Power battery multi-branch control method and control system

Abstract

The invention discloses a power battery multi-branch control method and control system, and the method comprises the steps: determining that a plurality of power battery branches are fault-free and are not isolated; determining at least one of voltage difference values of different branch power batteries in the same group of battery systems, charge states of a plurality of branch power batteries and battery capacities of the plurality of branch power batteries; and controlling the working states of the branch power batteries according to at least one of the corresponding relationship between the plurality of voltage difference values and the preset difference value in the same group of battery systems, the charge state and the battery capacity, and the charge and discharge states of the plurality of branch power batteries. By adopting the scheme, the multi-branch differential control of the power battery of the single-group battery system is realized, the work of other branches of the same-group battery system is not influenced by the fault of one or more branches, the application of the power battery is maximized, the non-circulating-current stable operation of normal branches is ensured, and meanwhile, the control logic is formulated by combining the capacity of the power battery and the actual demand; and the multi-scene application requirements of the power battery are met.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the technical field of power locomotive control, in particular to a power battery multi-branch control method and a control system. BACKGROUND

[0002] In the prior art, in the case of single-branch or multi-branch fault in a single battery system, the method of isolating other available power battery branches is usually used to avoid the circulation between the power battery branches, at the cost of sacrificing the power availability for safety.

[0003] Due to the lack of control of the power battery high-voltage system on and off and charging and discharging, and the lack of response measures when the charging current fault caused by the branch circulation occurs, unnecessary power source loss and low response efficiency problems are caused, and the prior art cannot meet the needs of different application scenarios by combining the capacity of the power battery and the state of charge of the power battery. SUMMARY

[0004] The present application provides a power battery multi-branch control method and a control system. By differentiating the control of the power battery multi-branch of the single battery system, the precise isolation of the fault branch in the case of single-branch or multi-branch fault is realized, the normal branch is ensured to run stably without circulation, and the control logic is formulated by combining the capacity of the power battery and the actual demand, so as to meet the needs of multi-scene application of the power battery.

[0005] In the first aspect, the embodiment of the present application provides a power battery multi-branch control method, which comprises:

[0006] When it is determined that the plurality of power battery branches are fault-free and are not isolated, at least one of the voltage difference of the different branch power batteries in the same group battery system, the state of charge of the plurality of branch power batteries, and the battery capacity of the plurality of branch power batteries is determined.

[0007] In the same group battery system, at least one of the plurality of voltage differences and the preset difference, the state of charge, and the battery capacity, and the charging and discharging state of the plurality of branch power batteries are used to control the working state of the branch power battery.

[0008] Optionally, the working state of the branch power battery is controlled according to at least one of the plurality of voltage differences and the preset difference, the state of charge, and the battery capacity, and the charging and discharging state of the plurality of branch power batteries, comprising:

[0009] When the plurality of voltage differences are all greater than the preset difference and the branch power battery is discharging, the power battery branch in which the branch power battery with the maximum voltage value is located is closed.

[0010] Among the multiple unclosed power battery branches corresponding to multiple power batteries, the multiple power battery branches corresponding to multiple power batteries with voltage differences less than a preset value are closed in sequence according to the increasing voltage difference between them and the power battery with the largest voltage value.

[0011] Optionally, the operating state of the branch power battery is controlled based on at least one of the following: the correspondence between multiple voltage differences and preset differences, the state of charge, and the battery capacity, as well as the charging and discharging states of multiple branch power batteries, including:

[0012] When multiple voltage differences are greater than a preset difference and the branch power battery is charging, close the power battery branch containing the branch power battery with the lowest voltage among the multiple branch power batteries.

[0013] Among the multiple unclosed power battery branches corresponding to multiple power batteries, the multiple power battery branches corresponding to the multiple power batteries with voltage differences less than a preset value are closed in order of decreasing voltage difference with the power battery branch with the smallest voltage value.

[0014] Optionally, the operating state of the branch power battery is controlled based on at least one of the following: the correspondence between multiple voltage differences and preset differences, the state of charge, and the battery capacity, as well as the charging and discharging states of multiple branch power batteries, including:

[0015] When multiple voltage differences are all less than the preset difference and the number of power battery branches is increased, all the already powered charging and discharging units and power battery branches are sequentially powered off.

[0016] The power battery branch and charging / discharging unit that are fault-free and not isolated are powered on in sequence.

[0017] Optionally, after controlling the power supply of at least two battery branches as needed, it also includes:

[0018] Set a current sharing period and control the current of one power battery branch to be the first current and the current of the other power battery branch to be the second current during the current sharing period; the first current is greater than zero and the second current is less than zero.

[0019] During the current sharing period, overcurrent faults in any two power battery branches are filtered out.

[0020] Optionally, the operating state of the branch power battery is controlled based on at least one of the following: the correspondence between multiple voltage differences and preset differences, the state of charge, and the battery capacity, as well as the charging and discharging states of multiple branch power batteries, including:

[0021] When multiple branch power batteries are in discharge mode and the state of charge of any one of the multiple branch power batteries is less than the preset charge value, and the branch power battery is in power battery auxiliary power supply mode, power battery auxiliary machine test mode, power battery short distance motor mode, load self-propelled mode or no power return mode, all the charged and discharged units and power battery branches that have been powered on are controlled to be powered off in sequence. Then, the power battery branches and charged and discharged units that are in power battery auxiliary power supply mode, power battery auxiliary machine test mode, power battery short distance motor mode, load self-propelled mode or no power return mode and whose state of charge of the branch power battery is greater than the preset charge value are controlled to be powered on in sequence.

[0022] When multiple branch power batteries are in discharge mode and the state of charge of any one of the multiple branch power batteries is greater than the preset charge value, and the branch power battery is in power battery auxiliary power supply mode, power battery auxiliary machine test mode, power battery short distance motor mode, load self-propelled mode or no power return mode, the branch power battery is controlled to discharge.

[0023] When multiple branch power batteries are in discharge mode and the state of charge of multiple branch power batteries is less than the preset charge value, and the branch power batteries are in power battery auxiliary power supply mode, power battery auxiliary machine test mode, power battery short distance vehicle mode or load self-propelled mode, the system controls multiple branch power batteries to exit power battery auxiliary power supply mode, power battery auxiliary machine test mode, power battery short distance vehicle mode or load self-propelled mode, and does not allow branch power batteries that are not in power battery auxiliary power supply mode, power battery auxiliary machine test mode, power battery short distance vehicle mode or load self-propelled mode to enter the above modes.

[0024] When multiple branch power batteries are in a discharging state and the state of charge of multiple branch power batteries is less than the preset charge value, and the branch power batteries are in a no-power return mode, the system controls multiple branch power batteries to not exit the branch power battery discharge mode and allows branch power batteries that are not in the no-power return mode to enter the no-power return mode.

[0025] Optionally, the operating state of the branch power battery is controlled based on at least one of the following: the correspondence between multiple voltage differences and preset differences, the state of charge, and the battery capacity, as well as the charging and discharging states of multiple branch power batteries, including:

[0026] When the battery capacity is less than the preset capacity, the control branch power battery enters at least one of the following modes: power battery auxiliary power supply mode, power battery auxiliary machine test mode, or power battery short-distance vehicle mode.

[0027] Optionally, the multi-branch control method for the power battery also includes:

[0028] When it is determined that at least one power battery branch has a fault or is isolated, the power battery of the fault-free and non-isolated branch is controlled to enter at least one of the following modes: power battery auxiliary power supply mode, power battery auxiliary machine test mode, or power battery short-distance vehicle mode.

[0029] Optionally, the multi-branch control method for the power battery also includes:

[0030] When it is determined that at least one power battery branch has a fault or is isolated, all powered charging and discharging units and power battery branches that have been powered on are powered off in sequence.

[0031] The power battery branch and charging / discharging unit containing the fault-free and non-isolated branch power battery are powered on sequentially.

[0032] In a second aspect, embodiments of the present invention provide a multi-branch control system for a power battery, characterized in that it includes: a control module, at least one single battery system and at least one charging and discharging unit, wherein the single battery system includes at least one power battery branch;

[0033] The charging and discharging unit includes a charging and discharging unit working contactor, and the power battery branch includes a branch positive and negative contactor;

[0034] The control module is communicatively connected to the working contactor of the charging and discharging unit and the positive and negative contactors of the branch circuits. When it is determined that multiple power battery branches are fault-free and without isolation, the control module determines at least one of the following: the voltage difference of different power batteries in the same battery group system, the state of charge of multiple power batteries in the branch circuits, and the battery capacity of multiple power batteries in the branch circuits. Within the same battery group system, the control module controls the working state of the branch power batteries based on the correspondence between multiple voltage differences and preset differences, the state of charge and the battery capacity, and the charging and discharging state of multiple power batteries in the branch circuits.

[0035] This invention provides a multi-branch control method and control system for power batteries. By determining that multiple power battery branches are fault-free and without isolation, at least one of the following is determined within the same battery group system: voltage difference between different branches, state of charge (SOC) of multiple branches, and battery capacity. Then, based on the correspondence between multiple voltage differences within the same battery group system and preset differences, at least one of SOC and battery capacity, and the charging / discharging state of multiple branches, the operating state of the branch power batteries is controlled. Using this technical solution, differentiated control of multiple branches of a single battery group system achieves precise isolation of faulty branches in the event of a single or multiple branch failure, ensuring stable operation of normal branches without circulating current. Simultaneously, control logic is formulated based on the power battery capacity and actual needs to meet the requirements of power battery applications in various scenarios. This solves the problem of sacrificing power for safety protection when a single or multiple branch fails, resulting in wasted power source and the inability to dynamically control power battery branches according to actual working needs. Attached Figure Description

[0036] Figure 1 This is a flowchart of a multi-branch control method for a power battery provided by an embodiment of the present invention;

[0037] Figure 2 This is a flowchart of the second power battery multi-branch control method provided in the embodiments of the present invention;

[0038] Figure 3 This is a flowchart of the third power battery multi-branch control method provided in the embodiments of the present invention;

[0039] Figure 4 This is a flowchart of the fourth power battery multi-branch control method provided in the embodiments of the present invention;

[0040] Figure 5 This is a flowchart of the fifth power battery multi-branch control method provided in the embodiments of the present invention;

[0041] Figure 6 This is a flowchart of the sixth power battery multi-branch control method provided in the embodiments of the present invention;

[0042] Figure 7 This is a flowchart of the seventh multi-branch control method for power batteries provided in the embodiments of the present invention;

[0043] Figure 8 This is a flowchart of the eighth power battery multi-branch control method provided in the embodiments of the present invention;

[0044] Figure 9 This is a schematic diagram of a multi-branch control system for a power battery provided in an embodiment of the present invention.

[0045] In this embodiment of the invention, the reference numerals and corresponding feature names are as follows:

[0046] 1-Control module, 2-Branch positive and negative contactors, 10-Charging and discharging unit working contactor, 100-Charging and discharging unit, 20-Power battery branch, 200-Single battery system. Detailed Implementation

[0047] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0048] The terminology used in the embodiments of this invention is for the purpose of describing specific embodiments only and is not intended to limit the invention. It should be noted that directional terms such as "upper," "lower," "left," and "right" described in the embodiments of this invention are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this invention. Furthermore, in the context, it should be understood that when referring to an element being formed "upper" or "lower" of another element, it can be formed not only directly "upper" or "lower" of the other element, but also indirectly "upper" or "lower" of the other element through an intermediate element. The terms "first," "second," etc., are used for descriptive purposes only and do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0049] In the description of this application, unless otherwise expressly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0050] Figure 1 This is a flowchart of a multi-branch control method for a power battery according to an embodiment of the present invention. This embodiment is applicable to situations where multiple branches of a power battery are controlled for power-on / off and charging / discharging. The multi-branch control method for a power battery can be executed by a multi-branch control system for a power battery. Figure 1 As shown, the multi-branch control method for a power battery provided in this embodiment of the invention includes:

[0051] S101. When it is determined that multiple power battery branches are fault-free and not isolated, determine at least one of the following: voltage difference of power batteries in different branches within the same battery system, state of charge of multiple power batteries, and battery capacity of multiple power batteries.

[0052] Specifically, a power battery branch can be understood as an energy storage and power output unit within a single battery system, composed of multiple individual cells connected in series or parallel, and equipped with independent positive and negative contactors, enabling independent access to the main circuit of the system. Assuming that multiple power battery branches are fault-free and not isolated, and that all branches are in normal condition, at least one of the following should be determined: the voltage difference between the power batteries in different branches within the same battery system; the state of charge of the power batteries in multiple branches; and the battery capacity of the power batteries in multiple branches.

[0053] The voltage difference between different branches of the power battery in the same battery group can be understood as the voltage difference between every two power battery branches within the same battery group. For example, if there are three branches in the same battery group: branch A has a voltage of 3.630V, branch B has a voltage of 3.610V, and branch C has a voltage of 3.605V, then the voltage difference between branch A and branch B is 20mV, the voltage difference between branch B and branch C is 5mV, and the voltage difference between branch A and branch C is 25mV. The state of charge (SOC) of multiple power batteries can be understood as the percentage of the remaining usable capacity of the power battery at a certain moment relative to its rated capacity under the same conditions, reflecting the current remaining charge level of the battery. The battery capacity can be understood as the total amount of charge that the power battery can release under specified charge and discharge conditions, and can be used to measure the energy storage capacity of the power battery.

[0054] S102. Within the same battery system, the operating state of the branch power battery is controlled based on at least one of the following: the correspondence between multiple voltage differences and preset differences, the state of charge, and the battery capacity, as well as the charging and discharging states of multiple branch power batteries.

[0055] Specifically, the preset difference is initially set based on the power battery material and capacity, and then the final value of the preset difference is determined based on experimental results. Controlling the operating state of the branch power batteries based on the correspondence between multiple voltage differences and the preset difference, as well as the charging and discharging states of multiple branch power batteries, can be understood as setting a preset difference for the voltage difference between power battery branches. The voltage differences between different branch power batteries within the same battery group are compared with the preset difference to determine whether the voltage difference exceeds the preset difference. The control system determines the charging and discharging state of the power batteries and controls the power-on sequence of multiple power battery branches according to the charging and discharging state.

[0056] Controlling the operating state of branch power batteries based on their state of charge (SBC) and the charge / discharge states of multiple branch power batteries can be understood as setting an operating threshold for the SBC, monitoring whether the SBC of the operating power battery falls below the threshold, and controlling the operating state of the branch power batteries according to their charge / discharge states. Controlling the operating state of branch power batteries based on their battery capacity can be understood as controlling the power battery to enter different operating modes according to the current application scenario based on the capacity of the branch power battery itself.

[0057] The multi-branch control method for power batteries provided in this invention determines at least one of the following when multiple power battery branches are fault-free and without isolation: the voltage difference between different branches of the power batteries within the same battery group system, the state of charge (SOC) of the multiple branches, and the battery capacity of the multiple branches. Then, based on the correspondence between the multiple voltage differences within the same battery group system and a preset difference, at least one of the SOC and battery capacity, and the charging / discharging state of the multiple branches, the operating state of the branch power batteries is controlled. By employing this technical solution, differentiated control of multiple branches of the power batteries in a single battery group system achieves precise isolation of faulty branches in the event of a single or multiple branch failure, ensuring stable operation of normal branches without circulating current. Simultaneously, control logic is formulated based on the power battery capacity and actual needs to meet the requirements of power battery applications in multiple scenarios. This solves the problem of sacrificing power for safety protection when a single or multiple branch fails, resulting in wasted power and the inability to dynamically control the power battery branches according to actual working needs.

[0058] Figure 2 This is a flowchart of a second type of multi-branch control method for power batteries provided in this embodiment of the invention. This embodiment elaborates on a method described in the above embodiment for controlling the working state of branch power batteries based on the correspondence between multiple voltage differences and preset differences, as well as the discharge state of multiple branch power batteries. Figure 2 As shown, the method specifically includes:

[0059] S201. When it is determined that multiple power battery branches are fault-free and not isolated, determine at least one of the following: voltage difference of power batteries in different branches within the same battery system, state of charge of multiple power batteries, and battery capacity of multiple power batteries.

[0060] S202. When multiple voltage differences are greater than a preset difference and the branch power battery is discharging, close the power battery branch containing the branch power battery with the largest voltage value among the multiple branch power batteries.

[0061] Specifically, when multiple voltage differences are all greater than a preset difference, multiple power battery branches are energized. At this time, the energizing sequence of the multiple power battery branches is controlled according to the charging and discharging state of the branch power batteries. When the branch power batteries are discharging, the power battery branch containing the branch power battery with the highest voltage value among the multiple branch power batteries is closed first.

[0062] S203. Among the multiple power battery branches corresponding to the multiple unclosed power battery branches, the multiple power battery branches corresponding to the multiple power battery branches with voltage differences less than a preset value are closed in sequence according to the increasing voltage difference between them and the power battery branch with the largest voltage value.

[0063] Specifically, after closing the power battery branch containing the power battery with the highest voltage among multiple power battery branches, this power battery branch begins to discharge. The voltage will drop slightly through the discharge circuit. Then, the voltage difference between the power batteries in the unclosed power battery branches and the power batteries in the closed power battery branches is determined. Following the order of increasing voltage difference with the power battery branch with the highest voltage, the power battery branches corresponding to power batteries with voltage differences less than a preset value are closed sequentially.

[0064] For example, a battery system has three branches: branch A has a voltage of 3.640V, branch B has a voltage of 3.620V, and branch C has a voltage of 3.605V. A preset voltage difference value of 10mV is set. Therefore, the voltage difference between branch A and branch B is 20mV, the voltage difference between branch B and branch C is 15mV, and the voltage difference between branch A and branch C is 35mV. At this point, the voltage differences between the power battery branches are all greater than the preset difference. The power-on sequence of multiple power battery branches is controlled according to the charging and discharging state of the branch power batteries. When a branch power battery is discharging, branch A with the highest voltage value is closed first. As branch A discharges, the voltage drops through the discharge circuit. For example, when the voltage drops to 3.614V, the voltage difference between the other branches and branch A is then assessed. The voltage difference between branch B and branch A is 3.620V - 3.614V = 6mV < 10mV, which meets the preset difference condition. Branch B is then closed, and it begins to discharge, causing its voltage to drop. For example, when the voltage of branch B drops to 3.610V, the voltage difference between branch C and branch A is 3.614 - 3.605 = 9mV < 10mV, also meeting the preset difference condition. The voltage difference between branch C and branch B is 3.610V - 3.605V = 5mV < 10mV, again meeting the preset difference condition. Branch C is then closed, and ultimately all three branches are connected, achieving stable discharge.

[0065] The technical solution adopted in this invention involves first closing the power battery branch containing the power battery with the highest voltage among multiple branch power batteries when the voltage difference between multiple branch power batteries is greater than a preset value and the power battery is discharging. Then, among the multiple power batteries corresponding to the unclosed branch power batteries, the branch power batteries corresponding to the multiple branch power batteries that meet the condition of having a voltage difference less than a preset value are closed sequentially in order of increasing voltage difference with the branch power battery with the highest voltage value. This avoids the generation of large circulating currents caused by multiple branches being powered on simultaneously when multiple voltage differences are greater than the preset value. By rationally controlling the power-on sequence of multiple branches according to the voltage difference and charging / discharging state of each branch, safe parallel discharge of multiple branches is achieved, ensuring the safety of multi-branch discharge and solving the safety problem of power battery branches caused by circulating currents generated by direct parallel connection of high-voltage and low-voltage branches.

[0066] Figure 3 This is a flowchart of the third type of multi-branch control method for power batteries provided in this embodiment of the invention. This embodiment elaborates on a method described in the above embodiments for controlling the working state of branch power batteries based on the correspondence between multiple voltage differences and preset differences, as well as the charging state of multiple branch power batteries. Figure 3 As shown, the method specifically includes:

[0067] S301. When it is determined that multiple power battery branches are fault-free and not isolated, determine at least one of the following: voltage difference of power batteries in different branches within the same battery system, state of charge of multiple power batteries, and battery capacity of multiple power batteries.

[0068] S302. When multiple voltage differences are greater than a preset difference and the branch power battery is charging, close the power battery branch containing the branch power battery with the lowest voltage among the multiple branch power batteries.

[0069] Specifically, when multiple voltage differences are all greater than a preset difference, multiple power battery branches are energized. At this time, the energizing sequence of the multiple power battery branches is controlled according to the charging and discharging state of the branch power batteries. When the branch power batteries are charging, the power battery branch containing the branch power battery with the lowest voltage value among the multiple branch power batteries is closed first.

[0070] S303. Among the multiple power battery branches corresponding to the multiple unclosed power battery branches, the multiple power battery branches corresponding to the multiple power battery branches with voltage differences less than a preset value are closed in sequence according to the order of decreasing voltage difference with the power battery branch with the smallest voltage value.

[0071] Specifically, after closing the power battery branch containing the power battery with the lowest voltage among multiple power battery branches, this branch is charged first. During charging, the voltage gradually increases. Then, the voltage difference between the power batteries in the unclosed power battery branches and the power batteries in the closed power battery branches is determined. Following the order of decreasing voltage difference with the power battery in the branch with the lowest voltage, the power battery branches corresponding to power batteries with voltage differences less than a preset value are closed sequentially.

[0072] For example, a battery system has three branches: branch A has a voltage of 3.640V, branch B has a voltage of 3.620V, and branch C has a voltage of 3.605V. A preset voltage difference of 10mV is set. Therefore, the voltage difference between branch A and branch B is 20mV, the voltage difference between branch B and branch C is 15mV, and the voltage difference between branch A and branch C is 35mV. At this point, the voltage differences between the power battery branches are all greater than the preset difference. The power-on sequence of multiple power battery branches is controlled according to the charging and discharging state of the branch power batteries. During charging, branch C with the lowest voltage is closed first, and the charging and discharging unit charges branch C. The voltage of branch C gradually increases. For example, when the voltage of branch C rises to 3.612V, the voltage difference between the other branches and branch C is then assessed. The voltage difference between branch B and branch C is 3.620V - 3.612V = 8mV < 10mV, which meets the preset difference condition. Therefore, branch B is closed, and charging begins, causing the voltage to rise. For example, when the voltage of branch B rises to 3.635V, the voltage difference between branch A and branch B is 3.640 - 3.635 = 5mV < 10mV, meeting the preset difference condition. However, the voltage difference between branch A and branch C is 3.640V - 3.605V = 25mV > 10mV, which does not meet the preset difference condition. Therefore, branch A is not closed temporarily, and branches B and C continue charging until the voltage difference between branch A and branch C meets the preset difference condition. Then, branch A is closed, and all three branches are connected for stable charging.

[0073] This invention employs the above technical solution. When multiple voltage differences are greater than a preset difference and the branch power battery is charging, the power battery branch containing the branch power battery with the lowest voltage value is closed first. Then, among the unclosed power battery branches, the power battery branches corresponding to the multiple branch power batteries are closed sequentially in descending order of voltage difference with the branch power battery with the lowest voltage value, provided that the battery voltage difference is less than the preset difference condition. By rationally controlling the power-on sequence of multiple branches based on the voltage difference and charging / discharging state of each branch, reverse charging of low-voltage branches by high-voltage branches is avoided, improving charging efficiency and ensuring the safety of the power battery. This solves the charging safety hazard problem caused by direct parallel connection of high-voltage and low-voltage branches.

[0074] Figure 4 This is a flowchart of the fourth multi-branch control method for power batteries provided in this embodiment of the invention. This embodiment elaborates in detail on another method used in the above embodiments to control the working state of the branch power batteries based on the correspondence between multiple voltage differences and preset differences, as well as the charging and discharging states of multiple branch power batteries. Figure 4 As shown, the method specifically includes:

[0075] S401. When it is determined that multiple power battery branches are fault-free and not isolated, determine at least one of the following: voltage difference of power batteries in different branches within the same battery system, state of charge of multiple power batteries, and battery capacity of multiple power batteries.

[0076] S402. When multiple voltage differences are all less than the preset difference and the number of power battery branches that are powered on increases, control all the already powered charging and discharging units and power battery branches to power off in sequence.

[0077] Specifically, when multiple voltage differences are all less than a preset value, multiple power battery branches can be safely connected in parallel. Since the voltage differences meet the requirements, no circulating current is generated when multiple power battery branches are connected in parallel simultaneously. At this time, within the same battery system, when the operation changes from a single power battery branch to multiple power battery branches operating in parallel, the charging and discharging unit's working contactor and the branch's positive and negative contactors are disconnected sequentially to stop the charging and discharging unit from discharging and to de-energize all powered power battery branches.

[0078] S403 sequentially controls the power battery branch and charging / discharging unit that are fault-free and not isolated to be powered on.

[0079] Specifically, after confirming that the charging and discharging unit working contactor and the branch positive and negative contactor are completely disconnected, the branch positive and negative contactors and the charging and discharging unit working contactors of multiple power battery branches that can work normally are closed in sequence to control the power battery branches to be powered on and to charge or discharge, and the system resumes the parallel operation of multiple power battery branches.

[0080] For example, when there are three branches (branch A, branch B, and branch C) in the same battery system, the voltage difference between multiple branches is less than a preset difference, and branches B and C were previously automatically isolated due to faults, with only branch A operating. Now, the faults in branches B and C have been resolved. When the vehicle is in motion, and branch A is discharging and supplying power to the system independently, the system returns to simultaneous operation of all three power battery branches (branch A, branch B, and branch C). First, the charging / discharging unit's working contactor is disconnected, then the positive and negative contactors of branch A are disconnected, controlling the charging / discharging unit to stop discharging and simultaneously energizing branch A. After confirming that all contactors are completely disconnected, the positive and negative contactors of branches A, B, and C are closed. In this embodiment, the closing order of the positive and negative contactors of branches A, B, and C is not limited. Then, the charging / discharging unit's working contactor is closed, and branches A, B, and C simultaneously discharge to supply power to the moving vehicle, restoring the system to multi-branch operation.

[0081] In any of the above optional embodiments, the closing conditions for the branch positive and negative contactors are that the power battery branch itself is fault-free and has no isolation, the charging and discharging units within the same battery group are fault-free and have no isolation, and the associated equipment corresponding to different operating modes is fault-free and has no isolation. For example, the power battery short-distance vehicle mode and the load self-propelled mode require the corresponding vehicle traction inverter to be fault-free and have no isolation, while the discharging mode requires the corresponding vehicle auxiliary system to be fault-free and have no isolation. Simultaneously, the voltage difference between the branch power batteries must meet a preset difference requirement. For example, if multiple power battery branches are connected in parallel after closing, the voltage difference between all branches to be closed must be less than the preset difference; if only a single branch is closed, there is no voltage difference requirement.

[0082] This invention employs the above technical solution. When multiple voltage differences are all less than a preset difference and the number of power battery branches to be energized needs to be increased, all already energized power battery branches are de-energized. Then, at least two power battery branches are energized as needed. By first completely de-energizing and disconnecting all contactors, and then sequentially re-closing them, safe parallel connection of branches is achieved. This avoids direct energization causing current surges or circulating currents during branch switching, which could lead to branch faults and ensure the safety of restoring multi-branch parallel operation.

[0083] Figure 5This is a flowchart of the fifth power battery multi-branch control method provided in this embodiment of the invention. This embodiment elaborates in detail the steps after controlling at least two power battery branches to be powered on according to requirements in the above embodiments. Figure 5 As shown, the method includes:

[0084] S501. When it is determined that multiple power battery branches are fault-free and not isolated, determine at least one of the following: voltage difference of power batteries in different branches within the same battery system, state of charge of multiple power batteries, and battery capacity of multiple power batteries.

[0085] S502. When multiple voltage differences are all less than the preset difference and it is necessary to increase the number of power battery branches that are already powered on, control all power battery branches that are already powered on to shut down.

[0086] S503: Control the power supply of at least two power battery branches according to demand.

[0087] S504. Set the current sharing period and control the current of one power battery branch to be the first current and the current of the other power battery branch to be the second current during the current sharing period; the first current is greater than zero and the second current is less than zero.

[0088] Specifically, even if multiple voltage differences are all less than the preset difference, a slight circulating current will still exist when multiple branches are powered on and connected in parallel, and a charging overcurrent fault may occur during charging. For example, branches A, B, and C are connected in parallel and powered on. Branch A has an output current of +12A, branch B has an output current of -8A, and branch C has an output current of -4A. If the charging overcurrent threshold is set to 10A, the absolute value of the reverse charging current of branch B (8A < 10A) will not trigger a false alarm. However, if, due to branch differences, the reverse charging current of branch B reaches -16A, the system will mistakenly judge that branch B has a charging overcurrent, triggering protection and causing the system to malfunction. Therefore, overcurrent fault filtering can be performed by setting a current sharing period to distinguish between slight normal circulating current and abnormal overcurrent phenomena, thus solving the problem of false charging overcurrent alarms.

[0089] The rules for current direction are set, controlling the current in one power battery branch as the first current and the current in the other power battery branch as the second current during the current sharing period; the first current is greater than zero, and the second current is less than zero. The first current can be understood as the current direction in the discharge state of the power battery branch, and the second current can be understood as the current direction in the charging state of the power battery branch.

[0090] S505. During the current sharing period, filter overcurrent faults in any two power battery branches.

[0091] Specifically, when a branch current is detected to be at the first current and another branch current to be at the second current, it is determined that the current is in a current sharing period. A maximum current sharing limit is set. If the absolute value of the second current in a branch is greater than or equal to the set charging overcurrent threshold, but less than the set maximum current sharing limit, it is considered normal circulating current, and the overcurrent signal is filtered out without triggering fault protection. If either the first or second current in the power battery branch exceeds the maximum current sharing limit, it is considered abnormal overcurrent, and overcurrent protection is triggered.

[0092] This invention employs the above technical solution to address the overcurrent false alarm problem caused by multiple power battery branches being simultaneously powered on in parallel when multiple voltage differences are all less than a preset difference. By setting a current sharing period, the current of one power battery branch is controlled to be greater than zero while the current of another power battery branch is less than zero during this period. A maximum current sharing limit is set within the current sharing period, ensuring that overcurrent protection is triggered only when the first or second current of a power battery branch exceeds this limit. This design allows for slight circulating current during normal current sharing, preventing system interruptions caused by overcurrent false alarms and improving system stability. It also avoids actual overcurrent risks, reducing damage to the power battery branches and ensuring safe and stable operation after multiple branches are connected in parallel.

[0093] Figure 6 This is a flowchart of the sixth type of multi-branch control method for power batteries provided in this embodiment of the invention. This embodiment elaborates in detail on a method described in the above embodiments for controlling the operating state of a branch power battery based on the state of charge of multiple operating power battery branches and the charging and discharging state of the power batteries in multiple branches. Figure 6 As shown, the method specifically includes:

[0094] S601. When it is determined that multiple power battery branches are fault-free and not isolated, determine at least one of the following: voltage difference of power batteries in different branches within the same battery system, state of charge of multiple power batteries, and battery capacity of multiple power batteries.

[0095] S602. When multiple branch power batteries are in discharge mode and the state of charge of any one of the multiple branch power batteries is less than the preset charge value, and the branch power battery is in power battery auxiliary power supply mode, power battery auxiliary machine test mode, power battery short distance motor mode, load self-propelled mode or no power return mode, the power supply is sequentially controlled to shut down all the already powered charging and discharging units and power battery branches, and then the power battery branches and charging and discharging units in power battery auxiliary power supply mode, power battery auxiliary machine test mode, power battery short distance motor mode, load self-propelled mode or no power return mode and the state of charge of the branch power battery is greater than the preset charge value are sequentially controlled to be powered on.

[0096] Specifically, the system sets a preset charge value and monitors the state of charge of multiple branch power batteries. When multiple branch power batteries are in discharge mode and the state of charge of any branch power battery in operation is less than the preset charge value, the system controls the power battery to enter different working modes and controls the branch power battery to discharge according to the current working mode.

[0097] The auxiliary power supply mode of the power battery can be understood as a working mode that supplies power to non-drive auxiliary electrical equipment on the vehicle. For example, the auxiliary power supply mode of the power battery includes, but is not limited to, supplying power to onboard electrical appliances and air conditioning equipment. The driver display unit is configured with the auxiliary power supply mode of the power battery. This mode is activated to provide auxiliary power supply when the following conditions are met: the locomotive is static; the locomotive itself is the effective control end; the locomotive is not in a multiple-unit configuration; the 380V AC voltage contactor in the depot is not closed; the locomotive's running direction is "no direction"; at least one branch's corresponding charging / discharging unit is present; and the power battery and auxiliary control unit are both fault-free and without isolation.

[0098] The power battery auxiliary equipment test mode can be understood as a mode used to test whether the on-board auxiliary equipment is working properly. The locomotive activates the power battery auxiliary equipment test mode to realize the auxiliary equipment testing function in the depot, in order to detect the working status of the auxiliary load. For example, the power battery auxiliary equipment test mode includes, but is not limited to, testing whether auxiliary equipment such as inverters and water pumps are working properly, and the embodiments of the present invention do not limit this.

[0099] When the following conditions are met: the locomotive is static, the locomotive end is the effective control end, the locomotive is in a non-multi-unit state, the 380V AC voltage contactor in the depot is not closed, the locomotive's running direction is "no direction", at least one branch's corresponding charging / discharging unit, the power battery and auxiliary control unit are all fault-free and not isolated, the locomotive pantograph is lowered and the main circuit breaker is open, the three-phase automatic switch of the water pump corresponding to the normally operating auxiliary control unit is closed and there is no contactor closure fault, the necessary three-phase automatic switch is open and the power battery is not isolated, the power battery auxiliary machine test mode can be activated. If any condition is not met, entering this mode is not allowed.

[0100] The short-distance driving mode powered by the power battery can be understood as an emergency low-power drive mode. In this mode, the power battery system only outputs a small amount of electrical energy to the traction inverter, driving the vehicle to complete short-distance movement at low speed. The driver's display unit is set to the short-distance driving mode powered by the power battery. The locomotive activates this mode to achieve short-distance movement. The locomotive can achieve a maximum speed of 5 km / h when moving vehicles using the power battery. In this short-distance driving mode, electric braking is prohibited, and only air braking is used. Exemplary applications of the short-distance driving mode include, but are not limited to, towing the vehicle to a repair bay after a breakdown or moving it within a garage; this embodiment of the invention does not impose such limitations.

[0101] For a locomotive to enter the short-distance EMU mode powered by the power battery, the following conditions must be met: the locomotive is static; the locomotive end is the effective control end; the locomotive is in a non-multiple-unit state; the 380V AC voltage contactor in the depot is not closed; at least one branch has a corresponding charging / discharging unit; the power battery and auxiliary control unit are both fault-free and not isolated; the locomotive pantograph is lowered and the main circuit breaker is open; the three-phase automatic switch of the water pump corresponding to the normally functioning auxiliary control unit is closed and there is no contactor closure fault; the power battery is not isolated; the total air cylinder pressure is greater than 750 kPa; the main controller is in the "zero" position and the short-distance EMU axle motor is not isolated.

[0102] The load self-propelled mode can be understood as a working mode in which the power battery system outputs continuous low-power electrical energy to the traction inverter, driving the vehicle to move its own load at a speed lower than a preset speed value to complete a distance of several kilometers. For example, the load self-propelled mode includes, but is not limited to, low-speed shuttle services in scenic areas; this embodiment of the invention does not impose such limitations. The load self-propelled mode is set on the driver display unit, and the locomotive activates this mode to achieve last-mile vehicle movement. In the absence of external power supply, it can achieve single-unit short-distance self-propelled movement and meet the requirements of auxiliary machine testing functions.

[0103] When the following conditions are met: the locomotive is static, the locomotive end is the effective control end, the 380V AC voltage contactor in the depot is not closed, the locomotive pantograph is lowered and the main circuit breaker is open, the main controller is in the "zero" position, the protection interlock key is inserted, and at least one branch's corresponding charging / discharging unit, power battery, and auxiliary control unit are all fault-free and without isolation, the load self-propelled mode can be activated. When the branch power battery is in power battery auxiliary power supply mode, power battery auxiliary machine test mode, power battery short-distance moving vehicle mode, or load self-propelled mode, the branch power battery is controlled to exit the discharge mode and the power battery branch positive and negative contactors are disconnected to prevent unnecessary discharge and save power battery capacity.

[0104] Specifically, the no-power return mode can be understood as a working mode that requires maintaining the high-voltage circuit connection to ensure safety functions, while prohibiting the output of power to the drive system. When the locomotive is returning without power, to improve the comfort of the driver and passengers, the self-generating function during the no-power return ensures the locomotive load can operate, ensuring the normal operation of equipment such as cooling towers, traction fans, air conditioners, and lighting, and guaranteeing domestic power supply for a certain period under conditions of no-power return or no overhead contact line power. For example, the no-power return mode includes, but is not limited to, the working mode when the vehicle breaks down and needs to be towed; this embodiment of the invention does not impose such limitations.

[0105] For example, a locomotive unpowered return mode selection button is set on the driver display unit. When the locomotive is stationary, unpowered return can be activated. After exiting unpowered return, the speed needs to be reduced to zero before the mode can be activated again. The locomotive can manually exit the unpowered return mode at any time.

[0106] The no-power return mode is permitted to be activated when the following conditions are met: the locomotive is static, the locomotive end is the effective control end, the 380V AC voltage contactor in the depot is not closed, the locomotive is moving forward or backward, auxiliary control unit 1 or auxiliary control unit 2 is not isolated, the locomotive pantograph is lowered, and the main circuit breaker is open. The no-power return mode is permitted when at least one branch's corresponding charging / discharging unit, power battery, and auxiliary control unit are all fault-free and not isolated.

[0107] When multiple branch power batteries are in discharge mode and the state of charge of any one of the multiple branch power batteries is less than the preset charge value, and the branch power battery is in the no-power return mode, the multiple branch power batteries are controlled to not exit the branch power battery discharge mode, and the positive and negative contactors of the power battery branch remain closed, but the branch power battery does not discharge, ensuring the critical safety mode.

[0108] For example, when the charge value of branch A among the three working power battery branches is 18%, lower than the preset charge value of 20%, and the locomotive is in short-distance moving mode and wants to move at low speed, the power battery of branch A is controlled to exit the discharge mode, and all positive and negative contactors of the power battery branch are disconnected, preventing the vehicle from moving further and preventing over-discharge of the power battery of branch A. When the locomotive enters the no-power return mode due to a fault and needs to be towed, the power battery of branch A is controlled not to exit the discharge mode, and the positive and negative contactors of the power battery branch remain closed, but discharging to the drive system is prohibited, and power is only allowed to the braking system. During towing, the power battery is used to maintain the power supply of the safety system.

[0109] S603. When multiple branch power batteries are in discharge mode and the state of charge of any one of the multiple branch power batteries is greater than the preset charge value, and the branch power battery is in power battery auxiliary power supply mode, power battery auxiliary machine test mode, power battery short distance motor mode, load self-propelled mode or no power return mode, control the branch power battery to discharge.

[0110] Specifically, when multiple branch power batteries are in discharge mode, the state of charge of any one of the multiple branch power batteries is greater than the preset charge value, and the current working mode of the vehicle is power battery auxiliary power supply mode, power battery auxiliary machine test mode, power battery short distance vehicle mode, load self-propelled mode, or no power return mode, the branch power battery is controlled to discharge, allowing the power battery branch to output electrical energy to the load.

[0111] For example, when the locomotive speed reaches 30 km / h or higher, the power battery changes from a discharging state to a charging state, and corresponding auxiliary machines such as the cooling tower and traction fan are started. If the locomotive speed drops below 20 km / h, the auxiliary power supply can be restarted when conditions permit, and the power battery discharges to supply power to the air conditioner and inverter water pump.

[0112] S604. When multiple branch power batteries are in discharge mode and the state of charge of multiple branch power batteries is less than the preset charge value, and the branch power batteries are in power battery auxiliary power supply mode, power battery auxiliary machine test mode, power battery short distance vehicle mode or load self-propelled mode, control multiple branch power batteries to exit power battery auxiliary power supply mode, power battery auxiliary machine test mode, power battery short distance vehicle mode or load self-propelled mode, and do not allow branch power batteries that are not in power battery auxiliary power supply mode, power battery auxiliary machine test mode, power battery short distance vehicle mode or load self-propelled mode to enter the above modes.

[0113] Specifically, when multiple branch power batteries are in discharge mode and the state of charge of all working branch power batteries is less than the preset charge value, when the branch power batteries are in power battery auxiliary power supply mode, power battery auxiliary machine test mode, power battery short distance driving mode or load self-driving mode, the multiple branch power batteries are controlled not to enter the branch power battery discharge mode and not to enter the power battery auxiliary power supply mode, power battery auxiliary machine test mode, power battery short distance driving mode or load self-driving mode, and high power or unnecessary discharge is prohibited.

[0114] For example, when the state of charge of all branch power batteries is less than the preset charge value, if the driver wants to turn on the air conditioner (auxiliary power supply mode), the maintenance personnel want to test the inverter (auxiliary machine test mode), or the vehicle wants to move at low speed after a malfunction (short distance vehicle mode), the control system will prevent the branch power batteries from entering the discharge mode, the air conditioner cannot be started, the test cannot be carried out, and the vehicle cannot be driven.

[0115] S605. When multiple branch power batteries are in a discharging state and the state of charge of multiple branch power batteries is less than the preset charge value, and the branch power batteries are in a no-power return mode, control multiple branch power batteries to enter the branch power battery discharge mode without exiting the branch power battery discharge mode and allow branch power batteries that are not in the no-power return mode to enter the no-power return mode.

[0116] Specifically, when multiple branch power batteries are in a discharging state and the state of charge of multiple branch power batteries is less than the preset charge value, and the branch power batteries are in a no-power return mode, the system controls multiple branch power batteries to enter the branch power battery discharge mode, allowing them to supply power to safety-related systems and ensuring the safety of the return process.

[0117] For example, when the state of charge of all branch batteries is less than the preset charge value, in the event of a vehicle malfunction requiring towing (no-power return mode), the control system allows the branch batteries to enter discharge mode. During towing, the vehicle's braking and steering systems operate normally, ensuring towing safety. It should be noted that the names of operating modes with lower output power, such as power battery auxiliary power supply mode, power battery auxiliary machine test mode, or power battery short-distance vehicle driving mode, and operating modes with higher output power, such as power battery no-power return mode and power battery load self-propelled mode, may vary depending on actual needs. This embodiment of the invention does not impose any limitations on these differences.

[0118] The embodiments of this invention employ the above technical solution, dynamically adjusting the discharge of the power battery based on the state of charge and operating mode of the power batteries in multiple working power battery branches during discharge. This achieves adaptive adjustment of power battery charging and discharging, extending power battery life while ensuring driving safety. It also avoids unnecessary over-discharge caused by low power battery charge, thus solving the problem of excessive power battery consumption.

[0119] Figure 7 This is a flowchart of the seventh multi-branch control method for power batteries provided in this embodiment of the invention. This embodiment describes in detail one of the methods in the above embodiments for controlling the working state of branch power batteries based on the power battery capacity and the charging and discharging state of multiple branch power batteries. Figure 7 As shown, the method specifically includes:

[0120] S701. When it is determined that multiple power battery branches are fault-free and not isolated, determine at least one of the following: voltage difference of power batteries in different branches within the same battery system, state of charge of multiple power batteries, and battery capacity of multiple power batteries.

[0121] S702. When the battery capacity is less than the preset capacity, control the branch power battery to enter at least one of the following modes: power battery auxiliary power supply mode, power battery auxiliary machine test mode, or power battery short-distance vehicle mode.

[0122] Specifically, when the rated capacity of the power battery is low or its capacity has severely degraded due to aging, resulting in a capacity less than the preset capacity and unable to support high-power loads operating simultaneously, the control branch power battery will enter at least one of the following modes: a power battery auxiliary power supply mode with lower output power, a power battery auxiliary machine test mode, or a power battery short-distance vehicle mode, prohibiting the operation of high-power operating modes. Based on the current operating mode and actual application scenario, only the necessary operating equipment matching the current operating mode will be closed, while non-essential equipment will be disconnected. Then, the equipment will be started sequentially according to its starting power, from lowest to highest. When equipped with a large-capacity power battery, the power battery can achieve functions required for special application scenarios such as phase-splitting auxiliary traction and emergency traction, and the traction capacity is designed to match the power battery.

[0123] Optionally, when it is determined that at least one power battery branch has a fault or is isolated, the power battery of the fault-free and non-isolated branch is controlled to enter at least one of the following modes: power battery auxiliary power supply mode, power battery auxiliary machine test mode, or power battery short-distance vehicle mode.

[0124] Specifically, when multiple power battery branches are faulty or isolated, and only a few power battery branches are functioning normally and cannot withstand the simultaneous startup of multiple devices, the power battery in the fault-free and unisolated branches should be controlled to enter at least one of the following modes: a power battery auxiliary power supply mode with lower output power, a power battery auxiliary machine test mode, or a power battery short-distance vehicle mode. High-power operation should be prohibited. Based on the current operating mode and the actual application scenario, only the necessary operating devices matching the current operating mode should be closed, while non-essential devices should be disconnected. Then, the devices should be started sequentially according to their startup power, from lowest to highest.

[0125] For example, when the battery capacity is less than the preset capacity or multiple power battery branches are faulty or isolated, the circuit breaker of the water pump corresponding to the working power battery branch and the basic facilities for domestic power supply in the driver's cab are closed to ensure normal domestic power supply. Then, based on the equipment starting power of the composite cooling fan and the main compressor, when the cooling water temperature or motor temperature exceeds the set value, and when the total air cylinder pressure is lower than the set value, the corresponding composite cooling fan and the main compressor are started in turn in a timed manner.

[0126] This invention employs the above technical solution. When the battery capacity is less than the preset capacity, or when at least one power battery branch is faulty or isolated, the power battery of the branch is controlled to enter a power battery auxiliary power supply mode, a power battery auxiliary machine test mode, or a power battery short-distance vehicle mode according to the actual application scenario. Based on the output power of the equipment, the necessary equipment for the current application scenario is started in a time-sharing manner to ensure the locomotive's domestic power supply for a certain period under conditions of no-fire return or no overhead contact line power, avoiding the locomotive paralysis caused by prohibiting all outputs. By using low-power mode and selective equipment startup, the total load is controlled when the power battery output capacity is limited, protecting the power battery's lifespan and achieving a balance between functional availability and battery safety.

[0127] Figure 8 This is a flowchart of the eighth power battery multi-branch control method provided in this embodiment of the invention. This embodiment provides another power battery multi-branch control method based on the above-mentioned optional implementation methods. For example... Figure 8 As shown, the method specifically includes:

[0128] S801. When it is determined that at least one power battery branch has a fault or is isolated, control all powered charging and discharging units and power battery branches to power off in sequence.

[0129] Specifically, when multiple power battery branches are working normally, if at least one power battery branch is faulty or isolated, the simultaneous operation of multiple branches will switch to single-branch operation. Regardless of whether the current condition is charging or discharging, the charging and discharging unit working contactor and the branch positive and negative contactor must be disconnected in sequence to control the charging and discharging unit to stop charging and discharging and control all powered power battery branches to be de-energized.

[0130] The isolation triggers include, but are not limited to, automatic isolation and manual isolation, and the embodiments of the present invention do not impose any restrictions on them.

[0131] S802, sequentially control the power battery branch and charging / discharging unit where the fault-free and non-isolated branch power battery is located to be powered on.

[0132] Specifically, after confirming that the charging and discharging unit working contactor and the branch positive and negative contactor are completely disconnected, the branch positive and negative contactors of the faultless and non-isolated power battery branch and the charging and discharging unit working contactor are closed in sequence to control the power battery branch where the faultless and non-isolated power battery is located to be powered on and resume operation.

[0133] For example, in a battery system with branches A, B, and C discharging in parallel, if branch B and C suddenly experience overcurrent faults, triggering automatic isolation, the system switches to a state where only branch A is operating normally. The system detects that branch B and C are isolated, and only branch A is operating normally. It disconnects the charging / discharging unit's contactor, stopping the charging / discharging unit from discharging. Then, it sequentially disconnects the positive and negative contactors for branches A, B, and C, de-energizing them. After confirming all contactors are completely disconnected, it closes the positive and negative contactors for the normally operating branch A, and then closes the charging / discharging unit's contactor. Branch A then discharges alone to supply power to the system, and the vehicle continues to operate.

[0134] This invention employs the above technical solution. When at least one power battery branch is determined to be faulty or isolated, all energized power battery branches are de-energized, and then the power battery branch containing the fault-free and unisolated branch is energized. By first completely de-energizing and disconnecting all contactors, and then sequentially re-closing them, a safe transition from multi-branch operation to single-branch operation is achieved when a branch fault occurs. This prevents the high voltage or fault signal from the faulty branch from being transmitted to the normal branch, thus avoiding the escalation of the fault. Simultaneously, it avoids directly disconnecting the contactor of the faulty branch, which could cause a sudden increase in current in the normal branch and lead to overcurrent damage, ensuring the smoothness and safety of the branch transition.

[0135] Based on the same inventive concept, embodiments of the present invention also provide a power battery multi-branch control system, which can implement the power battery multi-branch control method provided in any of the above optional embodiments. Figure 9 This is a schematic diagram of a multi-branch control system for a power battery provided in an embodiment of the present invention, as shown below. Figure 9 As shown, the multi-branch control system structure of the power battery includes: a control module 1, at least one single-group battery system 200, and at least one charging / discharging unit 100. The single-group battery system 200 includes at least one power battery branch 2. The charging / discharging unit 100 includes a charging / discharging unit working contactor 10, and the power battery branch 2 includes a branch positive and negative contactor 20. The control module 1 is communicatively connected to the charging / discharging unit working contactor 10 and the branch positive and negative contactor 2. When it is determined that multiple power battery branches 2 are fault-free and without isolation, the control module 1 determines at least one of the following: the voltage difference of the power batteries in different branches within the same group of battery systems, the state of charge of multiple branches of power batteries, and the battery capacity of multiple branches of power batteries. Within the same group of battery systems, the control module 1 controls the working state of the branch power batteries according to the correspondence between multiple voltage differences and preset differences, the state of charge and the battery capacity, and the charging / discharging state of multiple branches of power batteries.

[0136] In this embodiment, the multi-branch control system structure for the power battery includes a control module 1, at least one single-cell battery system 200, and at least one charging / discharging unit 100. The control module 1 can be understood as an integrated unit that realizes multi-branch charging / discharging control, state monitoring, fault diagnosis, and mode switching of the power battery system. The single-cell battery system 200 can be understood as an independent energy storage and power conversion unit composed of one or more power battery branches 20, matching contactor assemblies, and sensor assemblies. The charging / discharging unit 100 can be understood as a unit responsible for bidirectional power conversion and overall circuit on / off control, capable of receiving power during charging and outputting power during discharging according to the instructions of the control module. The charging / discharging unit 100 includes a charging / discharging unit working contactor 10 for controlling the on / off state of the charging / discharging unit 100. The single-cell battery system 200 includes at least one power battery branch 20. The power battery branch 20 can be understood as a minimum energy storage and power output unit composed of multiple individual cells connected in series or parallel within a single battery system 200. It is equipped with independent branch positive and negative contactors 2 and can be independently connected to the main circuit of the system. The power battery branch 20 includes branch positive and negative contactors 2, which are used to control the closing and opening of the power battery branch.

[0137] Specifically, control module 1 is communicatively connected to the control module of charging / discharging unit 100 and the control module of the power battery. It is used to determine at least one of the following when multiple power battery branches 20 are fault-free and without isolation: the voltage difference between different branches of the power battery within the same battery group system; the state of charge (SOC) of the multiple branches of the power battery; and the battery capacity of the multiple branches of the power battery. The voltage difference between different branches of the power battery within the same battery group system can be understood as the voltage difference between any two power battery branches within the same battery group system. The SOC of the multiple branches of the power battery can be understood as the percentage of the remaining usable capacity of the power battery at a certain moment compared to its rated capacity under the same conditions, reflecting the current remaining charge level of the battery. The battery capacity of the power battery can be understood as the total amount of charge that the power battery can release under specified charging and discharging conditions, and can be used to measure the energy storage capacity of the power battery.

[0138] Control module 1 compares the voltage differences between different branches of the power batteries within the same battery group with a preset difference value to determine whether the voltage difference exceeds the preset difference value, and controls the power-on sequence of the power battery branches according to the charging and discharging state of the power batteries. Control module 1 sets a working threshold for the state of charge (SOC) of the power batteries and monitors whether the SOC of the operating power batteries is below the threshold, controlling the operating state of the branch power batteries according to their charging and discharging states. Control module 1 also controls the power batteries to enter different operating modes based on their capacity and the current application scenario.

[0139] The multi-branch control system for power batteries provided by this invention comprises a control module 1, at least one single-cell battery system 200, and at least one charge / discharge unit 100 including a discharge unit working contactor 10. Each single-cell battery system 200 includes at least one power battery branch 20 including branch positive and negative contactors 2. The control module 1 is communicatively connected to the control module of the charge / discharge unit 100 and the control module of the power battery. When it is determined that multiple power battery branches 20 are fault-free and without isolation, the control module determines at least one of the following: voltage difference between different branches of the power batteries within the same battery system, state of charge of multiple branches of the power batteries, and battery capacity of multiple branches of the power batteries. Based on the correspondence between multiple voltage differences and preset differences, at least one of state of charge and battery capacity, and the charge / discharge state of multiple branches of the power batteries, the control module controls the operating state of the branch power batteries. By implementing differentiated control of multiple branches of the power battery in a single battery system, precise isolation of faulty branches in the event of a single or multiple branch failure is achieved, ensuring stable operation of normal branches without circulating current. Simultaneously, control logic is tailored to the power battery capacity and actual needs, meeting the requirements of power battery applications in various scenarios. This solves the problem of sacrificing power for safety protection during single or multiple branch failures, resulting in wasted power source resources and the inability to dynamically control power battery branches according to actual operating requirements.

[0140] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A multi-branch control method for a power battery, characterized in that, include: When it is determined that multiple power battery branches are fault-free and not isolated, at least one of the following is determined: the voltage difference of power batteries in different branches within the same battery system, the state of charge of multiple power batteries in multiple branches, and the battery capacity of multiple power batteries in multiple branches. Within the same battery system, the operating state of the branch power battery is controlled based on at least one of the correspondence between multiple voltage differences and preset differences, the state of charge and the battery capacity, and the charging and discharging states of multiple branch power batteries.

2. The multi-branch control method for a power battery according to claim 1, characterized in that, The operating state of the branch power battery is controlled based on at least one of the correspondence between multiple voltage differences and preset differences, the state of charge, and the battery capacity, as well as the charge and discharge states of multiple branch power batteries, including: When multiple voltage differences are greater than the preset difference and the branch power battery is discharging, the power battery branch containing the power battery with the largest voltage value among the multiple branch power batteries is closed. Among the multiple unclosed power battery branches corresponding to the multiple power batteries in the branch circuits, the multiple power battery branches corresponding to the multiple power batteries with voltage differences less than the preset difference are closed in sequence according to the increasing voltage difference between them and the power battery in the branch circuit with the largest voltage value.

3. The multi-branch control method for a power battery according to claim 1, characterized in that, The operating state of the branch power battery is controlled based on at least one of the correspondence between multiple voltage differences and preset differences, the state of charge, and the battery capacity, as well as the charge and discharge states of multiple branch power batteries, including: When multiple voltage differences are greater than the preset difference and the branch power battery is charging, close the power battery branch containing the power battery with the smallest voltage among the multiple branch power batteries; Among the multiple unclosed power battery branches corresponding to the multiple power batteries in the branch power batteries, the multiple power battery branches corresponding to the multiple power batteries with voltage differences less than the preset difference are closed in order of decreasing voltage difference with the power battery in the branch power battery with the smallest voltage value.

4. The multi-branch control method for a power battery according to claim 1, characterized in that, The operating state of the branch power battery is controlled based on at least one of the correspondence between multiple voltage differences and preset differences, the state of charge, and the battery capacity, as well as the charge and discharge states of multiple branch power batteries, including: When multiple voltage differences are all less than the preset difference and the number of power-on branches increases, all the already powered-on charging and discharging units and power-on branches are sequentially powered off. The power battery branch and the charging / discharging unit, which are fault-free and not isolated, are powered on sequentially.

5. The multi-branch control method for a power battery according to claim 4, characterized in that, After controlling the power supply to at least two of the aforementioned battery branches according to demand, the method further includes: Set a current sharing period, and control the current of one of the power battery branches to be a first current and the current of the other power battery branch to be a second current during the current sharing period; the first current is greater than zero and the second current is less than zero. During the current sharing period, overcurrent faults in any two power battery branches are filtered out.

6. The multi-branch control method for a power battery according to claim 1, characterized in that, The operating state of the branch power battery is controlled based on at least one of the correspondence between multiple voltage differences and preset differences, the state of charge, and the battery capacity, as well as the charge and discharge states of multiple branch power batteries, including: When multiple branch power batteries are in discharge mode and the state of charge of any one of the branch power batteries is less than a preset value, and the branch power battery is in power battery auxiliary power supply mode, power battery auxiliary machine test mode, power battery short distance motor mode, load self-propelled mode, or no-power return mode, all the charged and discharged units and the power battery branches that have been powered on are sequentially powered off. Then, the power battery branches and the charged and discharged units that are in power battery auxiliary power supply mode, power battery auxiliary machine test mode, power battery short distance motor mode, load self-propelled mode, or no-power return mode and whose state of charge of the branch power battery is greater than the preset value are sequentially powered on. When multiple branch power batteries are in discharge mode and the state of charge of any one of the multiple branch power batteries is greater than the preset charge value, and the branch power battery is in the power battery auxiliary power supply mode, the power battery auxiliary machine test mode, the power battery short distance motor mode, the load self-propelled mode or the no-power return mode, the branch power battery is controlled to discharge. When multiple branch power batteries are in discharge mode and the state of charge of multiple branch power batteries is less than the preset charge value, and the branch power batteries are in power battery auxiliary power supply mode, power battery auxiliary machine test mode, power battery short-distance vehicle mode or load self-propelled mode, the system controls multiple branch power batteries to exit the power battery auxiliary power supply mode, the power battery auxiliary machine test mode, the power battery short-distance vehicle mode or the load self-propelled mode, and does not allow branch power batteries that are not in the power battery auxiliary power supply mode, the power battery auxiliary machine test mode, the power battery short-distance vehicle mode or the load self-propelled mode to enter the above modes; When multiple branch power batteries are in a discharging state and the state of charge of multiple branch power batteries is less than the preset charge value, and the branch power batteries are in a no-power return mode, the system controls multiple branch power batteries not to exit the branch power battery discharge mode and allows branch power batteries that are not in the no-power return mode to enter the no-power return mode.

7. The multi-branch control method for a power battery according to claim 1, characterized in that, The operating state of the branch power battery is controlled based on at least one of the correspondence between multiple voltage differences and preset differences, the state of charge, and the battery capacity, as well as the charge and discharge states of multiple branch power batteries, including: When the battery capacity is less than the preset capacity, the branch power battery is controlled to enter at least one of the following modes: power battery auxiliary power supply mode, power battery auxiliary machine test mode, or power battery short-distance vehicle mode.

8. The multi-branch control method for a power battery according to claim 1, characterized in that, The multi-branch control method for power batteries also includes: When it is determined that at least one of the power battery branches is faulty or isolated, the power battery of the fault-free and unisolated branch is controlled to enter at least one of the power battery auxiliary power supply mode, power battery auxiliary machine test mode, or power battery short-distance vehicle mode.

9. The multi-branch control method for a power battery according to claim 1, characterized in that, The multi-branch control method for power batteries also includes: When it is determined that at least one of the power battery branches is faulty or isolated, all the charging and discharging units and the power battery branches that have been powered on are sequentially powered off. The power battery branch containing the fault-free and non-isolated branch power battery and the charging and discharging unit are powered on sequentially.

10. A multi-branch control system for a power battery, characterized in that, include: The system includes a control module, at least one single-cell battery system, and at least one charging / discharging unit, wherein the single-cell battery system includes at least one power battery branch. The charging and discharging unit includes a charging and discharging unit working contactor, and the power battery branch includes a branch positive and negative contactor. The control module is communicatively connected to the charging / discharging unit working contactor and the branch positive and negative contactors. The control module is used to determine at least one of the following when it is determined that multiple power battery branches are fault-free and unisolated: the voltage difference between different branches of the power battery in the same battery group system, the state of charge of multiple branches of the power battery, and the battery capacity of multiple branches of the power battery. Within the same battery group system, the control module controls the working state of the branch power battery according to the correspondence between multiple voltage differences and preset differences, at least one of the state of charge and the battery capacity, and the charging / discharging state of multiple branches of the power battery.

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