Energy storage system and control method therefor

Abstract

The present application relates to the technical field of energy storage. Specifically disclosed are an energy storage system and a control method therefor. The energy storage system comprises a plurality of branches. The control method for the energy storage system comprises: acquiring a power-on request; in response to the power-on request, acquiring state information of all battery clusters on each branch, wherein the state information at least comprises an internal sampling voltage; and for any branch, on the basis of the state information of all the battery clusters on the branch, sending a power-on instruction to one of the battery clusters on the branch or to a plurality of voltage-equalized battery clusters on the branch, wherein the power-on instruction is used for instructing the corresponding battery cluster to execute a power-on operation. By means of the control method of the present invention, there is one battery cluster or a plurality of voltage-equalized battery clusters on each branch to implement a power-on process, such that all the branches can be powered on. Compared with the relevant art in which some branches cannot be powered on, the control method can increase the external discharge capacity of the energy storage system. Moreover, the possibility of the battery clusters on the branches being damaged due to the generation of a circulating current on the branches can be reduced.

Description

Energy storage systems and their control methods

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411021343.6, filed on July 29, 2024, entitled “Energy Storage System and Control Method Thereof,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of energy storage technology, and in particular to an energy storage system and its control method. Background Technology

[0004] Energy storage systems use media or devices to store excess electrical energy when there is a surplus, and release the stored energy when there is a shortage, thus solving the problems of grid fluctuations and supply instability. When an energy storage system consists of multiple branches, and each branch includes multiple battery clusters, if the difference in the internal sampling voltage of each battery cluster is large, in order to reduce the possibility of circulating currents between battery clusters that could damage them, some branches will not be energized, resulting in low external discharge capacity of the energy storage system. Summary of the Invention

[0005] In view of the above problems, this application provides an energy storage system and its control method, which solves the problem that the energy storage system has low external discharge capacity due to some branches not being powered.

[0006] The first aspect of this application proposes a control method for an energy storage system. The energy storage system includes N branches and at least one energy storage converter. Each branch is provided with multiple independent battery clusters. Each battery cluster includes at least one battery pack. N is a positive integer greater than or equal to 2. Each energy storage converter is electrically connected to K branches, and each branch can be charged or discharged through the corresponding energy storage converter. K is a positive integer. When K is greater than or equal to 2 and less than or equal to N, the K branches are connected in parallel.

[0007] Control methods for energy storage systems include:

[0008] Obtain a power-on request;

[0009] In response to a power-on request, acquire the status information of all battery clusters on each branch, including at least the internal sampled voltage; and

[0010] For any one of the N branches, based on the status information of all battery clusters on the branch, a power-on command is sent to one of the battery clusters on the branch or to all M battery clusters on the branch that meet the voltage balance requirement. M is a positive integer greater than or equal to 2. Voltage balance means that the voltage value related to a certain battery cluster among the M is the reference voltage, and the difference between the internal sampled voltage of the remaining battery clusters among the M and the reference voltage is less than a first threshold. The power-on command is used to instruct the corresponding battery cluster to perform a power-on operation.

[0011] In this application, in response to a power-on request, each branch independently performs its power-on process, and the power-on logic of each branch does not affect each other. Furthermore, for any given branch, if the voltages of M battery clusters are balanced, then power-on control is implemented for all M battery clusters; if the voltages of any two battery clusters are unbalanced, then power-on control is implemented for only one battery cluster. Thus, at least one battery cluster in each branch is powered on, ensuring that all N branches can be powered on. Compared to related technologies where some branches cannot be powered on, this increases the external discharge capacity of the energy storage system. Simultaneously, it minimizes the possibility of circulating currents in branches damaging the battery clusters within those branches.

[0012] In some embodiments of this application, for any one of the N branches, based on the state information of all battery clusters on the branch, a power-on command is sent to one battery cluster on the branch or to all M battery clusters on the branch that meet voltage equalization, including:

[0013] For any one of the N branches, the first battery cluster is determined from all battery clusters based on the state information of all battery clusters on the branch.

[0014] Send a power-on command to the first battery cluster;

[0015] If the first battery cluster is successfully powered on, confirm whether there is a second battery cluster on the branch. The voltage of the second battery cluster is equal to that of the first battery cluster, and the reference voltage is related to that of the first battery cluster.

[0016] In response to the presence of a second battery cluster on the branch, a power-on command is sent to the second battery cluster.

[0017] In this embodiment, each branch first performs a power-on operation on a single battery cluster (i.e., the first battery cluster), ensuring that no circulating current is generated during the power-on phase of a single battery cluster. If the first battery cluster is successfully powered on, during the power-on phase of the second battery cluster, the voltage of the first and second battery clusters is balanced, minimizing the possibility of circulating current between them, which is beneficial for improving the operational stability of the energy storage system.

[0018] In some embodiments of this application, the status information also includes an externally sampled voltage;

[0019] If the first battery cluster is successfully powered on, confirm the presence of a second battery cluster on the branch. The voltage of the second battery cluster is equal to that of the first battery cluster, and the reference voltage is related to that of the first battery cluster, specifically including:

[0020] If the first battery cluster is successfully powered on, the reference voltage is obtained. The reference voltage is the external sampling voltage of the first battery cluster.

[0021] On the branch, among the other battery clusters, is there any battery cluster whose internal sampling voltage and reference voltage have an absolute value less than the first threshold?

[0022] Based on the judgment results, it was confirmed whether a second battery cluster exists.

[0023] By designing the second battery cluster to ensure that the absolute value of the difference between its internal sampling voltage and the external sampling voltage of the first battery cluster is less than a first threshold, the internal sampling voltage of the selected second battery cluster is balanced with the external sampling voltage of the first battery cluster that has been successfully powered on. This can more accurately reduce the risk of high voltage surge to the energy storage converter caused by excessive voltage difference between the second battery cluster and the energy storage converter.

[0024] In some embodiments of this application, each branch is provided with at least three battery clusters;

[0025] The first battery cluster is identified among all battery clusters, specifically including:

[0026] The battery cluster whose internal sampled voltage is in the middle position among all battery clusters is determined as the first battery cluster.

[0027] Designing the first battery cluster to be a cluster whose internal sampling voltage magnitude is in the middle position can increase the number of the second battery clusters, which in turn helps to increase the number of battery clusters that can perform power-on operations on the branch, thus increasing the possibility of each branch being powered on and increasing the external discharge capacity of the energy storage system.

[0028] In some embodiments of this application, the status information also includes fault information;

[0029] Sending a power-on command to one of the battery clusters on the branch, or to all M battery clusters on the branch that meet voltage equalization, specifically involves:

[0030] Send a power-on command to one of the battery clusters on the branch that meets the allowed power-on conditions, or send a power-on command to all M battery clusters on the branch that meet the allowed power-on conditions and have equal voltage; wherein the allowed power-on conditions include a fault level lower than a first set level.

[0031] By designing the system to send power-on commands to battery clusters that meet the permissible power-on conditions on the branch, the battery clusters that receive the power-on commands and perform the power-on operation must meet the permissible power-on conditions. This eliminates the need to send power-on commands to battery clusters that do not meet the permissible power-on conditions, which helps to simplify the control process of the energy storage system.

[0032] In some embodiments of this application, the power-on duration of the battery cluster is timed while a power-on command is sent to any one of the battery clusters.

[0033] In response to the battery cluster completing the power-on operation within a first preset time period, the power-on of the battery cluster is confirmed to be successful.

[0034] By setting a first preset duration as a threshold, it is confirmed whether the power-on time of the battery cluster is too long, so that the power-on time of the battery cluster that is successfully powered on does not exceed the first preset duration, thereby ensuring that the battery cluster that is successfully powered on functions normally. This can reduce the possibility of malfunctions or even accidents caused by powering on battery clusters that are not functioning normally.

[0035] In some embodiments of this application, the status information also includes an externally sampled voltage;

[0036] The power-on command is configured to instruct the pre-charging circuit of the corresponding battery cluster to be powered on, and to obtain the pre-charging duration, internal sampling voltage and external sampling voltage of the battery cluster.

[0037] Used to indicate and confirm whether the absolute value of the potential difference between the internal sampling voltage and the external sampling voltage of the corresponding battery cluster is less than a second threshold within the second preset time period of the precharge duration.

[0038] It is also used to indicate that, within a second preset time period, the absolute value of the potential difference between the internal sampling voltage and the external sampling voltage of the corresponding battery cluster is less than a second threshold, so that the main circuit of the battery cluster is powered on and the pre-charge circuit is disconnected.

[0039] In this embodiment, the battery cluster is precharged by energizing the pre-charging circuit before the main circuit is powered on. This helps to reduce the risk of high voltage surge to the energy storage converter caused by excessive voltage difference between the battery cluster and the energy storage converter.

[0040] In some embodiments of this application, after sending a power-on command to one battery cluster or to all M voltage-equalized battery clusters on any of the N branches based on the status information of all battery clusters on the branch, the method further includes:

[0041] Confirm that the total number of battery clusters that have successfully powered on is greater than or equal to the minimum number of operating battery clusters.

[0042] When the total number of battery clusters that have successfully powered on is greater than or equal to the minimum number of operating battery clusters, the energy storage system is confirmed to have been powered on.

[0043] With this configuration, the total number of battery clusters that have successfully powered on during operation of the energy storage system is greater than or equal to the minimum number of battery clusters required for operation, thus meeting design and usage requirements.

[0044] In some embodiments of this application, before obtaining a power-on request, the status information of all battery clusters on N branches is obtained, and the status information also includes fault information;

[0045] Based on the fault information of all battery clusters, the fault level of each battery cluster is determined.

[0046] Confirm whether the total number of battery clusters with a fault level lower than the second set level is greater than or equal to the minimum number of operating battery clusters.

[0047] A power-on request is obtained in response to the total number of battery clusters with a fault level lower than the second set level being greater than or equal to the minimum number of operating battery clusters.

[0048] In this embodiment, the prerequisite for the energy storage system to respond to a power-on request is that the total number of battery clusters with a fault level lower than the second set level is greater than or equal to the minimum number of operating battery clusters. This reduces the possibility of powering on battery clusters in a severely faulty state, which is beneficial to improving the safety of the energy storage system.

[0049] The second aspect of this application proposes an energy storage system, comprising: N branches, at least one energy storage converter, and a control unit; each branch is provided with multiple battery clusters, each battery cluster including at least one battery pack, where N is a positive integer greater than or equal to 2; each energy storage converter is electrically connected to one branch or K branches connected in parallel, and the battery clusters of each branch can be charged or discharged through the corresponding energy storage converter, where K is a positive integer greater than or equal to 2 and less than or equal to N; the control unit is electrically connected to at least one energy storage converter, and the control unit is configured to implement the control method of any of the energy storage systems proposed in the first aspect of this application.

[0050] The third aspect of this application provides a computer device, which includes at least one memory and at least one processor communicatively connected to the at least one memory; the at least one memory stores instructions; and the at least one processor executes the instructions individually or collectively to implement the control method of any of the energy storage systems proposed in the first aspect of this application.

[0051] The fourth aspect of this application provides a computer-readable storage medium storing instructions that, when executed individually or jointly by one or more processors of a computer device, implement the control method of any of the energy storage systems proposed in the first aspect of this application.

[0052] The fifth aspect of this application provides a computer program product including instructions that, when executed individually or jointly by one or more processors of a computer device, implement the control method of any of the energy storage systems proposed in the first aspect of this application.

[0053] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0054] Figure 1 schematically shows a module diagram of an energy storage system according to one embodiment of this application;

[0055] Figure 2 schematically shows a block diagram of an energy storage system according to one embodiment of this application;

[0056] Figure 3 schematically illustrates an energy storage system according to one embodiment of this application;

[0057] Figure 4 schematically illustrates a schematic diagram of an energy storage system according to another embodiment of this application;

[0058] Figure 5 schematically illustrates a flow chart of a control method for an energy storage system according to one embodiment of this application;

[0059] Figure 6 schematically illustrates a flow diagram of the main control unit of an energy storage system according to one embodiment of the present application responding to a power-on command;

[0060] Figure 7 schematically illustrates a flow chart of a control method for an energy storage system according to another embodiment of this application. Detailed Implementation

[0061] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0062] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0063] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0064] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0065] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0066] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0067] The energy storage system may include an energy storage converter and multiple battery clusters. Each battery cluster may include a main control unit and at least one battery pack, and each battery pack includes at least one battery cell that is electrically connected. When a battery pack includes multiple (two or more) battery cells, the multiple battery cells may be electrically connected in parallel and / or series.

[0068] In some related technologies, one energy storage converter in an energy storage system corresponds to all battery clusters.

[0069] Understandably, when the voltages of different battery clusters differ, a large circulating current forms between the two clusters with the largest voltage difference. This circulating current can easily damage the battery clusters. To reduce the possibility of damage caused by circulating currents, existing energy storage system control methods often use the voltage of one battery cluster as a reference voltage, and control the other battery clusters whose voltages have smaller differences from the reference voltage.

[0070] However, an energy storage converter corresponds to an energy storage system for all battery clusters. When all battery clusters are powered on, the current is large. Therefore, the protection devices in the energy storage system (e.g., fuses for short-circuit protection, circuit breakers for power failure protection) need to be selected with high rated current, which leads to high requirements for protection devices and great difficulty in selection.

[0071] To address the aforementioned issues, related technologies have proposed an energy storage system composed of multiple branches, with each branch having multiple battery clusters connected in parallel. Compared to all battery clusters connected in parallel, by using multiple branches, the number of battery clusters in each branch is relatively reduced, which helps to lower the requirements for protection devices and thus reduce the difficulty of selecting protection devices. When existing control methods are applied to energy storage systems composed of multiple branches, branches with large differences between the voltage of each battery cluster and the reference voltage will not be energized, resulting in low discharge capacity of the energy storage system. Therefore, for energy storage systems composed of multiple branches, there is an urgent need to improve the control methods of the energy storage system.

[0072] This application designs an energy storage system and its control method. Upon receiving a power-on request, it can independently control each branch to perform the power-on process, ensuring that the power-on logic of each branch does not affect each other. Furthermore, for any branch, a specific battery cluster or multiple battery clusters with balanced voltage are powered on. This minimizes the possibility of circulating current in each branch, allowing all branches to be powered on, thereby increasing the external discharge capacity of the energy storage system.

[0073] The energy storage system disclosed in the embodiments of this application can be applied in power systems, and the energy storage system disclosed in this application can be used as an energy supplement to the power system.

[0074] The energy storage system disclosed in the embodiments of this application can also be applied to electrical devices, and the power system of such electrical devices can be composed of the energy storage system disclosed in this application. Electrical devices can be, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0075] For ease of explanation, the following embodiments use a power system according to an embodiment of this application as an example.

[0076] Referring to Figures 1 and 2, an energy storage system may include N branches, at least one power conversion system (PCS), and a control unit, where N is a positive integer greater than or equal to 2. The number of branches is not limited to the two shown in Figure 1 and can be customized according to actual operating conditions.

[0077] Each branch has Q battery clusters connected in parallel and independent of each other, where Q is a positive integer greater than or equal to 2. The number of battery clusters in each branch can be the same or different. Each battery cluster can be installed in an independent cabinet to protect it from the external environment. A battery cluster can include at least one battery pack, that is, a battery cluster can include one or multiple battery packs connected in series. A battery cluster can also include a main control unit (BCMU) for managing the operating status of at least one battery pack within the battery cluster. Each battery pack can include multiple battery cells electrically connected in parallel and / or series, and each battery pack can also include a battery management unit (BMU) for managing the operating status of the multiple battery cells within the battery pack.

[0078] The energy storage system can also include N busbars corresponding one-to-one with the N branches. The positive and negative terminals of each battery cluster on the same branch are connected to the positive and negative terminals of the corresponding energy storage converter through the same busbar. Referring to Figures 3 and 4, a main positive relay K+ can be installed between the positive terminal of each battery cluster and the corresponding energy storage converter, and a main negative relay K- can be installed between the negative terminal of each battery cluster and the energy storage converter. The battery clusters, main positive relays K+, main negative relays K-, and energy storage converters are connected in series to form the main circuit. The main positive relay K+ can also be connected in parallel with the pre-charge circuit, which includes a pre-charge relay S and a pre-charge resistor R connected in series.

[0079] Each energy storage converter is electrically connected to K branches, allowing each branch's battery cluster to be charged or discharged through its corresponding energy storage converter. K is a positive integer, K ≤ N. When K is greater than or equal to 2 and less than or equal to N, the K branches corresponding to the same energy storage converter are connected in parallel. Alternatively, there can be only one energy storage converter, in which case one energy storage converter is electrically connected to N branches.

[0080] There can be multiple energy storage converters, and the number of branches corresponding to each energy storage converter can be the same or different. In one embodiment, the number of energy storage converters can be the same as the number of branches, that is, the number of energy storage converters is also N, and N energy storage converters correspond one-to-one with N branches. In embodiments where N≥3 and the number of energy storage converters is not less than two, some energy storage converters can be connected to one branch, and the remaining energy storage converters can be connected to multiple branches among the N branches.

[0081] Energy storage converters are electrically connected to both power-consuming and power-generating equipment. They can charge or discharge battery clusters. Specifically, the power generation equipment charges the battery clusters in the corresponding branch via the energy storage converter, and multiple battery clusters in a branch supply power to the power-consuming equipment through their respective energy storage converters. Energy storage converters can also perform AC / DC conversion, directly supplying power to AC loads in the absence of a power grid, and can regulate the active and reactive power of the power grid.

[0082] The aforementioned control unit is used to manage the operating status of at least one energy storage converter and all battery clusters on each branch of the energy storage system.

[0083] The control unit can be configured to have communication capabilities. The control unit can communicate with at least one energy storage converter and the main control unit (BCMU) of each battery cluster via, but is not limited to, a CAN (Controller Area Network) bus or Ethernet. Specifically, taking CAN bus communication as an example, the control unit has multiple RS485 and CAN bus interfaces. The control unit connects to the main control unit (BCMU) of each battery cluster via the CAN bus. The control unit and the main control unit, as nodes on the CAN bus, can send messages (i.e., data frames, overload frames, and error frames, etc.) to the CAN bus, and can also receive entire messages when they are listened to and identified, enabling communication between the control unit and the main control units. The main control unit (BCMU) can also connect to the battery management units (BMU) within the corresponding battery cluster via the CAN bus, allowing the main control unit and the corresponding battery management units to communicate with each other as nodes on the CAN bus.

[0084] The aforementioned control unit can also be configured to have parameter configuration capabilities, allowing modification not only of its own parameters but also of control parameters via command transmission through the CAN bus. The control unit can also communicate with the backend monitoring system, uploading system information in real time and receiving monitoring commands from the backend.

[0085] The control unit, main control unit, and battery management unit can together form at least part of the battery management system (BMS). The battery management system is used to monitor the battery status and can also be used to connect to external devices.

[0086] In some embodiments, the energy storage system may further include an energy management system (EMS), and the control unit may communicate with the energy management system via, but is not limited to, a CAN bus or a device network bus. The function of the energy management system is to perform energy dispatch.

[0087] This application provides a control method for an energy storage system. This control method can be executed by the control unit of the energy storage system; that is, the execution entity of the control method is the control unit, whose function is to manage the operating status of at least one energy storage converter and all battery clusters on each branch of the energy storage system.

[0088] Figure 5 schematically illustrates a flowchart of a control method for an energy storage system according to one embodiment of this application. As shown in Figure 5, the control method mainly includes the following steps.

[0089] S110, obtain power-on request.

[0090] The power-on request can be sent by the energy storage converter or an external device. In embodiments where the energy storage system also includes an energy management system, the power-on request can be sent by the energy storage converter or an external device, or it can be sent by the energy management system.

[0091] S120, in response to a power-on request, acquires the status information of all battery clusters on each branch, including at least the internal sampled voltage Va.

[0092] As shown in Figures 3 and 4, the internal sampling voltage Va refers to the potential difference between the positive and negative terminals of the main circuit corresponding to the battery cluster when it is in an open-circuit state (the main positive relay and the main negative relay are not closed). It can also be understood as the potential difference between the first terminal of the main positive relay (terminal a, connected to the positive terminal of the battery cluster) and the first terminal of the main negative relay (terminal b, connected to the negative terminal of the battery cluster). When the battery cluster includes multiple battery groups connected in series, the internal sampling voltage Va can be understood as the sum of the voltage values ​​of the multiple battery groups included in the battery cluster when the main circuit corresponding to the battery cluster is in an open-circuit state. Since the internal sampling voltage Va refers to the potential difference between the first terminal of the main positive relay and the first terminal of the main negative relay in the open-circuit state of the main circuit corresponding to the battery cluster, the corresponding internal sampling voltage Va can be collected even when the battery cluster is not powered on.

[0093] As can be seen from the above, the battery management unit can report the status information of the corresponding battery pack to the main control unit. The main control unit can integrate the received status information of the battery pack into the status information of the battery cluster and report it to the control unit. The control unit can receive the status information of the battery cluster sent by each main control unit.

[0094] S130: For any one of the N branches, based on the status information of all battery clusters on the branch, send a power-on command to one of the battery clusters on the branch or to all M battery clusters on the branch that meet the voltage balance requirement. M is a positive integer greater than or equal to 2. Voltage balance means that the voltage value related to a certain battery cluster among the M is the reference voltage, and the difference between the internal sampled voltage of the remaining battery clusters among the M and the reference voltage is less than a first threshold. The power-on command is used to instruct the corresponding battery cluster to perform a power-on operation.

[0095] Based on the battery cluster status information reported by each main control unit, the control unit can obtain the internal sampled voltage of all battery clusters in any given branch. When the internal samples of any two battery clusters in a branch do not meet voltage balance, a power-on command is sent to one of the battery clusters in the branch. When the internal samples of M out of Q battery clusters in a branch meet voltage balance, a power-on command is sent to all M battery clusters, where 2 ≤ M ≤ Q. The first threshold is a voltage difference threshold characterizing the voltage difference between any two battery clusters when circulating current occurs. The value of the first threshold can be between 10V and 20V, and can be arbitrarily selected from 10V, 15V, and 20V.

[0096] Sending a power-on command to the battery cluster can refer to sending a power-on command to the main control unit of the battery cluster. Upon receiving the power-on command, the main control unit controls the corresponding battery cluster to perform a power-on operation. The power-on operation can refer to the process of connecting the battery cluster to the corresponding busbar so as to connect it to the high-voltage circuit through the corresponding energy storage converter.

[0097] Therefore, when the control method of this energy storage system is applied to an energy storage system with multiple branches, the control unit, in response to a power-on request, can control each branch to power on independently. This means that when each branch implements power-on control, it is not necessary to logically compare the voltage of the battery cluster in that branch with the voltage of the battery cluster in another branch; that is, the power-on logic of each branch is independent and does not affect each other. Furthermore, for any branch, if the voltages of M battery clusters are balanced, then power-on control of all M battery clusters is implemented; if the voltages of any two battery clusters are unbalanced, then power-on control of only one battery cluster is implemented. This ensures that at least one battery cluster in each branch is powered on, enabling all N branches to be powered on. Compared to related technologies where some branches cannot be powered on, this increases the external discharge capacity of the energy storage system. Simultaneously, it minimizes the possibility of circulating currents in branches damaging the battery clusters on those branches.

[0098] In S130, for any branch, it can be determined whether there are M battery clusters whose internal sampling satisfies voltage balance before all battery clusters on the branch have performed the power-on operation; alternatively, it can first determine the first battery cluster among the Q battery clusters, perform the power-on operation on the first battery cluster, take the voltage value related to the first battery cluster as the reference voltage, and then check whether there are battery clusters on the remaining battery clusters on the branch whose voltage is balanced with the first battery cluster. The two possible implementation methods are explained below.

[0099] In some possible implementations of this application, S130 can be implemented using the following steps.

[0100] Step 1: For any one of the N branches, obtain the status information of all battery clusters on the branch, and determine the highest and lowest internal sampling voltages.

[0101] The highest internal sampling voltage can refer to the highest value of the internal sampling voltage among all battery clusters, and the lowest internal sampling voltage can refer to the lowest value of the internal sampling voltage among all battery clusters.

[0102] Step 2: Using the highest internal sampling voltage and the lowest internal sampling voltage as the reference voltage, confirm whether the difference between the other of the highest and lowest internal sampling voltages and the reference voltage is less than the first threshold.

[0103] Step 3: If yes, confirm that the internal sampling voltage of all battery clusters on the branch is balanced, and send a power-on command to all battery clusters on the branch.

[0104] In steps 2 and 3, by comparing the highest and lowest internal sampling voltages, if the difference between the highest and lowest internal sampling voltages is less than a first threshold, then the difference between the internal sampling voltages of any two battery clusters is also less than the first threshold. Based on this, a power-on command is sent to all battery clusters. In this way, no circulating current will be generated between any two successfully powered-on battery clusters on the branch, thus reducing the possibility of circulating current damaging the battery clusters.

[0105] It can simultaneously send power-on commands to all battery clusters on a branch line, or it can send power-on commands to all battery clusters on a branch line in a sequential order.

[0106] Step 4: If not, send a power-on command to one of the battery clusters on the branch.

[0107] In some other possible implementations of this application, S130 can also be implemented using the following steps.

[0108] S131, For any one of the N branches, determine the first battery cluster among all battery clusters based on the state information of all battery clusters on the branch.

[0109] S132, send a power-on command to the first battery cluster.

[0110] This step can be understood as sending a power-on command to the main control unit of the first battery cluster. Upon receiving the power-on command, the main control unit of the first battery cluster controls the first battery cluster to perform the power-on operation.

[0111] S133, if the first battery cluster is successfully powered on, confirm whether there is a second battery cluster on the branch, the voltage of the second battery cluster is equal to that of the first battery cluster, and the reference voltage is related to the first battery cluster.

[0112] Successful power-on means that the main positive relay K+ and the main negative relay K- of the main circuit where the first battery cluster is located are closed, and the first battery cluster is connected to the corresponding bus. As described above, voltage equalization between the second and first battery clusters means that the voltage value related to the first battery cluster is taken as the reference voltage, and the difference between the internal sampling voltage of the second battery cluster and the reference voltage is less than the first threshold.

[0113] S134, in response to the presence of a second battery cluster on the branch, sends a power-on command to the second battery cluster.

[0114] When there are multiple second battery clusters, S134 can send power-on commands to multiple second battery clusters simultaneously, or it can send power-on commands to multiple second battery clusters sequentially in order (e.g., the order of the physical addresses of the multiple second battery clusters).

[0115] S135, in response to the absence of a second battery cluster on the branch, ends the power-on process.

[0116] S136, if the first battery cluster fails to power on, based on the status information of the remaining battery clusters on the branch, a new battery cluster is determined from the remaining battery clusters to replace the first battery cluster, and the process returns to S132.

[0117] As can be seen from the above, when executing step S132, only a single battery cluster on the branch is powered on, while other battery clusters are not powered on, so no circulating current is generated. When executing step S134, multiple battery clusters on the branch are powered on. Since the first battery cluster and the second battery cluster satisfy voltage balance, it means that no circulating current will be generated between the first battery cluster and the second battery cluster when they are powered on simultaneously.

[0118] Compared to the approach of confirming the voltage balance of M battery clusters on a branch before powering them on, this embodiment considers the power-on process for any branch as divided into two stages: single-cell power-on and multi-cell power-on. The multi-cell power-on stage is based on the successful power-on of the first battery cluster in the single-cell power-on stage. This ensures that no circulating current occurs during the single-cell power-on stage, and that no circulating current occurs between the first and second battery clusters during the multi-cell power-on stage, due to the voltage balance between them. This reduces the likelihood of circulating current between the first and second battery clusters, thus improving the operational stability of the energy storage system.

[0119] Optionally, S133 may specifically involve, upon successful power-up of the first battery cluster, acquiring a reference voltage, where the reference voltage is the internal sampling voltage of the first battery cluster; determining whether any of the other battery clusters on the branch has an internal sampling voltage whose difference from the reference voltage is less than a first threshold; and, based on the determination result, confirming the existence of a second battery cluster. In this embodiment, the internal sampling voltage of the first battery cluster is set as the reference voltage, and the internal sampling voltages of the first and second battery clusters are balanced, meaning the difference between the internal sampling voltage of the second battery cluster and the internal sampling voltage of the first battery cluster is less than the first threshold.

[0120] In some embodiments of this application, S133 can be replaced by the following steps.

[0121] S1331, if the first battery cluster is successfully powered on, acquire the reference voltage, which is the external sampling voltage of the first battery cluster.

[0122] In this embodiment, the status information also includes the external sampling voltage Vd. The external sampling voltage Vd refers to the potential difference between the second terminal of the main positive relay K+ (i.e., terminal A connected to the positive terminal of the energy storage converter) and the second terminal of the main negative relay K- (i.e., terminal B connected to the negative terminal of the energy storage converter) in the main circuit where the battery cluster is located. In other words, the main control unit can acquire not only the internal sampling voltage of the corresponding battery cluster but also the external sampling voltage of the corresponding battery cluster. It should be understood that when the main positive relay K+ and the main negative relay K- in the main circuit where the battery cluster is located are closed, the external sampling voltage Vd corresponding to that battery cluster can be acquired.

[0123] In this step, after the first battery cluster is successfully powered on, the main control unit of the first battery cluster acquires the external sampling voltage and reports it to the control unit. The control unit receives the external sampling voltage and uses it as a reference voltage.

[0124] S1332, determine whether, on the branch, among the other battery clusters, there exists a battery cluster whose internal sampling voltage and reference voltage have an absolute value less than a first threshold.

[0125] S1333, Based on the judgment result, confirm whether a second battery cluster exists.

[0126] S1332 and S1333 mean that the battery clusters on the branch that satisfy "|internal sampling voltage - reference voltage| < first threshold" are selected as the second battery clusters. That is, the second battery clusters must satisfy "|internal sampling voltage of the second battery cluster - external sampling voltage of the first battery cluster| < first threshold".

[0127] Compared to the reference voltage being the internal sampling voltage of the first battery cluster, and the internal sampling voltage of the second battery cluster being balanced with the internal sampling voltage of the first battery cluster, this embodiment uses the external sampling voltage of the first battery cluster that has been successfully powered on as the reference voltage. This means that the circuit voltage is normal when the first battery cluster is connected to the energy storage converter. By designing the second battery cluster to ensure that the absolute value of the difference between its internal sampling voltage and the reference voltage is less than a first threshold, the internal sampling voltage of the selected second battery cluster is balanced with the external sampling voltage of the first battery cluster that has been successfully powered on. This reduces the possibility of circulating current between the second battery cluster connected to the busbar and the first battery cluster, while also ensuring that the circuit voltage is normal when the second battery cluster is connected to the energy storage converter. This helps to reduce the risk of high voltage surge to the energy storage converter caused by excessive voltage difference between the second battery cluster and the energy storage converter.

[0128] In some examples, the first battery cluster can be the battery cluster corresponding to the highest internal sampling voltage or the battery cluster corresponding to the lowest internal sampling voltage.

[0129] In some examples, each branch has at least three battery clusters, i.e., Q≥3, and the first battery cluster can also be the battery cluster corresponding to the middle position of the internal sampled voltage sorting.

[0130] In this embodiment, determining the first battery cluster in S131 among all battery clusters can specifically be: determining the battery cluster whose internal sampling voltage is in the middle position among all battery clusters as the first battery cluster.

[0131] Compared to the first battery cluster being defined as either the battery cluster with the highest internal sampling voltage or the battery cluster with the lowest internal sampling voltage, this embodiment uses a method where the internal sampling voltage of the first battery cluster is arranged in the middle order. This allows either the battery cluster on the branch that satisfies "internal sampling voltage - reference voltage < first threshold" to be identified as the second battery cluster, or the battery cluster on the branch that satisfies "reference voltage - internal sampling voltage < first threshold" to be identified as the second battery cluster. In other words, under the premise of balancing the internal sampling voltage of the second battery cluster with that of the first battery cluster, the number of second battery clusters can be increased, so M is made as large as possible. This allows as many battery clusters on each branch as possible to perform power-on operations, enabling all N branches to be powered on. This also helps to increase the number of battery clusters connected to the energy storage converter on the branch, thereby improving the external discharge capacity of the energy storage system.

[0132] In some embodiments of this application, the status information may further include fault information. In this example, S130 specifically involves sending a power-on command to one of the battery clusters on the branch that meets the allowed power-on conditions, or to all M battery clusters on the branch that meet the allowed power-on conditions and have balanced voltages, based on the status information of all battery clusters on the branch, for any one of the N branches; wherein the allowed power-on conditions include a fault level lower than a first preset level.

[0133] In other words, the battery clusters that perform the power-on operation must meet the conditions for being allowed to power on, that is, the fault level of the battery clusters that perform the power-on operation should be lower than the first set level.

[0134] Based on this, in the embodiment where the specific implementation process of S130 is steps S131 to S136, both the first battery cluster and the second battery cluster must meet the conditions for being allowed to be powered on.

[0135] In this embodiment, by designing the system to send power-on commands to battery clusters that meet the permissible power-on conditions on the branch, the battery clusters that receive the power-on commands and perform the power-on operation must meet the prerequisites of meeting the permissible power-on conditions. This is beneficial for the battery clusters that receive the power-on commands to be able to power on normally, thus eliminating the need to send power-on commands to battery clusters that do not meet the permissible power-on conditions. This simplifies the control process of the energy storage system and also helps to reduce the adverse effects of faults on the energy storage system.

[0136] In the embodiment where S130 is specifically implemented as steps S131 to S136, in S131, battery clusters that meet the allowed power-on conditions can be selected first, and then the battery cluster in the middle of the sorting can be determined as the first battery cluster. Alternatively, the battery cluster in the middle of the sorting can be determined first, and then it can be determined whether the battery cluster meets the allowed power-on conditions. The two possible implementation methods are described below.

[0137] In some examples, the specific implementation process of S131 can be as follows: For any branch, based on the status information reported by the main control unit of all battery clusters, battery clusters that meet the allowed power-on conditions can be selected from all battery clusters (i.e., Q battery clusters) as the power-on group; then, the internal sampled voltages of the battery clusters that meet the allowed power-on conditions in the power-on group are sorted, and the battery cluster in the middle position of the sort is determined as the first battery cluster, and the voltage value related to the first battery cluster is taken as the reference voltage. Correspondingly, S1332 can be used to select the battery clusters that meet the condition "|internal sampled voltage - reference voltage| < first threshold" from the other battery clusters in the power-on group as the second battery cluster, then the second battery cluster also meets the allowed power-on conditions.

[0138] In other examples, the specific implementation process of S131 can also be as follows.

[0139] S1311: For any branch, first sort the internal sampled voltages of all battery clusters to determine the battery cluster in the middle of the sort.

[0140] S1312, based on the status information reported by the main control unit of the battery cluster, confirm whether the battery cluster in the middle position meets the conditions for being allowed to be powered on.

[0141] S1313, in response to the battery cluster in the middle position of the sequence meeting the allowed power-on conditions, the battery cluster is determined as the first battery cluster.

[0142] S1314, in response to the battery cluster in the middle position of the sorting not meeting the allowed power-on conditions, determine the battery cluster in the middle position of the sorting from the remaining battery clusters and return to S1312.

[0143] In this example, S1333 can be implemented using the following steps: if the judgment result is yes, based on the status information reported by the main control unit of the battery cluster, confirm whether the battery cluster that meets the condition of "|internal sampling voltage - reference voltage| < first threshold" meets the allowed power-on condition; if the allowed power-on condition is met, confirm the battery cluster as the second battery cluster.

[0144] The sorting method described above can be either ascending or descending order. Here, taking the example of sorting first and then determining whether the power-on condition is met, S1311 sorts the internal sampled voltages of the Q battery clusters on the branch. If Q is odd, the (Q+1) / 2th internal sampled voltage is sorted in the middle position; if Q is even, either the Q / 2th internal sampled voltage or the (Q / 2)+1th internal sampled voltage is sorted in the middle position.

[0145] There are various ways to determine whether a battery cluster meets the conditions for being allowed to power on based on its status information.

[0146] Optionally, the status information reported by the battery management unit to the main control unit includes fault information. The main control unit can synthesize the received battery pack status information into battery cluster status information and report it to the control unit. The control unit receives the battery cluster status information, including fault information. The control unit can determine the fault level of the battery cluster based on the fault information. If the fault level of the battery cluster is lower than the first preset level, the control unit confirms that the battery cluster meets the conditions for allowing power-on. It should be noted that the fault level of the battery cluster ranges from level 1 to level 7, with higher fault levels indicating more severe faults. The first preset level is a fault level threshold that characterizes the battery cluster's inability to power on, and can be selected based on experience and actual operating conditions; for example, it can be level 4.

[0147] In alternative methods, the status information reported by the battery management unit to the main control unit includes fault information. The main control unit can determine the fault level of the battery cluster based on the status information of the battery pack. In response to the fault level of the battery cluster being lower than the first set level (e.g., level 4), the power-on flag is switched from low level to high level, and status information including a power-on permission signal is reported to the control unit. The control unit receives the status information including the power-on permission signal and confirms that the battery cluster meets the power-on permission conditions based on the power-on permission signal.

[0148] In this embodiment, the main control unit does not need to analyze the fault information of the battery cluster to determine the fault level. It can determine that the battery cluster meets the power-on triggering conditions upon receiving a power-on permission signal. Therefore, the method for confirming whether the battery cluster meets the power-on triggering conditions is quick and simple, which is beneficial to improving the operating efficiency of the energy storage system.

[0149] In some embodiments of this application, during S130, while sending a power-on command to any battery cluster, the power-on duration of the battery cluster can also be timed; in response to the battery cluster completing the power-on operation within a first preset duration, the power-on of the battery cluster is confirmed to be successful; in response to the power-on operation not completing within the first preset duration, the power-on of the battery cluster is confirmed to be unsuccessful.

[0150] As can be seen from the preceding text, in the embodiment where S130 includes S131 to S136, S132 may be to send a power-on command to the first battery cluster while timing the power-on duration of the first battery cluster; in response to the first battery cluster completing the power-on operation within a first preset duration, the power-on of the first battery cluster is confirmed to be successful.

[0151] Power-on time refers to the time required for a battery cluster to connect to the bus and operate normally. For a properly functioning battery cluster, the power-on time is generally short. If the power-on time of a battery cluster is too long, it indicates that the cluster is not in a normal working state. Continuing to keep it powered on may lead to further malfunctions or even accidents. The first preset time is a pre-set threshold for the power-on time.

[0152] In this embodiment, a first preset duration is set as a threshold to determine whether the power-on time of the battery cluster is too long, so that the power-on time of the battery cluster that is successfully powered on does not exceed the first preset duration, thereby ensuring that the battery cluster that is successfully powered on functions normally. This can reduce the possibility of malfunctions or even accidents caused by powering on battery clusters that are not functioning normally.

[0153] In some embodiments of this application, the status information may include both internal and external sampling voltages. The power-on command can be configured to: instruct the pre-charging circuit of the corresponding battery cluster to be powered on, acquire the pre-charging duration, internal sampling voltage, and external sampling voltage of the battery cluster; instruct the corresponding battery cluster, based on the pre-charging duration, internal sampling voltage, and external sampling voltage, to confirm whether the absolute value of the potential difference between the internal and external sampling voltages of the battery cluster is less than a second threshold within a second preset duration of the pre-charging duration; and instruct the corresponding battery cluster to power on its main circuit and disconnect the pre-charging circuit in response to the absolute value of the potential difference between the internal and external sampling voltages of the battery cluster being less than the second threshold within the second preset duration of the pre-charging duration.

[0154] Optionally, the power-on command can be configured to indicate that if the absolute value of the potential difference between the internal sampling voltage and the external sampling voltage of the battery cluster is greater than or equal to a second threshold within a second preset time period in response to the pre-charge duration of the battery cluster, the battery cluster fails to power on.

[0155] In other words, as shown in Figure 6, the control method of the main control unit of the battery cluster after receiving the power-on command sent by the control unit includes the following steps S410 to S460.

[0156] S410, pre-charge circuit for battery clusters.

[0157] S420 acquires the precharge duration, internal sampling voltage, and external sampling voltage of the battery cluster.

[0158] S430, confirm whether the absolute value of the potential difference between the internal sampling voltage and the external sampling voltage of the battery cluster within the second preset time period is less than the second threshold; if yes, S440; if no, S460.

[0159] S440, the main circuit of the battery cluster is powered on, and the pre-charge circuit is disconnected.

[0160] S450, battery cluster successfully powered on.

[0161] S460, confirmed that the battery cluster failed to power on.

[0162] As mentioned earlier, the control unit sends a power-on command to the main control unit of the battery cluster, and the main control unit of the battery cluster responds to the power-on command. Specifically, the main control unit's response to the power-on command to power on the pre-charge circuit of the corresponding battery cluster can mean first controlling the main negative relay to close, and then controlling the pre-charge relay to close, thus enabling the pre-charge circuit to conduct.

[0163] Precharge duration refers to the time it takes for the charging circuit to be powered on. For a properly functioning battery cluster, a short precharge duration is sufficient to satisfy the condition that "|internal sampling voltage of the battery cluster - external sampling voltage of the battery cluster| < second threshold". If the condition is only satisfied when the precharge duration is excessively long, it indicates that the battery cluster is not in a normal operating state. Continuing to power it on may lead to further malfunctions or even accidents. The second preset duration is a threshold value pre-set for the precharge duration.

[0164] In this embodiment, the pre-charging circuit is energized before the main circuit is energized when the battery cluster is powered on. This helps to reduce the risk of high voltage surge to the energy storage converter caused by excessive voltage difference between the battery cluster and the energy storage converter.

[0165] Furthermore, this embodiment also uses a second preset duration as a threshold to determine whether the pre-charge time of the battery cluster is too long. This allows battery clusters with a pre-charge time within the second preset duration to continue powering on, thus reducing the possibility of malfunctions or even accidents caused by powering on battery clusters that are not functioning properly. The second preset duration can be reasonably designed based on experience and actual operating conditions, for example, it can be 100ms or 200ms.

[0166] In some embodiments, the main control unit responds to a power-on command by powering on the main circuit of the battery pack and disconnecting the pre-charge circuit. Specifically, this can mean first controlling the main positive relay to close, thus powering on the main circuit, and then, after a third preset time delay, controlling the pre-charge relay to open, thereby disconnecting the pre-charge circuit. The third preset time can be designed based on experience and requirements, for example, it can be 1000ms.

[0167] By designing a third preset time delay after the main circuit is powered on before cutting off the pre-charging circuit, the pre-charging circuit remains closed during the process of the main circuit connecting to the busbar to connect to the high-voltage circuit. This helps to further reduce the possibility of excessive voltage difference between the internal sampling voltage of the battery cluster and the voltage of the energy storage converter, which could cause high-voltage surges to the energy storage converter.

[0168] In some embodiments, the energy storage system can be confirmed to be powered on when at least one battery cluster in any of the N branches is successfully powered on. This ensures that all branches of the powered-on energy storage system are successfully powered on during operation, thereby improving the system's external discharge capacity and operational stability.

[0169] In some embodiments of this application, after S130, the control method of the energy storage system may further include the following steps.

[0170] S140, confirm whether the total number of battery clusters that have successfully powered on exceeds the minimum number of operating battery clusters.

[0171] The minimum number of operating battery clusters is preset, and the minimum number of operating battery clusters is ≤Q, for example, it can be 1, 2, 3, 4 or 5.

[0172] S150, in response to the total number of battery clusters that have successfully powered on exceeding the minimum number of operating battery clusters, confirms that the energy storage system has been powered on.

[0173] In this embodiment, the energy storage system is considered to have completed power-on when the total number of successfully powered-on battery clusters exceeds the minimum number of operating battery clusters. This ensures that when the energy storage system is running, the total number of successfully powered-on battery clusters is greater than or equal to the minimum number of operating battery clusters, thus meeting design and usage requirements.

[0174] In some embodiments of this application, the control method for the energy storage system may further include:

[0175] Before S110, obtain the status information of all battery clusters on N branches. The status information may also include fault information. Based on the fault information of all battery clusters, determine the fault level of each battery cluster. Confirm whether the total number of battery clusters with fault levels lower than the second set level is greater than or equal to the minimum number of operating battery clusters. In response to the total number of battery clusters with fault levels lower than the second set level being greater than or equal to the minimum number of operating battery clusters, execute S110.

[0176] As mentioned earlier, the fault levels of battery clusters range from level 1 to level 7, with higher levels indicating more severe faults. The second setting level is a threshold used to characterize whether a battery cluster has a fault level that affects its normal power-on. For example, the second setting level could be either level 6 or level 7. The second setting level is higher than the first setting level.

[0177] By adopting this design, the failure level of the battery clusters is determined, and the prerequisite for the energy storage system to respond to the power-on request is that the total number of battery clusters with failure levels below the second set level is greater than or equal to the minimum number of operating battery clusters. In other words, the number of battery clusters that can be powered on normally is not less than the minimum number of operating battery clusters. This reduces the possibility of battery clusters in a severely faulty state being powered on, and reduces the adverse effects of failures on the energy storage system, which helps to improve the safety of the energy storage system.

[0178] As shown in Figures 1 and 2, this application also proposes an energy storage system, which includes: N branches, at least one energy storage converter, and a control unit; each branch is provided with multiple battery clusters connected in parallel and independent of each other, each battery cluster including at least one battery pack, where N is a positive integer greater than or equal to 2; each energy storage converter is electrically connected to one branch or K branches connected in parallel, and the battery clusters of each branch can be charged or discharged through the corresponding energy storage converter, where K is a positive integer greater than or equal to 2 and less than or equal to N; the control unit is electrically connected to at least one energy storage converter, and the control unit is configured to implement the control method of the energy storage system of any of the above embodiments.

[0179] This application also proposes a computer device, which includes at least one memory and at least one processor communicatively connected to the at least one memory; the at least one memory stores instructions; and the at least one processor executes the instructions individually or collectively to implement the control method of the energy storage system of any of the above embodiments.

[0180] Various embodiments of the systems and technologies described above in this application can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include: implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0181] This application also proposes a computer-readable storage medium storing instructions that, when executed individually or jointly by one or more processors of a computer device, implement the control method of the energy storage system of any of the above embodiments.

[0182] Computer-readable media can be tangible media that may contain or store programs for use by or in conjunction with an instruction execution system, apparatus, or device. Machine-readable media can be machine-readable signal media or machine-readable storage media. Machine-readable media can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0183] This application also proposes a computer program product, including instructions that, when executed individually or jointly by one or more processors of a computer device, implement the control method of the energy storage system of any of the above embodiments.

[0184] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application.

[0185] In the embodiments of this application, as shown in Figures 1 and 2, the energy storage system includes N branches, at least one energy storage converter, and a control unit, where N is a positive integer greater than or equal to 2. Each branch has Q battery clusters connected in parallel and independent of each other, where Q is a positive integer greater than or equal to 3. Each battery cluster includes at least one battery pack and a main control unit for managing the operating status of at least one battery pack within the battery cluster. Each battery pack includes multiple battery cells and a battery management unit for managing the operating status of the multiple battery cells within the battery pack. The energy storage converter is electrically connected to the power-consuming equipment and the power generation equipment.

[0186] The control unit also communicates with the main control unit and the energy storage converter via a CAN bus. The main control unit communicates with the battery management unit via a CAN bus. The battery management unit reports the status information of the corresponding battery pack to the main control unit. The status information may include, but is not limited to, at least one of the following: internal sampled voltage, external sampled voltage, fault information, power-on permission signal, temperature, health status, etc. The main control unit then synthesizes and reports the status information of the battery pack reported by the battery management unit to the control unit.

[0187] As shown in Figure 7, the control method for the energy storage system includes the following steps. The main body executing the control method for this energy storage system is the control unit.

[0188] S210, obtain the status information of all battery clusters on N branches.

[0189] S220 determines the fault level of each battery cluster based on the fault information of all battery clusters.

[0190] S230, confirm whether the total number of battery clusters with fault levels below 6 is greater than or equal to the minimum number of operating battery clusters.

[0191] S240, in response to the total number of battery clusters with fault level below 6 being greater than or equal to the minimum number of operating battery clusters, obtains a power-on request.

[0192] S250, in response to a power-on request, obtains the status information of all battery clusters on each branch.

[0193] S260, for any one of the N branches, based on the status information of all battery clusters on the branch, sends a power-on command to one of the battery clusters on the branch or to all M battery clusters on the branch that meet the voltage balance requirement. M is a positive integer greater than or equal to 2. Voltage balance means that the voltage value related to a certain battery cluster among the M is the reference voltage, and the difference between the internal sampled voltage of the remaining battery clusters among the M and the reference voltage is less than a first threshold. The power-on command is used to instruct the corresponding battery cluster to perform a power-on operation.

[0194] S270, confirm whether the total number of battery clusters that have successfully powered on is greater than or equal to the minimum number of operating battery clusters.

[0195] S280, in response to the total number of battery clusters that have successfully powered on being greater than or equal to the minimum number of operating battery clusters, confirms that the energy storage system has been powered on and issues a request power command.

[0196] S290, in response to the total number of battery clusters that have successfully powered on being less than the minimum number of battery clusters that can be operated, issues a power-on failure command.

[0197] In step S260, the power-on process for any one of the N branches includes the following steps S31 to S44.

[0198] S31, based on the status information of all battery clusters on the branch, select the battery clusters that meet the allowable power-on conditions (the fault level of the battery cluster is lower than level 4) from all battery clusters as the power-on groups.

[0199] S32, the internal sampled voltages of each battery cluster in the energized group are sorted in ascending order, and the battery cluster whose internal sampled voltage is in the middle position in the energized group is determined as the first battery cluster. In this step, when the energized group has an odd number of battery clusters, the battery cluster whose internal sampled voltage is ranked at the (number of battery clusters / 2)th position is designated as the first battery cluster. When the energized group has an even number of battery clusters, the battery cluster whose internal sampled voltage is ranked at the (number of battery clusters / 2)+1th position is designated as the first battery cluster.

[0200] S33 sends a power-on command to the first battery cluster and simultaneously times the power-on duration of the first battery cluster.

[0201] S34, confirm whether the first battery cluster has completed the power-on operation within the first preset time period; if yes, proceed to S35; if no, proceed to S43.

[0202] S35, in response to the first battery cluster completing the power-on operation within a first preset time period, confirm that the first battery cluster has been successfully powered on.

[0203] S36, Obtain the external sampling voltage of the first battery cluster and set it as the reference voltage.

[0204] S37, confirm whether there are any battery clusters in the other battery clusters that can be powered on that satisfy the condition "|internal sampling voltage - reference voltage| < first threshold".

[0205] S38, if the judgment result is yes, the battery cluster in the power-on group that satisfies "|internal sampling voltage - reference voltage| < first threshold" is determined as the second battery cluster.

[0206] S39 sends a power-on command to the second battery cluster and simultaneously times the power-on duration of the second battery cluster.

[0207] S40, confirm whether the second battery cluster has completed the power-on operation within the first preset time period.

[0208] S41, in response to the second battery cluster completing the power-on operation within a first preset time period, confirm that the second battery cluster has been successfully powered on.

[0209] S42, in response to the second battery cluster failing to complete the power-on operation within the first preset time period, confirm that the second battery cluster has failed to power on.

[0210] S43, in response to the first battery cluster failing to complete the power-on operation within the first preset time period, confirming that the first battery cluster has failed to power on, proceed to S44.

[0211] S44, reorder the internal sampled voltages of the remaining battery clusters in the energized group, and determine the battery cluster in the middle position as the new first battery cluster, then return to S33.

[0212] In this article, sending a power-on command specifically refers to the control unit sending a power-on command to the main control unit of the battery cluster. The main control unit responds to the power-on command and controls the corresponding battery cluster to power on according to the control process shown in Figure 6.

[0213] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A control method for an energy storage system, wherein, The energy storage system includes N branches and at least one energy storage converter. Each branch is provided with multiple independent battery clusters. Each battery cluster includes at least one battery pack. N is a positive integer greater than or equal to 2. Each energy storage converter is electrically connected to K branches, and each branch can be charged or discharged through the corresponding energy storage converter. K is a positive integer. When K is greater than or equal to 2 and less than or equal to N, the K branches are connected in parallel. The control method includes: Obtain a power-on request; In response to the power-on request, the status information of all battery clusters on each branch is obtained, the status information including at least the internal sampled voltage; and For any one of the N branches, based on the status information of all the battery clusters on the branch, a power-on command is sent to one of the battery clusters on the branch or to all M battery clusters on the branch that meet the voltage balance requirement. M is a positive integer greater than or equal to 2. The voltage balance means that the voltage value related to a certain battery cluster among the M is used as the reference voltage, and the difference between the internal sampled voltage of the remaining battery clusters among the M and the reference voltage is less than a first threshold. The power-on command is used to instruct the corresponding battery cluster to perform a power-on operation.

2. The control method for the energy storage system according to claim 1, wherein, For any one of the N branches, based on the status information of all the battery clusters on the branch, a power-on command is sent to one of the battery clusters on the branch or to all M battery clusters on the branch that meet voltage equalization, including: For any one of the N branches, based on the state information of all the battery clusters on the branch, determine the first battery cluster among all the battery clusters; Send the power-on command to the first battery cluster; If the first battery cluster is successfully powered on, it is confirmed whether there is a second battery cluster on the branch, the voltage of the second battery cluster is equal to that of the first battery cluster, and the reference voltage is related to the first battery cluster; In response to the presence of the second battery cluster on the branch, the power-on command is sent to the second battery cluster.

3. The control method for the energy storage system according to claim 2, wherein, The status information also includes the external sampling voltage; If the first battery cluster is successfully powered on, the process involves confirming the presence of a second battery cluster on the branch, ensuring that the voltage of the second battery cluster is equal to that of the first battery cluster, and specifying that the reference voltage is related to the first battery cluster. Specifically, this includes: If the first battery cluster is successfully powered on, the reference voltage is obtained, and the reference voltage is the external sampling voltage of the first battery cluster; Determine whether, on the branch, among the remaining battery clusters, there exists a battery cluster whose internal sampling voltage and the reference voltage have an absolute value less than the first threshold. Based on the judgment result, it is confirmed whether the second battery cluster exists.

4. The control method for the energy storage system according to claim 2 or 3, wherein, Each of the aforementioned branches is provided with at least three battery clusters; The step of determining the first battery cluster among all the battery clusters specifically includes: The battery cluster whose internal sampled voltage is in the middle position among all the battery clusters is determined as the first battery cluster.

5. The control method for the energy storage system according to any one of claims 1-4, wherein, The status information also includes fault information; The power-on command is sent to one of the battery clusters on the branch that meets the allowed power-on conditions, or the power-on command is sent to all M battery clusters on the branch that meet the allowed power-on conditions and satisfy voltage equalization; wherein, the allowed power-on conditions include a fault level lower than a first preset level.

6. The control method for the energy storage system according to any one of claims 1-4, wherein, While sending the power-on command to any one of the battery clusters, the power-on duration of the battery cluster is timed. In response to the battery cluster completing the power-on operation within a first preset time period, the power-on of the battery cluster is confirmed to be successful.

7. The control method for the energy storage system according to any one of claims 1-4, wherein, The status information also includes the external sampling voltage; The power-on command is configured to instruct the pre-charging circuit of the corresponding battery cluster to be powered on, and to obtain the pre-charging duration, internal sampling voltage and external sampling voltage of the battery cluster; Used to indicate and confirm whether the absolute value of the potential difference between the internal sampling voltage and the external sampling voltage of the corresponding battery cluster is less than a second threshold within the second preset time period of the precharge duration. It is also used to indicate that, within a second preset time period, the absolute value of the potential difference between the internal sampling voltage and the external sampling voltage of the corresponding battery cluster is less than a second threshold, so that the main circuit of the battery cluster is powered on and the pre-charging circuit is disconnected.

8. The control method for the energy storage system according to any one of claims 1-7, wherein, After sending a power-on command to one of the battery clusters on the branch or to all M battery clusters on the branch that meet voltage equalization, based on the status information of all the battery clusters on the branch, the method further includes: Confirm that the total number of battery clusters that have successfully powered on is greater than or equal to the minimum number of operating battery clusters; When the total number of battery clusters that have successfully powered on is greater than or equal to the minimum number of operating battery clusters, the power-on of the energy storage system is confirmed to be complete.

9. The control method for an energy storage system according to any one of claims 1-8, wherein, Before obtaining the power-on request, the status information of all battery clusters on the N branches is obtained, and the status information also includes fault information; Based on the fault information of all the battery clusters, the fault level of each battery cluster is determined; Confirm whether the total number of battery clusters with a fault level lower than the second set level is greater than or equal to the minimum number of operating battery clusters. The power-on request is obtained in response to the fact that the total number of battery clusters with a fault level lower than the second set level is greater than or equal to the minimum number of operating battery clusters.

10. An energy storage system, wherein, include: There are N branches, each branch is provided with multiple battery clusters, and each battery cluster includes at least one battery pack, where N is a positive integer greater than or equal to 2; At least one energy storage converter, each of the energy storage converters being electrically connected to one of the branches or K branches connected in parallel, and the battery clusters of each branch being able to be charged or discharged through the corresponding energy storage converter, where K is a positive integer greater than or equal to 2 and less than or equal to N; as well as A control unit, electrically connected to the at least one energy storage converter, is configured to implement the control method for performing the energy storage system according to any one of claims 1-9.

11. A computer device, wherein, include: At least one memory, wherein the at least one memory stores instructions; as well as At least one processor communicatively connected to the at least one memory, wherein the at least one processor executes the instructions individually or jointly to implement the control method of the energy storage system as described in any one of claims 1-9.

12. A computer-readable storage medium, wherein, The computer-readable storage medium stores instructions that, when executed individually or jointly by one or more processors of a computer device, implement the control method for the energy storage system as described in any one of claims 1-9.

13. A computer program product, wherein, The instructions include, when executed individually or jointly by one or more processors of a computer device, implementing the control method for the energy storage system as described in any one of claims 1-9.

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