Energy storage system and energy management method thereof, electronic equipment and storage medium

Abstract

The invention relates to the technical field of battery energy management, particularly provides an energy storage system and an energy management method thereof, electronic equipment and a storage medium, and aims to solve the problems of improving the storage efficiency of the energy storage system and balancing the energy of a battery cluster. The method provided by the invention comprises the steps of performing power distribution on an operating battery cluster according to first charging / discharging power of a battery stack and SOC of the operating battery cluster, and determining second charging / discharging power of the operating battery cluster; controlling the DC / DC corresponding to the running battery cluster according to the second charging / discharging power, and charging / discharging the running battery cluster; determining a first battery cluster needing to be charged and a second battery cluster not needing to be charged according to the SOC of each battery cluster in the battery stack; and controlling the first battery cluster and the second battery cluster to charge and discharge mutually through the DC / DC corresponding to the first battery cluster and the second battery cluster until the SOC is the same. Based on the method, the storage efficiency of the energy storage system can be improved, and the energy of the battery clusters is balanced.

Description

Technical Field

[0001] The present application relates to the technical field of battery energy management, and in particular to an energy storage system and an energy management method thereof, an electronic device, and a storage medium. Background Art

[0002] Energy storage systems are usually managed by an energy management system (EMS) to manage one or more energy storage subsystems, which may include a battery management system (BMS) and a power conversion system (PCS). The management architecture of the battery management system BMS is a three-level management architecture consisting of a master battery management unit (BAU), multiple slave battery management units (BCU) and multiple battery management units (BMU). The master battery management unit BAU is used to manage the battery stack, which includes multiple battery clusters, and the battery cluster includes multiple battery modules; multiple slave battery management units BCU are used to manage a battery cluster respectively; multiple battery management units BMU are used to manage battery packs respectively.

[0003] The energy storage subsystem also includes a high-voltage control box, which can perform energy conversion and storage on the battery cluster. For example, when charging, the AC power input from the external system is converted into DC power, so that the DC power is input into the battery cluster for storage; when discharging, the DC power output from the battery cluster is converted into AC power, so that the AC power is output to the external system. However, the high-voltage control box is highly dependent on the battery management system BMS to monitor the battery status when working. If there is an error or delay in the monitoring result, it may affect the working safety and efficiency of the high-voltage control box. In addition, the high-voltage control box performs energy conversion and storage on the battery cluster according to the stack-level allowable charge and discharge power obtained by the battery management system BMS. The stack-level allowable charge and discharge power is the product of the allowable charge and discharge power of the target battery cluster in the battery stack and the number of running battery clusters, where the running battery cluster is the battery cluster in the running state, and the target battery cluster is the running battery cluster with the smallest allowable charge and discharge power. Since the stack-level allowable charge and discharge power is not the cumulative sum of the allowable charge and discharge powers of all running battery clusters, when charging and discharging according to the stack-level allowable charge and discharge power, it may cause insufficient charge and discharge of individual battery clusters, thereby reducing the storage efficiency of the entire energy storage subsystem. In addition, when the energy difference between battery clusters increases due to self-consumption, capacity attenuation and other reasons, the battery clusters can only be replenished manually to balance the energy between the battery clusters, which is a cumbersome operation.

[0004] Accordingly, the art needs a new technical solution to solve the above problems. Summary of the invention

[0005] In order to overcome the above-mentioned defects, the present application is proposed to solve or at least partially solve the technical problems of improving the storage efficiency of the energy storage system and ensuring the energy balance of the battery cluster in the energy storage system.

[0006] In a first aspect, an energy management method for an energy storage system is provided, wherein the energy storage system comprises an energy management system EMS and an energy storage subsystem, wherein the energy storage subsystem comprises a battery management system BMS and a battery stack, wherein the battery stack comprises a plurality of battery clusters, wherein the battery management system BMS comprises a plurality of battery management units BCU, wherein the plurality of battery management units BCU correspond one-to-one to the plurality of battery clusters, wherein the energy storage subsystem further comprises a plurality of DC / DCs, wherein the plurality of DC / DCs correspond one-to-one to the plurality of battery clusters, wherein the method is applied to the energy management system EMS, and wherein the method comprises:

[0007] When the energy storage subsystem is running, power is allocated to the running battery cluster according to the first charging / discharging power of the battery stack and the state of charge SOC of the running battery cluster in the battery stack to determine the second charging / discharging power of the running battery cluster; and the DC / DC corresponding to the running battery cluster is controlled according to the second charging / discharging power to charge / discharge the running battery cluster;

[0008] When the energy storage subsystem is not in operation, a first battery cluster that needs to be recharged and a second battery cluster that does not need to be recharged are determined according to the state of charge (SOC) of each battery cluster in the battery stack; and mutual charging and discharging between the first battery cluster and the second battery cluster are controlled through the DC / DC corresponding to the first battery cluster and the second battery cluster until the state of charge (SOC) of the first battery cluster and the second battery cluster are the same.

[0009] In a technical solution of the above energy management method, determining a first battery cluster that needs to be recharged and a second battery cluster that does not need to be recharged according to the state of charge SOC of each battery cluster in the battery stack includes:

[0010] Obtaining a balancing target value according to an average value of the state of charge (SOC) of all battery clusters in the battery stack;

[0011] If the state of charge (SOC) of the battery cluster is less than the balancing target value, the battery cluster is a first battery cluster that needs to be recharged; if the state of charge (SOC) of the battery cluster is greater than or equal to the balancing target value, the battery cluster is a second battery cluster that does not need to be recharged.

[0012] In a technical solution of the above energy management method, the energy storage subsystem includes a power conversion system PCS, a first DC side of the DC / DC is connected to a DC bus of the power conversion system PCS, a second DC side of the DC / DC is connected to the battery cluster, and the mutual charging and discharging between the first battery cluster and the second battery cluster is controlled by the DC / DC corresponding to the first battery cluster and the second battery cluster, including:

[0013] Controlling the DC / DC corresponding to the second battery cluster to operate in a discharge mode, so as to control the second battery cluster to discharge through the DC bus of the power conversion system PCS;

[0014] The DC / DC corresponding to the first battery cluster is controlled to operate in a charging mode, so as to control the first battery cluster to be charged via the DC bus of the power conversion system PCS.

[0015] In a technical solution of the above energy management method, the method further includes:

[0016] Controlling the DC / DC corresponding to the first battery cluster to operate in a constant voltage charging mode, and controlling the DC / DC corresponding to the second battery cluster to operate in a constant current discharging mode;

[0017] or,

[0018] The DC / DC corresponding to the first battery cluster is controlled to operate in a constant current charging mode, and the DC / DC corresponding to the second battery cluster is controlled to operate in a constant voltage discharging mode.

[0019] In a technical solution of the above energy management method, the power allocation to the operating battery cluster according to the first charging / discharging power of the battery stack and the state of charge SOC of the operating battery cluster in the battery stack includes:

[0020] Obtaining a battery stack SOC of the battery stack, where the battery stack SOC is the sum of the states of charge SOCs of all operating battery clusters in the battery stack;

[0021] Respectively obtaining a SOC ratio between the state of charge SOC of each of the operating battery clusters and the SOC of the battery stack, and obtaining a power allocation ratio of the operating battery cluster according to the SOC ratio of the operating battery cluster;

[0022] Power is distributed to the operating battery cluster according to the first charge / discharge power of the battery stack and the power distribution ratio of the operating battery cluster.

[0023] In a technical solution of the above energy management method, the step of obtaining the power allocation ratio of the operating battery cluster according to the SOC ratio of the operating battery cluster includes:

[0024] When the first charging / discharging power and the second charging / discharging power are both discharging powers, the SOC ratio of the operating battery cluster is used as the power allocation ratio of the operating battery cluster;

[0025] When the first charging / discharging power and the second charging / discharging power are both charging powers, the operating battery clusters are sorted in descending order of the state of charge SOC to form a battery cluster sequence, the SOC ratios of the operating battery clusters are sorted in descending order to form an SOC ratio sequence, and the i-th SOC ratio in the SOC ratio sequence is used as the power allocation ratio of the j-th operating battery cluster in the battery cluster sequence, i=j.

[0026] In a technical solution of the above energy management method, the power allocation to the operating battery cluster according to the first charge / discharge power of the battery stack and the power allocation ratio of the operating battery cluster includes:

[0027] acquiring an ideal power value of the operating battery cluster according to a product of the first charging / discharging power and the power allocation ratio of the operating battery cluster;

[0028] If the ideal power value is greater than or equal to the preset power extreme value, the operating battery cluster is an excess battery cluster, and a second charging / discharging power of the excess battery cluster is obtained according to the preset power extreme value;

[0029] If the ideal power value is less than the preset power extreme value, the operating battery cluster is a non-excess battery cluster, and a second charging / discharging power of the non-excess battery cluster is obtained according to the ideal power value;

[0030] in,

[0031] The preset power limit is a charging / discharging power limit of the operating battery cluster or the preset power limit is a power limit of a DC / DC corresponding to the operating battery cluster.

[0032] In a technical solution of the above energy management method, the method further includes:

[0033] Obtaining a power difference between an ideal power value of the excess battery cluster and the preset power extreme value;

[0034] Obtaining the remaining charging / discharging power according to the power difference of all excess battery clusters;

[0035] Power is again allocated to the non-excess battery cluster according to the remaining charge / discharge power and the power allocation ratio of the non-excess battery cluster.

[0036] In a technical solution of the above energy management method, the energy storage subsystem includes a power conversion system PCS, the first DC side of the DC / DC is connected to the DC bus of the power conversion system PCS, the second DC side of the DC / DC is connected to the battery cluster, and the DC / DC corresponding to the operating battery cluster is controlled according to the second charging / discharging power to charge / discharge the operating battery cluster, including:

[0037] Determining a target charging / discharging current of a DC / DC corresponding to the operating battery cluster according to a second charging / discharging power of the operating battery cluster and a voltage of the DC bus;

[0038] Adopting a droop control method, determining a droop control parameter of the DC / DC according to a target charge / discharge current of the DC / DC, wherein the droop control parameter includes a virtual resistance of the DC / DC; and,

[0039] An actual charge / discharge current of the DC / DC is adjusted according to the virtual resistance so that the actual charge / discharge current is the same as the target charge / discharge current.

[0040] In a technical solution of the above energy management method, the method further includes:

[0041] If the target charge / discharge current exceeds the charge / discharge current limit of the DC / DC, the actual charge / discharge current of the DC / DC is adjusted to the charge / discharge current limit.

[0042] In a second aspect, an energy storage system is provided, the energy storage system includes an energy management system EMS and an energy storage subsystem, the energy storage subsystem includes a battery management system BMS and a battery stack, the battery stack includes a plurality of battery clusters, the battery management system BMS includes a plurality of battery management units BCU, the plurality of battery management units BCU correspond one-to-one to the plurality of battery clusters, the energy storage subsystem also includes a plurality of DC / DCs, the plurality of DC / DCs correspond one-to-one to the plurality of battery clusters; wherein the energy management system EMS is used to execute the energy management method of the energy storage system provided in the first aspect.

[0043] In a third aspect, an electronic device is provided, comprising at least one processor; and a memory communicatively connected to the at least one processor; wherein a computer program is stored in the memory, and when the computer program is executed by the at least one processor, the method described in any one of the technical solutions of the energy management method of the above-mentioned energy storage system is implemented.

[0044] In a fourth aspect, a computer-readable storage medium is provided, wherein a plurality of program codes are stored therein, wherein the program codes are suitable for being loaded and run by a processor to execute the method described in any one of the technical solutions of the energy management method of the above-mentioned energy storage system.

[0045] The above one or more technical solutions of the present application have at least one or more of the following beneficial effects:

[0046] In a technical solution for implementing the energy management method of the energy storage system provided in the present application, the energy storage system includes an energy management system EMS and an energy storage subsystem, the energy storage subsystem includes a battery management system BMS and a battery stack, the battery stack includes multiple battery clusters, the battery management system BMS includes multiple battery management units BCU, the multiple battery management units BCU correspond one-to-one to the multiple battery clusters, and the energy storage subsystem also includes multiple DC / DCs, the multiple DC / DCs correspond one-to-one to the multiple battery clusters. In the above technical solution, the above method is applied to the energy management system EMS, and the above method includes the following steps: when the energy storage subsystem is running, according to the first charge / discharge power of the battery stack and the state of charge SOC of the running battery cluster in the battery stack, power is allocated to the running battery cluster to determine the second charge / discharge power of the running battery cluster; and according to the second charge / discharge power, the DC / DC corresponding to the running battery cluster is controlled to charge / discharge the running battery cluster. When the energy storage subsystem is not in operation, a first battery cluster that needs to be recharged and a second battery cluster that does not need to be recharged are determined according to the state of charge SOC of each battery cluster in the battery stack; and the first battery cluster and the second battery cluster are controlled to be charged and discharged with each other through the DC / DC corresponding to the first battery cluster and the second battery cluster until the state of charge SOC of the first battery cluster and the second battery cluster are the same.

[0047] Based on the above implementation scheme, when the energy storage subsystem is running, the DC / DC can be used to control the charge and discharge of the running battery cluster. Since the DC / DC has an independent central controller, it does not rely on the battery management system BMS when working, and has protection functions such as overcurrent, overvoltage, and undervoltage. Therefore, compared with the high-voltage control box, it can ensure the safety and efficiency of the charge and discharge control. In addition, when the energy storage subsystem is running, the first charge / discharge power of the battery stack and the state of charge SOC of the running battery cluster in the battery stack are used to distribute power to the running battery cluster, which can avoid the problem that the individual battery clusters are not fully charged and discharged, resulting in a reduction in the storage efficiency of the entire energy storage subsystem. In addition, when the energy storage subsystem is not running, the DC / DC can be used to control the mutual charge and discharge between the first battery cluster that needs to be supplemented and the second battery cluster that does not need to be supplemented, to ensure the energy balance of the battery cluster, and realize the automatic balance control of the battery cluster. Compared with the manual supplement method, the convenience of energy balance control is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The disclosure of the present application will become easier to understand with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present application. Among them:

[0049] Figure 1 is a schematic diagram of the main structure of an energy storage system according to an embodiment of the present application;

[0050] Figure 2 is a flowchart of the main steps of an energy management method according to an embodiment of the present application;

[0051] Figure 3 is a schematic flow chart of the main steps of power distribution for a running battery cluster according to an embodiment of the present application;

[0052] Figure 4 This is a schematic flow chart of the main steps of controlling the DC / DC corresponding to the operating battery cluster to charge / discharge the operating battery cluster according to an embodiment of the present application;

[0053] Figure 5 This is a schematic diagram of the main steps of determining a first battery cluster that needs to be recharged and a second battery cluster that does not need to be recharged according to an embodiment of the present application;

[0054] Figure 6 is a schematic flow chart of main steps of controlling mutual charging and discharging between a first battery cluster and a second battery cluster according to an embodiment of the present application;

[0055] Figure 7 is a schematic diagram of the main structure of an electronic device according to an embodiment of the present application;

[0056] Figure 8 It is a schematic diagram of the main structure of the energy storage system in the prior art;

[0057] Fig. 9 It is a main structural diagram of an energy storage subsystem according to an embodiment of the present application.

[0058] Reference numerals:

[0059] 11: memory; 12: processor. DETAILED DESCRIPTION

[0060] Some embodiments of the present application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application and are not intended to limit the protection scope of the present application.

[0061] In the description of this application, "processor" may include hardware, software or a combination of the two. The processor may be a central processing unit, a microprocessor, an image processor, a digital signal processor or any other suitable processor. The processor has data and / or signal processing functions. The processor may be implemented in software, hardware or a combination of the two. Computer-readable storage media include any suitable medium that can store program code, such as a disk, a hard disk, an optical disk, a flash memory, a read-only memory, a random access memory, etc.

[0062] Here we first explain some terms involved in this application.

[0063] DC / DC is a Direct Current to Direct Current Converter, which can realize bidirectional conversion of DC power. For example, DC / DC includes two DC sides (hereinafter described as the first DC side and the second DC side). If the first DC side inputs the first DC power with a voltage of A, the DC / DC can be controlled to convert the first DC power into the second DC power with a voltage of B, and the second DC power is output through the second DC side; if the second DC side inputs the second DC voltage, the DC / DC can also be controlled to convert the second DC power into the first DC power, and the first DC power is output through the first DC side.

[0064] An embodiment of the energy management method for the energy storage system provided in the present application is described below.

[0065] First, the energy storage system in this embodiment is described.

[0066] In this embodiment, the energy storage system includes an energy management system EMS (Energy Management System) and at least one energy storage subsystem. The energy storage subsystem includes a battery management system BMS (Battery Management System), a battery stack, and at least one DC / DC. The battery stack includes multiple battery clusters, and the battery management system BMS includes multiple battery management units BCU (Battery Control Unit), and the multiple battery management units BCU correspond to the multiple battery clusters one by one, and the multiple DC / DCs correspond to the multiple battery clusters one by one.

[0067] See attached Figure 1 , Figure 1 The main structure of the energy storage system is shown as an example. Figure 1 As shown, the energy storage system includes an energy management system EMS and N energy storage subsystems, N ≥ 1.

[0068] Each energy storage subsystem includes a battery management system BMS ( Figure 1(not shown), a battery stack and M DC / DCs, the battery management system BMS includes M battery management units BCU, the battery stack includes M battery clusters, M≥1. The M DC / DCs correspond to the M battery clusters one by one, and each DC / DC is connected to its corresponding battery cluster; the M battery management units BCU correspond to the M battery clusters one by one, and each battery management unit BCU is connected to its corresponding battery cluster.

[0069] The energy management method in this embodiment is described below.

[0070] See attached Figure 2 , Figure 2 FIG. 1 is a flow chart of the main steps of an energy management method according to an embodiment of the present application. Figure 2 As shown, the energy management method in the embodiment of the present application mainly includes performing energy management on the energy storage subsystem through the following steps S101 to S105.

[0071] Step S101: determine the operating status of the energy storage subsystem; if the energy storage subsystem is operating, execute steps S102 and S103; if the energy storage subsystem is not operating, execute steps S104 and S105.

[0072] Step S102: Allocate power to the operating battery cluster according to the first charge / discharge power of the battery stack and the state of charge (SOC) of the operating battery cluster in the battery stack to determine the second charge / discharge power of the operating battery cluster.

[0073] If the operating state of the battery stack is the charging state, the operating battery cluster in the battery stack is the battery cluster being charged. At this time, power is allocated to the operating battery cluster according to the first charging power of the battery stack, and the sum of the second charging powers allocated to all operating battery clusters is equal to the first charging power.

[0074] If the operating state of the battery stack is the discharge state, the operating battery cluster in the battery stack is the battery cluster that is discharging. At this time, power is allocated to the operating battery cluster according to the first discharge power of the battery stack, and the sum of the second discharge powers allocated to all operating battery clusters is equal to the first discharge power.

[0075] During charging, the remaining capacity of the operating battery cluster can be determined based on the state of charge SOC of the operating battery cluster; if the remaining capacity is small, more charging power can be allocated to the operating battery cluster; otherwise, less charging power can be allocated to the operating battery cluster.

[0076] During discharge, if the remaining capacity of the operating battery cluster is large, more discharge power may be allocated to the operating battery cluster; otherwise, less discharge power may be allocated to the operating battery cluster.

[0077] Step S103: controlling the DC / DC corresponding to the operating battery cluster according to the second charging / discharging power, and charging / discharging the operating battery cluster.

[0078] During charging, the current on the DC / DC battery side can be controlled to be negative (i.e., charging current), so that external electric energy can charge the battery cluster through the DC / DC. The battery side is the DC side of the DC / DC connected to the battery cluster, and the magnitude of the charging current can be determined according to the second charging power. During discharging, the current on the DC / DC battery side can be controlled to be positive (i.e., discharging current), so that the battery cluster can discharge outward through the DC / DC, and the magnitude of the discharging current can be determined according to the second discharging power. In this embodiment, a conventional DC / DC control method can be used to charge and discharge the running battery cluster.

[0079] In the method described in the above steps S102 to S103, since the DC / DC has an independent central controller, it does not rely on the battery management system BMS when working, and has protection functions such as overcurrent, overvoltage, and undervoltage. Therefore, compared with the high-voltage control box, the safety and efficiency of charge and discharge control can be guaranteed. In addition, by allocating power to the running battery clusters according to the state of charge SOC of the running battery clusters in the battery stack, it can avoid the problem of insufficient charging and discharging of individual battery clusters, resulting in reduced storage efficiency of the entire energy storage subsystem.

[0080] Step S104: determining a first battery cluster that needs to be recharged and a second battery cluster that does not need to be recharged according to the state of charge SOC of each battery cluster in the battery stack.

[0081] Under normal circumstances, the energy stored in each battery cluster in the battery stack is basically the same, that is, energy balance. However, due to self-consumption, capacity attenuation and other reasons, the energy stored in different battery clusters may be different. For this reason, the electrical energy of the battery cluster energy needs to be adjusted to maintain energy balance.

[0082] According to the state of charge SOC of the battery cluster, the remaining capacity of the battery cluster can be determined. The remaining capacity can also be understood as the energy actually stored in the battery cluster. The larger the state of charge SOC, the more the remaining capacity, and vice versa. Therefore, according to the state of charge SOC, it can be determined which battery clusters need to be supplemented with energy, that is, replenished, and which battery clusters do not need to be supplemented with energy, that is, do not need to be supplemented.

[0083] Step S105: Controlling mutual charging and discharging between the first battery cluster and the second battery cluster through the DC / DC corresponding to the first battery cluster and the second battery cluster until the state of charge SOC of the first battery cluster and the second battery cluster are the same.

[0084] Specifically, the DC / DC corresponding to the second battery cluster controls the discharge of the second battery cluster, and the DC / DC corresponding to the first battery cluster controls the charging of the first battery cluster. The energy released by the second battery cluster can be stored in the first battery cluster by the DC / DC corresponding to the second battery cluster and the DC / DC corresponding to the first battery cluster, thereby realizing automatic charging of the first battery cluster. When the state of charge SOC of the first and second battery clusters is the same, it means that the remaining capacity of the first and second battery clusters is the same, and at this time, the first and second battery clusters have achieved energy balance.

[0085] Based on the method described in steps S104 to S105 above, when there are differences in the energy stored in the battery clusters in the battery stack, the battery clusters can be automatically recharged by DC / DC to ensure energy balance of the battery clusters. Compared with manual recharging, the convenience of energy balance control is greatly improved.

[0086] The above steps S102 to S105 are further explained below.

[0087] 1. Explain step S102.

[0088] In some implementations of the above step S102, Figure 3 The following steps S1021 to S1023 are shown to distribute power to the operating battery clusters.

[0089] Step S1021: Obtain the battery stack SOC of the battery stack, where the battery stack SOC is the sum of the states of charge SOC of all operating battery clusters in the battery stack.

[0090] Step S1022: respectively obtaining the SOC ratio between the state of charge SOC of each operating battery cluster and the SOC of the battery stack, and obtaining the power allocation ratio of the operating battery cluster according to the SOC ratio of the operating battery cluster.

[0091] The SOC ratio of the operating battery cluster ranges from 0 to 1. The higher the SOC ratio, the higher the proportion of the remaining capacity of the operating battery cluster in the remaining capacity of the entire battery stack, that is, the more remaining capacity; otherwise, it indicates less remaining capacity.

[0092] According to the description of step S102 in the above embodiment, when charging, if the remaining capacity is small, more charging power can be allocated to the running battery cluster; if the remaining capacity is large, less charging power can be allocated to the running battery cluster. Based on this, the difference obtained by subtracting the SOC ratio from 1 is obtained, and this difference is used as the power allocation ratio of the running battery cluster. When discharging, if the remaining capacity is large, more discharge power can be allocated to the running battery cluster; otherwise, less discharge power can be allocated to the running battery cluster. Based on this, the SOC ratio can be used as the power allocation ratio of the running battery cluster.

[0093] Step S1023: Allocate power to the operating battery cluster according to the first charge / discharge power of the battery stack and the power allocation ratio of the operating battery cluster.

[0094] In this embodiment, the product of the first charging / discharging power and the power allocation ratio can be obtained, and the second charging / discharging power allocated to the operating battery cluster can be obtained according to the product. Specifically, during charging, the first product of the first charging power and the power allocation ratio is obtained, and the first product is used as the second charging power; the second product of the first discharging power and the power allocation ratio is obtained, and the second product is used as the second discharging power.

[0095] For example, there are four operating battery clusters 1-4 in the battery stack, and the state of charge SOC of the four operating battery clusters 1-4 are SOC1 to SOC4. Therefore, the SOC ratios of the four operating battery clusters 1-4 are:

[0096] k1=SOC1 / (SOC1+SOC2+SOC3+SOC);

[0097] k2=SOC2 / (SOC1+SOC2+SOC3+SOC);

[0098] k3=SOC3 / (SOC1+SOC2+SOC3+SOC);

[0099] k4=SOC4 / (SOC1+SOC2+SOC3+SOC).

[0100] During charging, the first charging power is Pc, and the second charging powers of the four operating battery clusters 1-4 are respectively: (1-k1)×Pc, (1-k2)×Pc, (1-k3)×Pc, and (1-k4)×Pc.

[0101] During discharge, the first discharge power is Pd, and the second discharge powers of the four operating battery clusters 1-4 are respectively: k1×Pc, k2×Pc, k3×Pc, and k4×Pc.

[0102] Based on the method described in steps S1021 to S1023 above, the state of charge SOC of the operating battery cluster can be used to conveniently and accurately complete the power allocation of the operating battery cluster.

[0103] The above steps S1022 and S1023 are further explained below.

[0104] (i) Explain step S1022.

[0105] In some embodiments of the above step S1022, when both the first charge / discharge power and the second charge / discharge power are discharge powers (i.e., during discharging), the SOC ratio of the operating battery cluster is used as the power distribution ratio of the operating battery cluster. When both the first charge / discharge power and the second charge / discharge power are charge powers (i.e., during charging), the power distribution ratio is obtained through the following steps 11 to 13.

[0106] Step 11: Sort the operating battery clusters in descending order of state of charge (SOC) to form a battery cluster sequence. Step 12: Sort the SOC ratios of the operating battery clusters in ascending order to form an SOC ratio sequence. Step 13: Use the i-th SOC ratio in the SOC ratio sequence as the power distribution ratio of the j-th operating battery cluster in the battery cluster sequence, where i = j.

[0107] For example: There are four operating battery clusters 1-4 in the battery stack. The SOC ratios of these four operating battery clusters 1-4 are k1-k4 respectively, and k1 < k2 < k3 < k4. Then the power distribution ratios of these four operating battery clusters 1-4 are k4, k3, k2, k1. If the first charging power is Pc, the second charging powers of these four operating battery clusters 1-4 are: k4×Pc, k3×Pc, k2×Pc, k1×Pc.

[0108] Based on the method described in the above steps 11 to 13, the power distribution ratio of the operating battery cluster during charging can be obtained quickly and accurately by using the magnitude relationship between the SOC ratios.

[0109] (2) Explanation of step S1023.

[0110] In some embodiments of the above step S1023, the power of the operating battery cluster can be distributed through the following steps 21 to 24 and according to the power distribution ratio of the operating battery cluster.

[0111] Step 21: Obtain the ideal power value of the operating battery cluster according to the product of the first charge / discharge power and the power distribution ratio of the operating battery cluster. Specifically, this product can be used as the ideal power value.

[0112] Step 22: Determine whether the ideal power value is greater than or equal to the preset power extreme value. The preset power extreme value is the charge / discharge power extreme value of the operating battery cluster or the power extreme value of the corresponding DC / DC of the operating battery cluster.

[0113] If it is greater than or equal to the preset power extreme value, it indicates that the ideal power value exceeds the rated power value that the operating battery cluster can charge / discharge or the power extreme value of DC / DC. At this time, the ideal power value cannot be used as the second charging / discharging power of the operating battery cluster. Therefore, go to step 23 to obtain the second charging / discharging power according to the preset power extreme value.

[0114] If it is less than the preset power limit, it indicates that the ideal power value does not exceed the rated power value that the operating battery cluster can charge / discharge or the power limit of DC / DC, and the ideal power value can be used as the second charging / discharging power of the operating battery cluster. Therefore, go to step 24 to obtain the second charging / discharging power according to the ideal power value.

[0115] Step 23: operating the battery cluster as a surplus battery cluster, and obtaining a second charging / discharging power of the surplus battery cluster according to a preset power extreme value.

[0116] Step 24: operating the battery cluster as a non-excess battery cluster, and obtaining a second charging / discharging power of the non-excess battery cluster according to the ideal power value.

[0117] Based on the method described in steps 21 to 24 above, power allocation can be performed more reasonably while taking into account the charging / discharging power extremes of the operating battery cluster and the power extremes of the DC / DC.

[0118] In some embodiments, for the excess battery cluster, it is impossible to completely allocate the ideal power value of the excess battery cluster to the excess battery cluster, so some power will remain after the allocation. In this regard, the remaining power can be reallocated to the non-excess battery cluster. Specifically, the power can be reallocated to the non-excess battery cluster through the following steps 31 to 33.

[0119] Step 31: Obtain the power difference between the ideal power value of the excess battery cluster and the preset power limit value, which is the power remaining after the allocation is completed.

[0120] Step 32: Obtain the remaining charge / discharge power according to the power difference of all excess battery clusters. Specifically, the sum of the power difference of all excess battery clusters can be used as the remaining charge / discharge power.

[0121] Step 33: According to the remaining charge / discharge power and the power allocation ratio of the non-excess battery cluster, power is allocated to the non-excess battery cluster again. The method of allocating power to the non-excess battery cluster again is the same as the power allocation method in the above embodiment.

[0122] For example: There are four operating battery clusters 1-4 in the battery stack, and the SOCs of these four operating battery clusters 1-4 are: SOC1=20%, SOC2=40%, SOC1=60%, SOC1=80%; the ideal power values ​​of these four operating battery clusters 1-4 during discharge are: 0.1×Pd, 0.2×Pd, 0.3×Pd, 0.4×Pd. If the preset power extreme value is 0.25×Pd, then the second discharge powers allocated to these four operating battery clusters 1-4 are: 0.1×Pd, 0.2×Pd, 0.25×Pd, 0.25×Pd, respectively. Operating battery clusters 1 and 2 are not over-rated battery clusters, and operating battery clusters 3 and 4 are over-rated battery clusters. At this time, the remaining discharge power is 0.2×Pd, and 0.2×Pd is allocated to operating battery clusters 1 and 2 again.

[0123] Based on the methods described in steps 31 to 33 above, when the excess battery cluster has allocated the remaining storage power, power can be allocated again to the non-excess battery cluster, so that the energy storage subsystem can accurately and reliably complete charging / discharging according to the first charging / discharging power of the battery stack.

[0124] 2. Explain step S103.

[0125] In some embodiments of the above step S103, the energy storage subsystem includes a power conversion system PCS (Power Convert System), the first DC side of the DC / DC is connected to the DC bus of the power conversion system PCS, and the second DC side of the DC / DC is connected to the battery cluster. Figure 4 The following steps S1031 to S1033 shown control the DC / DC corresponding to the operating battery cluster to charge / discharge the operating battery cluster.

[0126] Step S1031: determining a target charging / discharging current of the DC / DC corresponding to the operating battery cluster according to the second charging / discharging power of the operating battery cluster and the voltage of the DC bus.

[0127] In this implementation, the target charging / discharging current of the DC / DC can be obtained according to the second charging / discharging power and the voltage of the DC bus while keeping the voltage of the DC bus unchanged.

[0128] Step S1032: using a droop control method, according to the target charge / discharge current of the DC / DC, determining the droop control parameters of the DC / DC, the droop control parameters including the virtual resistance of the DC / DC.

[0129] In this embodiment, a conventional droop control method may be used to determine the virtual resistance of the DC / DC according to the target charge / discharge current of the DC / DC.

[0130] Step S1033: adopting a droop control method to adjust the actual charging / discharging current of the DC / DC according to the virtual resistance so that the actual charging / discharging current is the same as the target charging / discharging current.

[0131] In this embodiment, a conventional droop control method may be used to adjust the actual charging / discharging current of the DC / DC according to the virtual resistance.

[0132] During charging, the output current of the second DC side of the DC / DC (the DC side connected to the battery cluster) is controlled according to the actual charging current of the DC / DC, so that the external electric energy can be stored in the operating battery cluster through the DC / DC to achieve charging. During discharging, the output current of the second DC side of the DC / DC is controlled according to the actual discharge current of the DC / DC, so that the battery cluster can discharge outward through the DC / DC. In addition, since the actual charging / discharging current of the DC / DC is obtained based on the virtual resistance, and the virtual resistance is determined without affecting or changing the above-mentioned DC bus voltage, therefore, during the charging / discharging process of the operating battery cluster, the operating battery cluster can be charged / discharged according to the allocated charging / discharging power without affecting or changing the above-mentioned DC bus voltage.

[0133] In some embodiments, if the target charge / discharge current exceeds the charge / discharge current limit of the DC / DC, the actual charge / discharge current of the DC / DC is adjusted to the charge / discharge current limit. That is, if the target charge / discharge current exceeds the control range of the actual charge / discharge current by the droop control, the actual charge / discharge current of the DC / DC is adjusted to the charge / discharge current limit. The charge / discharge current limit is one of the parameters of the DC / DC, and different DC / DCs may have different charge / discharge current limits. In this embodiment, the charge / discharge current limit can be directly obtained according to the parameter information of the DC / DC.

[0134] Based on the method described in steps S1031 to S1033 above, a droop control method can be used to conveniently and reliably control the DC / DC to charge / discharge the operating battery cluster.

[0135] 3. Explain step S104.

[0136] In some implementations of the above step S104, Figure 5 The following steps S1041 to S1044 are used to determine a first battery cluster that needs to be recharged and a second battery cluster that does not need to be recharged.

[0137] Step S1041: Obtain a balancing target value according to an average value of the state of charge (SOC) of all battery clusters in the battery stack. Specifically, the average value may be used as the balancing target value.

[0138] Step S1042: Determine whether the state of charge (SOC) of the battery cluster is less than the balancing target value.

[0139] The balancing target value may represent the average energy of the entire battery stack. If the state of charge SOC of the battery cluster is less than the balancing target value, it indicates that the remaining energy of the battery cluster is less than the average energy and the battery cluster needs to be recharged. Therefore, the process proceeds to step S1043 to determine that the battery cluster is the first battery cluster. If the state of charge SOC of the battery cluster is greater than or equal to the balancing target value, it indicates that the remaining energy of the battery cluster is greater than or equal to the average energy and the battery cluster does not need to be recharged. Therefore, the process proceeds to step S1044 to determine that the battery cluster is the second battery cluster.

[0140] Step S1043: The battery cluster is the first battery cluster that needs to be recharged.

[0141] Step S1044: the battery cluster is a second battery cluster that does not need to be recharged.

[0142] Based on the method described in steps S1041 to S1044, the average value of the state of charge (SOC) of all battery clusters in the battery stack can be used to quickly and accurately determine the first battery cluster that needs to be recharged and the second battery cluster that does not need to be recharged.

[0143] 4. Explain step S105.

[0144] In some embodiments of the above step S105, the energy storage subsystem includes a power conversion system PCS, the first DC side of the DC / DC is connected to the DC bus of the power conversion system PCS, and the second DC side of the DC / DC is connected to the battery cluster. Figure 6 The following steps S1051 to S1052 are used to control the mutual charging and discharging between the first battery cluster and the second battery cluster.

[0145] Step S1051: controlling the DC / DC corresponding to the second battery cluster to operate in a discharge mode, so as to control the second battery cluster to discharge through the DC bus of the power conversion system PCS.

[0146] Step S1052: Control the DC / DC corresponding to the first battery cluster to operate in a charging mode, so as to control the first battery cluster to be charged via the DC bus of the power conversion system PCS.

[0147] Based on the method described in steps S1051 to S1052, the DC bus of the power conversion system PCS can be used as an energy conversion channel between the first and second battery clusters, so that the first and second battery clusters can be charged and discharged mutually.

[0148] In some implementations, the DC / DC corresponding to the first battery cluster may be controlled to operate in a constant voltage charging mode, and the DC / DC corresponding to the second battery cluster may be controlled to operate in a constant current discharging mode.

[0149] In some implementations, the DC / DC corresponding to the first battery cluster may be controlled to operate in a constant current charging mode, and the DC / DC corresponding to the second battery cluster may be controlled to operate in a constant voltage discharging mode.

[0150] The constant voltage charging mode, constant current charging mode, constant voltage discharging mode, and constant current discharging mode are all conventional charging / discharging modes in the field of battery technology, and the working principles of these modes are not described in detail in this embodiment.

[0151] It should be pointed out that although the various steps in the above embodiments are described in a specific order, those skilled in the art can understand that in order to achieve the effect of the present application, different steps do not have to be executed in such an order. They can be executed simultaneously (in parallel) or in other orders. These adjusted schemes are equivalent to the technical schemes described in this application, and therefore will also fall within the scope of protection of this application.

[0152] It is understood by those skilled in the art that all or part of the processes in the method for implementing the above-mentioned embodiment of the present application can also be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable storage medium may include: any entity or device, medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory, random access memory, electrical carrier signal, telecommunication signal and software distribution medium, etc. that can carry the computer program code.

[0153] Another aspect of the present application also provides a computer-readable storage medium.

[0154] In an embodiment of a computer-readable storage medium according to the present application, the computer-readable storage medium may be configured to store a program for executing the energy management method of the energy storage system of the above-mentioned method embodiment, and the program may be loaded and run by the processor to implement the energy management method of the above-mentioned energy storage system. For ease of explanation, only the parts related to the embodiment of the present application are shown. For specific technical details not disclosed, please refer to the method part of the embodiment of the present application. The computer-readable storage medium may be a storage device formed by various electronic devices. Optionally, the computer-readable storage medium in the embodiment of the present application is a non-temporary computer-readable storage medium.

[0155] Another aspect of the present application provides an electronic device.

[0156] In an embodiment of an electronic device according to the present application, the electronic device may include at least one processor; and a memory connected to the at least one processor in communication; wherein a computer program is stored in the memory, and when the computer program is executed by the at least one processor, the method described in any of the above embodiments is implemented. Figure 7 , Figure 7 FIG. 4 exemplarily shows that the memory 11 and the processor 12 are communicatively connected via a bus.

[0157] Another aspect of the present application also provides an energy storage system.

[0158] In an embodiment of an energy storage system according to the present application, the energy storage system includes an energy management system EMS and an energy storage subsystem. The energy management system EMS is used to execute the energy management method of the energy storage system described in the above method embodiment.

[0159] The energy storage subsystem includes a battery management system BMS, a battery stack and multiple DC / DCs. The battery stack includes multiple battery clusters. The battery management system BMS includes multiple battery management units BCU. The multiple battery management units BCU correspond one-to-one to the multiple battery clusters, and the multiple DC / DCs correspond one-to-one to the multiple battery clusters.

[0160] In some embodiments, the battery management system BMS also includes a main battery management unit BAU (Battery Array Unit) and multiple battery collection and balancing units BMU (Battery Management Unit), and the battery cluster may include multiple battery groups. Multiple battery collection and balancing units BMU correspond one-to-one to the battery groups in the battery stack. The battery collection and balancing unit BMU, the battery management unit BCU, and the main battery management unit BAU form a three-level management architecture. The main battery management unit BAU is used to manage the battery stack, the battery management unit BCU is used to manage the battery cluster, and the battery collection and balancing unit BMU is used to manage the battery group.

[0161] The following is combined with Figure 8 and attached Fig. 9 , a comparative description of the prior art and the energy storage system provided in this application.

[0162] First, refer to the attached Figure 8 , Figure 8 The main structure of the energy storage system in the prior art is shown as an example. Figure 8 As shown, the energy storage system includes an energy management system EMS and an energy storage subsystem. The energy storage subsystem includes a battery stack, a power conversion system PCS, a battery management system BMS, temperature and humidity sensors, fire flammable controllers, air conditioners, etc. The battery management system BMS includes a master battery management unit BAU, 8 slave battery management units BCU, and 152 battery acquisition and balancing units BMU. The battery stack includes 8 battery clusters, each battery cluster includes 19 battery groups, that is, the battery stack has a total of 152 battery groups. The 8 slave battery management units BCU correspond one-to-one to the 8 battery clusters, and the 152 battery acquisition and balancing units BMU correspond one-to-one to the 152 battery groups. In addition, the battery management system BMS also includes a high-voltage line control unit, an energy storage cabinet pre-charging (parallel) line, a high-voltage detection unit, a thermal management unit, a current detection unit, an emergency stop system, and a battery monitoring system, etc. ( Figure 8 (Not shown). The battery management system BMS is used to detect the voltage, temperature and total current of the single battery in the battery cluster, calculate the battery SOC of the battery cluster, store the relevant battery cluster manufacturing information, version information and necessary operation history data, and each unit of the battery management system BMS communicates in real time through the CAN bus. Each level transmits the battery operation status and alarm information of the battery cluster to the upper management system, and each level receives the operation instructions issued by the upper management system in real time. The battery management system BMS can automatically perform high voltage and thermal management, and coordinate the automatic balancing function of the entire battery stack.

[0163] The battery management system BMS also includes 8 high-voltage control boxes, etc. The 8 high-voltage control boxes correspond to the 8 battery clusters one by one. The high-voltage control boxes include circuit breakers, fuses, etc. The high-voltage control boxes are used to convert and store energy for the battery clusters. However, the high-voltage control boxes have the disadvantages of poor safety and low efficiency when working, which will reduce the storage efficiency of the entire energy storage system. At the same time, the above energy storage system can only replenish the battery clusters by artificial replenishment to balance the energy between the battery clusters.

[0164] See attached Fig. 9 , Fig. 9 The main structure of the energy storage subsystem according to one embodiment of the present application is exemplified. Fig. 9 As shown, the energy storage subsystem includes a power conversion system PCS, a main battery management unit BAU, and two battery management units BCU (i.e. Fig. 9BCU_1-2 and BCU_3-4 shown), 8 battery collection and balancing units BMU, two DC / DCs, and a battery stack. The battery stack includes two battery clusters, each battery cluster includes 4 battery groups, that is, the battery stack has a total of 8 battery groups. The two battery management units BCU correspond one-to-one to the two battery clusters, the two DC / DCs also correspond one-to-one to the two DC / DCs, and the 8 battery collection and balancing units BMU correspond one-to-one to the 8 battery groups. The energy management system EMS, the power conversion system PCS, the main battery management unit BAU, and the DC / DC are respectively connected to the switch through network cables. The DC / DC is also connected to the power conversion system PCS through a DC power line. The main battery management unit BAU, the battery management unit BCU, and the battery collection and balancing unit BMU are connected in sequence through the CAN bus. Among them, the energy management system EMS can execute the energy management method described in the aforementioned method embodiment.

[0165] Based on the above structure, when the energy storage subsystem is running (the power conversion system PCS is not shut down), the DC / DC can be used to control the charge and discharge of the running battery cluster. Compared with the high-voltage control box, the safety and efficiency of the charge and discharge control can be guaranteed, and the storage efficiency of the energy storage subsystem can be improved. When the energy storage subsystem is not running (the power conversion system PCS is shut down), the DC / DC can be used to automatically supplement the battery cluster to balance the energy between the battery clusters.

[0166] So far, the technical solution of the present application has been described in conjunction with an embodiment shown in the accompanying drawings, but it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present application.

Claims

1. An energy management method for an energy storage system, wherein the energy storage system comprises an energy management system EMS and an energy storage subsystem, wherein the energy storage subsystem comprises a battery management system BMS and a battery stack, wherein the battery stack comprises a plurality of battery clusters, wherein the battery management system BMS comprises a plurality of battery management units BCU, wherein the plurality of battery management units BCU correspond to the plurality of battery clusters one by one, and wherein: The energy storage subsystem further includes a plurality of DC / DCs, and the plurality of DC / DCs correspond to the plurality of battery clusters one by one. The method is applied to the energy management system EMS, and the method includes: When the energy storage subsystem is running, power is allocated to the running battery cluster according to the first charging / discharging power of the battery stack and the state of charge SOC of the running battery cluster in the battery stack to determine the second charging / discharging power of the running battery cluster; and the DC / DC corresponding to the running battery cluster is controlled according to the second charging / discharging power to charge / discharge the running battery cluster; When the energy storage subsystem is not in operation, a first battery cluster that needs to be recharged and a second battery cluster that does not need to be recharged are determined according to the state of charge (SOC) of each battery cluster in the battery stack; and mutual charging and discharging between the first battery cluster and the second battery cluster are controlled through the DC / DC corresponding to the first battery cluster and the second battery cluster until the state of charge (SOC) of the first battery cluster and the second battery cluster are the same.

2. The method according to claim 1, characterized in that The determining, according to the state of charge SOC of each battery cluster in the battery stack, a first battery cluster that needs to be supplemented with electricity and a second battery cluster that does not need to be supplemented with electricity comprises: Obtaining a balancing target value according to an average value of the state of charge (SOC) of all battery clusters in the battery stack; If the state of charge (SOC) of the battery cluster is less than the balancing target value, the battery cluster is a first battery cluster that needs to be recharged; if the state of charge (SOC) of the battery cluster is greater than or equal to the balancing target value, the battery cluster is a second battery cluster that does not need to be recharged.

3. The method according to claim 1, characterized in that The energy storage subsystem includes a power conversion system PCS, a first DC side of the DC / DC is connected to a DC bus of the power conversion system PCS, a second DC side of the DC / DC is connected to the battery cluster, and the mutual charging and discharging between the first battery cluster and the second battery cluster is controlled by the DC / DC corresponding to the first battery cluster and the second battery cluster, including: Controlling the DC / DC corresponding to the second battery cluster to operate in a discharge mode, so as to control the second battery cluster to discharge through the DC bus of the power conversion system PCS; The DC / DC corresponding to the first battery cluster is controlled to operate in a charging mode, so as to control the first battery cluster to be charged via the DC bus of the power conversion system PCS.

4. The method according to claim 3, characterized in that The method further comprises: Controlling the DC / DC corresponding to the first battery cluster to operate in a constant voltage charging mode, and controlling the DC / DC corresponding to the second battery cluster to operate in a constant current discharging mode; or, The DC / DC corresponding to the first battery cluster is controlled to operate in a constant current charging mode, and the DC / DC corresponding to the second battery cluster is controlled to operate in a constant voltage discharging mode.

5. The method according to claim 1, characterized in that The method of allocating power to the operating battery cluster according to the first charging / discharging power of the battery stack and the state of charge SOC of the operating battery cluster in the battery stack includes: Obtaining a battery stack SOC of the battery stack, where the battery stack SOC is the sum of the states of charge SOCs of all operating battery clusters in the battery stack; Respectively obtaining a SOC ratio between the state of charge SOC of each of the operating battery clusters and the SOC of the battery stack, and obtaining a power allocation ratio of the operating battery cluster according to the SOC ratio of the operating battery cluster; Power is distributed to the operating battery cluster according to the first charge / discharge power of the battery stack and the power distribution ratio of the operating battery cluster.

6. The method according to claim 5, characterized in that The obtaining the power allocation ratio of the operating battery cluster according to the SOC ratio of the operating battery cluster includes: When the first charging / discharging power and the second charging / discharging power are both discharging powers, the SOC ratio of the operating battery cluster is used as the power allocation ratio of the operating battery cluster; When the first charging / discharging power and the second charging / discharging power are both charging powers, the operating battery clusters are sorted in descending order of the state of charge SOC to form a battery cluster sequence, the SOC ratios of the operating battery clusters are sorted in descending order to form an SOC ratio sequence, and the i-th SOC ratio in the SOC ratio sequence is used as the power allocation ratio of the j-th operating battery cluster in the battery cluster sequence, i=j.

7. The method according to claim 5, characterized in that The step of allocating power to the operating battery cluster according to the first charge / discharge power of the battery stack and the power allocation ratio of the operating battery cluster includes: acquiring an ideal power value of the operating battery cluster according to a product of the first charging / discharging power and the power allocation ratio of the operating battery cluster; If the ideal power value is greater than or equal to the preset power extreme value, the operating battery cluster is an excess battery cluster, and a second charging / discharging power of the excess battery cluster is obtained according to the preset power extreme value; If the ideal power value is less than the preset power extreme value, the operating battery cluster is a non-excess battery cluster, and a second charging / discharging power of the non-excess battery cluster is obtained according to the ideal power value; in, The preset power limit is a charging / discharging power limit of the operating battery cluster or the preset power limit is a power limit of a DC / DC corresponding to the operating battery cluster.

8. The method according to claim 7, characterized in that The method further comprises: Obtaining a power difference between an ideal power value of the excess battery cluster and the preset power extreme value; Obtaining the remaining charging / discharging power according to the power difference of all excess battery clusters; Power is again allocated to the non-excess battery cluster according to the remaining charge / discharge power and the power allocation ratio of the non-excess battery cluster.

9. The method according to claim 1, characterized in that: The energy storage subsystem includes a power conversion system PCS, a first DC side of the DC / DC is connected to a DC bus of the power conversion system PCS, a second DC side of the DC / DC is connected to the battery cluster, and the DC / DC corresponding to the operating battery cluster is controlled according to the second charging / discharging power to charge / discharge the operating battery cluster, including: Determining a target charging / discharging current of a DC / DC corresponding to the operating battery cluster according to a second charging / discharging power of the operating battery cluster and a voltage of the DC bus; Adopting a droop control method, determining a droop control parameter of the DC / DC according to a target charge / discharge current of the DC / DC, wherein the droop control parameter includes a virtual resistance of the DC / DC; and, An actual charge / discharge current of the DC / DC is adjusted according to the virtual resistance so that the actual charge / discharge current is the same as the target charge / discharge current.

10. The method according to claim 9, characterized in that The method further comprises: If the target charge / discharge current exceeds the charge / discharge current limit of the DC / DC, the actual charge / discharge current of the DC / DC is adjusted to the charge / discharge current limit.

11. An energy storage system, comprising an energy management system EMS and an energy storage subsystem, wherein the energy storage subsystem comprises a battery management system BMS and a battery stack, wherein the battery stack comprises a plurality of battery clusters, wherein the battery management system BMS comprises a plurality of battery management units BCU, wherein the plurality of battery management units BCU correspond to the plurality of battery clusters one by one, and wherein: The energy storage subsystem further includes a plurality of DC / DCs, and the plurality of DC / DCs correspond one-to-one to the plurality of battery clusters; The energy management system EMS is used to execute the energy management method of the energy storage system according to any one of claims 1 to 10.

12. An electronic device, characterized in that: include: at least one processor; and, a memory communicatively coupled to the at least one processor; The memory stores a computer program, and when the computer program is executed by the at least one processor, the energy management method for the energy storage system according to any one of claims 1 to 10 is implemented.

13. A computer-readable storage medium storing a plurality of program codes, characterized in that: The program code is suitable for being loaded and run by a processor to execute the energy management method for an energy storage system according to any one of claims 1 to 10.

Images