Battery system, control method of battery system, device, and storage medium

Abstract

This application discloses a battery system, a control method for the battery system, an apparatus, and a storage medium. The battery system includes a main control module and multiple battery cells connected in parallel. A battery cluster includes multiple cells connected in series, with a first end of the battery cluster connected to a first common node. A first output terminal of a DC / DC conversion module is connected to a second end of the battery cluster, and a second output terminal is connected to a second common node. The main control module is used to determine a portion of the battery clusters based on their state of charge (SOC) values ​​during charging or discharging, and to control the current of a portion of the DC / DC conversion modules to reduce the SOC differences between the battery clusters. The main control module is also used to short-circuit a portion of the DC / DC conversion modules during SOC balancing. According to an embodiment of this application, current control is applied to a portion of the battery clusters based on their SOC values ​​to balance the SOC values. When SOC balance is achieved, the DC / DC conversion modules can be stopped to save power consumption and improve system efficiency.

Description

Technical Field

[0001] This application belongs to the field of battery management technology, and in particular relates to a battery system, a control method for the battery system, a device and a storage medium. Background Technology

[0002] In existing battery system solutions, multiple battery clusters are usually connected in direct parallel and connected to the output DC / AC (Direct Current / Alternating Current) converter, PCS (Power Conversion System), or load.

[0003] Due to differences in cell capacity, internal resistance, and other factors within each battery cluster, the SOC (State of Charge), i.e., the remaining charge, varies among different battery clusters when connected in parallel. When the SOC of a particular battery cluster differs significantly from that of other battery clusters, that cluster will prematurely reach its discharge or charge cutoff state, thus affecting the charging and discharging operation of multiple battery clusters.

[0004] To avoid significant differences in the State of Charge (SOC) of one battery cluster compared to others, a DC / DC converter is typically connected in series with each battery cluster to balance their SOC and prevent large discrepancies. However, the DC / DC converter incurs power transfer losses during operation, resulting in a substantial reduction in the operating efficiency of the battery system. Summary of the Invention

[0005] This application provides a battery system, a control method for the battery system, a device, and a storage medium, which can solve the technical problem of large power loss when setting up a DC / DC converter to equalize the SOC.

[0006] In a first aspect, embodiments of this application provide a battery system, which includes a main control module and multiple battery cells connected in parallel. Each battery cell includes:

[0007] A battery cluster, comprising multiple batteries connected in series, with the first end of the battery cluster connected to a first common node;

[0008] The DC / DC converter module has a first output terminal connected to the second terminal of the battery pack, and a second output terminal connected to the second common node; the first input terminal of the DC / DC converter module is connected to the first terminal of the battery pack, and the second input terminal of the DC / DC converter module is connected to the second terminal of the battery pack.

[0009] The main control module is used to determine a portion of the battery clusters based on the state of charge value of each battery cluster during charging or discharging, and control the corresponding DC / DC conversion modules of the battery clusters to control the charging current or discharging current, so as to reduce the difference in state of charge value between the battery clusters during charging or discharging.

[0010] The main control module is also used to short-circuit the first and second output terminals of some DC / DC conversion modules when the difference in state of charge between the various battery clusters meets the balancing condition.

[0011] By configuring a DC / DC conversion module, the state of charge (SOC) value of each battery cluster in the battery system can be acquired during charging or discharging. Based on the SOC value, a subset of battery clusters can be identified from multiple clusters. The main control module can send control commands to the DC / DC conversion module corresponding to this subset of battery clusters to control the charging or discharging current of its corresponding branch. By adjusting the charging or discharging current of the branch containing this subset of battery clusters, the SOC value of this subset can gradually approach that of other battery clusters during charging or discharging, thus reducing the SOC value difference between the various battery clusters. Furthermore, when the SOC value difference between the various battery clusters meets the equalization condition, the main control module can short-circuit the two output terminals of the DC / DC conversion module that is currently in operation, causing this subset of DC / DC conversion modules to stop operating. This reduces the power loss of the DC / DC conversion module, saves battery system power consumption, and improves the output efficiency of the battery system.

[0012] According to some embodiments of this application, the battery cell further includes:

[0013] The bypass switch has its first terminal connected to the first output terminal of the DC / DC converter module, its second terminal connected to the second output terminal of the DC / DC converter module, and its control terminal connected to the bypass control terminal of the DC / DC converter module.

[0014] The main control module is used to send bypass commands or load operation commands to the DC / DC conversion module, so that the DC / DC conversion module controls the bypass switch to turn on according to the bypass command or controls the bypass switch to turn off according to the load operation command.

[0015] By setting a bypass switch, the output of the DC / DC converter module can be short-circuited when the bypass switch is turned on, so that the battery cluster can be directly connected in parallel with other battery cells, thereby reducing the operating power consumption of the DC / DC converter module.

[0016] According to some embodiments of this application, the main control module is also used to send a voltage adjustment command to the DC / DC conversion module based on the battery cluster voltage of each battery cell, so as to keep the total output voltage of each branch where the battery cell is located balanced.

[0017] By controlling the bypass switch to turn on and off through the DC / DC conversion module, the DC / DC conversion module can control the bypass switch to turn on or off when it receives a bypass command or load operation command sent by the main control module. This enables the switching between directly connecting the battery cluster in parallel with other battery units and connecting the battery cluster in series with the DC / DC conversion module before connecting it in parallel with other battery units.

[0018] According to some embodiments of this application, the battery cell further includes:

[0019] Branch switch, which is connected in series with the battery pack, is in the open state before charging or discharging;

[0020] The main control module is also used to send voltage adjustment commands to each DC / DC conversion module before charging or discharging, and to control the branch switches of each battery cell to be turned on when the total output voltage of each branch of the battery cell is kept balanced.

[0021] The main control module can acquire the voltage of each battery cluster during battery system operation. When there is a significant difference between the voltages of different battery clusters, the DC / DC conversion module needs to be activated to compensate for the battery cluster voltages using its output voltage. This ensures that the total output voltage across all battery cells remains balanced, preventing circulating current effects between them. However, since the DC / DC conversion module incurs additional power losses during voltage adjustment, the main control module can also short-circuit the two output terminals of the corresponding DC / DC conversion module when the voltage of a particular battery cluster is consistent with or very close to that of the other battery clusters. This allows the battery cluster to be directly connected in parallel with other battery cells. In this case, the DC / DC conversion module does not provide an output voltage, reducing its operating losses.

[0022] Secondly, embodiments of this application provide a control method for a battery system, applied to the main control module of the aforementioned battery system, comprising:

[0023] During battery system charging or discharging, the state of charge (SOC) value of the battery clusters in each battery cell is obtained;

[0024] Determine a subset of battery clusters based on the state of charge (SOC) values ​​of each cluster.

[0025] The control module controls the charging or discharging current of the corresponding DC / DC conversion module of the battery cluster to reduce the difference in state of charge between the battery clusters during charging or discharging.

[0026] When the state of charge of each battery cluster reaches equilibrium, the first and second output terminals of some DC / DC conversion modules are short-circuited.

[0027] By setting up a main control module, the state of charge (SOC) value of each battery cluster can be detected. Based on the SOC values ​​of each cluster, a subset of battery clusters can be identified. By controlling the corresponding DC / DC converter module for this subset, the charging or discharging current of the subset can be controlled to adjust its charging or discharging rate. By adjusting a subset of battery clusters, the differences in SOC values ​​between the clusters can be reduced, allowing the SOC values ​​of the clusters to gradually reach equilibrium during charging or discharging. When the main control module determines that the SOC values ​​of the battery clusters have reached equilibrium, the output of the DC / DC converter module in that subset can be short-circuited to disconnect it from operation. This reduces the power loss of the DC / DC converter module, saves battery system power consumption, and improves the output efficiency of the battery system.

[0028] According to some embodiments of this application, determining a portion of the battery clusters based on the state of charge (SOC) values ​​of each battery cluster includes:

[0029] A preset number of battery clusters are selected from high to low based on their state of charge values.

[0030] The control module for a portion of the battery clusters performs current control on the charging or discharging current to reduce the difference in state of charge (SOC) values ​​between the individual battery clusters during charging or discharging.

[0031] When the battery system is charging, the DC / DC conversion module corresponding to a preset number of battery clusters is controlled to disconnect the bypass switch and reduce the charging current of the branch.

[0032] When the battery system is discharging, the DC / DC conversion module corresponding to a preset number of battery clusters disconnects the bypass switch and increases the discharge current of the corresponding branch.

[0033] After identifying the battery clusters with higher charge levels from multiple battery clusters, the main control module can reduce the charging current of these clusters during charging, thus slowing down their charging speed relative to the lower charge clusters and narrowing the charge difference between the battery clusters. Conversely, the main control module can increase the discharging current of these clusters during discharging, thereby increasing their discharging speed relative to the lower charge clusters and further narrowing the charge difference between the battery clusters.

[0034] According to some embodiments of this application, after short-circuiting the first and second output terminals of some DC / DC conversion modules when the state of charge values ​​of each battery cluster reach equilibrium, the method further includes:

[0035] Battery clusters whose state of charge values ​​meet the cutoff condition are identified as cutoff battery clusters;

[0036] Reduce the total operating power based on the current operating power of the cutoff battery cluster;

[0037] Reduce the current of the cut-off battery cluster until it reaches a safe current range, then disconnect the branch switch corresponding to the battery cell containing the cut-off battery cluster.

[0038] When a battery cluster meets the cutoff condition, the main control module can control the cutoff battery cluster to be safely disconnected, and reduce the total operating power to allow other battery clusters to continue charging or discharging, so that each battery cluster can reach a fully charged or fully discharged state.

[0039] According to some embodiments of this application, before obtaining the state-of-charge value of the battery clusters in each battery cell during charging or discharging of the battery system, the method further includes:

[0040] Before charging or discharging the battery system, obtain the battery cluster voltage of each battery cell.

[0041] The compensation voltage for each DC / DC conversion module is determined based on the battery cluster voltage of each battery cluster.

[0042] Control the output of each DC / DC conversion module to provide the corresponding compensation voltage;

[0043] When the total output voltage of each battery cell's branch reaches equilibrium, the branch switch of each battery cell is turned on.

[0044] By setting up a main control module and connecting each battery cluster in series with a DC / DC conversion module, the main control module can detect and acquire the voltage of each battery cluster. Based on the voltage of each battery cluster, the main control module can determine the voltage difference between the individual battery clusters and calculate the compensation voltage for the corresponding DC / DC conversion module. The main control module sends voltage adjustment commands containing the compensation voltage to each DC / DC conversion module, causing each module to output the corresponding compensation voltage. The total output voltage of each battery cell is the sum of the battery cluster voltage and the compensation voltage. When there are differences in the voltage of each battery cluster, adjusting the compensation voltage can compensate for these differences, ensuring a balanced total output voltage across all battery cells. When the total output voltage of each battery cell is balanced, the main control unit can control the branch switch to turn on, initiating the charging or discharging process. Compensating the voltage of each battery cluster before charging or discharging reduces the difference in total output voltage between battery cells, decreases internal circulating currents between battery cells, reduces the risk of loops, and improves the output efficiency of the battery system.

[0045] According to some embodiments of this application, before determining the compensation voltage corresponding to each DC / DC conversion module based on the battery cluster voltage of each battery cluster, the method further includes:

[0046] The maximum and minimum battery cluster voltage values ​​are determined from the battery cluster voltages of each battery cluster.

[0047] When the difference between the maximum and minimum battery cluster voltage values ​​is greater than a preset voltage threshold, the following steps are executed: determine the compensation voltage corresponding to each DC / DC conversion module based on the battery cluster voltage of each battery cluster.

[0048] When the difference between the maximum and minimum battery cluster voltage values ​​is less than or equal to a preset voltage threshold, control the bypass switches of each DC / DC conversion module to be turned on.

[0049] When the bypass switches of each battery cell are all turned on, the branch switches of each battery cell are turned on.

[0050] Before the battery system is powered on, the main control module can calculate the difference between the maximum and minimum battery cluster voltage values ​​in each battery cluster, and determine whether to control each DC / DC conversion module to operate based on the difference.

[0051] According to some embodiments of this application, the compensation voltage corresponding to each DC / DC conversion module is determined based on the battery cluster voltage of each battery cluster, including:

[0052] Determine the maximum battery cluster voltage value and the battery cell corresponding to the maximum battery cluster voltage value from the battery cluster voltages of each battery cluster;

[0053] The minimum compensation voltage of the DC / DC conversion module is used as the compensation voltage of the DC / DC conversion module in the battery cell corresponding to the maximum battery cluster voltage value.

[0054] The compensation voltage of the DC / DC conversion module in each battery cell is calculated based on the difference between the battery cluster voltage of each battery cell other than the battery cell corresponding to the maximum battery cluster voltage value and the maximum battery cluster voltage value.

[0055] The main control module can calculate the compensation voltage corresponding to the voltage of other battery clusters based on the minimum compensation voltage corresponding to the maximum battery cluster voltage value, and control the DC / DC conversion module to output the corresponding compensation voltage.

[0056] Thirdly, embodiments of this application provide a control device for a battery system, the control device for the battery system including: a processor and a memory storing computer program instructions;

[0057] The processor implements the above-described control method for the battery system when executing computer program instructions.

[0058] Fourthly, embodiments of this application provide a computer storage medium storing computer program instructions, which, when executed by a processor, implement the above-described control method for the battery system.

[0059] Compared with existing technologies, the battery system, battery system control method, device, and storage medium provided in this application, by setting a main control module and multiple DC / DC conversion modules, can acquire the state of charge (SOC) value of each battery cluster in each battery cell during battery system charging or discharging, and determine a subset of battery clusters from multiple battery clusters based on the magnitude of the SOC value. The main control module can control the charging or discharging current of the DC / DC conversion module corresponding to the subset of battery clusters by sending control commands. By adjusting the charging or discharging current of the branch containing the subset of battery clusters, the SOC value of the subset of battery clusters can gradually approach the SOC value of other battery clusters during charging or discharging, thus reducing the difference in SOC value between battery clusters. Furthermore, when the state of charge difference between the various battery clusters meets the balancing condition, the main control module can short-circuit the two output terminals of the DC / DC conversion module that is in operation, thereby stopping the operation of that DC / DC conversion module, reducing the power loss of the DC / DC conversion module, saving battery system power consumption, and improving the output efficiency of the battery system. Attached Figure Description

[0060] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0061] Figure 1 This is a schematic diagram of the circuit structure of a battery system provided in an embodiment of this application;

[0062] Figure 2 This is a schematic diagram of the circuit structure of a battery system provided in another embodiment of this application;

[0063] Figure 3 This is a schematic diagram of the circuit structure of a battery system provided in another embodiment of this application;

[0064] Figure 4 This is a schematic flowchart of a control method for a battery system provided in an embodiment of this application;

[0065] Figure 5 This is a schematic flowchart of a control method for a battery system provided in another embodiment of this application;

[0066] Figure 6 This is a schematic flowchart of a control method for a battery system provided in another embodiment of this application;

[0067] Figure 7 This is a schematic flowchart of a control method for a battery system provided in another embodiment of this application;

[0068] Figure 8 This is a flowchart illustrating the pre-power-on stage and the charge / discharge initiation stage in one embodiment of this application;

[0069] Figure 9 This is a flowchart illustrating the platform area stage in one embodiment of this application;

[0070] Figure 10 This is a schematic flowchart of the charging and discharging end region stage in one embodiment of this application;

[0071] Figure 11 This is a schematic diagram of the structure of the control device of the battery system provided in one embodiment of this application.

[0072] In the attached image:

[0073] 10. Battery unit; 11. Battery cluster; 12. DC / DC conversion module; 13. Bypass switch; 14. Detection module; 15. Branch switch; 20. Main control module; N1. First common node; N2. Second common node. Detailed Implementation

[0074] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples of this application.

[0075] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0076] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The embodiments will now be described in detail with reference to the accompanying drawings.

[0077] In existing battery system solutions, multiple battery clusters are usually connected in direct parallel and connected to the output DC / AC converter, PCS, or load.

[0078] Due to differences in cell capacity, internal resistance, and other factors within each battery cluster, the State of Charge (SOC) of different battery clusters varies when connected in parallel. When the SOC of a particular battery cluster differs significantly from that of other battery clusters, that cluster will reach its discharge or charge cutoff state prematurely, thus affecting the charging and discharging operation of multiple battery clusters.

[0079] To avoid significant differences in the State of Charge (SOC) of one battery cluster compared to others, a DC / DC converter is typically connected in series with each battery cluster to balance their SOC and prevent large discrepancies. However, the DC / DC converter incurs power transfer losses during operation, resulting in a substantial reduction in the battery system's operating efficiency.

[0080] To address the aforementioned technical problems, embodiments of this application provide a battery system, a control method for the battery system, an apparatus, and a storage medium. The battery system provided in this application embodiment will be described below.

[0081] Figure 1 A schematic diagram of a battery system provided in one embodiment of this application is shown. The battery system includes a main control module 20 and multiple battery cells 10 connected in parallel. Each battery cell 10 includes a battery cluster 11 and a DC / DC conversion module 12.

[0082] Battery cluster 11 includes multiple batteries connected in series. A first end of battery cluster 11 is connected to a first common node N1. A first output of DC / DC converter module 12 is connected to a second end of battery cluster 11, and a second output of DC / DC converter module 12 is connected to a second common node N2. A first input of DC / DC converter module 12 is connected to a first end of battery cluster 11, and a second input of DC / DC converter module 12 is connected to a second end of battery cluster 11.

[0083] The main control module 20 can acquire the state of charge (SOC) value of each battery cluster 11 during battery system charging or discharging, and determine a subset of battery clusters 11 from all battery clusters 11 based on their SOC values. The main control module can send control commands to the DC / DC conversion modules 12 corresponding to these subset of battery clusters 11 to control the charging or discharging current of their respective branches. When there are differences in the SOC values ​​of the various battery clusters 11 during charging or discharging, the main control module 20 can control the current of some DC / DC conversion modules 12 to change the charging or discharging speed of some battery clusters 11, thereby reducing the differences in SOC values ​​between the various battery clusters 11. In other words, it aims to make the SOC values ​​of the various battery clusters 11 more balanced.

[0084] When the main control module 20 performs current control through the control section DC / DC conversion module 12, it can also determine the difference in state of charge (SOC) values ​​between each battery cluster 11 based on the SOC values ​​of each battery cluster 11. When the difference in SOC values ​​between each battery cluster 11 meets the balancing condition, the main control module 20 can short-circuit the first and second output terminals of this part of the DC / DC conversion module 12, thereby stopping the current control of this part of the DC / DC conversion module 12, thus reducing the operating time of the DC / DC conversion module 12 during charging or discharging and reducing the power loss generated during operation. The balancing condition can be that the SOC value of each battery cluster 11 reaches the average value of the SOC values ​​of all battery clusters 11, or the difference between the largest and smallest SOC values ​​is within a preset range.

[0085] In this embodiment, the main control module 20 can acquire the state of charge (SOC) values ​​of battery clusters 11 in each battery cell 10 during battery system charging or discharging, and determine a subset of battery clusters 11 from multiple battery clusters 11 based on the magnitude of the SOC values. The main control module 20 can send control commands to the DC / DC conversion module 12 corresponding to this subset of battery clusters 11, thereby controlling the charging or discharging current of the branch in which it resides. By adjusting the charging or discharging current of the branch containing a subset of battery clusters 11, the SOC value of this subset of battery clusters 11 can gradually approach the SOC values ​​of other battery clusters 11 during charging or discharging, thus reducing the difference in SOC values ​​between the various battery clusters 11. Furthermore, when the difference in state of charge between each battery cluster 11 meets the balancing condition, the main control module 20 can short-circuit the two output terminals of the DC / DC conversion module 12 that is in operation, so as to stop the operation of the DC / DC conversion module 12, thereby reducing the power loss of the DC / DC conversion module 12, saving battery system power consumption, and improving the output efficiency of the battery system.

[0086] According to some embodiments of this application, please refer to Figure 2 The battery unit 10 may also include a bypass switch 13. The first terminal of the bypass switch 13 is connected to the first output terminal of the DC / DC conversion module 12, the second terminal of the bypass switch 13 is connected to the second output terminal of the DC / DC conversion module 12, and the control terminal of the bypass switch 13 is connected to the bypass control terminal of the DC / DC conversion module 12.

[0087] The main control module 20 can send bypass commands or load operation commands to the DC / DC conversion module 12. When the DC / DC conversion module 12 receives a bypass command, it can control the bypass switch 13 to turn on, short-circuiting the first and second output terminals of the DC / DC conversion module 12. At this time, the DC / DC conversion module 12 stops operating, and the two ends of the battery cluster 11 are directly connected in parallel with other battery units 10. When the DC / DC conversion module 12 receives a load operation command, it can control the bypass switch 13 to turn off. At this time, the output terminal of the DC / DC conversion module 12 is connected in series with the battery cluster 11, and the total output voltage of the battery unit 10 is the sum of the battery cluster voltage and the output voltage of the DC / DC conversion module 12.

[0088] By controlling the bypass switch 13 to turn on and off through the DC / DC conversion module 12, the DC / DC conversion module 12 can control the bypass switch 13 to turn on or off when it receives a bypass command or load operation command sent by the main control module 20. This enables the switching between directly connecting the battery cluster 11 in parallel with other battery units 10 and connecting the battery cluster 11 in series with the DC / DC conversion module 12 and then in parallel with other battery units 10.

[0089] According to some embodiments of this application, the main control module 20 can send a voltage adjustment command to the DC / DC conversion module 12 corresponding to the battery cluster 11 in each battery cell 10 based on the battery cluster voltage of the battery cluster 11 in each battery cell 10, so as to keep the total output voltage of each branch where the battery cell 10 is located balanced.

[0090] The two input terminals of the DC / DC converter module 12 are respectively connected to the two ends of the battery cluster 11. That is, the battery cluster 11 can provide input voltage to the input terminals of the DC / DC converter module 12. After adjusting the input voltage, the DC / DC converter module 12 can output a corresponding output voltage to adjust the total output voltage of the branch where the battery unit 10 is located.

[0091] For any given battery cell 10, the total output voltage of its branch is the sum of the battery cluster voltage and the output voltage of the DC / DC converter module 12. Since each battery cell 10 is connected to the first common node N1 and the second common node N2, the multiple battery cells 10 are connected in parallel. To reduce the circulating current between the battery cells 10 when they are connected in parallel, the total output voltage of each battery cell 10 needs to be kept close or consistent. When there are differences in the battery cluster voltages of the various battery clusters 11, the total output voltage of the battery cell 10 can be adjusted by adjusting the output voltage of the DC / DC converter module 12. For example, when the voltage of the battery cluster 11 in a certain battery cell 10 is lower than that of other battery clusters, the main control module 20 can determine the voltage difference between the voltage of the battery cluster and that of other battery clusters, and send a voltage adjustment command to the DC / DC conversion module 12 of the battery cell 10 so that the output voltage of the DC / DC conversion module 12 is increased. This allows the battery cell 10 to maintain a consistent or close total output voltage with that of other battery cells 10 when the battery cluster voltage is low by increasing the output voltage of the DC / DC conversion module 12.

[0092] Before the battery system is powered on, the main control module 20 can acquire the battery cluster voltage of each battery cluster 11. If there is a significant difference between the voltages of the battery clusters, the DC / DC conversion module 12 needs to be activated to compensate for the battery cluster voltages through its output voltage. This ensures that the total output voltage among the battery cells 10 remains balanced, preventing circulating current effects between the battery cells 10. However, since the DC / DC conversion module 12 incurs additional power losses during voltage adjustment, the main control module 20 can also short-circuit the two output terminals of the DC / DC conversion module 12 corresponding to a battery cluster 11 when the voltage of a certain battery cluster is consistent with or close to the voltages of other battery clusters. This allows the battery cluster 11 to be directly connected in parallel with other battery cells 10. In this case, the DC / DC conversion module 12 does not provide an output voltage, reducing its operating losses.

[0093] When determining whether the battery cluster voltage in a certain battery cell 10 differs from the battery cluster voltages of other battery clusters 11, the main control module 20 can compare it with the battery cluster 11 with the highest battery cluster voltage among multiple battery cells 10, or it can compare it with the average value of the voltages of each battery cluster. For example, the main control module 20 can acquire the battery cluster voltages of each battery cluster 11 and determine the highest battery cluster voltage. For other battery cells 10, based on the voltage difference between the battery cluster voltage in that battery cell 10 and the highest battery cluster voltage, a voltage adjustment command can be sent to the DC / DC conversion module 12 in that battery cell 10. This allows the DC / DC conversion module 12 to compensate for the battery difference through its output voltage, ensuring that the total output voltage of that battery cell 10 is balanced with the total output voltage of the battery cell 10 corresponding to the highest battery cluster voltage. Furthermore, when the main control module 20 calculates the voltage difference between the battery cluster voltage of each battery cluster 11 and the maximum battery cluster voltage, if the voltage difference is small, the main control module 20 can also short-circuit the first and second output terminals of the DC / DC conversion module 12 in the battery unit 10. At this time, the total output voltage of the battery unit 10 is the battery cluster voltage of the battery cluster 11. Since the voltage difference between the battery cluster voltage of the battery cluster 11 and the maximum battery cluster voltage is small, the circulating current generated between the battery unit 10 and the battery unit 10 corresponding to the maximum battery cluster 11 is small and will not be affected by excessive circulating current.

[0094] According to some embodiments of this application, the two input terminals of the DC / DC conversion module 12 can be connected to the two ends of the battery cluster 11 within the same battery unit 10, respectively, so that all the batteries in the battery cluster 11 can be used as the power source of the DC / DC conversion module 12. The two input terminals of the DC / DC conversion module 12 can also be connected to a battery string formed by connecting some of the batteries in the battery cluster 11 in series, so that part of the batteries in the battery cluster 11 can be used as the power source. Furthermore, the power source of the DC / DC conversion module 12 can also be the battery cluster 11 in other battery units 10, additional independent batteries, supercapacitors, and DC buses, etc.

[0095] According to some embodiments of this application, the battery unit 10 may further include a branch switch 15, which is connected in series with the battery cluster 11. The branch switch 15 is in an open state before the battery system is powered on for charging or discharging.

[0096] Before the battery system is powered on for charging or discharging, the main control module 20 determines the compensation voltage of each DC / DC conversion module 12 based on the battery cluster voltage of each battery cluster 11, and sends a voltage adjustment command containing the compensation voltage to each DC / DC conversion module 12. When the compensation voltage output by each DC / DC conversion module 12 keeps the total output voltage of the branch where each battery cell 10 is located balanced, the main control module 20 can control the branch switch 15 in each battery cell 10 to be turned on, so that each battery cell 10 can start charging or discharging.

[0097] By setting branch switch 15, branch switch 15 can be turned off before the battery system is powered on. After the main control module 20 controls the DC / DC conversion module 12 to output compensation voltage so that the total output voltage of the branch where the battery unit 10 is located is kept balanced, the main control module 20 can control the branch switch 15 to be turned on so that the battery unit 10 can start charging or discharging.

[0098] According to some embodiments of this application, please refer to Figure 3 The battery unit 10 may further include a detection module 14. The multiple detection terminals of the detection module 14 are respectively connected to the multiple batteries of the battery cluster 11, and the signal terminal of the detection module 14 is communicatively connected to the main control module 20.

[0099] The detection module 14 can detect the battery cluster voltage of the battery cluster 11 and send the detected battery cluster voltage to the main control module 20.

[0100] It is understood that the battery cluster 11 is composed of multiple batteries connected in series, and the detection module 14 can also be connected to multiple detection sub-units. Each detection sub-unit corresponds one-to-one with a battery in the battery cluster 11, and each detection sub-unit can detect the battery voltage of its corresponding battery. The detection module 14 can calculate the battery cluster voltage of the battery cluster 11 based on the battery voltage detected by each detection sub-unit.

[0101] By setting up the detection module 14, the battery cluster voltage of the battery cluster 11 can be detected, so that the main control module 20 can control the corresponding DC / DC conversion module 12 according to the battery cluster voltage of each battery cluster 11, thereby achieving a balance of the total output voltage of each battery unit 10.

[0102] According to some embodiments of this application, the detection module 14 can also detect the current of the battery cluster 11 and the temperature information of each battery in the battery cluster 11, and send them to the main control module 20.

[0103] The detection module 14 can also be connected to multiple detection sub-units, each corresponding one-to-one with a battery in the battery cluster 11. Each detection sub-unit can detect the battery temperature information of its corresponding battery. The detection module 14 can also detect the current of the battery cluster 11. After receiving the battery temperature information from each detection sub-unit, the detection module 14 can send the temperature information of each battery and the current of the battery cluster 11 to the main control module 20.

[0104] Each battery cluster 11 in the battery system typically has multiple acquisition systems (CSCs, or Cell Supervisory Controllers). Each CSC can detect the temperature and voltage information of the corresponding battery in the battery cluster 11. Each battery cluster 11 also has a cluster-level battery management system (SBMU, or Slave Battery Management Unit). The SBMU can communicate with each CSC to receive the battery information detected by the CSCs. It can be understood that the SBMU can function as a detection module 14, and the CSCs can function as detection sub-units.

[0105] By setting up the detection module 14, the current of the battery cluster 11 and the temperature of each battery in the battery cluster 11 can be detected, so that the main control module 20 can obtain the status information of each battery in the battery cluster 11 and the current information of the battery cluster 11, and control the corresponding DC / DC conversion module 12 according to the above information to achieve the balance of the total output voltage of each battery unit 10 and the balance of the state of charge value of each battery cluster 11.

[0106] Figure 4A flowchart illustrating a control method for a battery system according to an embodiment of this application is shown. The control method is applied to the main control module of the battery system in the above embodiment, and includes:

[0107] S110: When the battery system is charging or discharging, the state of charge value of the battery cluster in each battery cell is obtained.

[0108] S120, determine a portion of the battery clusters based on the state of charge value of each battery cluster;

[0109] S130 controls the DC / DC conversion modules corresponding to some battery clusters to control the charging current or discharging current, so as to reduce the difference in state of charge value between each battery cluster during the charging or discharging process.

[0110] S140, when the state of charge values ​​of each battery cluster reach equilibrium, short-circuit the first and second output terminals of some DC / DC conversion modules.

[0111] In the S110, the battery system includes a main control module and multiple battery cells connected in parallel. The output of each battery cell can be connected to a DC / AC converter, a PCS, or a load. Each battery cell includes a battery cluster and a DC / DC conversion module. The input of the DC / DC conversion module is connected in parallel with the battery cluster, and its output is connected in series with the battery cluster. That is, the battery cluster provides an input voltage to the DC / DC conversion module, and the DC / DC conversion module adjusts the input voltage to generate a corresponding output voltage. The main control module can acquire the state-of-charge (SOC) value of the battery cluster in each battery cell when the battery system is charging or discharging.

[0112] In S120, after acquiring the state of charge (SOC) values ​​of each battery cluster, the main control module can identify a subset of battery clusters from the multiple battery clusters. This subset of battery clusters can be a subset of battery clusters with higher SOC values, a subset of battery clusters with lower SOC values, or a subset of battery clusters whose SOC values ​​differ significantly from the average SOC values.

[0113] In S130, after identifying a subset of battery clusters from multiple battery clusters, the main control module can determine its corresponding DC / DC conversion module and control the charging or discharging current of that module. During charging or discharging, by controlling the charging or discharging current of this subset of battery clusters, the charging or discharging rate of that subset can be adjusted, causing its state of charge (SOC) value to gradually approach that of other battery clusters, thereby reducing the SOC difference between the various battery clusters. It should be noted that the DC / DC conversion modules for other battery clusters are not actively used.

[0114] In S140, when the main control module controls the current of the DC / DC conversion module, it can also obtain the state of charge value of each battery cluster in real time. When the state of charge value of each battery cluster reaches equilibrium, it short-circuit the first and second output terminals of the DC / DC conversion module that is currently running, so that the DC / DC conversion module is switched off from the running state.

[0115] Understandably, when the cell consistency of each battery cluster is high, the difference in the state of charge (SOC) between the various battery clusters is small when the main control module switches on the DC / DC conversion module. By adjusting the loop current of some battery clusters, the difference in SOC between the various battery clusters can be gradually reduced until the SOC of the various battery clusters reaches equilibrium. At this point, the main control module can control the DC / DC conversion module that has switched on to operate to switch off from the operating state, allowing the various battery clusters to be directly connected in parallel. If the cell consistency of each battery cluster is poor, the difference in SOC between the various battery clusters will be large when the main control module controls the DC / DC conversion module to operate. During the switching-off process, although the difference in SOC between the various battery clusters can be gradually reduced, the state of SOC of the various battery clusters still cannot reach equilibrium. In this case, the main control module can short-circuit the DC / DC conversion module that has switched on to operate when other switching-off conditions are met, thereby switching off the DC / DC conversion module. For example, the cut-out condition could be that the state of charge (SOC) of the battery cluster enters the end range of charging and discharging, such as when the SOC reaches 80% or more during charging or 20% or less during discharging. The cut-out condition could also be a preset adjustment period; that is, after the main control module controls the DC / DC conversion module to switch in and runs the preset adjustment period, it can control the DC / DC conversion module to switch out.

[0116] In this embodiment, by setting a main control module, the state of charge (SOC) value of each battery cluster can be detected. Based on the SOC values ​​of each battery cluster, a subset of battery clusters can be identified. By controlling the corresponding DC / DC conversion module of this subset of battery clusters, the charging or discharging current of this subset can be controlled to adjust the charging or discharging speed of this subset. By adjusting a subset of battery clusters, the difference in SOC values ​​between the various battery clusters can be reduced, thereby gradually achieving SOC balance during charging or discharging. When the main control module determines that the SOC values ​​of the various battery clusters have reached balance, the output terminal of the DC / DC conversion module that is currently in operation can be short-circuited, causing the DC / DC conversion module to be switched off from operation. This reduces the power loss of the DC / DC conversion module, saves battery system power consumption, and improves the output efficiency of the battery system.

[0117] According to some embodiments of this application, please refer to Figure 5 The above-mentioned S120 may include:

[0118] S210, Select a preset number of battery clusters from high to low according to the state of charge value of each battery cluster;

[0119] The above S130 may include:

[0120] S220, when the battery system is charging, controls the DC / DC conversion module corresponding to a preset number of battery clusters to disconnect the bypass switch and reduce the charging current of the branch.

[0121] S230, when the battery system is discharging, controls the DC / DC conversion module corresponding to a preset number of battery clusters to disconnect the bypass switch and increase the discharge current of the branch.

[0122] In S210, after determining the state of charge (SOC) value of each battery cluster, the main control module can select a preset number of battery clusters in descending order of SOC value. The main control module can adjust the charging or discharging speed of the preset number of battery clusters to gradually bring their SOC values ​​closer to those of the other battery clusters.

[0123] In S220, if the current battery system is in a charging state, the main control module can, after determining the DC / DC conversion modules corresponding to the preset number of battery clusters, control the bypass switches of the DC / DC conversion modules to switch on and reduce the charging current of the branch where the preset number of battery clusters are located by adjusting the output voltage of the DC / DC conversion modules.

[0124] During charging, after selecting battery clusters with higher state of charge (SOC) values ​​from multiple clusters, reducing the charging current of these clusters slows down their charging rate, thus reducing the rate of increase in SOC value. Other battery clusters with lower SOC values ​​can then continue charging at a relatively higher current, gradually bringing their SOC values ​​closer to those of the clusters limiting the charging current. In other words, by slowing down the charging rate of the clusters with higher SOC values, the difference in SOC value between the clusters with lower SOC values ​​and those with higher SOC values ​​can be reduced.

[0125] Similarly, during the discharge process, after selecting a portion of battery clusters with higher state of charge (SOC) values ​​from multiple battery clusters, increasing the discharge current of these battery clusters can improve the discharge rate, thereby rapidly reducing the charge of the battery clusters with higher SOC values ​​and narrowing the SOC value difference between them and the battery clusters with lower SOC values.

[0126] In this embodiment, after identifying the battery clusters with higher charge levels from multiple battery clusters, the main control module can reduce the charging current of these battery clusters during charging, thereby slowing down their charging speed relative to the battery clusters with lower charge levels and thus narrowing the charge difference between the battery clusters. Alternatively, the main control module can increase the discharging current of these battery clusters during discharging, thereby increasing their discharging speed relative to the battery clusters with lower charge levels and thus narrowing the charge difference between the battery clusters.

[0127] Understandably, the main control module may select some battery clusters from the various battery clusters that have lower states of charge (SOC). For these battery clusters, during charging, the main control module controls the DC / DC converter to increase the charging current, thereby accelerating the charging speed of the battery clusters with lower SOC and achieving SOC balance. During discharging, the main control module controls the DC / DC converter to decrease the discharging current, thereby slowing down the discharging speed of the battery clusters with lower SOC and achieving SOC balance.

[0128] Taking a battery system consisting of m battery cells, with a preset quantity of n, as an example, the main control module can calculate the charging current of the n battery cells with higher state of charge values ​​according to the following formula during charging:

[0129] I1 = α * (total current - (mn) * maximum allowable current per cluster) / n;

[0130] Here, α is a preset safety margin, for example, 0.95. That is, the main control module needs to maintain the charging current of the battery cells other than the determined n battery cells at the maximum allowable current, while keeping the total current constant. The charging current of these n battery cells is calculated based on the remaining current after the total current is distributed among the other battery cells using the maximum allowable current. After calculating the charging current I1 corresponding to the n battery cells, the main control module can send a first current limit command containing I1 to the DC / DC conversion module of these n battery cells, so that the n battery cells operate at a constant current of I1. It can be understood that at this time, the battery clusters in other battery cells with lower state of charge (SOC) maintain the maximum allowable charging current, and their charging speed is faster than that of the battery clusters in the n battery cells. This makes the SOC of the other battery clusters approach the SOC of the n battery cells, thus causing the SOC of each battery cluster to gradually converge during charging.

[0131] It is understandable that when the DC / DC conversion module is switched on and the charging current of the branch containing the battery cell is kept at I1, I1 should be less than the charging current of the branch containing the battery cell when the DC / DC conversion module is not switched on, so that the DC / DC conversion module can reduce the charging speed of that part of the battery cluster when it is switched on.

[0132] Similarly, the main control module calculates the discharge current of the n battery cells with higher state of charge values ​​according to the following formula when the battery is in discharge mode:

[0133] I2 = α * maximum allowable current per cluster;

[0134] That is, the main control module can send a second current limit command containing I2 to n battery cells while keeping the total current constant, so that the n battery cells operate at a constant current of I2. It can be understood that at this time, the n battery cells discharge at the maximum permissible discharge current, and their state of charge (SOC) decreases faster than that of other battery cells with lower SOC. Therefore, by controlling the battery cells with higher SOC to discharge rapidly, the SOC of each battery cluster gradually converges during discharge.

[0135] It is understandable that when the DC / DC conversion module is switched on and the discharge current of the branch containing the battery cell is kept at I2, I2 should be greater than the discharge current of the branch containing the battery cell when the DC / DC conversion module is not switched on, so that the DC / DC conversion module can increase the discharge rate of that part of the battery cluster when it is switched on.

[0136] According to some embodiments of this application, please refer to Figure 6 Following S140 above, it may also include:

[0137] S310, the battery cluster whose state of charge value meets the cutoff condition is identified as the cutoff battery cluster;

[0138] S320 reduces the total operating power based on the current operating power of the cutoff battery cluster;

[0139] S330: Reduce the current of the cut-off battery cluster until the current of the cut-off battery cluster reaches the safe current range, then disconnect the branch switch corresponding to the battery cell where the cut-off battery cluster is located.

[0140] The main control module can perform current control on the DC / DC conversion modules in the control section. When the state of charge (SOC) of each battery cluster reaches equilibrium, the output terminals of that DC / DC conversion module are short-circuited to switch it out. After all the DC / DC conversion modules that were in operation have been switched out, the battery system will enter the end-of-charge / discharge region during continued charging or discharging. For example, when the SOC of a battery cluster reaches above 80% during charging or below 20% during discharging, each battery cluster will reach the charging or discharging cutoff condition during continued charging or discharging.

[0141] In S310, within the end-of-charge / discharge zone, the main control module detects the state of charge (SOC) value of each battery cluster. When the SOC value of a particular battery cluster meets a cutoff condition, it identifies that battery cluster as a cutoff battery cluster. Meeting the cutoff condition means that the SOC value of the battery cluster reaches 100% during charging or reaches 0% during discharging. This cutoff condition can also be that the battery cluster voltage reaches an upper limit voltage value during charging, such as 3.65V; or that the battery cluster voltage reaches a lower limit voltage value during discharging, such as 2.8V. In other words, the cutoff condition can be a trigger condition for the battery cluster to exit the charging / discharging process.

[0142] When the main control module detects that a certain battery cluster meets the cutoff condition, it can request to reduce the total operating power, and after reducing the total operating power, it can adjust the cutoff cluster according to whether the current state is charging or discharging.

[0143] In S320, after determining the cutoff battery clusters, the main control module can adjust the total operating power based on the current operating power of the cutoff battery clusters to reduce the total operating power. For example, after determining the cutoff battery clusters, the main control module can determine the number of battery clusters that are still operating. If the number of battery clusters that are still operating is X, the main control module can reduce the total operating power by 1 / X.

[0144] In S330, after the main control module reduces the total operating power based on the number of remaining operating battery clusters, it can reduce the battery cluster current of the cut-off battery cluster until the battery cluster current of the cut-off battery cluster is reduced to a safe current range. Then, the main control module can control the branch switch corresponding to the battery cell where the cut-off battery cluster is located to open, so that the battery cell where the cut-off battery cluster is located exits the charging and discharging process.

[0145] Understandably, when the DC / DC converter module in a battery cell has both positive and negative voltage output capabilities, the main control module can directly control the DC / DC converter module corresponding to the cut-off battery cluster to output a negative voltage compensation voltage, thereby reducing the battery cluster current of that cut-off battery cluster. When the DC / DC converter module in a battery cell only has a positive voltage output capability, the main control module can control the DC / DC converter modules of other battery cells to output compensation voltage, thereby increasing the battery cluster current of those other battery clusters and thus reducing the battery cluster current of the cut-off battery cluster.

[0146] During the process of controlling the reduction of the cutoff cluster current, the main control module can also detect whether the low-voltage side current of the DC / DC conversion module is zero. If the low-voltage side current of the DC / DC conversion module reaches or approaches zero, the DC / DC conversion module can be controlled to switch to an unloaded standby state, and the cutoff operation will be performed on each cutoff cluster in sequence until the last cluster is cut off. Optionally, when the first cutoff cluster is cut off, the main control module can record the current bus voltage. If, during subsequent operation, the bus voltage is detected to be higher than the recorded voltage and the voltage difference exceeds a set threshold, such as 15V, the module can request to stop charging and discharging, and after confirming the stop, it will enter the power-down process to stop the charging and discharging of the battery system.

[0147] When multiple battery clusters act as cutoff clusters in sequence and complete the cutoff adjustment, all battery clusters are in a fully charged or fully discharged state; however, when the bus voltage is too high and the system stops charging and discharging prematurely, not all battery clusters are in a fully charged or fully discharged state.

[0148] According to some embodiments of this application, after the main control module determines that the battery cluster is to be cut off, it can also use the compensation voltage output by the DC / DC conversion module within the voltage regulation range of the DC / DC conversion module to make the battery cluster maintain 0 current operation.

[0149] In this embodiment, if keeping the battery cluster operating at 0 current exceeds the voltage regulation range of the DC / DC conversion module, the above-mentioned method of reducing the total operating power and cutting off the battery cluster current to a safe current range is adopted. This is achieved by disconnecting the corresponding branch switch after the current of the cut-off battery cluster enters the safe current range, thereby disconnecting the cut-off battery cluster.

[0150] According to some embodiments of this application, please refer to Figure 7Before S110 above, it may also include:

[0151] S410 acquires the battery cluster voltage of each battery cell before the battery system is charged or discharged.

[0152] S420 determines the compensation voltage corresponding to each DC / DC conversion module based on the battery cluster voltage of each battery cluster.

[0153] S430 controls the output of corresponding compensation voltage for each DC / DC conversion module;

[0154] S440 controls the branch switches of each battery cell to turn on when the total output voltage of each branch reaches equilibrium.

[0155] In S410, after receiving a power-on request, the main control module can control the branch switches in each battery cell to turn on, thereby initiating the charging or discharging of the battery system. Before the battery system charges or discharges, i.e., before the main control module controls the branch switches to turn on, the main control module can obtain the battery cluster voltage of each battery cell.

[0156] In the S420, after acquiring the battery cluster voltages of each battery cluster, the main control module can determine the compensation voltage for each DC / DC conversion module based on the voltage differences between the battery cluster voltages. For example, the main control module can compare the battery cluster voltages of each battery cluster with the standard battery cluster voltage and calculate the voltage difference between the two. This voltage difference is the compensation voltage for the DC / DC conversion module corresponding to each battery cluster.

[0157] In the S430, after determining the compensation voltage for each DC / DC conversion module, the main control module can send voltage adjustment commands containing the compensation voltage to each DC / DC conversion module. This controls each DC / DC conversion module to convert the input voltage to the compensation voltage before outputting it according to the voltage adjustment commands. In each battery cell, the sum of the battery cluster voltage and the compensation voltage output by the DC / DC conversion module is the total output voltage. By controlling the voltage adjustment of each DC / DC conversion module, the total output voltage of each battery cell can be kept consistent or very close. This reduces internal circulating current when battery cells are connected in parallel, thus minimizing the risk of damage to the battery system.

[0158] It is understandable that the standard battery cluster voltage can be the average of the voltages of all battery clusters, or it can be the maximum or minimum battery cluster voltage. If the standard battery cluster voltage is the average of the voltages of all battery clusters, then when the battery cluster voltage is greater than the average, the compensation voltage output by the DC / DC converter module is a negative voltage; when the battery cluster voltage is less than the average, the compensation voltage output by the DC / DC converter module is a positive voltage. Therefore, when the DC / DC converter module has both positive and negative voltage output capabilities, the standard battery cluster voltage can be the average of the voltages of all battery clusters.

[0159] If the standard battery cluster voltage is the maximum battery cluster voltage, then the voltages of other battery clusters are all lower than the maximum battery cluster voltage. To maintain a balanced total output voltage across all battery cells, the DC / DC converter modules in the other battery cells need to output a positive compensation voltage, and the compensation voltage value is the difference between the maximum battery cluster voltage and the voltage of the battery cluster in that cell. Therefore, when the DC / DC converter module only has a positive voltage output capability, the standard battery cluster voltage can be the maximum battery cluster voltage, so that each DC / DC converter module outputs a positive compensation voltage to compensate for the voltage of battery clusters with voltages lower than the maximum battery cluster voltage.

[0160] In the S440, after controlling each DC / DC conversion module to output the corresponding compensation voltage, the main control module can determine that the total output voltage of each battery cell branch has reached equilibrium, and control the branch switches of each battery cell to conduct, so that each battery cell can be connected in parallel and start the charging or discharging process.

[0161] In this embodiment, by setting a main control module and connecting each battery cluster in series with a DC / DC conversion module, the main control module can detect and acquire the voltage of each battery cluster. Based on the voltage of each battery cluster, the main control module can determine the voltage difference between the battery clusters and calculate the compensation voltage for the corresponding DC / DC conversion module. By sending voltage adjustment commands containing the compensation voltage to each DC / DC conversion module, the main control module can make each DC / DC conversion module output the corresponding compensation voltage. The total output voltage of each battery cell is the sum of the battery cluster voltage and the compensation voltage. When there is a difference in the voltage of each battery cluster, by adjusting the value of the compensation voltage, the battery cluster voltage can be compensated, that is, the total output voltage of each battery cell can be kept balanced. When the total output voltage of each battery cell is kept balanced, the main control unit can control the branch switch to conduct to start the charging or discharging process. By compensating the voltage of each battery cluster before charging or discharging, the difference in the total output voltage between the battery cells can be reduced, the internal circulating current between the battery cells can be reduced, the risk of loops can be reduced, and the output efficiency of the battery system can be improved.

[0162] It should be noted that if one of the battery clusters in the battery system meets the cutoff condition, that is, when all battery clusters are controlled to stop charging or discharging, the voltage of each battery cluster remains consistent or relatively close. When the power is restored for discharging or charging, the voltage difference between each battery cluster is small, and the battery clusters can be directly connected in parallel.

[0163] If, in a battery system, when a certain battery cluster meets the cutoff condition, only that cluster is disconnected while the other clusters continue charging or discharging, resulting in all clusters being fully charged or fully discharged at the end of the charging or discharging process, then when the battery system is powered on again for discharging or charging, the inconsistency of the cells in each cluster leads to significant differences in the cluster voltages at full charge or discharge. In this case, the voltage difference between the clusters is large, and the clusters can only be connected in parallel after the total output voltage of each branch is balanced by the compensation voltage of the DC / DC converter module. That is, if all clusters are disconnected when the first cluster reaches the cutoff condition, the voltage difference between the clusters is small upon power-on, and no voltage compensation is needed; however, if the clusters reach the cutoff condition sequentially and disconnect sequentially, the voltage difference between the clusters is large upon power-on, requiring voltage balancing compensation.

[0164] According to some embodiments of this application, prior to S420 above, the control method of the battery system may further include:

[0165] S510, determine the maximum and minimum battery cluster voltage values ​​from the battery cluster voltages of each battery cluster;

[0166] When the difference between the maximum and minimum battery cluster voltage values ​​is greater than a preset voltage threshold, S420 is executed to determine the compensation voltage corresponding to each DC / DC conversion module based on the battery cluster voltage of each battery cluster.

[0167] S520 controls each DC / DC conversion module to turn on its bypass switch when the difference between the maximum and minimum battery cluster voltage values ​​is less than or equal to a preset voltage threshold.

[0168] S530 controls the branch switches of each battery cell to be turned on when the bypass switches of each battery cell are all turned on.

[0169] In the S510, the main control module can determine the maximum and minimum battery cluster voltage values ​​from the battery cluster voltages of each battery cluster.

[0170] When acquiring a preset voltage threshold, the main control module can determine whether the difference between the maximum and minimum battery cluster voltage values ​​exceeds this threshold. If the difference exceeds the threshold, it indicates a large voltage difference between the battery clusters. Without voltage compensation, significant internal circulating currents will occur between the battery cells due to this large voltage difference, potentially damaging them. In this case, the main control module needs to control each DC / DC converter to generate a corresponding compensation voltage to reduce the voltage difference between the battery cells and minimize the impact of internal circulating currents. The main control module can determine the compensation voltage for each DC / DC converter based on the battery cluster voltage value, and control each DC / DC converter to output the corresponding compensation voltage, ensuring that the total output voltage of each battery cell remains balanced under the compensation voltage.

[0171] In S520, if the difference between the maximum and minimum battery cluster voltage values ​​is less than or equal to a preset voltage threshold, the main control module can send a bypass command to each DC / DC conversion module to enable the DC / DC conversion module to control the bypass switch to turn on, short-circuiting the output terminal of the DC / DC conversion module, so that each battery cluster can be directly connected in parallel.

[0172] The preset voltage threshold is the voltage difference corresponding to the upper limit of the internal circulating current between battery cells. When the voltage difference between battery clusters exceeds this preset voltage threshold, direct parallel connection of battery clusters will result in a large internal circulating current, which can damage various components within the battery system due to excessive circulating current. In other words, when the voltage difference between battery clusters is large, direct parallel connection of battery clusters will generate excessive circulating current. Therefore, it is necessary to control the DC / DC conversion module to output a compensation voltage to reduce the voltage difference between battery cells, thus preventing the internal circulating current from affecting the internal components of the battery system.

[0173] In the S530, after the main control module controls the bypass switch of each battery cell to be turned on, it can control the branch switch of each battery cell to be turned on, so that the battery clusters of each battery cell can be directly connected in parallel.

[0174] Before the battery system is powered on, the main control module calculates the difference between the voltage values ​​of the largest and smallest battery clusters. If this difference is large, the main control module controls each DC / DC converter to output a compensation voltage and then turns on the branch switches, allowing the battery clusters to be connected in parallel for charging or discharging under the compensation voltage, thus reducing the internal circulating current between the battery clusters. If the difference is small, the main control module controls each bypass switch to turn on, preventing the DC / DC converter from outputting a compensation voltage and turning on each bypass switch, allowing multiple battery clusters to be connected in parallel and begin charging and discharging. This avoids excessive internal circulating current and reduces the operating time of the DC / DC converters, thereby reducing system power consumption and improving the charging and discharging efficiency of the battery system.

[0175] Taking a preset voltage threshold of 20V as an example, if the difference is greater than 20V, it indicates that the voltage difference between the battery clusters is large, and compensation voltage needs to be output by each DC / DC conversion module. If the difference is less than or equal to 20V, the voltage difference between the battery clusters is small, and the DC / DC conversion modules can be switched off by turning on the bypass switch. In this case, the battery clusters are directly connected in parallel.

[0176] According to some embodiments of this application, the above-described S420 may include:

[0177] S610, determine the maximum battery cluster voltage value and the battery cell corresponding to the maximum battery cluster voltage value from the battery cluster voltages of each battery cluster;

[0178] S620 uses the minimum compensation voltage of the DC / DC conversion module as the compensation voltage of the DC / DC conversion module in the battery cell corresponding to the maximum battery cluster voltage value.

[0179] S630 calculates the compensation voltage of the DC / DC conversion module in each battery cell based on the difference between the battery cluster voltage of each battery cell other than the battery cell corresponding to the maximum battery cluster voltage value and the maximum battery cluster voltage value.

[0180] In S610, when the main control module determines the compensation voltage output by each DC / DC conversion module based on the battery cluster voltage of each battery cluster, it can determine the maximum battery cluster voltage value and its corresponding battery cell from the battery cluster voltages of each battery cluster. For other battery clusters, the main control module can determine the difference between the compensation voltage output by the DC / DC conversion module of that battery cluster and the compensation voltage output by the DC / DC conversion module in the battery cell corresponding to the maximum battery cluster voltage value, based on the difference between the battery cluster voltage of that battery cluster and the maximum battery cluster voltage value.

[0181] In the S620, the DC / DC converter module outputs a compensation voltage within a certain voltage range. To ensure that other DC / DC converter modules can output appropriate compensation voltages, the main control module can set the compensation voltage output by the DC / DC converter module in the battery cell corresponding to the maximum battery cluster voltage as the minimum compensation voltage. Therefore, when the battery cluster voltage of other battery clusters is lower than the maximum battery cluster voltage, the compensation voltage output by the corresponding DC / DC converter module needs to be greater than the minimum compensation voltage to compensate for the voltage difference.

[0182] In the S630, the main control module can determine the difference between the battery cluster voltage in each battery cell and the maximum battery cluster voltage, and use the sum of this difference and the minimum compensation voltage as the compensation voltage of the corresponding DC / DC converter module. For example, if the difference between the battery cluster voltage in a certain battery cell and the maximum battery cluster voltage is 3V, and the minimum compensation voltage of the DC / DC converter module is 5V, then the compensation voltage of the DC / DC converter module corresponding to that battery cell is 8V, and the compensation voltage of the DC / DC converter module corresponding to the maximum battery cluster voltage is 5V. This ensures that the battery cluster voltage of that battery cell, after compensation by the DC / DC converter module, is consistent with or very close to the total output voltage of the battery cell corresponding to the maximum battery cluster voltage. After the main control module determines the compensation voltage of each DC / DC converter module based on the battery cluster voltage of each battery cell, the total output voltage of each battery cell can remain balanced under the compensation of the DC / DC converter module.

[0183] When there is a compensation voltage output range in the DC / DC conversion module, the main control module sets the DC / DC conversion module corresponding to the maximum battery cluster voltage value to the minimum compensation voltage. It can determine the actual compensation voltage of each DC / DC conversion module based on the difference between the battery cluster voltage in other battery cells and the maximum battery cluster voltage value, so that the total output voltage of each battery cell can remain balanced after being compensated by the DC / DC conversion module.

[0184] The following explanation uses a battery system comprising three battery clusters, A, B, and C, as an example. Because each battery cluster has different charging and discharging efficiencies, the time it takes for each cluster to reach its cutoff condition during charging and discharging varies. In other words, the time it takes for each battery cluster to complete discharging or charging differs.

[0185] When a battery cluster is charging and discharging, it can be sequentially divided into a charge / discharge initiation region, a plateau region, and a charge / discharge termination region. These regions can be defined based on the battery cluster's state of charge (SOC). For example, the SOC can be divided using 20% ​​and 80%, or other values ​​can be used; no restriction is placed here. When using 20% ​​and 80% as the dividing points, if the battery cluster is in a charging state, the charge / discharge initiation region, plateau region, and charge / discharge termination region are 0-20%, 20%-80%, and 80%-100%, respectively; if the battery cluster is in a discharging state, the charge / discharge initiation region, plateau region, and charge / discharge termination region are 100%-80%, 80%-20%, and 20%-0%, respectively.

[0186] In a battery system without a DC / DC conversion module and where battery clusters are directly connected in parallel, if one battery cluster reaches a reduced charging / discharging power or a cutoff condition, the other battery clusters in the entire system will also simultaneously reduce their charging / discharging power or cut off. For example, when cluster A reaches its cutoff condition, even if clusters B and C are not fully charged or discharged, the entire battery system will stop charging / discharging because cluster A has reached its cutoff condition. At this time, neither clusters B nor C has reached a fully charged or fully discharged state.

[0187] By connecting DC / DC converter modules in series with each battery cluster, the current of some battery clusters (A, B, and C) can be adjusted during the charging and discharging process, thus maintaining a balanced state of charge (SOC) value among the three clusters. Understandably, due to parameter limitations of the DC / DC converter module, it typically balances the SOC value of each battery cluster during the plateau phase of charging and discharging by adjusting the charging or discharging current. Through the balancing adjustment of the DC / DC converter module, when the three battery clusters A, B, and C move from the plateau phase to the end of the charging / discharging phase, their SOC values ​​remain consistent or very close. This ensures that when one of the three battery clusters reaches its cutoff condition in the end of the charging / discharging phase, the difference in SOC value between the other two battery clusters and the cluster that has reached its cutoff condition is reduced.

[0188] Furthermore, when one of the three battery clusters A, B, and C meets the cutoff condition, by reducing the total operating power and controlling the safe disconnection of the cutoff battery cluster, the remaining battery clusters that have not met the cutoff condition can continue to be charged or discharged until all three battery clusters A, B, and C reach a fully charged or fully discharged state, at which point the charging and discharging process ends.

[0189] A complete charging process can be divided into four stages: pre-power-on, charging / discharging initiation zone, plateau zone, and charging / discharging termination zone. The following is a detailed explanation of these four stages.

[0190] Please refer to Figure 8 Before power-on, the main control module receives a power-on request, at which point the branch switches of each battery cell are open. The main control module can acquire the battery cluster voltage of each battery cluster and determine whether to control the DC / DC converter module to output a compensation voltage based on the voltage difference. For example, the main control module can calculate the difference between the maximum and minimum battery cluster voltages. If the difference reaches a preset voltage threshold, the main control module will control the DC / DC converter module to output a compensation voltage; if the difference does not reach the preset voltage threshold, the bypass switch will be turned on, and the DC / DC converter module will not operate.

[0191] After the main control module controls each DC / DC conversion module to compensate for the battery cluster voltage or controls the bypass switch to turn on so that the battery clusters are connected in hard parallel, the main control module can control the branch switch of each battery cell to turn on so that the battery cells are connected in parallel and power on.

[0192] During the initial charging / discharging phase, the main control module can send a voltage regulation command to the DC / DC converter module corresponding to the battery cluster with the highest voltage, and a current regulation command to other DC / DC converter modules. When a DC / DC converter module receives a voltage regulation command, it outputs the minimum compensation voltage to the battery cluster with the highest voltage. When a DC / DC converter module receives a current regulation command, it can determine the corresponding current regulation value based on the command and control the current at its low-voltage end, thus maintaining the charging current of the branch containing the battery cluster at that current regulation value.

[0193] Before entering the platform zone, the main control module can control each DC / DC conversion module to turn on its corresponding bypass switch, thus switching the DC / DC conversion module out of operation. During the charge / discharge initiation zone, the main control module can monitor the voltage of each battery cluster in real time and calculate the difference between the maximum and minimum battery cluster voltages.

[0194] When the difference is greater than the cut-out threshold, the main control module can control each DC / DC conversion module to adjust the compensation voltage to the minimum compensation voltage when entering the platform area stage, and control each bypass switch to be turned on according to the preset rules so that each DC / DC conversion module can be cut out for operation.

[0195] When the difference is less than or equal to the cut-out threshold, the main control module can directly control each bypass switch to be turned on according to the preset rules so that each DC / DC conversion module can be cut out for operation.

[0196] The aforementioned cut-out threshold can be 3V or other voltage values. When the voltage difference between battery clusters exceeds this threshold, the main control module will not control the DC / DC conversion module to switch off operation until the platform phase is reached. Conversely, when the voltage difference between all battery clusters is less than the threshold, the main control module can control the DC / DC conversion module to switch off operation during the charge / discharge initiation phase. A preset rule could be to control the corresponding DC / DC conversion module to switch off operation sequentially according to the current magnitude of each battery cluster.

[0197] Please refer to Figure 9 During the platform phase, the main control module has already controlled the various DC / DC conversion modules to switch off operation. In the initial stage of the platform phase, the battery clusters are directly connected in hard parallel. The main control module can determine whether to balance the state of charge (SOC) values ​​of the battery clusters based on the differences in SOC values. For example, the main control module can calculate the difference between the maximum and minimum SOC values. If this difference is less than a balancing threshold, the main control module does not need to balance the SOC values ​​of the battery clusters; if the difference is greater than the balancing threshold, the main control module can balance the SOC values ​​of the battery clusters. The balancing threshold can be 10, meaning that when the difference between the maximum and minimum SOC values ​​is greater than 10, the main control module can control some DC / DC conversion modules to switch on to achieve SOC balance.

[0198] When the difference exceeds the balancing threshold, the main control module can select a subset of battery clusters from multiple battery clusters for balancing adjustment. These battery clusters can be those with higher state of charge (SOC), those with lower SOC, or those with a larger deviation from the average SOC value.

[0199] Taking a battery cluster with a high state of charge (SOC) value as an example, after identifying a portion of the battery clusters with a high SOC value from multiple battery clusters, the main control module can control the DC / DC conversion module corresponding to that portion of the battery clusters to reduce the charging current of the battery clusters, thereby slowing down the charging speed of the battery clusters with a high SOC value, so that the SOC values ​​of each battery cluster gradually approach each other during the charging process.

[0200] During the platform phase, the main control module can also calculate the real-time average value of the state of charge (SOC) of each battery cluster. When the SOC of a battery cluster matches this average value, the main control module can control the corresponding bypass switch to turn on, causing the DC / DC conversion module to switch off operation. As the SOC values ​​of each battery cluster successively reach the average value, the main control module can sequentially control each DC / DC conversion module to switch off operation until all DC / DC conversion modules are switched off operation.

[0201] Please refer to Figure 10During the final stage of charging and discharging, all DC / DC conversion modules are switched off, and the battery clusters are directly connected in parallel. During the charging process in this final stage, if a battery cluster meets the cutoff condition, it is designated as a cutoff battery cluster, and the total operating power is reduced based on the number of still-operating battery clusters. After reducing the total operating power, the main control module can control each DC / DC conversion module corresponding to that battery cluster to enter zero-current operation, and disconnect the branch switch corresponding to that battery cluster when the low-voltage current of each DC / DC conversion module drops to zero.

[0202] When controlling each DC / DC conversion module to operate at zero current, if the low-voltage current of the DC / DC conversion module drops to zero, the corresponding branch switch of that battery cluster can be opened to disconnect that battery cluster. If the low-voltage current of the DC / DC conversion module cannot drop to zero, and the output power of the DC / DC conversion module does not exceed the limit, the main control module can control the branch switch to disconnect under load. If the low-voltage current of the DC / DC conversion module cannot drop to zero, and the output power of the DC / DC conversion module exceeds the limit, the main control module needs to request a charging stop and control the entire battery system to stop.

[0203] When each battery cluster reaches its cutoff condition, the main control module can control the corresponding DC / DC conversion module to enter zero-current operation, and disconnect the battery cluster that has reached the cutoff condition when the current drops to 0. At this time, each battery cluster can reach a fully charged state.

[0204] After the first battery cluster reaches its cutoff condition and disconnects when the current drops to 0, the main control module can record the current bus voltage and monitor the difference between the real-time bus voltage and the recorded voltage during subsequent operation. When this difference exceeds a set threshold, for example, when the real-time bus voltage is higher than the recorded voltage and the difference reaches 15V, the main control module can control all DC / DC conversion modules to operate at zero current and send a power-down request to stop the battery system from charging. If the system prematurely stops charging and discharging due to excessively high bus voltage, not all battery clusters will be in a fully charged or fully discharged state.

[0205] A complete discharge process can also include four stages: pre-power-on, charge / discharge initiation zone, plateau zone, and charge / discharge termination zone. The implementation methods for each stage are similar to those for their corresponding stages in the charging process, and will not be described in detail here.

[0206] Figure 11 A schematic diagram of the hardware structure of the control device for the battery system provided in an embodiment of this application is shown.

[0207] The control device for the battery system may include a processor 1101 and a memory 1102 storing computer program instructions.

[0208] Specifically, the processor 1101 may include a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of this application.

[0209] Memory 1102 may include mass storage for data or instructions. For example, and not limitingly, memory 1102 may include a hard disk drive (HDD), floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, or Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, memory 1102 may include removable or non-removable (or fixed) media. Where appropriate, memory 1102 may be internal or external to the integrated gateway disaster recovery device. In a particular embodiment, memory 1102 is non-volatile solid-state memory.

[0210] Memory may include read-only memory (ROM), random access memory (RAM), disk storage media devices, optical storage media devices, flash memory devices, and electrical, optical, or other physical / tangible memory storage devices. Therefore, typically, memory includes one or more tangible (non-transitory) readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the methods according to one aspect of this disclosure.

[0211] The processor 1101 reads and executes computer program instructions stored in the memory 1102 to implement any of the battery system control methods in the above embodiments.

[0212] In one example, the control device for the battery system may further include a communication interface 1103 and a bus 1110. For example, Figure 11 As shown, the processor 1101, memory 1102, and communication interface 1103 are connected through bus 1110 and complete communication with each other.

[0213] The communication interface 1103 is mainly used to realize communication between various modules, devices, units and / or equipment in the embodiments of this application.

[0214] Bus 1110 includes hardware, software, or both, that couples components of the battery system's control devices together. For example, and not limitingly, the bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), HyperTransport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an Infinite Bandwidth Interconnect, a Low Pin Count (LPC) bus, a memory bus, a Microchannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or other suitable buses, or combinations of two or more of these. Where appropriate, bus 1110 may include one or more buses. Although specific buses are described and illustrated in embodiments of this application, any suitable bus or interconnect is contemplated herein.

[0215] The control device for this battery system can be based on the aforementioned battery system, thereby achieving integration. Figures 4 to 7 The control method for the battery system is described.

[0216] Furthermore, in conjunction with the battery system control methods in the above embodiments, this application embodiment can provide a computer storage medium for implementation. This computer storage medium stores computer program instructions; when these computer program instructions are executed by a processor, they implement any of the battery system control methods in the above embodiments.

[0217] The functional blocks shown in the above block diagram can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this application are programs or code segments used to perform the required tasks. The programs or code segments can be stored on a machine-readable medium or transmitted over a transmission medium or communication link via a first data signal carried in a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio frequency (RF) links, etc. Code segments can be downloaded via computer networks such as the Internet, intranets, etc.

[0218] It should be noted that, in this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0219] This document uses specific examples to illustrate the principles and implementation methods of this application. The examples are merely for the purpose of helping to understand the method and core ideas of this application. The above are only preferred embodiments of this application. It should be noted that due to the limitations of written expression, and the existence of an infinite number of specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principles of this application, and can also combine the above technical features in an appropriate manner. These improvements, modifications, changes, or combinations, or the direct application of the concept and technical solution of this application to other situations without modification, should all be considered within the scope of protection of this application.

Claims

1. A battery system, characterized in that, The battery system includes a main control module and multiple battery cells connected in parallel. Each battery cell includes: A battery cluster comprising multiple batteries connected in series, wherein a first end of the battery cluster is connected to a first common node; A DC / DC converter module, wherein the first output terminal of the DC / DC converter module is connected to the second terminal of the battery cluster, and the second output terminal of the DC / DC converter module is connected to the second common node; the first input terminal of the DC / DC converter module is connected to the first terminal of the battery cluster, and the second input terminal of the DC / DC converter module is connected to the second terminal of the battery cluster. A bypass switch, wherein the first terminal of the bypass switch is connected to the first output terminal of the DC / DC conversion module, and the second terminal of the bypass switch is connected to the second output terminal of the DC / DC conversion module; The main control module is used to determine a portion of the battery clusters based on the state of charge value of each battery cluster during charging or discharging, and control the corresponding DC / DC conversion modules of the battery clusters to control the charging current or discharging current, so as to reduce the difference in state of charge value between the battery clusters during charging or discharging. The main control module is also used to short-circuit the first and second output terminals of the partial DC / DC conversion module when the difference in state of charge values ​​between the various battery clusters meets the balancing condition, and reduce the total operating power according to the current operating power of the cut-off battery cluster. The cut-off battery cluster is the battery cluster whose state of charge value meets the cut-off condition. The cut-off condition is the trigger condition for the battery cluster to exit charging and discharging during the charging and discharging process.

2. The battery system according to claim 1, characterized in that, The control terminal of the bypass switch is connected to the bypass control terminal of the DC / DC conversion module; The main control module is used to send bypass commands or load operation commands to the DC / DC conversion module, so that the DC / DC conversion module controls the bypass switch to be turned on according to the bypass command or controls the bypass switch to be turned off according to the load operation command.

3. The battery system according to claim 2, characterized in that, The main control module is also used to send a voltage adjustment command to the DC / DC conversion module according to the battery cluster voltage of the battery cluster in each battery cell, so as to keep the total output voltage of the branch where each battery cell is located balanced.

4. The battery system according to claim 3, characterized in that, The battery cell also includes: A branch switch, which is connected in series with the battery cluster, is in an open state before charging or discharging; The main control module is also used to send voltage adjustment commands to each DC / DC conversion module before charging or discharging, and to control the branch switches of each battery cell to be turned on when the total output voltage of each battery cell branch is kept balanced.

5. A control method for a battery system, characterized in that, The main control module applied to the battery system according to any one of claims 1-4, wherein the control method of the battery system includes: During the charging or discharging of the battery system, the state of charge value of the battery cluster in each battery cell is obtained; Determine a subset of battery clusters based on the state of charge (SOC) values ​​of each cluster. The DC / DC conversion modules corresponding to the battery clusters are controlled to perform current control on the charging current or discharging current, so as to reduce the difference in state of charge value between the battery clusters during the charging or discharging process. When the state of charge of each battery cluster reaches equilibrium, the first and second output terminals of the partial DC / DC conversion module are short-circuited.

6. The control method for the battery system according to claim 5, characterized in that, The step of determining a subset of battery clusters based on the state of charge (SOC) value of each battery cluster includes: A preset number of battery clusters are selected from high to low based on their state of charge values. The control of the DC / DC conversion modules corresponding to the battery clusters to perform current control on the charging or discharging current, in order to reduce the difference in state of charge between the battery clusters during charging or discharging, includes: When the battery system is charging, the DC / DC conversion module corresponding to a preset number of battery clusters is controlled to disconnect the bypass switch and reduce the charging current of the branch. When the battery system is discharging, the DC / DC conversion module corresponding to a preset number of battery clusters is controlled to disconnect the bypass switch and increase the discharge current of the branch.

7. The control method for the battery system according to claim 5, characterized in that, After short-circuiting the first and second output terminals of the partial DC / DC conversion module when the state of charge values ​​of each battery cluster reach equilibrium, the method further includes: The battery cluster whose state of charge value meets the cutoff condition is identified as the cutoff battery cluster; Reduce the total operating power based on the current operating power of the cut-off battery cluster; Reduce the current of the cut-off battery cluster until it reaches a safe current range, then disconnect the branch switch corresponding to the battery cell containing the cut-off battery cluster.

8. The control method for the battery system according to claim 7, characterized in that, Before acquiring the state of charge (SOC) value of each battery cluster in the battery cell during charging or discharging of the battery system, the method further includes: Before charging or discharging the battery system, the battery cluster voltage of each battery cell is obtained; The compensation voltage for each DC / DC conversion module is determined based on the battery cluster voltage of each battery cluster. Control the output of each DC / DC conversion module to provide the corresponding compensation voltage; When the total output voltage of each battery cell's branch reaches equilibrium, the branch switch of each battery cell is turned on.

9. The control method for the battery system according to claim 8, characterized in that, Before determining the compensation voltage corresponding to each DC / DC conversion module based on the battery cluster voltage of each battery cluster, the method further includes: The maximum and minimum battery cluster voltage values ​​are determined from the battery cluster voltages of each battery cluster. When the difference between the maximum battery cluster voltage value and the minimum battery cluster voltage value is greater than a preset voltage threshold, the following steps are performed: determine the compensation voltage corresponding to each DC / DC conversion module based on the battery cluster voltage of each battery cluster; When the difference between the maximum and minimum battery cluster voltage values ​​is less than or equal to a preset voltage threshold, the bypass switches of each DC / DC conversion module are turned on. When the bypass switches of each battery cell are all turned on, the branch switches of each battery cell are turned on.

10. The control method for the battery system according to claim 5, characterized in that, The step of determining the compensation voltage corresponding to each DC / DC conversion module based on the battery cluster voltage of each battery cluster includes: The maximum battery cluster voltage value and the battery cell corresponding to the maximum battery cluster voltage value are determined from the battery cluster voltages of each battery cluster. The minimum compensation voltage of the DC / DC conversion module is used as the compensation voltage of the DC / DC conversion module in the battery cell corresponding to the maximum battery cluster voltage value; The compensation voltage of the DC / DC conversion module in each battery cell is calculated based on the difference between the battery cluster voltage of the battery cluster in each battery cell other than the battery cell corresponding to the maximum battery cluster voltage value and the maximum battery cluster voltage value.

11. A control device for a battery system, characterized in that, The control device of the battery system includes: a processor and a memory storing computer program instructions; When the processor executes the computer program instructions, it implements the control method of the battery system as described in any one of claims 5 to 10.

12. A computer storage medium, characterized in that, The computer storage medium stores computer program instructions, which, when executed by a processor, implement the control method of the battery system as described in any one of claims 5 to 10.

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