A method of equalization control and related apparatus

Abstract

The application provides a balancing control method and related device, and relates to the field of energy storage. After the charging and discharging operation of the energy storage system is completed, the state of charge of each battery cell is determined, the target battery cell is determined based on the charging and discharging state of the battery cluster, and the initial balancing amount and the target balancing amount of the target battery cell are obtained based on the state of charge of the target battery cell. If the state of charge of at least one battery cell is in a nonlinear region and the state of charge of at least one battery cell is in a linear region, for the target battery cell satisfying the fuzzy calculation condition, one of the initial balancing amount and the target balancing amount of the target battery cell is determined by the endpoint value of the nonlinear region. When the initial balancing amount or the target balancing amount of the battery cell cannot be accurately determined, resulting in that the balancing amount cannot be accurately determined, one of the initial balancing amount and the target balancing amount is determined by the endpoint value of the nonlinear region, and then the accurate balancing amount of the target battery cell is obtained by using the initial balancing amount and the target balancing amount of the target battery cell.

Description

Technical Field

[0001] This application relates to the field of energy storage, and more specifically, to a method for equalization control and related devices. Background Technology

[0002] Configuring an energy storage system can improve the reliability of energy utilization. When energy production is sufficient, the energy storage system stores energy, and when energy production is insufficient, the energy storage system releases energy.

[0003] Energy storage systems consist of battery clusters, which in turn contain multiple cells. If there are significant differences in the State of Charge (SOC) among different cells within the same battery cluster, the maximum usable capacity of the entire energy storage system will decrease. Therefore, SOC balancing methods can be used to reduce the SOC differences between cells. However, accurately determining the SOC balancing amount for each cell is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] In view of this, this application provides a balancing control method and related apparatus to solve the problem of inaccurate SOC balancing of battery cells.

[0005] To solve the above-mentioned technical problems, this application adopts the following technical solution:

[0006] Firstly, this application discloses an equilibrium control method, including:

[0007] After the energy storage system's charging and discharging operations are completed, the open-circuit voltage of each cell in the battery cluster is obtained to determine the state of charge corresponding to each cell.

[0008] The target cell is determined based on the charge and discharge state of the battery cluster;

[0009] Based on the state of charge of the target cell, the initial equalization amount and the target equalization amount of the target cell are obtained; wherein, in the case that at least one cell's state of charge is in a nonlinear region and at least one cell's state of charge is in a linear region, for the target cell that satisfies the fuzzy calculation conditions, one of the values ​​of the initial equalization amount and the target equalization amount is determined by the endpoint value of the nonlinear region; the nonlinear region is the nonlinear region in the open-circuit voltage curve.

[0010] The equalization amount of the target battery cell is obtained by using the initial equalization amount and the target equalization amount of the target battery cell.

[0011] Optionally, determining the target cell based on the charge / discharge state of the battery cluster includes:

[0012] When the battery cluster is in a discharge state, at least one of the battery cells is selected as the target battery cell.

[0013] Optionally, when the charge / discharge state of the battery cluster is discharging, obtaining the initial balancing amount and target balancing amount of the target battery cell based on the state of charge of the target battery cell includes:

[0014] When the state of charge corresponding to the target cell is in the nonlinear region, the minimum endpoint value in the nonlinear region is taken as the initial balancing amount of the target cell, and the lowest state of charge among all cells in the linear region is taken as the target balancing amount of the target cell.

[0015] Optionally, determining the target cell based on the charge / discharge state of the battery cluster includes:

[0016] When the charge / discharge state of the battery cluster is charging, at least one of the cells whose state of charge is in the linear region is selected as the target cell.

[0017] Optionally, when the charge / discharge state of the battery cluster is charging, obtaining the initial balancing amount and target balancing amount of the target battery cell based on the state of charge of the target battery cell includes:

[0018] When the state of charge of all cells is unevenly distributed in the linear region, the state of charge of the target cell is used as the initial balancing quantity of the target cell, and the maximum endpoint value in the nonlinear region is used as the target balancing quantity of the target cell.

[0019] Optionally, obtaining the balancing amount of the target battery cell using the initial balancing amount and the target balancing amount includes:

[0020] The difference between the initial balancing amount and the target balancing amount of the target battery cell is taken as the balancing amount of the target battery cell.

[0021] Optionally, after obtaining the equalization amount of the target battery cell, the method further includes:

[0022] Perform a state-of-charge balancing operation between battery cells based on the balancing amount of the target battery cell;

[0023] Specifically, when the state of charge of the target cell is greater than the target equalization amount, the target cell is controlled to discharge until the state of charge of the target cell equals the target equalization amount.

[0024] Optionally, the linear region is the region in the open-circuit voltage curve where the open-circuit voltage of the battery cell is proportional to its state of charge.

[0025] Optionally, the end of the energy storage system's charging and discharging operation includes: the energy storage system stopping the charging and discharging operation and the battery cells being left to stand for a specified time.

[0026] Secondly, this application discloses an equalization control device, comprising:

[0027] The acquisition module is used to acquire the open-circuit voltage of each cell in the battery cluster after the energy storage system charging and discharging operation is completed, so as to determine the state of charge corresponding to each cell.

[0028] The determination module is also used to determine the target cell based on the charge and discharge state of the battery cluster;

[0029] The acquisition module is further configured to acquire the initial balancing amount and the target balancing amount of the target battery cell based on the state of charge of the target battery cell; wherein, in the case where the state of charge of at least one battery cell is in a nonlinear region and the state of charge of at least one battery cell is in a linear region, for the target battery cell that satisfies the fuzzy calculation conditions, one of the values ​​of the initial balancing amount and the target balancing amount is determined by the endpoint value of the nonlinear region; the nonlinear region is the nonlinear region in the open-circuit voltage curve;

[0030] The determining module is further configured to obtain the equalization amount of the target battery cell using the initial equalization amount and the target equalization amount of the target battery cell.

[0031] Thirdly, this application discloses a controller for performing the above-described equalization control method.

[0032] Fourthly, this application discloses an equalization control system, including a battery cluster and the aforementioned controller.

[0033] Fifthly, this application discloses a computer program product including computer-readable instructions, which, when executed on an electronic device, cause the electronic device to implement the above-described equalization control method provided in the embodiments of this application.

[0034] This application provides a balancing control method and related apparatus. In this application, after the energy storage system's charging and discharging operation is completed, the open-circuit voltage of each cell in the battery cluster is acquired to determine the state of charge (SOC) corresponding to each cell. Based on the SOC of the battery cluster, a target cell is determined. Based on the SOC of the target cell, the initial balancing amount and the target balancing amount of the target cell are obtained. Specifically, when at least one cell's SOC is in a non-linear region and at least one cell's SOC is in a linear region, for the target cell that satisfies the fuzzy calculation conditions, one of the initial balancing amount and the target balancing amount is determined through the endpoint value of the non-linear region. This allows for accurate determination of the balancing amount when the initial balancing amount or the target balancing amount of the cell cannot be accurately determined. By using the endpoint value of the non-linear region, a more accurate balancing amount of the target cell can be obtained using the initial balancing amount and the target balancing amount. This enables SOC balancing operations to be performed based on the balancing amount, reducing the SOC difference between cells. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0036] Figure 1 A flowchart of an equalization control method provided in an embodiment of this application;

[0037] Figure 2 A schematic diagram of an OCV curve provided for an embodiment of this application;

[0038] Figure 3 A schematic diagram illustrating a scenario for a post-discharge equalization control method provided in an embodiment of this application;

[0039] Figure 4 A schematic diagram illustrating a scenario of a post-charging equalization control method provided in an embodiment of this application;

[0040] Figure 5 This is a schematic diagram of the structure of an equalization control device provided in an embodiment of this application. Detailed Implementation

[0041] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0042] Configuring an energy storage system can improve the reliability of energy utilization. When energy production is sufficient, the energy storage system stores energy, and when energy production is insufficient, the energy storage system releases energy.

[0043] Energy storage systems consist of battery clusters, which in turn contain multiple cells. Due to variations in cell consistency, temperature differences at different locations within the container, differences in cell SOH (State of Health), and variations in capacity and internal resistance between different batches of cells, there are differences in SOC among different cells within the same battery cluster. Some cells have a higher SOC, while others have a lower SOC. The maximum usable capacity of the entire energy storage system is affected by the lowest SOC. The differences between different SOCs reduce the maximum usable capacity of the entire energy storage system, limiting the energy available to the outside world and making it unable to meet actual energy supply demands.

[0044] In this embodiment of the application, the problem of reduced maximum available power of the energy storage system due to inconsistent SOC of the cells can be solved by cell SOC balancing. Through SOC balancing operation, cells with unbalanced SOC can be balanced in a timely manner, reducing the SOC difference between different cells, thereby reducing the impact of the lowest SOC on the maximum available power of the energy storage system, increasing the maximum available power of the energy storage system, and meeting the actual energy supply demand.

[0045] When performing cell SOC balancing, it is necessary to accurately determine the SOC balancing amount of each cell. Therefore, in this embodiment, after the energy storage system's charging and discharging operation is completed, the open-circuit voltage of each cell in the battery cluster is obtained to determine the state of charge (SOC) corresponding to each cell. Based on the SOC of the battery cluster, a target cell is determined. Based on the SOC of the target cell, the initial balancing amount and the target balancing amount of the target cell are obtained. Where at least one cell's SOC is in a non-linear region and at least one cell's SOC is in a linear region, for a target cell that meets the fuzzy calculation conditions, one of the initial balancing amount and the target balancing amount is determined through the endpoint value of the non-linear region. This allows for accurate determination of the balancing amount when the initial balancing amount or the target balancing amount cannot be accurately determined. By using the endpoint value of the non-linear region, a more accurate balancing amount of the target cell can be obtained using the initial balancing amount and the target balancing amount, thus enabling SOC balancing operations based on the balancing amount and reducing SOC differences between cells.

[0046] Based on the above, one embodiment of this application provides a balanced control method, the execution subject of which can be a controller such as a cell controller or an energy storage system controller.

[0047] Reference Figure 1 An equalization control method may include:

[0048] S11. After the energy storage system charging and discharging operation is completed, obtain the open-circuit voltage of each cell in the battery cluster to determine the state of charge corresponding to each cell.

[0049] In real-world scenarios, energy storage systems consist of battery clusters, which in turn consist of multiple battery cells. The type of battery cell can be determined based on the actual configuration, such as lithium iron phosphate cells.

[0050] Energy storage systems can perform charging and discharging operations according to actual needs. Taking the photovoltaic field as an example, if the photovoltaic system generates a large amount of electricity, the excess electricity can be stored in the energy storage system. When the photovoltaic system generates less electricity and cannot meet the electricity demand, the electricity stored in the energy storage system can be released to provide sufficient electricity. This process involves the charging and discharging operations of the energy storage system.

[0051] During the charging and discharging process, the electrode potential of a battery cell may deviate from its equilibrium potential, a phenomenon known as polarization. To avoid inaccurate State of Charge (SOC) values ​​within the cell caused by polarization, one implementation method involves the energy storage system ceasing charging and discharging operations and allowing the battery cell to rest for a specified time after the charging and discharging operation ends. Specifically, after the energy storage system stops charging and discharging, the battery cell is left to rest for a specified time (the specific time can be configured according to actual needs) to allow depolarization (depolarization refers to the process of reducing or eliminating polarization to return the electrode potential to its equilibrium potential) to complete. Once the voltage reaches the depolarization voltage, the battery cell voltage returns to its equilibrium potential, allowing for SOC balancing.

[0052] After cell depolarization, when performing cell SOC balancing, it is first necessary to determine the actual SOC value of the cell.

[0053] like Figure 2 As shown, Figure 2 This is the OCV (Open Circuit Voltage) - SOC (State of Charge) curve of the battery cell in the embodiments of this application. Figure 2 In the graph, the horizontal axis represents the State of Charge (SOC) of the battery cell, and the vertical axis represents the Open Voltage Capacity (OCV) of the battery cell. The vertical axis is marked with voltages V0, V1, V2, and V3. V0 is the initial voltage value, V1 corresponds to SOC1, V2 to SOC2, and V3 to SOC3. This can be seen from... Figure 2 As can be seen, the OCV-SOC curve can be divided into three parts: SOC0~SOC1, SOC1~SOC2, and SOC2~SOC3. SOC0~SOC1 represents the linear range of OCV at the end of the discharge of the lithium iron phosphate cell (i.e., the period of lower SOC), which is the low SOC linear region in this embodiment. SOC1~SOC2 represents the plateau period of the lithium iron phosphate cell voltage, which is the nonlinear region in this embodiment. SOC2~SOC3 represents the linear range at the end of the charging of the lithium iron phosphate cell (i.e., the period of higher SOC), which is the high SOC linear region in this embodiment.

[0054] From Figure 2The distribution across different voltage ranges shows that when the cell voltage is between V0 and V1, the State of Charge (SOC) falls within the SOC0~SOC1 range. Within this range, voltage and SOC are directly proportional, allowing for accurate SOC calculation based on the voltage value. Similarly, when the cell voltage is between V2 and V3, the SOC falls within the SOC2~SOC3 range. Again, voltage and SOC are directly proportional within this range, enabling accurate SOC calculation based on the voltage value. Therefore, it can be concluded that there is a linear relationship between the static OCV voltage and SOC of the lithium iron phosphate cell within the SOC0~SOC1 and SOC2~SOC3 ranges. Thus, the accurate cell SOC can be calculated using the OCV voltage, and then SOC balancing can be performed using the actual SOC value of the cell.

[0055] In SOC1~SOC2, there is a non-linear relationship between the static OCV voltage and SOC, so the cell SOC cannot be accurately calculated from the OCV voltage; only an approximate estimate of the cell SOC can be obtained.

[0056] In practice, voltage sensors and other devices can be used to detect the open-circuit voltage of each cell in the battery cluster. To improve the accuracy of the collected voltage values, interference can be filtered out through filtering and other operations. Then, based on... Figure 2 The curves shown determine the SOC of each cell. In one embodiment, if the open-circuit voltage is within the voltage range corresponding to the low SOC linear region (i.e., the SOC0~SOC1 interval) and the high SOC linear region (i.e., the SOC2~SOC3 interval), the cell SOC can be accurately determined; if the open-circuit voltage is within the voltage range corresponding to the plateau period interval, the cell SOC can be roughly determined.

[0057] S12. Based on the charge and discharge state of the battery cluster, determine the target cell.

[0058] In this embodiment, the charging and discharging states of the battery cluster are divided into two cases: discharging and charging. The target cell refers to a cell that has an balancing quantity and requires balancing operation. The process of determining the target cell differs between the discharging and charging cases.

[0059] S13. Based on the state of charge of the target battery cell, obtain the initial balancing amount and the target balancing amount of the target battery cell.

[0060] The initial equalization value of the target cell refers to a state of charge value used during the equalization operation. This state of charge value can be the actual state of charge of the target cell or the fuzzy state of charge of the target cell. Which state of charge is used depends on the region where the states of charge of all cells are located.

[0061] In one implementation, the areas where all the battery cells are located can be divided into four cases.

[0062] The first scenario: all cells are in the low SOC linear region, which is the SOC0~SOC1 range mentioned above.

[0063] The second scenario: some cells are in the low SOC linear region, and some cells are in the non-linear region. The non-linear region is the aforementioned SOC1~SOC2.

[0064] The third scenario: some cells are in the nonlinear region and some cells are in the high SOC linear region. This high SOC linear region is the SOC2~SOC3 interval mentioned above.

[0065] The fourth scenario: All cells are in the high SOC linear region.

[0066] For the above four situations, an appropriate method can be used to determine the initial equalization amount of the target battery cell.

[0067] The target balance quantity for a target cell refers to a state of charge (SOC) value that is ultimately achieved through balancing operations. This SOC value can be the actual SOC of a cell or a fuzzy SOC. The specific SOC value used depends on the region where the SOCs of all cells are located. The region where the SOCs of all cells are located can be determined by referring to the four scenarios mentioned above.

[0068] In one implementation, when at least one cell's state of charge (SOC) is in a nonlinear region and at least one cell's SOC is in a linear region (the linear region being the region in the open-circuit voltage curve where the cell's open-circuit voltage is proportional to its SOC, specifically the low SOC linear region or the high SOC linear region), for a target cell that satisfies the fuzzy calculation conditions, one of the initial equalization quantity and the target equalization quantity is determined by the endpoint value of the nonlinear region; the nonlinear region is the nonlinear region in the open-circuit voltage curve, specifically the aforementioned plateau period interval.

[0069] Specifically, the target battery cell that satisfies the fuzzy calculation conditions can be:

[0070] Cells that are in the nonlinear region when the battery cluster is discharging, or cells that are in the linear region when the battery cluster is charging.

[0071] In this embodiment, during equalization operation, the high SOC cell discharges, so that the voltage of the high SOC cell after discharge is the same as or similar to that of the low SOC cell.

[0072] In the battery cluster discharge scenario, the target cell at the end of the discharge period has a low SOC. The SOC of the target cell is generally in the low SOC linear region or non-linear region. The state of charge of the cell in the low SOC linear region can be accurately obtained through the open circuit voltage, while the state of charge of the cell in the non-linear region cannot be accurately obtained through the open circuit voltage.

[0073] In general, during battery cluster discharge scenarios, by Figure 2 It is known that the SOC of a target cell in the nonlinear region is higher than that of a target cell in the low-SOC linear region. Therefore, it is necessary to perform discharge operations on both the target cells in the nonlinear region and the high-SOC target cells in the linear region to achieve SOC equalization and voltage uniformity. When performing discharge operations on the target cells in the nonlinear region, since their actual SOC cannot be accurately determined, i.e., their initial equalization amount cannot be accurately determined, the initial equalization amount can be determined by the endpoint values ​​of the nonlinear region.

[0074] In addition, in battery cluster charging scenarios, the state of charge (SOC) of cells in the late stage of charging is relatively high. Cells are generally in the high SOC linear region or non-linear region. The state of charge of cells in the high SOC linear region can be accurately obtained through open circuit voltage, while the state of charge of cells in the non-linear region cannot be accurately obtained through open circuit voltage.

[0075] In general, in battery cluster charging scenarios, by Figure 2 It is known that the State of Charge (SOC) of a battery cell in the nonlinear region is lower than that of a cell in the high SOC linear region. Therefore, it is necessary to use the cell in the high SOC linear region as the target cell for discharge to achieve SOC equalization and voltage uniformity. When discharging the target cell in the high SOC linear region, its actual SOC can be accurately determined, but the SOC of the cell in the nonlinear region cannot be accurately determined, making it impossible to accurately determine the equalization target quantity. In this case, the equalization target quantity can be determined by the endpoint value of the nonlinear region.

[0076] S14. Using the initial balancing amount and the target balancing amount of the target cell, obtain the balancing amount of the target cell.

[0077] Here, "balancing amount" refers to the State of Charge (SOC) balancing amount, which is the amount of SOC that needs to be transferred during the charge transfer process. For example, if the SOC balancing amount is 10%, then SOC transfer can be performed at a rate of 10%.

[0078] After obtaining the initial balancing amount and the target balancing amount of the target cell, the balancing amount of the target cell can be obtained using these two data.

[0079] In this embodiment, after the energy storage system's charging and discharging operations are completed, the open-circuit voltage of each cell in the battery cluster is acquired to determine the state of charge (SOC) corresponding to each cell. Based on the SOC of the battery cluster, a target cell is determined. Based on the SOC of the target cell, the initial equilibrium value and the target equilibrium value of the target cell are obtained. Where at least one cell's SOC is in a non-linear region and at least one cell's SOC is in a linear region, for a target cell that satisfies the fuzzy calculation conditions, one of the initial equilibrium value and the target equilibrium value is determined through the endpoint value of the non-linear region. This allows for accurate determination of the equilibrium value when the initial equilibrium value or the target equilibrium value of the cell cannot be accurately determined. By using the endpoint value of the non-linear region, a more accurate equilibrium value of the target cell can be obtained using the initial equilibrium value and the target equilibrium value. This enables SOC balancing operations to be performed based on the equilibrium value, reducing SOC differences between cells.

[0080] Based on any of the above embodiments, determining the target cell based on the charge / discharge state of the battery cluster includes:

[0081] When the battery cluster is in a discharge state, at least one of the battery cells is selected as the target battery cell.

[0082] In this embodiment, during the battery cluster discharge scenario, since the cells need to undergo discharge operations, the state of charge (SOC) of the cells will not be large. Therefore, the target cell is generally located in a low SOC linear region or a non-linear region. The state of charge of the target cell in the low SOC linear region can be accurately obtained through open-circuit voltage, while the state of charge of the target cell in the non-linear region cannot be accurately obtained through open-circuit voltage.

[0083] If the target cell's state of charge (SOC) is in the low SOC linear region, then the cell's actual SOC can be used directly for balancing. In this case, at least one cell in the low SOC linear region can be used as the target cell. In one implementation, each cell in the linear region can be used as the target cell.

[0084] When the state of charge of the target cell is in the nonlinear region, for cells in the nonlinear region, such as... Figure 2 As shown, when the cell voltage is in the range of V1 and V2, the SOC is in the range of SOC1 to SOC2. At this time, the cell's SOC is in the nonlinear region. In this nonlinear region, the voltage and SOC have a nonlinear relationship, and the cell's SOC cannot be calculated from the voltage. That is, the actual SOC value of the cell cannot be accurately calculated at this time.

[0085] If the actual SOC value of the battery cell is not accurately calculated, one implementation method abandons the actual SOC value for cell balancing and instead uses a fuzzy SOC value to calculate the balancing amount. This fuzzy SOC value is obtained through fuzzy calculation; if it represents the minimum endpoint value of the non-linear region, it ensures that cells in the non-linear region can be balanced at least by an amount equal to "SOC1 - minimum SOC value". This is understandable, since the SOC of a cell in the non-linear region is definitely greater than SOC1, using SOC1 to calculate the balancing amount ensures that the balancing amount will not exceed the maximum balancing amount achievable with the cell's accurate SOC, thus preventing over-balancing. Compared to not performing SOC balancing, this balancing operation reduces the SOC difference between cells.

[0086] In this embodiment, at least one cell in the nonlinear state of charge region can be used as the target cell. In one implementation, each cell in the nonlinear state of charge region is used as the target cell. In this case, if each cell in the linear region is used as the target cell, then in the battery cluster discharge state, the target cell includes both each cell in the nonlinear region and each cell in the linear region, that is, the target cell includes every cell in the entire battery cluster.

[0087] In addition, only a portion of all cells can be selected as target cells, such as each cell whose state of charge is in the nonlinear region. Alternatively, some cells in the nonlinear region can be selected as target cells, such as cells with a larger state of charge (SOC) among those cells. The specific method used can be determined based on the actual configuration.

[0088] In this embodiment, at least one of the battery cells is used as the target battery cell, and a discharge operation is performed on it to achieve SOC balance among the battery cells.

[0089] In one implementation, based on any embodiment where the charge / discharge state of the battery cluster is in discharge mode, the initial balancing amount and the target balancing amount of the target battery cell are obtained based on the state of charge of the target battery cell, including:

[0090] When the state of charge corresponding to the target cell is in the nonlinear region, the minimum endpoint value in the nonlinear region is taken as the initial balancing amount of the target cell, and the lowest state of charge among all cells in the linear region is taken as the target balancing amount of the target cell.

[0091] Specifically, since the SOC value of a battery cell can only be accurately determined when it is in the low SOC linear region, this embodiment requires ensuring that at least one battery cell operates in the low SOC linear region. Only under this condition can at least one battery cell have an accurate SOC value, and only then can the SOC balancing benchmark be determined for SOC balancing operations. If all battery cells are in the nonlinear region, the SOC value of each battery cell cannot be accurately calculated, and therefore, SOC balancing operations are not performed.

[0092] In practical scenarios, when the state of charge (SOC) of the target cell is in the linear region, the actual SOC of the target cell is directly used for balancing, and the SOC of all target cells moves towards the lowest SOC. Therefore, for a target cell in the linear region, the current SOC of the target cell is used as the initial balancing value, and the lowest SOC among all cells in the linear region is used as the target balancing value.

[0093] When the battery cluster discharges, if the state of charge (SOC) of the target cell is in a nonlinear region, the SOC value of the cell within this nonlinear region cannot be accurately calculated. Therefore, fuzzy calculation can be performed on this SOC value. During fuzzy calculation, the minimum endpoint value in the nonlinear region, i.e., the value of SOC1, is a definite value within the SOC1~SOC2 range. SOC1 is used as the fuzzy SOC value of the target cell whose SOC is within the SOC1~SOC2 range. This fuzzy SOC value is the initial equalization value, and equalization operations are performed according to this initial equalization value.

[0094] During the balancing operation, it is necessary for the cell with a larger SOC to discharge to the cell with a smaller SOC or for the cell with a larger SOC to discharge directly. When there is at least one cell in the linear state of charge region, since the lowest SOC needs to be used as the balancing benchmark, it is necessary to determine the cell with the smallest SOC that can be accurately calculated.

[0095] In this embodiment of the application, the cells located in the low SOC linear region are first identified. Based on the SOC value of the cells in the low SOC linear region, the cells corresponding to the lowest SOC value are selected. The state of charge of the cells is the lowest state of charge, which is the target amount for the balance of the target cells.

[0096] In this embodiment, under the battery cluster discharge scenario, the SOC of the cells in the nonlinear region is equalized using a fuzzy SOC value. This avoids the problem of inaccurate SOC equalization caused by the inability to accurately determine the actual SOC value of the cells in the nonlinear region. Furthermore, after each charge and discharge cycle of the energy storage system, the minimum imbalance amount of the system ("SOC1 - minimum SOC value") is calculated in a timely manner through a fuzzy calculation method, and the equalization function is immediately activated, thereby enabling the inconsistency problem between cells to be resolved in a timely manner.

[0097] In one implementation of this application, when the battery cluster is in a discharging state, after obtaining the initial balancing amount and the target balancing amount of the target battery cell, the balancing amount of the target battery cell is obtained using the initial balancing amount and the target balancing amount, including:

[0098] The difference between the initial balancing amount and the target balancing amount of the target battery cell is taken as the balancing amount of the target battery cell.

[0099] Specifically, within the same battery cluster, since the balancing target is the minimum SOC, the SOC value of the target cell is greater than the minimum SOC. During the balancing process, the SOC value of the target cell can be reduced by controlling the target cell to charge the cell with the lower SOC (i.e., charging the cell with the lower SOC and discharging the cell with the higher SOC), or by controlling the target cell to directly discharge. In this embodiment, the difference between the initial balancing amount and the balancing target amount of the target cell is taken as the balancing amount of the target cell, i.e., the balancing amount of the target cell = initial balancing amount - balancing target amount.

[0100] In this embodiment, when the battery cell is in the discharge state, the actual SOC is used as the initial equalization value for cells in the low SOC linear region. Then, the difference between the actual SOC value and the lowest SOC value is calculated as the equalization value for the cell. This ensures that the cells in the low SOC linear region are equalized according to their actual state of charge, reducing the SOC difference between cells. For cells in the nonlinear region, SOC1 is used as the initial equalization value. Then, the difference between SOC1 and the lowest SOC value is calculated as the equalization value for the cell. This ensures that the cells in the nonlinear region can at least be equalized according to SOC1 by the equalization value of "SOC1 - lowest SOC value". Compared to not performing SOC equalization, this reduces the SOC difference between cells.

[0101] Based on any embodiment where the charge / discharge state of the aforementioned battery cluster is in the discharge state, after obtaining the equalization amount of the target battery cell, the method further includes:

[0102] Perform a state-of-charge balancing operation between battery cells based on the balancing amount of the target battery cell;

[0103] Specifically, if the state of charge of the target cell is greater than the target equalization amount, the target cell is controlled to discharge until the state of charge of the target cell equals the target equalization amount.

[0104] In this embodiment, the SOC imbalance between cells refers to a significant difference in SOC between cells, with some cells having a higher SOC value and others a lower SOC value. Therefore, after obtaining the SOC balance value of the cells, a SOC balancing operation is required. After the SOC balancing operation, if the target cell's state of charge is still not at the balanced target value, the target cell can be controlled to discharge. Of course, if other cells have an SOC greater than the balanced target value, these other cells can also be controlled to discharge, so that the state of charge among the cells is balanced.

[0105] In one implementation, cells with high SOC have more charge and cells with low SOC have less charge. To ensure SOC balance among the cells, cells with higher SOC can discharge to cells with lower SOC. Specifically, cells with SOC greater than or less than the target balance amount can be controlled to discharge to cells with the target balance amount. This allows cells with lower SOC to absorb charge and increase their own SOC, while cells with higher SOC decrease their SOC value after discharge, thus bringing the SOC values ​​of the cells closer together.

[0106] It should be noted that when power is transferred between cells, since multiple cells are charging the same cell with the lowest SOC, the cell with the lowest SOC receives power from multiple cells with higher SOC. At this time, the amount of SOC transferred from each high SOC cell to the cell with the lowest SOC should be less than the SOC equalization amount of the high SOC cells to avoid the cell receiving power having too high a charge. Subsequently, for cells with non-lowest SOC, the portion of the discharge that is less than the cell's SOC equalization amount is directly released into the air.

[0107] In another implementation, during SOC balancing, cells with a larger SOC (i.e., SOC greater than or not equal to the balancing target) can be directly discharged. This electrical energy is converted into heat energy and released into the atmosphere. Cells with the lowest SOC (SOC equal to the balancing target) are not adjusted. Ultimately, this makes the SOC of all cells close, reducing the impact of the lowest SOC value on the maximum available power of the entire energy storage system, thereby increasing the maximum available power of the entire energy storage system.

[0108] In this embodiment, SOC balancing is achieved among the battery cells to reduce SOC differences. This reduces the impact of the lowest SOC on the maximum available capacity of the energy storage system, thereby increasing the maximum available capacity and meeting actual energy supply demands.

[0109] The above embodiments describe the determination process of the target cell, the initial balancing amount of the target cell, and the target balancing amount in a battery cluster discharge scenario, as well as the corresponding balancing process. Another implementation of this application provides the determination process of the target cell, the initial balancing amount of the target cell, and the target balancing amount in a battery cluster charging scenario, as well as the corresponding balancing process. In one implementation, determining the target cell based on the charging and discharging state of the battery cluster includes:

[0110] When the charge / discharge state of the battery cluster is charging, at least one of the cells whose state of charge is in the linear region is selected as the target cell.

[0111] In a specific implementation, in the battery cluster charging scenario, as the battery cells need to be charged, the SOC of the battery cells is generally large. Therefore, the range in which the battery cells are located is generally a non-linear region or a high SOC linear region.

[0112] Since the SOC value of a battery cell can only be accurately determined based on its voltage when the cell is in the high SOC linear region, this embodiment requires that at least one cell's operating range be within the high SOC linear region. Only under this condition can at least one cell have an accurate SOC value for SOC balancing. If all cells are in the non-linear region, the SOC value of each cell cannot be accurately calculated, and SOC balancing is not performed in this case.

[0113] The state of charge (SOC) of a battery cell in the high SOC linear region can be accurately obtained using open-circuit voltage, while the SOC of a battery cell in the nonlinear region cannot be accurately obtained using open-circuit voltage. Furthermore, the SOC of a battery cell in the high SOC linear region is greater than that of a battery cell in the nonlinear region. Therefore, it is necessary to discharge the battery cells in the high SOC linear region so that their SOC after discharge is close to that of the battery cells in the nonlinear region, thus achieving SOC equalization. Therefore, in this application, at least one battery cell in the high SOC linear region is used as the target battery cell, and the target battery cell is discharged to achieve SOC equalization.

[0114] In some implementations, each of the cells in the high SOC linear region can be used as the target cell, or one or more cells in the high SOC linear region can be used as the target cell, such as selecting the cell with a larger SOC value as the target cell. The specific method used to determine the target cell can be based on the actual configuration.

[0115] In this embodiment, at least one of the battery cells in the linear state of charge region is selected as the target battery cell, and a discharge operation is performed on it to achieve SOC balance among the battery cells.

[0116] Based on any embodiment where the charge / discharge state of the battery cluster is charging, in one implementation of this application, when the charge / discharge state of the battery cluster is charging, the initial balancing amount and the target balancing amount of the target battery cell are obtained based on the state of charge of the target battery cell, including:

[0117] When the state of charge of all cells is unevenly distributed in the linear region, the state of charge of the target cell is used as the initial balancing quantity of the target cell, and the maximum endpoint value in the nonlinear region is used as the target balancing quantity of the target cell.

[0118] It is understandable that the state of charge of all battery cells is not uniformly in the linear region, meaning that some battery cells are in the linear region (such as the high SOC linear region), while some battery cells are in the nonlinear region.

[0119] Specifically, in the battery cluster charging scenario, the state of charge (SOC) of all cells can be divided into two cases: one is that the SOC of all cells is in the high SOC linear region, and the other is that the SOC of some cells is in the non-linear region, while the SOC of some cells is in the high SOC linear region.

[0120] For cases where all cells are in the high SOC linear region, balancing can be performed directly using the actual SOC of the cells. This discharges the high SOC cells to the lowest SOC within the high SOC linear region, thus achieving SOC balancing. Specifically, when all cells are in the linear region, the SOC of each target cell is used as the initial balancing value for that target cell, and the lowest SOC among all cells in the high SOC linear region is used as the target balancing value for each target cell.

[0121] For cases where some battery cells have a state of charge (SOC) in the nonlinear region and others in the high SOC linear region, it is necessary to discharge the cells in the high SOC linear region to make their post-discharge SOC close to that of the cells in the nonlinear region. Therefore, the SOC of the target battery cell can be directly used as the initial balancing quantity for the target battery cell. Since the SOC of the cells in the nonlinear region cannot be accurately determined, a fuzzy SOC calculation can be performed on the balancing target quantity of the target battery cell. Because the SOC is generally large during charging, the value of SOC2 is a definite value in the SOC1~SOC2 range. Therefore, SOC2 can be used as the balancing target quantity for the target battery cell in the high SOC linear region.

[0122] In this embodiment, when the battery cluster is charging, the cells in the high SOC linear region use SOC2 as their own balancing target amount, so that subsequent SOC balancing operations can be performed according to the initial balancing amount and the balancing target amount of the target cells.

[0123] Based on the above embodiments, in one implementation of this application, when the battery cluster is in a charging state, the balancing amount of the target battery cell is obtained using the initial balancing amount and the target balancing amount of the target battery cell, including:

[0124] The difference between the initial balancing amount and the target balancing amount of the target battery cell is taken as the balancing amount of the target battery cell.

[0125] In this embodiment, similar to the battery cluster charging scenario described above, the difference between the initial balancing amount and the target balancing amount of the target battery cell is used as the balancing amount of the target battery cell, so that the SOC of the target battery cell is balanced according to the balancing "initial balancing amount - target balancing amount".

[0126] If all target cells are in the high SOC linear region, then "initial balancing amount - target balancing amount" is the difference between the actual state of charge of the target cells and the lowest state of charge in the high SOC linear region. In other words, all target cells are balanced according to their actual state of charge to achieve SOC balance and voltage uniformity.

[0127] If some target cells are in the high SOC linear region and some are in the non-linear region, since the state of charge of cells in the non-linear region cannot be accurately determined, no balancing operation is performed on the cells in the non-linear region. For target cells in the high SOC linear region, the difference between "actual SOC value - SOC2" is calculated. This difference is the balancing amount for the cell, ensuring that the cells in the high SOC linear region are balanced by at least "actual SOC value - SOC2" of charge. Compared to not performing SOC balancing operation, this reduces the SOC difference between cells.

[0128] In this embodiment, since the SOC of a cell in the nonlinear region is definitely less than SOC2, using SOC2 as the balancing target value, compared to using the inaccurate SOC of a cell in the nonlinear region as the balancing target value, can prevent the target cell from being over-balanced. Balancing operations based on this balancing value, compared to not performing SOC balancing operations, reduce the SOC difference between cells.

[0129] Based on any embodiment where the charge / discharge state of the battery cluster described above is charging, after obtaining the equalization amount of the target battery cell, the method further includes:

[0130] Perform a state-of-charge balancing operation between battery cells based on the balancing amount of the target battery cell;

[0131] Specifically, when the state of charge of the target cell is greater than the target equalization amount, the target cell is controlled to discharge until the state of charge of the target cell equals the target equalization amount.

[0132] In one implementation, when the target cell is discharging, the target cell in the high SOC linear region has more charge, while the cell in the non-linear region has less charge. To ensure SOC balance among the cells, the cell with the larger SOC can discharge to the cell with the smaller SOC, i.e., charging the low-SOC cell and discharging the high-SOC cell to reduce the SOC value of the target cell. Specifically, the serial number of the cell in the non-linear region can be obtained, and the target cell in the high SOC linear region can be controlled to discharge to the cell in the non-linear region with the smallest serial number, stopping when the SOC of the receiving cell reaches SOC2. Then, the target cell in the high SOC linear region can be controlled to discharge to the cell in the non-linear region with the second smallest serial number, stopping when the SOC of the receiving cell reaches SOC2, and so on, until the SOC of all target cells in the high SOC linear region reaches SOC2, at which point the discharge stops.

[0133] It should be noted that the discharge operation of a target cell in the high SOC linear region to a cell in the nonlinear region can be a many-to-one operation, that is, multiple target cells in the high SOC linear region discharge to a cell in the nonlinear region. Alternatively, it can be a one-to-one operation, that is, one target cell in the high SOC linear region discharges to a cell in the nonlinear region. The specific method used depends on the actual configuration.

[0134] Through the above balancing operation, cells with larger SOC and cells with smaller SOC are brought closer to SOC2, thereby making the SOC values ​​of the cells similar and achieving SOC balance and voltage uniformity among the cells.

[0135] In another implementation, during SOC balancing, cells with a larger SOC (i.e., SOC greater than or not equal to the balancing target) can be directly discharged. This electrical energy is converted into heat energy and released into the atmosphere. Non-target cells are not adjusted, ultimately bringing the SOC of all cells closer together. This reduces the impact of the lowest SOC value on the maximum available power of the entire energy storage system, thereby increasing the maximum available power of the entire energy storage system.

[0136] In this embodiment, SOC balancing is achieved between cells through SOC balancing operation, reducing the SOC difference between cells, thereby reducing the impact of the lowest SOC on the maximum available power of the energy storage system, increasing the maximum available power of the energy storage system, and meeting the actual energy supply demand.

[0137] In one implementation, refer to Figure 3 , Figure 3 The SOC equalization process after the discharge operation in this embodiment is as follows:

[0138] After the energy storage system finishes discharging and is left to stand for a period of time t0, wait for the cell depolarization to finish and the cell voltage to reach the depolarization voltage.

[0139] Ideally, all cell voltages are within the SOC0~SOC1 range. At this point, the SOC of each cell can be accurately obtained. Then, based on the OCV-SOC curve of the cell, the SOC value of the cell within the SOC0~SOC1 range can be obtained. The difference between the actual SOC value of each cell and the lowest SOC in the SOC0~SOC1 range is used as the SOC equalization value of each cell.

[0140] Generally, only some cells may fall within the SOC0~SOC1 range, while others fall within the SOC1~SOC2 range. In this case, only cells within the SOC0~SOC1 range can have an accurate SOC value. The SOC balancing value for cells within this range can be calculated using the method described above. Cells within the SOC1~SOC2 range cannot have an accurate SOC value because their voltage is at a plateau. Therefore, the difference between the SOC1 value and the lowest SOC value within the SOC0~SOC1 range is used as the SOC balancing value for cells within the SOC1~SOC2 range.

[0141] In extreme cases, if only one cell is located in the SOC0~SOC1 range, then for the cell located in the SOC1~SOC2 range, the difference between SOC1 and the SOC of the only cell located in the SOC0~SOC1 range is used as the SOC equalization value of the cell in the SOC1~SOC2 range.

[0142] Subsequently, SOC balancing is performed based on the SOC balancing amount calculated above. Specifically, high SOC cells charge low SOC cells or high SOC cells directly discharge, so that the SOC of the cells is similar.

[0143] It should be noted that if no cell is in the SOC0~SOC1 range, no balancing operation will be performed.

[0144] In another implementation, refer to Figure 4 , Figure 4The SOC balancing process in a charging scenario is presented, including the following steps:

[0145] After the energy storage system finishes charging and is left to stand still for a period of time t0, the cell depolarization is completed and the cell voltage reaches the depolarization voltage.

[0146] Ideally, all cell voltages are within the SOC2~SOC3 range. At this point, the SOC of each cell can be accurately obtained. Based on the OCV-SOC curve of the cell, the SOC value of the cell within the SOC2~SOC3 range can be obtained. The difference between the SOC value of other cells in this range and the lowest SOC value in this range is the SOC equalization amount of the cells within the SOC2~SOC3 range.

[0147] Generally, some battery cells fall within the SOC2~SOC3 range, while others fall within the SOC1~SOC2 range. The difference between the SOC value of the cells in the SOC2~SOC3 range and their SOC2 value is used as the SOC balancing factor for the cells in the SOC2~SOC3 range. In this case, the remaining cells are not balanced, or the cells in the SOC2~SOC3 range are used to charge the cells in the SOC1~SOC2 range to reduce the SOC difference between the cells.

[0148] Based on the SOC balancing amount calculated above, an SOC balancing operation is performed. Specifically, a high SOC cell charges a low SOC cell or a high SOC cell directly discharges, making the SOC of the cells similar.

[0149] If no cell is in the SOC2~SOC3 range, no balancing operation will be performed.

[0150] In this embodiment, for systems with poor cell consistency, since it is impossible to guarantee that all cells are in the linear range, this embodiment can determine the SOC fuzzy value of the cell (specifically, the aforementioned SOC1 or SOC2) when at least one cell is in the linear range, and then calculate the SOC balancing amount, thereby promptly initiating the cell balancing operation to ensure the SOC consistency of the entire cell system.

[0151] Based on the embodiments of the above-described equalization control method, another embodiment of this application provides an equalization control device, referring to... Figure 5 It can include:

[0152] The acquisition module 11 is used to acquire the open-circuit voltage of each cell in the battery cluster after the charging and discharging operation of the energy storage system is completed, so as to determine the state of charge corresponding to each cell.

[0153] The determining module 12 is also used to determine the target cell based on the charge and discharge state of the battery cluster;

[0154] The acquisition module 11 is further configured to acquire the initial balancing amount and the target balancing amount of the target battery cell based on the state of charge of the target battery cell; wherein, in the case where the state of charge of at least one battery cell is in a nonlinear region and the state of charge of at least one battery cell is in a linear region, for the target battery cell that satisfies the fuzzy calculation conditions, one of the values ​​of the initial balancing amount and the target balancing amount is determined by the endpoint value of the nonlinear region; the nonlinear region is the nonlinear region in the open-circuit voltage curve;

[0155] The determining module 12 is further configured to obtain the equalization amount of the target battery cell using the initial equalization amount and the target equalization amount of the target battery cell.

[0156] In one implementation, the determining module 12 includes:

[0157] The first determining submodule is used to identify at least one of the battery cells as the target battery cell when the battery cluster is in a discharge state.

[0158] In one implementation, when the battery cluster is in a discharging state, the acquisition module 11 includes:

[0159] The first acquisition submodule is used to, when the state of charge corresponding to the target cell is in a nonlinear region, take the minimum endpoint value in the nonlinear region as the initial balancing amount of the target cell, and take the lowest state of charge among all cells in the linear region as the target balancing amount of the target cell.

[0160] In one implementation, the determining module 12 includes:

[0161] The second determining submodule is used to select at least one of the cells whose state of charge is in the linear region as the target cell when the charge / discharge state of the battery cluster is charging.

[0162] In one implementation, when the battery cluster is in a charging state, the acquisition module 11 includes:

[0163] The second acquisition submodule is used to, when the state of charge of all battery cells is uneven in the linear region, take the state of charge of the target battery cell as the initial balancing quantity of the target battery cell, and take the maximum endpoint value in the nonlinear region as the target balancing quantity of the target battery cell.

[0164] In one implementation, the determining module 12 is specifically used for:

[0165] The difference between the initial balancing amount and the target balancing amount of the target battery cell is taken as the balancing amount of the target battery cell.

[0166] In one implementation, the equalization control device further includes:

[0167] The balancing module is used to perform a state-of-charge balancing operation between battery cells based on the balancing amount of the target battery cell.

[0168] Specifically, when the state of charge of the target cell is greater than the target equalization amount, the target cell is controlled to discharge until the state of charge of the target cell equals the target equalization amount.

[0169] In one implementation, the linear region is:

[0170] The open-circuit voltage curve represents the region where the open-circuit voltage of the battery cell is proportional to its state of charge.

[0171] In one implementation, the end of the energy storage system's charging and discharging operation includes: the energy storage system stopping the charging and discharging operation and the battery cells being left to stand still for a specified time.

[0172] In this embodiment, after the energy storage system's charging and discharging operations are completed, the open-circuit voltage of each cell in the battery cluster is acquired to determine the state of charge (SOC) corresponding to each cell. Based on the SOC of the battery cluster, a target cell is determined. Based on the SOC of the target cell, the initial equilibrium value and the target equilibrium value of the target cell are obtained. Where at least one cell's SOC is in a non-linear region and at least one cell's SOC is in a linear region, for a target cell that satisfies the fuzzy calculation conditions, one of the initial equilibrium value and the target equilibrium value is determined through the endpoint value of the non-linear region. This allows for accurate determination of the equilibrium value when the initial equilibrium value or the target equilibrium value of the cell cannot be accurately determined. By using the endpoint value of the non-linear region, a more accurate equilibrium value of the target cell can be obtained using the initial equilibrium value and the target equilibrium value. This enables SOC balancing operations to be performed based on the equilibrium value, reducing SOC differences between cells.

[0173] It should be noted that the working process of each module, submodule and unit in the embodiments of this application is described in the corresponding descriptions in the above embodiments, and will not be repeated here.

[0174] Another embodiment of this application provides a controller for performing the above-described equalization control method. The controller in this embodiment can be a cell controller, energy storage controller, etc.

[0175] Another embodiment of this application provides an equalization control system, including a battery cluster and the controller described above, wherein the controller controls the cells in the battery cluster to perform SOC equalization operation.

[0176] This application also provides a computer program product including computer-readable instructions, which, when executed on an electronic device, cause the electronic device to implement any of the equalization control methods provided in this application.

[0177] This application also provides a computer-readable storage medium that carries one or more computer programs. When the one or more computer programs are executed by an electronic device, the electronic device can implement any of the equalization control methods provided in this application.

[0178] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An equalization control method, characterized in that, include: After the energy storage system's charging and discharging operations are completed, the open-circuit voltage of each cell in the battery cluster is obtained to determine the state of charge corresponding to each cell. The target cell is determined based on the charge and discharge state of the battery cluster; Based on the state of charge of the target cell, the initial equalization amount and the target equalization amount of the target cell are obtained; wherein, in the case that at least one cell's state of charge is in a nonlinear region and at least one cell's state of charge is in a linear region, for the target cell that satisfies the fuzzy calculation conditions, one of the values ​​of the initial equalization amount and the target equalization amount is determined by the endpoint value of the nonlinear region; the nonlinear region is the nonlinear region in the open-circuit voltage curve. The equalization amount of the target battery cell is obtained by using the initial equalization amount and the target equalization amount of the target battery cell.

2. The equalization control method according to claim 1, characterized in that, Determining the target cell based on the charge / discharge state of the battery cluster includes: When the battery cluster is in a discharge state, at least one of the battery cells is selected as the target battery cell.

3. The equalization control method according to claim 2, characterized in that, When the battery cluster is in a discharging state, obtaining the initial balancing amount and target balancing amount of the target battery cell based on the state of charge of the target battery cell includes: When the state of charge corresponding to the target cell is in the nonlinear region, the minimum endpoint value in the nonlinear region is taken as the initial balancing amount of the target cell, and the lowest state of charge among all cells in the linear region is taken as the target balancing amount of the target cell.

4. The equalization control method according to claim 1, characterized in that, Determining the target cell based on the charge / discharge state of the battery cluster includes: When the charge / discharge state of the battery cluster is charging, at least one of the cells whose state of charge is in the linear region is selected as the target cell.

5. The equalization control method according to claim 4, characterized in that, When the battery cluster is in a charging state, obtaining the initial balancing amount and target balancing amount of the target battery cell based on the state of charge of the target battery cell includes: When the state of charge of all cells is unevenly distributed in the linear region, the state of charge of the target cell is used as the initial balancing quantity of the target cell, and the maximum endpoint value in the nonlinear region is used as the target balancing quantity of the target cell.

6. The equalization control method according to claim 1, characterized in that, The step of obtaining the balancing amount of the target battery cell using the initial balancing amount and the target balancing amount includes: The difference between the initial balancing amount and the target balancing amount of the target battery cell is taken as the balancing amount of the target battery cell.

7. The equalization control method according to any one of claims 1-6, characterized in that, After obtaining the equalization amount of the target battery cell, the method further includes: Perform a state-of-charge balancing operation between battery cells based on the balancing amount of the target battery cell; Specifically, when the state of charge of the target cell is greater than the target equalization amount, the target cell is controlled to discharge until the state of charge of the target cell equals the target equalization amount.

8. The equalization control method according to claim 3 or 5, characterized in that, The linear region is the area in the open-circuit voltage curve where the open-circuit voltage of the battery cell is proportional to its state of charge.

9. The equalization control method according to claim 1, characterized in that, The end of the energy storage system's charging and discharging operation includes: the energy storage system stopping the charging and discharging operation and the battery cells being left to stand for a specified time.

10. A balance control device, characterized in that, include: The acquisition module is used to acquire the open-circuit voltage of each cell in the battery cluster after the energy storage system charging and discharging operation is completed, so as to determine the state of charge corresponding to each cell. The determination module is also used to determine the target cell based on the charge and discharge state of the battery cluster; The acquisition module is further configured to acquire the initial balancing amount and the target balancing amount of the target battery cell based on the state of charge of the target battery cell; wherein, in the case where the state of charge of at least one battery cell is in a nonlinear region and the state of charge of at least one battery cell is in a linear region, for the target battery cell that satisfies the fuzzy calculation conditions, one of the values ​​of the initial balancing amount and the target balancing amount is determined by the endpoint value of the nonlinear region; the nonlinear region is the nonlinear region in the open-circuit voltage curve; The determining module is further configured to obtain the equalization amount of the target battery cell using the initial equalization amount and the target equalization amount of the target battery cell.

11. A controller, characterized in that, Used to perform the equalization control method as described in any one of claims 1 to 9.

12. A balanced control system, characterized in that, It includes a battery cluster and a controller as described in claim 11.

Images