SEMI-MODULAR BATTERY MANAGEMENT SYSTEM

Description

DOMAINE TECHNIQUE DE L'INVENTION

[0001] The present invention relates generally to the field of storage batteries, in particular lithium storage batteries. ETAT DE LA TECHNIQUE ANTERIEURE

[0002] Storage batteries consist of electrochemical cells that can be connected in series or parallel to achieve the required voltage and current. A lithium battery that has exceeded its nominal operating parameters may "appear" to be working properly, but present a risk of overheating or fire.

[0003] Lithium batteries therefore require protection circuits. Typically, these circuits measure voltage, current, and temperature, and control a current-limiting and cut-off device.

[0004] In case of short circuit or overcurrent, it is necessary to disconnect the battery to avoid damage and to avoid excessive heating of the battery or its connection cables.

[0005] Typically, electromechanical circuit breakers or fuses are used, or electronic circuits are used to measure current and control a cut-off device. However, measuring current is not simple.

[0006] There are several methods of current measurement (shunt, magnetic measurement or by thermal effect). However, these can involve high consumption, which may require the use of a "standby" mode and an "active" mode. This is difficult to reconcile with short-circuit protection, which can intervene at any time.

[0007] In addition, a thermal engine starter battery must provide a very high current for a few seconds to a few tens of seconds. Also, the circuit breaker current must be set to a fairly high value, around half the short-circuit current (the maximum power supplied is reached when the voltage is half the no-load voltage, and the current is half the short-circuit current).

[0008] With aging, or at low temperatures, the internal resistance of the battery cells increases, thus the short-circuit current decreases. It is possible that this current becomes lower than the trip current. In this case, protection is no longer guaranteed. Improper use can lead to a complete discharge of the battery in its internal resistance, causing excessive heating, then a fire.

[0009] Finally, for example and without limitation, a non-modular 17 Ah battery can provide a short-circuit current of more than 2000 A. Thus, a cut-off device must be able to withstand this current. Semiconductors capable of withstanding this current are not common and in practice, several lower current components are connected in parallel. Current balancing is very difficult to achieve, which requires oversizing the components. Measuring a 2000 A current also poses problems of compromise between accuracy and static consumption.

[0010] Several devices have been proposed to secure batteries and in particular to monitor their condition, and if necessary, to cause the electronic circuit to be cut off, particularly in the event of short circuits.

[0011] In addition, these systems must have a means of monitoring and a means of breaking or opening the circuit. Several different mechanisms exist, with their advantages and disadvantages.

[0012] Several systems include a more or less sophisticated battery management system (BMS) to monitor the condition of a battery, battery accumulators and / or to act on the battery circuit to open it in the event of a problem.

[0013] Thus, document EP2092627 proposes a battery management system (BMS) comprising two current inputs and one output. The document teaches the use of a shunt when the battery is fully charged. The accumulators are arranged in series with a cut-off device to cut off in the event of a short circuit. The BMS measures the voltage and temperature at each accumulator arranged in series. Accumulators can be added one after the other to increase the delivered voltage, and the increase in current must be followed by a resizing of the components. The BMS is responsible, at each point, for measuring the balance of each accumulator in order to balance the battery. In other words, we have the equivalent of one BMS per cell. This document finally proposes placing a MOSFET ("Charge control") between the input (terminal +) and the accumulators, and another MOSFET ("Discharge Control") between the output (terminal -) and the accumulators.

[0014] CN110265738 proposes a different lithium cell group control system, which monitors the temperature, current and voltage of parts of the circuit. This allows for overcurrent detection / protection as well as charging current limitation.

[0015] The BMS of True Blue Power batteries has a very large number of components, numerous electronic boards, and numerous connectors. This penalizes costs and reliability. The BMS has 2 operating modes, "standby and active" and a micro-cut every hour is observed in standby mode. The cut-off device has several MOSFETs in parallel. Such a solution involves current balance problems in the different MOSFETs, requires power components that must be oversized, finally the current measurement results in high consumption of the current measuring device and therefore significant self-discharge.

[0016] There are also complex battery management devices such as the one taught in patent application WO 2018095039 A1, which describes a remote intelligent battery management system, comprising: at least two battery packs, a data analysis center and a terminal monitor. Each battery pack is equipped with a set of lithium batteries, a battery management system (BMS) module, a GPS communication module and a 4G communication module.The BMS module is used to obtain the data of the lithium battery pack and manage the lithium battery pack; the GPS module is used to obtain the location data of the geographic information of the lithium battery pack; the 4G communication module is used to transmit the data of the lithium battery pack and the location data of the geographic information to the data analysis center by means of a base station; the data analysis center is equipped with a data testing center, a data storage center, and a cloud-based artificial intelligence battery analysis center. The remote intelligent battery management system can adjust a management policy of a BMS in real time, and control the charging and discharging conditions of the lithium battery packs, so that the safety of the batteries is greatly improved.By determining the operating conditions of lithium battery packs, after-sales communication costs are reduced, and the utilization rate and repair rate of lithium battery packs are improved.

[0017] In this device, the decision-making and storage organ is located outside the battery. The battery management module is only used to collect measurements and send them to a data analysis center, which then detects anomalies and makes battery management decisions.

[0018] Also known is EP2562555A1 which describes a battery pack comprising a plurality of battery units connected in parallel with each other, each comprising a cell group in which one or two or more secondary cells are connected in series, and a first current control element which is connected in series to this cell group, a first control means which controls the charge / discharge current for each battery unit by controlling the operation of the first current control element included in each of the battery units; a voltage measuring means which measures the voltage of the one or more cell groups included in each of the battery units, and a diagnosis means which diagnoses a deterioration level or a defect of each battery unit on the basis of the voltage of the one or more cell groups measured by the voltage measuring means.

[0019] Finally, document US2018 / 026456A1 is known, which describes a battery system comprising a plurality of battery modules connected in parallel. Each battery module comprises a battery, a first output terminal and a second output terminal, a switching circuit connected between the battery and the first output terminal, and a battery manager for detecting a battery voltage of the battery and controlling the switching circuit. Each battery manager is connected to other battery managers via a communication bus and transmits module information of a corresponding battery module to the other battery managers via the bus. Each battery manager also receives module information from the other battery managers via the bus and controls a corresponding switching circuit based on the module information.

[0020] However, the prior art solutions have drawbacks because they propose accumulator batteries that are difficult to modulate while maintaining good balancing of the different accumulators and good reliability and safety. In addition, the proposed solutions describe architectures using external, even remote, elements, which causes the multiplication of wiring and / or other components rather than a simple architecture internal to the battery. EXPOSE DE L'INVENTION

[0021] The present invention therefore aims to propose a semi-modular battery management system (BMS) for accumulators, making it possible to overcome at least some of the drawbacks of the prior art.

[0022] This object is achieved by a battery management system (BMS) for accumulators of a semi-modular element as defined by independent claim 1. Particular embodiments of the invention are defined by the dependent claims. BREVE DESCRIPTION DES FIGURES

[0023] Other characteristics, details and advantages of the invention will emerge from reading the description which follows with reference to the appended figures, which illustrate: [ Fig. 1 ] represents a functional diagram of the battery circuit according to a particular embodiment [ Fig. 2 ] represents a simplified structural diagram of part of the battery circuit. [ Fig. 3 ] represents a diagram of a part of the circuit showing the structure and operation of the cut-off member upon discharge of the circuit breaker device and its actuation by the opening of a MOSFET, in a particular embodiment. [ Fig. 4 ] represents a diagram of part of the circuit showing the structure and operation of the cut-off device responsible for the disconnecting device and its actuation by an optocoupler, in a particular embodiment. [ Fig. 5 ] represents a schematic view of the battery comprising several lines of accumulators, fixed by PCBs including the top PCB, the battery further comprising the fixed BMS. [ Fig. 6 ] represents a front sectional view of the battery along the XX' axis passing through a line of accumulators. [ Fig. 7 ] represents a schematic view in longitudinal section passing through the axis XX' passing through a line of accumulators. [ Fig. 8 ] schematically represents the circuit of the upper and lower PCBs of the battery pack. [ Fig. 9 ] represents the display of the changes in the voltage at the terminals of comparators U1 and U2 in the event of overcurrent according to an embodiment for a 24.4 Volt battery and trigger voltage Td of 16 Volts [ Fig. 10 ] represents the response of a digital integrator assembly operating according to the logic diagram of the figure 12 according to an embodiment used with a 16 Volt battery and a trigger voltage Td of 12 Volts; [ Fig. 11 ] represents the response of an analog integrator assembly according to another analog embodiment used with a 16 Volt battery and a trigger voltage Td of 12 Volts and; [ Fig. 12 ] a flowchart explaining the program for calculating the response of a digital integrator assembly according to an embodiment with parallel connection of the analog embodiments; DESCRIPTION DETAILLEE DE L'INVENTION

[0024] Many combinations can be envisaged without departing from the scope of the invention; the person skilled in the art will choose one or the other depending on the economic, ergonomic, dimensional or other constraints that he must respect.

[0025] In general, the present invention comprises a battery management system (BMS) for accumulators of a semi-modular element comprising a plurality of lithium cellular elements connected in series to form a line, and comprising at least two series lines connected in parallel constituting the semi-modular element, and at least one detection circuit characterized in that the detection circuit comprises at least one device for detecting discharge or short circuit and at least one device for monitoring the voltage and temperature of a cellular or modular element, the detection circuit controlling a disconnection device comprising a cut-off member per line.

[0026] Advantageously, the battery comprises at least two lines of cellular elements in parallel, each line having its cut-off device. The BMS is also configured to carry out measurements on each line of cellular elements forming accumulator lines in order to be able to cut off a faulty block from the circuit independently of the others. This allows in particular the battery to remain functional, by delivering a lower maximum current but without the voltage of the series-parallel battery being changed. Thus, the breakdown is avoided despite the failure of one or part of the accumulators of the battery.

[0027] In certain embodiments, the detection circuit is connected on the one hand to the negative or positive pole of each set of cells or each battery and on the other hand to the negative and positive terminal of the battery and uses at least two, preferably only two, MOSFETs M1, M2 per line; a first MOSFET M1 performing a circuit cut-off in the event of discharge below a threshold or during a short circuit, a second MOSFET M2 performing a load cut-off in the event of an element of said circuit being exceeded, in voltage or temperature, the voltage or temperature, the circuit further comprising electronic components (diode, resistors, capacitor), for example around the second MOSFET M2 performing a load current limitation, each line comprising a load cut-off member, a discharge cut-off member, and a load current limitation member.

[0028] The presence and use of MOSFETs on each battery line as charging and discharging cut-off devices advantageously allows the faulty line to be specifically cut off from the circuit.

[0029] Protection against short circuits, overcurrents and deep discharge allows the values ​​determined as thresholds to be respected. The system of the present invention activates the battery disconnection if the voltage and duration reach said threshold values. The electronics also incorporate a charging current limiting device, and protection in the event of failure of the device's alternator or charger.

[0030] It is clear that the components allowing this limitation to the charge are not on the discharge circuit, but on the charge circuit / line.

[0031] In some embodiments, the first MOSFET (M1) is connected by its source to the negative terminal of a set of cells, this first MOSFET (M1) receives on its gate a voltage source (V2) which drives (M1) this source delivering a chosen voltage (for example 6 to 10 V) so that the first MOSFET (M1) is conducting, a Zener diode (D3) is connected in opposition between the gate and the source of the first MOSFET (M1) and a capacitor (C2) protect the gate of the first MOSFET (M1) from excessively high or high frequency voltages and a Zener diode (D1) mounted in opposition between the gate of the first MOSFET (M1) and the drain and in series with a resistor (R3) and a diode (D2) in the conducting direction in the drain-gate direction, (D1, D2, R3) limiting the switching speed of the first MOSFET (M1) and a circuit consisting of a Schottky diode (D4) limits the current dump,this Schottky diode (D4) is mounted in opposition on the drain of the first MOSFET (M1) in the charging direction and in series with a capacitor C1 and a resistor R1 connected to the positive terminal of the battery to also limit the overvoltage when the first MOSFET M1 opens, in parallel on the Schottky diode (D4) is mounted a resistor I1 connected on the one hand to the cathode of the diode and on the other hand to the drain of the second MOSFET (M2) whose source is connected to the anode of the Schottky diode (D4), the gate of the second MOSFET (M2) being controlled by an output of the detection circuit to prevent charging.,

[0032] Advantageously, this assembly makes it possible to limit the switching speed of M1, to limit the overvoltage when M1 opens and also to limit the current during charging.

[0033] In some embodiments, the second MOSFET M2 is connected by its gate to the base of the phototransistor of an optocoupler whose emitter is connected to the source of M2, between these two points are connected a zener diode D5 and a capacitor C5, by the BMS card, the light-emitting diode of the optocoupler is connected by its cathode to the negative terminal of the battery or of the modular assembly of cells and receives on its anode the command sending a current in the LED in the event of exceeding the voltage or temperature of a detected element.

[0034] Advantageously, this arrangement allows the circuit or a line of the circuit to be cut off by decision of the BMS, particularly in the event of a voltage or temperature exceeding a detected element.

[0035] In some embodiments, the arrangement of the disconnection circuit associated with the two MOSFETs is interposed between the output pole of a line and the same terminal, of the same polarity (positive or negative) of the battery.

[0036] In some embodiments, the BMS is connected to and controls each cell element and each battery line in the circuit and monitors the voltage of each cell and each series line of cells.

[0037] This advantageously allows the battery to be secured at the individual accumulator level. Indeed, one accumulator could be faulty and unbalance the other batteries, leading to a security breach.

[0038] Preferably, the circuit does not include a shunt as shown in the figure 2 The principle is to take a proportion of the voltage from each cell or each parallel set of cells. On the figure 2 each set of parallel cells (V4, V9, V13, V17, V21) are connected on the one hand each on one polarity to the cathode of a respective diode (D1, D2, D3, D4), each diode having as common point its anode to carry out an OR function and on the other hand by the other polarity with one end of a divider bridge (R1, R2, R3, R4) connected by its other end to the common point of the anodes for the first set of cells mounted in parallel as shown at the top of the figure 2 in the square (undervoltage). The voltage proportional to the OR of the voltages of each cell is used, either analogically by a comparator supplied on its other terminal by a reference voltage or digitally as explained below.

[0039] The principle of measurement via an integrator assembly as described in the present application is a principle of measuring an overall voltage which makes it possible to return to a current value. This principle is only valid in the battery field when the internal resistance of the voltage generator is known. In this case and only in this case, the said integrator assembly can be used either in analog (as shown in the figure 2 ) or digitally.

[0040] For example, and without limitation, the response or output of a digital integrator can be calculated as follows:

[0041] Let a variation of the voltage be represented by x = (-0.25 * global V + 2.5) * weighting, where global V is a voltage obtained from the battery voltage by using a voltage divider bridge (R1-R2 or R9-R4) and weighting is a variable that allows the integration constant to be changed. The equation above can be modified depending on the accumulators used.

[0042] The output or response, y, of the numerical integrator having the general form y = Integration(x), where Integration( ) represents the integral calculus, can be calculated using either as a first progression equation consisting of taking the value of x, defined above, and raising it to an even power (2, 4, 6, 8...), for example y = x 2< . A second progression equation is given by y= Rate *(-In(x)), with Rate, the integration constant expressed in seconds.

[0043] To get even closer to the analog integrator ( figures 9 , 11 ), a second progression equation defined, for example and in a non-limiting manner, by y= Rate *(-In(x)), with Rate, an integration constant expressed in seconds, can be used. This equation makes it possible to imitate the behavior of a capacitor whose voltage at its terminals evolves as an exponential.

[0044] There figure 12 represents a calculation diagram of the response of a digital integrator according to the second progressive equation. Each calculation step represents the components of the detection device that may be involved in the calculation operations. The diagram can be divided into three phases: measurement phase (MP) and comparison, integration phase (IP) and disjunction phase (DP).

[0045] In the measurement phase (PM), the voltage divider bridge R1-R2 (or R9-R4) makes it possible to determine an overall V=V measurement of the voltage at the input of the detection device from the battery voltage V1.

[0046] The variable "Refintegration" is the integration reference and corresponds to a voltage value below which the input signal V will be integrated. If the voltage V is greater than the variable "Refintegration", we are in a situation where the battery is functioning normally. If V is less than the variable "Refintegration", the battery is functioning abnormally and the process that can lead to the disconnection of said battery is triggered. This variable Refintegration is therefore equivalent to the reference voltage V2 We then enter the integration phase where the response of the integrator must be calculated.

[0047] In the case where the voltage V is lower than the variable "Reintegration" the program triggers either the use of a normal integration constant in the calculation performed, or the use of a weighting for the integration constant. This weighting as represented in the PI frame is used if the voltage is lower than a second comparison variable called "FastThreshold" which allows to define a voltage threshold from which the variable "weighting" (defined above) is used in the calculation of the variation of the voltage or not. For example, and in a non-limiting manner, the variation of the voltage has a general form of type x = (slope * global V + ordinate) * weighting.

[0048] If the difference or variation of the input voltage V, dV, between an instant t1 and an instant t2 (or between two successive measurements of the voltage V), defined by dV = |V(t2)-V(t1)|, is greater than the variable "SeuilRapide", the variable "weighting" takes for example the value 5. If, on the contrary, the said difference or variation of the voltage V, dV, is less than the variable "SeuilRapide", the variable "weighting" takes the value 1. This corresponds to using a normal integration constant.

[0049] The voltage measurement time step can be understood, for example and in a non-limiting manner, between 1 ms and 100 ms. The value of the variable "FastThreshold" can be defined according to the measurement time step and by monitoring the voltage variation between two instants t1 and t2, corresponding to said time step, used to carry out the voltage measurements, in order to improve the conditions for detecting abnormal conditions. For example, and in a non-limiting manner, for Figure 4B, the measurement time step used is 10 ms and the value of "FastThreshold" is 0.01 Volt. This corresponds to a voltage drop dV = 0.01 Volt every 10 ms.

[0050] The variables "Ordinate", "Slope", obtained by memorizing the measurement points and calculation, for example by a fit of the memorized voltage data or by the use of two points of the voltage curve memorized between two times t1 and t2 to deduce the "slope" (for a linear variation of the voltage) then the "ordinate", allow to define the voltage variation. In the example where x = (-0.25 * Vglobale + 2.5) * weighting, the slope is -0.25 and the ordinate 2.5.

[0051] The step of comparing the voltage variation dV is equivalent to a step of comparing the calculated slope with the stored “Rapid Threshold” value, either to apply, in the event of the slope exceeding the “Rapid Threshold” value, a weighting coefficient (for example 5) increasing the acceleration of the evolution of the integral so that it crosses the trigger voltage threshold Td more quickly, or in the event of not exceeding a weighting coefficient without acceleration effect (for example 1).

[0052] Once the voltage variation is obtained, the signal is integrated according to the second progression equation, for example. The output signal thus corresponds to the integration of the input signal.

[0053] The variable “Progressivity Coefficient” corresponds to an integration constant (Rate in the second progressivity equation).

[0054] In the embodiment, by digital integrator, the person skilled in the art will understand that the assembly using the comparators U1 and U2 is replaced by a microprocessor playing the role of a digital comparator (Un). Said microprocessor is equipped with a storage memory allowing the memorization of the threshold variables "Refintegration" and "FastThreshold" and the calculation variables "Ordinate", "Slope" defined according to these thresholds. The memory also contains the calculation program allowing the collection of the voltage curve points (Vglobale, ...), the comparisons and decisions, the implementation of the equations, the integration and the decisions represented in the logic diagram of the figure 12 .

[0055] The digital circuit receives only as input the voltage Vglobale coming from the common point of a divider bridge between a resistor R1 and a resistor R2 and carries out measurements according to a determined frequency to observe the voltage curve Vglobale, then from the detection of the crossing of the threshold "Reintegration" which, on the example of the figure 10 is chosen lower than 3 Volts per cell element or 12 volts for a battery of 4 cell elements in series from this Reference voltage V2 the microprocessor program, triggers the calculations to obtain the comparison with the variable "Rapid threshold" of the variation dV of the global voltage V between two successive instants t1 and t2 (or between two successive measurements), in order to determine the use or not of a variable "Weighting". Thus in the case of a start-up causing a significant drop in voltage from 14 to almost 6 Volts, the "rapid threshold" value being for example, and in a non-limiting manner, fixed at 0.01 volt in the example of the figure 10 , the fast threshold will be crossed and the integration will be done with a weighting to avoid a cut-off that is too fast preventing the start. On the diagram of the figure 10 it can be observed that the battery voltage having dropped rapidly to almost 6 Volts and remaining constant for approximately 18 seconds, the digital circuit integrates the constant value into a straight line which remains below the detection or trigger voltage Td which is chosen at 1 Volt. The response of the integrator or output voltage can be, for example and in a non-limiting manner, obtained with a program such as that defined in the appendix to this application where the variable "tensionGenerale" corresponds to the voltage Vglobale at a time t1 = t and the variable "LastTensionGenerale" represents the value of the voltage Vglobale at time t2 = t-1. The variable "ORDONNEE_ORIGINE" corresponds to the variable "Ordonnée" defined above and the variable "lastIntegratedValue" corresponds to the integral calculation or the response of the integrator.

[0056] The calculation of the integral or the response of the integrator may include taking into account the “Slope and / or Ordinate” variables calculated by the microprocessor from the data of the recorded Vglobal voltage curve.

[0057] Integration is triggered as soon as the overall voltage Vglobale falls below V2= Refintegration= 9 Volts.

[0058] Then during its use the battery voltage drops suddenly from 14 Volts to about 9 Volts then slowly decreases over time along a straight line to 6 volts. The ordinate of the line is about 2.3 volts and the slope is lower than previously and the variation dV of the voltage between two successive measurements can be greater (depending on the value of the slope) than the "fast threshold" variable (for example 0.01 volt in the example shown figure 10 ).

[0059] When the output value of the integration reaches the threshold corresponding to the detection or trigger voltage Td of 1 volt, the cut-off is triggered.

[0060] Finally, in the digital version or variant, during a short circuit, the global voltage V drops very quickly to a very low value, a short circuit detection threshold is stored and as soon as the processor detects that this threshold has been crossed, it activates the circuit breaker trigger signal.

[0061] In the figure 10 illustrating the response or output signal of a digital integrator according to the example described above, the digital integrator exhibits behavior that is similar to that of an analog integrator ( figure 11 ) in the time interval between t=40s and approximately t=120 s.

[0062] In the trip phase, the response calculation is used to check whether a trip should be triggered (or activated) or not. The trip is activated when the integrator response is greater than a given threshold corresponding to the detection or trigger voltage Td. In the example above, illustrated by the figures 10 , 11 , 12 , this threshold is set at approximately 1 or 1.24 Volts. For example, and without limitation, the threshold value can be normalized to 1.

[0063] Below is presented a non-limiting example of a digital integrator program to implement the integrator response of the figure 10 :

[0064] Thus the BMS comprises at least one detection device (2) for deep discharges, overcurrent and short circuit in each unit element or modular assembly of the battery and comprises at least one BMS device; the BMS being characterized in that the detection device is unique and comprises a comparator U1 which directly compares a proportional voltage, in a determined ratio, to that of the unit element or of the modular assembly, without using a resistive shunt, to compare it to a reference voltage V2 to activate or not the disconnection of the battery (4) according to the variations in the voltage of the unit element or of the modular assembly, the proportion ratio between the measured voltage and that of reference corresponds to the ratio between the reference voltage V2 and the trigger voltage Td from which the disconnection device is actuated.

[0065] In a variant of the BMS, a microprocessor equipped with at least one storage memory allowing the storage of at least one threshold variable “Refintegration” and a stored detection voltage value Td, the memory also containing the program executed by the microprocessor allowing the collection of the voltage curve points Vglobale, the comparisons of the voltages Vglobale with “refintegration” and of the calculated voltage integral (Vinteg) with Td and decisions, the implementation of the equations allowing the integration, the microprocessor receiving as input the voltage Vglobale coming from the common point of a resistor divider bridge connected between the two poles of the cell or of the set of cells and stores the measurements according to a determined frequency to observe the voltage curve Vglobale, and compare the values ​​of the voltage curve Vglobale with the “Refintegration” value,then from the detection of the crossing of the “Refintegration” threshold, defined by the value stored in the memory, triggers the integration calculations of the Vglobal curve and compares the values ​​of the integration curve (Vinteg) calculated with a stored detection voltage value Td to activate the circuit breaker device carrying out the cut.,

[0066] According to a variant, the memory also includes the value of a variable "RapidThreshold" stored to determine by comparison of the instantaneous voltage Vglobal with the "RapidThreshold" whether the calculation of the integral of the voltage curve Vglobal must take into account or not a weighting coefficient.

[0067] According to another variant, the calculation of the integral can take into account “Slope and / or Ordinate” variables calculated by the microprocessor from the data of the recorded Vglobal voltage curve.

[0068] In some embodiments, the detection circuit includes one or more of the following features: Balancing of the cell voltage, Detection of too low voltage and opening of the circuit Detection, by a voltage measurement circuit, of short circuit, deep discharge and overcurrent to trigger the disconnection of a group of cells by opening the circuit Detection of too high voltage of one of the battery cells and opening of the circuit

[0069] In some embodiments, voltage balancing is achieved by a diode "OR" function connecting each of the cells connected in parallel with the negative polarity of the divider bridge of the short-circuit, deep discharge and overcurrent voltage measurement circuit.

[0070] In some embodiments, each cellular element of a line is connected to each adjacent cellular element of another line by an element constituting a thermal fuse, preferably resettable.

[0071] In some embodiments, the detection circuit includes the following functionalities: integrates temperature monitoring which remains constantly active, even if the battery is "off", by analyzing the temperature in the battery casing, measured by a probe mounted on the central part 13 of the cards of each module.

[0072] In some embodiments, the electronic components of the current limiting circuit breaker device to the load, preferably only to the load, for regulating the load current include a component such as a resistor, which is conductive in one direction, and resistive, such as a diode connected in opposition, in the other direction.

[0073] In some embodiments, the circuit is arranged so that the charging and discharging cut-off members are controlled independently.

[0074] The invention also relates to a high-current, semi-modular, series and parallel battery pack consisting of lithium accumulator cells of the same characteristics connected in series to form a line by connections in a given direction S corresponding to the direction of the high currents to obtain the necessary voltage, and intended to be able to be associated in parallel with another line of accumulator cells, said pack using a management system as described in the present disclosure and characterized in that: a pair of upper 71 and lower 72 bezels which delimit a set of cylindrical housings with a square or polygonal or circular section defining, in the same direction S, at least one line of cylindrical housings with a square or polygonal section, each holding a lithium accumulator cell; the connections between the accumulator cells of the same line in the direction S are ensured by wide tabs (9) connecting on each upper or lower face of the module each pair of adjacent cells mounted in series by their poles of opposite polarity in the first direction S, the connection tabs of one face being offset by one cell on the other face;the bezels comprise at least two rows of housings parallel to the direction S in which at least two rows of cells are arranged in a direction perpendicular to S and connected to each other either by thin tabs acting as a fuse or by resettable fuses (F, ; fig.2 ), along the direction perpendicular P to the direction S, each fuse connecting two cells belonging to two different parallel lines to make a parallel connection between each cell of two parallel sets of series cells.

[0075] In some embodiments, the circuit is arranged so that the charging and discharging cut-off members are controlled independently.

[0076] In certain embodiments, the bezels hold by the sides at the upper part 71 and lower part 72 of the PCB (printed circuit board) cards in printed circuit comprising the electronics and the electrical connections between the components of the electronics of the management system and the cells of the semi-modular block; intercalated PCBs (12,13, fig 1 ) are arranged vertically between the cells in a direction perpendicular to the direction S comprise at least the heating resistors of the semi-modular assembly and these resistors are connected on command of the management circuit to a power supply; the PCB part arranged under the cells contributes to the recovery of the potentials of each of the cells of the modular block to supply them to the voltage management and balancing circuit of the modular block management system.

[0077] It is understood that by "cellular element", "cell" or "accumulator", we mean any unitary system configured to store electrical energy in a different form, here preferably by electrochemistry using Lithium-ion technology.

[0078] In some embodiments, resistors are mounted between two contact pads (not shown) on the upper and / or lower PCB boards and contact with the cells and the tracks of the upper or lower printed circuit board is made by elastic pins (Pogo, or conical helical springs, for example) arranged between the cells and the conductive face comprising the contact pads of the printed circuit board, thus avoiding the use of tin solder.

[0079] Advantageously, the present invention makes it possible to increase the current by adding batteries in parallel rather than in series without balancing problems, and without the need to resize the constituent elements of the circuit (increase the capacity of the accumulators and the sizes of the transistors (cut-off devices). The transistor cut-off device, in the context of this solution, is adapted to the line current, which allows easy balancing. Indeed, in certain solutions, such as TrueBlue Power, blocks of cellular elements in parallel are arranged in series one after the other with a single cut-off device composed of a certain number of MOSFEts arranged in parallel with each other, so that the current is not balanced. Indeed, the balance of the currents of diodes or cut-off devices in parallel is almost impossible to achieve, because the forward voltage decreases sharply with temperature.Thus, the hottest element supports all the current, which further increases its temperature until destruction. Thus, if one of the switching devices heats up more, it will receive more current and heat up more by avalanche effect, which must be avoided at all costs. Conversely, the present invention makes it possible to increase the current and the capacity without theoretical limit, because the current distribution is the same in all the switching devices, which therefore do not need to be oversized.

[0080] In other words, by duplicating the elements in parallel it is important to ensure the proper functioning of the assembly and in particular the monitoring of all the cells. The greater the number of blocks in parallel, the greater the number of connections between the cells and the boards. The use of "pogo pins" (elastic pins) or conical helical springs limits the number of solderings while ensuring easy assembly by the bezels which hold the cells and the PCB boards on which one end of each elastic pin is mechanically secured to the PCB and electrically to the connecting conductor. The other end of the pin comes into contact with a pole of the cell corresponding to the location of the pogo pin.

[0081] Furthermore, the present invention proposes a cut-off member per line of cellular elements in order to be able to cut only partially the circuit and thus allow, at least momentarily, the safe use of the battery despite the occurrence of a problem (short circuit, overload or deep discharge). We then observe a maintenance of the voltage with a lower available current.

[0082] Preferably, only one cut-off device is present per row of batteries in series. In some embodiments, the overall voltage per row of cells and the voltage of each cell is monitored by the BMS.

[0083] In some embodiments, the vertical central board (13) includes temperature probes and a thermostat.

[0084] Thus, in certain embodiments, the card (5) comprising the management system (BMS) is arranged vertically on the side of the battery pack so as to form a U with the other PCBs of said pack.

[0085] In some embodiments, the vertical center board includes temperature probes and a thermostat.

[0086] Advantageously, the use of an optocoupler allows, among other things, communication between different PCBs.

[0087] An exemplary method for forming a battery pack according to certain embodiments as described above comprises the following steps: pre-welding of blocks (2) (4 by 1 or 8 by 1) of accumulators (20) in series by the tabs (9), installation of the blocks on the lower bezel (72) and on the lower PCB (6), Installation of the upper bezel (71) and the upper PCB (4, 4'), Riveting of the accumulators on the power bar of the upper PCB (4) [and riveting of the upper PCB (4) to the upper bezel (71), which allows easier, faster assembly with additional reliability and safety.

[0088] “The contact between the cells (20) and the conductor tracks connecting the cells to the components are made by the elastic pins (10) or conical helical springs.

[0089] In certain embodiments, as for example illustrated in a non-limiting manner in the figure 1 functionally, a BMS (Battery Management System) is configured to measure the voltage and current across the various cellular elements and the overall voltage of each line, and measure the temperature at these cellular elements and / or lines. Depending on the measured temperature, the BMS (3) can send a signal to heaters configured to heat the cellular elements in order to maintain them at the optimal operating temperature. When the BMS measures a voltage or a current exceeding predetermined threshold values, corresponding for example to a slow or deep discharge, an overload or a short circuit, it is configured to send a cut-off command to the cut-off device associated with the line of accumulators comprising the faulty cellular element. This thus makes it possible to cut a line without cutting the entire circuit.This makes it possible, in particular, to continue operating the battery, in a "degraded" mode allowing the element using the battery, for example an aircraft, to continue operating, at least for a certain time, without damaging the battery, until the battery can be safely deactivated and repaired.

[0090] Advantageously, such a configuration allows the design of a simplified circuit, with a single - terminal and a single + terminal, rather than two + terminals, depending on the use of the battery (charging or discharging) as is the case in certain prior arts.

[0091] More specifically, the figure 2 illustrates an exemplary and non-limiting embodiment of the present invention, in which resettable fuses are installed between the different inter-battery potentials. This circuit is preferably arranged on the upper PBC (see figure 5 à 7 ). This allows to isolate a defective accumulator (in short circuit), because otherwise this accumulator would cause significant currents and could lead to destruction of the battery. With diodes are realized "or" functions of all the accumulator lines by potential, so for a battery of for example 12 V we obtain 4 potentials for the low voltage and 4 potentials for the high voltage. This voltage is then compared to a predetermined threshold and a cut-off is made in case of exceeding these thresholds. There is an undervoltage circuit and an overvoltage circuit whose detections are merged by measurement at the terminals of each accumulator and are concatenated using diodes.

[0092] The supply voltage of the under / over voltage and balancing blocks are carried out directly at the terminals of the accumulator, we obtain a circuit supplied between 0-4V (0-4V, 4V-8V, 8V-12V, 12V-16V), which poses a problem for recovering the output information. Therefore, an adaptation stage is required in order to carry out a level translation. The output of the comparators is coupled with a pulse transformer by oscillating a hysteresis logic gate.

[0093] THE figures 3 et 4 represent the circuit of the cut-off device in a simplified way: certain elements are not represented (respectively the components linked to M2 in the figure 3 and M1-related components in the figure 4 ) in order to simplify the reading of said figures.

[0094] MOSFET transistors are used for the switching devices. This advantageously makes it possible to obtain switching devices with very low static consumption in both the on and off states. figure 3 details in a non-limiting manner an example of MOSFET-based discharge cut-off. V1 is the battery and L1 - R5 is the load (e.g. the starter). Diode D4 is conductive during discharge. It must withstand the short-circuit current for at least 10 ms, and dissipate Joule losses during a high-current discharge. The short-circuit current is estimated at 264 A for an 8S1P assembly of A123 Systems elements. Cut-off during a short circuit or at the end of discharge is provided by MOSFET M1, which must also withstand the short-circuit current for at least 10 ms. V2 is the voltage source that drives M1 (from the detection circuit). Ideally, this source delivers 6 to 10 V so that M1 is conductive. Zener diode D3 and capacitor C2 protect the MOSFET gate from excessively high or high-frequency voltages.

[0095] When M1 opens, an overvoltage greater than the Vds of M1 may occur due to the cancellation of the current in the inductor L1. D1 is a zener diode which, together with the resistor R3 and the diode D2, limit the switching speed of the MOSFET M1.

[0096] The R1 - C1 (resistor - capacitor) assembly is located at the + and - terminals of the battery and also helps to limit the overvoltage when M1 opens.

[0097] By way of example and without limitation, the figure 4 presents in a non-limiting manner an example of a circuit included in an embodiment of the invention allowing the limitation of the charging current, as well as the cut-off at the load. V4 - R5 is the alternator of the device or a charger. It supplies 28 V in normal operation, but can deliver a higher voltage in the event of a fault in its regulator. Standardized tests give a voltage of 1.5 times the nominal voltage of the battery, i.e. 42 V. In practice, it is possible for this voltage to reach 80 V. The limitation of the charging current is ensured by a diode D4 passing in the discharge direction, and blocked in the recharge direction, in parallel with a current limiting resistor I1.

[0098] Thus, diode D4 must withstand the short-circuit current. This is achievable for a modular battery, but very difficult for a high-capacity battery. Indeed, a non-modular 17 Ah battery, for example, can provide a short-circuit current of more than 2000 A. Therefore, the diode should be able to withstand this current. Diodes capable of withstanding this current do not exist as "electronic components," and in practice, several lower-current components can be connected in parallel. But balancing the diode currents in parallel is almost impossible to achieve, because the forward voltage decreases sharply with temperature. Thus, the hottest diode withstands all the current, which further increases its temperature until it is destroyed.

[0099] MOSFET M1 is configured at its gate to always be on in the charging phase. Diode D4 is blocked during charging, and the charging current passes through I1 and M2. I1 is a power resistor for limiting the charging current. In other equivalent embodiments, I1 can also be a combination of resistors and polyswitches, or a semiconductor current regulator. MOSFET M2 is on when its gate-source voltage, Vgs, is at 10 V for example. D6 is an 18 V zener diode for example, and D5 a 10 V zener diode. Thus, at a voltage of 28 V (alternator voltage), D6 and D5 are at the limit of conduction, there is no current in R6 and Vgs = 10 V and the charging current passes through I1 and M2. The voltage values ​​of diodes D5 and D6 therefore make it possible to define the value of the gate-source voltage of MOSFET M2. Capacitor C5 protects the gate of MOSFET M2 from high-frequency voltages.

[0100] Detecting a charger fault involves two measurements: measuring the voltage of each cell, and measuring the overall voltage. If the voltage of a cell exceeds, for example, 4 V or if the overall voltage exceeds, for example, 32 V, then the charging cut-off device is activated. Charging is possible again when the voltage has dropped below 26 V, for example, thanks to a hysteresis comparator.

[0101] In the digital variant, the microprocessor will be wired with the battery to receive on its inputs both a voltage representative of the voltage of each cellular element Vcec constituting the battery and also the overall voltage measurement Vglobale of the battery, available on the conductors leading to the external terminals of the battery. The program executable by the microprocessor will include a code module monitoring these two voltages Vcec and Vglobale to, after comparing each with a respective determined stored threshold, trigger the cut-off by activating the circuit breaker element (31), when this threshold is exceeded.

[0102] Concerning the triggering of the load cut-off device, in the event of a voltage or temperature exceedance of a unit element, the blocking of M2 is done thanks to the optocoupler U1. Indeed, the optocoupler U1 includes an LED (Light Emitting Diode) and a transistor. Thus, in the event of a voltage or temperature exceedance of a unit element, a current flows in the LED and makes the transistor conduct. The gate-source voltage, Vgs, of the MOSFET M2 is brought close to 0 V (Vcesat for collector-emitter voltage at saturation of U1). M2 then cuts the load current (D4 and M2 are blocked). The current in the LED of U1 is taken at the common point between M1 and the battery, therefore on the battery voltage due to the disconnection between the 0V of the battery and the 0 V of the alternator or charger.

[0103] Concerning the triggering of the load cut-off device, in the event of an element voltage or temperature exceeding, the blocking of M2 is done thanks to the optocoupler U1: a current in its LED makes the transistor conduct, thus the Vgs of the MOSFET is brought close to 0 V (Vce sat of U1). M2 then cuts the load current (D4 and M2 are blocked). The current in the LED of U1 is taken from the battery voltage due to the disconnection between the 0V of the battery and the 0 V of the alternator.

[0104] The solutions proposed so far describe external modular architectures where several batteries are coupled to an external data bus allowing information to be sent to a supervisor.

[0105] The architecture proposed by the invention is on the contrary internal to the battery, and can be a modular architecture as represented by way of example and in a non-limiting manner in the figure 5 . This figure thus presents a schematic view of the battery comprising several rows of accumulators, fixed by PCBs to form a "U". More precisely, a battery pack according to certain embodiments as illustrated comprises a plurality of blocks of cellular elements in series (preferably 4 by 1 or 8 by 1), the blocks being framed at their two longitudinal ends by upper and lower bezels. At their upper end, the accumulator blocks are coupled to a PCB board, called "top PCB", for example at holes in the PCB board configured specifically to accommodate said end of the blocks. Rivets make it possible to fix the top PCB board to the upper bezels. This assembly forms the upper face of the battery pack. The same couplings and fixings are made with a bottom PCB on the opposite face of the battery pack, called the lower face.On a third side of the battery pack is fixed a third printed circuit (middle PCB), also fixed to the top and bottom bezels, so as to form a "U" with the top and bottom PCBs. In addition, although not shown on the . figure 5 à 7 , interposed PCBs are arranged vertically between the cells in a direction perpendicular to the direction S and comprise the heating resistors (heaters) of the semi-modular assembly, and these resistors are connected on command from the management circuit to a power supply to cause said heating.

[0106] In certain embodiments, a pair of upper 71 and lower 81 bezels delimits a set of cylindrical housings with a square or polygonal or circular section defining, along the same direction S, at least one line of cylindrical housings with a square or polygonal section, each holding a lithium accumulator cell.

[0107] In some embodiments, the PCB boards held to the upper and lower bezels include the electronics and electrical connections between the electronics components of the management system and the cells of the semi-modular block.

[0108] The bezels comprise at least two rows of housings parallel to the direction S in which at least two rows of cells are arranged in a direction perpendicular to S and connected to each other by thin tabs, in the direction perpendicular P to the direction S, each thin tab connecting two wide tabs of cells belonging to two different parallel rows to make a parallel connection of two parallel sets of series cells. The wide tabs are preferably made by elastic pins (Pogo pin, or conical helical springs for example) arranged between the wide tabs placed on the cells and the conductive face comprising the contact pads of the printed circuit board, thus avoiding the use of tin solder.

[0109] By way of example and without limitation, the figure 6 shows a front sectional view of the battery along the XX' axis passing through a line of accumulators while the figure 7 presents a schematic view in longitudinal section passing through said axis XX' [passing through a line of accumulators?]. A cut-off member (11) is coupled to each line of cellular elements in series, as illustrated in figure 7 The ends of the cellular elements (20) are thus inserted into the housings of the upper and lower bezels (71, 72). Thin tabs (9) make it possible to connect two lines of cellular elements (20) together.

[0110] By way of example and without limitation, the figure 8 schematically presents the circuit of the top (4,4') and bottom (6) PCB boards of the battery pack. The PCB part 4 is connected on the one hand to each parallel cell of each end of series line (here four series lines) and on the other hand by the power conductor (16) (high current) to the output terminal of the battery. This board 4 includes the cut-off devices referenced by their MOSFETs M3 to M10 which correspond in pairs M3, M4; M5, M6; M7, M8; M9, M10; to each of the cut-off devices 11 shown schematically fig.1 . It should be understood that each element M3, M4 of a pair represents, respectively, in a simplified way the electronic diagram of the figure 3 for each reference M3, M5, M7, M9 of the figure 8 and the electronic diagram of the figure 4 for each reference M4, M6, M8, M10 of the figure 8 .

[0111] Additionally, the battery pack and system may include various features to enhance their usability and reliability.

[0112] Thus, the present invention may include a communication card making it possible to recover the different quantities of the analog sensors, to store them in a log, to calculate certain parameters such as state of health, charge (SOH and SOC). It preferably includes a CAN link (standard protocol in the automotive and aeronautical industries), a LIN link, and possibly an LCD screen for the HMI (Human-Machine Interface).

[0113] The battery pack incorporates a power off / on function. This function allows for safe storage of the battery and maintenance operations. The user can also turn off the battery pack when not in use to prevent untimely discharge of the battery and the risk of fire due to a malfunctioning instrument.

[0114] Heaters are preferably manufactured by wrapping copper around an inner layer of a PCB. This allows for a simple and inexpensive production method. This technique allows for the integration of connectors.

[0115] Preferably, the block does not include tin soldering during assembly. This makes it possible to provide a system that does not include all the wires of certain prior art devices. Connectors are thus placed on the heaters, on the bezels and on the top and bottom distribution PCBs.

[0116] The BMS then connects to all these connectors, using a mechanical attachment to avoid the risk of disconnecting a connector during vibrations during use.

[0117] Unlike some prior art batteries, the system of the present invention has only one active operating mode for all the safety features provided by the BMS, and has no standby mode. This is made possible by the use of very low consumption components. Indeed, thanks to the low standby current of for example approximately 80 µAmps, the safety features of the battery's BMS can remain permanently powered without penalizing the maximum storage duration.

[0118] The battery pack of the present invention has very good resistance to shocks and vibrations. Indeed, it is mechanically separated into two parts: an external part secured to the casing, an internal part including the accumulator cells. The two parts are preferably mechanically decoupled by a flexible material which improves the shock and vibration resistance of the battery. The front panel, the user interfaces and the BMS electronic card are secured to the casing. The accumulator cells, the spacers, the heaters, the electromechanical relay and the "distribution card" form the mechanically decoupled internal part. All electrical connections between the internal part and the external part have a certain flexibility in the three directions of space (axes x, y, z).

[0119] Good thermal insulation allows for better efficiency of the electric heater: lower electrical consumption to bring the elements to their ideal operating temperature. Thermal insulation also makes it possible to reduce the temperature differences experienced by the accumulator cells in the case of an aircraft which alternates periods on the ground at high temperature (for example: +30°C) and periods in flight at very low temperature (for example: -10°C). This may be the case for devices for dropping parachutists. The battery of the present invention may, for example, use aeronautical-grade flame-retardant cork. The advantage of this material is that it provides the function of thermal insulation, thermal protection and mechanical decoupling. Thermal protection and thermal insulation also act as electrical insulation between the live parts internal to the battery and the metal casing.Because there are two insulating materials, the battery of the present invention inherently has double electrical insulation between the live parts and the casing. This arrangement minimizes the risk of internal short circuit in the event of a violent shock (shock amplitude greater than standard tests). This material is very resistant to wear caused by vibrations (fretting corrosion).

[0120] It appears from reading the characteristics described above that the system proposed by the present invention has the following advantages: A single device simultaneously provides short-circuit, overcurrent, and deep discharge protection. Overcurrent detection and shutdown without current measurement. Disconnection current automatically adapted to the characteristics of the battery cells. No shunt, no magnetic sensor, no heating element. Disconnection curve similar to a magnetothermal curve. The disconnection curve follows the aging of the battery cells. Robust charging current limitation, without the need for current measurement. Ordinary power components (SMD components) due to modularity and reasonable currents. Current balance in the power components. Monitoring of the various quantities by microcontroller. Communication on a standard data bus, LCD display. No fine tuning required. Very low static consumption. Circuits always active, no "active" and "standby" modes.Very high level of operational safety (high MTBF). Use of standard, non-strategic and non-specific components for BMS use.

[0121] It will be readily understood from a reading of this application that the features of the present invention, as generally described and illustrated in the figures, may be arranged and designed in a wide variety of different configurations. Thus, the description of the present invention and the related figures are not intended to limit the scope of the invention but merely represent selected embodiments.

[0122] Those skilled in the art will understand that the technical features of a given embodiment may in fact be combined with features of another embodiment unless the opposite is explicitly stated or it is obvious that these features are incompatible. Furthermore, the technical features described in a given embodiment may be isolated from the other features of this embodiment unless the opposite is explicitly stated.

[0123] It should be obvious to those skilled in the art that the present invention allows embodiments in many other specific forms without departing from the field defined by the scope of the appended claims, they should be considered by way of illustration and the invention should not be limited to the details given above. LISTE DES SIGNES DE REFERENCE

[0124] 1. Battery pack 2. Cell block in series 20. Cell elements 3. BMS system 4. 4'. Top PCB (distribution) 5. Middle PCB (BMS) 6. Bottom PCB (distribution) 71. Lower bezel 72. Upper bezel 8. Rivets 9. Tab (thin) 10. Pogo pin 11. Cut-off device 12. Heater 13. Thermostat / T°C sensor 14. Balancer 15. Over / under voltage 16. Power conductor (high current) to the positive terminal 17. Power conductor (high current) to the negative terminal 31. Circuit connection between the BMS and the cut-off devices F. Fuses

Claims

1. Battery management system (BMS, 3) for accumulators of a semi-modular element comprising a plurality of lithium cell elements (20) connected in series to form a line, said battery management system for accumulators comprising at least two serial lines connected in parallel constituting the semi-modular element, and at least one detection circuit, said detection circuit comprising at least one discharge or short-circuit detection device and at least one device for monitoring the voltage and temperature of at least one of cells elements, said battery management system (BMS, 3) for accumulators comprising a circuit breaker device, said detection circuit controlling said circuit breaker device comprising at least one switching device (11) per line, preferably only one per line, and connected on the one hand to the negative or positive pole of each set of cell elements (20) or each battery and on the other hand to the positive or negative terminal, respectively, of the battery, the switching device (11) comprising, for each line, a load breaking device, a discharge breaking device, and electronic components limiting the current at the load, preferably only at the load, and said load breaking device comprising at least two, preferably only two, MOSFETs (M1, M2) per line; a first MOSFET (M1) performing a circuit break in the event of discharge below a threshold or during a short circuit, a second MOSFET (M2) performing a load break in the event of voltage or temperature overshoot of an element of said circuit, the electronic components such as a set of diodes, resistors, capacitors, for example around the second MOSFET (M2), performing a current limitation at the load.

2. Battery management system (BMS, 3) for accumulators of a semi-modular element according to claim 1, characterized in that the first MOSFET (M1) is connected by its source to the negative terminal of a set of cells, this first MOSFET (M1) receives, on its gate, a voltage source (V2) that drives (M1), this source delivering a chosen voltage (for example 6 to 10 V) so that the first MOSFET (M1) is on, a Zener diode (D3) is connected in opposition between the gate and the source of the first MOSFET (M1) and a capacitor (C2) protect the gate of the first MOSFET (M1) from excessively high or high-frequency voltages, and a Zener diode (D1) mounted in opposition between the gate of the first MOSFET (M1) and the drain and in series with a resistor (R3) and a diode (D2) in the forward direction in the drain-to-gate direction, (D1, D2, R3) limiting the switching speed of the first MOSFET (M1) and a circuit consisting of a Schottky diode (D4) limits the load current, this Schottky diode (D4) is mounted in opposition on the drain of the first MOSFET (M1) in the charging direction, and in series with a capacitor C1 and a resistor R1 connected to the positive terminal of the battery to also limit the overvoltage when opening the first MOSFET M1, in parallel on the Schottky diode (D4) a fixed resistor I1 is mounted that is connected on the one hand to the cathode of the diode and on the other hand to the drain of the second MOSFET (M2) whose source is connected to the anode of the Schottky diode (D4), the gate of the second MOSFET (M2) being controlled by an output of the detection circuit to prevent the load.

3. Battery management system (BMS, 3) for accumulators of a semi-modular element according to claim 1, characterized in that the second MOSFET (M2) is connected by its gate to the base of the phototransistor of an optocoupler whose emitter is connected to the source of M2; between these two points, a Zener diode (D5) and a capacitor (C5) are connected by the BMS card; the light-emitting diode of the optocoupler is connected by its cathode to the negative terminal of the battery or of the modular set of cells and receives, on its anode, the command sending a current into the LED in case of detected voltage or temperature overshoot of an element.

4. Battery management system (BMS, 3) for accumulators of a semi-modular element according to claim 1, characterized in that the arrangement of the disconnection circuit associated with the two MOSFETs is interposed between the output pole of a line and the same terminal, of the same polarity (positive or negative), of the battery.

5. Battery management system (BMS, 3) for accumulators of a semi-modular element according to claim 1, characterized in that the BMS is connected to and controls each cell element (20) and each accumulator line of the circuit and monitors the voltage of each cell and each serial line of cells.

6. Battery management system (BMS, 3) for accumulators of a semi-modular element according to one of the preceding claims, wherein the detection circuit comprises one or more of the following functionalities: Cell voltage balancing; Detection of excessively low voltage and open circuit Detection, by a voltage measurement circuit, of short-circuit, deep discharge and overcurrent to trigger the disconnection of a group of cells by opening the circuit Detection of excessively high voltage of one of the battery cells and opening of the circuit.

7. Battery management system (BMS, 3) for accumulators of a semi-modular element according to claim 4, characterized in that the voltage balancing is performed by a diode OR function connecting each of the cells connected in parallel with the negative polarity of the divider bridge of the short-circuit, deep discharge and overcurrent voltage measurement circuit.

8. Battery management system (BMS, 3) for accumulators of a semi-modular element according to claim 4, characterized in that each cell element of a line is connected to each adjacent cell element of another line by an element constituting a thermal fuse (F), preferably resettable.

9. Battery management system (BMS, 3) for accumulators of a semi-modular element according to claim 1 or 4, characterized in that the detection circuit comprises the following functionalities: integrates temperature monitoring that remains constantly active, even if the battery is "off, by analyzing the temperature in the battery envelope, measured by a probe (13) mounted on the central part of the cards of each module.

10. Battery management system (BMS, 3) for accumulators of a semi-modular element according to claim 1, characterized in that the electronic components of the circuit breaker device limiting the current to the load, preferably only to the load, for regulating the load current comprise a component such as a resistor, which is conductive in one direction, and resistive, like a diode connected in opposition, in the other direction.

11. Battery management system (BMS, 3) for accumulators of a semi-modular element according to claim 1, characterized in that the circuit is arranged in such a way that the charging and discharging switching devices are controlled independently.

12. High-current, semi-modular, series and parallel battery pack (1) consisting of lithium accumulator cells of the same characteristics connected in series to form a line by connections in a given direction S corresponding to the direction of the high currents to obtain the necessary voltage, and intended to be able to be associated in parallel with another line of accumulator cells, said pack comprising a management system (3) according to one of the preceding claims, and characterized in that: a pair of upper (71) and lower (72) bezels that delimit a set of cylindrical housings with a square or polygonal or circular section defining, in the same direction S, at least one line of cylindrical housings with a square or polygonal section each holding a lithium accumulator cell; the connections between the accumulator cells of the same line in the direction S are ensured by wide tongues (9) connecting, on each upper or lower face of the module, each pair of adjacent cells connected in series by their poles of opposite polarity in the first direction S, the connecting tongues (9) on one face being offset by one cell on the other face; the bezels (71, 72) comprise at least two lines of housings parallel to the direction S in which at least two lines of cells are arranged in a direction perpendicular to S and interconnected either by thin tongues acting as a fuse or by resettable fuses (F, Fig. 2), in the direction P perpendicular to the direction S, each fuse (F) connecting two cells belonging to two different parallel lines to make a parallel connection between each cell of two parallel sets of serial cells.

13. High-current battery pack (1) according to claim 12, characterized in that the bezels hold PCBs (printed circuit boards) by the sides at the upper (71) and lower (72) part, which PCBs comprise the electronics and the electrical connections between the electronic components of the management system and the cells of the semi-modular block; intermediate PCBs (12, 13, Fig. 1) are arranged vertically between the cells in a direction perpendicular to the direction S comprise at least the heating resistors of the semi-modular assembly and these resistors are connected on demand from the management circuit to a power supply; the PCB part (6) arranged under the cells contributes to recovering the potentials of each of the cells of the semi-modular block to supply them to the voltage management and balancing circuit of the semi-modular block management system.

14. High-current battery pack (1) according to claim 12 or 13, characterized in that resistors are mounted between two contact pads (not shown) on the upper (4, 4') and / or lower (6) PCBs and the contact with the cells and the tracks of the upper or lower printed circuit boards are made by elastic pins, or conical coil springs, for example, arranged between the cells and the conductive face comprising the contact pads of the printed circuit board, thus avoiding the use of tin solder.

15. High-current, semi-modular battery pack (1) according to one of claims 12 to 14, characterized in that the vertical central board (13) comprises temperature sensors and a thermostat.

16. High-current, semi-modular battery pack (1) according to one of claims 12 to 15, characterized in that the board (5) comprising the management system (BMS, 3) is arranged vertically on the side of the battery pack (1) so as to form a U with the other PCBs (4, 6) of said pack.