Method, device and system for controlling energy storage system

Abstract

The invention provides a method, device and system for controlling an energy storage system. The energy storage system comprises N battery clusters which are connected in parallel, N is a positive integer larger than 1, and the method comprises the steps that the current of at least one battery cluster in the N battery clusters is obtained; under the condition that the energy storage system is in a standing state, the overcurrent level of the energy storage system is determined according to the current of a first battery cluster in the at least one battery cluster, and the first battery cluster is the battery cluster with the largest current in the at least one battery cluster; and controlling the energy storage system according to the overcurrent level. According to the method, the device and the system provided by the embodiment of the invention, the inconsistency between different battery clusters in the energy storage system can be reduced.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of batteries, and more specifically, to a method, device, and system for controlling an energy storage system. Background Art

[0002] Regarding the inter-cluster circulating current phenomenon in the energy storage system, the current mainstream solution is how to prevent the occurrence of the circulating current phenomenon, and there is no solution for how to optimize the treatment after the circulating current appears in the energy storage system. Summary of the Invention

[0003] The embodiments of the present application provide a method, device, and system for controlling an energy storage system, which helps to reduce the inconsistency between different battery clusters in the energy storage system.

[0004] In a first aspect, a method for controlling an energy storage system is provided. The energy storage system includes N battery clusters connected in parallel, where N is a positive integer greater than 1. The method includes: obtaining the current of at least one battery cluster among the N battery clusters; when the energy storage system is in a stationary state, determining the overcurrent level of the energy storage system according to the current of the first battery cluster among the at least one battery cluster, where the first battery cluster is the battery cluster with the largest current among the at least one battery cluster; and controlling the energy storage system according to the overcurrent level.

[0005] In this embodiment, when the energy storage system is in a stationary state, the BMS determines the overcurrent level of the energy storage system according to the largest current among the at least one battery cluster, and controls the energy storage system based on the overcurrent level. For example, different control strategies can be adopted for different overcurrent levels, which is beneficial to reducing the inconsistency between battery clusters, further beneficial to reducing the potential risks of uneven current or overcurrent caused by SOC inconsistency in the energy storage system, and at the same time beneficial to solving the problems of inconsistent battery aging rates or reduced available battery power caused by SOC inconsistency.

[0006] In a possible implementation, determining the overcurrent level of the energy storage system according to the current of the first battery cluster among the at least one battery cluster includes: when the current of the first battery cluster is greater than the first threshold and less than the second threshold, determining that the energy storage system has a first-level overcurrent fault; or, when the current of the first battery cluster is not less than the second threshold and the fault parameter is less than the third threshold, determining that the energy storage system has a second-level overcurrent fault, where the fault parameter is used to indicate the number of overcurrent faults above the first level that occur in the energy storage system; or, when the current of the first battery cluster is not less than the second threshold and the fault parameter is not less than the third threshold, determining that the energy storage system has a third-level overcurrent fault.

[0007] In this embodiment, based on the magnitude of the current in the battery cluster with the largest current among at least one battery cluster and the magnitude of the fault parameter, the overcurrent levels of the energy storage system are at least divided into three levels. According to different overcurrent levels, different control strategies can be implemented for the energy storage system, which is beneficial to adjusting the SOC between each battery cluster of the energy storage system to a balanced state to the greatest extent without increasing costs, and improving the overall lifespan of the energy storage system.

[0008] In a possible implementation manner, controlling the energy storage system according to the overcurrent level includes: when a second-level overcurrent fault occurs in the energy storage system, reducing the charging rate of the energy storage system for the next charge; or when a second-level overcurrent fault occurs in the energy storage system, reducing the discharging rate of the energy storage system for the next discharge.

[0009] In this embodiment, when a second-level overcurrent fault occurs in the energy storage system, the energy storage system can be charged or discharged at a reduced rate during the next charge or discharge. By adjusting this strategy, the inconsistency between each battery cluster in the energy storage system can be effectively alleviated at the end of charge or discharge, and the SOC difference between each battery cluster can be reduced.

[0010] In a possible implementation manner, controlling the energy storage system according to the overcurrent level includes: when a third-level overcurrent fault occurs in the energy storage system, cutting off the main circuit relay of the energy storage system to adjust the abnormal battery cluster in the energy storage system.

[0011] In this embodiment, once it is determined that a third-level overcurrent fault has occurred in the energy storage system, the BMS can control the main circuit relay of the energy storage system to disconnect, and then the abnormal battery cluster in the energy storage system can be found. And according to the difference from the DC resistance of other battery clusters, the electrical box in the abnormal battery cluster can be replaced, so that the DC resistance of the abnormal battery cluster is adjusted to the same level as that of other battery clusters.

[0012] In a possible implementation manner, the method further includes: when an overcurrent fault above the first level occurs in the energy storage system, storing the identifier of the first battery cluster, and the identifier is used to determine the abnormal battery cluster.

[0013] In this embodiment, when an overcurrent fault above the first level occurs in the energy storage system, the identifier of the first battery cluster is stored, so that once it is determined that a third-level overcurrent fault has occurred in the energy storage system, the BMS can quickly lock the abnormal battery cluster.

[0014] In a possible implementation manner, the method further includes: sending a first instruction to the energy management system, and the first instruction is used to indicate the overcurrent level of the energy storage system.

[0015] In this embodiment, when a circulation occurs in the energy storage system, the BMS sends a first instruction indicating the overcurrent level of the energy storage system to the EMS, which helps the EMS to adjust the control strategy of the energy storage system in a timely manner according to the current overcurrent situation of the energy storage system, thereby improving the balance between the various battery clusters in the energy storage system.

[0016] In one possible implementation, when the energy storage system is in a static state, the overcurrent level of the energy storage system is determined based on the current of a first battery cluster in at least one battery cluster, including: when the energy storage system is in a static state, determining whether there is a battery cluster in at least one battery cluster whose current is greater than a first threshold; when it is determined that there is a battery cluster in at least one battery cluster whose current is greater than the first threshold, determining the overcurrent level of the energy storage system based on the current of the first battery cluster.

[0017] In this embodiment, when the energy storage system is in a static state, it can be determined first whether there is a battery cluster in at least one battery cluster whose current is greater than a first threshold value. Only when there is a battery cluster whose current is greater than the first threshold value, the overcurrent level of the energy storage system is further determined based on the current of the first battery cluster. Compared with the solution of directly classifying the overcurrent of the energy storage system based on the current of the first battery cluster, the amount of calculation of the BMS is reduced when there is no circulating current in the energy storage system.

[0018] In one possible implementation, when the energy storage system is in a static state, determining whether there is a battery cluster in at least one battery cluster whose current is greater than a first threshold includes: when the energy storage system is in a static state, determining whether the current of a first battery cluster is greater than the first threshold.

[0019] In this embodiment, as long as it is determined that the current of the battery cluster with the largest current in at least one battery cluster is greater than the first threshold, it can be considered that a circulating current has occurred in the energy storage system, which is conducive to overcurrent classification of the energy storage system before a safety risk is generated, and the energy storage system is controlled based on the overcurrent classification, thereby reducing the probability of uneven current or overcurrent in the energy storage system due to inconsistency of battery parameters in the energy storage system.

[0020] In a possible implementation, the method further includes: when the allowable current of the energy storage system is equal to 0, determining that the energy storage system is in a static state.

[0021] In a second aspect, a device for controlling an energy storage system is provided. The energy storage system includes N battery clusters connected in parallel, where N is a positive integer greater than 1. The device includes: an acquisition unit configured to acquire the current of at least one battery cluster among the N battery clusters; a determination unit configured to determine the overcurrent level of the energy storage system according to the current of a first battery cluster among the at least one battery cluster when the energy storage system is in a stationary state, where the first battery cluster is the battery cluster with the largest current among the at least one battery cluster; and a control unit configured to control the energy storage system according to the overcurrent level.

[0022] In a possible implementation, the determination unit is specifically configured to: determine that a first-level overcurrent fault has occurred in the energy storage system when the current of the first battery cluster is greater than a first threshold and less than a second threshold; or, determine that a second-level overcurrent fault has occurred in the energy storage system when the current of the first battery cluster is not less than the second threshold and the fault parameter is less than a third threshold, where the fault parameter is used to indicate the number of overcurrent faults above the first level that have occurred in the energy storage system; or, determine that a third-level overcurrent fault has occurred in the energy storage system when the current of the first battery cluster is not less than the second threshold and the fault parameter is not less than the third threshold.

[0023] In a possible implementation, the control unit is specifically configured to: reduce the charging rate of the energy storage system in the case of a second-level overcurrent fault occurring in the energy storage system for the next charging of the energy storage system; or reduce the discharging rate of the energy storage system in the case of a second-level overcurrent fault occurring in the energy storage system for the next discharging of the energy storage system.

[0024] In a possible implementation, the control unit is specifically configured to: cut off the main circuit relay of the energy storage system in the case of a third-level overcurrent fault occurring in the energy storage system to adjust the abnormal battery cluster in the energy storage system.

[0025] In a possible implementation, the device further includes: a storage unit configured to store the identifier of the first battery cluster in the case of a third-level overcurrent fault occurring in the energy storage system, where the identifier is used to determine the abnormal battery cluster.

[0026] In a possible implementation, the device further includes: a sending unit configured to send a first instruction to an energy management system, where the first instruction is used to indicate the overcurrent level of the energy storage system.

[0027] In a possible implementation, the determination unit is specifically configured to: determine whether there is a battery cluster among the at least one battery cluster whose current is greater than the first threshold when the energy storage system is in a stationary state; and determine the overcurrent level of the energy storage system according to the current of the first battery cluster in the case of determining that there is a battery cluster among the at least one battery cluster whose current is greater than the first threshold.

[0028] In a possible implementation, the determining unit is specifically configured to: determine whether the current of the first battery cluster is greater than a first threshold when the energy storage system is in a stationary state.

[0029] In a possible implementation, the determining unit is further configured to: determine that the energy storage system is in a stationary state when the allowable current of the energy storage system is equal to 0.

[0030] In a third aspect, a system for controlling an energy storage system is provided, including a memory and a processor. The memory is used to store instructions, and the processor is used to read the instructions and execute the method in the first aspect and any possible implementation manner of the first aspect according to the instructions.

[0031] In a fourth aspect, a chip is provided, including a processor, which is used to call and run a computer program from a memory, so that a device installed with the chip executes the method in the first aspect and any possible implementation manner of the first aspect.

[0032] In a fifth aspect, a computer program is provided, which enables a computer to execute the method in the first aspect and any possible implementation manner of the first aspect.

[0033] In a sixth aspect, a computer-readable storage medium is provided, which is used to store a computer program, and the computer program enables a computer to execute the method in the first aspect and any possible implementation manner of the first aspect.

[0034] In a seventh aspect, a computer program product is provided, including computer program instructions, and the computer program instructions enable a computer to execute the method in the first aspect and any possible implementation manner of the first aspect. Description of the Drawings

[0035] To more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained according to the drawings without creative efforts.

[0036] Figure 1 is a schematic block diagram of an energy storage system provided by an embodiment of the present application.

[0037] Figure 2 is a first schematic block diagram of a method for controlling an energy storage system provided by an embodiment of the present application.

[0038] Figure 3 is a second schematic block diagram of a method for controlling an energy storage system provided by an embodiment of the present application.

[0039] Figure 4 It is the third schematic block diagram of the method for controlling an energy storage system provided by an embodiment of the present application.

[0040] Figure 5 It is the fourth schematic block diagram of the method for controlling an energy storage system provided by an embodiment of the present application.

[0041] Figure 6 It is a schematic flowchart of the method for controlling an energy storage system provided by an embodiment of the present application.

[0042] Figure 7 It is a schematic block diagram of the device for controlling an energy storage system provided by an embodiment of the present application.

[0043] Figure 8 It is another schematic block diagram of the device for controlling an energy storage system provided by an embodiment of the present application.

[0044] Figure 9 It is a schematic block diagram of the system for controlling an energy storage system provided by an embodiment of the present application. Detailed implementation manners

[0045] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0046] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by those skilled in the technical field to which the present application belongs; the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the specification and claims of the present application or the above drawings are used to distinguish different objects and are not used to describe a specific order or primary-secondary relationship.

[0047] Referring to "embodiment" in the present application means that a specific feature, structure or characteristic described in combination with the embodiment may be included in at least one embodiment of the present application. The appearance of this phrase at various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described in the present application can be combined with other embodiments.

[0048] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "connected" and "coupled" can be directly connected or indirectly connected through an intermediate medium, and can be the internal communication of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0049] In the present application, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in the present application generally represents an "or" relationship between the front and rear associated objects.

[0050] The battery cluster in the present application refers to a battery combination in which batteries are connected in series, parallel, or a combination of series and parallel. Among them, the combination of series and parallel means a mixture of series and parallel. For example, the battery cluster in the present application can be formed by connecting multiple batteries in series or parallel. For another example, the battery cluster in the present application can be formed by first connecting multiple batteries in parallel and then in series. A battery refers to a single physical module including one or more battery cells to provide a higher voltage and capacity. For example, a battery can be a battery module or a battery pack. For another example, a battery can be an electrical box or an electrical cabinet, where the electrical box can be formed by connecting multiple battery cells in series and / or parallel, and the electrical cabinet can be formed by connecting multiple electrical boxes in series and / or parallel.

[0051] It should be understood that the battery in the embodiments of the present application can be a lithium-ion battery, a lithium metal battery, a lead-acid battery, a nickel-cadmium battery, a nickel-metal hydride battery, a lithium-sulfur battery, a lithium-air battery, or a sodium-ion battery, etc., which is not limited herein.

[0052] Currently, in most energy storage systems, it is necessary to connect battery clusters in parallel to increase the system capacity. Due to the inconsistency of the state of charge (SOC) between battery clusters, there is a large difference in the terminal voltage between the clusters. When there is a pressure difference between the battery clusters, a circulating current phenomenon between the clusters will occur after charging and discharging, that is, the battery cluster with a higher terminal voltage charges the battery cluster with a lower terminal voltage. After the circulating current appears in the energy storage system, it represents that the battery states and parameters between different clusters are inconsistent, and this inconsistency will increase the hidden danger of uneven current or overcurrent during the operation of the energy storage system. Therefore, it is necessary to perform intelligent management and control on the energy storage system after the circulating current appears to reduce the inconsistency between different battery clusters.

[0053] In view of this, an embodiment of the present application provides a method for controlling an energy storage system. When the energy storage system is in a stationary state, by monitoring the current of at least one battery cluster in the energy storage system and determining the overcurrent level of the energy storage system based on the current of the battery cluster with the largest current among the at least one battery cluster, and controlling the energy storage system based on the overcurrent level of the energy storage system, it helps to reduce the inconsistency between different battery clusters in the energy storage system.

[0054] Figure 1 FIG. 4 shows a schematic block diagram of an energy storage system 100 provided by an embodiment of the present application.

[0055] As Figure 1 shown, the energy storage system 100 includes: N battery clusters 110, an adjustment switch module (for example, including the adjustment switch 130 shown in Figure 1 ) and at least one variable voltage module 120. Wherein, N is a positive integer greater than 1. The N battery clusters 110 are connected in parallel with each other, and each battery cluster 110 among the N battery clusters 110 is connected in series with one variable voltage module 120 among the at least one variable voltage module 120 through one adjustment switch 130 in the adjustment switch module. The at least one variable voltage module 120 and the adjustment switch module are used to adjust the electrical parameters of the N battery clusters 110 so that the electrical parameters of the N battery clusters 110 reach equilibrium.

[0056] Specifically, each battery cluster 110 among the N battery clusters 110 may include at least one battery, and the at least one battery may be connected in series or in series-parallel with each other. After each variable voltage module 120 among the at least one variable voltage module 120 is connected in series with a battery cluster 110 through an adjustment switch 130, it can adjust the current of the battery cluster 110, and further adjust other electrical parameters such as the voltage of the battery cluster 110.

[0057] Optionally, in order to manage and maintain the energy storage system intelligently and prevent safety problems in the energy storage system, a battery management system (BMS) is generally also provided in the energy storage system 100 for monitoring the status of each battery cluster. For example, the BMS can monitor parameters such as the current, voltage, temperature of each battery cluster, and the voltage of the battery cells in each battery cluster.

[0058] In some embodiments, Figure 1 the adjustment switch module shown in Figure 1 in addition to including the adjustment switch 130 connected in series with each battery cluster shown in

[0059] By way of example and not limitation, the variable voltage module 120 may be a direct current / direct current (DC / DC) converter, an alternating current / direct current (AC / DC) converter, a variable resistor, or the like. Optionally, the variable voltage module 120 may include at least one DC / DC converter, or the variable voltage module 120 may include both an AC / DC converter and a DC / DC converter, or the like, at the same time.

[0060] Optionally, as Figure 1 shown, the regulating switch module may include N regulating switches 130, and the N regulating switches 130 correspond to N battery clusters 110 one by one. Optionally, in addition to the N regulating switches 130, the regulating switch module may further include other components for assisting the user to regulate the switches 130, such as capacitors, resistors, etc. The specific structure of the regulating switch module in the embodiments of the present application is not limited. In addition, the switches in the regulating switch module include but are not limited to switch structures such as relays, and the specific types of the switches are also not limited in the embodiments of the present application.

[0061] Figure 2 A schematic block diagram of a method 200 for controlling an energy storage system provided by an embodiment of the present application is shown. Optionally, the energy storage system may be Figure 1 the energy storage system 100 shown, that is, the energy storage system includes N battery clusters connected in parallel, where N is a positive integer greater than 1. The method 200 may be executed by a battery management system in the energy storage system, and the method 200 may include some or all of the following content.

[0062] S210, obtaining the current of at least one of the N battery clusters.

[0063] S220, when the energy storage system is in a stationary state, determining an overcurrent level of the energy storage system according to the current of a first battery cluster among the at least one battery cluster, where the first battery cluster is the battery cluster with the largest current among the at least one battery cluster.

[0064] S230, controlling the energy storage system according to the overcurrent level.

[0065] Generally, the BMS can monitor the status of each battery cluster in the energy storage system in real time, that is, the BMS can periodically obtain the status information of each battery cluster in the energy storage system. For example, the BMS can obtain the voltage, current, or SOC of each battery cluster in the energy storage system. In the embodiments of the present application, the BMS can obtain the current of at least one battery cluster among N battery clusters, and the at least one battery cluster can be all the battery clusters in the energy storage system or part of the battery clusters. For example, if the relays of all N battery clusters in the current energy storage system are closed, then the at least one battery cluster is N battery clusters. For another example, if the relays of (N - 1) battery clusters in the current energy storage system are closed and the relay of one battery cluster is open, then the at least one battery cluster is (N - 1) battery clusters. The disconnection of the relay of a battery cluster means that the battery cluster does not participate in the circulating current equalization.

[0066] After the charge and discharge of the energy storage system are completed, it usually enters a static stage. During the static stage, there may be differences in the terminal voltages of each battery cluster in the energy storage system, which leads to the occurrence of a circulating current phenomenon between the battery clusters. It should be noted that a circulating current may also occur when the energy storage system is in a normal charge and discharge state, but this circulating current is usually small and has little impact on the energy storage system. Therefore, the embodiments of the present application mainly control the circulating current that occurs when the energy storage system is in a static state.

[0067] In some embodiments, when the energy storage system is in a static state, the BMS still monitors the status of each battery cluster in the energy storage system in real time to obtain the current of at least one battery cluster among N battery clusters, and determines the overcurrent level of the energy storage system based on the current of the battery cluster with the largest current among the at least one battery cluster (for example, the first battery cluster). For example, a first threshold and a second threshold can be set in advance. The first threshold is the threshold value for the occurrence of a mild circulating current, and the second threshold is the threshold value for the occurrence of a severe circulating current. The first threshold and the second threshold can be adjusted according to the actual operating conditions and control strategies. The BMS first determines the maximum current from the currents of the at least one monitored battery cluster, and the battery cluster corresponding to the maximum current can be called the first battery cluster. Then, the BMS can classify the circulating current occurring in the energy storage system based on the comparison of the current of the first battery cluster with the first threshold and the second threshold. For example, if the current of a certain battery cluster is between the first threshold and the second threshold, it can be considered that the energy storage system has a first-level overcurrent fault. For another example, if the current of a certain battery cluster is greater than the second threshold, it can be considered that the energy storage system has an overcurrent fault above the first level.

[0068] After determining the overcurrent level of the energy storage system, the BMS can further control the energy storage system. The so-called control of the energy storage system refers to the self-balancing control of the energy storage system in a static state when a circulating current occurs. For example, controlling the energy storage system to achieve SOC balance. For another example, controlling the energy storage system not to overcharge or over-discharge during the circulating current process. For instance, for a first-level overcurrent fault, the BMS can temporarily take no measures to see if SOC balance can be achieved through the circulating current. For overcurrent faults above the first level, the BMS can adopt some measures to monitor the energy storage system to prevent the energy storage system from overcharging or over-discharging during the circulating current process until the energy storage system is balanced. Other control strategies can also be adopted for the energy storage system to avoid the hidden danger that this imbalance increases the phenomena of uneven current or overcurrent during the charge and discharge of the energy storage system. For example, the next charge and discharge control strategy can be adjusted. For another example, before the next charge and discharge, the abnormal battery cluster in the energy storage system can be replaced.

[0069] In this embodiment, when the energy storage system is in a static state, the BMS determines the overcurrent level of the energy storage system according to the current with the largest value in at least one battery cluster, and controls the energy storage system based on this overcurrent level. For example, different control strategies are adopted for different overcurrent levels, which is beneficial to reducing the inconsistency between battery clusters, further beneficial to reducing the hidden danger of uneven current or overcurrent caused by SOC inconsistency in the energy storage system, and at the same time beneficial to solving the problems of inconsistent battery aging rates or reduced available battery power caused by SOC inconsistency.

[0070] In some embodiments, as Figure 3 shown, S220, that is, determining the overcurrent level of the energy storage system according to the current of the first battery cluster in at least one battery cluster, includes: S221, when the current of the first battery cluster is greater than the first threshold and less than the second threshold, determining that the energy storage system has a first-level overcurrent fault; or, S222, when the current of the first battery cluster is not less than the second threshold and the fault parameter is less than the third threshold, determining that the energy storage system has a second-level overcurrent fault, where the fault parameter is used to indicate the number of overcurrent faults above the first level that occur in the energy storage system; or, S223, when the current of the first battery cluster is not less than the second threshold and the fault parameter is not less than the third threshold, determining that the energy storage system has a third-level overcurrent fault.

[0071] A variable representing a fault parameter can be pre-configured with an initial value of 0. At the same time, a third threshold can be set according to the actual working conditions and control strategy of the energy storage system. Each time an overcurrent fault above the first level occurs in the energy storage system, the fault parameter is incremented by 1. Then, based on the updated fault parameter, the relationship between it and the third threshold is judged, and the overcurrent faults above the first level are further divided into second-level overcurrent faults and third-level overcurrent faults. After the value of the fault parameter is not less than the third threshold, the fault parameter can be cleared and the accumulation starts again.

[0072] Specifically, it can be first judged whether the current of the first battery cluster is between the first threshold and the second threshold. If the current of the first battery cluster is between the first threshold and the second threshold, it can be considered that the energy storage system should be able to achieve balance through the circulating current in the static state stage, and its overcurrent level is set as the first-level overcurrent fault. When the current of the first battery cluster exceeds the second threshold, in addition to incrementing the fault parameter by 1, it is also necessary to further judge whether the updated fault parameter exceeds the third threshold. If it does not exceed, it can be considered that the energy storage system is expected to achieve balance through the circulating current in the static state stage by adjusting a certain control strategy, and its overcurrent level is set as the second-level overcurrent fault; when the updated fault parameter exceeds the third threshold, it can be considered that there is still a large SOC imbalance between clusters in the energy storage system after multiple circulating currents in the static state stage, and its overcurrent level is set as the third-level overcurrent fault.

[0073] That is to say, after the circulating current phenomenon occurs in the energy storage system in the static state, it can first conduct a preliminary classification and early warning of the possible overcurrent problems in the subsequent charge and discharge processes of the energy storage system by monitoring the current magnitude of the battery cluster, and then further classify and early warn the overcurrent problems according to the number of relatively serious occurrences of the circulating current. In this way, the degree of inconsistency of the battery parameters in the energy storage system can be accurately judged, and different control strategies can be made accordingly.

[0074] In this embodiment, based on the magnitude of the current of the battery cluster with the largest current in at least one battery cluster and the magnitude of the fault parameter, the overcurrent level of the energy storage system is at least divided into 3 levels. According to different overcurrent levels, different control strategies can be implemented for the energy storage system, which is beneficial to adjusting the SOC between each battery cluster of the energy storage system to the balanced state to the greatest extent without increasing the cost, and improving the overall life of the energy storage system.

[0075] In some embodiments, such as Figure 3As shown, S230, that is, controlling the energy storage system according to the overcurrent level, includes: S231, in the case that the energy storage system has a second-level overcurrent fault, reducing the charging rate of the energy storage system so as to charge the energy storage system for the next time; or, in the case that the energy storage system has a second-level overcurrent fault, reducing the discharging rate of the energy storage system so as to discharge the energy storage system for the next time.

[0076] It should be explained that reducing the charging rate of the energy storage system to charge the energy storage system for the next time means that the charging device charges the energy storage system with a reduced current. For example, if the charging rate of the energy storage system before the previous static state is 1C, then in the case that the energy storage system has a second-level overcurrent fault, the charging rate can be reduced to 0.8C. Reducing the discharging rate of the energy storage system to discharge the energy storage system for the next time means that the discharging device discharges with a reduced current. For example, if the discharging rate of the energy storage system before the previous static state is 1C, then in the case that the energy storage system has a second-level overcurrent fault, the discharging rate can be reduced to 0.8C.

[0077] Optionally, when charging or discharging the energy storage system at a reduced rate, different levels of charging rates or discharging rates can be selected. For example, the BMS can store two charging rates of 0.5C and 0.8C. In the case that the energy storage system has a second-level overcurrent fault for the first time, the charging rate of 0.8C can be defaultly used to charge the energy storage system for the next time, and in the case that the energy storage system has a second-level overcurrent fault again, the charging rate of 0.5C can be used to charge the energy storage system for the next time, and so on.

[0078] It should be noted that charging the energy storage system at a reduced charging rate for the next time can mean charging the energy storage system with the reduced charging rate throughout the entire process of the next charging, or only using the reduced charging rate at the end of the next charging; similarly, discharging the energy storage system at a reduced discharging rate for the next time can mean discharging the energy storage system with the reduced discharging rate throughout the entire process of the next discharging, or only using the reduced discharging rate at the end of the next discharging.

[0079] In this embodiment, in the case that the energy storage system has a second-level overcurrent fault, the energy storage system can be charged or discharged at a reduced rate during the next charging or discharging. By adjusting this strategy, the inconsistency phenomenon between battery clusters in the energy storage system can be effectively alleviated at the end of charging or discharging, and the SOC difference between battery clusters can be reduced.

[0080] In other embodiments, such as Figure 3As shown in S230, according to the overcurrent level, the energy storage system is controlled, including: S232, in the case of a third-level overcurrent fault occurring in the energy storage system, cutting off the main relay of the energy storage system to adjust the abnormal battery cluster in the energy storage system.

[0081] For example, once it is determined that a third-level overcurrent fault has occurred in the energy storage system, the BMS can control the main relay of the energy storage system to disconnect, that is, control the energy storage system to disconnect from the charging device or the discharging device. Then, the abnormal battery cluster in the energy storage system can be found, and according to the difference in the DC resistance from other battery clusters, the electrical box in the abnormal battery cluster can be replaced, so that the DC resistance of the abnormal battery cluster is adjusted to a level balanced with other battery clusters.

[0082] After adjusting the abnormal battery cluster in the energy storage system, the energy storage system can be connected to the charging device or the discharging device again, and then the various embodiments provided in this application can be used again to control the energy storage system.

[0083] Further referring to Figure 3 , the method 200 further includes: S240, in the case of an overcurrent fault above the first level occurring in the energy storage system, storing the identifier of the first battery cluster, and this identifier is used to determine the abnormal battery cluster.

[0084] For the energy storage system, the N battery clusters each have an identifier. For example, the N battery clusters are respectively identified by 1, 2,..., N. If in a control of an embodiment of this application, the identifier of the first battery cluster with the largest current is i, and the current of this first battery cluster is not less than the second threshold, then the value of i is recorded, and i is any positive integer from 1 to N. And every time an overcurrent fault above the first level occurs, the BMS records the identifier of a first battery cluster. The identifier of the first battery cluster recorded each time may be the same or different until a third-level overcurrent fault occurs in the energy storage system and based on the recorded identifier of the first battery cluster (including the identifier of the first battery cluster recorded this time and the identifiers of the first battery clusters recorded before), the electrical box of the abnormal battery cluster is replaced. Optionally, after replacing the electrical box of the abnormal battery cluster based on the recorded identifier of the first battery cluster, the identifier of the first battery cluster stored inside the BMS can be cleared, and the recording of the identifier of the first battery cluster when an overcurrent fault above the first level occurs in the energy storage system in a new round of control can be restarted.

[0085] In this embodiment, in the case of an overcurrent fault above the first level occurring in the energy storage system, the identifier of the first battery cluster is stored, so that once it is determined that a third-level overcurrent fault has occurred in the energy storage system, the BMS can quickly lock the abnormal battery cluster.

[0086] Optionally, as Figure 4As shown, the method 200 further includes: S250, sending a first instruction to the energy management system, where the first instruction is used to indicate the overcurrent level of the energy storage system.

[0087] In some embodiments, after determining the overcurrent level of the energy storage system, the BMS can independently send an instruction indicating the overcurrent level to the Energy Management System (EMS). In other embodiments, after determining that the energy storage system has an overcurrent, the BMS can also send an instruction to pause charge and discharge to the EMS. At this time, the overcurrent level of the energy storage system can also be carried in the instruction to save signaling overhead.

[0088] In this embodiment, when there is a circulating current in the energy storage system, the BMS sends a first instruction indicating the overcurrent level of the energy storage system to the EMS, which is beneficial for the EMS to timely adjust the control strategy of the energy storage system according to the current overcurrent situation of the energy storage system, thereby improving the balance between battery clusters in the energy storage system.

[0089] Optionally, as Figure 5 shown, S220, that is, when the energy storage system is in a static state, determining the overcurrent level of the energy storage system according to the current of the first battery cluster in at least one battery cluster includes: S224, when the energy storage system is in a static state, determining whether there is a battery cluster in the at least one battery cluster whose current is greater than a first threshold; S225, when it is determined that there is a battery cluster in the at least one battery cluster whose current is greater than the first threshold, determining the overcurrent level of the energy storage system according to the battery of the first battery cluster.

[0090] When the energy storage system is in a static state, the BMS can judge whether there is a circulating current in the energy storage system based on the current of at least one battery cluster obtained. Once there is a circulating current in one of the at least one battery cluster, it is considered that there is a potential hidden danger of overcharge and over-discharge in the energy storage system at present, and it needs to be controlled. Specifically, a first threshold can be set in advance according to the actual operating conditions and control strategies of the energy storage system, such as product type, operating rate, voltage range, number of parallel battery clusters N, etc. Once it is monitored that the current of one battery cluster is greater than the first threshold, it can be considered that there is a circulating current in the energy storage system, and then some measures may need to be further taken for the energy storage system. If the current of each battery cluster in the at least one battery cluster is below the first threshold, it can be considered that there is no circulating current or no circulating current with hidden danger in the energy storage system, and no measures need to be taken for the energy storage system. Once the BMS determines that the energy storage system has a circulating current, it can further determine the overcurrent level of the energy storage system based on the current of the first battery cluster.

[0091] In this embodiment, when the energy storage system is in a static state, it is first determined whether there is a current in at least one battery cluster greater than a first threshold. Only when there is a current in a battery cluster greater than the first threshold, the overcurrent level of the energy storage system is further determined based on the current of the first battery cluster. Compared with the solution of directly performing overcurrent classification on the energy storage system based on the current of the first battery cluster, the computing amount of the BMS is reduced when there is no circulating current in the energy storage system at all.

[0092] In some embodiments, S224, when the energy storage system is in a static state, determining whether there is a current in at least one battery cluster greater than a first threshold includes: when the energy storage system is in a static state, determining whether the current of the first battery cluster is greater than the first threshold.

[0093] That is to say, as long as it is determined that the current of the battery cluster with the largest current in at least one battery cluster is greater than the first threshold, it can be considered that there is a circulating current in the energy storage system. That is, only the current of the battery cluster with the largest current in at least one battery cluster needs to be concerned, which is beneficial to performing overcurrent classification on the energy storage system before a safety risk occurs, and controlling the energy storage system based on the overcurrent classification, so as to reduce the probability of uneven current or overcurrent in the energy storage system caused by the inconsistency of battery parameters in the energy storage system.

[0094] In some embodiments, as Figure 4 shown, method 200 further includes: S260, when the allowable current of the energy storage system is equal to 0, determining that the energy storage system is in a static state.

[0095] Generally, when charging the energy storage system, the BMS will appropriately adjust the allowable current according to the monitored state of the energy storage system. For example, if the BMS monitors that there is a risk of circulating current in the energy storage system, it can appropriately reduce the allowable current, or even adjust it to 0. Further, the BMS can send the allowable current to the Process Control System (PCS) for execution. For example, the BMS will send the allowable total charging current to the PCS, and then can distribute the allowable charging current to each battery cluster according to Ohm's law; similarly, when discharging the energy storage system, the BMS will send the allowable discharge current to the PCS, and then can distribute the allowable discharge current to each battery cluster according to Ohm's law. When the BMS determines that the allowable charging current or the allowable discharge current is close to 0, it can be considered that the energy storage system is in a static state. Then the BMS can use the above various embodiments to perform circulating current control on the energy storage system.

[0096] Figure 6 shows a schematic flowchart of a method 300 for controlling an energy storage system according to an embodiment of the present application. As Figure 6As shown, the method 300 includes the following parts or all of the following content.

[0097] S301, the BMS sets the fault parameter M to 0.

[0098] S302, the BMS determines whether the energy storage system is in a static state. Specifically, the BMS can determine whether the energy storage system is in a static state based on the allowed current. If the allowed current is approximately equal to 0, it can be considered that the energy storage system is in a static state.

[0099] S303, if it is determined that the energy storage system is not in a static state, the BMS considers that the energy storage system is in the normal charge and discharge stage and does not process the energy storage system.

[0100] S304, if it is determined that the energy storage system is in a static state, the BMS can further determine the current I of the battery cluster with the largest current in the energy storage system max whether it is greater than the first threshold I1.

[0101] S305, if I max is not greater than I1, the BMS can consider that there is no circulating current and does not process the energy storage system.

[0102] S306, if I max is greater than I1, the BMS can consider that a circulating current has occurred during the static process of the energy storage system.

[0103] S307, the BMS further determines whether the current I of the battery cluster with the largest current in the energy storage system max is less than the second threshold I2.

[0104] S308, if I max is less than I2, the BMS reports to the EMS and issues a level 1 overcurrent warning.

[0105] S309, if I max is not less than I2, the BMS updates the fault parameter M. Specifically, M = M + 1 can be set.

[0106] S310, the BMS further determines whether the fault parameter M is greater than the third threshold a.

[0107] S311, if M is not greater than a, the BMS reports to the EMS and issues a level 2 overcurrent warning.

[0108] S312, after issuing the level 2 overcurrent warning, the BMS can adjust the next charging strategy and introduce a step-down charging strategy at the end of the next charge.

[0109] S313, if M is greater than a, the BMS reports to the EMS and issues a level 3 overcurrent warning.

[0110] In S314, the BMS controls the disconnection of the main relay, locates the abnormal battery cluster, and replaces the electrical box with abnormal DC resistance.

[0111] It should be noted that in S312 and S314, the BMS can obtain the identification i of the battery cluster with the largest current in the energy storage system to quickly locate the abnormal battery cluster.

[0112] The method for controlling the energy storage system according to the embodiments of the present application has been described in detail above. Next, in combination with Figure 7 and Figure 8 the device for controlling the energy storage system according to the embodiments of the present application will be described in detail. The technical features described in the method embodiments are applicable to the following device embodiments.

[0113] Figure 7 FIG. shows a schematic block diagram of a device 400 for controlling an energy storage system according to an embodiment of the present application. Among them, the energy storage system includes N battery clusters connected in parallel. As Figure 7 shown, the device 400 includes the following parts or all of the content.

[0114] An acquisition unit 410, configured to acquire the current of at least one battery cluster among the N battery clusters;

[0115] A determination unit 420, configured to determine the overcurrent level of the energy storage system according to the current of the first battery cluster among at least one battery cluster when the energy storage system is in a stationary state, where the first battery cluster is the battery cluster with the largest current among at least one battery cluster;

[0116] A control unit 430, configured to control the energy storage system according to the overcurrent level.

[0117] In a possible embodiment, the determination unit 420 is specifically configured to: determine that the energy storage system has a first-level overcurrent fault when the current of the first battery cluster is greater than a first threshold and less than a second threshold; or, determine that the energy storage system has a second-level overcurrent fault when the current of the first battery cluster is not less than the second threshold and the fault parameter is less than a third threshold, where the fault parameter is used to indicate the number of overcurrent faults above the first level that have occurred in the energy storage system; or, determine that the energy storage system has a third-level overcurrent fault when the current of the first battery cluster is not less than the second threshold and the fault parameter is not less than the third threshold.

[0118] In a possible embodiment, the control unit 430 is specifically configured to: reduce the charging rate of the energy storage system in the case of a second-level overcurrent fault of the energy storage system for the next charge; or reduce the discharge rate of the energy storage system in the case of a second-level overcurrent fault of the energy storage system for the next discharge.

[0119] In a possible embodiment, the control unit 430 is specifically configured to: when a third-level overcurrent fault occurs in the energy storage system, cut off the main relay of the energy storage system to adjust the abnormal battery cluster in the energy storage system.

[0120] In a possible embodiment, as Figure 8 shown, the device 400 further includes: a storage unit 440, configured to store the identifier of the first battery cluster when a third-level overcurrent fault occurs in the energy storage system, and the identifier is used to determine the abnormal battery cluster.

[0121] In a possible embodiment, as Figure 8 shown, the device 400 further includes: a sending unit 450, configured to send a first instruction to the energy management system, and the first instruction is used to indicate the overcurrent level of the energy storage system.

[0122] In a possible embodiment, the determining unit 420 is specifically configured to: when the energy storage system is in a stationary state, determine whether there is a battery cluster in at least one battery cluster whose current is greater than a first threshold; when it is determined that there is a battery cluster in at least one battery cluster whose current is greater than the first threshold, determine the overcurrent level of the energy storage system according to the current of the first battery cluster.

[0123] In a possible embodiment, the determining unit 420 is specifically configured to: when the energy storage system is in a stationary state, determine whether the current of the first battery cluster is greater than the first threshold.

[0124] In a possible embodiment, the determining unit 420 is further configured to: when the allowable current of the energy storage system is equal to 0, determine that the energy storage system is in a stationary state.

[0125] It should be understood that each of the above modules in the device 400 is used to implement Figures 2 to 6 the corresponding processes in each of the methods, and for the sake of brevity, they will not be elaborated here.

[0126] Figure 9 Fig. shows a schematic block diagram of a system 500 for controlling an energy storage system according to an embodiment of the present application. As Figure 9 shown, the system 500 includes a processor 510 and a memory 520. Among them, the memory 520 is used to store instructions, and the processor 510 is used to read the instructions and execute the methods of various embodiments of the present application based on the instructions.

[0127] Among them, the memory 520 can be a separate device independent of the processor 510, or can be integrated in the processor 510.

[0128] Optionally, as Figure 9As shown, the system 500 may further include a transceiver 530, and the processor 510 may control the transceiver 530 to communicate with other devices. Specifically, information or data may be sent to other devices, or information or data sent by other devices may be received.

[0129] It should be understood that the processor in the embodiments of the present application may be an integrated circuit chip with signal processing capabilities. In the implementation process, the steps of the above method embodiments may be completed by the integrated logic circuit in the hardware of the processor or instructions in software form. The above processor may be a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. The various methods, steps and logic block diagrams disclosed in the embodiments of the present application may be implemented or executed. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The steps of the method disclosed in combination with the embodiments of the present application may be directly embodied as being executed by a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software module may be located in a mature storage medium in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory, and the processor reads the information in the memory and combines its hardware to complete the steps of the above method.

[0130] It can be understood that the memory in the embodiments of the present application can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory can be a random access memory (RAM), which is used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchlink dynamic random access memory (SLDRAM), and direct rambus random access memory (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to include but not be limited to these and any other suitable types of memory.

[0131] The embodiments of the present application also provide a computer-readable storage medium for storing a computer program.

[0132] Optionally, the computer-readable storage medium can be applied to the control system of the energy storage system in the embodiments of the present application, and the computer program causes the computer to execute the corresponding processes implemented by the control system in the various methods of the embodiments of the present application. For the sake of brevity, details are not described herein again.

[0133] The embodiments of the present application also provide a computer program product, including computer program instructions.

[0134] Optionally, the computer program product can be applied to the control system of the energy storage system in the embodiments of the present application, and the computer program instructions cause the computer to execute the corresponding processes implemented by the control system in the various methods of the embodiments of the present application. For the sake of brevity, details are not described herein again.

[0135] The embodiments of the present application also provide a computer program.

[0136] Optionally, the computer program can be applied to the control system of the energy storage system in the embodiments of the present application. When the computer program runs on a computer, it causes the computer to execute the corresponding processes implemented by the control system in each method of the embodiments of the present application. For the sake of brevity, it will not be elaborated here.

[0137] In several embodiments provided in the present application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical, or other forms.

[0138] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0139] In addition, in each embodiment of the present application, the functional units can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit.

[0140] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art or part of this technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, ROM, RAM, magnetic disks, or optical discs that can store program codes.

[0141] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for controlling an energy storage system, characterized in that, The energy storage system includes N battery clusters connected in parallel, where N is a positive integer greater than 1. The method includes: Obtaining the current of at least one battery cluster among the N battery clusters; When the energy storage system is in a stationary state, determining the overcurrent level of the energy storage system according to the current of the first battery cluster among the at least one battery cluster, where the first battery cluster is the battery cluster with the largest current among the at least one battery cluster; Controlling the energy storage system according to the overcurrent level.

2. The method according to claim 1, characterized in that The determining the overcurrent level of the energy storage system according to the current of the first battery cluster among the at least one battery cluster includes: When the current of the first battery cluster is greater than the first threshold and less than the second threshold, determining that the energy storage system has a first-level overcurrent fault; or When the current of the first battery cluster is not less than the second threshold and the fault parameter is less than the third threshold, determining that the energy storage system has a second-level overcurrent fault, where the fault parameter is used to indicate the number of overcurrents above the first-level overcurrent fault that occurred in the energy storage system; or When the current of the first battery cluster is not less than the second threshold and the fault parameter is not less than the third threshold, determining that the energy storage system has a third-level overcurrent fault.

3. The method according to claim 2, characterized in that, The controlling the energy storage system according to the overcurrent level includes: When the energy storage system has the second-level overcurrent fault, reducing the charging rate of the energy storage system for the next charge; or When the energy storage system has the second-level overcurrent fault, reducing the discharging rate of the energy storage system for the next discharge.

4. The method according to claim 2, wherein The controlling the energy storage system according to the overcurrent level includes: When the energy storage system has the third-level overcurrent fault, cutting off the main circuit relay of the energy storage system to adjust the abnormal battery cluster in the energy storage system.

5. The method according to claim 3 or 4, characterized in that, The method further includes: When the energy storage system has an overcurrent fault above the first level, storing the identifier of the first battery cluster, where the identifier is used to determine the abnormal battery cluster.

6. The method according to any one of claims 1 to 5, characterized in that, The method further includes: Sending a first instruction to the energy management system, where the first instruction is used to indicate the overcurrent level of the energy storage system.

7. The method according to any one of claims 1 to 6, characterized in that The determining the overcurrent level of the energy storage system according to the current of the first battery cluster among the at least one battery cluster when the energy storage system is in a stationary state includes: When the energy storage system is in the stationary state, determining whether there is a battery cluster among the at least one battery cluster whose current is greater than the first threshold; When it is determined that there is a battery cluster among the at least one battery cluster whose current is greater than the first threshold, determining the overcurrent level of the energy storage system according to the current of the first battery cluster.

8. The method according to claim 7, characterized in that The determining whether there is a battery cluster among the at least one battery cluster whose current is greater than the first threshold when the energy storage system is in a stationary state includes: When the energy storage system is in the stationary state, determining whether the current of the first battery cluster is greater than the first threshold.

9. The method according to any one of claims 1 to 8, characterized in that The method further includes: When the allowable current of the energy storage system is equal to 0, it is determined that the energy storage system is in the stationary state.

10. A device for controlling an energy storage system, characterized in that, The energy storage system includes N battery clusters connected in parallel, where N is a positive integer greater than 1. The device includes: An acquisition unit for acquiring the current of at least one battery cluster among the N battery clusters; A determination unit for determining the overcurrent level of the energy storage system according to the current of the first battery cluster among the at least one battery cluster when the energy storage system is in the stationary state, where the first battery cluster is the battery cluster with the largest current among the at least one battery cluster; A control unit for controlling the energy storage system according to the overcurrent level.

11. The device according to claim 10, characterized in that, Specifically, the determination unit is used for: When the current of the first battery cluster is greater than the first threshold and less than the second threshold, determining that the energy storage system has a first-level overcurrent fault; or When the current of the first battery cluster is not less than the second threshold and the fault parameter is less than the third threshold, determining that the energy storage system has a second-level overcurrent fault, where the fault parameter is used to indicate the number of overcurrent faults above the first level that occur in the energy storage system; Or When the current of the first battery cluster is not less than the second threshold and the fault parameter is not less than the third threshold, determining that the energy storage system has a third-level overcurrent fault.

12. The device according to claim 11, wherein, Specifically, the control unit is used for: When the energy storage system has the second-level overcurrent fault, reducing the charging rate of the energy storage system for the next charge; or When the energy storage system has the second-level overcurrent fault, reducing the discharge rate of the energy storage system for the next discharge.

13. The device according to claim 11 or 12, characterized in that, Specifically, the control unit is used for: When the energy storage system has the third-level overcurrent fault, cutting off the main circuit relay of the energy storage system to adjust the abnormal battery cluster in the energy storage system.

14. The device according to claim 13, characterized in that, The device further includes: A storage unit for storing the identifier of the first battery cluster when the energy storage system has the third-level overcurrent fault, where the identifier is used to determine the abnormal battery cluster.

15. The device according to any one of claims 10 to 14, characterized in that The device further includes: A sending unit for sending a first instruction to the energy management system, where the first instruction is used to indicate the overcurrent level of the energy storage system.

16. The device according to any one of claims 10 to 15, characterized in that, Specifically, the determination unit is used for: When the energy storage system is in the stationary state, determining whether there is a battery cluster among the at least one battery cluster whose current is greater than the first threshold; When it is determined that there is a battery cluster among the at least one battery cluster whose current is greater than the first threshold, determining the overcurrent level of the energy storage system according to the current of the first battery cluster.

17. The device according to claim 16, characterized in that, Specifically, the determination unit is used for: When the energy storage system is in the stationary state, determining whether the current of the first battery cluster is greater than the first threshold.

18. The device according to any one of claims 10 to 17, characterized in that The determination unit is further used for: When the allowable current of the energy storage system is equal to 0, determining that the energy storage system is in the stationary state.

19. A system for controlling an energy storage system, characterized in that, It includes: A memory for storing instructions; A processor for reading the instructions and executing the method according to any one of claims 1 to 9 based on the instructions.

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