A battery cluster SOC balancing control method and device for energy storage system

Abstract

The present application discloses a battery cluster SOC balancing control method and device for an energy storage system. The method of the present invention sets two balancing control strategies to achieve SOC coarse adjustment and fine adjustment. The first balancing control strategy achieves SOC balancing within the battery cluster: coarsely adjusts the system SOC, and dynamically adjusts the charge and discharge power of each battery cell in high and low segments based on the SOC standard deviation of the single battery cells in the battery cluster, so that the power of all battery cells is roughly consistent, achieving SOC balance within the battery cluster, avoiding overcharging or undercharging of the single cells, reducing the risk of thermal runaway, and extending the life of the battery cluster; the second balancing control strategy achieves SOC balancing between battery clusters: finely adjusts the system SOC, and dynamically adjusts the charge and discharge power of each target battery cluster based on the standard deviation of the SOC of the target battery cluster, so that the SOC of each battery cluster is basically consistent, the battery clusters are used in the best way, and the system is in the best working state, thereby improving the life of the system battery cluster.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage systems, and in particular relates to a battery cluster SOC balancing control method and device for an energy storage system. Background Art

[0002] Energy storage has shifted from backup to primary use and has become an asset that generates income. The charging and discharging capabilities of battery clusters in energy storage systems have become a core demand. Energy storage systems are usually composed of battery systems, energy storage converters PCS, and energy storage monitoring systems EMS. Among them, the battery system includes a battery stack and a battery management system BMS. The battery stack is formed by a number of battery cells connected in series or in series and parallel to form a battery group. Several battery groups are connected in series to form a battery cluster, and then several battery clusters are connected in parallel to form a battery stack. The battery management system BMS is used to manage each battery cell in the battery stack so that the state of charge SOC of each battery cell is basically consistent and maintains a balanced state.

[0003] At present, in the application of energy storage systems where multiple battery clusters are used in parallel, with the cyclic use of the battery system, the SOC difference problem between battery clusters caused by the attenuation of battery capacity has become increasingly prominent, which will lead to a decline in system performance, or even unusability, requiring shutdown for maintenance, which will bring downtime risks or loss of revenue in power operations to customers. In the prior art, the balancing relationship technology only adjusts the battery clusters in the battery pack during the adjustment of the battery pack, but cannot manage and adjust the battery cells more finely, which will cause the SOC of each battery cell in the battery cluster to be inconsistent, and the SOC imbalance between battery cells will seriously affect the balance of the SOC between battery clusters, thereby affecting the overall SOC balance of the energy storage system, and ultimately causing problems such as low service life and poor balance performance of the energy storage system.

[0004] Therefore, how to design a fast and dynamic SOC parallel balancing method between battery clusters and battery cells is a technical problem to be solved. Summary of the invention

[0005] Based on this, it is necessary to provide a battery cluster SOC balancing control method for an energy storage system to address the existing problems, including the following steps:

[0006] S1: Obtaining cluster SOCs of multiple battery clusters of the energy storage system and single-cell SOCs of multiple battery cells in each battery cluster, obtaining a cluster SOC data set consisting of multiple cluster SOCs and multiple single-cell SOC data sets consisting of single-cell SOCs including multiple battery cells;

[0007] S2: obtaining a system average SOC of the energy storage system and a plurality of average SOCs of cells of a plurality of battery clusters according to the cluster SOC data set and the plurality of cell SOC data sets;

[0008] S3: determining whether the absolute difference between the cluster SOC in the cluster SOC data set and the system average SOC is greater than a first SOC threshold;

[0009] S4: in response to the absolute difference between the cluster SOC in the cluster SOC data set and the system average SOC being greater than a first SOC threshold, the battery cluster that meets this condition is recorded as a target battery cluster, and all target battery clusters constitute a target battery cluster set;

[0010] S5: determining whether the absolute difference between the average value of the maximum SOC and the minimum SOC of the cells of the target battery cluster in the target battery cluster set and the average SOC of the cells is greater than a second SOC threshold;

[0011] S6: in response to the absolute difference between the average value of the maximum SOC and the minimum SOC of the cells of the target battery cluster in the target battery cluster set and the average SOC of the cells being greater than a second SOC threshold, performing SOC balancing inside the target battery cluster using a first balancing control strategy;

[0012] S7: updating the cluster SOC data set and determining whether the cluster SOCs in the cluster SOC data set are consistent;

[0013] S8: In response to the cluster SOCs in the cluster SOC data set being inconsistent, adopting a second balancing control strategy to balance the SOCs between the battery clusters of the energy storage system.

[0014] Preferably, the first SOC threshold is expressed by formula (1):

[0015] ;

[0016] in, is the first SOC threshold, is the first adjustment coefficient, N is the total number of battery clusters in the energy storage system, is the standard deviation of the SOC values ​​of all battery clusters, It is expressed by formula (2):

[0017] ;

[0018] in, is the system average SOC, is the cluster SOC data set The cluster SOC of the battery cluster.

[0019] Preferably, the second SOC threshold is expressed by formula (3):

[0020] ;

[0021] in, is the second SOC threshold, is the second adjustment coefficient, For the The standard deviation of the cluster SOC values ​​of the battery clusters, It is expressed by formula (4):

[0022] ;

[0023] in, For the The average SOC of the cells in the battery cluster, For the The battery cluster The single SOC of each battery cell, is the total number of battery cells in a battery cluster, and A is the total number of battery clusters in the target battery cluster.

[0024] Preferably, a first balancing control strategy is adopted to balance the SOC inside the target battery cluster, including:

[0025] According to the single-cell SOC data set of the target battery cluster, all battery cells are divided into a high SOC segment set and a low SOC segment set according to their SOC values;

[0026] Energy is transferred from the battery cells corresponding to the high SOC segment set to the battery cells corresponding to the low SOC segment set until SOC balance is achieved inside the target battery cluster.

[0027] Preferably, a second balancing control strategy is used to balance the SOC between the battery clusters of the energy storage system, including:

[0028] The cluster SOC data sets are sorted from small to large to obtain a cluster SOC standard data set, and the battery clusters corresponding to the cluster SOC standard data set are numbered as: standard battery cluster 1, standard battery cluster 2, ... standard battery cluster N ;

[0029] Determine whether the energy storage system is currently in charging mode or discharging mode;

[0030] In response to the energy storage system being in a charging mode, charging all battery clusters according to a preset charging strategy;

[0031] In response to the energy storage system being in the discharge mode, all battery clusters are discharged according to a preset discharge strategy.

[0032] Preferably, all battery clusters are charged according to a preset charging strategy, including:

[0033] The power obtained by the battery cluster of the energy storage system according to formula (5) Charging;

[0034] ;

[0035] in, is the maximum power of the PCS of the energy storage system, Standard battery cluster for cluster SOC standard data set The cluster SOC, is the cluster maximum SOC of the cluster SOC standard data set.

[0036] Preferably, all battery clusters are discharged according to a preset discharge strategy, including:

[0037] The power obtained by the battery cluster of the energy storage system according to formula (6) Discharge is performed;

[0038] ;

[0039] in, is the maximum power of the PCS of the energy storage system, Standard battery cluster for cluster SOC standard data set The cluster SOC, is the cluster maximum SOC of the cluster SOC standard data set.

[0040] Preferably, the first adjustment coefficient is related to the temperature, internal resistance, aging degree, charging rate and expected discharge depth of the energy storage system.

[0041] Preferably, the second adjustment coefficient is related to the temperature, internal resistance, aging degree, charging rate and expected discharge depth of the battery cluster of the energy storage system.

[0042] In a second aspect, an embodiment of the present application discloses a battery cluster SOC balancing control device of an energy storage system, comprising:

[0043] A data acquisition module, used to acquire the cluster SOC of multiple battery clusters of the energy storage system and the single cell SOC of multiple battery cells in each battery cluster, and obtain a cluster SOC data set consisting of multiple cluster SOCs and multiple single cell SOC data sets consisting of single cell SOCs containing multiple battery cells;

[0044] A data calculation module, used for obtaining a system average SOC of the energy storage system and a plurality of average SOCs of cells of a plurality of battery clusters according to the cluster SOC data set and the plurality of cell SOC data sets;

[0045] A first judgment module, configured to judge whether an absolute difference between the cluster SOC in the cluster SOC data set and the system average SOC is greater than a first SOC threshold;

[0046] a data processing module, configured to, in response to an absolute difference between the cluster SOC in the cluster SOC data set and the system average SOC being greater than a first SOC threshold, record the battery cluster that meets the condition as a target battery cluster, and all target battery clusters constitute a target battery cluster set;

[0047] A second judgment module, used to judge whether the absolute difference between the average value of the maximum SOC and the minimum SOC of the cells of the target battery cluster in the target battery cluster set and the average SOC of the cells is greater than a second SOC threshold;

[0048] A first balancing module, configured to, in response to an absolute difference between an average value of a maximum SOC and a minimum SOC of a single cell of a target battery cluster in the target battery cluster set and a single cell average SOC being greater than a second SOC threshold, adopt a first balancing control strategy to perform SOC balancing inside the target battery cluster;

[0049] A data updating module, used for updating the cluster SOC data set and determining whether the cluster SOCs in the cluster SOC data set are consistent;

[0050] The second balancing module is configured to, in response to inconsistency in the cluster SOCs in the cluster SOC data set, adopt a second balancing control strategy to balance the SOCs between the battery clusters of the energy storage system.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] (1) Two balancing control strategies are set to achieve coarse and fine adjustment of the SOC of the energy storage system battery, so that the system can quickly achieve SOC balancing to ensure that the system battery always works in the best state, thereby reducing damage to the battery and extending the battery life;

[0053] (2) The first balancing control strategy realizes SOC balancing within the battery cluster: the SOC within the battery cells of the battery cluster is adjusted, that is, the SOC of the energy storage system is roughly adjusted. The control strategy dynamically adjusts the charge and discharge power of each battery cell in high and low segments based on the standard deviation of the SOC of the battery cell of the battery cluster, so that the power of all battery cells remains roughly consistent, achieving SOC balance within the battery cluster, avoiding overcharging or undercharging of battery cells, helping to improve charging and discharging efficiency, reduce the risk of thermal runaway, and further extend the life of the battery cluster; at the same time, balancing the single cells can more effectively utilize the energy of the battery cluster, ensuring that each battery cluster can reach its maximum storage capacity, thereby improving the energy utilization rate of the entire energy storage system;

[0054] (3) The second balancing control strategy achieves SOC balancing between battery clusters: The second balancing control strategy is used to adjust the SOC between the battery clusters of the energy storage system, that is, to finely adjust the SOC of the energy storage system. This control strategy dynamically adjusts the charge and discharge power of each target battery cluster based on the standard deviation of the target battery cluster SOC, so that the SOC of each battery cluster is basically consistent, so that the battery clusters have the same usage time and the same usage environment, and multiple battery clusters can be used in the best way, so that the battery is not easily damaged and the life of the system battery cluster is improved; the SOC of multiple battery clusters is consistent, which maximizes the system charge and discharge power, maximizes the utilization of electrical energy, reduces energy damage, and saves energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] By referring to the following drawings, the exemplary embodiments of the present invention can be more completely understood. The drawings are used to provide a further understanding of the embodiments of the present application, and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present invention and do not constitute a limitation of the present invention. In the drawings, the same reference numerals generally represent the same parts or steps.

[0056] Figure 1 A flowchart of a battery cluster SOC balancing control method for an energy storage system provided according to an exemplary embodiment of the present application;

[0057] Figure 2 The present invention is a schematic structural diagram of a battery cluster SOC balancing control device for an energy storage system according to an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0058] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0059] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0060] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0061] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0062] Example 1

[0063] like Figure 1 As shown, the embodiment of the present application provides a battery cluster SOC balancing control method of an energy storage system, comprising the following steps:

[0064] S1: Obtain the cluster SOCs of multiple battery clusters of the energy storage system and the single-cell SOCs of multiple battery cells in each battery cluster, and obtain a cluster SOC data set consisting of multiple cluster SOCs and a multiple single-cell SOC data set consisting of single-cell SOCs including multiple battery cells;

[0065] Specifically, the energy storage system includes a PCS module, battery clusters (battery cluster 1, battery cluster 2, ... battery cluster 10, in this embodiment, only battery cluster as an example), each battery cluster contains Battery cells (in this embodiment, only Before the method starts, data is obtained through the control units of each battery cluster, and the data of each battery cluster is obtained through the control unit of the energy storage system for subsequent retrieval and use.

[0066] In this embodiment, the cluster SOC data of battery clusters 1 to 10 are obtained, that is, the cluster SOC data set includes: , ,……, ; Among them, the SOC data of each battery cell of battery cluster 1 is: , , , , and , which is the first monomer SOC data set, the The monomer data set is: , , , , and , .

[0067] S2: obtaining a system average SOC of the energy storage system and a plurality of average SOCs of cells of a plurality of battery clusters according to a cluster SOC data set and a plurality of cell SOC data sets;

[0068] Specifically, the system average SOC is calculated based on the data obtained in the previous steps ( ) and the average SOC of multiple cells in multiple battery clusters ( ).

[0069] Specifically, , .

[0070] S3: Determine whether the absolute difference between the cluster SOC in the cluster SOC data set and the system average SOC is greater than a first SOC threshold;

[0071] Specifically, due to the long-term use of battery clusters, their own performance will vary. For battery clusters with better performance and lower aging, their SOC balancing thresholds can be set relatively high to allow for greater SOC differences. For battery clusters with poorer performance and higher aging, their SOC balancing thresholds can be set relatively low. Therefore, the dynamic SOC balancing threshold is set to a range value to ensure the safety of the battery cluster, thereby ensuring the stable operation of the energy storage system.

[0072] In this embodiment, it is necessary to judge ( ) is greater than the first SOC threshold.

[0073] Specifically, the first SOC threshold is expressed by formula (1):

[0074] ;

[0075] in, is the first SOC threshold, is the first adjustment coefficient, is the standard deviation of cluster SOC of all battery clusters, It is expressed by formula (2):

[0076] .

[0077] Specifically, the first adjustment coefficient It is a tolerance factor, which is related to the current temperature, internal resistance, aging degree, charging rate and expected discharge depth of the energy storage system. Its purpose is to dynamically adjust the SOC balance threshold of the energy storage system to ensure that the energy storage system operates in the best working state.

[0078] S4: in response to the absolute difference between the cluster SOC in the cluster SOC data set and the system average SOC being greater than a first SOC threshold, the battery cluster that meets the condition is recorded as a target battery cluster, and all target battery clusters constitute a target battery cluster set;

[0079] Specifically, the battery clusters that need to be fine-tuned are screened through the cluster SOC values ​​of each battery cluster of the energy storage system, and the selected battery clusters are recorded as target battery clusters, and the SOC data of each battery cell of these battery clusters are synchronously read. In this implementation, it is assumed that the selected battery clusters that meet the S4 limit conditions are: battery cluster 1, battery cluster 2, and battery cluster 3 (only used as an example, there are many different combinations in practice). That is, the target battery cluster set includes: battery cluster 1, battery cluster 2, and battery cluster 3.

[0080] S5: determining whether the absolute difference between the average value of the maximum SOC and the minimum SOC of the cells of the target battery cluster in the target battery cluster set and the average SOC of the cells is greater than a second SOC threshold;

[0081] Specifically, after the target battery clusters are screened out, each battery cluster is further determined to determine which battery clusters need fine-tuning. This is because the battery cells in the battery cluster are used for a long time, resulting in differences in their own performance. The SOC balancing threshold of the battery cells with better performance and lower aging can be set relatively high to allow for greater SOC differences. For the battery cells with poorer performance and higher aging, the SOC balancing threshold can be set relatively low. Therefore, the dynamic SOC balancing threshold is set to a range value to ensure the safety of the battery cells, thereby ensuring the stable operation of the battery cluster.

[0082] In this embodiment, it is necessary to judge ( ) is greater than the second SOC threshold, where: For the The maximum SOC of a single cell in a battery cluster, For the The minimum SOC of a single cell in a battery cluster, For the The average SOC of cells in a battery cluster.

[0083] The second SOC threshold is expressed by formula (3):

[0084] ;

[0085] in, is the second SOC threshold, is the second adjustment coefficient, For the The standard deviation of the cluster SOC of the battery clusters, It is expressed by formula (4):

[0086] ;

[0087] in, For the The battery cluster The single cell SOC of a battery cell.

[0088] Specifically, the second adjustment coefficient It is a tolerance factor, which is related to the current temperature, internal resistance, aging degree, charging rate and expected discharge depth of the battery cluster corresponding to the adjusted battery cell; its purpose is to dynamically adjust the SOC balancing threshold of the battery cluster to ensure that the battery cluster operates in the best working state.

[0089] S6: in response to the absolute difference between the average value of the maximum SOC and the minimum SOC of the cells of the target battery cluster in the target battery cluster set and the average SOC of the cells being greater than the second SOC threshold, performing SOC balancing inside the target battery cluster using the first balancing control strategy;

[0090] Specifically, after the target battery cluster set is screened out, including: battery cluster 1, battery cluster 2 and battery cluster 3, SOC balancing is performed on battery cluster 1, battery cluster 2 and battery cluster 3 according to the first balancing control strategy. The specific process is as follows (the following only takes the adjustment of battery cluster 1 as an example, the adjustment processes of battery cluster 2 and battery cluster 3 are basically the same and will not be repeated here):

[0091] (1) Based on the single cell SOC data set of the battery cluster 1 ( , , , , and ), divide all battery cells into high SOC segment set and low SOC segment set according to SOC value;

[0092] (2) Energy is transferred from the battery cells corresponding to the high SOC segment set to the battery cells corresponding to the low SOC segment set until the battery cluster 1 reaches SOC equilibrium.

[0093] Specifically, the SOC differences between battery cells are monitored in real time, and by comparing the cell SOC values ​​of different battery cells, the battery cells whose state differences exceed the second SOC threshold range are discovered in time, and the first balancing control strategy is used to transfer the energy of the high SOC battery cells to the low SOC battery cells until the SOC of all battery cells reaches the set balancing level. This embodiment ensures that each battery can reach its maximum storage capacity by precisely regulating the single cells, thereby improving the energy utilization of the entire battery pack, improving the charging efficiency, reducing the risk of thermal runaway, and further extending the battery life.

[0094] Specifically, the high SOC and low SOC are the average values ​​of the cluster SOC of all target battery clusters. The division will not be lower than the average The target battery cluster is divided into a high SOC segment set, which is below the average The target battery cluster is divided into a low SOC segment set, and the segmented energy setting method is adopted to effectively avoid the power out-of-bounds situation between battery clusters.

[0095] S7: Update the cluster SOC data set and determine whether the cluster SOCs in the cluster SOC data set are consistent;

[0096] Specifically, after completing the balancing of the SOC within the battery cluster, it is necessary to further determine whether the SOC balance is reached between each battery cluster of the entire energy storage system, so as to make a secondary determination of the system, thereby further ensuring that the SOC of each battery cluster is basically consistent, so that each battery cluster is used for the same time and in the same environment, and multiple battery clusters can be used in the best way, so that the battery cluster is not easily damaged and the life of the system battery cluster is improved.

[0097] Specifically, update the cluster SOC of all battery clusters to obtain a cluster SOC standard data set: , ,……, , and then compare the data in the cluster SOC standard data set to determine whether the system SOC is balanced.

[0098] S8: In response to the inconsistency of the cluster SOCs in the cluster SOC data set, adopting a second balancing control strategy to balance the SOCs between the battery clusters of the energy storage system.

[0099] Specifically, in the above steps, the SOC balance of all battery cells in the battery cluster has been achieved through the first balancing control strategy, that is, the general consistency of the SOC inside the battery cluster has been achieved, that is, the rough adjustment of the system SOC has been completed. In order to further improve the performance of the energy storage system, the present invention also needs to perform a secondary comparison of the SOC data to achieve fine adjustment of the battery cluster SOC, that is, to balance the SOC inside the battery cluster to ensure the consistency of the SOC of multiple clusters of batteries, so that each battery cluster is used for the same time and in the same environment, thereby ensuring that each battery cluster can be used in the best way, ultimately maximizing the system charging and discharging power and maximizing the utilization of electrical energy.

[0100] Specifically, the second balancing control strategy is used to balance the SOC between battery clusters, including:

[0101] (1) Sort the cluster SOC data sets from small to large to obtain the cluster SOC standard data set, and number the battery clusters corresponding to the cluster SOC standard data set as: standard battery cluster 1, standard battery cluster 2, ..., standard battery cluster 10;

[0102] (2) Determine whether the energy storage system is currently in charging mode or discharging mode;

[0103] (3) in response to the energy storage system being in a charging mode, charging all battery clusters according to a preset charging strategy;

[0104] Specifically, all battery clusters are charged according to a preset charging strategy, including:

[0105] The power obtained by the battery cluster of the energy storage system according to formula (5) Charging;

[0106] ;

[0107] in, is the maximum power of the PCS of the energy storage system, Standard battery cluster for cluster SOC standard data set The cluster SOC, is the cluster maximum SOC of the cluster SOC standard data set.

[0108] (4) In response to the energy storage system being in a discharge mode, all battery clusters are discharged according to a preset discharge strategy.

[0109] Specifically, all battery clusters are discharged according to a preset discharge strategy, including:

[0110] The power obtained by the battery cluster of the energy storage system according to formula (6) Discharge is performed;

[0111] ;

[0112] in, is the maximum power of the PCS of the energy storage system, Standard battery cluster for the first SOC standard data set The cluster SOC, is the cluster maximum SOC of the cluster SOC standard data set.

[0113] Compared with the prior art, the present invention has the following beneficial effects:

[0114] (1) Two balancing control strategies are set to achieve coarse and fine adjustment of the SOC of the energy storage system battery, so that the system can quickly achieve SOC balancing to ensure that the system battery always works in the best state, thereby reducing damage to the battery and extending the battery life;

[0115] (2) The first balancing control strategy realizes SOC balancing within the battery cluster: the SOC within the battery cells of the battery cluster is adjusted, that is, the SOC of the energy storage system is roughly adjusted. The control strategy dynamically adjusts the charge and discharge power of each battery cell in high and low segments based on the standard deviation of the SOC of the battery cell of the battery cluster, so that the power of all battery cells remains roughly consistent, achieving SOC balance within the battery cluster, avoiding overcharging or undercharging of battery cells, helping to improve charging and discharging efficiency, reduce the risk of thermal runaway, and further extend the life of the battery cluster; at the same time, balancing the single cells can more effectively utilize the energy of the battery cluster, ensuring that each battery cluster can reach its maximum storage capacity, thereby improving the energy utilization rate of the entire energy storage system;

[0116] (3) The second balancing control strategy achieves SOC balancing between battery clusters: The second balancing control strategy is used to adjust the SOC between the battery clusters of the energy storage system, that is, to finely adjust the SOC of the energy storage system. This control strategy dynamically adjusts the charge and discharge power of each target battery cluster based on the standard deviation of the target battery cluster SOC, so that the SOC of each battery cluster is basically consistent, so that the battery clusters have the same usage time and the same usage environment, and multiple battery clusters can be used in the best way, so that the battery is not easily damaged and the life of the system battery cluster is improved; the SOC of multiple battery clusters is consistent, which maximizes the system charge and discharge power, maximizes the utilization of electrical energy, reduces energy damage, and saves energy.

[0117] Example 2

[0118] This embodiment discloses a battery cluster SOC balancing control device for an energy storage system, which is based on the same inventive concept as the method provided in the previous embodiment of the present application and has the same beneficial effects.

[0119] like Figure 2 As shown, the embodiment of the present application provides a battery cluster SOC balancing control device 20 of an energy storage system, comprising:

[0120] The data acquisition module 201 is used to acquire the cluster SOC of multiple battery clusters of the energy storage system and the single cell SOC of multiple battery cells in each battery cluster, and obtain a cluster SOC data set consisting of multiple cluster SOCs and multiple single cell SOC data sets consisting of single cell SOCs including multiple battery cells;

[0121] A data calculation module 202, configured to obtain a system average SOC of the energy storage system and a plurality of average SOCs of cells of a plurality of battery clusters according to the cluster SOC data set and the plurality of cell SOC data sets;

[0122] A first judgment module 203, configured to judge whether an absolute difference between the cluster SOC in the cluster SOC data set and the system average SOC is greater than a first SOC threshold;

[0123] The data processing module 204 is used for, in response to the absolute difference between the cluster SOC in the cluster SOC data set and the system average SOC being greater than a first SOC threshold, recording the battery cluster that meets the condition as a target battery cluster, and all target battery clusters constitute a target battery cluster set;

[0124] A second judgment module 205 is used to judge whether the absolute difference between the average value of the maximum SOC and the minimum SOC of the cells of the target battery cluster in the target battery cluster set and the average SOC of the cells is greater than a second SOC threshold;

[0125] A first balancing module 206, configured to perform SOC balancing inside the target battery cluster using a first balancing control strategy in response to an absolute difference between an average value of a maximum SOC and a minimum SOC of a single cell of a target battery cluster in the target battery cluster set and a single cell average SOC being greater than a second SOC threshold;

[0126] A data updating module 207, configured to update the cluster SOC data set and determine whether the cluster SOCs in the cluster SOC data set are consistent;

[0127] The second balancing module 208 is configured to, in response to inconsistency in the cluster SOCs in the cluster SOC data set, adopt a second balancing control strategy to balance the SOCs between the battery clusters of the energy storage system.

[0128] It should be noted that the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the systems, methods and computer program products according to multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of the boxes in the block diagram and / or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0129] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0130] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of devices or units can be electrical, mechanical or other forms.

[0131] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0132] 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 it. 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. These modifications or replacements do not deviate the essence of the corresponding technical solutions 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.

Claims

1. A battery cluster SOC balancing control method for an energy storage system, characterized in that: The steps include: S1: Obtaining cluster SOCs of multiple battery clusters of the energy storage system and single-cell SOCs of multiple battery cells in each battery cluster, obtaining a cluster SOC data set consisting of multiple cluster SOCs and multiple single-cell SOC data sets consisting of single-cell SOCs including multiple battery cells; S2: obtaining a system average SOC of the energy storage system and a plurality of average SOCs of cells of a plurality of battery clusters according to the cluster SOC data set and the plurality of cell SOC data sets; S3: determining whether the absolute difference between the cluster SOC in the cluster SOC data set and the system average SOC is greater than a first SOC threshold; S4: in response to the absolute difference between the cluster SOC in the cluster SOC data set and the system average SOC being greater than a first SOC threshold, the battery cluster that meets this condition is recorded as a target battery cluster, and all target battery clusters constitute a target battery cluster set; S5: determining whether the absolute difference between the average value of the maximum SOC and the minimum SOC of the cells of the target battery cluster in the target battery cluster set and the average SOC of the cells is greater than a second SOC threshold; S6: in response to the absolute difference between the average value of the maximum SOC and the minimum SOC of the cells of the target battery cluster in the target battery cluster set and the average SOC of the cells being greater than a second SOC threshold, adopting a first balancing control strategy to perform SOC balancing inside the target battery cluster; S7: updating the cluster SOC data set and determining whether the cluster SOCs in the cluster SOC data set are consistent; S8: In response to the cluster SOCs in the cluster SOC data set being inconsistent, adopting a second balancing control strategy to balance the SOCs between the battery clusters of the energy storage system.

2. The method according to claim 1, characterized in that The first SOC threshold is expressed by formula (1): ； in, is the first SOC threshold, is the first adjustment coefficient, N is the total number of battery clusters in the energy storage system, is the standard deviation of the SOC values ​​of all battery clusters, It is expressed by formula (2): ； in, is the system average SOC, is the cluster SOC data set The cluster SOC of the battery cluster.

3. The method according to claim 2, characterized in that The second SOC threshold is expressed by formula (3): ； in, is the second SOC threshold, is the second adjustment coefficient, For the The standard deviation of the cluster SOC values ​​of the battery clusters, It is expressed by formula (4): ； in, For the The average SOC of the cells in the battery cluster, For the The battery cluster The single SOC of each battery cell, is the total number of battery cells in a battery cluster, and A is the total number of battery clusters in the target battery cluster.

4. The method according to claim 3, characterized in that The first balancing control strategy is used to balance the SOC inside the target battery cluster, including: According to the single-cell SOC data set of the target battery cluster, all battery cells are divided into a high SOC segment set and a low SOC segment set according to their SOC values; Energy is transferred from the battery cells corresponding to the high SOC segment set to the battery cells corresponding to the low SOC segment set until SOC balance is achieved inside the target battery cluster.

5. The method according to claim 4, characterized in that The second balancing control strategy is used to balance the SOC between the battery clusters of the energy storage system, including: The cluster SOC data sets are sorted from small to large to obtain a cluster SOC standard data set, and the battery clusters corresponding to the cluster SOC standard data set are numbered as: standard battery cluster 1, standard battery cluster 2, ... standard battery cluster N ; Determine whether the energy storage system is currently in charging mode or discharging mode; In response to the energy storage system being in a charging mode, charging all battery clusters according to a preset charging strategy; In response to the energy storage system being in the discharge mode, all battery clusters are discharged according to a preset discharge strategy.

6. The method according to claim 5, characterized in that Charge all battery clusters according to the preset charging strategy, including: The power obtained by the battery cluster of the energy storage system according to formula (5) Charging; ； in, is the maximum power of the PCS of the energy storage system, Standard battery cluster for cluster SOC standard data set The cluster SOC, is the cluster maximum SOC of the cluster SOC standard data set.

7. The method according to claim 5, characterized in that Discharge all battery clusters according to the preset discharge strategy, including: The power obtained by the battery cluster of the energy storage system according to formula (6) Discharge is performed; ； in, is the maximum power of the PCS of the energy storage system, Standard battery cluster for cluster SOC standard data set The cluster SOC, is the cluster maximum SOC of the cluster SOC standard data set.

8. The method according to claim 3, characterized in that The first adjustment coefficient is related to the temperature, internal resistance, aging degree, charging rate and expected discharge depth of the energy storage system.

9. The method according to claim 4, characterized in that The second adjustment coefficient is related to the temperature, internal resistance, aging degree, charging rate and expected discharge depth of the battery cluster of the energy storage system.

10. A battery cluster SOC balancing control device for an energy storage system, characterized in that: include: A data acquisition module, used to acquire the cluster SOC of multiple battery clusters of the energy storage system and the single cell SOC of multiple battery cells in each battery cluster, and obtain a cluster SOC data set consisting of multiple cluster SOCs and multiple single cell SOC data sets consisting of single cell SOCs containing multiple battery cells; A data calculation module, used for obtaining a system average SOC of the energy storage system and a plurality of average SOCs of cells of a plurality of battery clusters according to the cluster SOC data set and the plurality of cell SOC data sets; A first judgment module, configured to judge whether an absolute difference between the cluster SOC in the cluster SOC data set and the system average SOC is greater than a first SOC threshold; a data processing module, configured to, in response to an absolute difference between the cluster SOC in the cluster SOC data set and the system average SOC being greater than a first SOC threshold, record the battery cluster that meets the condition as a target battery cluster, and all target battery clusters constitute a target battery cluster set; A second judgment module, used to judge whether the absolute difference between the average value of the maximum SOC and the minimum SOC of the cells of the target battery cluster in the target battery cluster set and the average SOC of the cells is greater than a second SOC threshold; A first balancing module, configured to perform SOC balancing inside the target battery cluster using a first balancing control strategy in response to an absolute difference between an average value of a maximum SOC and a minimum SOC of a single cell of a target battery cluster in the target battery cluster set and a single cell average SOC being greater than a second SOC threshold; A data updating module, used for updating the cluster SOC data set and determining whether the cluster SOCs in the cluster SOC data set are consistent; The second balancing module is configured to, in response to inconsistency in the cluster SOCs in the cluster SOC data set, adopt a second balancing control strategy to balance the SOCs between the battery clusters of the energy storage system.

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