Energy storage system and control method thereof

Abstract

The present application relates to the field of energy storage technology, and specifically discloses an energy storage system and a control method thereof. The energy storage system includes multiple branches, and the control method of the energy storage system includes obtaining a power-on request; in response to the power-on request, obtaining the status information of all battery clusters on each branch, the status information at least including the internal sampled voltage; for any branch, based on the status information of all battery clusters on the branch, sending a power-on instruction to one of the battery clusters on the branch or to multiple battery clusters with balanced voltage on the branch, the power-on instruction is used to instruct the corresponding battery cluster to perform a power-on operation. Using the control method of the present invention, there is a battery cluster or multiple battery clusters with balanced voltage on each branch to perform the power-on process, so that all branches can be powered on. Compared with the related art where some branches cannot be powered on, the external discharge amount of the energy storage system can be increased. At the same time, this can reduce the possibility of circulating current on the branch and damaging the battery cluster on the branch.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to an energy storage system and a control method thereof. Background Art

[0002] The energy storage system stores excess electrical energy through media or equipment when there is an oversupply of energy, and releases the stored energy when there is a shortage of energy, thereby solving the problem of grid volatility and supply instability. When the energy storage system consists of multiple branches and each branch includes multiple battery clusters, when the difference in the internal sampled voltages of each battery cluster is large, in order to reduce the possibility of circulating currents between the battery clusters and damaging the battery clusters, some branches are not powered on, resulting in low external discharge power of the energy storage system. Summary of the invention

[0003] In view of the above problems, the present application provides an energy storage system and a control method thereof, which solves the problem that some branches are not powered on, resulting in low external discharge power of the energy storage system.

[0004] The first aspect of the present application provides 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 a plurality of independent battery clusters, the 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, and when K is greater than or equal to 2 and less than or equal to N, the K branches are connected in parallel;

[0005] The control method of the energy storage system includes:

[0006] Get power-on request;

[0007] In response to a power-on request, acquiring status information of all battery clusters on each branch, the status information at least including an internal sampled voltage; and

[0008] For any of the N branches, based on the status information of all battery clusters on the branch, a power-on instruction is sent to one of the battery clusters on the branch or to M battery clusters on the branch that meet voltage balance, where M is a positive integer greater than or equal to 2. Voltage balance means that the voltage value related to a battery cluster among the M is used as a reference voltage, and the difference between the internal sampled voltages of the remaining battery clusters among the M and the reference voltage is less than a first threshold value. The power-on instruction is used to instruct the corresponding battery cluster to perform a power-on operation.

[0009] In the present application, in response to a power-on request, each branch independently performs a power-on process, and the power-on logic of each branch does not affect each other. And for any branch, when there are M battery clusters with balanced voltages, the power-on control of the M battery clusters is implemented, and when the voltages of any two battery clusters are unbalanced, the power-on control of a certain battery cluster is implemented. In this way, there is at least one battery cluster on each branch for power-on operation, so that N branches can all be powered on. Compared with the related art where some branches cannot be powered on, this can increase the external discharge amount of the energy storage system. At the same time, the possibility of generating circulating current on the branch and damaging the battery cluster on the branch is reduced as much as possible.

[0010] In some embodiments of the present application, for any branch of the N branches, based on the status information of all battery clusters on the branch, a power-on instruction is sent to a battery cluster on the branch or to all M battery clusters on the branch that meet voltage balance, including:

[0011] For any branch among the N branches, based on the status information of all the battery clusters on the branch, determine a first battery cluster among all the battery clusters;

[0012] Sending a power-on instruction to the first battery cluster;

[0013] When the first battery cluster is powered on successfully, confirm whether there is a second battery cluster on the branch line, the voltage of the second battery cluster is balanced with the first battery cluster, and the reference voltage is related to the first battery cluster;

[0014] In response to the second battery cluster being present on the branch line, a power-on instruction is sent to the second battery cluster.

[0015] In this embodiment, a single battery cluster (i.e., the first battery cluster) is first powered on on each branch, so that no circulating current is generated during the power-on phase of the single battery cluster. When the first battery cluster is successfully powered on, during the power-on phase of the second battery cluster, since the voltages of the first battery cluster and the second battery cluster are balanced, the possibility of generating circulating current between the first battery cluster and the second battery cluster is low, which is beneficial to improving the operational stability of the energy storage system.

[0016] In some embodiments of the present application, the state information further includes an external sampled voltage;

[0017] When the first battery cluster is powered on successfully, confirm whether there is a second battery cluster on the branch, the voltage of the second battery cluster is balanced with the voltage of the first battery cluster, and the reference voltage is related to the first battery cluster, specifically including:

[0018] When the first battery cluster is powered on successfully, obtaining a reference voltage, where the reference voltage is an external sampling voltage of the first battery cluster;

[0019] Determine whether, among the remaining battery clusters on the branch, there is a battery cluster whose absolute value of the difference between the internal sampling voltage and the reference voltage is less than a first threshold;

[0020] Based on the determination result, it is confirmed whether the second battery cluster exists.

[0021] By designing the second battery cluster to meet the requirement 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 the first threshold, the internal sampling voltage of the screened second battery cluster is balanced with the external sampling voltage of the first battery cluster that is successfully powered on. This can more accurately reduce the risk of high voltage shock to the energy storage inverter due to excessive voltage difference between the second battery cluster and the energy storage inverter.

[0022] In some embodiments of the present application, each branch is provided with at least three battery clusters;

[0023] Determining a first battery cluster among all battery clusters specifically includes:

[0024] A battery cluster whose internal sampled voltage is ranked in the middle among all the battery clusters is determined as the first battery cluster.

[0025] Designing the first battery cluster as a battery cluster whose internal sampling voltage is ranked in the middle position can increase the number of second battery clusters, which is beneficial to increase the number of battery clusters that perform power-on operations on the branches, which is beneficial to increase the possibility of powering on each branch and to increase the external discharge capacity of the energy storage system.

[0026] In some embodiments of the present application, the status information also includes fault information;

[0027] The specific method of sending a power-on instruction to one of the battery clusters on the branch or to all the M battery clusters on the branch that meet the voltage balance requirement is as follows:

[0028] A power-on instruction is sent to one of the battery clusters on the branch that meets the power-on condition, or a power-on instruction is sent to all M battery clusters on the branch that meet the power-on condition and have balanced voltage; wherein the power-on condition includes that the fault level is lower than the first set level.

[0029] By designing a system that sends power-on instructions to battery clusters on the branch that meet the power-on conditions, the battery cluster that receives the power-on instruction to perform the power-on operation should have the prerequisite of meeting the power-on conditions. In this way, there is no need to send power-on instructions to battery clusters that do not meet the power-on conditions, which is conducive to simplifying the control process of the energy storage system.

[0030] In some embodiments of the present application, while sending a power-on instruction to any battery cluster, the power-on duration of the battery cluster is timed;

[0031] In response to the battery cluster completing the power-on operation within the first preset time period, it is confirmed that the battery cluster is powered on successfully.

[0032] By setting the first preset time as a threshold to confirm whether the power-on time of the battery cluster is too long, the power-on time of the battery cluster that is successfully powered on does not exceed the first preset time, and the battery cluster that is successfully powered on functions normally, which can reduce the possibility of malfunction or even accident caused by powering on a battery cluster that is not functioning normally.

[0033] In some embodiments of the present application, the state information further includes an external sampled voltage;

[0034] The power-on instruction is configured to instruct the corresponding battery cluster to power on the pre-charging circuit, and obtain the pre-charging time, internal sampling voltage and external sampling voltage of the battery cluster;

[0035] 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 within the second preset time period is less than a second threshold value;

[0036] It is also used to indicate that within the second preset pre-charging time, 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 the second threshold value, so that the main circuit of the battery cluster is powered on and the pre-charging circuit is disconnected.

[0037] This embodiment is designed such that the battery cluster is powered on to the pre-charge circuit for pre-charging before the main circuit is powered on, which helps to reduce the risk of high voltage shock to the energy storage converter caused by excessive voltage difference between the battery cluster and the energy storage converter.

[0038] In some embodiments of the present application, after sending a power-on instruction to a battery cluster on the branch or to all M battery clusters with balanced voltage on the branch based on the status information of all battery clusters on the branch for any branch among the N branches, the method further includes:

[0039] Confirm whether the total number of battery clusters that are successfully powered on is greater than or equal to the minimum number of running battery clusters;

[0040] In response to the total number of battery clusters that are successfully powered on being greater than or equal to the minimum number of operating battery clusters, it is confirmed that the power-on of the energy storage system is completed.

[0041] With this arrangement, when the energy storage system that has been powered on is in operation, the total number of battery clusters that have been successfully powered on is greater than or equal to the minimum number of operating battery clusters, so as to meet design requirements and usage requirements.

[0042] In some embodiments of the present application, 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;

[0043] Based on the fault information of all battery clusters, determine the fault level of each battery cluster;

[0044] confirming 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;

[0045] In response to the total number of battery clusters having a fault level lower than a second set level being greater than or equal to the minimum number of operating battery clusters, a power-on request is acquired.

[0046] In this embodiment, the prerequisite for the energy storage system to respond to the power-on request is that 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. This can reduce the possibility of powering on a battery cluster in a serious fault state, which is beneficial to improving the safety of the energy storage system.

[0047] The second aspect of the present application proposes an energy storage system, comprising: N branches, at least one energy storage inverter and a control unit; each branch is provided with multiple battery clusters, the battery cluster includes at least one battery group, N is a positive integer greater than or equal to 2; each energy storage inverter is electrically connected to a branch or K branches connected in parallel, and the battery cluster of each branch can be charged or discharged through the corresponding energy storage inverter, 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 inverter, and the control unit is configured to implement a control method for any energy storage system proposed in the first aspect of the present application.

[0048] The third aspect of the present application 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 any one of the energy storage system control methods proposed in the first aspect of the present application.

[0049] The fourth aspect of the present application proposes a computer-readable storage medium, on which instructions are stored. When the instructions are executed individually or collectively by one or more processors of a computer device, any energy storage system control method proposed in the first aspect of the present application is implemented.

[0050] The fifth aspect of the present application proposes a computer program product, comprising instructions, which, when executed individually or collectively by one or more processors of a computer device, implement any of the energy storage system control methods proposed in the first aspect of the present application.

[0051] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 The module diagram of the energy storage system according to one embodiment of the present application is schematically shown;

[0053] Figure 2 The following schematically shows a block diagram of a composition of an energy storage system according to an embodiment of the present application;

[0054] Figure 3 A schematic diagram of an energy storage system according to an embodiment of the present application is schematically shown;

[0055] Figure 4 A schematic diagram of an energy storage system according to another embodiment of the present application is schematically shown;

[0056] Figure 5 A schematic diagram of a control method for an energy storage system according to an embodiment of the present application is schematically shown;

[0057] Figure 6 A schematic diagram of a process flow of a main control unit of an energy storage system responding to a power-on instruction according to an embodiment of the present application is schematically shown;

[0058] Figure 7 A flow chart of a control method for an energy storage system according to another embodiment of the present application is schematically shown. DETAILED DESCRIPTION

[0059] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0060] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0061] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0062] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0063] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0064] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0065] The energy storage system may include an energy storage converter and a plurality of 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 electrically connected battery cell. When the battery pack includes a plurality of (two or more) battery cells, the plurality of battery cells may be electrically connected in parallel and / or in series.

[0066] In some related technologies, one energy storage converter of the energy storage system corresponds to all battery clusters.

[0067] It is understandable that when the voltages of the battery clusters are different, a large circulating current is formed between the two battery clusters with a large voltage difference, and the circulating current impacts the battery cluster and easily causes damage to the battery cluster. In order to reduce the possibility of battery clusters being damaged by the circulating current, in the existing control method of energy storage system, the voltage of one battery cluster is often taken as the reference voltage, and the remaining battery clusters with a smaller difference between the voltage and the reference voltage are powered on.

[0068] However, one energy storage inverter corresponds to the energy storage system of all battery clusters. When all battery clusters are powered on, the current is large. Therefore, the protection devices in the energy storage system (for example, fuses for short-circuit protection and circuit breakers for power-off protection) need to be selected with high rated current models, which leads to high requirements for protection devices and great difficulty in selection.

[0069] In order to solve the above problems, the related art also proposes an energy storage system composed of multiple branches, each branch is provided with multiple battery clusters in parallel. Compared with all battery clusters connected in parallel, by providing multiple branches, the number of battery clusters in each branch is relatively reduced, which is conducive to reducing the requirements for protection devices, thereby reducing the difficulty of selecting protection devices. When the existing control method is applied to the energy storage system composed of multiple branches, for the branches where the difference between the voltage of each battery cluster and the reference voltage is large, the branch will not be powered on, resulting in a low external discharge of the energy storage system. Therefore, for the energy storage system composed of multiple branches, it is urgent to improve the control method of the energy storage system.

[0070] In this application, an energy storage system and its control method are designed. When a power-on request is obtained, each branch can be independently controlled to perform the power-on process, so that the power-on logic of each branch does not affect each other. And for any branch, a battery cluster or multiple battery clusters with balanced voltage on the branch are powered on. In this way, all branches can be powered on under the premise of reducing the possibility of circulating current in each branch, which can increase the external discharge capacity of the energy storage system.

[0071] The energy storage system disclosed in the embodiments of the present application can be applied in an electric power system, and the energy storage system disclosed in the present application can be used as an energy supplement for the electric power system.

[0072] The energy storage system disclosed in the embodiments of the present application can also be applied to an electrical device, and the power supply system of the electrical device can be composed of the energy storage system disclosed in the present application. The electrical device can be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, and the like. Among them, the electric toy can include a fixed or mobile electric toy, for example, a game console, an electric car toy, an electric ship toy, and an electric airplane toy, and the like, and the spacecraft can include an airplane, a rocket, a space shuttle, and a spacecraft, and the like.

[0073] For the convenience of description, the following embodiments take the power system of one embodiment of the present application as an example.

[0074] Please combine Figure 1 and Figure 2 As shown, the 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 Figure 1 The two shown in the figure can be customized according to actual working conditions.

[0075] Each branch is provided with Q battery clusters connected in parallel and independent of each other, where Q is also a positive integer greater than or equal to 2. The number of battery clusters in each branch may be the same or different. Each battery cluster may be installed in an independent electrical cabinet to protect the battery cluster from the external environment. The battery cluster may include at least one battery pack, that is, the battery cluster may include one or multiple battery packs connected in series. The battery cluster may also include a main control unit (BCMU) for managing the operating status of at least one battery pack in the battery cluster. Each battery pack may include a plurality of battery cells electrically connected in parallel and / or in series, and each battery pack may also include a battery management unit (Battery Management Unit, referred to as BMU) for managing the operating status of multiple battery cells in the battery pack.

[0076] The energy storage system may also include N buses corresponding to the N branches one by one, and the positive and negative electrodes 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 bus. Figure 3 and Figure 4 As shown, a main positive relay K+ may be provided between the positive electrode of each battery cluster and the corresponding energy storage converter, and a main negative relay K- may be provided between the negative electrode of each battery cluster and the energy storage converter. The battery cluster, the main positive relay K+, the main negative relay K- and the energy storage converter are connected in series to form a main circuit. The main positive relay K+ may also be connected in parallel with a pre-charging circuit, which includes a pre-charging relay S and a pre-charging resistor R connected in series.

[0077] Each energy storage converter is electrically connected to K branches, so that the battery cluster of each branch can be charged or discharged through the 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. It can be understood that there can be one energy storage converter, and then one energy storage converter is electrically connected to N branches.

[0078] There may also be multiple energy storage converters, and the number of branches corresponding to each energy storage converter may be the same or different. In one mode of this embodiment, the number of energy storage converters may be consistent with the number of branches, that is, the number of energy storage converters is also N, and the N energy storage converters correspond one to one to the N branches. In an embodiment where N ≥ 3 and the number of energy storage converters is not less than two, some of the energy storage converters may be connected to one branch, and the remaining energy storage converters may be connected to multiple branches of the N branches.

[0079] The energy storage inverter is electrically connected to the power-consuming equipment and the power generation equipment. The energy storage inverter can charge or discharge the battery cluster. Specifically, the power generation equipment charges the battery cluster of the corresponding branch through the energy storage inverter, and the multiple battery clusters on the branch supply power to the power-consuming equipment through the corresponding energy storage inverter. The energy storage inverter can also perform AC / DC conversion, and can directly supply power to AC loads in the absence of a power grid, and can adjust the active power and reactive power of the power grid.

[0080] The control unit is used to manage and control the operating status of at least one energy storage converter and all battery clusters on each branch included in the energy storage system.

[0081] The control unit can be configured to have communication capabilities. The control unit can, but is not limited to, communicate with at least one energy storage inverter and the main control unit (BCMU) of each battery cluster through 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 is connected to the main control unit (BCMU) of each battery cluster through 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, error frames, etc.) to the CAN bus, and can also receive the entire message when the required message is monitored and identified, so that the control unit and each main control unit can communicate. The main control unit (BCMU) can also be connected to each battery management unit (BMU) in the corresponding battery cluster through the CAN bus, so that the main control unit and the corresponding battery management units can communicate with each other as nodes on the CAN bus.

[0082] The control unit can also be configured to have parameter configuration function, which can not only modify its own parameters, but also modify the control parameters by issuing commands through CAN bus. The control unit can also realize the communication function with the background monitoring system, upload system information in real time and accept monitoring instructions from the monitoring background.

[0083] Among them, the control unit, the main control unit and the battery management unit can together constitute at least part of a battery management system (BMS). The battery management system is used to monitor the battery status and can also be used to connect with external devices.

[0084] 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 energy management system is used for energy scheduling.

[0085] The embodiment of the present application provides a control method for an energy storage system. The control method can be executed by a control unit of the energy storage system, that is, the execution subject of the control method is the control unit, and the function of the control unit is to control the operating status of at least one energy storage converter and all battery clusters on each branch included in the energy storage system.

[0086] Figure 5 The flowchart of the control method of the energy storage system according to one embodiment of the present application is schematically shown. Figure 5 As shown, the control method mainly includes the following steps.

[0087] S110, obtaining a power-on request.

[0088] The power-on request may be sent by the energy storage converter or an external device. In an embodiment where the energy storage system further includes an energy management system, the power-on request may be sent by the energy storage converter or an external device, or may be sent by the energy management system.

[0089] S120 , in response to the power-on request, obtaining status information of all battery clusters on each branch, where the status information at least includes an internal sampled voltage Va.

[0090] like Figure 3 and Figure 4 As shown, the internal sampling voltage Va refers to the potential difference between the positive electrode and the negative electrode when the main circuit corresponding to the battery cluster is in an open circuit state (the main positive relay and the main negative relay are not closed), which can also be understood as the potential difference between the first end of the main positive relay (i.e., the a end connected to the positive electrode of the battery cluster) and the first end of the main negative relay (i.e., the b end connected to the negative electrode of the battery cluster). When the battery cluster includes multiple battery packs connected in series, the internal sampling voltage Va can be understood as the sum of the voltage values ​​of the multiple battery packs 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 end of the main positive relay and the first end of the main negative relay when the main circuit corresponding to the battery cluster is in an open circuit state, the corresponding internal sampling voltage Va can be collected when the battery cluster is not powered on.

[0091] Based on the above content, it can be seen that 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 battery pack status information into battery cluster status information and report it to the control unit, and the control unit can receive the battery cluster status information sent by each main control unit.

[0092] S130, for any one of the N branches, based on the status information of all the battery clusters on the branch, a power-on instruction is sent to one of the battery clusters on the branch or to M battery clusters on the branch that meet voltage balance, where M is a positive integer greater than or equal to 2, and voltage balance means that the voltage value related to a battery cluster among the M is used as a reference voltage, and the difference between the internal sampled voltages of the remaining battery clusters among the M and the reference voltage is less than a first threshold value, and the power-on instruction is used to instruct the corresponding battery cluster to perform a power-on operation.

[0093] Based on the status information of the battery cluster reported by each main control unit, the control unit can obtain the internal sampling voltage of all battery clusters on any branch. In response to the internal sampling of any two battery clusters on the branch not satisfying the voltage balance, a power-on instruction is sent to a battery cluster on the branch. In response to the internal sampling of M battery clusters among the Q battery clusters on the branch satisfying the voltage balance, a power-on instruction is sent to all M battery clusters, 2≤M≤Q. Among them, the first threshold is the voltage difference threshold that characterizes the circulation current generated between any two battery clusters among the multiple battery clusters. The value range of the first threshold can be between 10V and 20V, and the first threshold can be selected from 10V, 15V and 20V.

[0094] Among them, sending a power-on instruction to the battery cluster may refer to sending a power-on instruction to the main control unit of the battery cluster. The main control unit receives the power-on instruction and controls the corresponding battery cluster to perform a power-on operation. The power-on operation may refer to the process of connecting the battery cluster to the corresponding bus to connect it to the high-voltage circuit through the corresponding energy storage inverter.

[0095] Therefore, when the control method of the energy storage system of the present application is applied to an energy storage system with multiple branches, the control unit can control each branch to be powered on independently in response to the power-on request, so that when each branch implements the power-on control, it is not necessary to logically compare and judge the voltage of the battery cluster of the branch with the voltage of the battery cluster on another branch, that is, the power-on logic of each branch does not interfere with or affect each other. In addition, for any branch, when the voltages of M battery clusters are balanced, the power-on control of M battery clusters is implemented, and when the voltages of any two battery clusters are unbalanced, the power-on control of a certain battery cluster is implemented. In this way, at least one battery cluster is available on each branch for power-on operation, so that N branches can all be powered on. Compared with the related art in which some branches cannot be powered on, this can increase the external discharge capacity of the energy storage system. At the same time, the possibility of generating circulating current on the branch and damaging the battery cluster on the branch is reduced as much as possible.

[0096] In S130, for any branch, before all battery clusters on the branch perform the power-on operation, it can be confirmed whether there are M battery clusters whose internal sampling satisfies voltage balance; or the first battery cluster can be determined among the Q battery clusters, so that the first battery cluster performs the power-on operation first, and the voltage value related to the first battery cluster is taken as the reference voltage, and then it is confirmed among the remaining battery clusters on the branch whether there are battery clusters whose voltage is balanced with the first battery cluster. Two possible implementation methods are described below.

[0097] In some possible implementations of the present application, S130 may be implemented using the following steps.

[0098] Step 1: For any branch among the N branches, obtain the status information of all battery clusters on the branch, and determine the highest internal sampling voltage and the lowest internal sampling voltage.

[0099] The highest internal sampling voltage may refer to the highest value of the internal sampling voltages in all battery clusters, and the lowest internal sampling voltage may refer to the lowest value of the internal sampling voltages in all battery clusters.

[0100] Step 2: using one of the highest internal sampling voltage and the lowest internal sampling voltage as a reference voltage, and confirming whether a difference between the other of the highest internal sampling voltage and the lowest internal sampling voltage and the reference voltage is less than a first threshold.

[0101] Step 3: If yes, confirm that the internal sampled voltages of all battery clusters on the branch are balanced, and send power-on instructions to all battery clusters on the branch.

[0102] In step 2 and step 3, by comparing the highest internal sampling voltage and the lowest internal sampling voltage, when the difference between the highest internal sampling voltage and the lowest internal sampling voltage is less than the first threshold, the difference between the internal sampling voltages of any two battery clusters is less than the first threshold. On this basis, a power-on instruction is sent to all battery clusters, so that no circulating current will be generated between any two battery clusters that are successfully powered on in the branch, which can reduce the possibility of circulating current damaging the battery cluster.

[0103] The power-on instruction may be issued to all battery clusters on the branch at the same time, or may be issued to all battery clusters on the branch in sequence.

[0104] Step 4: If not, send a power-on command to one of the battery clusters on the branch.

[0105] In some other possible implementations of the present application, S130 may also be implemented by using the following steps.

[0106] S131 : for any branch among the N branches, determine a first battery cluster among all the battery clusters based on the status information of all the battery clusters on the branch.

[0107] S132: Send a power-on instruction to the first battery cluster.

[0108] This step can be understood as sending a power-on instruction to the main control unit of the first battery cluster. The main control unit of the first battery cluster receives the power-on instruction and controls the first battery cluster to perform a power-on operation.

[0109] S133, when the first battery cluster is powered on successfully, confirm whether there is a second battery cluster on the branch line, the voltage of the second battery cluster is balanced with the first battery cluster, and the reference voltage is related to the first battery cluster.

[0110] 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. According to the above description, voltage balancing between the second battery cluster and the first battery cluster means taking the voltage value related to the first battery cluster 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.

[0111] S134: In response to the presence of the second battery cluster on the branch line, a power-on instruction is sent to the second battery cluster.

[0112] When there are multiple second battery clusters, in S134 , the power-on instructions may be sent to the multiple second battery clusters simultaneously, or may be sent to the multiple second battery clusters in sequence (eg, the order of the size of the physical addresses of the multiple second battery clusters).

[0113] S135 , in response to the absence of the second battery cluster on the branch line, ending the power-on process.

[0114] S136, when the first battery cluster fails to be powered 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.

[0115] From the above content, it can be seen that when executing step S132, only a single battery cluster on the branch performs the power-on operation, and other battery clusters are not powered on at this time, so no circulating current will be generated. When executing step S134, there are multiple battery clusters on the branch to be powered on. Since the first battery cluster and the second battery cluster meet voltage balance, it means that when the first battery cluster and the second battery cluster are powered on at the same time, no circulating current will be generated between the two.

[0116] Compared with the method of making the M battery clusters perform power-on operation after confirming that the voltage of the M battery clusters on the branch is balanced, in this embodiment, the power-on process for any branch can be regarded as divided into two stages: single battery cluster power-on and multi-battery cluster power-on, and the multi-battery cluster power-on stage is based on the single battery cluster power-on stage and the successful power-on of the first battery cluster. In this way, a single battery cluster (i.e., the first battery cluster) is firstly made to perform power-on operation on each branch, so that no circulating current will be generated in the single battery cluster power-on stage; in the multi-battery cluster power-on stage, since the voltage of the first battery cluster and the second battery cluster are balanced, the possibility of generating circulating current between the first battery cluster and the second battery cluster is low, which is conducive to improving the operation stability of the energy storage system.

[0117] Optionally, S133 may specifically include obtaining a reference voltage when the first battery cluster is powered on successfully, the reference voltage being the internal sampling voltage of the first battery cluster; determining whether there is a battery cluster in the remaining battery clusters on the branch whose difference between the internal sampling voltage and the reference voltage is less than a first threshold; and confirming whether there is a second battery cluster based on the determination result. 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 battery cluster and the second battery cluster are balanced, that is, 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.

[0118] In some embodiments of the present application, S133 may be replaced by the following steps.

[0119] S1331, when the first battery cluster is powered on successfully, obtaining a reference voltage, where the reference voltage is an external sampling voltage of the first battery cluster.

[0120] In this embodiment, the state information also includes an external sampling voltage Vd, which refers to the potential difference between the second end of the main positive relay K+ of the main circuit where the battery cluster is located (i.e., the A end connected to the positive end of the energy storage converter) and the second end of the main negative relay K- of the main circuit where the battery cluster is located (i.e., the B end connected to the negative end of the energy storage converter). In other words, in addition to being able to obtain the internal sampling voltage of the corresponding battery cluster, the main control unit can also obtain 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- of the main circuit where the battery cluster is located are closed, the external sampling voltage Vd corresponding to the battery cluster can be collected.

[0121] In this step, after the first battery cluster is powered on successfully, the main control unit of the first battery cluster obtains the external sampled voltage and reports it to the control unit, and the control unit receives the external sampled voltage and uses it as a reference voltage.

[0122] S1332, determining whether there is a battery cluster among the remaining battery clusters on the branch line whose absolute value of the difference between the internal sampling voltage and the reference voltage is smaller than a first threshold.

[0123] S1333: Based on the determination result, confirm whether a second battery cluster exists.

[0124] The meaning of S1332 and S1333 is to select the battery cluster that satisfies “|internal sampling voltage - reference voltage| < first threshold value” on the branch as the second battery cluster, that is, the second battery cluster must satisfy “|internal sampling voltage of the second battery cluster - external sampling voltage of the first battery cluster| < first threshold value”.

[0125] Compared with the internal sampling voltage of the first battery cluster, which is the reference voltage, the internal sampling voltage of the second battery cluster is balanced with the internal sampling voltage of the first battery cluster. In this embodiment, the external sampling voltage of the first battery cluster that is successfully powered on is used as the reference voltage, which means that the voltage of the circuit is normal when the first battery cluster is connected to the energy storage inverter. By designing the second battery cluster to meet the absolute value of the difference between its internal sampling voltage and the reference voltage being less than the first threshold, the internal sampling voltage of the screened second battery cluster is balanced with the external sampling voltage of the first battery cluster that is successfully powered on. In this way, the possibility of circulating current between the second battery cluster connected to the bus and the first battery cluster is low, and the voltage of the circuit is normal when the second battery cluster is connected to the energy storage inverter, which is beneficial to reduce the risk of high voltage shock to the energy storage inverter caused by excessive voltage difference between the second battery cluster and the energy storage inverter.

[0126] In some examples, the first battery cluster may be a battery cluster corresponding to the highest internal sampling voltage or a battery cluster corresponding to the lowest internal sampling voltage.

[0127] In some examples, each branch is provided with at least three battery clusters, that is, Q≥3, and the first battery cluster may also be a battery cluster corresponding to a middle position in the internal sampling voltage sorting.

[0128] In this embodiment, determining the first battery cluster among all the battery clusters in S131 may specifically be: determining the battery cluster whose internal sampled voltage is ranked in the middle among all the battery clusters as the first battery cluster.

[0129] Compared with the first battery cluster being the battery cluster corresponding to the highest internal sampling voltage / the battery cluster corresponding to the lowest internal sampling voltage, this embodiment adopts this method, and the internal sampling voltage of the first battery cluster is arranged in the middle position, so that the battery cluster on the branch that meets the "internal sampling voltage-reference voltage < first threshold" can be determined as the second battery cluster, and the battery cluster on the branch that meets the "reference voltage-internal sampling voltage < first threshold" can also be determined as the second battery cluster. In other words, under the premise of balancing the internal sampling voltage of the second battery cluster and the internal sampling voltage of the first battery cluster, the number of second battery clusters can be increased, and M is as large as possible, so that as many battery clusters as possible on each branch perform the power-on operation, so that N branches can all be powered on, which is conducive to increasing the number of battery clusters connected to the energy storage converter on the branch, so as to increase the external discharge capacity of the energy storage system.

[0130] In some embodiments of the present application, the status information may further include fault information. In this example, S130 specifically sends a power-on instruction to any of the N branches based on the status information of all battery clusters on the branch, to one of the battery clusters on the branch that meets the power-on condition or to all the M battery clusters on the branch that meet the power-on condition and have balanced voltage; wherein the power-on condition includes that the fault level is lower than the first set level.

[0131] That is, the battery cluster that performs the power-on operation needs to meet the power-on permission condition, that is, the fault level of the battery cluster that performs the power-on operation should be lower than the first set level.

[0132] 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 need to meet the power-on permission condition.

[0133] In this embodiment, a power-on instruction is sent to the battery cluster on the branch that meets the power-on permission condition, so that the battery cluster that receives the power-on instruction to perform the power-on operation should have the prerequisite of meeting the power-on permission condition, which is conducive to enabling the battery cluster that receives the power-on instruction to power on normally. In this way, there is no need to send a power-on instruction to the battery cluster that does not meet the power-on permission condition, which is conducive to simplifying the control process of the energy storage system and reducing the adverse effects of faults on the energy storage system.

[0134] In the embodiment where the specific implementation process of S130 is steps S131 to S136, in S131, the battery clusters that meet the power-on permission condition may be first screened out, and then the battery cluster in the middle of the sorting may be determined as the first battery cluster, or the battery cluster in the middle of the sorting may be first determined, and then it is determined whether the battery cluster meets the power-on permission condition. Two possible implementation methods are described below.

[0135] In some examples, the specific implementation process of S131 may be: for any branch, based on the status information reported by the main control units of all battery clusters, the battery clusters that meet the power-on condition 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 power-on condition in the power-on group are sorted, and the battery cluster in the middle position 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 select the battery clusters that meet "|internal sampled voltage-reference voltage|<first threshold" from the other battery clusters in the power-on group except the first battery cluster, and the second battery cluster also meets the power-on condition.

[0136] In other examples, the specific implementation process of S131 may also be the following steps.

[0137] 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.

[0138] S1312: Based on the status information reported by the main control unit of the battery cluster, determine whether the battery cluster in the middle position meets the power-on permission condition.

[0139] S1313: In response to the battery cluster in the middle position meeting the power-on permission condition, determine the battery cluster as the first battery cluster.

[0140] S1314 , in response to the battery cluster ranked in the middle not satisfying the power-on permission condition, determine the battery cluster ranked in the middle from the remaining battery clusters, and return to S1312 .

[0141] In this example, S1333 can be specifically implemented by 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 "|internal sampling voltage-reference voltage|<first threshold" meets the power-on permission condition; when the power-on permission condition is met, confirm the battery cluster as the second battery cluster.

[0142] The above-mentioned sorting method can be in the order of small to large or in the order of large to small. Here, taking the example of sorting first and then judging whether the power-on condition is met, the internal sampling voltages of Q battery clusters on the branch are sorted in S1311. If Q is an odd number, the (Q+1) / 2th internal sampling voltage is sorted in the middle position; if Q is an even number, the Q / 2th internal sampling voltage is sorted in the middle position or the (Q / 2)+1th internal sampling voltage is sorted in the middle position.

[0143] There are various ways to confirm whether the battery cluster meets the power-on permission condition based on the status information.

[0144] Optionally, the status information reported by the battery management unit to the main control unit includes fault information. 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 status information of the battery cluster received by the control unit includes fault information. The control unit can confirm the fault level of the battery cluster based on the fault information. In response to the fault level of the battery cluster being lower than the first set level, it confirms that the battery cluster meets the allowable power-on condition. Here, it should be noted that the fault level of the battery cluster is from level 1 to level 7, and the higher the fault level, the more serious the fault. The first setting level is a fault level threshold that characterizes the failure of the battery cluster failure and cannot be powered on. It can be selected based on experience and actual working conditions, for example, it can be level 4.

[0145] In other alternative methods, the status information reported by the battery management unit to the main control unit includes fault information. The main control unit can confirm the fault level of the battery cluster based on the status information of the battery pack, and switch the power-on flag from a low level to a high level in response to the fault level of the battery cluster being lower than the first set level (for example, level 4), and report the status information including the power-on signal to the control unit. The control unit receives the status information including the power-on signal and confirms that the battery cluster meets the power-on condition based on the power-on signal.

[0146] In this embodiment, the main control unit does not need to analyze the fault information of the battery cluster to confirm the fault level of the battery cluster. When confirming that the power-on permission signal is received, it can determine that the battery cluster meets the power-on trigger condition. It can be seen that the method of confirming whether the battery cluster meets the power-on trigger condition is fast and simple, which is conducive to improving the operating efficiency of the energy storage system.

[0147] In some embodiments of the present application, in S130, while sending a power-on instruction 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 time, it is confirmed that the battery cluster is powered on successfully; in response to the power-on operation not being completed within the first preset time, it is confirmed that the battery cluster has failed to power on.

[0148] In combination with the foregoing content, it can be seen that in an embodiment where S130 includes S131 to S136, S132 may be to send a power-on instruction 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 the first preset duration, confirming that the first battery cluster is powered on successfully.

[0149] The power-on time refers to the time required for the battery cluster to be connected to the bus so that the battery cluster can operate normally. For a battery cluster that functions normally, its power-on time is generally short. When the power-on time of a battery cluster is too long, it indicates that the battery cluster is not in a normal working state. If it continues to be powered on, it may cause further failures of the battery cluster or even accidents. The first preset time is a pre-set threshold for the power-on time.

[0150] In this embodiment, a first preset time is set as a threshold to confirm 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 time, and the battery cluster that is successfully powered on functions normally. This can reduce the possibility of malfunctions or even accidents caused by powering on a battery cluster that is not functioning normally.

[0151] In some embodiments of the present application, the state information may include not only the internal sampling voltage but also the external sampling voltage. The power-on instruction may be configured to instruct the corresponding battery cluster to power on the pre-charging circuit, obtain the pre-charging time, internal sampling voltage and external sampling voltage of the battery cluster; to instruct the corresponding battery cluster to 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 a second threshold value based on the pre-charging time, the internal sampling voltage and the external sampling voltage; and to instruct the corresponding battery cluster to power on the main circuit of the battery cluster and disconnect the pre-charging circuit in response to 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 being less than the second threshold value.

[0152] Optionally, the power-on instruction may be configured to indicate that the corresponding battery cluster fails to power on in response to the absolute value of the potential difference between the internal sampling voltage and the external sampling voltage of the battery cluster being greater than or equal to a second threshold within a second preset pre-charge time period.

[0153] In other words, combined Figure 6 As shown, the control method after the main control unit of the battery cluster receives the power-on instruction sent by the control unit includes the following S410 to S460.

[0154] S410, the pre-charging circuit of the battery cluster is powered on.

[0155] S420, obtaining the pre-charge duration, internal sampling voltage and external sampling voltage of the battery cluster.

[0156] 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 a second threshold; if so, S440; if not, S460.

[0157] S440, the main circuit of the battery cluster is powered on and the pre-charging circuit is disconnected.

[0158] S450, confirming that the battery cluster is powered on successfully.

[0159] S460, confirming that the battery cluster fails to power on.

[0160] As can be seen from the foregoing, the control unit sends a power-on instruction to the main control unit of the battery cluster, and the main control unit of the battery cluster responds to the power-on instruction. Specifically, the main control unit responds to the power-on instruction to power on the pre-charging circuit of the corresponding battery cluster, which can first control the main negative relay to close, and then control the pre-charging relay to close, so that the pre-charging circuit is turned on.

[0161] The pre-charge duration refers to the time it takes to power on the pre-charge circuit. For a battery cluster that functions normally, the condition “|internal sampling voltage of the battery cluster - external sampling voltage of the battery cluster| < second threshold value” can be met within a shorter pre-charge duration. The condition “|internal sampling voltage of the battery cluster - external sampling voltage of the battery cluster| < second threshold value” is met only when the pre-charge duration is too long, indicating that the battery cluster is not in a normal working state. If it continues to be powered on, it may cause further failures of the battery cluster or even accidents. The second preset duration is a threshold value preset for the pre-charge duration.

[0162] This embodiment is designed such that when the battery cluster is powered on, before the main circuit is powered on, the pre-charging circuit is powered on for pre-charging, which helps to reduce the risk of high voltage shock to the energy storage inverter due to excessive voltage difference between the battery cluster and the energy storage inverter.

[0163] In addition, this embodiment also confirms whether the pre-charging time of the battery cluster is too long by setting a second preset time as a threshold, so that the battery cluster whose pre-charging time is within the second preset time continues to be powered on, which can reduce the possibility of powering on a battery cluster that is not in normal function and causing a malfunction or even an accident. The second preset time can be reasonably designed based on experience and actual working conditions, for example, it can be 100ms or 200ms.

[0164] In some embodiments, the main control unit powers on the main circuit of the battery cluster and disconnects the pre-charging circuit in response to the power-on instruction, which may specifically refer to first controlling the main positive relay to close so that the main circuit is powered on, and then controlling the pre-charging relay to disconnect after a third preset time length to disconnect the pre-charging circuit. The third preset time length may be designed according to experience and requirements, for example, may be 1000ms.

[0165] By designing a delay of a third preset time after the main circuit is powered on and then cutting off the pre-charging circuit, the pre-charging circuit remains in a closed-circuit state during the process of connecting the main circuit to the bus to connect to the high-voltage circuit. This is beneficial to further reduce the possibility of a high-voltage shock to the energy storage inverter caused by an excessively large voltage difference between the internal sampling voltage of the battery cluster and the energy storage inverter.

[0166] In some embodiments, the energy storage system can be confirmed to be powered on successfully in response to at least one battery cluster being powered on successfully in any of the N branches. This is beneficial for all branches of the powered-on energy storage system to be powered on successfully when it is running, thereby improving the external discharge capacity and operating stability of the energy storage system.

[0167] In some embodiments of the present application, after S130, the control method of the energy storage system may further include the following steps.

[0168] S140, confirming whether the total number of battery clusters that have been powered on successfully exceeds the minimum number of operating battery clusters.

[0169] The minimum number of operating battery clusters is pre-set, and the minimum number of operating battery clusters is ≤Q, and may be 1, 2, 3, 4 or 5, for example.

[0170] S150 , in response to the total number of successfully powered-on battery clusters exceeding the minimum number of operating battery clusters, confirming that power-on of the energy storage system is completed.

[0171] In this embodiment, the energy storage system is confirmed to be powered on when the total number of successfully powered-on battery clusters exceeds the minimum number of operating battery clusters. This is beneficial for the energy storage system that has been powered on to have the total number of successfully powered-on battery clusters greater than or equal to the minimum number of operating battery clusters when it is running, so as to meet design requirements and usage requirements.

[0172] In some embodiments of the present application, the control method of the energy storage system may further include:

[0173] Before S110, status information of all battery clusters on N branches is obtained, and the status information may also include fault information; based on the fault information of all battery clusters, the fault level of each battery cluster is determined; it is confirmed 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, S110 is executed.

[0174] As can be seen from the foregoing, the fault level of the battery cluster is from level 1 to level 7. The higher the fault level, the more serious the fault. Among them, the second setting level is used to characterize whether there is a fault level threshold that affects the normal power-on of the battery cluster. For example, the second setting level can be a level 6 fault or a level 7 fault. The second setting level is greater than the first setting level.

[0175] By using this design, by determining the fault level of the battery cluster, the prerequisite for the energy storage system to respond to the power-up 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, that is, the number of battery clusters that can be powered up normally is not less than the minimum number of operating battery clusters, so as to reduce the possibility of powering on the battery clusters in a serious fault state and reduce the adverse effects of the fault on the energy storage system, which is conducive to improving the safety of the energy storage system.

[0176] like Figure 1 and Figure 2 As shown in the embodiment of the present application, an energy storage system also proposes an energy storage system, which includes: N branches, at least one energy storage converter and a control unit; each branch is equipped with a plurality of battery clusters connected in parallel and independent of each other, the battery clusters include at least one battery pack, 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 a corresponding energy storage converter, 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 realize the control method of the energy storage system that performs any of the above embodiments.

[0177] An embodiment of the present 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.

[0178] Various embodiments of the systems and techniques 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 chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include: being implemented in one or more computer programs, which can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a dedicated or general programmable processor, which can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0179] The embodiment of the present application further proposes a computer-readable storage medium, on which instructions are stored. When the instructions are executed individually or collectively by one or more processors of a computer device, the control method of the energy storage system of any of the above embodiments is implemented.

[0180] A computer readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or apparatus. A machine readable medium may be a machine readable signal medium or a machine readable storage medium. A machine readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or device, or any suitable combination of the foregoing. More specific examples of machine readable storage media may include electrical connections based on one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0181] The embodiments of the present application further provide a computer program product, including instructions, which, when executed individually or collectively by one or more processors of a computer device, implement a control method for an energy storage system according to any of the above embodiments.

[0182] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below.

[0183] In the implementation mode of the present application, Figure 1 and Figure 2 As shown, 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 is provided with Q battery clusters connected in parallel and independent of each other, where Q is a positive integer greater than or equal to 3. The battery cluster includes at least one battery group and a main control unit for controlling the operating status of at least one battery group in the battery cluster. Each battery group includes multiple battery cells and a battery management unit for controlling the operating status of multiple battery cells in the battery group. The energy storage converter is electrically connected to the power-consuming equipment and the power generation equipment.

[0184] The control unit is also connected to the main control unit and the energy storage converter via the CAN bus. The main control unit is connected to the battery management unit via the 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 items: internal sampling voltage, external sampling voltage, fault information, power-on permission signal, temperature, health status, etc. The main control unit then reports the status information of the battery pack reported by the battery management unit to the control unit after comprehensive arrangement.

[0185] like Figure 7 As shown, the control method of the energy storage system includes the following steps. The execution subject of the control method of the energy storage system is a control unit.

[0186] S210, obtaining status information of all battery clusters on N branches.

[0187] S220 , based on the fault information of all the battery clusters, determining the fault level of each battery cluster.

[0188] S230 , confirming whether the total number of battery clusters with a fault level lower than level 6 is greater than or equal to the minimum number of operating battery clusters.

[0189] S240 , in response to the total number of battery clusters with fault levels lower than level 6 being greater than or equal to the minimum number of operating battery clusters, obtaining a power-on request.

[0190] S250 , in response to the power-on request, obtaining status information of all battery clusters on each branch.

[0191] S260, for any one of the N branches, based on the status information of all battery clusters on the branch, a power-on instruction is sent to one of the battery clusters on the branch or to M battery clusters on the branch that meet voltage balance, where M is a positive integer greater than or equal to 2, and voltage balance means that the voltage value related to a battery cluster among the M is used as a reference voltage, and the difference between the internal sampled voltages of the remaining battery clusters among the M and the reference voltage is less than a first threshold value, and the power-on instruction is used to instruct the corresponding battery cluster to perform a power-on operation.

[0192] S270 , confirm whether the total number of battery clusters that have been powered on successfully is greater than or equal to the minimum number of operating battery clusters.

[0193] S280 , in response to the total number of successfully powered-on battery clusters being greater than or equal to the minimum number of operating battery clusters, confirming that the energy storage system is powered-on successfully, and issuing a power request instruction.

[0194] S290 , in response to the total number of successfully powered-on battery clusters being less than the minimum number of operating battery clusters, issuing a power-on failure instruction.

[0195] In step S260 , the power-on process for any one of the N branches includes the following steps S31 to S44 .

[0196] S31, based on the status information of all battery clusters on the branch, select battery clusters that meet the power-on condition (fault level of the battery cluster is lower than level 4) from all battery clusters as the power-on group.

[0197] S32, sorting the internal sampled voltages of the battery clusters in the power-on group from small to large, and determining the battery cluster with the internal sampled voltage in the middle position in the power-on group as the first battery cluster. In this step, when the power-on group has an odd number of battery clusters, the battery cluster with the internal sampled voltage ranked (the number of battery clusters / 2)th is determined as the first battery cluster. When the power-on group has an even number of battery clusters, the battery cluster with the internal sampled voltage ranked (the number of battery clusters / 2)+1th is determined as the first battery cluster.

[0198] S33, sending a power-on instruction to the first battery cluster, and at the same time, timing the power-on time of the first battery cluster.

[0199] S34, confirm whether the first battery cluster completes the power-on operation within the first preset time period; if so, go to S35; if not, go to S43.

[0200] S35 , in response to the first battery cluster completing the power-on operation within the first preset time period, confirming that the first battery cluster is powered on successfully.

[0201] S36, obtaining an external sampled voltage of the first battery cluster and setting it as a reference voltage.

[0202] S37, confirm whether there is a battery cluster satisfying "|internal sample voltage-reference voltage|<first threshold" among other battery clusters in the group that can be powered on.

[0203] S38, if the result of the judgment is yes, the battery cluster in the power-on group that satisfies “|internal sample voltage-reference voltage|<first threshold” is determined as the second battery cluster.

[0204] S39, sending a power-on instruction to the second battery cluster, and at the same time, timing the power-on time of the second battery cluster.

[0205] S40, confirming whether the second battery cluster completes the power-on operation within a first preset time period.

[0206] S41, in response to the second battery cluster completing the power-on operation within the first preset time period, confirming that the second battery cluster is powered on successfully.

[0207] S42: In response to the second battery cluster not completing the power-on operation within the first preset time period, confirming that the second battery cluster fails to power on.

[0208] S43 , in response to the first battery cluster not completing the power-on operation within the first preset time period, confirming that the first battery cluster has failed to power on, and then proceeding to S44 .

[0209] S44, re-arrange the internal sampled voltages of the remaining battery clusters in the power-on group, and determine the battery cluster in the middle position in the arrangement as a new first battery cluster, and return to S33.

[0210] In this article, sending a power-on instruction may specifically refer to the control unit sending a power-on instruction to the main control unit of the battery cluster, and the main control unit responds to the power-on instruction according to Figure 6 The control process shown controls the corresponding battery cluster to power on.

[0211] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A control method for an energy storage system, characterized in that: The energy storage system includes N branches and at least one energy storage converter, each branch is provided with a plurality of independent battery clusters, the 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 comprises: Get power-on request; In response to the power-on request, acquiring status information of all the battery clusters on each of the branches, the status information including internal sampled voltage, external sampled voltage and fault information; and For any of the N branches, based on the status information of all the battery clusters on the branch, a power-on instruction is sent to one of the battery clusters on the branch that meets the power-on permission condition, so that the one of the battery clusters is powered on successfully, or a power-on instruction is sent to all M battery clusters on the branch that meet the power-on permission condition and meet voltage balancing, so that the M battery clusters are all powered on successfully, M is a positive integer greater than or equal to 2, the voltage balancing means that the voltage value related to a battery cluster among the M battery clusters is used as a reference voltage, and the difference between the internal sampling voltage of the remaining battery clusters among the M battery clusters and the reference voltage is less than a first threshold value; wherein the power-on permission condition includes a fault level lower than a first set level, and the power-on instruction is used to instruct the corresponding battery cluster to perform a power-on operation, and is used to instruct the corresponding battery cluster to respond to the absolute value of the potential difference between the internal sampling voltage and the external sampling voltage of the battery cluster within a second preset time length, so that the main circuit of the battery cluster is powered on and the pre-charging circuit is disconnected.

2. The control method of the energy storage system according to claim 1, characterized in that: The sending of a power-on instruction to one of the battery clusters on the branch or to all the M battery clusters on the branch that meet voltage balance for any one of the N branches based on the status information of all the battery clusters on the branch includes: For any branch among the N branches, determining a first battery cluster among all the battery clusters based on the status information of all the battery clusters on the branch; sending the power-on instruction to the first battery cluster; When the first battery cluster is powered on successfully, confirm whether there is a second battery cluster on the branch, the voltage of the second battery cluster is balanced with that of the first battery cluster, and the reference voltage is related to the first battery cluster; In response to the second battery cluster being present on the branch line, the power-on instruction is sent to the second battery cluster.

3. The control method of the energy storage system according to claim 2, characterized in that: The step of confirming whether there is a second battery cluster on the branch circuit when the first battery cluster is powered on successfully, the voltage of the second battery cluster is balanced with that of the first battery cluster, and the reference voltage is related to the first battery cluster specifically includes: When the first battery cluster is powered on successfully, obtaining the reference voltage, where the reference voltage is an external sampling voltage of the first battery cluster; Determine whether, among the remaining battery clusters on the branch, there is a battery cluster whose absolute value of the difference between the internal sampling voltage and the reference voltage is smaller than the first threshold; Based on the determination result, it is confirmed whether the second battery cluster exists.

4. The control method of the energy storage system according to claim 2, characterized in that: Each of the branches is provided with at least three battery clusters; The determining of the first battery cluster among all the battery clusters specifically includes: A battery cluster whose internal sampled voltage is ranked in the middle among all the battery clusters is determined as the first battery cluster.

5. The control method of the energy storage system according to claim 1, characterized in that: While sending the power-on instruction to any one of the battery clusters, timing the power-on time of the battery cluster; In response to the battery cluster completing the power-on operation within the first preset time period, it is confirmed that the battery cluster is powered on successfully.

6. The control method of the energy storage system according to claim 1, characterized in that: The power-on instruction is configured to instruct the corresponding pre-charging circuit of the battery cluster to power on, and obtain the pre-charging time, 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 within the second preset time period is less than a second threshold; It is also used to indicate that within the 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 value, so that the main circuit of the battery cluster is powered on and the pre-charging circuit is disconnected.

7. The control method of the energy storage system according to any one of claims 1 to 6, characterized in that: After sending a power-on instruction to one of the battery clusters on the branch or to all the M battery clusters on the branch that meet voltage balance for any one of the N branches based on the status information of all the battery clusters on the branch, the method further includes: Confirm whether the total number of the battery clusters that are successfully powered on is greater than or equal to the minimum number of operating battery clusters; In response to the total number of the battery clusters that are successfully powered on being greater than or equal to the minimum number of operating battery clusters, it is confirmed that the power-on of the energy storage system is completed.

8. The control method of the energy storage system according to any one of claims 1 to 6, characterized in that: Before obtaining the power-on request, obtaining status information of all the battery clusters on the N branches, wherein the status information also includes fault information; Based on the fault information of all the battery clusters, determining the fault level of each of the battery clusters; confirming 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; In response to the total number of battery clusters having a fault level lower than the second set level being greater than or equal to the minimum number of operating battery clusters, the power-on request is acquired.

9. An energy storage system, characterized in that: include: N branches, each of which is provided with a plurality of battery clusters, each of which includes at least one battery pack, and N is a positive integer greater than or equal to 2; At least one energy storage converter, each of which is electrically connected to one branch or K branches connected in parallel, and the battery cluster of each branch can be charged or discharged through the corresponding energy storage converter, K is a positive integer greater than or equal to 2 and less than or equal to N; as well as A control unit is electrically connected to the at least one energy storage converter, and the control unit is configured to implement the control method of the energy storage system according to any one of claims 1 to 8.

10. A computer device, characterized in that: include: at least one memory storing instructions; as well as At least one processor is communicatively connected to the at least one memory, and the at least one processor executes the instruction individually or collectively to implement the control method of the energy storage system according to any one of claims 1 to 8.

11. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions, and when the instructions are executed individually or collectively by one or more processors of a computer device, the control method of the energy storage system according to any one of claims 1 to 8 is implemented.

12. A computer program product, characterized in that The method comprises instructions which, when executed individually or collectively by one or more processors of a computer device, implement the control method of the energy storage system according to any one of claims 1 to 8.

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