Configurable battery with cell switching for increased reliability

Abstract

The present invention relates to a battery (10) comprising a branch (B) and a plurality of capacity units (12a-12d) interposed in series in the branch, each capacity unit having a main channel (16p) and an auxiliary channel (16s) mounted in parallel and each equipped with a switch (24p, 24s); the battery comprising, for each capacity unit, an electronic board (26a-26d) including a control unit (27a-27b) for the switches and a measurement circuitry (28a-28d) including, for each associated cell: - a differential amplifier (30) having an input connected to the positive terminal of the cell and an input connected to the negative terminal of the cell, and - two controllable current sources (32u, 32g) to pull the cell potential towards the positive voltage value or to ground. Figure for the abstract: Fig. 7

Description

Title of the invention: Configurable battery by cell switching with increased reliability. TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to the general field of accumulators, and more specifically to a battery particularly suitable for equipping an electric propulsion vehicle. TECHNICAL BACKGROUND

[0002] In the context of energy transition, the current trend is to gradually replace internal combustion engine vehicles with vehicles powered partially or totally by an electric motor.

[0003] Most manufacturers have opted to use batteries to store and release the electricity needed to operate the electric motor. A battery is a storage device that converts chemical energy into electrical energy to power the electric motor during its discharge phase, which in turn converts the electrical energy into mechanical work. Reversibly, the battery converts electrical energy back into chemical energy during its charging phase.

[0004] According to a conventional architecture as illustrated in [Fig. 1], an electric vehicle battery 1 is electrically connected to the electric motor 2, which drives the wheels 3 in rotation in response to the supply of electrical energy from the battery 1. This battery 1 is composed of several elementary units 4, called "cells," each consisting of a cathode, an anode, a separator, and an electrolyte. They are characterized primarily by their elementary voltage, typically from IV to 4V depending on the electrochemistry used.

[0005] Since these cells 4 are of low power, on the order of plus or minus 1 Watt, they are commonly associated in series and / or in parallel in a static configuration meeting the performance specifications required of the motor 2.

[0006] In this example, the cells 4 are installed in series of four forming sets called modules 5. These modules 5 are then connected in a network (series-parallel) so as to obtain the desired voltages / currents.

[0007] In practice, this involves forming the modules 5 by connecting cells 4 with rigorously equivalent parameters in series so as to tend towards a loading / unloading rate of these cells at the same rate. This feature stems from the fact that a variation in the load of the cells within the module quickly leads to cascading degradation, and then to failure.

[0008] Indeed, assuming that one of the cells in the module 5 under consideration discharges completely before the others when battery 1 is discharged to power the electric motor 2, the current flowing through it will drop to zero and battery 1 will appear to be completely discharged. If battery 1 is recharged, the cells will then charge until the healthy cells of module 3 reach their maximum charge, without allowing the completely discharged cell to fully charge, given that the healthy cells initially start with a non-zero charge. As can be understood, the completely discharged cell will then increase the battery's charge to a level below its maximum capacity.

[0009] Even if the cells are initially classified to form batches of cells that can be combined into modules 5, there remains some dispersion in elementary voltage, on the order of plus or minus 1%, due in particular to the fact that they are not all manufactured according to the same industrial process.

[0010] This dispersion will only increase naturally over time due to the effect of non-homogeneous aging of the cells as the charge / discharge cycles progress, until it reaches an order of magnitude of plus or minus 5%.

[0011] In order to solve this problem, manufacturers have implemented different technological solutions for cell balancing, including so-called passive balancing, and so-called active balancing.

[0012] With reference to [Fig. 2], "passive balancing" consists of discharging cells that are more charged than others in a module 5 in isolation in order to eliminate the voltage difference. This technique typically involves integrating, for each cell 2, a circuit 6 connected to its terminal, which is equipped with a switch and a resistor of approximately 20Ω. Closing the circuit 6 with the switch thus induces the discharge of the cell in question.

[0013] In the example of [Fig. 2], a module 5 is considered, comprising three cells CELL 1, CELL 2, and CELL 3, whose charge level is schematically represented by bars. Since CELL 2 is less charged than CELL 1 and CELL 3 in this example, the passive balancing logic involves discharging CELL 1 and CELL 3 to align with the voltage of CELL 2.

[0014] With reference to [Fig. 3], "acting balancing" consists of balancing the charge level of the cells in a module by recharging a cell with a low charge level with energy extracted from cells with a higher charge level. Based on the three-cell arrangement CELL 1, CELL 2, and CELL 3 in [Fig. 2], [Fig. 3] illustrates the recharging dynamics of CELL 2 by drawing on the CELL 1 stores. CELL 2 charges simultaneously with the discharge of CELL 1, each tending towards the charge value of CELL 3.

[0015] These various technologies, while effective, consist of lowering the charge level of the cells to smooth them towards an average state. Part of the energy accumulated in the cells is thus used for purposes other than powering motor 2. This leads to the need to find a solution that adapts to the imbalance of the cells without reducing their energy output.

[0016] Ongoing research into solutions has revealed the relevance of integrating switches based on a "power balancing" logic. This logic aims to select, precisely when needed, whether to use a cell or group of cells by adjusting the actuation of these switches. As can be understood, such an architecture makes it possible to regulate the charge level of the cells by discriminating, during battery charging or discharging, which cells to use and which to isolate.

[0017] However, the use of such switches along the current line adds complexity to the battery due to its partitioning, which is a source of failure.

[0018] Following the logic of "power balancing", the aim of the invention is to propose a robust battery architecture to justify its integration into a vehicle. Description of the invention

[0019] To this end, the invention relates to a configurable battery for powering an electric vehicle motor, this battery comprising: - a branch defined between an upper limit and a lower limit, the lower limit being defined as ground; and - a plurality of capacity units, each interposed between two connection nodes along the branch, each capacity unit comprising: — a two-track circuit with parallel tracks between the two nodes, comprising a main track and an auxiliary track, — at least one cell interposed in the main pathway, — a set of two switches comprising a first switch interposed in the main track and a second switch interposed in the auxiliary track; the battery also includes, for each unit of capacity, an electronic circuit board comprising: - a control unit adapted to selectively control the opening and closing of each of the switches of the corresponding capacity unit and - a measurement circuitry ensuring the acquisition of parameters of said at least one cell of the corresponding capacity unit, including the voltage across its terminals; characterized in that the measurement circuitry of the electronic boards comprises, for each cell: - a differential amplifier comprising a first input connected to the positive terminal of the cell by a first connecting wire and a second input connected to the negative terminal of the cell by a second connecting wire; and - two controllable current sources, including: — a first current source connected to the first connecting wire, the activation of which pulls the cell's potential towards the positive voltage value of the battery; and — a second current source connected to the second connecting wire and whose activation pulls the cell potential towards the battery reference ground.

[0020] The invention also relates to a battery defined as follows, further comprising for each cell: - a voltage limiting device which is interposed along the first connecting wire provided between said cell and the corresponding differential amplifier, in a series configuration; and / or - two voltage limiting devices, each mounted in parallel at one of the respective cell terminals.

[0021] The invention also relates to a battery thus defined, in which the voltage limiting devices are interposed along the first connecting wires and referenced to the potential of the node corresponding to the node of the capacity unit that is closest to the lower terminal of the battery.

[0022] The invention also relates to a battery thus defined, in which the voltage limiting devices are inductors.

[0023] The invention also relates to a battery defined as follows, in which: - the voltage limiting devices are each mounted in parallel at one of the respective cell terminals; - These voltage limiting devices are voltage limiting diodes connected to the battery ground, for example Zener diodes or Transit diodes

[0024] The invention also relates to a battery thus defined, comprising both voltage limiting devices mounted in series along the first connecting wires and voltage limiting devices mounted in parallel at the terminals of the cells.

[0025] The invention also relates to a vehicle propelled partially or totally by an electric motor and comprising a battery thus defined to power the electric motor.

[0026] The invention also relates to a method for diagnosing a cell of a battery thus defined in a charging or discharging state, comprising the following steps: - SI) "standard" acquisition of the voltage across said at least one cell of a capacitance unit on the basis of the difference of voltages measured at the level of the two inputs of the corresponding differential amplifier; - S2) "verification" acquisition of the voltage across said at least one cell by means of the difference of the voltages recorded at the level of the two inputs of the differential amplifiers during the activation of one or the other of the first and second controllable current sources; - S3) "verification" acquisition of the voltage across said at least one cell by means of the difference of the voltages recorded at the level of the two inputs of the differential amplifiers during the activation of the other controllable current source than that activated in step S2); - S4) comparison of the voltage values ​​obtained in steps SI and S2 and S3.

[0027] The invention also relates to a diagnostic method thus defined for a cell of a capacity unit that is not under load or discharge, comprising the following steps: - SI') acquisition of the voltage across said at least one cell by means of the difference of the voltages measured at the level of the two inputs of the corresponding differential amplifier, by activating one or the other of the first and second controllable current sources; - S2') acquisition of the voltage across said at least one cell by means of the difference of the voltages measured at the level of the two inputs of the corresponding differential amplifier, by activating the other controllable current source than that activated in step SI'); - S3') comparison of voltage values ​​obtained in steps SI' and S2'. Brief description of the drawings

[0028] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the accompanying drawings in which: - [Fig.l], already described, is a diagram of the installation of a battery in a vehicle equipped with an electric motor that generates a rotational torque on the wheels; - [Fig.2], already described, is a representation of a load balancing of cells installed in series following a passive logic, called "passive balancing"; - [Fig.3], already described, is a representation of a load balancing of cells installed in series following an active logic, called "active balancing"; - [Fig. 4] is a schematic and partial view of a battery according to the invention, comprising a branch along which capacity units are mounted in series, each unit comprising a main circuitry path along which several cells are mounted in series and an auxiliary circuit track mounted in parallel with the main track; a set of two switches, one of which is interposed in the main track and the other is interposed in the auxiliary track; - [Fig.5] is a schematic view that illustrates the control of the switches of the capacity units by electronic boards in a battery according to the invention; - [Fig.6] is an illustrative representation of a problem of measuring voltage across the terminals of cells connected in series; - [Fig.7] is a partial branch view which illustrates a circuitry for measuring capacitance unit cells according to a first particular aspect of the invention; - [Fig.8] illustrates a redundancy of power supply of electronic boards for controlling the switches of the capacity units according to a second particular aspect of the invention; - [Fig.9] illustrates a variant of the arrangement comprising voltage limiters according to a third aspect of the invention; - [Fig. 10] illustrates another variant of the arrangement comprising voltage limiters according to the third aspect of the invention; - [Fig. 11] illustrates an example of the implementation of a countermeasure circuit according to a fourth particular aspect of the invention; - [Fig. 12] illustrates another example of the realization of a countermeasure circuit according to the fourth particular aspect of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] The idea behind the invention is to propose a battery architecture following a "power balancing" logic allowing the decision to be made, precisely as needed, whether or not to use a cell.

[0030] With reference to [Fig. 4], a battery 10 according to the invention comprises a branch B mounted between an upper terminal Ts and a lower terminal Ti which is connected to ground Gnd. This branch B is provided with capacity units, collectively designated as 12, arranged in series and each comprising one or more cells 14 which can be considered as elementary batteries.

[0031] In this example, branch B is equipped with four capacity units, referenced 12a, 12b, 12c and 12d, each comprising four cells 14 mounted in series.

[0032] It is understood that the invention is not strictly limited to the example in [Fig. 4]. A different number of capacity units 12 and a different number of cells 14 per capacity unit 12 may be used, in particular a single cell 14. In practice, the number of capacity units 12 and constituent cells 14 is determined according to the cost-energy requirements balance for a given application.

[0033] Also, the battery 10 can very well comprise several branches B mounted in parallel between the upper and lower terminals Ts, Ti; a single branch B having one or more capacity units 12, or several branches of which at least one is provided with a capacity unit 12.

[0034] In detail, each capacity unit 12 comprises a circuit with two parallel channels 16p, 16s, connected at the circuit ends to each other by two nodes 20, 22, including a main channel 16p and an auxiliary bypass channel 16s. Node 22 corresponds to the node in the batch that is closer to the lower terminal than node 20.

[0035] The cells 14 of each capacitance unit 12 are interposed in series within the main channel 16p, alternating their polarity, namely by connecting the positive terminal of one to the negative terminal of the one directly adjacent to it. In this way, the voltages measured across the cells 14, also called electromotive forces, are added along the main channel 16p in the expression for the voltage measured between nodes 20, 22. In the example in [Fig. 4], this voltage measured between the two nodes 20, 22 of a capacitance unit 12 is denoted V followed by the reference "a", "b", "c", "d" indicating the positioning of the capacitance unit 12 along branch B. For example, the voltage associated with unit 12a is denoted Va, while the voltage associated with unit 12d is denoted Vd.

[0036] These main and auxiliary channels 16p, 16s are each further equipped with a controlled switch, respectively designated by 24p, 24s. Transistors are advantageously used as switches 24p, 24s to electrically control their conducting or blocking state of current, but the invention is not limited to this feature.

[0037] The invention aims to modulate the opening and closing of the switches of each of the capacity units 12 so as to: - to stress their cells 14 by charging / discharging the battery 10 by forcing the current to flow along the main channel 16p by closing the switch 24p of the main channel 16p and opening the switch 24s of the auxiliary channel 16s; and additionally - isolate their cells 14 from the charging / discharging phenomenon of the battery 10 by forcing the routing of the current along the auxiliary channel 16s via the opening of the switch 24p of the main channel 16p and the closing of the switch 24s of the auxiliary channel 16s.

[0038] With reference to [Fig. 5], the battery 10 comprises electronic boards 26 for managing the capacity units 12. Advantageously, the battery is provided with as many electronic boards 26 as there are capacity units 12. In the example of [Fig. 5], four electronic boards 26a-26d are distinguished, each associated with a capacity unit. 12a-12d separate. These electronic boards 26a-26d include at least one control unit 27a-27d designed to control the opening and closing of the switches 24p, 24s of the associated capacity unit 12. As shown schematically by dashed arrows, the control units 27a-27d control the switches 24p, 24s by transmitting to them a respective command Cp, Cs.

[0039] In practice, the actuation of switches 24p, 24s of the main and auxiliary tracks 16p, 16s follows an alternating dynamic: when one is open, the other is closed. This alternation of open / closed state of switches 24p, 24s ensures an uninterrupted flow of current under normal operating conditions by ensuring that a flow path is always available.

[0040] With this architecture, it is thus possible to activate or not activate the cell(s) 14 of each capacity unit 12. In practice, this amounts to adding or not adding the voltage generated on either side of the cells 14 of each capacity unit 12, namely the potential difference between the nodes 20 and 22, to the expression of the general voltage Vt of the battery 10 measured between the lower terminal Ti and the upper terminal Ts.

[0041] In the context of the invention, it is recommended to instrument each capacitance unit 12a-12d with a measurement circuitry 28a-28d ensuring the measurement of certain characteristic parameters of the cell state. This measurement circuitry 28a-28d is an integral part of the electronic boards 26a-26d and includes, for example, voltage measurement sensors across each cell and temperature sensors for each cell.

[0042] In addition, the electronic boards 26a-26d are equipped with a diagnostic unit 29a-29d, such as a microcontroller-type computer. This diagnostic unit 29a-29d analyzes the acquisition measurements of the measuring circuitry 28a-28d, for example by comparing the potential difference measured at each cell, and communicates its analysis results to the control unit 27a-27d, which can then decide on the preferred current routing by actuating the switches.

[0043] By means of voltage measurements and analyses, a control unit 27a-27d can, in particular, prevent any observed imbalance between the cells 14 of the associated capacitance unit 12 from manifesting by separating them. In the example of [Fig. 5], the set of cells 14 of the capacitance units 12a and 12c are shown with different charge states, which results in a voltage imbalance. They are therefore separated by preventing current from flowing along the main channels 16p of the capacitance units 12a and 12c.

[0044] Similarly, if a temperature measurement sensor indicates that a cell 14 of the corresponding capacity unit 12 is overheating, it may be considered to control the opening of the 24p switch of the main 16p channel and the closing of the 24s switch of the auxiliary 16s channel for safety purposes.

[0045] It should be noted that the management of the battery 10 according to the invention is not limited to a particular protocol, such as isolating the cells 14 of a capacity unit 12 on the sole basis of the identification of a voltage irregularity or a temperature anomaly.

[0046] For example, the battery architecture according to the invention, due to its modular nature, is particularly well-suited for use in an electric vehicle to power its electric motor. Indeed, an electric vehicle motor has a variable input voltage requirement, which depends in particular on the mechanical power to be delivered to the wheels to satisfy a driver demand (pedal pressure). The battery 10 according to the invention makes it possible to directly supply an appropriate voltage Vt and current It in real time to the electric motor, ensuring operation at nominal speed at a given operating point, by activating the cells 14 as needed through the actuation of the switches 24p, 24s of the capacity units 12.

[0047] The battery 10 according to the invention thus makes it possible to do without the use of voltage converters which are classically connected between the electric motor and a conventional type battery to align the output voltage of the battery with the motor requirements.

[0048] Following a reverse logic, the battery 10 can be controlled to deliver a constant overall voltage value Vt or to deliver any optimal voltage profile by driving the capacity units 12 in this way.

[0049] The battery structure 10 described on the basis of Figures 4 and 5 provides real flexibility in configuration, which is of particular interest for its integration into a vehicle.

[0050] However, integrating the 24p, 24s switches, advantageously in the form of transistors, adds a layer of complexity. Solutions according to the invention will be described below, enabling the battery 10 to achieve a level of integrity that meets the most stringent ASIL (Automotive Safety Integrity Levels) standards, justifying its integration into a vehicle.

[0051] According to a first particular aspect of the invention, the aim is to increase the robustness of the battery 10 by refining the voltage diagnosis of the cells 14 in order to eliminate measurement errors which can lead to poor management of the switches 24p, 24s by the electronic boards 26.

[0052] Generally speaking, it is difficult to provide a direct individual voltage measurement of each cell 14 because the measurement reference point cannot be changed relative to ground along branch B. In other words, when A simple voltage measurement is performed; the measured voltage represents the sum of the voltages of all the cells interposed between the cell being measured and the reference ground of branch B. Referring to [Fig. 6], which illustrates an arbitrary circuit comprising four cells connected in series, a voltage measurement of the first cell, labeled Cell 1, is possible since its end is connected to ground (Gnd), while it is only possible to measure the voltage of the other cells in relation to the preceding cells. For example, a voltage measurement at the cell furthest from ground, labeled Cell 4, is equivalent to measuring the voltage of all four cells (Cell 1 - Cell 4) together.

[0053] To measure the individual voltage across the terminals of each cell 14 in the case of the battery 10 according to the invention, namely the potential difference between the cathode and the anode, it is recommended to equip the measurement circuitry 28 with subtractor amplifiers 30, also called differential amplifiers, each associated with a separate cell 14.

[0054] With reference to [Fig.7], these amplifiers 30 are each configured with one output and two inputs, including a "+" input, called non-inverting, which is connected to the positive terminal of the associated cell by a first connecting wire 31p and a "-" input, called inverting, connected to the negative terminal of this cell by a second connecting wire 31n.

[0055] As understood, the inverting input "-" of the amplifier 30 associated with a cell 14 corresponds to the non-inverting input "+" of the amplifier 30 associated with the cell 14 directly juxtaposed below along the main channel 16p of a capacitance unit 12. In the same way, such a commonality of connection is found between the non-inverting input "+" of the amplifier 30 associated with a given cell and the inverting input "-" of the amplifier 30 associated with the cell 14 directly juxtaposed above.

[0056] Thus, for a given cell 14, the signal recorded at the inverting input "-" of the associated amplifier 30 corresponds to the existing voltage referred to ground upstream of this cell, that is to say, it corresponds to the sum of the voltages of the cells 14 which are interposed between the given cell and the ground of the battery 10. As for the signal recorded at the non-inverting input "+", it corresponds to the existing voltage directly downstream of the given cell, namely, it corresponds to the existing voltage upstream of the given cell plus the voltage specific to this cell.

[0057] At the output, the amplifier 30 provides information on the individual voltage of the cell 14 to which it is connected by calculating the difference between the voltages measured at the two inputs. As can be understood, the use of such differential amplifiers 30 makes it possible to isolate the voltage of each cell 14.

[0058] In general, differential amplifiers 30 are sized to operate over predefined input voltage ranges.

[0059] It should be noted, however, that when the cells 14 of a capacitance unit 12 are isolated by opening the switch 24p of the main channel 16p, or in the event of an unexpected disconnection of a cell 14, the differential amplifiers 30 operate outside these predefined input voltage ranges. Indeed, in such a situation of disconnection or current routing along the auxiliary channel 16s, the reference to the conventional power supply ground is lost. Consequently, the measuring circuitry 28 is no longer referenced to a multiple of the cells, and a so-called "floating" situation arises, which induces a debiasing of the measuring circuitry 28.

[0060] Such depolarization generates voltage measurement errors, resulting in an uncertain diagnosis by the diagnostic unit 29. Specifically, the diagnostic unit 29 may incorrectly identify a cell as healthy, a so-called "false positive," or conversely, incorrectly identify a cell as damaged, a so-called "false negative," based on incorrect measurements. This situation can then lead the control unit 27 to direct the current inappropriately.

[0061] The example in [Fig. 7] illustrates the two specific cases in which a depolarization of the measuring circuitry 28 occurs: a first capacitance unit 12a has a cell disconnection identified by D, while the cells of a second capacitance unit 12b are isolated. In this example, the capacitance units 12a and 12b have four cells numbered from 1 to 4. The voltage associated with each cell 1-4 is denoted V1-V4.

[0062] To overcome such a situation, it is in principle a matter of mapping the activation / connection state of the cells 14 to validate or reject the acquisition voltages recorded by the measurement circuitry 28.

[0063] The integration of the 24p, 24s switches within the framework of the invention has the advantage of guaranteeing current flow even if a cell 14 is disconnected, but this nevertheless makes the activation / connection state mapping delicate. Indeed, residual capacitances may remain across the terminals of isolated or disconnected cells 14, induced by the current flowing along the switches.

[0064] In order to allow evaluation of the activation / connection state of the cells 14 and thus to determine the validity of the voltage acquisition measurements, it is recommended according to the invention to enrich the measurement circuitry 28 with controllable current sources which are connected to the inverting inputs "-" and non-inverting inputs "+" of the differential amplifiers 30.

[0065] For each differential amplifier 30: - a first controllable current source 32u is connected to the connecting wire 31p provided between the non-inverting "+" input and the positive terminal of the corresponding cell 14; and - a first controllable current source 32g is connected to the connecting wire 31n provided between the inverting "-" input and the negative terminal of cell 14.

[0066] The first controllable current source 32u, called "pull-up", allows for upward bias, namely pulling the potential of the cell 14 towards the positive supply value of the battery, while the second controllable current source 32g, called "pull-down", allows for downward bias, that is to say tends to force the potential towards the reference ground Gnd of the battery 10.

[0067] With this arrangement, it becomes possible to detect and locate any failure by measuring the voltage across each cell 14 without activating the controllable current sources and then comparing it to the acquisition results obtained by selectively activating the first controllable current source 32u and the second controllable current source 32g.

[0068] In detail, this first aspect of the battery 10 according to the invention makes it possible to ensure reliable voltage monitoring of the cells 14 of each capacity unit 12 by means of: - a first step SI) of measurement called "standard" in voltage at the terminals of each cell 14 via the differential amplifiers 30, without activating the controllable current sources 32u, 32g; - a second measurement step S2) called "verification" in voltage across the terminals of each cell 14 via the differential amplifiers 30, by activating one or the other of the first and second controllable current sources 32u, 32g; - a third step S3) of "verification" measurement in voltage across the terminals of each cell 14 via the differential amplifiers 30, by activating the other controllable current source 32u, 32g of that activated during the second step S2; - a fourth step S4) of comparison of the voltage values ​​obtained in the three steps SI, S2 and S3 allowing to confirm the validity of the standard measurements or on the contrary to alert the diagnostic unit 29 that the basic measurements are erroneous so as to prevent an inadequate actuation of the switches 24p, 24s by the control unit 27.

[0069] It should be noted that the measurements carried out in the second step S2 and in the third step S3 are complementary in that the disconnection of a cell 14 can occur at the level of its positive pole as well as at the level of its negative pole.

[0070] In practice, when an anomaly is detected in a given cell 14, evidenced by voltage values ​​obtained at the three stages S1, S2, and S3 that do not coincide, it is advantageously recommended to isolate the capacitance unit 12 to which this given cell belongs. In other words, it is recommended in the event of an anomaly potential measurement taken at the level of a capacity unit 12 whose cells 14 are being used to provide a countermeasure of exclusion of its cells 14 by the control unit 27 by ensuring a bypass of the current along the auxiliary track 16s by opening the switch 24p of the main track 16p.

[0071] By allowing precise control of the voltage across the cells 14, the measuring circuitry 28 according to this first aspect of the invention enables the battery 10 to satisfactorily regulate its capacity units 12 by disconnecting them when a fault is identified. By thus performing its self-diagnosis and activating switches 24p, 24s on this basis to isolate the fault, it is understood that the battery 10 according to this first aspect of the invention makes it possible both to limit failures and therefore the maintenance steps they require. Also, given that the location of faults is known to the battery 10, it follows, where necessary, that maintenance is easier and faster by replacing the capacity unit 12 with a disconnected cell with a healthy capacity unit 12.

[0072] It should also be noted that this measurement circuit architecture 28 conveniently allows for an assessment of the connection status of the cells 14 during battery 10 startup, i.e., before the voltage Vt is established. In practice, when the vehicle starts, it is possible, within the scope of the invention, to activate the controllable current sources 32u, 32g and to perform the "verification" voltage measurements across the terminals of each cell 14 described in steps S2 and S3. Obtaining different voltage values ​​for a cell 14 indicates a cell disconnection. In such a case, it is necessary to ensure the current is routed along the auxiliary channel 16s of the corresponding capacitor unit 12.

[0073] According to a second particular aspect of the invention, the aim is to increase the operational safety of the battery 10 by limiting the risk of loss of control of the switches 24p, 24s of the capacity units 12 by the electronic cards 26.

[0074] In practice, an under-powering of the electronic boards 26 can lead to their malfunction and therefore to chaotic management of the switches 24p, 24s, quickly leading to the ruin of the battery 10.

[0075] In detail, such an under-supply situation can lead, in charging as well as discharging the battery 10, to current interruptions in the battery 10 by simultaneous opening of switches 24p, 24s, or lead to short circuits in cells 14 in the opposite case of simultaneous closing of switches 24p, 24s.

[0076] As is understood, the integration of the 24p, 24s switches into the battery 10 requires maintaining control of the 24p, 24s switches while ensuring that the electronic boards 26 are not under-powered.

[0077] On this basis, it is recommended, according to the second aspect of the invention, to create a redundancy of power supply for the electronic boards 26, namely to multiply the physical sources of electrical power supply ensuring the operation of the measurement circuitry and the diagnostic and control units.

[0078] In this sense, it is intended that each electronic card 26 is powered by drawing from the cells 14 belonging to: - a first unit of capacity 12, advantageously the one that is directly controlled by the electronic board in question; and - at least one other capacity unit 12, different from the first, in which case this first capacity unit may not be able to meet the expected characteristics in powering the electronic board.

[0079] It should be noted that adopting such power supply redundancy for the electronic boards 26a-26d, by drawing on the charge of the cells 14 of different capacity units 12a-12d, requires overcoming a potential reference constraint. Since, in the case of battery 10 operation, the cells 14 can be selectively activated or isolated depending on the open / closed state of the switches 24p, 24s, it follows that the potential at each point of branch B is said to be "floating". Specifically, the potentials at the points connecting the series of cells 14 of the capacity units 12 can shift from one another.

[0080] To enable a shared energy transfer from the cells 14 of different capacity units 12 of branch B to power the same electronic board 26, it is decided according to the invention to provide power supply circuits which integrate DC / DC transformers allowing the voltage of an associated capacity unit 12 to be transferred to an isolated voltage, namely to change the ground potential.

[0081] By way of example, [Fig.8] illustrates an arrangement in which the electronic boards 26a and 26b, which respectively control the capacity units 12a, 12b of the battery 10, are powered by the cells 14 of these capacity units 12a, 12b.

[0082] As understood, the power supply for the first electronic board 26a is provided by the cells 14 of the first capacitor unit 12a that it drives, as well as by the cells 14 of the second capacitor unit 12b directly adjacent to it. Conversely, the power supply for the second electronic board 26b is provided by the cells 14 of the second capacitor unit 12b that it drives and by the cells 14 of the first capacitor unit 12a directly adjacent to it.

[0083] With regard to the power supply of the first electronic board 26a, the battery 10 includes a power supply circuit comprising a first power supply sub-circuit associated with the first capacity unit 12a and a second power supply sub-circuit associated with the second capacity unit 12b.

[0084] In detail, the first power supply sub-circuit of the first card 26a is in the form of a loop comprising: - a first input line 40a which draws the direct current directly from the so-called upper terminal Bs of the series of cells 14 of the first capacity unit 12a, denoted ia direct, to the first electronic board 26a; and - a first output line 42a which carries this direct current ia direct output from the first electronic board 26a to the lower terminal Bi of the series of cells 14 of the first capacity unit 12a to close the current loop associated with this first capacity unit 12a.

[0085] As regards the second power supply sub-circuit of the first card 26a, it is also in the form of a loop comprising: - a second input line 40b which carries the current from the so-called upper terminal B s of the series of cells 14 of the second capacity unit 12b to the first electronic board 26a; and - a second output line 42b which carries the current from the output of the first electronic board 26a to the lower terminal Bi of the series of cells 14 of the second capacity unit 12b to close the current loop associated with this second capacity unit 12b.

[0086] Note that in order to allow the supply of the first electronic board 26a by means of the two currents ia and ib despite the floating nature of the points of the branch B to which the first and second capacitance units 12a, 12b belong, it is recommended to interpose a first isolated DC / DC converter 44 in the second sub-circuit.

[0087] This first DC / DC 44 converter is intended for both: - transform, along the second input line 40b, the direct current, noted ib direct, which is drawn from the upper terminal Bs of the second capacitance unit 12b, into a direct current ib dc / dc which is referred to the ground potential of the first capacitance unit 12a, noted refl2a, upstream of the first electronic board 26a; and - restore the direct current ib direct along the second output line 42b, downstream of the first electronic board 26a, by transforming the direct current ib dc / dc back into a direct current ib, namely into a current referred to the ground potential of the second capacitance unit 12b, noted refl2b, so that it can return to this second capacitance unit 12b.

[0088] In practice, the second input line 40b is split on either side of the DC / DC converter 44 into: - an upstream pre-transformation portion 40b 1 which carries the direct current ib, taken from the upper terminal Bs of the series of cells 14 of the second capacity unit 12b, to an input of the DC / DC converter 44 to be transformed into a DC / DC current ib compatible with sharing with the direct current ia flowing along the first sub-circuit to power the first electronic board 26a; and - an upstream post-transformation portion 40b2 which extends from an output of the DC / DC converter 44 to the first electronic board 26a to supply it with said current ib dc / dc at the end of its transformation at the level of the DC / DC converter 44.

[0089] Similarly, the second output line 42b can be split on either side of the DC / DC converter 44 into: - a downstream post-transformation portion 42b2 which carries the current ib dc / dc downstream of the first electronic board 26a to an input of the DC / DC converter 44; - a downstream return portion 42b 1 which connects an output of the DC / DC converter 44 to the lower terminal Bi of the series of cells 14 of the second capacitance unit 12b, to reinject the current ib which has been counterbalanced in its direct ib form into the DC / DC converter 44 from the dc / dc ib current.

[0090] As understood, the first DC / DC converter 44 equips the second power supply subcircuit to conform the current ib so that it is aligned with the ground potential of the first capacitance unit 12a, in the form ib dc / dc, and thus be eligible to supply the first electronic board 26a commonly with the direct current ia, before restoring it to its original direct ib form to return to the second capacitance unit 12b.

[0091] In addition, the power supply circuit of the first electronic board 26a is provided with two diode modules, identified by 46 and 48. These diode modules 46 and 48 each form a sharing / de-sharing interface between the first and second power supply sub-circuits at the input and output of the first electronic board 26a.

[0092] The first diode module 46 is positioned upstream of the first electronic board 26a. It has an output which is connected to the power supply input of the first electronic board 26a by a line labeled 49i, and two inputs, including: - an input connected to the first input line 40a along which the direct current ia flows, and - an input connected to the upstream post-transformation line 40b2 of the second input line 40b which carries the ib dc / dc current.

[0093] In practice, this first diode module 46 performs a power supply function, also known as electronic decoupling, which discriminates between input currents by allowing the current ia direct or ib dc / dc with the highest voltage to flow, namely the current most likely to meet the minimum current required by the electronic board 26a, i.e., its nominal current. As understood, this first diode module 46 ensures a continuous power supply to the electronic board 26a with a sufficient current level by substituting the faulty current ia direct with the current ib dc / dc, and vice versa.

[0094] The second diode module 48 is located downstream of the first electronic board 26a. It has an input which is connected to the power supply output of the first electronic board 26a by a line labeled 49s, and two outputs, including: - an output connected to the first output line 42a along which the direct current ia flows, and - an output connected to the downstream post-transformation line 42b2 of the second output line 42b which carries the current ib dc / dc.

[0095] This second diode module 48 ensures, in the same way as for the first diode module 48, the decoupling of the direct ia and dc / dc ib currents at the output of the first electronic board 26a.

[0096] It should also be noted that by nature, the diode modules 46 and 48 provide an anti-reflux function, namely they impose the direction of current flow, indicated by arrows on [Fig.8], from the capacitance units 12a, 12b to the first electronic board 26a on the way out, and then from the first electronic board 26a to the capacitance units 12a, 12b on the return of the current.

[0097] The power supply topology of the first electronic board 26a has been explained as involving a conversion of the direct current ib to match the ground potential refl2a of the current ia so as to create a compatible power supply.

[0098] The power supply for the second electronic board 26b follows the same logic, except that the current ia is this time subjected to conversion by a second isolated DC / DC converter, while the current ib remains unchanged. A second DC / DC converter, denoted 54, is thus recommended to transform the current ia to match the ground potential, ref 12b, of the second capacitor unit 12b and thus make it compatible with sharing with the current ib, and then to restore the current ia to the original ground potential, namely the ground potential ref 12a of the first capacitor unit 12a.

[0099] In detail, the power supply of the second electronic board 26b is provided by the battery 10 by means of a first power supply sub-circuit associated with the second capacity unit 12b and a second power supply sub-circuit associated with the first capacity unit 12a.

[0100] The first power supply sub-circuit of the second electronic board 26b is in the form of a loop comprising: - a first input line 50b which draws the direct current, ib direct, directly taken from the upper terminal B s of the series of cells 14 of the second capacitance unit 12b to the second electronic board 26b; and - a first output line 52b which carries this direct DC current ib from the output of the second electronic board 26b to the lower terminal Bi of the series of cells 14 of the second 12b capacity unit to close the current loop associated with this second 12b capacity unit.

[0101] As regards the second power supply sub-circuit of the second electronic board 26b, it is also in the form of a loop comprising: - a second input line 50a which carries the current from the upper terminal Bs of the series of cells 14 of the first capacitance unit 12a to the second electronic board 26b; and - a second output line 52a which carries the current from the output of the second electronic board 26b to the lower terminal Bi of the series of cells 14 of the first capacity unit 12a to close the current loop associated with this first capacity unit 12a.

[0102] To allow the second electronic board 26b to be powered by the two currents ia and ib despite the floating nature of the points in branch B, the second isolated DC / DC converter 54 is interposed in the second input and output lines 50a, 52a of the second sub-circuit. This second DC / DC converter 54 allows both: - transform, along the second input line 50b, the direct current ia direct, which is drawn from the upper terminal Bs of the first capacitance unit 12a, into a direct current ia dc / dc which is referred to the ground potential refl2b of the second capacitance unit 12b, upstream of the second electronic board 26b; and - restore the direct current ia direct along the second output line 52a, downstream of the second electronic board 26b, by transforming the direct current ia dc / dc back into a direct current ia, aligned with the ground potential refl2a of the first capacitance unit 12a, so that it can return to this first capacitance unit 12a.

[0103] In a manner analogous to the arrangement described of the second power supply subcircuit of the first electronic board 26a, the second input line 50b and the second output line 52b of the second power supply subcircuit of the second electronic board 26b can be discretized into two portions on either side of the DC / DC converter 54.

[0104] Thus, we can identify along the second input line 50a: - an upstream pre-transformation section 50al which carries the direct current ia, taken from the upper terminal Bs of the series of cells 14 of the first capacitor unit 12a, to an input of the DC / DC converter 54 where it is transformed into a DC / DC current ia compatible with the direct current ib flowing along the first sub-circuit to power the second electronic board 26b; and - an upstream post-transformation section 50a2 which extends from an output of the DC / DC converter 54 to the second electronic board 26b to power it with said current ia dc / dc obtained at the end of its transformation at the level of the DC / DC converter 54.

[0105] Similarly, the second output line 52a can be split on either side of the second DC / DC converter 54 into: - a post-transformation downstream portion 52a2 which carries the current ia dc / dc downstream of the second electronic board 26b to an input of the DC / DC converter 54; and - a return downstream portion 52al which connects an output of the DC / DC converter 54 to the lower terminal Bi of the series of cells 14 of the first capacitor unit 12b, to reinject the current ia which has been counterbalanced in its direct form ia into the DC / DC converter 54 from the current ia dc / dc.

[0106] Similarly to the power supply circuit of the first electronic board 26a, the power supply circuit of the second electronic board 26b is provided with two diode modules, identified by 56 and 58. These diode modules 56 and 58 each form a sharing / de-sharing interface between the first and second power supply sub-circuits at the input and output of the second electronic board 26b.

[0107] The first diode module 56 is arranged upstream of the second electronic board 26b. It has an output which is connected to the power supply input of the second electronic board 26b by a line marked 59i, and two inputs of which: - an input connected to the first input line 50b along which the direct current ib passes, and - an input connected to the upstream post-transformer line 50a2 of the second input line 50a which carries the current ia dc / dc.

[0108] The second diode module 58 is located downstream of the second electronic board 26b. It has an input which is connected to the power supply output of the second electronic board 26b by a line labeled 59s, and two outputs, including: - an output connected to the first output line 52b along which the direct current ib flows, and - an output connected to the downstream post-transformation line 52a2 of the second output line 52a which carries the current ia dc / dc.

[0109] The redundancy of power supply has been explained on the basis of the example of [Fig.8] in which the electronic boards 26a, 26b driving the juxtaposed capacity units 12a, 12b of the battery 10 are powered by the cells 14 of these capacity units via DC / DC converters ensuring the compatibility of the currents ia and ib.

[0110] This redundancy logic is applicable to all the electronic boards 26 of the battery 10. It should be noted, however, that the invention is not strictly limited to a particular number or condition of juxtaposition of the capacity units 12 used. Specifically, the use of isolated DC / DC converters allows to power an electronic control board 26 for a given capacity unit 12 with cells from at least one other capacity unit 12 by transferring the voltage of the current drawn from this other capacity unit 12 to the isolated voltage compatible with the electronic control board 26. In practice, although it is advantageously preferred for ease of connection that the electronic control boards 26 each be powered by the cells 14 of the capacity unit 12 it drives and at least one adjacent unit as in the example in [Fig. 8], the invention is not strictly limited to this feature. As understood, the power supply redundancy of a given electronic control board 26 can be ensured by the cells 14 of two or more capacity units 12, regardless of their relative position in the battery 10, provided that isolated DC / DC converters are provided in accordance with the invention.

[0111] Finally, it should be noted that the battery 10 according to this second aspect is not strictly limited to the use of a diode module. In practice, any electronic equipment or group of electronic equipment that allows the currents supplied by the cells 14 of the capacity units 12 to be prioritized for powering the same electronic board 26 can be used as a substitute for a diode module as illustrated.

[0112] According to a third particular aspect of the invention, the aim is to increase the reliability of battery 10 by limiting the risk of damage by overvoltage of the constituent elements of battery 10.

[0113] During the operating life of the battery 10, a disconnection or unexpected failure of a cell 14 of a capacity unit 12 along branch B may occur. A disconnection of cell 14 may be caused, in particular, by vibrations generated when the vehicle equipped with the battery 10 is in motion, or by any other cause creating a local voltage increase. For example, a large current variation may induce overvoltages in the cells.

[0114] If the capacity unit 12, one of whose cells is faulty / disconnected, is subjected to charging or discharging the battery 10, namely when the switch 24p of the main channel 16p is closed and the switch 24s of the auxiliary channel 16s is open, then a sudden spike in voltage occurs between the upper terminal Ts of the battery 10 and the faulty / disconnected cell.

[0115] This voltage peak, depending on the location of the fault / disconnection along branch B, can be significantly higher than the maximum voltage value that the constituent elements of the battery 10, in particular the cells 14, can withstand. Such an electrical overvoltage stress event can thus lead to damage to the electronic components enabling the diagnosis of the cells 14, or even the destruction of the battery 10.

[0116] In the absence of being able to predict the occurrence of a failure or disconnection of cell 14, it is recommended in this third particular aspect of the invention to prevent the appearance of the voltage peak, or at least to limit the voltage seen by the diagnostic components during the peak, by means of the use of voltage limiters 60.

[0117] According to an example of an arrangement, illustrated in [Fig. 9], the measuring circuitry 28 of the capacitance units 12 is equipped with voltage limiters 60, each associated with a corresponding cell 14. These voltage limiters 60 are in the form of modules, each interposed in a series arrangement along the connecting wire 31p provided between the positive terminal of a cell 14 and the non-inverting "+" input of the corresponding differential amplifier 30. Each voltage limiter 60 is advantageously referenced to the potential of the lower part of the capacitance unit 12, namely referenced to node 22, which ensures a maximum voltage not to be exceeded between the lower reference and the line of the cell to be diagnosed.

[0118] In this example, the voltage limiters 60 can be of any type, passive or active, provided that they are compatible with a series connection with the power line, such as an inductor, a semiconductor block, or a block with a biased magnetic core.

[0119] With this arrangement, any overvoltage incident along branch B, and more specifically along the main channel 16p of the capacitance units 12, does not affect the measuring circuitry 28, which is protected by the voltage limiters 60 acting as barriers. It follows that the current received by the measuring circuitry 28 always remains below a maximum voltage limit to which its components can be subjected without damage.

[0120] It should be noted that the third particular aspect of the invention is not strictly limited to the arrangement in [Fig. 9], in which the voltage limiters are installed in series between the cells 14 and the differential amplifiers 30 of the measuring circuitry 28, along the first connecting wires 31p. Alternatively, a parallel arrangement of the voltage limiters 60 may be used.

[0121] As an example of a variant of the parallel arrangement, [Fig.10] illustrates a capacity unit 12 of the battery 10 which is equipped with voltage limiters 60 in the form of Zener diodes arranged between the cells 14. In detail, each cell 14 is equipped with two voltage limiters 60 each placed in parallel at one of the terminals and connected to the ground Gnd of the battery 10.

[0122] This particular arrangement with two voltage limiters 60 connected to the terminals of the cells 14 makes it possible to counteract the occurrence of an overvoltage resulting from: - a disconnection between a cell terminal and the main channel 16p of the capacitance unit 12 in which it is interposed; or - a disruption of the main 16p pathway caused between two cells 14; - an intrinsic failure of cell 14.

[0123] These diodes 60, characterized by a so-called "breakdown" voltage, also called the "Zener voltage," allow a portion of the current flowing along the main channel 16p to be diverted when the voltage exceeds the breakdown voltage. As can be understood, if the input voltage, namely the voltage measured across the cell 14 with which the Zener diode 60 is connected in parallel, increases to a value exceeding the breakdown voltage, a portion of the current flows through the diode 60 instead of along the main channel 16p.

[0124] Based on this, the Zener diodes used are configured to block any unwanted voltage rise beyond a predefined value, corresponding to a voltage acceptance ceiling at the terminal of the corresponding cell 14. It follows that the current flowing along the main channel 16p always satisfies a maximum voltage ceiling to which the constituent components of the battery 10 can be subjected without degradation. They are judiciously used within the framework of the invention by taking care to limit their current and reduce their leakage in order to minimize diagnostic measurement errors.

[0125] Also, Zener 60 diodes are judiciously used in combination with resistors, not shown, to limit the intensity of the current through them to an admissible value, namely to a value that they can withstand.

[0126] It should be noted that the arrangement in [Fig. 10] is not specifically limited to the use of such Zener diodes as voltage limiters 60. In practice, any type of device allowing a maximum voltage to be imposed along the main channel 16p of the capacitance units 12, in particular across the cells 14, can be used within the meaning of the present invention. By way of example, the Zener diodes can be replaced by so-called Transit diodes.

[0127] Finally, it should be noted that a mixed arrangement can be used within the framework of this third particular aspect of the invention to combine their respective advantages, namely an arrangement that includes both: - voltage limiters 60 arranged in series along the connecting wires 31p linking the main channel 16p of the capacitance units 12 to the differential amplifiers 30 of the measuring circuitry 28, in accordance with the arrangement of [Fig.9]; and - voltage limiters 60 arranged in parallel across the terminals of the cells 14, based on the example of [Fig.10].

[0128] It should in particular be emphasized that the integration of voltage limiters 60 can also find its application in a generic battery architecture which includes a plurality of cells installed in series to provide an overall voltage which is greater than the voltage which these cells can withstand.

[0129] According to a fourth particular aspect of the invention, the aim is to increase the operational reliability of the battery 10 by incrementing a countermeasure solution to a failure of the switches 24p, 24s of capacity units 12 or a failure of control of these switches by the associated electronic boards 26.

[0130] In a failure situation characterized by a lack of response or an inadequate response of the switches 24p, 24s to a given setpoint, or even chaotic control of the switches 24p, 24s by an electronic board 26, then these cases can lead to severe cases: - interruption of current in case of simultaneous opening of these switches, or - short circuit of cells 14 in case of simultaneous closing of the switches.

[0131] To avoid such events severely impacting the integrity of the battery 10, it is recommended according to this fourth aspect to enrich it with bypass circuits 70, from the English "by-pass", allowing the current, in discharge or charge of the battery 10, flowing along branch B so that it does not pass through the capacity units 12.

[0132] The example in [Fig. 11] illustrates two capacitance units 12a, 12b, each driven by a separate electronic board 26a-26b. Each capacitance unit 12 is assigned a bypass circuit 70 in the form of an electrical channel 72 along which a switch 74 is interposed. Advantageously, and without limitation, this switch 74 is a transistor.

[0133] In detail, the electrical path 72 of each bypass circuit 70 extends between two ends which are each grafted to a node 20, 22 of the capacity unit 12 considered, so as to form an external current routing path different from the main and auxiliary paths 16p, 16s.

[0134] Each bypass circuit 70 is allocated an electronic card 76 for controlling the switch 74, which sends a control command Cb for opening or closing.

[0135] When the switch 74 of a given bypass circuit is opened, it is understood that said bypass circuit 70 is non-working, that is, it has no influence on the current flowing through the capacity unit 12. Conversely, closing the switch 74 creates a preferential path for the current to flow along the electrical path 72 of the bypass circuit 70, so that it no longer flows along the main path 16p or the auxiliary path 16s of the capacity unit 12. In other words, when the switch 74 is closed, the bypass circuit 70 ensures a current diversion between the nodes 20 and 22 that connect the capacity unit 12. In such a case, the electrical path 72 of the bypass circuit 70 becomes comparable to a portion of a battery branch 10 that is devoid of cells 14.

[0136] It should be noted that the scope of the invention is not restricted to the example of [Fig. 1 1] in which a bypass circuit 70 is allocated to each capacitance unit 12. It is understood here that an arrangement may be considered in which a bypass circuit 70 provides a current diversion along several juxtaposed capacitance units along branch B.

[0137] Fig. 12 illustrates this particularity in particular by associating, as a non-limiting example, two by two the capacity units 12a-12d of branch B of battery 10 with a bypass circuit 70. In this example, we distinguish an electronic board denoted 26ab which controls capacity units 12a and 12b, and an electronic board denoted 26cd which controls capacity units 12c and 12d.

[0138] According to this arrangement, the electrical path 72 of each bypass circuit 70 is connected to the so-called extremum nodes 20, 22, namely, bounding the series of juxtaposed capacity units 12, to allow the current to bypass them as needed.

[0139] A current diversion along several juxtaposed capacitance units 12 by the same bypass circuit 70 is particularly preferable if these capacitance units are controlled by the same electronic board 26 as illustrated in [Fig. 7]. Indeed, a switch control corruption by the electronic board 26 can generalize to all the capacitance units allocated to it.

[0140] Each bypass circuit 70 is preferably controlled by a separate electronic card 76, but an arrangement with several bypass circuits 70 controlled by the same electronic card 76 does not fall outside the scope of the invention.

[0141] Generally, the aim is for the bypass circuits 70 to be able to reroute the current as quickly as possible in the event of a detected failure. To this end, the battery 10 incorporates a communication network 80 enabling the fault information to be relayed to the electronic board 76, which controls the appropriate countermeasure bypass circuit 70.

[0142] This network 80 comprises, firstly, main communication channels 82 between each electronic card 26 for controlling a capacity unit 12 and the electronic card 76 for controlling the bypass circuit 70 associated with the capacity unit in question. By way of illustration, the electronic card labeled 26a in [Fig. 10], which controls the capacity unit 12a, is connected by a main communication channel 82 to the electronic card 76 associated with it.

[0143] In the case where a 24p, 24s switch of unit capacity 12 is the cause of the failure, for example when it does not respond satisfactorily to the control instruction Cp, Cs which is transmitted to it by its electronic card 26, the latter is able to transmit the information of the failure up the main communication channel 82.

[0144] Also, the network 80 includes secondary communication channels 84 ensuring dialogue between the electronic boards 26 controlling the capacity units 12 or between the electronic boards 76 controlling the bypass circuits 70. These secondary communication channels 84 allow the detection of a fault to be relayed to the appropriate electronic board 76 for countermeasures via one or more other electronic boards forming a relay point.

[0145] These secondary communication channels 84 thus ensure transmission of the fault detection even if the electronic board 26 of the faulty capacity unit 12 is unable to communicate directly with the appropriate countermeasure electronic board 76. Specifically, the electronic board 26 of the faulty capacity unit 12 sends a transmission message along all the communication channels 82, 84, so that the fault identification information has a significantly greater chance of reaching the appropriate countermeasure electronic board 76.

[0146] In practice, the primary and secondary communication channels 82, 84 of the network 80 are also subject to a risk of failure. In order to maintain control over information routing, these channels are formed independently of each other. Thus, if one channel is unexpectedly interrupted, for example, the other channels can simultaneously transmit the fault detection information successfully.

[0147] It is also advantageously recommended that each electronic card 26, 76 be capable of detecting faulty communication on the communication channels 82, 84 with which it cooperates by means of a "watchdog" type control mechanism. As will be understood, these control mechanisms, denoted 85, allow the electronic cards 26, 76 to recognize an anomaly in the routing of information on a channel and to exclude it from the information management.

[0148] Also, to ensure that a failure occurring on a given capacity unit 12 or on its associated electronic board 26 does not affect the control of the bypass circuit 70 designed to counteract it, the power supply of the electronic board 76 controlling this bypass circuit 70 is intended to be independent of these components. In Figures 9 and 10, the power supply of the electronic boards 26 controlling the capacity units 12 is collectively designated AL26; while the power supply of the electronic boards 76 controlling the bypass circuits 70 is designated AL76.

[0149] By way of example, if the electronic board 26 driving one or more capacity units 12 is powered (AL26) by the cells 14 of this or these capacity units, in accordance with the preferred embodiment described in the third aspect of the invention, these cells 14 are not used for the power supply (AL76) of the electronic board 76 for controlling the bypass circuit 70.

[0150] Powering the electronic control boards 76 for the bypass circuits 70 with a separate current source AL76 from the battery 10 is certainly advantageous. As a non-limiting example, these electronic boards 76 could be conveniently powered by the 12V SLI battery, from the English "starting-lighting-ignition," which is standard equipment in all vehicles to ensure the proper functioning of critical systems.

[0151] In the same way as for the power supply of the electronic boards 26 as described in the second specific aspect of the invention, it is advantageous to multiply the power supply sources for the electronic boards 76 in the form of redundancies. Indeed, given that the bypass circuits 70 each form a safety barrier against damage to the battery 10 resulting from a failure of the capacity units 12 or the electronic boards 26 that monitor them, a redundant power supply for the electronic boards 76 that control them makes it possible to meet the highest overall reliability requirements.

[0152] Finally, within the framework of this fourth aspect according to the invention, a second safety curtain is advantageously erected in the event of failure of a bypass circuit 70 or of its control by the associated electronic card 76.

[0153] In concrete terms, a critical situation may arise in which the bypass circuit 70, which corresponds to the first safety curtain, does not fulfill its role of diverting the current along its electrical path 72 when the capacity unit 12 assigned to it is faulty.

[0154] This second safety curtain consists of blocking in a controlled manner the passage of current along branch B whose capacity unit 12 is faulty, advantageously by means of a fuse 86 which can receive a cut-off instruction from all the electronic boards by means of an independent safety wire 88.

[0155] The management of the capacity units 12 has been defined so far on the basis of temperature and voltage measurements of the cells 14 by the electronic boards 26, while the implementation of the means of countermeasures has been explained as being based on the assessment of compliance with the opening / closing instructions of the switches 24p, 24s and 74 conditioning the routing of the current.

[0156] It should be noted that the transistors used to construct switches 24p, 24s, and 74 are semiconductor elements with a certain impedance and voltage and temperature acceptance ranges. In practice, a current that may be acceptable for cells 14 is not necessarily acceptable for a given transistor, which can lead to excessive heating and damage.

[0157] Since these limitations must also be taken into account in the management of the capacity units 12 and the means of countermeasures, the electronic cards 26, 76, and more specifically their measurement circuitry, are enriched with temperature and voltage measurement sensors at the terminals of the switches 24p, 24s and 74 which they supervise.

[0158] Based on this incrementation of temperature and voltage measurement sensors at the terminals of transistors 24p, 24s, 74, it has notably made it possible, according to a fifth particular aspect of the invention, to strengthen the control of the battery 10, and consequently of the electrical behavior of the vehicle equipped with it.

[0159] In general, the integration of transistors 24p, 24s, 74 into the battery 10 is likely to interfere with the voltage measurements of the cells 14, particularly because their impedance is added to that of the cells. Specifically, when a voltage measurement is taken across a cell 14, the voltage value obtained also depends on whether the transistors are open or closed.

[0160] Similarly, the presence of transistors 24p, 24s, 74 in the battery 10 is also likely to skew the temperature measurements of the cells 14. Since even the slightest current flowing through a transistor causes it to heat up, this results in a rise in the ambient temperature around it. Consequently, the temperature measured at a given cell 14, depending on its relative position with a transistor, could be artificially inflated. This could lead to an undesirable situation where the cells 14 of a capacitance unit 12 are incorrectly isolated due to an excessively high operating temperature reading.

[0161] With knowledge of the temperature and voltage across the transistors, as well as their position in the battery, it becomes possible to refine the voltage and temperature measurements of the cells 14 so as to avoid such a situation.

[0162] Within the framework of this fifth particular aspect, it is thus proposed that the diagnostic units 29 of the electronic boards 26 for controlling the capacity units 12 take into account the temperature and voltage measured at the transistors in their assessment of the parameters of cells 14. Specifically, it is a matter of formulating a phenomenological model for assessing the performance of the cells 14 which provides information on the expected acquisition values ​​in temperature and voltage across each cell 14 of the capacity units 12 according to the closed or open state of the switches.

[0163] This model can be generated as follows: - SI) collect satisfactory temperature and voltage ranges across the terminals of each cell 14 considered in isolation, according to manufacturer standards; - S2) quantify the influence of opening or closing the transistors on the temperature and voltage values ​​acquired across each cell 14 based on temperature and voltage measurements across the transistors acting as switches 24p, 24s of capacity units 12, and also bypass circuits 60 as part of the fourth aspect; - S3) define satisfactory inherent temperature and voltage ranges across the terminals of each cell 14 of the battery 10.

[0164] It should also be noted that the knowledge gathered regarding the voltage and temperature of transistors 24p, 24s, and 74 makes it possible to construct a predictive model of the expected performance of battery 10 based on the conducting or blocking state of these transistors 24p, 24s, and 74, which is more accurate than a model built on the basis of cell voltage and temperature. This model can serve as the basis for real-time control of battery 10 according to the vehicle's needs.

[0165] This knowledge, correlated with a measurement of the intensity (It) of the current passing through branch B, also makes it possible to model the battery 10 in real time and in particular to enrich the behavioral model of the battery 10 on the basis of the series impedance of the cells 14 which varies according to the conducting or blocking state of the transistors 24p, 24s, 74. Such a model allows a precise evaluation of the capacity of the battery 10 to supply or receive current as a function of the activation state of the transistors 24p, 24s, 74.

[0166] This model can also serve as an indicator of failure during operation of the battery 10. In practice, if the battery 10 exhibits performance below, or at least different from, that expected for a given configuration, this situation indicates a failure. "Configuration" is understood to mean the resultant of all the openings / closings of switches 24p, 24s, 74 that determine whether or not the cells 14 are activated, as expressed in the current It and voltage Vt values ​​of the current carried along branch B of the battery 10.

[0167] The various particular aspects of the battery 10 according to the invention have been described in isolation from one another, but it should be noted that the invention obviously allows them to be combined partially, or totally, to move towards the most optimized architecture.

Claims

1. Demands Configurable battery (10) to power an electric vehicle motor, comprising: - a branch (B) defined between an upper limit (Ts) and a lower limit (Ti), the lower limit (Ti) being defined at ground; and - a plurality of capacity units (12a-12d) interposed each between two connection nodes (20, 22) along the branch (B), each capacity unit (12) comprising: — a two-way circuit (16p, 16s) mounted in parallel between the two nodes (20, 22), including a main channel (16p) and an auxiliary channel (14s), — at least one cell (14) interposed in the main pathway (16p); — a set of two switches (24p, 24s) comprising a first switch (24p) interposed in the main track (16p) and a second switch (24s) interposed in the auxiliary track (14s); the battery (10) further comprising, for each capacity unit (12a-12d), an electronic board (26a-26d) including: - a control unit (27a-27b) adapted to selectively control the opening and closing of each of the switches (24p, 24s) of the corresponding capacity unit (12a-12d) and - a measurement circuitry (28a-28d) ensuring the acquisition of parameters of said at least one cell (14) of the corresponding capacity unit (12a-12d), whose voltage (V1-V4) across its terminals; characterized in that the measurement circuitry (28a-28d) of the electronic boards (26a-26d) comprises for each cell (14): - a differential amplifier (30) comprising a first input connected to the positive terminal of the cell (14) by a first connecting wire (31p) and a second input connected to the negative terminal of the cell (14) by a second connecting wire (31n); and - two controllable current sources (32u, 32g) including: — a first current source (32u) connected to the first connecting wire (31p) and whose activation pulls the potential of the cell (14) towards the positive voltage value of the battery (10); and — a second current source (32g) connected to the second connecting wire (31n) and whose activation pulls the potential of the cell (14) towards the reference ground of the battery (10).

2. Battery (10) according to claim 1, further comprising for each cell (14): - a voltage limiting device (60) which is interposed along the first connecting wire (31p) provided between said cell (14) and the corresponding differential amplifier (30), in a series arrangement; and / or - two voltage limiting devices (60) which are each mounted in parallel at one of the respective cell (14) terminals.

3. Battery (10) according to claim 2, wherein the voltage limiting devices (60) are interposed along the first connecting wires (31p) and referenced to the potential of the node (22) corresponding to the node of the capacity unit that is closest to the lower terminal (Ti) of battery (10).

4. Battery (10) according to claim 2, wherein the voltage limiting devices (60) are inductors.

5. Battery (10) according to claim 2, wherein: - the voltage limiting devices (60) are each connected in parallel at one of the respective cell terminals (14); - these voltage limiting devices (60) are voltage limiting diodes connected to the ground (Gnd) of the battery (10), for example Zener diodes or Transit diodes

6. Battery (10) according to any one of the preceding claims, comprising both voltage limiting devices (60) mounted in series along the first connecting wires (31p) and voltage limiting devices (60) mounted in parallel across the terminals of the cells (14).

7. Vehicle propelled partially or totally by an electric motor and comprising a battery (10) according to any one of the preceding claims for powering the electric motor.

8. A method for diagnosing a cell (14) of a battery (10) according to any one of claims 1 to 6 under charging or discharging conditions, comprising the following steps: - S1) "standard" acquisition of the voltage across said at least one cell (14) of a capacity unit (12a-12d) based on the voltage difference measured at the two inputs of the corresponding differential amplifier (30); - S2) "verification" acquisition of the voltage across said at least one cell (14) by means of the voltage difference - S3) "verification" acquisition of the voltage across said at least one cell (14) by means of the difference of the voltages measured at the two inputs of the differential amplifiers (30) during the activation of the other controllable current source (32u, 32g) than that activated in step S2); - S4) comparison of the voltage values ​​obtained in steps S1 and S2 and S3.

9. A method for diagnosing a cell (14) of a capacity unit (12a-12d) of a battery (10) according to any one of claims 1 to 6 which is not under load or discharge, comprising the following steps: - S1') acquiring the voltage across said at least one cell (14) by means of the difference of the voltages measured at the two inputs of the corresponding differential amplifier (30), by activating either of the first and second controllable current sources (32u, 32g); - S2') acquiring the voltage across said at least one cell (14) by means of the difference of the voltages measured at the two inputs of the corresponding differential amplifier (30), by activating the other controllable current source (32u, 32g) than that activated in step S1'); - S3') comparison of voltage values ​​obtained in steps SI' and S2'.

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