Active equalization circuit of battery module and control method

Abstract

The invention relates to an active equalization circuit of battery modules and a control method. The circuit is characterized in that each battery module is connected with a DC / DC boost module; the battery cluster level management unit receives the battery information sent by each battery module, calculates the current SOC of each battery module and the average value of each current SOC, and when it is judged that the maximum value of the difference value between the current SOC of any battery module and the average value exceeds a set range, sends the battery information to the battery cluster level management unit; charging / discharging control information of the battery module is generated and sent to the equalization control module; the equalization control module controls the closing of the corresponding contactor based on the charging / discharging control information and controls the starting of the DC / DC boosting module to charge / discharge the corresponding battery module; according to the invention, one battery cluster is configured with one DC / DC boost module, and when the energy storage system is charged, discharged or not charged and discharged, a single module is additionally charged or discharged, so that the charge consistency of the battery modules in the battery cluster is achieved, and active equalization is completed.

Description

Technical Field

[0001] The present invention relates to the field of battery control, and in particular to an active equalization circuit method for a battery module. Background Art

[0002] In the field of energy storage, battery systems are generally composed of single modules in series, and the modules are connected in series to form a battery cluster. This series connection will bring a barrel effect to the entire energy storage system, that is, when a certain cell is low or too high, the charging / discharging energy of the entire system will be reduced. When the power of a single cell is low, the system cannot release the remaining capacity. When the power of a single cell is too high, the system cannot charge more energy, resulting in a reduction in the overall available capacity of the system. At present, the solution for controlling the consistency of the power of cells in energy storage systems is generally passive balancing within the module, but the current of passive balancing is small, at the milliampere level, which will result in slow balancing speed and high heat generation. In addition, passive balancing consumes battery energy, which is not conducive to the efficient energy management of the energy storage system. At present, the solution for controlling the consistency of the power of battery modules in energy storage systems is parallel active balancing, which adopts a bidirectional DC / DC module in parallel with each module, and transfers the power of the battery module with more energy to the module with less energy by controlling the conduction of the DC / DC.

[0003] However, the active balancing circuit between modules is complex, and the matrix switch design is cumbersome and difficult to control. At the same time, each module needs to be equipped with a DC / DC module, which is costly. Moreover, transferring the excess power of one module to another or several other modules will cause the power of the transferred module to increase, causing the power of the new module to be unbalanced. Summary of the invention

[0004] In view of the technical problems existing in the prior art, the present invention provides an active balancing circuit and control method for a battery module, which adopts a battery cluster and a DC / DC boost module. When the energy storage system is charging, discharging, or not charging or discharging, the single module is additionally charged or discharged to achieve charge consistency of the battery modules in the battery cluster and complete active balancing.

[0005] According to a first aspect of the present invention, there is provided an active balancing circuit method for a battery module, comprising: a battery cluster-level management unit, a balancing control module, a DC / DC boost module, and a plurality of battery modules; The battery cluster-level management unit is connected to the balancing control module and each battery module in communication; each battery module is connected to the DC / DC boost module through each charging / discharging branch, each charging / discharging branch includes a contactor, and the balancing module is connected to each contactor and the DC / DC boost module in communication and control; The battery cluster management unit receives battery information sent by each battery module, calculates the current SOC of each battery module and the average value of each current SOC, and generates charge / discharge control information of the battery module and sends it to the balancing control module when it is determined that the maximum value of the difference between the current SOC of any battery module and the average value exceeds a set range; The balancing control module controls the corresponding contactor to close based on the charge / discharge control information and controls the DC / DC boost module to start charging / discharging the corresponding battery module.

[0006] Based on the above technical solution, the present invention can also make the following improvements.

[0007] Optionally, the battery cluster-level management unit determines that the difference between the module SOC of any battery module and the average value exceeds a set range, and generates the charge / discharge control information of the battery module, including: Calculate the maximum difference DSOCmax between each current SOC and the average value. When it is determined that the maximum difference DSOCmax exceeds the set threshold, determine whether the module SOC of the battery module corresponding to the maximum difference DSOCmax is lower than the average SOC. If so, generate charging control information, otherwise generate discharging control information.

[0008] Optionally, the process of charging the battery module of the balancing control module further includes: The balancing control module starts the DC / DC boost module in charging mode, calculates the real-time charging charge based on the integral of the charging current and the charging time, determines that the balancing is completed when the real-time charging charge reaches the maximum difference DSOCmax, and sends a stop balancing instruction to control the corresponding contactor to disconnect and the DC / DC boost module to shut down.

[0009] Optionally, the process of discharging the battery module of the balancing control module further includes: The balancing control module starts the DC / DC boost module in the discharge mode, calculates the real-time charge / discharge charge based on the integral of the discharge current and the discharge time, determines that the balancing is completed when the real-time discharge charge reaches the maximum difference DSOCmax, and sends a stop balancing instruction to control the corresponding contactor to disconnect and the DC / DC boost module to shut down.

[0010] Optionally, the battery module includes: a battery module level management unit; The battery module-level management unit collects voltage and current parameters of the battery module, and sends the collected parameters to the battery cluster-level management unit. The battery cluster-level management unit calculates the current SOC of each battery module based on the parameters.

[0011] Optionally, after the charging / discharging of the battery module is completed, the battery cluster-level management unit re-receives the battery information sent by each battery module, and updates the current SOC of each battery module.

[0012] Optionally, the battery cluster-level management unit updates the current SOC of each battery module and re-judges whether each battery module meets the preset equilibrium state requirement. If the requirement is not met, the battery cluster-level management unit recalculates and judges the current SOC of each battery module and the average value of each current SOC.

[0013] According to a second aspect of the present invention, there is provided a method for active balancing control of a battery module, comprising: Calculating the current SOC of each battery module and the average value of each current SOC, and generating charge / discharge control information of the battery module when it is determined that the maximum value of the difference between the current SOC of any battery module and the average value exceeds a set range; Each charging / discharging branch is respectively set to connect each battery module with the DC / DC boost module respectively, and the corresponding charging / discharging branch is controlled to be connected based on the charging / discharging control information and the DC / DC boost module is controlled to start charging / discharging the corresponding battery module.

[0014] Optionally, the process of generating the charge / discharge control information of the battery module includes: Calculate the maximum difference DSOCmax between each current SOC and the average value. When it is determined that the maximum difference DSOCmax exceeds the set threshold, determine whether the module SOC of the battery module corresponding to the maximum difference DSOCmax is lower than the average SOC. If so, generate charging control information, otherwise generate discharging control information.

[0015] Optionally, the process of charging / discharging the battery module further includes: The DC / DC boost module is started in the charge / discharge mode, and the real-time charge / discharge charge is calculated based on the integral of the charge / discharge current and the charge / discharge time. When the real-time charge / discharge charge reaches the maximum difference DSOCmax, it is determined that the balancing is completed, and a stop balancing instruction is sent to control the corresponding contactor to disconnect and the DC / DC boost module to shut down.

[0016] The present invention provides an active balancing circuit and control method for a battery module, which only requires a single DC / DC boost module to perform additional charging or discharging on a single battery module to achieve charge consistency of the battery modules in the system battery cluster and complete active balancing. It is not necessary to set a bidirectional DC / DC module for each battery module, which makes the control circuit simpler, and active balancing of the modules can still be performed when the system is in charging or discharging state. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A structural block diagram of an embodiment of an active balancing circuit for a battery module provided by the present invention; Figure 2 A flow chart of an active balancing control method for a battery module provided by the present invention. DETAILED DESCRIPTION

[0018] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0019] Figure 1 A structural block diagram of an embodiment of an active balancing circuit of a battery module provided by the present invention, such as Figure 1 As shown, the circuit includes: a battery cluster level management unit, a balancing control module, a DC / DC boost module and a plurality of battery modules; The battery cluster-level management unit is communicatively connected with the balancing control module and each battery module respectively; each battery module is connected with the DC / DC boost module via each charging / discharging branch, each charging / discharging branch includes a contactor respectively, and the balancing module is communicatively controlled with each contactor and the DC / DC boost module.

[0020] The battery cluster-level management unit receives the battery information sent by each battery module, and calculates the current SOC of each battery module and the average value of each current SOC. When it is determined that the maximum value of the difference between the current SOC and the average value of any battery module exceeds the set range, the charge / discharge control information of the battery module is generated and sent to the balancing control module.

[0021] The balancing control module controls the corresponding contactor to close based on the charge / discharge control information and controls the DC / DC boost module to start charging / discharging the corresponding battery module.

[0022] The present invention provides an active balancing circuit for a battery module, which uses a battery cluster to configure a DC / DC boost module. When the energy storage system is charging, discharging, or not charging or discharging, additional charging or discharging is performed on a single module to achieve charge consistency of the battery modules in the battery cluster and complete active balancing.

[0023] Example 1 Embodiment 1 of the present invention is an embodiment of an active balancing circuit of a battery module provided by the present invention, combined with Figure 1 It can be seen that the embodiment of the circuit includes: a battery cluster-level management unit, a balancing control module, a DC / DC boost module and a plurality of battery modules.

[0024] The battery cluster-level management unit is communicatively connected with the balancing control module and each battery module respectively; each battery module is connected with the DC / DC boost module via each charging / discharging branch, each charging / discharging branch includes a contactor respectively, and the balancing module is communicatively controlled with each contactor and the DC / DC boost module.

[0025] In specific implementation, a Hall current sensor can be added to the balancing circuit to communicate with the balancing control module through the CAN bus. The battery module-level management units and the battery module machine management unit and the battery cluster-level management unit can communicate using CAN or daisy chain communication. The battery cluster-level management unit and the balancing control module can communicate using CAN. The balancing control module and the DC / DC boost module can communicate using 485. The contactor's closing and opening are controlled by the I / O of the balancing control module.

[0026] The battery cluster-level management unit receives the battery information sent by each battery module, and calculates the current SOC of each battery module and the average value of each current SOC. When it is determined that the maximum value of the difference between the current SOC and the average value of any battery module exceeds the set range, the charge / discharge control information of the battery module is generated and sent to the balancing control module.

[0027] In a possible implementation manner, the battery module includes: a battery module-level management unit.

[0028] The battery module-level management unit collects the voltage and current parameters of the battery module, and sends the collected parameters to the battery cluster-level management unit. The battery cluster-level management unit calculates the current SOC of each battery module based on the parameters.

[0029] In a possible implementation manner, when the battery cluster management unit determines that the difference between the module SOC of any battery module and the average value exceeds a set range, the process of generating the charge / discharge control information of the battery module includes: Calculate the maximum difference DSOCmax between each current SOC and the average value. When it is determined that the maximum difference DSOCmax exceeds the set threshold, determine whether the module SOC of the battery module corresponding to the maximum difference DSOCmax is lower than the average SOC. If so, generate charging control information, otherwise generate discharging control information.

[0030] The balancing control module controls the corresponding contactor to close based on the charge / discharge control information and controls the DC / DC boost module to start charging / discharging the corresponding battery module.

[0031] In a possible implementation manner, the process of charging the battery module of the balancing control module further includes: The balancing control module starts the DC / DC boost module in charging mode, calculates the real-time charging charge based on the integral of the charging current and the charging time, and determines that the balancing is completed when the real-time charging charge reaches the maximum difference DSOCmax. It sends a stop balancing command to control the corresponding contactor to disconnect and the DC / DC boost module to shut down.

[0032] In a possible implementation manner, the process of discharging the battery module of the balancing control module further includes: The balancing control module starts the DC / DC boost module in discharge mode, calculates the real-time charge / discharge charge based on the integral of the discharge current and the discharge time, and determines that the balancing is completed when the real-time discharge charge reaches the maximum difference DSOCmax. It sends a stop balancing command to control the corresponding contactor to disconnect and the DC / DC boost module to shut down.

[0033] In a possible implementation manner, after the battery modules are charged / discharged, the battery cluster-level management unit re-receives the battery information sent from each battery module and updates the current SOC of each battery module.

[0034] In one possible implementation manner, the battery cluster-level management unit updates the current SOC of each battery module and re-judges whether each battery module meets the preset equilibrium state requirement. If the requirement is not met, the battery cluster-level management unit recalculates and judges the current SOC of each battery module and the average value of each current SOC.

[0035] In the specific implementation, during the charging and balancing process, the voltage and current parameters of each battery module are collected by the battery module-level management unit, and the collected voltage and current parameters are sent to the battery cluster-level management unit. The battery cluster-level management unit calculates the voltage and SOC of each battery module in the cluster, determines which module has the largest difference between the SOC and the average SOC, and calculates whether the SOC difference exceeds the set balancing limit. If it exceeds the limit, active balancing is performed, and the charge amount required for the battery module to be balanced is measured, and the module address required to be balanced and the charge amount required to be balanced parameters are sent to the balancing control module. The balancing control module controls the contactor of the corresponding module to close, sends a charging instruction to start the balancing boost DC / DC module, boosts the battery module voltage to the battery cluster voltage, and charges the battery module with a lower state of charge separately. The balancing control module calculates the integral of the charging current and the charging time to determine whether the balanced charge amount is reached, and the cluster-level management unit re-updates the SOC of each battery module to determine whether the balancing is completed. If the balancing is completed, the balancing control module sends a stop balancing instruction to close the contactor and DC / DC boost module corresponding to the balancing module. Complete the balanced charging of a single module.

[0036] During the discharge balancing process, the battery module-level management unit collects the voltage and current parameters of each battery module, and sends the collected parameters to the battery cluster-level management unit. The battery cluster-level management unit calculates the voltage and SOC of each battery module in the cluster, determines which module has the largest difference between SOC and the average SOC, and calculates whether the SOC difference exceeds the set balancing limit. If it exceeds the limit, active balancing is performed, and the charge amount that needs to be balanced for the battery module is measured. The module address that needs to be balanced and the parameters of the amount of electricity that needs to be balanced are sent to the balancing control module. The balancing control module controls the contactor of the corresponding module to close, sends a start-balancing boost DC / DC module to discharge instruction, boosts the voltage of the battery module that needs to be balanced to the battery cluster voltage, and discharges the battery modules with more charge states separately. The balancing control module calculates the integral of the charging current and the charging time to determine whether the balanced charge amount is reached, and the cluster-level management unit 0 re-updates the SOC of each battery module to determine whether the balancing is completed. If the balancing is completed, the balancing control module sends a stop balancing instruction to close the contactor and DC / DC boost module corresponding to the balancing module. The balanced discharge of a single module is completed.

[0037] After completing the balancing of the first module, the battery cluster-level management unit determines the module with the largest difference between the current module SOC and the value, and determines whether the difference between the module SOC and the average SOC is within the balancing limit. If it exceeds the balancing limit, a second round of module charge or discharge balancing is performed. If the difference between the module SOC and the average SOC is within the balancing limit, no balancing is required, which means that the module balancing in the battery cluster is completed and balancing stops.

[0038] Example 2 Embodiment 2 provided by the present invention is an embodiment of an active balancing control method for a battery module provided by the present invention. Figure 2 A flowchart of an active balancing control method for a battery module provided by an embodiment of the present invention, combined with Figure 1 and Figure 2 It can be seen that the embodiment of the control method includes: The current SOC of each battery module and the average value of each current SOC are calculated, and when it is determined that the maximum value of the difference between the current SOC of any battery module and the average value exceeds a set range, the charge / discharge control information of the battery module is generated.

[0039] Each charging / discharging branch is respectively set to connect each battery module with the DC / DC boost module respectively, and the corresponding charging / discharging branch is controlled to be connected based on the charging / discharging control information and the DC / DC boost module is controlled to start charging / discharging the corresponding battery module.

[0040] In a possible implementation manner, the process of generating the charge / discharge control information of the battery module includes: Calculate the maximum difference DSOCmax between each current SOC and the average value. When it is determined that the maximum difference DSOCmax exceeds the set threshold, determine whether the module SOC of the battery module corresponding to the maximum difference DSOCmax is lower than the average SOC. If so, generate charging control information, otherwise generate discharging control information.

[0041] In a possible implementation manner, the process of charging / discharging the battery module further includes: Start the DC / DC boost module in charge / discharge mode, calculate the real-time charge / discharge charge based on the integral of the charge / discharge current and the charge / discharge time, and judge that the balancing is completed when the real-time charge / discharge charge reaches the maximum difference DSOCmax. Send a stop balancing command to control the corresponding contactor to disconnect and the DC / DC boost module to shut down.

[0042] It can be understood that the active balancing control method of a battery module provided by the present invention corresponds to the active balancing circuit of the battery module provided by the aforementioned embodiments. The relevant technical features of the active balancing control method of the battery module can refer to the relevant technical features of the active balancing circuit of the battery module, which will not be repeated here.

[0043] The active balancing circuit and control method of a battery module provided by the embodiment of the present invention only requires a single DC / DC boost module to perform additional charging or discharging on a single battery module to achieve charge consistency of the battery modules in the system battery cluster and complete active balancing. It is not necessary to set a bidirectional DC / DC module for each battery module, which makes the control circuit simpler, and active balancing of the modules can still be performed when the system is in charging or discharging state.

[0044] It should be noted that in the above embodiments, the description of each embodiment has its own emphasis, and for parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0045] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0046] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded computer, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0047] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0048] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0049] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0050] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. An active balancing circuit for a battery module, characterized in that: The circuit includes: a battery cluster level management unit, a balancing control module, a DC / DC boost module and a plurality of battery modules; The battery cluster-level management unit is connected to the balancing control module and each battery module in communication; each battery module is connected to the DC / DC boost module through each charging / discharging branch, each charging / discharging branch includes a contactor, and the balancing module is connected to each contactor and the DC / DC boost module in communication and control; The battery cluster management unit receives battery information sent by each battery module, calculates the current SOC of each battery module and the average value of each current SOC, and generates charge / discharge control information of the battery module and sends it to the balancing control module when it is determined that the maximum value of the difference between the current SOC of any battery module and the average value exceeds a set range; The balancing control module controls the corresponding contactor to close based on the charge / discharge control information and controls the DC / DC boost module to start charging / discharging the corresponding battery module.

2. The circuit according to claim 1, characterized in that The process of generating the charge / discharge control information of the battery module includes: Calculate the maximum difference DSOCmax between each current SOC and the average value. When it is determined that the maximum difference DSOCmax exceeds the set threshold, determine whether the module SOC of the battery module corresponding to the maximum difference DSOCmax is lower than the average SOC. If so, generate charging control information, otherwise generate discharging control information.

3. The circuit according to claim 2, characterized in that The process of charging the battery module of the balancing control module further includes: The balancing control module starts the DC / DC boost module in charging mode, calculates the real-time charging charge based on the integral of the charging current and the charging time, determines that the balancing is completed when the real-time charging charge reaches the maximum difference DSOCmax, and sends a stop balancing instruction to control the corresponding contactor to disconnect and the DC / DC boost module to shut down.

4. The circuit according to claim 2, characterized in that The process of discharging the battery module of the balancing control module further includes: The balancing control module starts the DC / DC boost module in the discharge mode, calculates the real-time charge / discharge charge based on the integral of the discharge current and the discharge time, determines that the balancing is completed when the real-time discharge charge reaches the maximum difference DSOCmax, and sends a stop balancing instruction to control the corresponding contactor to disconnect and the DC / DC boost module to shut down.

5. The circuit according to claim 1, characterized in that The battery module comprises: a battery module level management unit; The battery module-level management unit collects voltage and current parameters of the battery module, and sends the collected parameters to the battery cluster-level management unit. The battery cluster-level management unit calculates the current SOC of each battery module based on the parameters.

6. The circuit according to claim 1, characterized in that After the charging / discharging of the battery module is completed, the battery cluster-level management unit re-receives the battery information sent by each battery module and updates the current SOC of each battery module.

7. The circuit according to claim 6, characterized in that The battery cluster-level management unit updates the current SOC of each battery module and re-judges whether each battery module meets the preset equilibrium state requirement. If the requirement is not met, the battery cluster-level management unit recalculates and judges the current SOC of each battery module and the average value of each current SOC.

8. An active balancing control method for a battery module, characterized in that: The control method comprises: Calculating the current SOC of each battery module and the average value of each current SOC, and generating charge / discharge control information of the battery module when it is determined that the maximum value of the difference between the current SOC of any battery module and the average value exceeds a set range; Each charging / discharging branch is respectively set to connect each battery module with the DC / DC boost module respectively, and the corresponding charging / discharging branch is controlled to be connected based on the charging / discharging control information and the DC / DC boost module is controlled to start charging / discharging the corresponding battery module.

9. The control method according to claim 8, characterized in that: The process of generating the charge / discharge control information of the battery module includes: Calculate the maximum difference DSOCmax between each current SOC and the average value. When it is determined that the maximum difference DSOCmax exceeds the set threshold, determine whether the module SOC of the battery module corresponding to the maximum difference DSOCmax is lower than the average SOC. If so, generate charging control information, otherwise generate discharging control information.

10. The control method according to claim 9, characterized in that: The process of charging / discharging the battery module further includes: The DC / DC boost module is started in the charge / discharge mode, and the real-time charge / discharge charge is calculated based on the integral of the charge / discharge current and the charge / discharge time. When the real-time charge / discharge charge reaches the maximum difference DSOCmax, it is determined that the balancing is completed, and a stop balancing instruction is sent to control the corresponding contactor to disconnect and the DC / DC boost module to shut down.

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