Method for communication between battery modules of a power supply and associated devices

Abstract

Method of communication between battery modules of a power supply and associated devices The present invention relates to a method of communication between battery modules (MB1, MB2, MB3) of a power supply (12) also comprising a communication network (24) between the battery modules (MB1, MB2, MB3), the method comprising: - a self-identification phase of the battery modules (MB1, MB2, MB3) comprising, for each battery module (MB1, MB2, MB3): - a step of allocating to the battery module (MB1, MB2, MB3) an identifier from among the available identifiers, - a step of memorizing that the identifier allocated to the battery module (MB1, MB2, MB3) considered is unavailable, - a communication phase between the battery modules (MB1, MB2, MB3) comprising: - a step of sending a message including the identifier allocated by one of the battery modules (MB1, MB2, MB3) on the communication network (24).Figure for the abbreviation: figure 2.

Description

Title of the invention: Method of communication between battery modules of a power supply and associated devices

[0001] The present invention relates to a method for communicating between battery modules of a power supply. The present invention also relates to an associated power supply and system.

[0002] Batteries are increasingly used to power numerous loads in ever-widening application areas. This leads to increasingly significant energy needs, which are met by multiplying the number of modules making up the battery.

[0003] However, in order for such modules positioned in parallel and / or in series to function correctly, it is necessary to ensure good communication between the different modules.

[0004] For this, it is known to identify each module by a unique identifier assigned for the entire life of the battery at the place of manufacture.

[0005] This nevertheless poses a problem during maintenance because it is difficult to identify the module containing this identifier because this involves carrying out in-situ tests to determine this module.

[0006] There is therefore a need for a method of communication between battery modules of a power supply which allows easier maintenance.

[0007] For this purpose, the description describes a method of communication between battery modules of a power supply, the power supply also comprising a communication network between the battery modules, the communication method comprising a phase of self-identification of the battery modules, the self-identification phase comprising, for each battery module, a step of allocating to the battery module an identifier from among the available identifiers of a list of identifiers, the allocation step being implemented by the battery module in question. The self-identification phase comprising a step of storing that the identifier allocated to the battery module in question is unavailable.The communication method also comprises a communication phase between the battery modules, the communication phase comprising a step of sending a message by one of the battery modules on the communication network, the message comprising the identifier allocated to said battery module.

[0008] According to particular embodiments, the communication method has one or more of the following characteristics, taken in isolation or in all technically possible combinations:

[0009] - each battery module comprises a communication unit (18) with a another battery module, the other battery module preferably being the battery module closest to the battery module in question, the self-identification phase comprising, for each battery module, a step of sending a communication signal by the communication unit of the battery module in question to the other battery module, the communication signal being modified when the allocation and storage steps have been implemented.

[0010] - each communication unit comprises a signal generator and a link wired between the two battery modules.

[0011] - the communication signal is a signal having a high state and a low state, the state bottom being sent when the allocation and storage steps have been implemented.

[0012] - the communication signal comprises at least two states, each state corresponding to an oscillation frequency between two respective values, one of the oscillation frequencies preferably being zero.

[0013] - the storage step comprises sending a message from the battery module considered, the message comprising the identifier allocated to the battery module considered,

[0014] - the self-identification phase comprises a step of sending an activation signal of each of the battery modules, the self-identification phase being implemented each time the power supply is started.

[0015] - the method comprises, for each battery module, a comparison step of the identifier obtained at the end of the implementation of the self-identification phase with the identifier obtained from the implementation of the self-identification phase during a previous start, and a step of changing information relating to the battery module according to the result of the comparison, the information relating to the battery module being, for example, the position of the battery module in the power supply.

[0016] The description also describes a power supply comprising battery modules, a communication network between the battery modules, the power supply being able to implement a phase of self-identification of the battery modules, the self-identification phase comprising, for each battery module, a step of allocating to the battery module an identifier from among the available identifiers of a list of identifiers, the allocation step being implemented by the battery module in question and a step of storing that the identifier allocated to the battery module in question is unavailable. The power supply is also able to implement a communication phase between the battery modules, the communication phase comprising a step of sending a message by one of the modules battery on the communication network, the message including the identifier allocated to said battery module.

[0017] The description also relates to a system comprising such a power supply as previously described.

[0018] In the present description, the expression “suitable for” means indifferently “adapted for”, “adapted to” or “configured for”.

[0019] Characteristics and advantages of the invention will appear on reading the description which follows, given solely by way of non-limiting example, and made with reference to the appended drawings, in which:

[0020] - [Fig.l] [Fig.l] is a schematic representation of a system comprising a power supply comprising a set of battery modules,

[0021] - [Fig 2] [Fig 2] is a flowchart of an example implementation of a method of communication between the battery modules of [Fig.l], and

[0022] - [Fig.3] [Fig.3] is a set of graphs obtained by performing experimentally a method of communication between the battery modules of [Fig.l].

[0023] [Fig.l] illustrates a system 10 provided with a power supply 12 which serves to supply electrical energy to the system 10.

[0024] The system 10 is, for example, a vehicle, in particular a construction machine or a forklift.

[0025] Alternatively, the system 10 is an uninterruptible power supply system or an energy storage system.

[0026] The power supply 12 comprises a set 14 of battery modules.

[0027] The power supply 12 thus forms a battery.

[0028] A battery is a generic term for a set of electrical accumulators, called cells, connected together to create an electrical generator of desired voltage, power and capacity. A battery converts the electrical energy accumulated during the charging phase into chemical energy. The chemical energy consists of electrochemically active compounds arranged in the cell. The electrical energy is restored by converting the chemical energy into electrical energy during the discharge phase. The electrodes, arranged in a container, are electrically connected to current output terminals which ensure electrical continuity between the electrodes and an electrical consumer with which the cell is associated.

[0029] The battery module assembly 14 comprises, as its name indicates, a plurality of battery modules.

[0030] In the example of [Fig.l], for the sake of clarity, only three battery modules MB1, MB2 and MB3 are shown.

[0031] However, the number of battery modules can be as large as desired depending on the electrical energy requirement of the load to be supplied.

[0032] A battery module comprises one or more electrochemical elements electrically connected in series or in parallel. These electrochemical elements are arranged together in the same enclosure to form the battery module.

[0033] In the example described, the battery modules MB1, MB2 and MB3 are identical but this is not obligatory, the method detailed later being applicable to any type of battery module.

[0034] Each battery module MB 1, MB2 and MB3 has two states: a first state called the “on state” in which the battery module MB1, MB2 and MB 3 provides energy and a second state called the “off state” in which the battery module MB1, MB2 and MB3 does not provide energy.

[0035] The transition from one state to the other is, for example, achieved by using a device for switching off / on the respective terminals of each battery module MB1, MB2 and MB3 controlled by a control signal. In particular, the device may be a contactor and the control signal a logic signal.

[0036] According to the example described, each battery module MB1, MB2 and MB3 further has a third state, called standby state in which each battery module MB1, MB2 and MB3 is capable of communicating but does not provide energy.

[0037] The battery modules MB 1, MB2 and MB3 are ordered in a predefined order.

[0038] According to the example described, the battery modules MB1, MB2 and MB3 are positioned so that the first battery module MB1 is on the left in [Fig.l], the second battery module MB2 is in the middle in [Fig.l] and the third battery module MB3 is on the right in [Fig.l].

[0039] Each battery module MB 1, MB2 and MB3 comprises a communication unit 18 with another battery module MB1, MB2 and MB3.

[0040] In the example described, the other battery module is the battery module closest to the battery module in question, so that the other battery module is the neighbor of the battery module.

[0041] Each communication unit 18 is capable of sending a communication signal emitted by the battery module in question from the neighboring battery module.

[0042] In this case, this means more precisely that the first battery module MB1 is capable of communicating with the second battery module MB2 and that the second battery module MB2 is capable of communicating with the third battery module MB3.

[0043] Each communication unit 18 comprises a signal generator 20 and a wired connection 22 between the two battery modules MB1, MB2 and MB3.

[0044] The signal generator 20 is capable of generating a communication signal.

[0045] The communication signal is then transmitted by the wired link 22 which is here a simple cable connecting the two battery modules MB1, MB2 and MB3.

[0046] In this configuration, the battery modules MB1, MB2 and MB3 therefore form a chain in which each link is identical.

[0047] According to the example described, the communication signal is a signal having a high state and a low state. In this sense, the communication signal is a binary signal.

[0048] The power supply 12 also includes a communication network 24.

[0049] The communication network 24 is common to all the battery modules MB1, MB2 and MB3, that is to say that the communication network 24 is a communication network between the battery modules MB1, MB2 and MB3.

[0050] Each battery module MB 1, MB2 and MB3 is thus able to communicate with the other battery modules MB1, MB2 and MB3 by sending a signal.

[0051] In the following, a signal sent via the communication network 24 is called a “message” so as not to be confused with the communication signal transmitted by the communication unit 18.

[0052] Thus, a “message” is a message intended for all 14 of the battery modules connected to the communication network 24 while a “communication signal” is intended for a single battery module MB1, MB2 and MB3 (here the neighboring battery module).

[0053] According to the example described, the communication network 24 is a data bus, in particular a CAN data bus. The acronym CAN refers to the corresponding English name of “Controller Area Network” literally meaning local control network.

[0054] Alternatively, the communication network 24 is a LAN network. The acronym LAN refers to the corresponding English term “Local Area Network” literally meaning local network.

[0055] Each battery module MB 1, MB2 and MB3 further comprises its own controller 26.

[0056] Each controller 26 is capable of controlling the battery module MB1, MB2 or MB3 to which it belongs.

[0057] In particular, when the power supply 12 is started, the controller 26 is able to send an activation signal to the battery module MB1, MB2 or MB3.

[0058] The controllers 26 are, for example, synchronized by a central computer which is generally the computer of the system 10. Each controller 26 and the central computer then form a master-slave system. Communication between the controllers 26 and the central computer is done via the communication network 24.

[0059] The activation signal switches the battery module MB1, MB2 or MB3 in question from an off state to an on state.

[0060] The controller 26 also comprises a memory 28 accessible to the battery module MB1, MB2 or MB3 comprising a list of available identifiers.

[0061] An identifier is a code that uniquely identifies an element.

[0062] Each identifier in the list is therefore unique and the list of identifiers includes at least as many identifiers as there are battery modules MB1, MB2 and MB3.

[0063] The operation of the power supply 12 is now described with reference to [Fig 2] which corresponds to a flowchart of an example of implementation of a communication method between the battery modules MB1, MB2 and MB 3 of the power supply 12.

[0064] Initially (item 30 in [Fig 2]), it is assumed that the power supply 12 is in the off state.

[0065] In this state, each battery module MB1, MB2 and MB3 is in the off state and each communication signal is in the low state.

[0066] This is schematically represented in [Fig 2] by a diagram in element 30 in which each battery module MB1, MB2 and MB3 is represented by a square with an indication EE for off state and a link with the neighboring battery module MB1, MB2 and MB3 on which is marked EB for low state. The identifiers are not mentioned in this representation, which corresponds to the fact that at this stage, none of the battery modules MB1, MB2 and MB3 is associated with an identifier.

[0067] The method comprises a self-identification phase PI and a communication phase P2.

[0068] The PI self-identification phase comprises a step of sending an activation signal and, for each battery module, an allocation step, a storage step and a step of sending a communication signal.

[0069] During the step of sending an activation signal (element 32 in [Fig 2]), each controller 26 sends the activation signal to its respective battery module MB1, MB2 or MB3.

[0070] In response, each battery module MB1, MB2 and MB3 is put into the on state and each communication signal goes into the high state.

[0071] A similar operation could be obtained by using the previous standby state, this embodiment is not described below so as not to burden the description which follows.

[0072] This is shown schematically in [Fig 2] by a diagram in element 32 in which each battery module MB1, MB2 and MB3 has an indication EA for on state and a link with the neighboring module on which is marked EH for high state.

[0073] Then, the first battery module MB1 chooses an available identifier from the list of identifiers and assigns itself this identifier (see element 34 in [Fig 2]).

[0074] This operation is referred to as allocation in the following and the identifier thus chosen is called the first identifier ID1

[0075] In other words, the first battery module MB1 implements the allocation step to be associated with the first IDL identifier

[0076] With respect to the diagram in element 34, this is represented schematically by the indication ID1 which appears in element 34 of [Fig 2].

[0077] Once the first battery module MB 1 has allocated the first identifier ID1, the first battery module MB1 then sends a message over the communication network 24 to indicate that the first identifier ID1 is no longer available (see element 36 in [Fig 2]).

[0078] The second battery module MB2 and the third battery module MB3 are thus aware of the fact that the first identifier ID1 has already been allocated.

[0079] More precisely, the memory 28 of each controller 26 can thus implement the step of memorizing that the identifier allocated to the battery module MB1, MB2 and MB3 considered is unavailable.

[0080] For example, the identifier is deleted from the list of identifiers which then includes only two available identifiers.

[0081] During the step of sending a communication signal, the first battery module MB1 switches the communication signal to the low state (see element 38 in [Fig 2] in which the link between the first battery module MB1 and the second battery module MB2 has the indication EB, the other link continuing to have the indication EH).

[0082] This modification of the communication signal is implemented when the allocation and storage steps have been implemented.

[0083] Thus, the second battery module MB2 is informed by the first battery module MB1 that it can seek to self-identify, the first battery module MB1 having finished this operation.

[0084] The second battery module MB2 then performs the same operations as those just performed by the first battery module MB1.

[0085] More precisely, the second battery module MB2 implements the allocation step to be associated with an available identifier from the list of identifiers. This identifier is called second identifier ID2 (see element 40 in [Fig 2] in which the mention ID2 appears for the second battery module MB2).

[0086] During the storage step (see element 42 in [Fig 2]), the second battery module MB2 then sends a message on the communication network 24 to indicate that the second identifier ID2 is no longer available and the controller memory 26 updates the list of identifiers with this information.

[0087] Then, the second battery module MB2 turns the communication signal low to inform the third battery module MB3 that it can seek to self-identify, the second battery module MB2 having finished this operation (see element 44 in [Fig 2] in which the link between the second battery module MB2 and the third battery module MB3 includes the indication EB).

[0088] These steps are repeated until each battery module has been allocated an identifier.

[0089] In this example with three battery modules MB1, MB2 and MB3, the third battery module MB3 allocates itself a third available identifier ID3 (see element 46 in [Fig 2] in which the mention ID3 appears for the third battery module MB3).

[0090] At the end of the self-identification phase P2, each battery module MB 1, MB2 and MB3 is thus associated with a respective unique identifier.

[0091] The communication phase P2 can then be implemented.

[0092] During this communication phase P2, messages are exchanged between the battery modules MB1, MB2 and MB3.

[0093] The communication phase P2 comprises a step of sending a message by a battery module MB1, MB2 or MB3 on the communication network 24, the message comprising the identifier allocated to said battery module MB1, MB2 or MB3 (see element 48 in [Fig 2] where a case is illustrated where the first battery module MB1 sends a message M1 comprising the first identifier ID1 to the other battery modules which are here the second battery module MB2 and the third battery module MB3).

[0094] This makes it possible to know that the message comes from this particular battery module MB1, MB2 or MB3 and that this battery module MB1, MB2 or MB3 communicates useful information to the other battery modules MB1, MB2 and MB3.

[0095] Thus, the identifiers are sometimes referred to as node identifiers with reference to the corresponding English term “Node ID”.

[0096] The communication method which has just been described thus makes it possible to carry out self-identification of each of the battery modules MB1, MB2 and MB3 autonomously.

[0097] The fact that this identification is carried out in situ by an allocation carried out by each battery module MB1, MB2 or MB3 makes it easier to locate the battery module MB1, MB2 or MB3 in the power supply 12. This results in easier maintenance in the event of failure of one or more of the battery modules MB1, MB2 or MB3.

[0098] To further improve this ease of identification, it is advantageous for the PI self-identification phase to be implemented each time the power supply 12 is started and for any modification of the allocations to be taken into account.

[0099] For this, for each battery module MB1, MB2 or MB3, the method also comprises a step of comparing the identifier obtained at the end of the implementation of the self-identification phase PI with the identifier obtained from the implementation of the self-identification phase PI during a previous start-up and a step of changing information relating to the battery module MB1, MB2 or MB3 depending on the result of the comparison.

[0100] In such a case, the information relating to the battery module MB1, MB2 or MB3 is, preferably, the position of the battery module MB1, MB2 or MB3 in the power supply 12.

[0101] Information relating to the battery modules MB1, MB2 and MB3 as well as the allocations at a previous start are, for example, stored in the memory 28.

[0102] Other variants of the system 10 which has just been described are conceivable.

[0103] In particular, an example has been presented where the modification of the signal of communication when the allocation and storage steps have been implemented consists of switching from the high state to the low state. The reverse modification could be considered.

[0104] According to another embodiment, the at least two states of the communication signal correspond to a respective oscillation frequency between two values.

[0105] Advantageously, one could choose a zero frequency, that is to say an absence of oscillations. For example, for a two-state case, the other state would correspond to a frequency between 5 Hz and 15 Hz, for example equal to 10 Hz.

[0106] This corresponds to the case illustrated in [Fig.3] which is a representation of the graphs obtained experimentally during the implementation of the method of [Fig 2] for states of the communication signal corresponding to oscillation frequencies.

[0107] More precisely, the first graph 50 represents the temporal variation of the activation signal, the second graph 52 the temporal variation of the communication signal emitted by the first module MB1, the third graph 54 the temporal variation of the communication signal emitted by the second module MB2 and the fourth graph 56 the temporal variation of the communication signal emitted by the third module MB3.

[0108] The steps implemented in the case of [Fig.3] being similar to the case of [Fig 2], it is represented only in [Fig.3] the start of the activation and the end of the activation (deactivation) of the control signal of each battery module in denoting T1MX as the start and T2MX as the end for battery module X (X being here equal to 1, 2 or 3). As expected, only the end times T2MX differ from one battery module to another.

[0109] Such an embodiment makes it easier to detect the presence of a short circuit. Indeed, a short circuit corresponds to the case of a battery module MB1, MB2 or MB3 remaining frozen in a state. Therefore, if a signal varying in frequency is expected, the fact that the state remains frozen is the sign of the presence of a short circuit.

[0110] Furthermore, instead of a local implementation of the update, it could be envisaged to use a single memory accessible to each battery module.

Claims

1. Claims A method of communicating between battery modules (MB1, MB2, MB3) of a power supply (12), the power supply (12) also comprising a communication network (24) between the battery modules (MB1, MB2, MB3), the communication network (24) being common to all the battery modules (MB1, MB2, MB3), the communication method comprising: - a self-identification phase of the battery modules (MB1, MB2, MB3), the self-identification phase comprising, for each battery module (MB1, MB2, MB3): - a step of allocating to the battery module (MB1, MB2, MB3) an identifier from among the available identifiers of a list of identifiers, the allocation step being implemented by the battery module (MB1, MB2, MB3) considered, and - a step of memorizing that the identifier allocated to the battery module (MB1, MB2, MB3) considered is unavailable, - a communication phase between the battery modules (MB1, MB2, MB3), the communication phase comprising: - a step of sending a message by one of the battery modules (MB1, MB2, MB3) on the communication network (24), the message comprising the identifier allocated to said battery module (MB1, MB2, MB3), the self-identification phase comprising, a step of sending an activation signal for each of the battery modules (MB1, MB2, MB3), the self-identification phase being implemented each time the power supply (12) is started, the method comprising, for each battery module (MB1, MB2, MB3): - a step of comparing the identifier obtained at the end of the implementation of the self-identification phase with the identifier obtained from the implementation of the self-identification phase during a previous start, and - a step of changing information relating to the battery module (MB1, MB2, MB3) according to the result of the comparison, the information relating to the battery module (MB1, MB2, MB3) being, for example, the position of the battery module (MB1, MB2, MB3) in the power supply (12).

2. Communication method according to claim 1, wherein each battery module (MB1, MB2, MB3) comprises a communication unit (18) with another battery module (MB1, MB2, MB3), the other battery module (MB1, MB2, MB3) preferably being the battery module (MB1, MB2, MB3) closest to the battery module (MB1, MB2, MB3) in question, the self-identification phase comprising, for each battery module (MB1, MB2, MB3), a step of sending a communication signal by the communication unit (18) of the battery module (MB1, MB2, MB3) in question to the other battery module (MB1, MB2, MB3), the communication signal being modified when the allocation and storage steps have been implemented.

3. Communication method according to claim 2, wherein each communication unit (18) comprises a signal generator (20) and a wired connection (22) between the two battery modules (MB1, MB2, MB3).

4. A communication method according to claim 2 or 3, wherein the communication signal is a signal having a high state and a low state, the low state being sent when the allocating and storing steps have been implemented.

5. A communication method according to claim 2 or 3, wherein the communication signal comprises at least two states, each state corresponding to an oscillation frequency between two respective values, one of the oscillation frequencies preferably being zero.

6. Communication method according to any one of claims 1 to 5, wherein the storage step comprises sending a message from the battery module (MB1, MB2, MB3) in question, the message comprising the identifier allocated to the battery module (MB1, MB2, MB3) in question.

7. Power supply (12) comprising battery modules, a communication network (24) between the battery modules (MB1, MB2, MB3), the communication network (24) being common to all

8. the battery modules (MB1, MB2, MB3), the power supply (12) being suitable for implementing: - a self-identification phase of the battery modules (MB1, MB2, MB3), the self-identification phase comprising, for each battery module (MB1, MB2, MB3): - a step of allocating to the battery module (MB1, MB2, MB3) an identifier from among the available identifiers of a list of identifiers, the allocation step being implemented by the battery module (MB1, MB2, MB3) considered, and - a step of memorizing that the identifier allocated to the battery module (MB1, MB2, MB3) considered is unavailable, - a communication phase between the battery modules (MB1, MB2, MB3), the communication phase comprising: - a step of sending a message by one of the battery modules (MB1, MB2, MB3) on the communication network (24), the message comprising the identifier allocated to said battery module (MB1, MB2, MB3), the self-identification phase comprising a step of sending an activation signal for each of the battery modules (MB1, MB2, MB3), the self-identification phase being implemented each time the power supply (12) is started, the method comprising, for each battery module (MB1, MB2, MB3): - a step of comparing the identifier obtained at the end of the implementation of the self-identification phase with the identifier obtained from the implementation of the self-identification phase during a previous start, and - a step of changing information relating to the battery module (MB1, MB2, MB3) depending on the result of the comparison, the information relating to the battery module (MB1, MB2, MB3) being, for example, the position of the battery module (MB1, MB2, MB3) in the power supply (12). System (10) comprising a power supply (12) according to claim 7.

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