Battery comprising a plurality of cells for storing electrical energy and circuits for monitoring the cells individually

Abstract

The invention relates to a battery (BT) comprising: multiple branches (BRj) connected in parallel between respective positive branch terminals (BTHj) and a negative external battery terminal (PTL), each branch comprising multiple modules (MDk) connected in series, and a battery management unit (BMU) connected to the positive branch terminals and to the external terminals of the battery, each module comprising: multiple sub-branches connected in parallel between respective positive sub-branch terminals and a negative module terminal, each sub-branch comprising multiple cells connected in series, each comprising two connection terminals connected to one respective measurement unit, and a module management unit connected to the positive sub-branch terminals and to the terminals of the module, and comprising a first communication circuit for communicating with the measurement units of the module and a second communication circuit for communicating with the battery management unit.

Description

[0001] DESCRIPTION

[0002] TITLE: Battery comprising a plurality of electrical energy storage cells and individual cell monitoring circuits

[0003] Domain

[0004] The present invention relates to electrical energy storage batteries comprising a plurality of battery cells and communication between different monitoring and processing units within such batteries, in particular to transmit parameters representative of the operating state of the battery and the battery cells.

[0005] The present invention is particularly applicable to electrochemical cell batteries of the lithium-ion, sodium-ion, potassium-ion, magnesium-ion, lithium / sodium metal, or metal-air type, whether with liquid, solid, or gel electrolyte. Such batteries can be used in various applications such as electric vehicles, drones, power tools, and stationary energy storage.

[0006] State of the art

[0007] Electrical energy storage batteries are designed to be connected to a charging circuit to be charged and store electrical energy, and to discharge by producing an electrical current when connected to a load. Battery cells are connected in series and / or parallel within the battery to achieve the required voltage and energy capacity. Typically, a battery with cells, for example, lithium-ion, comprises several identical blocks of individual cells, each block containing one or more cells in parallel. Several identical blocks are connected in series to achieve the desired total battery voltage. The total energy capacity of the battery is determined by the capacity of a single block, which is itself determined by the energy capacity of an individual cell multiplied by the number of identical cells connected in parallel within each block.

[0008] Some batteries, particularly those of the types listed previously, can cause an explosion, combustion, and / or violent outgassing. To guarantee both battery lifespan and safe operation, it is therefore important to be able to monitor, regularly or even continuously, representative functional parameters of the battery's condition, both during operation and at rest. The functional parameters to be monitored may relate to the battery as a whole, or preferably to each group of cells within the battery, or even to each individual cell within the battery. These parameters may include, in particular, temperature and pressure parameters, minimum discharge voltages, and maximum charge voltages. It is also desirable to be able to monitor the electrical balance of all the cells, as well as the evolution of various battery parameters such as voltage and current during charge and discharge cycles.Utilizing these functional parameters allows for the control of the charger's output voltage and current, as well as the management of functions such as balancing and ensuring the battery's thermal safety. This controlled management can also be used to determine the battery's State of Health (SOH), extend its lifespan, and predict its Remaining Useful Life (RUL).

[0009] Generally, controlling battery cells requires a multitude of wires and / or connections between the cells and a central management unit called a "BMS" (Battery Management System). It is therefore understandable that in the case of a complex series / parallel cell assembly, this interconnection with the BMS proves complex, time-consuming, and industrially expensive, especially when the number of interconnected cells is large, as is the case with batteries intended for mobility applications and operating at voltages exceeding 350 volts, requiring a minimum of 100 cells connected in series (depending on the electrochemical pair). Thus, some automotive batteries can contain several thousand cells. The same applies to stationary batteries. The resulting interconnection complexity can represent a source of failure related to the battery's operating conditions.For example, batteries used in mobility applications are subject to vibrations and shocks, which can cause electrical disconnections, making reliable battery operation impossible, or even lead to short circuits or thermal runaways, jeopardizing the integrity of the application due to their inherent danger. The slightest failure of a single cell can thus prevent the entire battery from functioning, particularly in existing battery architectures where several cells or groups of cells are connected in parallel. Indeed, in a parallel cell assembly, if one cell short-circuits, it short-circuits the other cells connected in parallel, resulting in thermal runaway due to the sudden discharge of the other cells into the short-circuited one.

[0010] This interconnection complexity is particularly evident in vehicles where the battery may consist of several units distributed across different locations within the vehicle. This complexity can be reduced by decreasing the number of measurement points, for example, by associating a measurement point with a group of cells rather than with each individual cell. However, this solution requires significant safety margins on the detection thresholds to guarantee the necessary battery operating safety. Indeed, battery cells generally age unevenly (primarily due to variations in internal resistance). This results in behaviors, particularly thermal behavior, that can vary from one cell to another within the same battery.

[0011] It is therefore desirable to be able to measure the functional parameters of each cell in a battery with a very large number of cells, and to be able to transmit these measurements to the battery management unit. To this end, it is desirable to be able to associate each cell with a measuring device integrating sensors for these functional parameters and a communication circuit with the management unit. It is also desirable to avoid having to provide specific connections between the measuring devices associated with the battery cells and the battery management unit. Finally, it is desirable to be able to maintain the battery's functionality as much as possible in the event of cell failure.

[0012] Summary. Embodiments relate to a battery comprising: a plurality of cells, each cell comprising two connection terminals for connecting to other cells and a measuring unit integrated into the cell and connected to the cell connection terminals; several branches connected in parallel between their respective positive branch terminals and an external negative battery terminal; each branch comprising several modules connected in series by their positive and negative module terminals; and a battery management unit connected to the positive branch terminals, to the external positive battery terminals, and to the external negative battery terminal; each module comprising: several branches connected in parallel between their respective positive branch terminals and a negative module terminal; each branch comprising several cells from the plurality of cells, connected in series by their cell connection terminals.and a module management unit connected to the positive terminals of the branch, and to the positive and negative terminals of the module, the module management unit comprising a first communication circuit for communicating with the cell measurement units of the module and a second communication circuit for communicating with the battery management unit.

[0013] Thanks to these features, and in particular the modular arrangement of the cells, all the cells in a battery can be individually monitored by a battery management unit. This avoids the need for as many communication links as there are cells in the battery, prevents overloading the communication circuits of both the cells and the battery management unit, and eliminates the need for excessively long intervals between cell communication. This result can be achieved even when the battery contains several thousand cells.

[0014] According to one embodiment, the management unit of each module and each measurement unit of each module are configured to: emit by the module's management unit a request message in a modulated form by applying pulse bursts in the form of voltage drops between the positive and negative terminals of the branch; receive the request message by each of the module's measurement units, by demodulating the pulse bursts between the terminals of the cell to which the measurement unit is connected; emit by each measurement unit of the module, in response to the request message, a response message in a modulated form by applying pulse bursts in the form of voltage drops between the terminals of the cell to which the measurement unit is connected, during a respective time slot allocated to the measurement unit, the response message containing data from a measurement of an operating parameter of the cell;and receive the response message via the module's management unit, by demodulating the pulse bursts detected at the battery terminals.

[0015] The transmission technique used between the measuring units of each module and the module management unit proves particularly effective for transmitting information between the module management unit and the module's measuring units. Indeed, the transmission of messages via bursts of voltage drops is not attenuated, as these are immediately visible whether emitted by the module management unit or by one of the measuring units. Furthermore, this transmission technique is even more efficient because the messages emitted by the module management unit are received simultaneously by all the module's measuring units. Therefore, it is not necessary for the module management unit to address each measuring unit individually. This transmission technique is thus particularly well-suited to batteries with a large number of cells.Furthermore, each measurement unit can communicate with the module management unit during an allocated time slot. This avoids any risk of collision that can occur when two measurement units of the same module attempt to send a message simultaneously.

[0016] According to one embodiment, each measuring unit is configured to: measure a voltage across the cell terminals, and derive current across the cell terminals through the measuring unit for a balancing time which can be fixed, when the measured voltage is greater than a setpoint value, in order to balance the cell with the other cells of the battery.

[0017] Thus, each battery cell can be individually balanced, allowing the battery to reach its maximum charge level. Furthermore, current bypass at the cell terminals can be achieved using the same components used to communicate with the module management unit.

[0018] According to one embodiment, the voltage drops are applied by the management unit or by each of the measuring units, by controlling a transistor connected to the branch terminals, and respectively to the terminals of each cell.

[0019] Thus, voltage drops can be applied using a very simple circuit, which can easily be miniaturized. Furthermore, by implementing a transistor, the amplitude and width of the voltage drops can be finely adjusted.

[0020] According to one embodiment, the voltage drops generated by each of the measurement units of the module to emit a response message have an amplitude of a few tens of millivolts.

[0021] According to one embodiment, the measurement units are synchronized to a moment of detection of a first voltage drop upon receipt of a request message.

[0022] Thus, the measurement units can easily be synchronized, particularly to avoid collisions when communicating with the management unit.

[0023] According to one embodiment, each module management unit is configured to: detect by the module management unit that one of the battery cells is faulty on the basis of a failure to receive the response message from the cell measurement unit, or on the basis of a cell operating parameter measurement data received in the response message from the cell measurement unit, and if a cell failure is detected, command a switch to disconnect a branch of series-connected cells, to which the faulty cell belongs.

[0024] Thanks to the presence of a measuring unit for each battery cell and switches for each branch, a cell failure can be quickly detected and the battery can be rapidly shut down when a faulty cell is detected. Thus, the entire battery can be protected in the event of a single cell failure, without affecting the battery's voltage output.

[0025] In one embodiment, several cell operating parameters are measured and transmitted by each measuring unit, the cell operating parameters including at least one of the following: cell voltage, cell temperature, cell current, cell internal resistance, and cell pressure. Thus, several parameters representative of the proper functioning of a battery cell can be measured for each battery cell.

[0026] According to one embodiment, each management unit communicates with the battery management unit via a dedicated data transmission bus or wireless links.

[0027] Thanks to the battery architecture which allows a large number of cells to be grouped into a small number of modules, it is possible to implement one or more buses or wireless links between the battery management unit and the module management units.

[0028] According to one embodiment, each management unit communicates with the battery management unit via electrical links connecting the module terminals together to form the branches and with the branch terminals and the negative battery terminal.

[0029] This arrangement avoids the need to add communication buses to the battery.

[0030] According to one embodiment, the management unit of each module and the battery management unit are configured to: emit by the battery management unit a request message in a modulated form by applying pulse bursts in the form of voltage drops between the positive and negative terminals of a branch to which the module is connected; receive the request message by each of the module management units belonging to the branch, by demodulating the pulse bursts between the terminals of the module to which the module management unit is connected;to emit by each module management unit of the branch, in response to the request message, a response message in a modulated form by applying pulse bursts in the form of voltage drops between the terminals of the module to which the module management unit is connected, during a respective time slot allocated to the module management unit, the response message containing data from a measurement of an operating parameter of the module; and to receive the response messages by the battery management unit, by demodulating the pulse bursts detected on the terminals of the branch.

[0031] The advantages of the transmission technique used between the measuring units of each module and the module management unit can thus also be obtained for transmissions between the module management units and the battery management unit.

[0032] According to one embodiment, each module management unit includes a power switch per branch to disconnect one of the branches when a cell in the branch is detected as faulty.

[0033] According to one embodiment, each measuring unit includes a wake-up circuit configured to detect a voltage drop across the cell terminals, and to activate a measuring unit processing unit upon detection of the voltage drop, the management unit being configured to generate the wake-up voltage drop.

[0034] According to one embodiment, each unit of measurement is realized in the form of a miniaturized integrated component embedded in one of the battery cells.

[0035] In one embodiment, each module management unit integrates a measuring unit as an integrated component to communicate with the module's measuring units, and / or the battery management unit. Each module management unit also integrates a measuring unit as an integrated component to enable the battery management unit to communicate with the battery management units and vice versa. In this way, communication between the module management units and the battery management unit is ensured exclusively between two measuring units. Thus, the communication protocol between the module management units and the battery management unit is implemented exclusively within a single measuring unit. Communication can therefore be encrypted without having to provide the secret data necessary for encryption, stored by the measuring units, to the manufacturer of the management units or the integrator assembling the batteries.Furthermore, these communications take place exclusively between a transmitting circuit and a receiving circuit within a unit of measurement, which are specifically matched to each other, particularly in terms of filtering. As a result, these communications are carried out optimally.

[0036] Brief description of the figs

[0037] The present invention will be better understood with the aid of the following description of exemplary embodiments with reference to the accompanying figures, in which identical reference symbols correspond to structurally and / or functionally identical or similar elements.

[0038] Figure 1 schematically represents a battery comprising a plurality of modules, each module comprising a plurality of cells, according to one embodiment,

[0039] Figure 2 schematically represents one of the battery modules, according to one embodiment,

[0040] Figure 3 schematically represents circuits of a measurement unit that can be associated with each of the battery cells, according to one embodiment,

[0041] Figure 4 schematically represents the circuits of a management unit that can be associated with each of the battery modules, according to one embodiment,

[0042] Figure 5 schematically represents the circuits of a battery management unit, according to one embodiment,

[0043] Figure 6 schematically represents a battery comprising a plurality of modules, according to another embodiment,

[0044] Figure 7 schematically represents the circuits of the battery management unit, according to another embodiment,

[0045] Figure 8 schematically represents one of the battery modules, according to another embodiment,

[0046] Figure 9 schematically represents circuits of a measurement unit that can be associated with each of the battery cells, according to another embodiment,

[0047] Figure 10 schematically represents a communication circuit of one of the measurement units, for communicating with a module management unit, according to one embodiment,

[0048] Figure 11 schematically represents the circuits of a management unit that can be associated with each of the battery modules, according to another embodiment,

[0049] Figure 12 schematically represents a communication circuit of one of the module management units, for communicating with a measurement unit, according to one embodiment. Figure 13 schematically represents circuits of a measurement unit that can be associated with each of the battery cells and that can be used in a module management unit, for communicating with a measurement unit, according to another embodiment.

[0050] Figure 14 schematically represents a communication circuit of one of the module management units, for communicating with a measurement unit, according to another embodiment,

[0051] Figure 15 schematically represents the steps of a communication process between a measurement unit associated with a battery cell and a module management unit, according to one embodiment,

[0052] Figure 16 schematically represents, as a function of time, data messages transmitted between the module management unit and the measurement units associated respectively with the battery cells, according to one embodiment,

[0053] Figure 17 schematically represents a battery comprising a plurality of modules, each module comprising a plurality of cells, according to another embodiment,

[0054] Figure 18 schematically represents the circuits of a management unit that can be associated with each of the battery modules, according to another embodiment.

[0055] Figure 19 schematically represents the circuits of a battery management unit, according to another embodiment,

[0056] Figure 20 schematically represents a communication circuit of the battery management unit, for communicating with other battery management units, according to another embodiment.

[0057] Figure 21 schematically represents a communication circuit of the battery management unit, according to another embodiment.

[0058] Detailed description

[0059] Figure 1 shows a low-voltage (LV) battery for electrical energy storage, according to one embodiment. The LV battery comprises several branches BR1, ..., BRb (where b is an integer greater than or equal to 2) connected in parallel. Each branch BRj (j = 1, ..., b) comprises several modules MD1, ..., MDm (where m is an integer greater than or equal to 2) connected in series, each module containing several cells. Each cell is configured to store electrical energy when electrically connected to a charging supply and to release this electrical energy when electrically connected to an electrical load.

[0060] In one embodiment, the BT battery comprises a BMU management unit including PTH and PTL terminals that can be connected to an electrical load or a charging circuit, positive terminals BTH1, ..., BTHb each connected to a respective positive terminal of one of the BRj branches, and a negative terminal BTL connected to a common negative terminal of each BRj branch. The BT battery also includes a DBS communication bus enabling the MDk modules (k = 1, ..., m) to exchange data with the BMU management unit.

[0061] Figure 2 shows an MD module that can be one of the MDk modules of one of the BRj branches, according to one embodiment. The MD module comprises several branches RM1, ..., RMr (where r is an integer greater than or equal to 2) connected in parallel. Each branch RMg (g = 1, ..., r) comprises several CL1, ..., CLn cells (where n is an integer greater than or equal to 2) connected in series. The CL1 cells can belong to an electrochemical category, such as supercapacitor or rechargeable battery. Generally, an electrochemical cell comprises two electrodes, a separator between the two electrodes, and an electrolyte.There are different types of cells in the rechargeable electric battery category, for example lithium-ion cells, Nickel Cobalt Aluminium-Graphite, Nickel Manganese Cobalt-Graphite, Nickel Cobalt Aluminium-Silicon, Nickel Manganese Cobalt-Silicon, Lithium Cobalt Oxide-Graphite, Lithium Iron Phosphate-Graphite, Lithium-Sulfur, Lithium Sulfide-Silicon, Sodium-ion, etc.

[0062] In one embodiment, the MD module (MDk) comprises a module management unit (MMU) including an MTH terminal connected to the MTL terminal of another module in the same branch BRj or to one of the BTHj terminals of the battery management unit (BMU), and an MTL terminal connected to the MTH terminal of another module in the same branch BRj or to the BTL terminal of the battery management unit (BMU). The module management unit (MMU) also includes positive terminals RTHg connected respectively to the positive terminals of the branches RMg and a negative terminal RTL connected to the negative terminals of the branches.

[0063] In one embodiment, each CLI cell is associated with a measurement unit MCi (i = 1, ..., n) connected to the two terminals of the cell and comprising communication circuits for communicating with the management unit MMU of the module in which it is located. Each measurement unit MCi is configured to acquire operating parameter values ​​for the cell and to transmit them to the management unit MMU. For this purpose, the MD module includes a communication bus DBM enabling the measurement units MCi to exchange data with the management unit MMU.

[0064] In one embodiment, the DBS and DBM buses can be wired, for example, of the CAN (Controller Area Network) type, commonly used in the automotive industry, or SPI (Serial Peripheral Interface). In another embodiment, the MD module's MMU and BMU include communication circuits for wireless communication, for example, using the Bluetooth or WiFi™ protocol. Communication links between the MCi measurement units and the MMU within the MD module and / or communication links between the MMU of the MDk modules and the BMU can also be implemented using optical fiber.According to another embodiment, the communication links between the MCi measuring units and the MMU management unit within each MDk module, and / or the communication links between the MMU management unit of the MDk modules and the BMU management unit are made by a star wired network.

[0065] Figure 3 illustrates the circuits of a measurement unit MC, which can be one of the MCi units associated with the battery cells CLi. Each MC unit comprises a processing unit UCC, a temperature sensor TS, a reference voltage generator VRG circuit, an ALM power supply circuit, a communication circuit COML that can be connected to the DBM bus, and optionally other sensors such as a pressure sensor PS and a current measurement circuit IM. The current measurement circuit IM can, for example, be interposed on a current line of the measurement unit MC between the negative terminal CTL and the positive terminal CTH of the associated CLi cell. The communication circuit COML is connected to the processing unit UCC to receive the data to be transmitted from the processing unit and to transmit the received data back to the processing unit.The UCC processing unit includes an analog-to-digital converter (CVN) with several inputs connected respectively to the temperature sensor (TS) and pressure sensor (PS), the reference voltage generator (VRG), the current measurement circuit (IM), and the positive terminal (CTH) of the cell (CLi) to which the measuring unit (MC) is connected for measuring the cell's voltage (Vc). The UCC processing unit is thus configured to receive measurements of temperature, pressure, voltage (Vc), and current (if applicable), to compare these measurements to threshold values, and to transmit these measurements or the results of these comparisons via the communication circuit (COML). The UCC processing unit may include a microcontroller comprising the CVN converter and volatile and non-volatile memory (MEM) for storing, among other things, software executed by the processing unit.The ALM power supply circuit generates a supply voltage SV from the cell voltage (between terminals CTH and CTL), which is then supplied to the UCC processing unit and the DC switching circuit. The VRG generator is configured to generate a highly stable voltage, independent of ambient temperature. Therefore, the reference voltage generated by the VRG can be used by the UCC processing unit as a reference voltage, particularly for precise operation of the CVN converter.

[0066] The MC unit can also be configured to enter a low-power sleep state during periods when it is not required to transmit status data from the associated CLi cell. For this purpose, the MC unit includes a DC switching circuit controlled by the UCC processing unit. The DC switching circuit includes switches connecting the voltage output of the ALM power supply circuit to the VRG generator and the TS temperature sensor, respectively. The DC switching circuit also includes an additional switch connecting the CTH positive terminal of the CLi cell to an input of the CVN converter. A wake-up signal can be transmitted via the DBM bus for detection by the COML circuit. Upon detecting the wake-up signal, the COML circuit activates the UCC processing unit by sending a signal to its designated input.The UCC processing unit can be configured to control the DC switching circuit when it becomes active, selectively powering on the TS temperature sensor and the VRG generator. Conversely, the UCC processing unit can be configured to enter an inactive state when the MC measuring unit is not being used by the MMU. In this case, the UCC processing unit is configured to control the DC switching circuit before entering an inactive state, thus de-energizing the various TS, PS, etc. sensors and the VRG generator. With these arrangements, the various sensors and the VRG generator can be powered, and the cell voltage (Vc) can be supplied to the CVN converter only when required.

[0067] In cases where the COML communication circuit communicates wirelessly with the MD module's MMU management unit, it may be desirable to be able to power off the COML circuit. For this purpose, the CC circuit can include an additional switch interposed between the ALM power supply circuit and the COML circuit. A wake-up circuit such as the WU circuit (described below with reference to Figure 10) can be provided to wake up the MC unit, with the WU circuit configured to detect wake-up signals emitted by the electrical connections between the MC module and the CLi cells.

[0068] The MC unit can also include a voltage monitoring circuit (VM) configured to monitor the voltage across the CTH and CTL terminals of the associated CLi cell, in redundancy with the UCC processing unit. For this purpose, the VM is connected to the CTH and CTL terminals of the associated CLi cell and is configured to compare the voltage across the CTH and CTL terminals of the CLi cell to maximum and minimum voltage safety threshold values. These maximum and minimum voltage safety thresholds are related to the electrochemical couple of the CLi cells. Indeed, depending on this electrochemical couple, the voltages reached at the end of charging and / or discharging are not the same. These voltage safety thresholds can be pre-programmed in the MC measuring units, independently of the software run by the UCC processing unit, which prevents them from being exceeded during normal operation.In the event of a hardware or software malfunction of the MC measurement unit, the VM circuit is configured to block transmissions from the COML circuit to the MMU if these thresholds are exceeded. Thus, the VM circuit helps prevent incidents, particularly those caused by a failure of the UCC processing unit.

[0069] The voltage thresholds applied by the VM circuit can be configured according to the desired operating range of the associated CLi cell and stored in the MMU's memory. These thresholds are then transmitted to the MD module's MCi measurement units and processed by their respective UCCs. The high voltage at the end of charging can be lowered, and / or the minimum voltage at the end of discharge can be increased. Similarly, maximum and minimum temperature thresholds can be stored in the MMU's memory, adapted to the battery architecture, and transmitted to and stored in each UCC's memory for processing. By avoiding exceeding these voltage thresholds, the structure of the active materials in the CLi cell degrades less rapidly, thus increasing the lifespan of the CLi cell and, consequently, the battery.

[0070] In one embodiment, the MC unit (MCi) is implemented as a miniaturized integrated component, for example, as an ASIC (Application-Specific Integrated Circuit) or a SoC (System on Chip). The MC unit can also be configured to connect easily to the CTH and CTL terminals of a CLi cell. This allows the MC unit to be readily integrated into each battery cell without increasing its overall size. Sensors, particularly those for temperature, voltage, and pressure, can therefore be positioned as close as possible to the cell's electrochemical core, thus providing more accurate measurements. The IM current sensor can also be, for example, a Hall effect sensor connected to a link between the CTL and CTH terminals.

[0071] Figure 4 shows the circuitry of one of the MMUs for managing and monitoring a BT battery MDk module. The MMU includes a UCM processing unit, an ALM1 power supply circuit, and CMMC and CMMB communication circuits. Figure 4 also shows the negative RTL terminal of the MMU connected to the negative terminals of the RMg branches (g = 1, ..., r) of the MDk module, and the positive RTHg terminals of the MMU connected to the positive terminals of the branches, respectively. The MMU also includes a positive MTH terminal and a negative MTL terminal, which serve as module connection terminals. The positive MTH terminal is intended to be connected to the negative terminal of another module or to one of the BTHj terminals of the BMU, and the negative MTL terminal is intended to be connected to the positive terminal of another module or to the BTL terminal of the BMU.The MMU can also implement a wake-up function for the MCi units present in the corresponding MDk module and connected to the MMU. Each of the RTHg terminals is connected to an EM junction point at the module's Vmd voltage via a power switch SW1, SWr. Each SWg switch (g = 1, r) allows disconnection of the corresponding RMg branch, particularly when one of the CLi cells in the branch is detected as faulty or when communication with an MCi measurement unit in the branch is lost. The SWg switches are implemented, for example, using MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). Furthermore, the EM junction point is connected to the MTH terminal.

[0072] The ALM1 power supply circuit generates from the module's internal voltage Vmd, a supply voltage SV1 which is provided to the UCM processing unit and the CMMC, CMMB communication circuits.

[0073] The UCM processing unit includes an analog-to-digital converter CVN1 with several inputs receiving voltages Vh1 and Vh2 taken from terminals RTHg, respectively, and the internal voltage Vmd. The UCM processing unit is also configured to control the SWg switches, each of which is closed until a faulty CLi cell belonging to the corresponding RMg branch is detected. The SWg switches can also be opened during periods of battery storage or transport, notably to increase safety. The CMMC and CMMB communication circuits are connected to the UCM processing unit to receive data to be transmitted from the UCM processing unit and to transmit received data to the UCM processing unit.

[0074] Figure 5 shows the circuits of the BT battery management and monitoring unit (BMU) according to one embodiment. The BMU comprises a processing unit (UCB), a power supply circuit (ALM2), and a communication circuit (COMB). Figure 5 also shows the negative terminal (BTL) of the BMU connected to the negative terminals of the BRj branches, and the positive terminals (BTHj) (j = 11, ..., b) of the BMU connected to the positive terminals of the BRj branches. The BMU may also include two positive terminals (PTH1 and PTH2) and one negative terminal (PTL) forming external terminals for the BT battery. The positive terminals (PTH1 and PTH2) are intended to be connected to an LD load and a CHC charging circuit, respectively, which are also connected to the negative terminal (PTL). However, the same positive terminal may be used for both charging and discharging the BT battery.The BMU unit has as many positive terminals BTHj as the BT battery has branches BRj. The BMU unit may also include a function for waking up the MMU units present in the BT battery and connected to the BMU unit.

[0075] Each of the BTHj terminals is connected to a junction point EP at the battery voltage Vbt. The junction point EP is connected to each of the PTH1 and PTH2 terminals via a low-pass filter L2, C2 in series with a respective power switch SW3 and SW4. The low-pass filter L2, C2 comprises a capacitor C2 connected between the junction point EP and ground, and an inductor L2 connected between the junction point EP and the two power switches SW3 and SW4. The combination of capacitor C2 and inductor L2 forms a low-pass filter. The switches SW3 and SW4 are controlled by the processing unit UCB, with only one switch being closed depending on whether the charging or discharging operation is in progress.

[0076] The ALM2 power supply circuit generates a supply voltage SV2 from the internal voltage Vbt, which is then supplied to the UCB processing unit and the COMB communication circuit. The UCB processing unit includes an analog-to-digital converter CVN2 with several inputs receiving voltages Vh11 and Vh1b, respectively taken from terminals BTH1 and BTHb, and the internal voltage Vbt. The CVN2 converter may also include inputs connected to the terminals of a current sensor, for example, a resistive component interposed across the connection between terminals BTL and PTL, to measure the current flowing between the terminals of the BT battery. The current sensor may also be a Hall effect sensor placed across a connection between terminals BTL and PTL.

[0077] Figure 6 represents a BT1 battery comprising a plurality of branches BR1, ..., BRb, each branch comprising a plurality of MDk modules, each module comprising a plurality of cells, according to another embodiment. The BT1 battery differs from the BT battery in that it includes a DB1, DB2, ..., DBb data transmission bus for each branch BR1, BR2, BRb. Thus, the MMU management units of the MDk modules in each branch BRj communicate with the battery's BMU management unit via their respective DBj bus.

[0078] Figure 7 shows the circuits of a BMU1 battery management and monitoring unit for BT1, according to one embodiment. The BMU1 differs from the BMU in that it comprises as many CMB1, ..., CMBb communication circuits as there are BRj branches in the BT1 battery, each CMBj communication circuit being connected respectively to one of the DBj buses and to the UCB processing unit. Each CMBj circuit receives the SV2 supply voltage and is connected to the BTL terminal.

[0079] Figure 8 shows one of the MD' modules of the battery, according to an alternative embodiment. The MD' modules differ from the MD modules in that the MD module's MMU management unit is replaced by an MMU1 management unit, and the MC'i measurement units of the CLi cells communicate with the module's MMU1 management unit via the electrical connections between the CLi cells of the module's RMg branches and the RTHg and RTL terminals of the MMU1 unit. Thus, the MD' modules do not have a DBM bus.

[0080] Figure 9 shows circuits of a measurement unit MC' which can be one of the measurement units MC'i associated respectively with the CLi cells of the battery, according to another embodiment. The measurement unit MC' differs from the measurement unit MC in that it includes a communication circuit CML1. The communication circuit CML1 differs from the COML circuit in that it is configured to use the links between the CLi cells of the module MD' and the management unit MMU1 of the module MD' in which it is located, to communicate with the management unit MMU1. This embodiment has the advantage of limiting the number of wires that need to be run out of the sealed enclosure containing the CLi cell. Indeed, the cell's lifespan can be drastically reduced if this seal is absent or lost.

[0081] Like the MC unit of measurement, the MC' unit of measurement can also include the VM circuit for monitoring the voltage across the terminals of the CTH, CTL of the associated CLI cell.

[0082] The MC' unit may also include a wake-up circuit WU configured to awaken the MC' measuring unit from a low-power sleep state during periods when it is not being used to transmit status data from the associated CLI cell. To this end, the wake-up circuit WU is configured to detect a wake-up signal on the CTH terminal and activate the UCC processing unit by sending a signal to a designated input when it detects the wake-up signal. The UCC processing unit can be configured to control the CC switching circuit when it becomes active, in order to selectively power on the TS temperature sensor, the VRG generator, and the CML1 communication circuit. The UCC processing unit can be configured to enter an inactive state when the MC' measuring unit is not being used by the MMU.The UCC processing unit is then configured to control the CC switching circuit before switching to the inactive state, in order to turn off the various sensors (TS, PS, ...), the VRG generator and the CML1 communication circuit.

[0083] Figure 10 shows the CML1 communication circuit for the MC' measurement units. The CML1 circuit comprises a TXT transmit stage and an RXT receive stage. The TXT transmit stage includes a signal mixing SMC circuit that receives a TXS data signal to be transmitted from the UCC processing unit at the Tx input of the CML1 circuit, a low-pass filter F1 connected to the output of the SMC circuit, and a slope control SLC circuit connected to the output of filter F1. The output of the SLC circuit is connected to a control terminal of a switch T1. Switch T1 connects the CTL terminal of the associated cell to a dissipative component R1, which is otherwise connected to the CTH terminal of the associated cell.The SMC circuit is configured to modulate a carrier wave with the TXS signal. This carrier wave can be a clock signal CK (or a clock signal at a frequency defined by such a clock signal) provided, for example, by the UCC processing unit, or a clock circuit within the MC' measurement unit. The frequency of the CK clock signal can be, for example, more than ten times the data rate of the TXS data signal. The signal produced by the SMC circuit can thus consist of bursts of square waves, each burst corresponding, for example, to a 1 in the TXS data signal, with the signal between bursts corresponding to one or more 0s. The SLC circuit is configured to transform the signal provided by the filter F1 into a signal consisting of bursts of pulses with a substantially sinusoidal shape. Thus, the switch T1 is controlled to produce bursts of pulses in the form of voltage drops across the CTH and CTL terminals of the associated CLi cell.The essentially sinusoidal shape of the pulses allows for signals with a Fourier spectrum consisting of essentially a single line. For example, the TXS data signal can have a frequency of a few tens of kHz, while the CK clock signal can have a frequency of a few MHz. TXS and RXS data signals are, for example, configured as frames conforming to the UART (Universal Asynchronous Receiver Transmitter) protocol.

[0084] Switch T1 can be a bipolar transistor, for example, of the npn (or pnp) type, with its base connected to the output of the SLC circuit, its emitter connected to the negative terminal CTL, and its collector connected to the dissipative component R1. Transistor T1 can also be an N-type or P-type MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), with its gate connected to the output of the SLC circuit, and its conduction terminals connected to component R1 and the CTL terminal, respectively. The dissipative component R1 can be a resistor.

[0085] The TXT transmission stage may also include a SW switch controlled directly by the VM circuit to block transmissions from the CML1 circuit to the MMU1 unit when the UCC unit is faulty.

[0086] The RXT receiver stage comprises a capacitor CX connected to the CTH terminal of the associated cell, a resistor R10 connected to capacitor CX, a bandpass filter F2 connected to resistor R10, a voltage amplifier VA connected to the output of filter F2, an envelope detection EVD circuit connected to the output of the VA amplifier, and a comparator CP1 connected to the output of the EVD circuit and receiving a reference voltage Vrf. The reference voltage Vrf is, for example, generated from the voltage at the CTL terminal in unit MC'. The EVD circuit generates an envelope signal from pulse bursts present in the data signal received through capacitor CX. Capacitor CX eliminates the DC component and thus extracts the transmission signal from the voltage at the CTH and CTL terminals of the cell.Comparator CP1 compares the envelope signal provided by the EVD circuit to the reference voltage Vrf to generate a square wave signal, either 0 or 1 depending on whether the envelope signal is lower or higher than the reference voltage. Comparator CP1 provides an RXS signal of received data to the UCC processing unit. Filter F2 removes Fourier spectrum lines from the received signal and eliminates unwanted frequencies from the environment or load, retaining only the frequency band of the useful communication signal.

[0087] Figure 11 schematically represents the circuits of the MMU1 management unit, which can be associated with each of the battery modules, according to another embodiment. The MMU1 management unit is configured to communicate with the MC' measurement units of the MD' module using the electrical connections between the CLi cells of the module and between the MMU1 unit and the RMg branches of the module. To this end, the MMU1 unit differs from the MMU unit in that the CMMC communication circuit is replaced by a CMM1 communication circuit, which is connected to the EM junction point of the MMU1 module and to its RTL terminal. The CMM1 circuit is configured to transmit and receive messages via the electrical connections between the cells of the MD' module and the RTHg and RTL connection terminals of the RMg branches of the MD' module. Furthermore, the power switches SW1, ..., SWr are each connected in parallel with their respective capacitors C11, ..., C1r.The C1g capacitors maintain communication with the MCi measurement units of the corresponding RMg branch when the corresponding SWg switch is open. The capacitance of the C1g capacitors is adjusted so as not to disrupt (attenuate, distort) the transmissions.

[0088] The MMU1 unit may also include a wake-up circuit WU1 that wakes up the MC' units present in the corresponding MD' module and connected to the MMU1 unit. The wake-up circuit WU1 can be implemented, for example, using a resistive or dissipative component coupled to a power switch controlled by the UCM processing unit and connected to the EM junction point. The UCM processing unit is configured to briefly close the power switch in the WU1 circuit to generate a short voltage drop at the EM junction point. This voltage drop is transmitted to the CLi cells connected to the MTHg terminals and is detected by the wake-up circuit WU of each of the MCi measuring units associated with these cells, thus "waking up" the MCi measuring units and synchronizing them.

[0089] Figure 12 schematically represents the CMM1 communication circuit of one of the MMU1 module management units, used to communicate with the MC'i measurement units, according to one embodiment. In this embodiment, communication between the MMU1 management unit and the MC'i measurement units is achieved by modulating the voltage present between the RTHg terminal and the RTL terminal. The CMM1 circuit comprises a TXT1 transmit stage and an RXT1 receive stage. The RXT1 receive stage can be identical to the RXT stage of the CML1 circuit. The TXT1 transmit stage differs from the TXT stage of the CML1 circuit in that it includes an AP amplifier, and the switch T1 and the dissipative component R1 are replaced by a switch M1 and a dissipative component R2 connected in series between the EM junction point and the RTL terminal of the MMU1 management unit of the MD' module.Switch M1 is sized to be able to switch the high voltages present across the terminals of the RMg branches of module MD'. Amplifier AP amplifies the control voltage supplied by the SLC circuit, in order to obtain a voltage sufficient to control switch M1.

[0090] The switch M1 can be an N-type or P-type MOS transistor, whose gate is connected to the output of the amplifier AP, and whose conduction terminals are respectively connected to the negative terminal CTL and the dissipative component R2. The dissipative component R2 can be a resistor.

[0091] It turns out that the voltage drops generated by the control of switch T 1 are only visible at the terminals of the RMg branch to which the associated cell CLi belongs, but not by the other MC'i units of the same branch.

[0092] In contrast, the voltage drops generated by the control of transistor M1 in the CMM1 circuit are visible simultaneously to all MCi units of the MD' module. Furthermore, this modulation of the voltage across a cell or branch by voltage drops is, by its very nature, not subject to attenuation.

[0093] The voltage drops generated by the MC' measuring units have an amplitude of a few tens of millivolts, for example, 30 mV ±10%. Furthermore, the voltage drops generated by the MMU1 management units are applied to the terminals of the RMG branches of the MD' module. They are therefore distributed across the terminals of each cell in the MD' module. Thus, the voltage drops generated by the MMU1 management units have a specific amplitude to be visible to all the MC' measuring units in the module. To this end, the voltage drops generated by each MMU1 management unit can have an amplitude equal to at least the amplitude of the voltage drop applied by each of the measuring units, multiplied by the number of CLi cells connected in series in each RMg branch, and taking into account the number of branches in parallel in the MD' module.

[0094] It should be noted that the voltage across an RMg branch by each MMU unit is much greater than the voltage across a CLi cell by MCi units. The CMM1 circuit therefore differs from the CML1 circuit in that it is adapted to the voltage present between the EM junction point and the RTL terminal.

[0095] This transmission method, which uses voltage drops on the cell power line, differs from power line communication (PLC) transmission, which involves injecting an amplitude-modulated carrier signal onto the power line, with the cell terminals interconnected by a capacitor. The modulated carrier signal injected in this way, as a current modulation, undergoes significant attenuation that increases as it propagates. Consequently, a signal transmitted via power line communication must be repeated at each cell to reach its intended recipient. Therefore, a transmitted message is necessarily processed by multiple cell circuits.Such repeated transmissions also result in significant transmission delays, an increased risk of errors, and high energy consumption, which, in the context of a battery, impacts battery life. Due to these significant transmission delays, power line communication (PLC) transmission technology cannot monitor a very large number of individual cells with sufficiently short response times to trigger effective battery protection measures following the detection of a cell failure.

[0096] Furthermore, an isolation circuit (ISC) can be interposed in the MMU1 circuit on the connection between the EM junction point and the MTH terminal to prevent voltage drops generated by the CMM1 circuit from being disturbed by spurious signals originating outside the module. The isolation circuit (ISC) can be a simple inductor. It should be noted that the voltage drops generated by the CMM1 circuit can be transmitted outside the MD' module, but these are only seen at the terminals of the BRj branch to which the module is connected. To prevent these voltage drops from being detected by modules on other branches, the battery management unit (BMU1) can include an inductor connected upstream of each BTHj terminal.

[0097] In one embodiment, each MCi measuring unit implements a cell balancing function, CLI. This function aims to optimize the recovery of the highest possible battery capacity. Indeed, each cell evolves differently and has different charge and discharge rates, depending on its individual capacity. During battery charging, as soon as a cell reaches a maximum voltage, known as "Over Voltage," charging must be interrupted to prevent overheating or even battery destruction. This means that the entire battery is dependent on the cell that reaches the end of its charge the fastest. In this case, the other cells in the battery are not fully charged. Therefore, it is not possible to utilize the battery's total capacity.

[0098] The balancing function involves measuring cell voltages during, for example, a battery charging operation, and based on these measurements, slowing down the charging of the fastest-charging cells (those whose voltage changes most rapidly) by switching on a balancing resistor connected in parallel with the cell. In this way, a portion of the charging current is diverted away from the cell and therefore does not contribute to its recharging. This diverted portion of the charging current is adjusted so that, at the end of the charge, all cells have the most homogeneous measured voltages possible. For example, the balancing function might aim for a final cell voltage difference of less than 1%. This function can be implemented by the CML1 communication circuit.Indeed, thanks to the dissipative component R1 coupled to transistor T1, which is controlled by the processing unit UCC, each MCi measuring unit can balance its associated CLi cell. Furthermore, the cell balancing function can be performed based on increasingly precise measurements the closer the MCi measuring unit can be placed to the associated CLi cell.

[0099] The balancing function can consist of either controlling the closure of transistor T1 for a fixed duration, for example, 100 ms, or diverting a variable amount of current by acting on the gate control of transistor T1, when the voltage Vc of the CLi cell measured by the UCC unit is greater than a minimum setpoint voltage Vmin plus a delta value, which depends on the difference between the minimum and maximum setpoint voltages. The minimum and maximum setpoint voltages can be provided by the MMU1 management unit. Thus, the UCC processing unit can be configured to perform the balancing function during a battery charging operation.The balancing function can also be performed for long-term battery storage to limit the amount of energy stored in the cells, knowing that in long-term storage, the more the battery is charged, the more dangerous it is and the more it ages prematurely.

[0100] In the case of MCi measuring units, with the COML communication circuit, it should be noted that the transistor T1 in series with the dissipative component R1 (present in the CML1 circuit) can be provided in the MCi measuring units only to perform this balancing function, the transistor T1 then being controlled by the UCC control unit.

[0101] Figure 13 shows circuits of a measurement unit MC" which can be one of the measurement units associated with the CLi cells of the battery, according to another embodiment. The measurement unit MC" differs from the measurement unit MC' in that it includes a communication circuit CML2 replacing the communication circuit CML1. The CML2 circuit is configured so that the measurement unit MC" can be used as a communication circuit for one of the module management units MMU1, to communicate with the measurement units MC' or MC" associated with the CLi cells of the module. To this end, the CML2 circuit differs from the CML1 circuit in that the output of the SLC circuit is connected to an additional TO output terminal of the MC" unit. The TO output is intended to be connected to the AP amplifier circuit controlling the switch M1. In this way, part of the MMU1 circuit can be implemented using the MC" circuit.

[0102] Figure 14 schematically represents a CMMT communication circuit replacing the CMM1 communication circuit in the MMU1 module management units, according to one embodiment. In this embodiment, the CMMT communication circuit is implemented using the MC circuit. The TO output of the MC circuit is connected to the AP amplifier circuit controlling switch M1, and the CTH output of the MC circuit is connected to the EM junction point of the MMU1 circuit via a capacitor C3 to isolate the CTH terminal from the module voltage present at the EM junction point. The conduction terminals of switch M1 are connected to resistor R2 and terminal RTL of the MMU1 management unit, respectively. Resistor R2 is connected to the EM junction point of the MMU1 circuit.Furthermore, the supply voltage SV1 provided by the power supply circuit ALM1 is applied to the CTH terminal of the MC circuit via an inductor L3 to prevent the communication signals supplied to the CTH terminal from being attenuated or the module management unit MMU1 from being polluted by spurious signals. The MC unit exchanges transmit data (TXS') and receive data (RXS') with the processing unit UCM. The TXS' signals are converted to TXS signals by the MC unit's processing unit UCC, and the RXS signals are converted back to RXS' signals by the processing unit UCC. Signal transformation processes can include, for example, encryption / decryption processes to ensure that the data transmitted between the MMU1 of the MD module and the MC' or MC circuits associated with the module's CLi cells are encrypted.

[0103] In this way, communication between the MC' or MC" measuring units associated with the module's CLi cells and the module's MMU1 management unit is ensured exclusively between two MC" measuring units. Thus, the communication protocol between the measuring units and the module's management unit is implemented solely within an MC" unit. Communications can therefore be encrypted without having to provide the secret data necessary for encryption, stored by the MC" units, to the manufacturer of the MMU1 units or the integrator assembling the batteries. Furthermore, this communication takes place exclusively between a TXT transmit circuit and an RXT receive circuit of the CML2 circuit of an MC" unit, which are specifically matched, particularly in terms of filtering. As a result, this communication is carried out optimally.

[0104] Figure 15 illustrates steps S1 to S10 of a data exchange process between the UCM processing unit of one of the MMU1 units of one of the MD'k modules and the UCC processing unit of one of the MC' measurement units belonging to the MD'k module. In step S1, the MMU1 unit selects a type of FR message to transmit, for example, based on the current battery state (charging, discharging) or based on any previous exchanges with the MC' units. This could be, for example, a configuration message containing battery operating and configuration parameters, or a message requesting measurement and / or status data following the detection of a fault on a cell.

[0105] In step S2, unit MMU1 transmits a message FR1 of the selected type. In step S3, the message FR1 is received by all connected units MC', approximately simultaneously. Each unit MC' receives the message FR1 and determines its type. If the type of the received message FR1 requires a response from the unit MC', it triggers a timeout TMP in step S4. This timeout can depend on the type of the received message FR1 and a time slot J allocated to it. After the TMP timeout, unit MC' selects a message type to send in response to message FR1, generates a message CFR_J (J = 1, ..., N, where N is the number of CLI cells in module MD') corresponding to the selected type and containing the required data. In step S6, unit MC' sends the CFR_J message in response during its allocated time slot J. At step S7, the MMU1 unit receives the CFR_J message, and determines the type of the CFR_J message.The S7 stage ends when the MMU1 unit has received messages from all the MC' units of the MD' module or when all the time slots allocated to the MC' units to send a reply message have elapsed.

[0106] The following steps, S8 to S10, may be optional and depend on the type of CFR_J messages. In step S8, the MMU1 unit selects a message type to send in response to the CFR_J message. In step S9, the MMU1 unit generates an FR2 message corresponding to the selected type and containing the required data. In step S10, the MC' unit receives the FR2 message and executes step S3 again, and optionally steps S4 to S6 if a response is required.

[0107] Figure 16 illustrates a message exchange between the MMU1 unit and the MC' units of the MD' module, according to one embodiment. This message exchange is initiated by the MMU1 unit sending a message FR1 of a given type (step S2). The FR1 message is received approximately simultaneously by all N MC' units connected to the MMU1 unit. The MC' units then send a response (step S6) with a CFR_J message of a type corresponding to the type of the FR1 message. For this purpose, each MC' unit uses a time slot that has been previously allocated to it. Upon receiving the CFR_N message corresponding to the last allocated time slot N, the MMU1 unit sends a message FR2, which can be an end-of-exchange message or a message requesting status data from the CLi cells of the MD' module.

[0108] In one embodiment, a time slot is assigned to each MC' unit connected to the MMU1 unit by an initialization message FR1. For example, the processing unit (UCC) of each MC' unit stores a unique identifier known to the MMU1 unit. The initialization message contains a list of all the identifiers of the MC' units connected to the MMU1 unit, each associated with a time slot number. The identifiers of the MC' units connected to the MMU1 unit can be provided to the latter during a configuration phase when assembling the cells to form the battery.

[0109] In another example, each MC' unit randomly determines, or determines based on its unique identifier, a time slot number and responds to the initialization message FR1 with a CFR_J reply message containing, for example, its unique identifier during the corresponding time slot. In response, the MMU1 unit sends an allocation message containing the received MC' unit identifiers associated with a time slot number. If two MC' units have thus allocated themselves the same time slot, a collision occurs. In this case, the CFR_J messages sent by these two MC' units are not correctly received by the MMU1 unit, which detects, for example, a CRC error. If the MMU1 unit has not received a CFR_J message from each of the MC' units (considering the number of cells in the MD' module), the MMU1 unit retransmits the initialization message.Only the MC' units of the MD' module that have not received a time slot number associated with their identifier respond during a new time slot determined randomly or from their identifiers.

[0110] This procedure can be performed branch by branch for all RMg branches of the MD' module, by controlling the SWg switches, so that only one branch is connected, so that only the units of the connected branch receive and respond to the initialization message.

[0111] Each time an MC' unit has to transmit a CFR_J message (step S6), the TMP timing applied in step S4 corresponds to the duration of a time slot times J-1, from the moment of receipt of the FR1 message in step S3.

[0112] In one embodiment, the MMU1 unit periodically sends a cell status request message (FR1) (step S2), and the MC' units respond with a CFR message containing the cell status (OK or KO), and optionally the unique identifier of the MC' unit or part of that identifier. Thus, the exchanged messages are reduced to the bare minimum size to obtain a status for each cell in the module, while also limiting the power consumption associated with these exchanges. Upon receiving the CFR_J messages sent by the MCi units in step S6, the MMU1 unit determines whether all the MC' units connected to the MMU1 unit have responded and whether the responses indicate a cell failure. If no failure is detected and all the MC' units have responded, the FR2 message sent by the MMU1 unit in step S9 terminates the communication. The MC' units can then enter an inactive state to minimize their power consumption.Otherwise, the FR2 message contains a request for measurement data to allow the MMU1 unit to determine the cause of the failure. The MC' units then respond (step S3) with a CFR message containing a voltage measurement and / or a temperature measurement, and / or possibly a pressure measurement. Upon receiving all the measurement data transmitted by the MCi' units in step S7, the MMU1 unit can analyze this data (calculating averages, minimum / maximum voltage and temperature values, etc.) and send back an FR2 frame containing the calculated minimum and maximum values ​​in step S9. Depending on the detected failure, the MMU1 unit can then decide whether to disconnect the RMg branch to which the faulty cell belongs using the corresponding SWg switch.

[0113] In one example, each message FR1, FR2, CFR_J contains a header block, a termination block, and optionally a data block. The termination block may include a Cyclic Redundancy Check (CRC) code or a checksum to determine if the message was transmitted correctly. The message may also include error correction codes.

[0114] Based on the data transmitted by the MC' measuring units, the UCM processing unit of the MMU1 unit can perform various control operations. For example, the UCM processing unit can calculate the internal resistance of each CLi cell from voltage measurements across the cell's CTH and CTL terminals and the current measured in each RMg branch of the MD' module, for instance, during charging when the charging current is perfectly stabilized and controlled. The internal resistance of each CLi cell can be determined by dividing the difference in voltages measured across the cell, with and without current in the branch to which the CLi cell belongs, by a measurement of that current. These two voltage measurements across the cell can be transmitted from the MC' measuring unit to the MMU1 unit.

[0115] According to another embodiment, the MMU1 unit can transmit to each MCi measuring unit of the corresponding module the value of the current measured in the branch where it is located, and each MCi unit of the module can calculate and store the internal resistance of the CLi cell to which it is associated using the received branch current value and the voltage values ​​measured at the CTH, CTL terminals of the associated CLi cell, in the presence and absence of current in the branch to which the CLi cell belongs.

[0116] Knowledge of the internal resistance of each CLi cell and its evolution over time provides fundamental information regarding its state of health (SOH). Indeed, an abnormal drift in a cell's internal resistance indicates premature aging or a manufacturing defect.

[0117] Knowing the internal resistance of each Li-ion cell, combined with cell temperature measurements, can also optimize charging, either by adjusting the voltage and / or current delivered by the charger, or by limiting the charging time. This limits cell heating and maximizes energy recovery within an optimal timeframe. Using a "smart" charger that communicates with the BMU (Battery Management Unit) can enable this optimization.

[0118] Furthermore, the battery topology—that is, knowledge of the battery assembly configuration: the number of cells in series in each branch and the number of branches in parallel in each module—is a determining parameter and impacts the communication mode, particularly the data transmission rate between the MC' measuring units and the MMU1 management unit of the MD' module to which the measuring units belong. In one embodiment, this information is configurable and stored in the MMU1 management unit's memory for use by the UCM processing unit. Additionally, the frequency of the FR1 messages emitted by the MMU1 unit can be adjusted according to the battery's usage patterns.Thus, in a "power" operating mode where higher charge and / or discharge rates of the BT1 battery are required, it may be necessary to transmit the maximum and minimum voltage commands from the MMU1 unit and the measurements taken by the MC' units more frequently. Conversely, in an "energy" operating mode, where charge and / or discharge rates are slow, the transmission frequency of the FR1 messages does not need to be high. Figure 17 shows a BT2 battery with a plurality of modules, each module containing a plurality of cells, according to another embodiment. The BT2 battery differs from the BT or BT1 battery in that it includes a BMU2 management unit, does not include a DBS or DBj bus, and the MDk modules are replaced by MD"k modules.The BMU2 management unit differs from the BMU or BMU1 unit in that it includes for each branch a communication circuit with the module management units, this communication circuit using the electrical links between the MD"k modules of the battery.

[0119] Figure 18 shows circuits of a management unit MMU2 for each of the MD"k modules of the BT2 battery, according to another embodiment. The management unit MMU2 differs from the MMU1 unit (Figure 11) in that the CMMB communication circuit is replaced by a CMM2 communication circuit connected between the MTH and MTL terminals of the MD"k module. The CMM2 communication circuit may have the same architecture as the CMM1 circuit (Figure 12). The switch M1 and the amplifier AP of the CMM2 communication circuit are sized to be able to switch the voltages present between the MTH and MTL terminals. Furthermore, the MMU2 unit may include an isolation circuit ISC1 interposed on the connection between the EM junction point and the MTH terminal to prevent voltage drops generated by the CMM1 circuit from being transmitted outside the module, i.e., to the other MD"k modules of the same BRj branch.The ISC1 isolation circuit is also configured to prevent voltage drops generated by the CMM2 circuit from being transmitted to the branches. The ISC1 isolation circuit can be a simple inductor or an LC circuit.

[0120] In another embodiment, the ISC1 circuit is omitted, and the CMM1 and CMM2 communication circuits modulate the voltage in different frequency bands sufficiently separated so as not to interfere with each other. Alternatively, separate time slots can be allocated to the cells and modules.

[0121] It can be observed that the CMM1 and CMM2 communication circuits can be replaced by the CMMT circuit (figure 14).

[0122] Figure 19 shows the circuits of a battery management unit BMU2, according to another embodiment. The BMU2 management unit differs from the BMU1 unit (Figure 7) in that the CMBj communication circuits are replaced by CB1j communication circuits configured to communicate with the CMM2 communication circuits of the MD"k modules present in the BT2 battery. Each CB1j communication circuit is connected to the EP junction point, to one of the respective BTHj terminals, and to the BTL terminal of the BMU2 unit. Each CB1j communication circuit communicates with the UCB processing unit to transmit data received from a respective BRj branch and to receive data to be transmitted to the BRj branch.

[0123] Figure 20 shows a CB1 communication circuit for communicating with the MMU2 management units of the MD"k battery modules, according to one embodiment. The CB1 communication circuit can be any of the CB1j communication circuits of the BMU2 battery management unit. The CB1 communication circuit differs from the CMC1 circuit in that it includes an inductor L4 connected between the EP junction point and the BTH terminal (BTHj). The inductor L4 prevents voltage-modulated signals from one of the modules from being visible to the MD"k modules of the other BRj branches of the battery. The switch M1 and the AP amplifier of the CB1 communication circuit are sized to be able to switch the voltages present between the BTH and BTL terminals. Thus, to be able to switch voltages of several hundred volts, the switch M1 can be an IGBT (Insulated-Gate Bipolar Transistor).

[0124] Communications between the module MMU2 management units and the battery BMU management unit can take place as described previously with reference to Figures 15 and 16.

[0125] Furthermore, the module management units (MMU, MMU1, MMU2) can transmit, upon request from the battery management unit (BMU, BMU1, BMU2), the status of the module's CLi cells or the presence of faulty cells within the module. This includes the minimum and maximum voltage thresholds applied by the module's MC' measuring units, the minimum and maximum temperature readings provided by the module's cells, and the minimum and maximum internal resistance values ​​provided by the module's cells. The battery management unit can also transmit commands or authorizations to the module management units to open or close the SWg switches at the branch head, depending on whether the battery is in charge or discharge mode, balancing, long-term storage, wake-up mode, etc.

[0126] Figure 21 shows one of the CBT communication circuits of the BMU2 unit, according to another embodiment. The CBT circuit replaces each of the CB1j communication circuits of the BMU2 unit (Figure 19). In this embodiment, the CBT communication circuit is implemented using the MC circuit (Figure 13). The TO output of the MC circuit is connected to the AP amplifier circuit, which controls switch M1, and the CTH output of the MC circuit is connected to the BTH (BTHj) terminal of the BMU2 unit via capacitor C5 to isolate the CTH terminal from the battery voltage. Thus, capacitor C5 blocks the DC component present at the BTH terminal from the CTH input. The conduction terminals of switch M1 are connected to resistor R2 and the BTL terminal of the BMU2 control unit, respectively. Resistor R2 is connected to the BTH (BTHj) terminal of the BMU2 unit.The CBT circuit also includes an inductor L4 connected between the EP junction point and the BTH terminal (BTHj). Furthermore, the supply voltage SV2 provided by the ALM2 power supply circuit is applied to the CTH terminal of the MC circuit via an inductor L5 to prevent the communication signals supplied to the CTH terminal from being attenuated or the BMU2 management unit from being polluted by spurious signals. The MC unit exchanges transmit data (TXS') and receive data (RXS') with the UCB processing unit. The TXS' signals are converted to TXS signals by the UCC processing unit of the MC unit, and the RXS signals are converted to RXS' signals by the UCC processing unit.Signal transformation processes can, for example, be encryption / decryption processes so that the data transmitted between the BMU2 unit and the MMU2 circuits associated with the MD"k modules of the battery are encrypted, in order to preserve the confidentiality of the data exchanged.

[0127] In this way, communication between the MMU2 and BMU2 control units is ensured exclusively between two MC measuring units. Thus, the communication protocol between the MMU2 and BMU2 control units is implemented exclusively within the MC units. Communications can therefore be encrypted without having to provide the secret data necessary for encryption, stored by the MC units, to the manufacturer of the MMU2 or BMU2 units or to the integrator assembling the batteries. Furthermore, this communication takes place exclusively between a TXT transmit circuit and an RXT receive circuit of the CML2 circuit of an MC unit, which are specifically matched, particularly in terms of filtering. As a result, this communication is carried out optimally.

[0128] In one embodiment, each MCi measuring unit maintains an event log stored in a secure, immutable memory area. To this end, each MCi unit can be configured to acquire, for example periodically, measurements from sensors, perform calculations of operating parameters of the associated CLi cell based on the acquired measurements, such as the internal resistance of the CLi cell, and store these parameters in the secure memory area. These parameters may include, in particular, the number of cycles of the CLi cell, its operating time since commissioning, its internal resistance, its remaining capacitance, its remaining energy, the number of high and low voltage overshoots, and the number of high temperature threshold overshoots.

[0129] Each MCi measuring unit can also store in the secure memory area information about the CLi cell to which it is associated, such as its electrochemical system, the nature and origin of its active materials, the name of its manufacturer, the place and date of its manufacture, its manufacturing batch number, its nominal capacity, its life in number of cycles, its maximum, minimum and nominal operating and safety voltages, its maximum discharge current, its minimum and maximum temperatures in charge and discharge, and the battery assembly architecture (number of branches and number of cells per branch).

[0130] It will be readily apparent to those skilled in the art that the present invention is susceptible to various embodiments and applications. In particular, the invention is not limited to the message exchange described above. Indeed, in one embodiment, the management unit MMU, MMU1, MMU2 addresses the measurement units MC, MC', MC" individually by transmitting request messages containing a unique identifier of the measurement unit receiving the request message, the MCi units being configured to send a reply message only when they detect their identifier in the request message.

[0131] Other circuits can be implemented to apply voltage drops across the terminals of a battery cell or battery. For example, transistor T1 and the dissipative component R1 in MCi units can be replaced by a linear-mode MOSFET transistor controlled by the gate voltage. The same applies to transistor M1 and resistor R2. To perform cell balancing, the transistor can be controlled to divert current, for example, for a predefined fixed duration. Battery cell balancing can thus be carried out in successive stages.

Claims

CLAIMS 1 . Battery (BT, BT1) comprising: a plurality of cells (CLi), each cell comprising two connection terminals (CTH, CTL) for connecting to other cells and a measuring unit (MCi, MC, MC') integrated into the cell and connected to the cell connection terminals; several branches (BRj) connected in parallel between respective positive branch terminals (BTHj) and an external negative terminal (PTL) of the battery; each branch comprising several modules (MDk) connected in series by module positive (MTH) and negative (MTL) terminals; and a battery management unit (BMU) connected to the positive branch terminals, to external positive terminals (PTH1, PTH2) of the battery and to the external negative terminal of the battery; each module comprising: several branches (RMg) connected in parallel between respective positive branch terminals (RTHg) and a module negative terminal (RTL); each branch comprising several cells from the plurality of cells.connected in series by the cell connection terminals, and a module management unit (MMU) connected to the positive branch terminals, and to the positive and negative terminals of the module, the module management unit comprising a first communication circuit for communicating with the cell measurement units of the module and a second communication circuit for communicating with the battery management unit.

2. Battery according to claim 1, wherein the management unit (MMU1, MMU2) of each module (MD', MD") and each measuring unit (MC') of each module are configured to: transmit by the module's management unit a request message (FR1) in a modulated form by applying pulse bursts in the form of voltage drops between the positive and negative terminals (RTHg, RTL) of the branch; receive the request message by each of the module's measuring units, by demodulating the pulse bursts between the cell terminals to which the measuring unit is connected;to emit by each measuring unit of the module in response to the request message, a response message (CFR_J) in a modulated form by applying pulse bursts in the form of voltage drops between the terminals (CTH, CTL) of the cell to which the measuring unit is connected, during a respective time slot allocated to the measuring unit, the response message containing data from a measurement of an operating parameter of the cell; and to receive the response message by the module management unit, by demodulating the pulse bursts detected on the battery terminals.

3. Battery according to claim 2, wherein each unit of measurement (MC') is configured to: measure a voltage across the terminals (CTH, CTL) of the cell (CLi), and to derive current across the cell terminals by the unit of measurement for a balancing time which can be fixed, when the measured voltage is greater than a set value, in order to balance the cell with the other cells of the battery.

4. Battery according to claim 2 or 3, wherein the voltage drops are applied by the management unit (MMU1, MMU2) or by each of the measuring units (MC'), by controlling a transistor (M1, T1) connected to the branch terminals (BTHg, BTL), and respectively to the terminals (CTH, CTL) of each cell (CLi).

5. Battery according to any one of claims 2 to 4, wherein the voltage drops generated by each of the measurement units (MC') of the module to emit a reply message have an amplitude of a few tens of millivolts.

6. Battery according to any one of claims 2 to 5, wherein the measurement units (MCi) are synchronized to a detection instant of a first voltage drop upon receipt of a request message.

7. Battery according to any one of claims 2 to 6, wherein each module management unit (MMU1, MMU2) is configured to: detect by the module management unit (MMU1, MMU2) that one of the cells (CLi) of the battery is faulty on the basis of a failure to receive the response message (CFR_J) from the cell measurement unit (MC'), or on the basis of a cell operating parameter measurement data received in the response message from the cell measurement unit, and if a cell fault is detected, control a switch (SWg) to disconnect a branch (RMg) of series-connected cells, to which the faulty cell belongs.

8. Battery according to any one of claims 1 to 7, wherein several cell operating parameters (CLi) are measured and transmitted by each measuring unit (MCi), the cell operating parameters comprising at least one of the following parameters: a voltage across the cell terminals, a cell temperature, a current through the cell, an internal cell resistance, and a pressure in the cell.

9. Battery according to any one of claims 1 to 8, wherein each management unit (MMU, MMU1) communicates with the battery management unit (BMU) via a dedicated data transmission bus (DBS, DBj) or wireless links.

10. Battery according to any one of claims 1 to 8, wherein each management unit (MMU2) communicates with the battery management unit (BMU2) via electrical links connecting the module terminals (MTH, MTL) together to form the branches and with the branch terminals (BTHj) and the negative battery terminal (PTL).

11. Battery according to claim 10, wherein the management unit (MMU2) of each module and the battery management unit (BMU2) are configured to: transmit by the battery management unit a request message (FR1) in a modulated form by applying pulse bursts in the form of voltage drops between the positive and negative terminals (BTHj, BTL) of a branch (BRj) to which the module is connected; receive the request message by each of the management units of the modules belonging to the branch, by demodulating the pulse bursts between the terminals of the module to which the module management unit is connected;to emit by each module management unit of the branch, in response to the request message, a response message (CFR_J) in a modulated form by applying pulse bursts in the form of voltage drops between the terminals (MTH, MTL) of the module to which the module management unit is connected, during a respective time slot allocated to the module management unit, the response message containing data from a measurement of an operating parameter of the module; and to receive the response messages by the battery management unit, by demodulating the pulse bursts detected on the terminals of the branch.

12. Battery according to any one of claims 1 to 11, wherein each module (MD, MD') management unit (MMU, MMU1, MMU2) includes a power switch (SWg) per branch (RMg) to disconnect one of the branches when a cell in the branch is detected as faulty.

13. Battery according to any one of claims 1 to 12, wherein each measuring unit (MCi) comprises a wake-up circuit (WU) configured to detect a voltage drop across the cell terminals (CTH, CTL), and activate a processing unit (UCC) of the measuring unit upon detection of the voltage drop, the management unit (MMU1, MMU2) being configured to generate the wake-up voltage drop.

14. Battery according to any one of claims 1 to 13, wherein each unit of measurement (MCi, MC', MC") is realized in the form of a miniaturized integrated component embedded in one of the cells (CLi) of the battery (BT).

15. Battery according to claim 14, wherein: each module management unit (MMU1, MMU2) integrates a measurement unit (MC") in the form of an integrated component for communicating with the module's measurement units (MC', MC") (MD"k), and / or The battery management unit (BMU2) and each module management unit (MMU2) incorporate a measurement unit (MC") in the form of an integrated component so that the battery management unit can communicate with the battery management units and vice versa.

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