired total state of charge is considered to have been reached when a corresponding maximum cell voltage is attained.

[0004] Now, as those skilled in the art know, the cellular batteries described above have a curve showing the evolution of their open-circuit voltage as a function of their total state of charge, which does not exhibit a plateau zone or at least exhibits a plateau zone (at least from about 5%). Here, a "plateau zone" is understood to mean a zone in which a small variation in the open-circuit voltage (typically less than 10 mV) corresponds to a large variation in the state of charge (typically greater than 15%).Thus, Lithium Iron Phosphate (or LFP) electrochemical cell batteries have a voltage evolution curve as a function of their state of charge which has at least a plateau zone (and therefore increases very slowly), whereas electrochemical cell batteries of the so-called "mixed metal oxide" type (for example NCM (Nickel Cobalt Manganese) or NCA (Nickel Cobalt Aluminium)) have a voltage evolution curve as a function of their state of charge which does not have a plateau zone (and therefore increases rapidly).

[0005] Due to these variations in the evolution of the total open-circuit voltage as a function of Due to the chemistry of electrochemical cells, the control of charging is insufficiently adapted to electrochemical cell batteries whose open-circuit voltage curve versus state of charge exhibits at least one plateau zone. It is understandable that it is particularly difficult to determine whether a desired maximum cell voltage actually corresponds to the desired total state of charge when the total state of charge can vary significantly without this being observable in the evolution of the maximum cell voltage. Consequently, during a full charge, the user is frequently made to wait longer than necessary (when it is difficult to determine if the maximum state of charge has been reached).

[0006] In addition, the problem described above is increased by the fact that the state of charge is a parameter which is estimated, and therefore it may be subject to deviations from reality which may result in a final undercharge penalizing in terms of autonomy or a final overload potentially dangerous because it may lead to internal damage and / or heating likely to trigger a fire in the event of thermal runaway.

[0007] The invention therefore aims in particular to improve the situation. Presentation of the invention

[0008] In particular, it proposes for this purpose a management method intended to enable the management of recharging of a cellular battery comprising electrochemical cells each having an estimated cellular state of charge, a measured cellular temperature and a measured cellular voltage, and suitable for equipping a system.

[0009] This management method is characterized by the fact that it includes a step in which, in the event of a demand for recharging the cellular battery, at least one maximum recharging current is determined as a function of either the measured cellular temperatures and measured cellular voltages when the electrochemical cells have a curve of evolution of an open-circuit voltage as a function of their state of charge not exhibiting a plateau area, or the measured cellular temperatures and estimated cellular states of charge when the electrochemical cells have a curve of evolution of an open-circuit voltage as a function of their state of charge exhibiting at least a plateau area.

[0010] Thanks to this management of recharging based on the chemistry of electrochemical cells, it is possible to reduce the duration of complete recharging when the electrochemical cells have a curve of evolution of their open-circuit voltage as a function of their state of charge which has at least one plateau area, while reducing the risk of overcharging the cell battery.

[0011] The management method according to the invention may include other features which can be taken separately or in combination, and in particular:

[0012] - in its stage, in the presence of electrochemical cells having a curve evolution of an open-circuit voltage as a function of their state of charge not exhibiting a plateau zone, each maximum charging current can be determined as a function of the smallest and largest cell temperatures measured among all the cell temperatures measured and the largest cell voltage measured among all the cell voltages measured;

[0013] - in the presence of the first option, in its step, one can determine in a The first lookup table establishes a correspondence between charging current values ​​and pairs of cell temperature and cell voltage. On the one hand, a first charging current value corresponds to the lowest measured cell temperature and highest measured cell voltage, and on the other hand, a second charging current value corresponds to the highest measured cell temperature and highest measured cell voltage. Then, the maximum charging current can be determined by taking the smaller of these first and second charging current values.

[0014] - in its stage, in the presence of electrochemical cells having a curve based on the evolution of their open-circuit voltage as a function of their state of charge which has at least one plateau area, we can determine each maximum charging current as a function of the smallest and largest cell temperatures measured among all the cell temperatures measured and the largest estimated cell state of charge among all the estimated cell states of charge;

[0015] - in the presence of the last option, in its step, one can determine in a The second lookup table establishes a correspondence between charging current values ​​and pairs of cell temperature and cell charge state. On the one hand, there is a third charging current value corresponding to the lowest measured cell temperature and the highest estimated cell charge state, and on the other hand, a fourth charging current value corresponding to the highest measured cell temperature and the highest estimated cell charge state. Then, the maximum charging current can be determined by taking the smallest of these third and fourth charging current values.

[0016] - in its step, the ongoing charging can be stopped when a voltage at the terminals of the cellular battery is equal to a voltage value which is chosen according to a desired total state of charge, and that the maximum charging current has become less than a limit value for charge controllability;

[0017] - in the presence of the last option, in its step, when a recharge request If partial state of charge is required, a corrected total state of charge can be used, which is determined from an estimated total state of charge of the cellular battery and a margin. of total charge state inaccuracy.

[0018] The invention also proposes a computer program product comprising a set of instructions which, when executed by processing means, is suitable for implementing a management method of the type presented above for managing the recharging of a cellular battery comprising electrochemical cells each having an estimated cell charge state, a measured cell temperature and a measured cell voltage, and suitable for equipping a system.

[0019] The invention also proposes a management device for managing the recharging of a cellular battery comprising electrochemical cells, each having an estimated cellular state of charge, a measured cellular temperature and a measured cellular voltage, and suitable for equipping a system.

[0020] This management device is characterized in that it includes at least one processor and at least one memory arranged to perform the operations consisting, in the event of a request to recharge the cellular battery, of determining at least one maximum charging current as a function of either the measured cellular temperatures and measured cellular voltages when the electrochemical cells have a curve of evolution of an open-circuit voltage as a function of their state of charge not exhibiting a plateau area, or the measured cellular temperatures and estimated cellular states of charge when the electrochemical cells have a curve of evolution of an open-circuit voltage as a function of their state of charge exhibiting at least one plateau area.

[0021] The invention also proposes a system comprising, on the one hand, a cellular battery comprising electrochemical cells each having an estimated cellular state of charge, a measured cellular temperature and a measured cellular voltage, and, on the other hand, a management device of the type presented above. Brief description of the figures

[0022] Other features and advantages of the invention will become apparent from an examination of the detailed description below, and the accompanying drawings, in which:

[0023] [Fig-1] schematically and functionally illustrates an example of the realization of a vehicle comprising a management device according to the invention and a powertrain with an electric drive unit powered by a cellular battery associated with a battery computer,

[0024] [Fig.2] schematically and functionally illustrates an example of the realization of a battery calculator comprising a management device according to the invention, and

[0025] [Fig.3] schematically illustrates an example of an algorithm implementing an management method according to the invention. Detailed description of the invention

[0026] The invention aims in particular to provide a management method, and a device associated DG management, intended to enable the management in an S system of the recharging of a BC cellular battery according to the chemistry of the electrochemical cells CE of the latter (BC).

[0027] In what follows, system S is considered, by way of non-limiting example, to be a motor vehicle, such as a car, as illustrated in [Fig. 1]. However, the invention is not limited to this type of system. It relates to any type of system comprising at least one cellular battery (rechargeable, for example, by an external power source temporarily connected to the system). Thus, it relates to vehicles (land, sea (or river), and air), mobile machinery (including those performing a lifting function), electronic devices (possibly household appliances and / or possibly mobile), installations (possibly industrial), and buildings, for example.

[0028] Furthermore, in what follows, by way of non-limiting example, the vehicle S is considered to comprise an all-electric powertrain (or PMT) (and therefore comprising at least one electric drive unit associated with a cellular battery). However, the PMT could be of the hybrid type (and in this case, the vehicle S is powered by at least one internal combustion engine and one electric drive unit).

[0029] A system S (here a vehicle) comprising an all-electric GMP transmission chain (and therefore comprising at least one electric drive machine MME), a CS supervisory computer, a BS auxiliary battery, a BC cellular battery, a CV converter, and a DG management device according to the invention is schematically represented in [Fig.1].

[0030] The auxiliary battery BS is responsible for supplying electrical power to the vehicle's on-board electrical system RB, supplementing that supplied by the CV converter, which is powered by the cell battery BC via a main electrical circuit, and sometimes replacing this CV converter. For example, this auxiliary battery BS may be configured as a very low voltage type battery (typically 12 V, 24 V, or 48 V). It is rechargeable at least by the CV converter. In the following, for the sake of non-limiting example, the auxiliary battery BS is considered to be a 12 V lithium-ion type.

[0031] The RB on-board network is an electrical power supply network to which electrical (or electronic) equipment (or components) that consume electrical energy are coupled.

[0032] The main electrical circuit (or "high voltage" or "power" circuit) is connected, on the one hand, to the cellular battery BC via an interface device, and, on the other hand, to electronic equipment, such as the CV converter and the MME drive machine. It also allows the cellular battery BC to be recharged by a external SA power source temporarily coupled to vehicle S for example via a CR charging cable temporarily connected to a CN charging connector of vehicle S.

[0033] The transmission system has a powertrain which, in this case, is purely electric, and therefore includes, in particular, in addition to its (electric) drive machine, a drive shaft and a transmission shaft. The term "electric drive machine" here refers to an electric machine arranged to provide torque to move the system S (here, a vehicle), and possibly to recover regenerative braking torque. The operation of the powertrain is supervised by a control unit.

[0034] The drive unit MME (here an electric motor) is connected to the cell battery BC via the main electrical circuit, in order to be supplied with electrical energy, and also possibly to supply this cell battery BC with electrical energy during a regenerative braking phase. It is connected to the motor shaft, to provide it with torque by rotational drive. This motor shaft is connected to a reduction gear RD which is also connected to the transmission shaft, itself connected to a first set of wheels Tl, preferably via a differential DF.

[0035] This first train Tl is here located in the front part PVV of the vehicle S. But in a variant this first train Tl could be the one which is here referenced T2 and which is located in the rear part PRV of the vehicle S.

[0036] The operation of the drive machine MME is controlled by a machine computer CM, and supervised by the supervisory computer CS.

[0037] The CV converter is also responsible, here, during the driving phases of vehicle S, for converting a portion of the electrical current stored in the cellular battery BC to supply converted electrical current to the vehicle's electrical system RB and the auxiliary battery BS (for recharging it). It is also, here, electrically coupled, via the main electrical circuit, to the charging connector CN of vehicle S, which, during a charging phase of the cellular battery BC, is intended to be temporarily connected to an external power source SA, via a charging cable CR.

[0038] It will be noted, as illustrated non-limitingly in [Fig.1], that the CV converter can be part of an internal CH charger also comprising a CA computer responsible, at least, for controlling the charging of the cellular battery BC.

[0039] The BC cellular battery comprises at least one electrochemical cell CE, and preferably several, having a curve of evolution of its open-circuit voltage uvc as a function of its state of charge ecc having at least one plateau zone or having no plateau zone.

[0040] It is recalled that the term "plateau zone" here means a zone in which a Small variation in cellular open-circuit voltage uvc (typically less than 10 mV) corresponds to a large variation in cellular charge state ecc (typically greater than 15%).

[0041] For example, each CE electrochemical cell can be of the lithium-ion (or Li-ion) type. Also, for example, the BC cell battery can be of the low-voltage type (typically 450 V by way of illustration). But it could also be of the medium-voltage or high-voltage type.

[0042] It should be noted, as illustrated in Figure 1, that when the BC cellular battery comprises several electrochemical cells, these cells can be part of MC modules that are coupled together, for example in series. Here, an "MC module" is understood to mean a group of at least one electrochemical cell. When an MC module comprises several electrochemical cells, these cells (EC) can be coupled together in series and / or in parallel.

[0043] It should be noted that the BC cell battery is associated with a BB battery housing which includes, in particular, means for measuring total voltage ut, cell voltage uc, current and cell temperature te (not shown), and a CB battery calculator. This CB battery calculator centralizes the current measurements, voltage measurements and cell temperature measurements (in particular those relating individually to each of the N electrochemical cells CE), and estimates parameters of the BC cell battery based on these measurements, including its internal resistance, minimum voltage, charge, total state of charge (or SOC) ect and maximum state of charge ecm, and the cell state of charge ecc (of each electrochemical cell CE). It should be noted that the maximum state of charge ecm varies over time, and in particular depending on the aging of the BC cell battery and the temperature of the air surrounding it (BC).

[0044] It should also be noted that in the example illustrated, but not limited to, in [Fig. 1], the vehicle S also includes a distribution box BD to which the auxiliary battery BS, the CV converter, and the on-board network RB are coupled. This distribution box BD is responsible for distributing into the on-board network RB the electrical energy produced by the CV converter or stored in the auxiliary battery BS, to power the electrical components (or equipment) coupled to the on-board network RB, according to power demands received (in particular from the powertrain control unit CS).

[0045] As mentioned above, the invention proposes in particular a management method intended to allow the management in the system S (here a vehicle) of the recharging of its cellular battery BC according to the chemistry of the electrochemical cells CE of the latter (BC).

[0046] This (management) process can be implemented at least partially by the The DG management device (illustrated in [Fig. 2]) comprises at least one PR1 processor, for example, a digital signal processor (DSP), and at least one MD memory. This DG management device can therefore be implemented as a combination of electrical or electronic circuits or components (or "hardware") and software modules (or "software"). For example, it could be a microcontroller.

[0047] The MD memory is random access memory (RAM) to store instructions for the implementation by the PR1 processor of at least part of the management process. The PR1 processor may comprise integrated (or printed) circuits, or several integrated (or printed) circuits connected by wired or wireless connections. An integrated (or printed) circuit is defined as any type of device capable of performing at least one electrical or electronic operation.

[0048] In the example illustrated, but not limited to, in Figures 1 and 2, the DG management device is part of the CB battery computer. However, it could be part of another computer embedded in the S system (such as, for example, the CA computer of the CH internal charger), or it could comprise its own dedicated computer.

[0049] As illustrated non-limitingly in [Fig.2], the (management) method according to the invention includes a step 10-70 which is implemented each time a user of the system S wants to recharge the cellular battery BC (and therefore, here, once the charging connector CN has been temporarily coupled to a power source SA external to the vehicle S, via a charging cable CR).

[0050] Step 10-70 of the process includes a substep 10 in which one (for example the management device DG) receives from the user of the system S a request to recharge the cellular battery BC which defines a desired state of charge ecd.

[0051] Step 10-70 of the process also includes a substep 40 or 60 in which at least one maximum recharge current irmax is determined (for example, by the DG management device), which is a function of:

[0052] - i.e., measured cell temperatures te and measured cell voltages uc when the electrochemical cells CE have a curve of evolution of their open-circuit voltage uvc as a function of their state of charge ecc not exhibiting a plateau zone,

[0053] - i.e., measured cell temperatures te and cell states of charge estimated ecc when the electrochemical CE cells have a curve of evolution of their open-circuit voltage uvc as a function of their state of charge ecc exhibiting at least a plateau zone.

[0054] It is also recalled that once a maximum charging current irmax has been determined (based on the chemistry of the electrochemical cells CE), the use of a charging current ir that is less than or equal to this maximum charging current is imposed by the power supply SA (for example, the management device DG). irmax.

[0055] It should also be noted that several maximum charging currents irmax can be successively determined so that the total state of charge ect can become equal to the desired state of charge ecd.

[0056] Thanks to these considerations of estimated cell charge states (ECC) or measured cell voltages (UC), depending on whether the electrochemical cells (EC) have a voltage curve (UVC) representing the evolution of their open-circuit voltage (ECC) as a function of their charge state (ECC) that exhibits at least one plateau zone or does not exhibit a plateau zone, it is now possible to precisely control all charging cycles regardless of the chemistry of the electrochemical cells (EC). Consequently, the invention makes it possible to reduce the duration of complete charging cycles when the electrochemical cells (EC) have a voltage curve (UVC) representing their open-circuit voltage (ECC) representing at least one plateau zone, while also reducing the risk of overcharging the cell battery (BC).

[0057] It should be noted that when CE electrochemical cells are of Lithium-ion technology and have a curve showing the evolution of their open-circuit voltage (uvc) as a function of their state of charge (ecc) which exhibits at least one plateau region, they may be of the Lithium Iron Phosphate (or LFP) type, for example. It should also be noted that when CE electrochemical cells are of Lithium-ion technology and have a curve showing the evolution of their open-circuit voltage (uvc) as a function of their state of charge (ecc) which does not exhibit a plateau region, they may, for example, be of the mixed metal oxide type (e.g., NCM (Nickel Cobalt Manganese) or NCA (Nickel Cobalt Aluminum)). However, the invention is not limited to CE electrochemical cells of Lithium-ion technology.

[0058] For example, and as illustrated, but not limited to, in [Fig. 3], step 10-70 of the process may include a substep 20 in which the chemistry of the electrochemical cells (ECs) can be determined (for example, by the control device DG), and more specifically whether the latter (ECs) have a curve showing the evolution of their open-circuit voltage uvc as a function of their state of charge ecc that exhibits at least one plateau zone or does not exhibit a plateau zone. In this case, if the electrochemical cells (ECs) have a curve showing the evolution of their open-circuit voltage uvc as a function of their state of charge ecc that does not exhibit a plateau zone, step 10-70 of the process may include at least substep 40 described below. On the other hand, if the electrochemical cells CE have a curve of evolution of their open-circuit voltage uvc as a function of their state of charge ecc which has at least a plateau zone, step 10-70 of the process may include at least substep 60 described later.

[0059] Also, for example, when dealing with electrochemical cells CE having a curve of evolution of their open-circuit voltage uvc as a function of their state of Since the ECC charge does not have a plateau zone, step 10-70 can, as illustrated non-limitingly in [Fig. 3], include substep 40 in which one (for example, the DG management device) can determine each maximum charging current irmax as a function of the smallest tcmin and largest tcmax cell temperatures measured among all the measured cell temperatures te and the largest measured cell voltage ucmax among all the measured cell voltages uc.

[0060] In this case, step 10-70 can, as illustrated non-limitingly in [Fig. 3], include a substep 30 in which one (for example, the DG management device) can begin by determining, in a first lookup table, establishing a correspondence between charging current values ​​ir and pairs of cell temperature te and cell voltage uc, the first vl and second v2 charging current values.The first charging current value vl corresponds to the pair with the lowest measured cell temperature tcmin and the highest measured cell voltage ucmax in the first lookup table. The second charging current value v2 corresponds to the pair with the highest measured cell temperature tcmax and the highest measured cell voltage ucmax in the first lookup table. Then, in substep 40 of step 10-70, one (for example, the management device DG) can determine the maximum charging current irmax by taking the smaller of the first vl and second v2 charging current values ​​determined (i.e., irmax = min(vl; v2)).

[0061] When dealing with electrochemical cells CE having a curve of evolution of their open-circuit voltage uvc as a function of their state of charge ecc which has at least one plateau area, in substep 60 of step 10-70, one (for example the management device DG) can determine each maximum recharge current irmax as a function of the smallest tcmin and largest tcmax cell temperatures measured among all the measured cell temperatures te and the largest estimated cell state of charge eccmax among all the estimated cell states of charge ecc.

[0062] In this case, step 10-70 may, as illustrated non-limitingly in [Fig. 3], include a substep 50 in which one (for example, the management device DG) may begin by determining, in a second lookup table establishing a correspondence between recharge current values ​​ir and pairs of cell temperature te and cell state of charge ecc, the third v3 and fourth v4 recharge current values. The third recharge current value v3 corresponds to the pair having the lowest measured cell temperature tcmin and the highest estimated cell state of charge eccmax in the second lookup table. The fourth recharge current value v4 corresponds to the pair including the highest measured cell temperature tcmax and the highest estimated cell charge state eccmax in the second lookup table. Then, in substep 60 of step 10-70, one (for example the DG management device) can determine the maximum recharge current irmax by taking the smallest of the third v3 and fourth v4 recharge current values ​​determined (i.e., irmax = min(v3; v4)).

[0063] It will be noted that, regardless of the chemistry of the electrochemical cells CE, step 10-70 can, as illustrated non-limitingly in [Fig.3], include a substep 70 in which charging can be stopped (for example, the management device DG can trigger the stopping of) when the total voltage ut across the terminals of the cell battery BC is equal to a voltage value vt which is chosen according to the desired total state of charge ecd, and the maximum charging current irmax has become less than a limit value for charge controllability.

[0064] In this case, in substep 70 of step 10-70, when a partial charging request is made by the user, one (for example, the management device DG) can use a corrected total state of charge ectc which is determined from the estimated total state of charge ect and a margin of error in the total state of charge mie. Preferably, the corrected total state of charge ectc is equal to the estimated total state of charge ect less the margin of error in the total state of charge mie (i.e., ectc = ect - mie).

[0065] For example, the margin of error of the total state of charge mie can be between 1% and 5% of the estimated total state of charge ect. By way of illustration, the margin of error of the total state of charge mie can be equal to 3% of the estimated total state of charge ect. But other chosen values ​​of duration can be used. For example, the value of the margin of error of the total state of charge mie can be chosen during the development phase of the BC cell battery.

[0066] This option is designed to prevent the actual total state of charge from exceeding the estimated total state of charge, as this could lead to a maximum charging current, irmax, exceeding the capacity of the BC cellular battery at any given time. It is understood that such a situation could result in a potentially dangerous overcharge, potentially causing internal damage and / or overheating that could trigger a fire in the event of thermal runaway. This therefore increases the safety of the system S and its users, as well as the lifespan of the BC cellular battery.

[0067] It should also be noted that if the recharge request received in substep 10 indicates that the user wants to obtain a desired total state of charge ecd equal to the maximum state of charge ecm that the cellular battery BC can support at the given time, it is possible, for example, to impose (for example, the management device DG can, for example, trigger the imposition of) the use of the maximum recharge current irmax up to obtaining a maximum cellular voltage ucmax greater than or equal to a first threshold if.

[0068] It should also be noted that the first threshold si may depend on the chemistry and aging of the BC cell battery, as well as possibly on the temperature of the air surrounding it (BC). In this case, the first threshold si is determined by the DG management device based on the variable parameters of the BC cell battery. However, it could also be predefined based on the chemistry of the BC cell battery.

[0069] Next, once ucmax > si, a multi-step charge can be performed (for example, the DG management device can trigger the execution of a multi-step charge). Here, "multi-step charge" refers to a charging phase comprising a multitude of successive replacement steps prn. In each step prn, it is possible to impose (for example, the DG management device can trigger the imposition of) the use by the power supply SA of a charging current irn that is strictly lower than the previous charging current ir„ (used during the previous step prn i), until the charging current irn used during the current step pr„ (with n' > n) is less than a second threshold s2.

[0070] At least two different embodiments of the multi-step charging phase can be envisaged.

[0071] For example, in a first embodiment, when the charging current used irn is greater than the second threshold s2, the multi-step charging can be interrupted (for example, the management device DG can trigger an interruption) when the number vp of steps prn performed is equal to a maximum number of steps npmax. It will be understood that this interruption is triggered even when the last charging current used irn is still greater than the second threshold s2, because it is considered that performing at least one additional step prn+i would not significantly increase the current state of charge of the cellular battery BC.

[0072] Also, for example, the maximum number of steps npmax can be between 8 and 12. As an illustrative example, the maximum number of steps npmax can be 10. But other values ​​for the maximum number of steps npmax can be used. For example, the value of the maximum number of steps npmax can be chosen during the development phase of the BC cell battery.

[0073] Alternatively, in a second embodiment, when the charging current used irn is greater than the second threshold s2, the multi-step charging can be interrupted (for example, the management device DG can trigger an interrupt) when the latter has been carried out for a duration equal to a chosen duration. It will be understood that this interruption is decided even if the last charging current used irn is still greater than the second threshold s2, because we consider that continuing the multi-step charging phase would not significantly increase the current state of charge of the BC cellular battery.

[0074] For example, the selected duration can be between 1 and 12 hours. As an illustrative example, the selected duration can be 5 hours. However, other values ​​for the selected duration can be used. For example, the selected duration can be chosen during the BC cell battery development phase. It should be noted that this selected duration may vary depending on the type of power source SA used (fast charging or slow charging).

[0075] It should also be noted that the second threshold s2 can be a function of the minimum charging current that can be delivered by the power supply SA performing the charging. As an illustrative example, the second threshold s2 can be equal to the minimum charging current. It is clear that it is pointless to continue a multi-step charging phase by imposing the use of a new charging current ir„ lower than the minimum charging current (or controllability limit value of the charging) that can be delivered by the power supply SA, as this would not allow the current state of charge of the cellular battery BC to be increased. However, other values ​​for the second threshold s2 can be used, including a value slightly higher than the minimum charging current. For example, the value of the second threshold s2 can be chosen during the development phase of the cellular battery BC.

[0076] It will also be noted that in step 10-70, during each step prn of the multi-step charging, it is possible to impose (for example, the management device DG can trigger the imposition of) the use of a charging current irn which is equal to the previous charging current irn i multiplied by a chosen coefficient cc which is strictly less than one (i.e. irn = irn4*cc, with cc < 1).

[0077] For example, in step 10-70, the selected coefficient cc can be between 0.6 and 0.95. As an illustrative example, the selected coefficient cc can be 0.85. However, other values ​​for the selected coefficient cc can be used. For example, the value of the selected coefficient cc can be chosen during the development phase of the BC cell battery.

[0078] It should also be noted, as illustrated non-limitingly in [Fig. 1], that the battery calculator CB (or the management device calculator DG) may also include a mass memory MM1, in particular to store the total voltage ut, each cell voltage uc, each cell temperature te, the total state of charge ect, each cell state of charge ecc, the maximum state of charge ecm, the desired state of charge ecd, the possible minimum charging current that can be delivered by the power supply SA, the possible aging state of the cell battery BC, as well as any intermediate data involved in all its calculations and processing. Furthermore, this battery calculator CB (or the device calculator) The battery management device (DG) may also include an input interface (IE) for receiving at least the total voltage (ut), each cell voltage (uc), each cell temperature (te), the total state of charge (ect), each cell state of charge (ecc), the maximum state of charge (ecm), the desired state of charge (ecd), the possible minimum charging current that can be delivered by the power supply (SA), and the possible aging state of the cell battery (BC), for use in calculations or processing, possibly after shaping and / or demodulating and / or amplifying them, in a manner known per se, by means of a digital signal processor (PR2). Furthermore, this battery calculator (CB) (or the DG device calculator) may also include an output interface (IS), notably for delivering each message (or command) containing the definition of the imposed charging current, and each message (or command) to stop charging.

[0079] It will also be noted that the invention also proposes a computer program product (or computer program) comprising a set of instructions which, when executed by processing means of the type of electronic circuits (or hardware), such as for example the PR1 processor, is suitable for implementing the management process described above to manage the recharging of the BC cellular battery equipping the S system.

Claims

Demands

1. A method for managing the recharging of a cellular battery (CB) comprising electrochemical cells (EC) each having an estimated cell state of charge, a measured cell temperature and a measured cell voltage, and suitable for equipping a system (S), characterized in that it comprises a step (10-70) in which, in the event of a demand for recharging of said cellular battery (CB), at least one maximum recharging current is determined as a function of either said measured cell temperatures and measured cell voltages when said electrochemical cells (EC) have an open-circuit voltage curve as a function of their state of charge not exhibiting a plateau area, or said measured cell temperatures and said estimated cell states of charge when said electrochemical cells (EC) have an open-circuit voltage curve as a function of their state of charge exhibiting at least one plateau area.

2. Method according to claim 1, characterized in that in said step (10-70), in the presence of electrochemical cells (EC) having a curve of evolution of their open-circuit voltage as a function of their state of charge not exhibiting a plateau zone, each maximum charging current is determined as a function of the smallest and largest cell temperatures measured among all said cell temperatures measured and of the largest cell voltage measured among all said cell voltages measured.

3. Method according to claim 2, characterized in that in said step (10-70) a first lookup table is determined, establishing a correspondence between charging current values ​​and pairs of cell temperature and cell voltage, i) a first charging current value corresponding to said lowest measured cell temperature and highest measured cell voltage, and ii) a second charging current value corresponding to said highest measured cell temperature and highest measured cell voltage, and then said maximum charging current is determined by taking the smallest of said first and second charging current values ​​determined.

4. The method according to claim 1, characterized in that in said step (10-70), in the presence of electrochemical cells (ECs) having a curve of evolution of their open-circuit voltage as a function of their state of charge exhibiting at least one plateau area, each maximum recharge current is determined as a function of the smallest and largest cell temperatures measured among all said measured cell temperatures and the largest estimated cell charge state among all said estimated cell charge states.

5. Method according to claim 4, characterized in that in said step (10-70) a second lookup table, establishing a correspondence between charging current values ​​and pairs of cell temperature and cell charge state, is determined, i) a third charging current value corresponding to said smallest measured cell temperature and said largest estimated cell charge state, and ii) a fourth charging current value corresponding to said largest measured cell temperature and said largest estimated cell charge state, and then said maximum charging current is determined by taking the smallest of said third and fourth charging current values ​​determined.

6. A method according to any one of claims 1 to 5, characterized in that in said step (10-70) said charging is terminated when a voltage across said cell battery (BC) is equal to a voltage value chosen according to a desired total state of charge, and said maximum charging current has become less than a limit value for charge controllability.

7. Method according to claim 6, characterized in that in said step (10-70), when a partial recharge request is made, a corrected total state of charge is used, determined from an estimated total state of charge of said cell battery (BC) and a total state of charge inaccuracy margin.

8. Product computer program comprising a set of instructions which, when executed by processing means, is suitable for implementing the management method according to any one of claims 1 to 7 for managing the recharging of a cellular battery (BC) comprising electrochemical cells (CE) each having an estimated cell state of charge, a measured cell temperature and a measured cell voltage, and suitable for equipping a system (S).

9. A management device (MD) for managing the recharging of a cellular battery (CB) comprising electrochemical cells (EC), each having an estimated cell state of charge, a measured cell temperature, and a measured cell voltage, and suitable for equipping a system (S), characterized in that it comprises at least one processor (PR1) and at least one memory (MD) arranged to perform the operations consisting, in the event of a request to recharge said cellular battery (BC), of determining at least one maximum recharge current as a function of either said measured cellular temperatures and measured cellular voltages when said electrochemical cells (EC) have a curve of evolution of an open-circuit voltage as a function of their state of charge not exhibiting a plateau area, or said measured cellular temperatures and said estimated cellular states of charge when said electrochemical cells (EC) have a curve of evolution of an open-circuit voltage as a function of their state of charge exhibiting at least one plateau area.

10. System (S) comprising a cellular battery (BC) comprising electrochemical cells (CE) each having an estimated cell charge state, a measured cell temperature and a measured cell voltage, characterized in that it further comprises a management device (DG) according to claim 9.

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