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    • 专利摘要:
    A battery architecture based on the paralleling of n branches of battery modules associated with a DC / DC converter, the assembly being controlled by an intelligent controller. It is thus possible to isolate a branch, to connect it to the DC / DC converter and then to perform charging or discharging operations of this branch using the available power of the battery modules of the n-1 other branches. The n-1 other branches remain at the same time available to a user. The isolated branch is then reconnected to the other branches to rebuild the initial system. This architecture makes it possible to carry out operations such as a balancing of voltages between modules, a determination of state of charge, a measurement of capacity. This architecture comprises a single bidirectional DC voltage step-down DC / DC converter, able to provide in each branch individually the load and discharge of the module or modules of said branch.
    公开号:FR3074374A1
    申请号:FR1761262
    申请日:2017-11-28
    公开日:2019-05-31
    发明作者:Philippe LAFLAQUIERE；Younes JAOUI
    申请人:SAFT Societe des Accumulateurs Fixes et de Traction SA；
    IPC主号:
    专利说明:

    ARCHITECTURE OF BATTERY MODULES CONNECTED IN PARALLEL TECHNICAL FIELD
    The technical field of the present invention is that of the design of architectures of battery modules connected in parallel. The technical field is also that of monitoring and controlling the operation of battery modules within an architecture comprising several branches of battery modules connected in parallel.
    STATE OF THE ART
    A battery module typically comprises a plurality of electrochemical cells, also called electrochemical generators or accumulators, electrically connected, and united within the same container forming the envelope of the module. The elements discharge and supply electrical energy to an electrical consumer. The battery module can be charged by a charger to increase the amount of electrical energy stored in each element of the module.
    During the operation of a battery module, it is known to periodically measure certain parameters of its operation, such as its temperature, the intensity of the current flowing through it and the voltage of each of the elements. To this end, the battery module is associated with an electronic management system often referred to by the acronym BMS for "Battery Management System" in English. If one of the module's operating parameters or one of the module's elements falls outside a predetermined range, the electronic management system informs the user. This then intervenes on the module and performs a so-called maintenance operation. This maintenance operation may for example consist of putting the module to rest or balancing the tensions of the module elements. Voltage balancing consists in homogenizing the voltages of the different elements of the module. It allows, by charging or discharging the element or elements whose voltage differs significantly from that of the other elements of the module, to bring this or these elements to a voltage close to that of the other elements of the module.
    FIG. 1 represents a conventional architecture in which a battery module (M) sends information (COM) to a BMS relating to the operation of the module. The BMS can, depending on this information, act on the charger (C) or on the electric consumer (L), for example by stopping the charging or discharging of the battery module, or by charging or discharging the battery module , or by performing a balancing operation on the module elements or by determining the state of charge of the module. The user must then disconnect the module from the electrical consumer or the charger, and perform the requested operation.
    Several battery modules can be connected in series to increase the voltage required by the electrical consumer. In addition, several branches each comprising one or more battery modules connected in series can be connected in parallel in order to increase the intensity of the current necessary for the operation of the electric consumer. It is therefore known to manufacture a system comprising several branches in parallel, each branch comprising one or more battery modules connected in series. It is a series-parallel system. However, different battery modules, although manufactured to be identical, may have slightly different characteristics, for example a charge acceptance or a different self-discharge, then leading to different electrical performances between modules. Thus, when charging multiple battery modules in series, they may not all charge at the same speed. The voltages at the terminals of the different modules can vary from one module to another. If the voltage of one of the modules in charge reaches its stop voltage more quickly, the charging of this module will stop before the other modules in series are fully charged. In order to optimize the charge and therefore the state of charge of a battery module within a branch, it is known to carry out a balancing of the module.
    In addition, within the same battery module, an element may have characteristics different from those of the other elements of the module, thus leading to different electrical performances. In this case, this element is balanced against the other elements of the module.
    Balancing a battery module may require electrically isolating the branch in which said module is located, or may require a specific charge from the branch in which said module is located. However, the current supply to the electric consumer is interrupted. Balancing is therefore a source of service interruption for the end user. The problem therefore arose of being able to isolate one of the branches in parallel with a system of battery modules, without disturbing the operation of the other branches. These other branches must be able to remain available to the user, that is to say, continue to supply the current required by the operation of the electric consumer.
    The documents CN 205248399, CN 102684273 and EP 2658070 describe architectures comprising several branches in parallel, each branch comprising at least one battery module. It can be noted that each branch comprises a bidirectional DC / DC converter allowing the charging or discharging of the battery module. These architectures use as many DC / DC converters as there are branches, which makes them complex and expensive. We are therefore looking for a way to simplify these architectures.
    There is therefore a need for an architecture comprising several branches in parallel, each branch comprising one or more battery modules connected in series, this architecture having to allow isolation of one of the branches without interruption of service, and having to be simple in design. and inexpensive.
    SUMMARY OF THE INVENTION
    To this end, the invention provides a device for controlling battery modules, said device comprising at least two branches connected in parallel, each branch comprising one or more battery modules connected in series, each branch being able to be connected to an internal circuit or to an external circuit, said external circuit being able to:
    - charging the battery modules of said at least two branches by a charger,
    - discharging the battery modules of said at least two branches in an electrical consumer;
    said internal circuit being able to:
    - charging the battery module (s) of one of the branches by the battery module (s) of one or more other branch (s) and at
    - discharging the battery module (s) from one of the branches in one or more battery modules from one or more other branch (s);
    said device further comprising:
    - a branch controller by branch, able to control:
    - the connection to the external circuit and the disconnection to the external circuit of the branch with which the branch controller is associated, and
    - connection to the internal circuit and disconnection from the internal circuit of the branch with which the controller is associated, and
    - a single DC / DC step-down converter, bidirectional in current, whose input is connected to the external circuit and the output is connected to the internal circuit, able to ensure in each branch individually the charge and discharge of the modules of said branch.
    The device according to the invention makes it possible to electrically isolate a branch containing one or more battery modules, to connect it to the DC / DC converter then to carry out the maintenance operation of this branch, while using the power available by the modules n-1 branch battery. The branch which has been isolated is then reconnected to the other branches in parallel to reconstitute the initial system.
    The invention makes it possible to carry out operations such as balancing one or more modules of a branch, determining the state of charge (“State Of Charge” SOC) of one or more modules of a branch, a measure of the capacity of one or more modules of a branch, without creating unavailability of service for a user.
    One of the characteristics of the device according to the invention is that it uses a single DC / DC step-down, step-up current-converter, which ensures for each branch individually, that is to say one branch after another. , the maintenance operation of the module or modules of said branch.
    According to one embodiment, the branch controller is an electronic system allowing the measurement of the various operating parameters of a battery module, such as the voltage, the current, the temperature, the state of charge and the state of health. .
    According to one embodiment, the device further comprises a main controller and each branch controller is able to warn the main controller when an operating parameter of a battery module of the branch leaves a predetermined range of values. The main controller can control the operation of the DC / DC converter to allow charging or discharging of the battery module (s) of one of the branches.
    According to one embodiment, one or more battery modules comprises an electrochemical cell of the lithium-ion type. The cathodic active material of the electrochemical element can be a mixture comprising:
    a) a lithiated oxide of transition metals containing one or more elements chosen from nickel, cobalt, manganese and aluminum;
    b) a lithiated phosphate of at least one transition metal, the surface of which is at least partially covered with a carbon layer, said phosphate comprising either iron or manganese, or iron and manganese.
    The subject of the invention is also a method for checking battery modules, said method comprising the steps of:
    a) connection of all the branches of the device to the external circuit;
    b) disconnection of the external circuit from one of the branches of the device or connection to the internal circuit of one of the branches (Bi) of the device;
    c) carrying out a maintenance operation of the battery module or modules of said branch;
    d) disconnection of the internal circuit of said branch when, in step b), said branch has been connected to the internal circuit;
    e) reconnection of said branch to the external circuit.
    According to one embodiment, the maintenance operation of step c) comprises a phase of resting the battery module or modules of said branch.
    According to one embodiment, the maintenance operation of step c) consists of a partial or complete charge of the battery module (s) of said branch by the battery module (s) of another branch or of the other branches.
    According to one embodiment, the DC / DC converter converts the voltage of the battery module or modules of the other branch or of the other branches into a charging voltage of the module or modules of said branch.
    According to one embodiment, the maintenance operation of step c) consists of a partial or complete discharge of the battery module (s) of said branch in the battery module (s) of another branch or of the other branches.
    According to one embodiment, the DC / DC converter converts the voltage of the battery module or modules of said branch into a charging voltage of the module or modules of another branch or of the other branches.
    According to one embodiment, during steps b) to e), the battery module or modules not undergoing the maintenance operation, are connected to the external circuit.
    According to one embodiment,
    - step b) is initiated when a branch controller detects that an operating parameter of the battery module (s) of said branch leaves a predetermined range of values; and
    - steps d) and e) are initiated when a branch controller detects that an operating parameter of the battery module or modules of said branch enters a predetermined range of values.
    According to one embodiment, the maintenance operation of step c) is chosen from:
    - balancing between the voltages of the battery modules of the same branch,
    - a determination of the state of charge of the battery module or modules of the same branch,
    - a determination of the capacity of the battery module or modules of the same branch,
    - a determination of the state of health of the battery module (s) in the same branch.
    BRIEF DESCRIPTION OF THE FIGURES
    FIG. 1 represents a conventional architecture comprising a battery module (M) and a device (BMS) for monitoring the operation of the battery module.
    FIG. 2 represents an architecture according to a first embodiment of the invention in which each branch controller (BMSi) controls the connection of the branch (Bi) to which it is associated with the internal circuit (CI) or the external circuit ( CE) and each branch controller controls the disconnection of the branch (Bi) from the internal circuit (CI) or from the external circuit (CE). It is a decentralized architecture.
    FIG. 3 represents an architecture according to a second embodiment in which a main controller (MBMS) controls each branch controller (BMSi) the connection of the branch (Bi) to which it is associated with the internal circuit (CI) or the external circuit (CE) and controls the disconnection of the branch (Bi) of the internal circuit (CI) or of the external circuit (CE). It is a centralized architecture.
    DETAILED DESCRIPTION
    The term “battery module” or “module” denotes in the following an electrochemical cell or several electrochemical cells connected in series or in parallel or in parallel-series or in series-parallel, united within a same container forming the enclosure of the module, each element being equipped with devices necessary for the electrical connection with the other elements of the module, for example in the form of metal bars (busbar), devices for measuring the operating parameters of the element (temperature, voltage , current) and possibly safety devices (valve, seal).
    The term “battery branch” or “branch” denotes in the following a battery module or several battery modules connected in series.
    The term "maintenance" can mean in the following one of the following operations:
    - putting one or more battery modules to rest;
    - partial or full charge of one or more battery modules; partial or full charge of one or more elements of a battery module;
    - partial or complete discharge of one or more battery modules; partial or complete discharge of one or more elements of a battery module;
    - determination of the state of charge (SOC) of one or more battery modules; determination of the state of charge of one or more elements of a battery module;
    - determination of the state of health (SOH) of one or more battery modules; determination of the state of health of one or more elements of a battery module;
    - determination of the residual capacity of one or more battery modules; determination of the residual capacity of one or more elements of a battery module;
    - balancing of the voltages of the battery modules of the same branch; balancing of the voltages of the elements of the same battery module.
    These examples of maintenance operations are given for information only and are not limiting on the definition of the term "maintenance".
    The device according to the invention will now be described in relation to FIG. 2.
    The system according to the invention comprises n battery branches connected in parallel, n being greater than or equal to 2. FIG. 2 shows a particular case of three branches Bi, Bi and B n connected in parallel.
    A branch includes one or more battery modules (Mi, M x ) connected in series.
    The assembly formed by the different branches in parallel is connected to the terminals of either a charger (C) or an electrical consumer (L). This assembly forms the so-called external circuit (CE). This allows either the charging of the battery modules by the charger, or the discharging of the battery modules in the electrical consumer.
    Each branch Bi comprises means for connecting or disconnecting said branch to the external circuit. This means can be a relay (RI). Apart from maintenance operations, a current flows in all branches of the external circuit, either to supply the electrical consumer by the module or modules of each branch, or to recharge the module or modules of branches by the charger.
    The device according to the invention comprises an internal circuit (IC) through which a charge or discharge current can flow during the maintenance operations of a given branch. Each branch includes means for connecting or disconnecting said branch to the internal circuit. This means can be a relay (R2).
    The device includes a step-down step-up DC / DC converter, whose input (E) is connected to the external circuit and whose output (S) is connected to the internal circuit. The DC / DC converter is bidirectional in current and allows the charging or discharging of the module (s) of the branch to which the maintenance operation relates. In a preferred embodiment, the converter is a “BuckBoost” type converter.
    The step-up step-down DC / DC converter can itself be made up of two DC / DC step converters in series, one serving as step-up converter, the other step-down converter. A capacitance can be inserted between these two converters in series, making it possible to vary the voltage between the two converters.
    The step-up step-down DC / DC converter can itself be made up of two DC / DC converters in parallel, one used to step up the voltage, the other to step down the voltage.
    The DC / DC converter can be of the isolated type or not.
    Each branch includes a branch controller (BMSi, BMSi, BMS n ). Typically, a branch controller is an electronic system for monitoring the main operating parameters of a battery module ("Battery Management System"). It periodically measures these parameters and warns the user when one of the parameters leaves a nominal operating range. Each branch controller acts on the means of connection or disconnection (RI) to the external circuit of the branch with which it is associated. Each branch controller also acts on the means of connection or disconnection (R2) to the internal circuit of the branch with which it is associated.
    According to a first embodiment illustrated in FIG. 2, the branch controllers communicate with each other via a communication bus. Each branch controller communicates with the DC / DC converter and manages the maintenance operation of the branch with which it is associated, based on the information exchanged with the branch controllers of the other branches. It is a decentralized management of maintenance operations.
    FIG. 3 illustrates an alternative embodiment in which the maintenance operations are managed centrally by a main controller (centralized architecture). The various components of the system are identified by the same reference signs as those used in FIG. 2. The difference between the system of FIG. 3 and that of FIG. 2 resides in the fact that in FIG. 3, each controller of branch communicates with a main controller ("Master Battery Management System" (MBMS)) via a communication bus. The main controller receives information from each branch controller and instructs each branch controller to connect or disconnect the branch with which it is associated, either to the external circuit or the external circuit, or to the internal circuit or the internal circuit. The main controller plays the role of coordinator between the branches. It also controls the DC / DC converter and provides information to the user on the operation of the system.
    The operation of the device according to the invention will now be described in relation to FIG. 2.
    a) Operation in nominal mode:
    Outside the maintenance periods, all the Bi, Bi and B n branches are connected to the external circuit. All RI relays in the external circuit are closed and all R2 relays in the internal circuit are open. The modules are either charged by the charger or discharged into the electrical consumer. No current flows through the DC / DC converter.
    b) Operation during a maintenance operation:
    Let Bi, the branch in which a module requires a maintenance operation. When the branch controller BMSi of the branch Bi detects that a maintenance operation is necessary on one of the modules Mi, M x of the branch Bi, the branch controller BMSi opens the relay RI of the external circuit of the branch Bi.
    Depending on the maintenance operation, either the RI relay remains open, or the Bi branch controller closes the R2 relay to connect the Bi branch module (s) to the internal circuit. The RI relay remains open in the event that the maintenance operation consists of simply putting the module (s) from the Bi branch to rest. Relay R2 closes if the maintenance operation consists of charging or discharging the module (s) from the Bi branch. The branch controller controls the DC / DC converter so that it initiates a charge or a discharge of the module or modules of the Bi branch.
    During the charging of the module (s) of the Bi branch by the modules of the n-1 branches, the RI relays of the n-1 branches are closed. The modules of the n-1 branches continue to supply current to the electrical consumer by the external circuit and at the same time supply current to the input of the DC / DC converter to recharge the module or modules of the Bi branch. The output of the DC / DC converter supplies only the module or modules of the Bi branch because the relay R2 of the Bi branch is closed and the relays R2 of the n-1 branches are open.
    Preferably, the charge of the module or modules of the Bi branch is done by the modules of the n-1 branches. It is also possible to envisage a less favorable operating mode in which only a part of the n-1 branches participates in the charge of the module or modules of the branch Bi.
    If the maintenance operation consists of a discharge of the module (s) from the Bi branch, this discharge can occur either in the modules of the n-1 branches, or in the electrical consumer. During the discharge, the relay R2 of the branch Bi is closed and the relays RI of the n-1 branches are closed. The DC / DC converter is bidirectional in current and the connection which was used as output for maintenance consisting of a load now works as input. Conversely, the connection which used to be charged input now works at output. It is through this output that the current from the module (s) of the Bi branch discharges into the modules of the n-1 branches and / or into the electrical consumer. During the discharge of the module (s) from the Bi branch, the modules of the n-1 branches continue to supply the electrical consumer because the RI relays of the n-1 branches are closed.
    Preferably, the discharge of the module (s) from the Bi branch takes place in the modules of the n-1 branches. It is also possible to envisage a less favorable operating mode in which only a part of the n-1 branches participates in the discharge of the module or modules of the branch Bi.
    The device according to the invention only allows the maintenance operation to be carried out on one branch at a time. If several branches simultaneously require a maintenance operation, the sequencing is done so that there is always, for a device comprising n branches, at least n-1 branches connected to the external circuit. An algorithm is used to manage the priorities between the different branches: distributed synchronization with logical clocks, distributed synchronization using a token.
    During the maintenance operation, the BMSi branch controller performs a periodic measurement of the operating parameters of the branch module (s) and decides to stop the maintenance operation when the operating parameters are at 'within a predetermined range.
    c) Return to nominal operation:
    Before ordering the opening of relay R2, i.e. disconnecting the Bi branch from the internal circuit and ordering the closing of RI, i.e. connecting the Bi branch to the external circuit , the branch controller BMSi of the branch Bi ensures that the voltage of the branch Bi is sufficiently close to the voltage of the other n-1 branches connected in parallel. If this is not the case, the BMSi branch controller instructs the DC / DC converter to charge or discharge the Bi branch. Once the desired voltage has been reached, the branch controller BMSi closes the relay RI then opens the relay R2. The Bi branch is thus reconnected to the external circuit.
    The tension of the Bi branch can vary significantly from that of the n-1 other branches, not following a maintenance operation of the Bi branch which de facto causes an imbalance of this branch compared to the other branches but following by example to an extended phase of rest of the battery system. As the self-discharge rates of the modules may differ, the module voltages may diverge at the end of this prolonged rest phase. In this case, the BMSi branch controller will instruct the DC / DC converter to charge or discharge the Bi branch. Once the desired voltage has been reached, the BMSi branch controller will close the RI relay and then open the R2 relay. The Bi branch will thus be reconnected to the external circuit.
    The operation of the device illustrated in FIG. 3 will now be described. In this centralized embodiment, the main controller MBMS commands each branch controller BMSi to connect or disconnect the branch Bi with which it is associated, either to the internal circuit or to the external circuit.
    When a maintenance operation is necessary on the Bi branch:
    1 / The BMSi branch controller of the Bi branch informs the main MBMS controller thereof via a communication bus;
    2 / The main MBMS controller authorizes the BMSi branch controller of the Bi branch to open the RI relay of the Bi branch;
    3 / Depending on the maintenance operation desired by the BMSi branch controller of the Bi branch, the main MBMS controller decides to leave the Bi branch disconnected by leaving the RI relay open or to ask the branch controller of the Bi branch to close R2 for connection to the internal circuit. Depending on the operation desired by the Bi branch controller, the main controller drives the DC / DC converter to perform charges or discharges.
    It is the BMSi branch controller of the Bi branch who identifies when the maintenance operation is finished, and who informs the main controller. As for the decentralized control, before commanding the opening of the relay R2, therefore the disconnection of the branch Bi of the internal circuit, and the closing of the relay RI, therefore the connection of the branch Bi to the external circuit, the controller BMSi branch of the Bi branch ensures that the voltage of the Bi branch is close enough to the voltage of the other n-1 branches in parallel. If not, the BMSi branch controller of the Bi branch orders the DC / DC converter to load or unload the Bi branch. Once the desired voltage has been reached, the branch controller BMSi of the branch Bi closes the relay RI then opens the relay R2.
    As explained for the embodiment with a decentralized control, the device according to the invention only allows the maintenance operation to be carried out on one branch at a time. If several branches request a maintenance operation at the same time, the main controller is responsible for ensuring the sequencing so that there are always at least n-1 branches connected to the external circuit.
    As the Bi branch is no longer available during the maintenance operation, it is necessary that the service provided by the device can be provided by the n-1 other branches. Consequently, the battery modules are chosen so that they can provide a sufficiently high current which compensates for the drop in current linked to the disconnection of the Bi branch of the external circuit during the maintenance operation.
    Examples of maintenance operations to optimize the power and / or energy performance of battery modules will now be detailed.
    - It can be a question of putting the module (s) of the branch to rest. You can measure their no-load voltage after it has stabilized and you can reconnect the module (s) to the external circuit when their no-load voltage is within a predetermined value range.
    - It can be a balancing of one or more modules of the branch. During this balancing, the module (s) of the branch having a voltage significantly different from that of the other modules of this branch are subjected to either a partial discharge or a partial charge so as to homogenize the voltages of the modules of the branch. Balancing can also be performed to homogenize the voltages of the electrochemical cells within the same module. Indeed, certain technologies require a balancing charge periodically in order to homogenize the electrochemical elements and thus optimize the electrochemical capacity of the module.
    - It can be a complete discharge of the module (s) of the branch during which the modules are discharged until waiting for a predetermined stop voltage. This operation allows for example to calibrate their state of charge to 0%. We can thus measure the residual capacity of the module (s).
    - It can be a full charge of the module (s) of the branch during which the modules are loaded until waiting for a predetermined stop voltage. This operation allows for example to calibrate their state of charge to 100%.
    These charging or discharging operations make it possible to precisely determine the state of charge of the modules.
    - When the battery modules are used over a long period, for example under cycling conditions, the electrochemical cells gradually lose their capacity. It is necessary for the user to know this loss of capacity so as to be able to replace with a new module a module having too great a loss of capacity. The loss of capacity can only be known with precision by performing a charge / discharge cycle of the module.
    - Another case concerns the connection of a battery branch in parallel: to avoid excessive current draws and damaging for the batteries of the branch module (s) to be connected in parallel, it is necessary to adjust the battery voltages of the module (s) of said branch at a voltage close to that (s) of the module (s) of the other branches before it can be connected.
    In addition to avoiding service interruptions, the invention makes it possible to carry out maintenance operations either automatically or via remote control. It is no longer necessary to send maintenance personnel, which is currently the case when we want to carry out a capacity test, for example, or to reconnect a battery branch in a multi-branch system.
    In addition, when replacing a battery module in a branch, the voltage of the new battery module must be equal to that of the other modules in the branch before installing it. Currently, this requires charger / unloader tools to bring the voltage of the new module to the desired value. The invention eliminates this tool because it allows the user to bring the voltage of the branch modules to the same voltage as that of the module to be installed. Thus, the new module can be installed directly.
    The invention can be applied to any electrochemical cell technology. Mention may be made, without being limiting, of lead-acid elements, elements with an alkaline electrolyte, such as nickel-cadmium and nickel-metal hydride, lithium-ion elements. The device is particularly suitable for electrochemical cells whose charge profile includes an area in which the voltage does not vary in a proportional manner with the state of charge. These are elements whose charge profile is "flat" in a given range of charge states, that is to say that the voltage of the element increases little with the increase in the state of charge in this given range of charge states. Mention may be made of electrochemical elements, the cathodic active material of which comprises a phosphate lithiated from a transition metal. In this type of element, the variation of the no-load voltage as a function of the state of charge presents an area for a state of charge of between 30 and 90% in which the no-load voltage increases at least 10 times less rapidly in state of charge function only for a state of charge between 90 and 100%. Such elements are for example described in document EP-A-2 269 954.
    Charge management methods specifically adapted to lithium-ion electrochemical cells having a flat charge profile in a given range of charge states are for example described in documents EP-A-2 634 591 and EP-A- 3,017,497.
    The device according to the invention finds numerous applications in the fields of aeronautics, automotive, telecommunications, emergency lighting, and rail.
    EXAMPLES
    Examples of maintenance operations are described below.
    Example 1: calibration of the state of charge of a battery module placed in one of the branches in parallel of a system, said battery module comprising lithium-ion electrochemical cells in which the cathodic active material is based on a lithiated oxide of transition metals, the transition metals being nickel, cobalt and aluminum (active material of type NC A), or nickel, manganese and cobalt (active material of type NMC)
    The state of charge of a battery module comprising electrochemical cells whose cathodic active material is based on NCA or NMC is liable to drift for a long period of operation in charge / discharge cycling. In operation, the state of charge of a module is calculated based on the balance of ampere hours charged and discharged and the actual state of charge of the module may differ significantly from the state of charge calculated by this coulometry-based method. In order to know the actual state of charge of the module, it is necessary either to put the module to rest and to wait for the open circuit voltage to stabilize, or to impose a low discharge current for a period of up to 'to several minutes. Sometimes such conditions may not be encountered, especially when the battery system is used 24 hours a day.
    The device according to the invention makes it possible to remedy this problem, by allowing the main controller or the branch controller - depending on whether it is a centralized or decentralized architecture - to disconnect the branch containing the module for which it is desired to determine the actual state of charge. The measurement of the no-load voltage makes it possible, for example, to determine the actual state of charge of the module. Once this determination has been made, the main controller or the branch controller controls the charging or discharging of the branch so that the module voltage reaches a value close to that of the modules of the other branches. When the balance between the voltages is reached, the branch containing the module is reconnected to the external circuit. The operation is then repeated on the other branches.
    Example 2: capacity test
    In a typical use case, a battery module is never discharged to 0% of its state of charge, this in order to avoid the negative effects of extreme states of charge on the aging of the module. It is therefore not easy to have an accurate estimate of the real capacity of a module, except by performing a capacity test. This capacity test requires charging the module to its stop voltage to set the state of charge at 100%, then discharging the module to its stop voltage and measuring the discharged capacity. This test cannot be performed when the battery system is used 24 hours a day
    The device according to the invention makes it possible to remedy this problem, by allowing the branch controller or the main controller to disconnect the branch from the external circuit, connect it to the internal circuit and perform the charge / discharge cycle as described while the other branches remain connected to the external circuit to provide service to the user. Once the capacity test has been carried out, the branch controller or the main controller charges the branch to bring it to the same voltage level as the other branches, so that it can reconnect it to the external circuit.
    The procedure can be repeated on the other branches until the complete system has carried out its capacity check.
    Example 3: calibration of the state of charge and balancing on battery module comprising electrochemical cells having a "flat" charge profd on a given range of states of charge
    Some applications such as hybrid vehicles require charging / discharging in a given window of charge states, for example ranging from 30% to 70%, for reasons of performance and preservation of the life of the drums. The state of charge of a battery module comprising electrochemical elements whose cathodic active material has a "flat" charge profile drifts after several cycles relative to the state of charge estimated by coulometry. In addition, the electrochemical cells are unbalanced after a certain period due to their different self-discharge currents. A determination of the states of charge of the electrochemical cells and a comparison between the different values obtained makes it possible to detect whether certain cells must undergo balancing. However, the determination of the state of charge of this type of element with a “flat” charge profile can only be made by bringing the tension of these elements outside the flat zone of the charge profile, for example by charging above 90% state of charge. This means that the user must carry out an almost complete charge of the battery module, which can be problematic. Indeed, the user must have recourse to an external charger to reach at least 90% of state of charge. In addition, he must temporarily stop the operation of the system.
    The device according to the invention makes it possible to remedy this problem, by allowing the branch controller or the main controller to isolate a branch on an internal circuit so as to charge it above 90% state of charge, while the average state of charge of the other branches which remain connected to the external circuit is maintained between 30% and 70% to continue to supply the engine of the hybrid vehicle.
    Once the balancing has been carried out, the branch controller or the main controller controls the discharge of the branch in order to upgrade it from the other branches so that it can be reconnected to the external circuit. The operation is then repeated on the other branches.
    权利要求:
    Claims (15)
    [1" id="c-fr-0001]
    1. Battery module control device, said device comprising at least two branches (Bi, Bi, B n ) connected in parallel, each branch comprising one or more battery modules (Mi, M x ) connected in series, each branch being able to be connected to an internal circuit (CI) or to an external circuit (CE), said external circuit being capable of:
    - charging the battery modules of said at least two branches by a charger (C),
    - discharging the battery modules of said at least two branches in an electrical consumer (L);
    said internal circuit being able to:
    - charging the battery module (s) of one of the branches by the battery module (s) of one or more other branch (s) and at
    - discharging one or more battery modules from one of the branches in one or more battery modules from one or more other branch (es);
    said device further comprising:
    - a branch controller (BMSi, BMSi, BMS n ) per branch, able to control:
    - the connection to the external circuit and the disconnection to the external circuit of the branch with which the branch controller is associated, and
    - connection to the internal circuit and disconnection from the internal circuit of the branch with which the controller is associated, and
    - a single DC / DC step-down converter, bidirectional in current, whose input is connected to the external circuit and the output is connected to the internal circuit, able to ensure in each branch individually the charge and discharge of the modules of said branch.
    [2" id="c-fr-0002]
    2. Device according to claim 1, in which the branch controller is an electronic system allowing the measurement of the various operating parameters of a battery module, such as the voltage, the current, the temperature, the state of charge and the 'health.
    [3" id="c-fr-0003]
    3. Device according to one of claims 1 to 2, further comprising a main controller (MBMS) and each branch controller (BMSi) is able to warn the main controller when an operating parameter of a battery module of the branch leaves of a predetermined range of values.
    [4" id="c-fr-0004]
    4. Device according to claim 3, wherein the main controller controls the operation of the DC / DC converter to allow charging or discharging of the battery module or modules of one of the branches.
    [5" id="c-fr-0005]
    5. Device according to one of the preceding claims, in which one or more battery modules comprises an electrochemical element of the lithium-ion type.
    [6" id="c-fr-0006]
    6. Device according to claim 5, in which the cathodic active material of the electrochemical element is a mixture comprising:
    a) a lithiated oxide of transition metals containing one or more elements chosen from nickel, cobalt, manganese and aluminum;
    b) a lithiated phosphate of at least one transition metal, the surface of which is at least partially covered with a carbon layer, said phosphate comprising either iron or manganese, or iron and manganese.
    [7" id="c-fr-0007]
    7. Method for checking battery modules, said method comprising the steps of:
    a) connection of all the branches (Bi, Bi, B n ) of the device according to one of the preceding claims to the external circuit;
    b) disconnection of the external circuit (CE) from one of the branches (Bi) of the device or connection to the internal circuit (CE) of one of the branches (Bi) of the device;
    c) carrying out a maintenance operation of the battery module ( s ) (Mi, M x ) of said branch (Bi);
    d) disconnection of the internal circuit of said branch when, in step b), said branch has been connected to the internal circuit;
    e) reconnection of said branch to the external circuit.
    [8" id="c-fr-0008]
    8. The method of claim 7, wherein the maintenance operation of step c) comprises a phase of resting the battery module or modules of said branch.
    [9" id="c-fr-0009]
    9. The method of claim 7, wherein the maintenance operation of step c) consists of a partial or complete charge of the battery module (s) of said branch (Bi) by the battery module (s) of another branch or other branches.
    [10" id="c-fr-0010]
    10. The method of claim 9, wherein the DC / DC converter converts the voltage of the battery module (s) of the other branch or other branches into a charging voltage of the module (s) of said branch (Bi).
    [11" id="c-fr-0011]
    11. The method of claim 7, wherein the maintenance operation of step c) consists of a partial or complete discharge of the battery module (s) of said branch (Bi) in the battery module (s) of another branch or other branches.
    [12" id="c-fr-0012]
    12. The method of claim 11, wherein the DC / DC converter converts the voltage of the battery module or modules of said branch (Bi) into a charging voltage of the module or modules of another branch or other branches.
    [13" id="c-fr-0013]
    13. Method according to one of claims 7 to 12, wherein during steps b) to e), the battery module or modules not undergoing the maintenance operation, are connected to the external circuit.
    [14" id="c-fr-0014]
    14. Method according to one of claims 7 to 13, in which:
    - step b) is initiated when a branch controller (BMSi) detects that an operating parameter of the battery module or modules of said branch (Bi) leaves a predetermined range of values;
    - steps d) and e) are initiated when a branch controller detects that an operating parameter of the battery module or modules of said branch enters a predetermined range of values.
    [15" id="c-fr-0015]
    15. Method according to claim 7, in which the maintenance operation of step c) is chosen from:
    - balancing between the voltages of the battery modules of the same branch,
    - a determination of the state of charge of the battery module or modules of the same branch,
    - a determination of the capacity of the battery module or modules of the same branch,
    - a determination of the state of health of the battery module (s) in the same branch.
    1/1
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    同族专利:
    公开号 | 公开日
    EP3490099A1|2019-05-29|
    FR3074374B1|2019-10-18|
    US20190165584A1|2019-05-30|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
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    KR101773698B1|2015-01-13|2017-08-31|주식회사 엘지화학|Method for preparing positive electrode composition of lithium secondary battery, and positive electrode and lithium secondary battery prepared by using the same|WO2020028454A1|2018-07-31|2020-02-06|Frederick Winters|Battery management system|
    GB2578090B|2018-10-01|2021-08-04|Ge Aviat Systems Ltd|System and method for maintaining power source|
    CN110816356B|2019-09-27|2021-09-14|三峡大学|Power battery charging electrical control system and method|
    US20210135173A1|2019-10-30|2021-05-06|Saft America|Battery modules and systems having a plurality of graphite, silicon and/or silicon oxide cells and atitanate oxide cell|
    US20210384527A1|2020-06-08|2021-12-09|Saft America|Lithium-ion primary pouch battery|
    CN113276691B|2021-07-26|2021-10-12|西安快舟机电科技有限公司|Energy storage module, vehicle-mounted charging system and charging method thereof|
    法律状态:
    2018-11-07| PLFP| Fee payment|Year of fee payment: 2 |
    2019-05-31| PLSC| Publication of the preliminary search report|Effective date: 20190531 |
    2019-11-04| PLFP| Fee payment|Year of fee payment: 3 |
    2020-11-03| PLFP| Fee payment|Year of fee payment: 4 |
    2021-11-05| PLFP| Fee payment|Year of fee payment: 5 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1761262|2017-11-28|
    FR1761262A|FR3074374B1|2017-11-28|2017-11-28|ARCHITECTURE OF BATTERY MODULES CONNECTED IN PARALLEL|FR1761262A| FR3074374B1|2017-11-28|2017-11-28|ARCHITECTURE OF BATTERY MODULES CONNECTED IN PARALLEL|
    US16/201,285| US20190165584A1|2017-11-28|2018-11-27|Architecture of battery modules connected in parallel|
    EP18208767.6A| EP3490099A1|2017-11-28|2018-11-28|Architecture of battery modules connected in parallel|
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