Energy storage control device, system, and method

Abstract

This application relates to an energy storage control device, system, and method. The energy storage control device includes: an energy storage module comprising multiple battery cells, configured to be connected to a frequency converter module and configured to receive power from the frequency converter module or discharge power to the frequency converter module; and an equalization control module connected to the energy storage module, configured to: acquire a first target battery cell during the charging phase of the energy storage module; acquire a second target battery cell during the discharging phase of the energy storage module; determine a first priority of the first target battery cell and a second priority of the second target battery cell based on the state information of each battery cell; and perform equalization processing on the first target battery cell and the second target battery cell based on the first priority and the second priority of the second target battery cell; wherein the battery capacity of the first target battery cell is higher than that of the second target battery cell. This energy storage control device can reduce energy waste.

Description

Technical Field

[0001] This application relates to the field of elevator technology, and in particular to an energy storage control device, system and method. Background Technology

[0002] In related technologies, elevators are powered by mains electricity. When the mains power fails, the elevator cannot operate stably for an extended period, affecting daily work and life. At the same time, regenerative energy is generated when the elevator drives the main circuit.

[0003] The regenerative energy generated by elevators is currently processed by consuming resistors, resulting in significant energy waste. Summary of the Invention

[0004] Therefore, it is necessary to provide an energy storage control device, system, and method that can reduce energy waste in response to the above-mentioned technical problems.

[0005] In a first aspect, this application provides an energy storage control device, comprising:

[0006] An energy storage module, comprising multiple battery cells, is configured to connect to a frequency converter module and to receive power from the frequency converter module or discharge power to the frequency converter module.

[0007] The equalization control module, connected to the energy storage module, is configured to connect to the frequency converter module and is configured as follows:

[0008] During the charging phase of the energy storage module, the first target battery cell is acquired;

[0009] During the discharge phase of the energy storage module, a second target battery cell is acquired;

[0010] Based on the status information of each battery cell, determine the first priority of the first target battery cell and the second priority of the second target battery cell;

[0011] Based on the first priority of the first target battery cell and the second priority of the second target battery cell, a balancing process is performed on the first target battery cell and the second target battery cell.

[0012] The cell capacity of the first target cell is higher than that of the second target cell.

[0013] In one embodiment, the target phase includes the charging phase and the discharging phase, and the target battery cell includes the first target battery cell and the second target battery cell;

[0014] The equalization control module executes the target phase of the energy storage module, acquires the target battery cell, and is configured as follows:

[0015] During the charging phase, based on the charging current between the energy storage module and the frequency conversion module and the status information of each battery cell within a first preset time period, a plurality of first candidate battery cells are obtained from a plurality of battery cells.

[0016] During the discharge phase, based on the discharge current between the energy storage module and the frequency conversion module and the status information of each battery cell, a plurality of second candidate batteries are obtained from the plurality of battery cells.

[0017] If a battery cell is a first candidate battery cell during the charging phase and a second candidate battery cell during the adjacent discharging phase, the battery cell is identified as an abnormal battery cell.

[0018] The first candidate cell among the multiple first candidate cells, excluding the abnormal cell, is determined as the first target cell;

[0019] The second candidate cell, excluding the abnormal cell, is selected as the second target cell from among the multiple second candidate cells.

[0020] In one embodiment, the state information includes the individual cell voltage; the first preset time period includes multiple first sampling times; the candidate cell includes the first candidate cell or the second candidate cell; and the target current includes the charging current or the discharging current.

[0021] The equalization control module executes the target current between the energy storage module and the frequency converter module and the status information of each battery cell within a first preset time period, and obtains multiple candidate battery cells from the multiple battery cells, which are configured as follows:

[0022] Based on the target current within the first preset time period and the individual voltage of each cell, multiple current differences and multiple first voltage differences are obtained; the current difference is the difference between the target currents at two adjacent first sampling times, and the first voltage difference is the difference between the maximum and minimum values ​​of the individual voltages of the same cell within the first preset time period.

[0023] When multiple consecutive current differences are less than a preset current threshold and multiple consecutive first voltage differences are less than a preset voltage threshold, a second voltage difference corresponding to each cell is obtained based on the individual cell voltage at the target first sampling time; the target first sampling time is the last first sampling time within the first preset time period, and the second voltage difference is the difference between the individual cell voltage at the target first sampling time and the minimum value among the individual cell voltages at the target first sampling time;

[0024] The cell corresponding to the second voltage difference that meets the preset equalization condition is determined as the candidate cell;

[0025] Wherein, when the candidate cell is the first candidate cell and the target current is the charging current, the preset equalization condition includes the second voltage difference being greater than the preset equalization threshold; when the candidate cell is the second candidate cell and the target current is the discharging current, the preset equalization condition includes the second voltage difference being less than the preset equalization threshold.

[0026] In one embodiment, the device further includes:

[0027] A current stabilizing module is connected to the energy storage module and configured to connect to the frequency converter module, and is also configured to stabilize the charging and discharging current between the energy storage module and the frequency converter module.

[0028] In one embodiment, the current stabilization module includes:

[0029] A first impedance adjustment unit, wherein a first end of the first impedance adjustment unit is connected to the energy storage module, a second end of the first impedance adjustment unit is used to connect to the frequency conversion module, and a control end of the first impedance adjustment unit is connected to the equalization control module;

[0030] The equalization control module is further configured to output a current stabilization control signal to the first impedance regulation unit based on the first voltage information of the energy storage module and the second voltage information of the frequency conversion module, so as to control the equivalent impedance of the first impedance regulation unit.

[0031] In one embodiment, the current stabilization module includes:

[0032] The second impedance adjustment unit, the first end of which is connected to the energy storage module;

[0033] The third impedance adjustment unit has a first end connected to the second end of the second impedance adjustment unit, and the second end of the third impedance adjustment unit is connected to the frequency converter module.

[0034] The feedback unit has a first input terminal connected to the first terminal of the third impedance adjustment unit, a second terminal connected to the second terminal of the third impedance adjustment unit, and an output terminal connected to the control terminal of the second impedance adjustment unit. The feedback unit is used to output a feedback signal based on the voltage difference across the third impedance adjustment unit to control the equivalent impedance of the second impedance adjustment unit.

[0035] In one embodiment, the control terminal of the third impedance adjustment unit is connected to the equalization control module;

[0036] The equalization control module is also used to acquire temperature information of the second impedance adjustment unit and the third impedance adjustment unit, and to output a short-circuit control signal to the third impedance adjustment unit when the temperature information exceeds a preset temperature threshold, so as to short-circuit the second impedance adjustment unit and the third impedance adjustment unit.

[0037] In one embodiment, before the equalization control module determines the first priority of the first target cell and the second priority of the second target cell based on the state information of each cell, it is further configured to:

[0038] During the resting phase of the energy storage module, the capacity index of each cell is obtained based on the individual cell voltage and individual cell temperature.

[0039] If the capacity index of a battery cell is less than a preset first capacity threshold, the capacity difference value corresponding to each battery cell is obtained; the capacity difference value is the difference between the minimum value of the capacity index of each battery cell and the capacity index of the battery cell.

[0040] Cells with a capacity difference greater than a preset second capacity threshold are identified as first target cells, and cells with a capacity difference less than or equal to the preset second capacity threshold are identified as second target cells.

[0041] Secondly, this application provides an energy storage control system, including a load, a frequency converter connected to the load, and the energy storage control device described in any of the above embodiments.

[0042] Thirdly, this application provides an energy storage control method, applied to the energy storage control device described in any of the above embodiments, the method comprising:

[0043] During the charging phase of the energy storage module, the first target battery cell is acquired;

[0044] During the discharge phase of the energy storage module, a second target battery cell is acquired;

[0045] Based on the status information of each battery cell, determine the first priority of the first target battery cell and the second priority of the second target battery cell;

[0046] Based on the first priority of the first target battery cell and the second priority of the second target battery cell, a balancing process is performed on the first target battery cell and the second target battery cell.

[0047] The cell capacity of the first target cell is higher than that of the second target cell.

[0048] The aforementioned energy storage control device, system, and method include an energy storage module connected to a frequency converter module. This module can recover and store the regenerative energy generated by the frequency converter module, rather than dissipating it through resistors, thereby significantly improving energy utilization efficiency and achieving energy saving. Furthermore, this application also includes a balancing control module. This module can identify a first target cell during the charging phase and a second target cell during the discharging phase of the energy storage module. It can utilize the characteristics that cells with higher capacity are more likely to fully charge and have higher voltage during the charging phase, while cells with lower capacity are more likely to fully discharge and have lower voltage during the discharging phase, to accurately identify the first and second target cells in the energy storage module. Based on the state information of the first and second target cells, they are prioritized and balancing is performed according to their priority, which improves balancing efficiency. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 This is a schematic diagram of the energy storage control system in one embodiment;

[0051] Figure 2 This is a schematic diagram of the energy storage control system in another embodiment;

[0052] Figure 3 This is a schematic diagram of the energy storage control system in another embodiment;

[0053] Figure 4 This is a schematic diagram of the energy storage control system in another embodiment. Detailed Implementation

[0054] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0055] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0056] Battery balancing technologies fall into two main categories: balancing strategies based on resting voltage and balancing strategies based on battery models. The resting voltage-based balancing strategy utilizes the deterministic relationship between the battery's open-circuit voltage (OCV) and state of charge (SOC) in a current-free (resting) state. It indirectly calculates SOC differences by measuring OCV, thereby implementing balancing. The battery model-based balancing strategy estimates the battery's actual state (e.g., SOC, SOH, internal resistance, etc.) in real time using mathematical models. It performs balancing based on state differences rather than simple voltage differences, thus accurately identifying inconsistencies between batteries even under dynamic operating conditions.

[0057] However, the equalization strategy based on resting voltage has two fundamental flaws: dependence on resting conditions and unclear voltage characteristics in the plateau region. When faced with systems that have not been rested for a long time and whose battery SOC remains at a plateau for an extended period, it is difficult to accurately determine the differences between batteries because the voltage and other characteristics of the batteries are very similar when the SOC is between 30% and 70%.

[0058] The balancing strategy based on battery models faces a contradiction between model dependency and data requirements. A complete battery model requires complete charge-discharge curves (0-100% SOC), characteristic data at multiple temperature points (-20℃ to 60℃), performance data at different rates (0.1C to 2C), aging cycle data (hundreds to thousands of cycles), and a sufficiently long resting time for parameter identification. However, the data from elevator energy recovery systems suffers from problems such as small SOC changes per pulse (<1%), lack of complete charge-discharge cycles, and drastic current changes, leading to difficulty in model convergence, insufficient resting time, and inability to obtain OCV. In other words, building a battery model requires continuous, long-term charge-discharge data, while energy recovery systems like elevator energy-saving systems have very short periods of power generation and consumption. This makes it difficult to build an accurate battery model.

[0059] In summary, these problems are particularly prominent in electromechanical equipment that can generate renewable energy recovery, such as elevators, elevator energy recovery systems, hybrid vehicles, and drones, which are dynamic pulse-type applications. This results in the balancing strategies in related technologies having limited effectiveness or even being completely ineffective in these scenarios.

[0060] To address the above technical problems, please refer to some exemplary embodiments. Figure 1 This application provides an energy storage control device 100, comprising:

[0061] The energy storage module 10 includes multiple battery cells, is configured to connect to the frequency converter module 200, and is configured to receive power from the frequency converter module 200 or discharge power to the frequency converter module 200.

[0062] The equalization control module 20, connected to the energy storage module 10, is configured to connect to the frequency converter module 200 and is configured as follows:

[0063] During the charging phase of the energy storage module 10, the first target battery cell is acquired;

[0064] During the discharge phase of the energy storage module 10, the second target battery cell is acquired;

[0065] Based on the status information of each cell, determine the first priority of the first target cell and the second priority of the second target cell;

[0066] Based on the first priority of the first target battery cell and the second priority of the second target battery cell, the first target battery cell and the second target battery cell are subjected to equalization processing;

[0067] Among them, the cell capacity of the first target cell is higher than that of the second target cell.

[0068] In this embodiment, the energy storage module 10 serves as the system's energy buffer and can employ supercapacitors or power batteries to handle the instantaneous high-power charging and discharging surges required by special equipment, such as elevators, during operation, thus preventing impacts on the power grid. Alternatively, it can use energy-type battery packs, including but not limited to lithium batteries, sodium batteries, and accumulators, to continuously replenish the power-type battery packs and special equipment or to continuously charge them in reverse, meeting the continuous power consumption and regenerative energy recovery needs of special equipment. In one example, the energy storage module 10 may include multiple cells connected in series.

[0069] The equalization control module 20 can acquire the current and voltage information of each cell in the energy storage module 10, thereby obtaining the total current and total voltage information of the energy storage module 10. The voltage information indicates the magnitude of the cell voltage, the current information indicates the magnitude of the cell current, the total current information indicates the overall current of the energy storage module 10, and the total voltage information indicates the overall voltage of the energy storage module 10. Where all the cells in the energy storage module 10 are connected in series, the current magnitude of each cell is the same, and the current magnitude of any single cell is equal to the overall current of the energy storage module 10. The sum of the voltages of all the cells in the energy storage module 10 is the total voltage of the energy storage module 10.

[0070] In the application, during the charging phase of the energy storage module 10, the energy storage module 10 receives power from the frequency converter module 200; during the discharging phase of the energy storage module 10, the energy storage module 10 discharges to the frequency converter module 200. During the charging phase of the energy storage module 10, the equalization control module can identify a first target cell based on the total current information of the energy storage module and the voltage information of each cell. The first target cell can be a target high-capacity cell. Furthermore, during the discharging phase of the energy storage module 10, the equalization control module can identify a second target cell based on the total current information of the energy storage module and the voltage information of each cell. The second target cell can be a target low-capacity cell. It is understood that high-capacity cells experience a faster voltage rise during charging and are more likely to reach full charge voltage first, while low-capacity cells experience a faster voltage drop during discharging and are more likely to discharge completely first. Therefore, this application utilizes the characteristics of cells at different operating stages to accurately identify the first and second target cells.

[0071] After identifying the first or second target battery cell, the equalization control module 20 can estimate the equalization time for each target cell based on its status information. In practice, since equalization may not be possible simultaneously, it is necessary to prioritize these target cells. For example, the individual cell charge and temperature of the first and second target cells can be collected, and priority can be determined by looking up a table. This step dynamically calculates which high-capacity cell most needs to stop charging (first priority) and which low-capacity cell most needs to be discharged (second priority). This targeted and prioritized equalization strategy ensures that limited equalization energy (passive equalization dissipation or active equalization transfer) is used on the cells that need it most, thereby improving equalization efficiency, reducing unnecessary energy loss, and extending the lifespan of the energy storage module.

[0072] In applications, battery balancing can be performed using active balancing, passive balancing, or a combination of both.

[0073] For example, if the energy storage module only has the function of passive balancing, it can find the Q cells with the highest priority according to their first priority, and start passive balancing for these cells, where Q>1.

[0074] If the energy storage module only has the function of active balancing, it can select the Q cells with the highest priority and the Q cells with the lowest capacity from the first target cell and the second target cell, and activate active balancing for these 2Q cells, so that the first target cell with the highest capacity can charge the second target cell with the lowest capacity.

[0075] If the energy storage module has both active and passive balancing capabilities, and only the first target cell is identified but the second target cell is not, then for the identified first target cell, the highest priority Q cells are selected according to their first priority, and passive balancing is initiated for these cells. If both the first and second target cells are identified, the highest priority Q cells with higher capacity and P cells with lower capacity are selected, and active balancing is initiated for these Q+P cells, allowing the higher-capacity first target cell to charge the lower-capacity second target cell. If both the first and second target cells are identified, but the active balancing channels are insufficient, the priority sorting module selects the highest priority Q cells with higher capacity and P cells with lower capacity, initiates active balancing for these Q+P cells, and simultaneously initiates passive balancing for the remaining higher-capacity cells, where P > 1.

[0076] The aforementioned energy storage control device, system, and method include an energy storage module connected to a frequency converter module. This module can recover and store the regenerative energy generated by the frequency converter module, rather than dissipating it through resistors, thereby significantly improving energy utilization efficiency and achieving energy saving. Furthermore, this application also includes a balancing control module. This module can identify a first target cell during the charging phase and a second target cell during the discharging phase of the energy storage module. It can utilize the characteristics that cells with higher capacity are more likely to fully charge and have higher voltage during the charging phase, while cells with lower capacity are more likely to fully discharge and have lower voltage during the discharging phase, to accurately identify the first and second target cells in the energy storage module. Based on the state information of the first and second target cells, they are prioritized and balancing is performed according to their priority, which improves balancing efficiency.

[0077] In some exemplary embodiments, please refer to Figure 2 The device also includes:

[0078] The current stabilizing module 30 is connected to the energy storage module 10 and configured to be connected to the frequency converter module 200. It is also configured to stabilize the charging and discharging current between the energy storage module 10 and the frequency converter module 200.

[0079] In one example, one end of the current stabilizing module 30 is connected to the positive terminal of the energy storage module 10, and the other end of the current stabilizing module 30 is connected to the positive DC bus of the frequency converter module 200. Alternatively, in another example, one end of the current stabilizing module 30 is connected to the negative terminal of the energy storage module 10, and the other end of the current stabilizing module 30 is connected to the negative DC bus of the frequency converter module 200.

[0080] It is understandable that in the energy storage control system, the operating characteristics of the inverter module 200 will cause severe, high-frequency fluctuations in the charging and discharging current between the energy storage module 10 and the inverter module 200. For example, the high-speed switching action of the IGBT (Insulated Gate Bipolar Transistor) inside the inverter will generate high-frequency ripple current. Similarly, the starting, accelerating, decelerating, and stopping actions of an elevator will cause instantaneous and significant changes in motor power, resulting in a sharp step change in current. These fluctuations in charging and discharging current will cause fluctuations in the current and voltage of the battery cells detected by the equalization control module, leading to an inability to accurately detect high-capacity and low-capacity cells, thus hindering battery equalization.

[0081] Therefore, this application includes a current stabilization module 30, which can stabilize and smooth the current, providing a stable measurement environment for the equalization control module. This allows the measured cell voltage to more accurately reflect its internal state of charge and polarization, improving the accuracy of the state information. Simultaneously, it can extend the service life of the energy storage module.

[0082] In some exemplary embodiments, please refer to Figure 3 The current stabilization module 30 includes:

[0083] The first impedance adjustment unit 31 has a first end connected to the energy storage module 10, a second end connected to the frequency conversion module, and a control end connected to the equalization control module 20.

[0084] The equalization control module 20 is also configured to output a steady current control signal to the first impedance adjustment unit 31 based on the first voltage information of the energy storage module 10 and the second voltage information of the frequency conversion module 200, so as to control the equivalent impedance of the first impedance adjustment unit 31.

[0085] The first voltage information is used to indicate the total voltage of the energy storage module 10, and the second voltage information is used to indicate the voltage of the frequency converter module 200.

[0086] In one example, the first impedance adjustment unit 31 may include a first switching transistor M1, the first terminal of the first switching transistor M1 is connected to the energy storage module 10, the second terminal of the first switching transistor M1 is connected to the frequency conversion module 200, and the gate of the first switching transistor M1 is connected to the equalization control module 20.

[0087] In the application, the equalization control module 20 can output a current stabilization control signal to the first impedance adjustment unit 31 to control the conduction level of the first switching transistor M1, that is, to control the equivalent impedance of the first switching transistor M1, thereby controlling the magnitude of the charging and discharging current between the energy storage module 10 and the frequency converter module 200. For example, when the voltage difference between the total voltage of the energy storage module and the voltage of the frequency converter module 200 increases, the charging and discharging current between the energy storage module 10 and the frequency converter module 200 also increases. At this time, the equalization control module 20 can control the equivalent impedance of the first switching transistor M1 to increase, thereby stabilizing the charging and discharging current.

[0088] In some exemplary embodiments, the current stabilization module 30 includes:

[0089] The second impedance adjustment unit 32, the first end of the second impedance adjustment unit 32 is connected to the energy storage module 10;

[0090] The third impedance adjustment unit 33 has a first end connected to the second end of the second impedance adjustment unit 32, and the second end of the third impedance adjustment unit 33 is connected to the frequency converter module 200.

[0091] Feedback unit 34 has its first input terminal connected to the first terminal of the third impedance adjustment unit 33, its second terminal connected to the second terminal of the third impedance adjustment unit 33, and its output terminal connected to the control terminal of the second impedance adjustment unit 32. The feedback unit 34 is used to output a feedback signal based on the voltage difference across the third impedance adjustment unit 33 to control the equivalent impedance of the second impedance adjustment unit 32.

[0092] In this embodiment, the second impedance adjustment unit 32 may include a second switching transistor M2, the first terminal of which is connected to the energy storage module 10. The third impedance adjustment unit 33 may include a third switching transistor M3, the first terminal of which is connected to the second terminal of the second switching transistor M2, and the second terminal of which is connected to the frequency conversion module 200. The feedback unit 34 may include an operational amplifier V1, the first input terminal of which is connected to the first terminal of the third switching transistor M3, the second terminal of which is connected to the second terminal of the third switching transistor M3, and the output terminal of which is connected to the gate of the second switching transistor M2.

[0093] When the equivalent impedance of the third switch M3 is determined, if the charging and discharging current between the energy storage module 10 and the frequency converter module 200 increases, the voltage difference between the first and second terminals of the third switch M3 will increase, which in turn will reduce the feedback signal output by the operational amplifier V1, increase the equivalent impedance of the second switch M2, and thus reduce the charging and discharging current between the energy storage module 10 and the frequency converter module 200, thereby achieving current stability.

[0094] In some exemplary embodiments, please continue to refer to Figure 4 The control terminal of the third impedance adjustment unit 33 is connected to the equalization control module 20;

[0095] The equalization control module 20 is also used to acquire the temperature information of the second impedance adjustment unit 32 and the third impedance adjustment unit 33, and to output a short-circuit control signal to the third impedance adjustment unit 33 when the temperature information exceeds a preset temperature threshold, so as to short-circuit the second impedance adjustment unit 32 and the third impedance adjustment unit 33.

[0096] In the application, the equalization control module 20 can also monitor the temperature of the second impedance adjustment unit 32 and the third impedance adjustment unit 33 in real time. When the second impedance adjustment unit 32 and / or the third impedance adjustment unit 33 overheats severely, the equalization control module 20 can control the equivalent impedance of the third switching transistor M3 to become 0, making the voltage difference between the first and second terminals of the third switching transistor M3 zero. This, in turn, increases the feedback signal output by the operational amplifier V1, making the equivalent impedance of the second switching transistor M2 zero, thus short-circuiting the second impedance adjustment unit 32 and the third impedance adjustment unit 33, equivalent to a wire. In the application, when the temperature of the second impedance adjustment unit 32 and the third impedance adjustment unit 33 returns to normal, the equalization control module 20 can again control the equivalent impedance of the third switching transistor M3 to increase, thereby initiating current stabilization.

[0097] In the application, the magnitude of the charging and discharging current is related to the magnitude of the equivalent impedance of the third switch M3. The equalization control module 20 can control the magnitude of the charging and discharging current by controlling the magnitude of the equivalent impedance of the third switch M3.

[0098] In one example, current stabilization can be activated only when the magnitude of the charging and discharging current exceeds a preset safety threshold; otherwise, current stabilization can be omitted.

[0099] In some exemplary embodiments, the target stage includes a charging stage and a discharging stage, and the target battery cell includes a first target battery cell and a second target battery cell;

[0100] The balancing control module executes during the target phase of the energy storage module, acquires the target battery cell, and is configured as follows:

[0101] During the charging phase, based on the charging current between the energy storage module and the frequency conversion module and the status information of each cell within the first preset time period, multiple first candidate cells are obtained from multiple cells.

[0102] During the discharge phase, multiple second candidate cells are obtained from multiple cells based on the discharge current between the energy storage module and the frequency conversion module and the status information of each cell.

[0103] If a cell is the first candidate cell during the charging phase and the second candidate cell during the adjacent discharging phase, the cell is identified as an abnormal cell.

[0104] The first candidate cell among multiple first candidate cells, excluding the abnormal cell, is determined as the first target cell;

[0105] The second candidate cell, excluding the abnormal cell, is selected as the second target cell from among multiple second candidate cells.

[0106] In determining the first and second candidate battery cells, this application does not rely on a single instantaneous value during the charging and discharging phases. Instead, it comprehensively determines the cells based on the charging / discharging current between the energy storage module and the frequency converter module, along with the status information of each cell within a first preset time period. By introducing a time window of the first preset time period, the randomness and noise interference of single-point sampling can be avoided.

[0107] In one example, after identifying the first candidate cell during the charging phase, the equalization control module 20 can further determine whether the first candidate cell identified in this charging phase was marked as the second candidate cell in the adjacent previous discharging phase. If it was marked as the second candidate cell, meaning that the cell had a high single-cell voltage during charging and was marked as the first candidate cell, but a low single-cell voltage during discharging and was marked as the second candidate cell, it indicates that the cell's capacity has degraded and is less than that of other cells. Therefore, the cell does not actually have a high capacity, but has been misidentified by the strategy. Thus, the cell can be marked as an abnormal cell. For abnormal cells, the equalization control module can issue a prompt message to remind relevant technicians to replace the abnormal cell. First candidate cells that were not marked as abnormal cells can be identified as the first target cell.

[0108] Similarly, after identifying the second candidate cell during the discharge phase, the equalization control module 20 can further determine whether the second candidate cell identified in this discharge phase was marked as the first candidate cell in the adjacent previous charging phase. If it was marked as the first candidate cell, it can be marked as an abnormal cell. For abnormal cells, the equalization control module can issue a prompt message to remind relevant technicians to replace the abnormal cell. Second candidate cells that were not marked as abnormal cells can be identified as the second target cell.

[0109] In some exemplary embodiments, the status information includes the individual cell voltage; the first preset time period includes multiple first sampling times; the candidate cell includes a first candidate cell or a second candidate cell; and the target current includes the charging current or the discharging current.

[0110] The equalization control module executes the target current and the status information of each cell between the energy storage module and the frequency converter module within a first preset time period, and obtains multiple candidate cells from multiple cells, which are configured as follows:

[0111] Based on the target current and the individual voltage of each cell within the first preset time period, multiple current differences and multiple first voltage differences are obtained; the current difference is the difference between the target currents at two adjacent first sampling times, and the first voltage difference is the difference between the maximum and minimum values ​​of the individual voltages of the same cell within the first preset time period.

[0112] When multiple consecutive current differences are less than a preset current threshold and multiple consecutive first voltage differences are less than a preset voltage threshold, the second voltage difference corresponding to each cell is obtained based on the individual cell voltage at the target first sampling time; the target first sampling time is the last first sampling time within the first preset time period, and the second voltage difference is the difference between the individual cell voltage at the target first sampling time and the minimum value among the individual cell voltages at the target first sampling time.

[0113] The cell corresponding to the second voltage difference that meets the preset equalization condition is identified as a candidate cell.

[0114] Specifically, when the candidate cell is the first candidate cell and the target current is the charging current, the preset equalization condition includes a second voltage difference greater than a preset equalization threshold; when the candidate cell is the second candidate cell and the target current is the discharging current, the preset equalization condition includes a second voltage difference less than a preset equalization threshold.

[0115] In one embodiment, taking the candidate battery cell as the first candidate battery cell and the target current as the charging current as an example, it is assumed that the first preset time period includes x first sampling moments, and the energy storage module includes y battery cells connected in series. During the charging phase, the equalization control module 20 can continuously collect the charging current I: I1, I2, ..., I... x times. x And at each first sampling moment, the individual cell voltage V:V 11 V 12 ... V 1x V 21 V 22 ... V 2x V y1 V y2 ... V yx , where V 11 This represents the single-cell voltage (V) of the first battery cell at the first sampling moment within the first preset time period. 12 This represents the single-cell voltage (V) of the first battery cell at the second first sampling moment within the first preset time period. 1xThis represents the single-cell voltage (V) of the first cell at the x-th sampling moment within the first preset time period. 21 This represents the individual cell voltage (V) at the first sampling moment within the first preset time period of the second battery cell. 22 This represents the individual cell voltage (V) at the second sampling moment within the first preset time period. 2x This represents the single-cell voltage (V) of the second battery cell at the x-th first sampling moment within the first preset time period. y1 V represents the single-cell voltage of the y-th cell at the first sampling moment within the first preset time period. y2 V represents the individual voltage of the y-th cell at the second first sampling moment within the first preset time period. yx This represents the individual voltage of the y-th cell at the x-th first sampling moment within the first preset time period.

[0116] Subsequently, the equalization control module can calculate multiple current differences ΔI of the charging current within the first preset time period. The current difference ΔI is the difference between the charging current at a first sampling moment and the charging current at the previous first sampling moment. For example, ΔI1 = I2 - I1, ΔI2 = I3 - I2, ..., ΔI x-1 =I x -I x-1 .

[0117] Simultaneously, the equalization control module can also calculate the first voltage difference ΔV of each cell within the first preset time period. 1 The first voltage difference ΔV 1 The difference between the maximum and minimum voltage values ​​of each individual cell within the same battery cell during a first preset time period, for example, , ... ,in, V represents the first voltage difference of the first cell. 1max V represents the maximum value of the individual cell voltages within the first preset time period for the first cell. 1min This refers to the minimum voltage among all individual cells in the first battery cell within a first preset time period. V represents the first voltage difference of the second cell. 2max V represents the maximum value of the individual cell voltages within the first preset time period for the second cell. 2min This is the minimum value of the individual cell voltages of the second cell within the first preset time period. V represents the first voltage difference of the y-th cell. ymax V represents the maximum voltage of each cell in the y-th cell during the first preset time period. yminLet y be the minimum voltage of each individual cell within the first preset time period. If the first voltage difference of each cell within the first preset time period is less than the preset voltage threshold, then the individual cell voltage data collected by the equalization control module can be determined to be true and valid.

[0118] If the individual cell voltage data of each battery cell is true and valid, and the current difference ΔI at each of the s consecutive first sampling moments is less than the preset current threshold, i.e., the charging current is stable, then the individual cell voltages at the last first sampling moment (i.e., the xth first sampling moment) within the first preset time period can be sorted to determine the minimum value V among the individual cell voltages at the last first sampling moment within the first preset time period. min Next, the individual cell voltage and V at the first sampling time for each target are calculated. min The second voltage difference ΔV 2 For example, , ... ,in, This is the second voltage difference value of the first cell in the energy storage module. V represents the single-cell voltage of the first cell in the energy storage module at the xth sampling moment. min Let be the minimum value among the individual voltages of each cell at the x-th first sampling time. This is the second voltage difference value of the second cell in the energy storage module. Let be the individual cell voltage of the second cell in the energy storage module at the xth first sampling moment. This represents the second voltage difference of the y-th cell in the energy storage module. Let be the voltage of the y-th cell in the energy storage module at the x-th first sampling moment, where 1 < s ≤ x.

[0119] After calculating the second voltage difference of each cell, it can be compared whether the second voltage difference of each cell is greater than a preset equalization threshold. If there is a cell whose second voltage difference is greater than the preset equalization threshold, it indicates that the cell has a higher voltage and may be a high-capacity cell, thus it can be identified as the first candidate cell. In application, the number of first candidate cells can be finite, for example, M. When the number of first candidate cells is finite, the judgment can start from the cell with the largest single voltage at the x-th sampling time. Once M first candidate cells are determined, the determination of first candidate cells can be stopped.

[0120] In another example, taking the second candidate cell as the candidate cell and the discharge current as the target current, let's assume the first preset time period includes x first sampling moments, and the energy storage module includes y cells connected in series. During the discharge phase, the equalization control module 20 can continuously collect x discharge currents I: I1, I2, ..., I... xAnd at each first sampling moment, the individual cell voltage V:V 11 V 12 ... V 1x V 21 V 22 ... V 2x V y1 V y2 ... V yx .

[0121] Subsequently, the equalization control module can calculate multiple current differences ΔI of the charging current within the first preset time period, and calculate the first voltage difference ΔV at each first sampling moment within the first preset time period. 1 Assuming the individual cell voltage data is accurate and valid, and the discharge current is stable, the individual cell voltages at the last sampling time (i.e., the xth sampling time) within the first preset time period can be sorted to determine the minimum value V among the individual cell voltages at the last sampling time within the first preset time period. min And calculate the second voltage difference ΔV for each cell. 2 .

[0122] After calculating the second voltage difference of each cell, it can be compared whether the second voltage difference of each cell is less than a preset equalization threshold. If there is a cell whose second voltage difference is less than the preset equalization threshold, it indicates that the cell has a low voltage and may be a low-capacity cell, thus it can be identified as a second candidate cell. In application, the number of second candidate cells can be finite, for example, M. When the number of first candidate cells is finite, the determination can start from the cell with the smallest single-cell voltage at the x-th first sampling time. Once M second candidate cells are determined, the determination of second candidate cells can be stopped.

[0123] In one embodiment, the charging current can be positive and the discharging current can be negative.

[0124] It is understood that when the energy storage control device in this application is equipped with a current stabilization module, the magnitude of the charging current and the discharging current will be more stable than when the energy storage control device does not have a current stabilization module, thereby making it easier to trigger battery balancing, which helps to increase the number of times battery balancing is triggered and improve the efficiency of battery balancing.

[0125] In some exemplary embodiments, before the equalization control module 20 performs the task of determining the first priority of the first target cell and the second priority of the second target cell based on the state information of each cell, it is further configured to:

[0126] During the resting phase of the energy storage module 10, the capacity index of each cell is obtained based on the individual cell voltage and temperature.

[0127] If the capacity index of a cell is less than a preset first capacity threshold, obtain the capacity difference for each cell; the capacity difference is the difference between the minimum capacity index of each cell and the capacity index of the cell.

[0128] Cells with a capacity difference greater than a preset second capacity threshold are identified as first target cells, and cells with a capacity difference less than or equal to the preset second capacity threshold are identified as second target cells.

[0129] In application, in order to improve the efficiency of battery balancing, this application can perform battery balancing not only during the charging and discharging phases of the energy storage module 10, but also during the resting phase of the energy storage module 10.

[0130] Specifically, when the equalization control module 20 can monitor the magnitude of the charging and discharging current in real time, and when the absolute values ​​of multiple consecutive charging and discharging currents are all less than a preset resting current threshold, it can be determined that the energy storage module 10 is in a resting phase. Furthermore, the equalization control module can determine the capacity index of each cell based on its individual cell voltage and temperature, and according to a preset open-circuit voltage information database. For example, , ... ,in, This represents a preset open-circuit voltage information database. This refers to the voltage of the first cell in the energy storage module. This refers to the temperature of the first battery cell in the energy storage module. To find the capacity index of the first cell in the energy storage module determined by the open-circuit voltage information database based on the individual cell voltage and temperature of the first cell. This refers to the individual voltage of the second cell in the energy storage module. This refers to the temperature of the second cell in the energy storage module. To find the capacity index of the second cell in the energy storage module determined by the open-circuit voltage information database based on the individual cell voltage and temperature of the second cell. Let be the voltage of the y-th cell in the energy storage module. Let be the temperature of the y-th cell in the energy storage module. To find the capacity index of the y-th cell in the energy storage module determined by the open-circuit voltage information database based on the individual cell voltage and temperature of the y-th cell.

[0131] Next, the minimum value C among the capacity indices of each cell can be determined. min If the minimum value of the capacity index of each cell is less than a preset first capacity threshold, equalization identification can be initiated: calculate the capacity difference ΔC corresponding to each cell, for example, ΔC1=C1-C min ΔC2=C2-Cmin ... ΔC y =C y -C min Where ΔC1 is the capacity difference of the first cell in the energy storage module, ΔC2 is the capacity difference of the second cell in the energy storage module, and ΔC y This represents the capacity difference of the y-th cell in the energy storage module.

[0132] Cells with a capacity difference greater than a preset second capacity threshold are identified as the first target cell. Cells with a capacity difference less than or equal to the preset second capacity threshold are identified as the second target cell.

[0133] In one example, this application can also determine the equalization time for the first target cell and the second target cell: Where Time is the time to be balanced, and C is the capacity exponent. The preset rated capacity of the battery cell, This is the preset equalization current.

[0134] In some exemplary embodiments, this application provides an energy storage control system, including a load, a frequency converter connected to the load, and an energy storage control device as described in any of the above embodiments.

[0135] The load may include elevators, or loads with similar operating characteristics to elevators, such as elevators, oil pumps, etc., which can generate regenerative energy and recycle it while consuming electricity.

[0136] In some exemplary embodiments, this application provides an energy storage control method, applied to the energy storage control device in any of the above embodiments, the method comprising:

[0137] During the charging phase of the energy storage module, the first target battery cell is acquired;

[0138] During the discharge phase of the energy storage module, the second target battery cell is acquired;

[0139] Based on the status information of each cell, determine the first priority of the first target cell and the second priority of the second target cell;

[0140] Based on the first priority of the first target battery cell and the second priority of the second target battery cell, the first target battery cell and the second target battery cell are subjected to equalization processing;

[0141] Among them, the cell capacity of the first target cell is higher than that of the second target cell.

[0142] In the description of this specification, references to terms such as "some embodiments," "other embodiments," and "ideal embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0143] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0144] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An energy storage control device, characterized in that, include: An energy storage module, comprising multiple battery cells, is configured to connect to a frequency converter module and to receive power from the frequency converter module or discharge power to the frequency converter module. The equalization control module, connected to the energy storage module, is configured to connect to the frequency converter module and is configured as follows: During the charging phase of the energy storage module, the first target battery cell is acquired; During the discharge phase of the energy storage module, a second target battery cell is acquired; Based on the status information of each battery cell, determine the first priority of the first target battery cell and the second priority of the second target battery cell; Based on the first priority of the first target battery cell and the second priority of the second target battery cell, a balancing process is performed on the first target battery cell and the second target battery cell. The cell capacity of the first target cell is higher than that of the second target cell.

2. The energy storage control device according to claim 1, characterized in that, The target phase includes the charging phase and the discharging phase, and the target battery cell includes the first target battery cell and the second target battery cell; The equalization control module executes the target phase of the energy storage module, acquires the target battery cell, and is configured as follows: During the charging phase, based on the charging current between the energy storage module and the frequency conversion module and the status information of each battery cell within a first preset time period, a plurality of first candidate battery cells are obtained from a plurality of battery cells. During the discharge phase, based on the discharge current between the energy storage module and the frequency conversion module and the status information of each battery cell, a plurality of second candidate batteries are obtained from the plurality of battery cells. If a battery cell is a first candidate battery cell during the charging phase and a second candidate battery cell during the adjacent discharging phase, the battery cell is identified as an abnormal battery cell. The first candidate cell among the multiple first candidate cells, excluding the abnormal cell, is determined as the first target cell; The second candidate cell, excluding the abnormal cell, is selected as the second target cell from among the multiple second candidate cells.

3. The energy storage control device according to claim 2, characterized in that, The status information includes the individual cell voltage; the first preset time period includes multiple first sampling moments; the candidate cell includes the first candidate cell or the second candidate cell; the target current includes the charging current or the discharging current. The equalization control module executes the target current between the energy storage module and the frequency converter module and the status information of each battery cell within a first preset time period, and obtains multiple candidate battery cells from the multiple battery cells, which are configured as follows: Based on the target current within the first preset time period and the individual voltage of each cell, multiple current differences and multiple first voltage differences are obtained. The current difference is the difference between the target currents at two adjacent first sampling times, and the first voltage difference is the difference between the maximum and minimum values ​​of the individual cell voltages within the first preset time period. When multiple consecutive current differences are less than a preset current threshold and multiple consecutive first voltage differences are less than a preset voltage threshold, a second voltage difference corresponding to each cell is obtained based on the individual cell voltage at the target first sampling time; the target first sampling time is the last first sampling time within the first preset time period, and the second voltage difference is the difference between the individual cell voltage at the target first sampling time and the minimum value among the individual cell voltages at the target first sampling time; The cell corresponding to the second voltage difference that meets the preset equalization condition is determined as the candidate cell; Wherein, when the candidate cell is the first candidate cell and the target current is the charging current, the preset equalization condition includes the second voltage difference being greater than the preset equalization threshold; when the candidate cell is the second candidate cell and the target current is the discharging current, the preset equalization condition includes the second voltage difference being less than the preset equalization threshold.

4. The energy storage control device according to claim 1, characterized in that, The device further includes: A current stabilizing module is connected to the energy storage module and configured to connect to the frequency converter module, and is also configured to stabilize the charging and discharging current between the energy storage module and the frequency converter module.

5. The energy storage control device according to claim 4, characterized in that, The current stabilization module includes: A first impedance adjustment unit, wherein a first end of the first impedance adjustment unit is connected to the energy storage module, a second end of the first impedance adjustment unit is used to connect to the frequency conversion module, and a control end of the first impedance adjustment unit is connected to the equalization control module; The equalization control module is further configured to output a current stabilization control signal to the first impedance regulation unit based on the first voltage information of the energy storage module and the second voltage information of the frequency conversion module, so as to control the equivalent impedance of the first impedance regulation unit.

6. The energy storage control device according to claim 4, characterized in that, The current stabilization module includes: The second impedance adjustment unit, the first end of which is connected to the energy storage module; The third impedance adjustment unit has a first end connected to the second end of the second impedance adjustment unit, and the second end of the third impedance adjustment unit is connected to the frequency converter module. The feedback unit has a first input terminal connected to the first terminal of the third impedance adjustment unit, a second terminal connected to the second terminal of the third impedance adjustment unit, and an output terminal connected to the control terminal of the second impedance adjustment unit. The feedback unit is used to output a feedback signal based on the voltage difference across the third impedance adjustment unit to control the equivalent impedance of the second impedance adjustment unit.

7. The energy storage control device according to claim 6, characterized in that, The control terminal of the third impedance adjustment unit is connected to the equalization control module; The equalization control module is also used to acquire temperature information of the second impedance adjustment unit and the third impedance adjustment unit, and to output a short-circuit control signal to the third impedance adjustment unit when the temperature information exceeds a preset temperature threshold, so as to short-circuit the second impedance adjustment unit and the third impedance adjustment unit.

8. The energy storage control device according to claim 1, characterized in that, Before the equalization control module determines the first priority of the first target cell and the second priority of the second target cell based on the status information of each cell, it is further configured to: During the resting phase of the energy storage module, the capacity index of each cell is obtained based on the individual cell voltage and individual cell temperature. If the capacity index of a battery cell is less than a preset first capacity threshold, the capacity difference value corresponding to each battery cell is obtained; the capacity difference value is the difference between the minimum value of the capacity index of each battery cell and the capacity index of the battery cell. Cells with a capacity difference greater than a preset second capacity threshold are identified as first target cells, and cells with a capacity difference less than or equal to the preset second capacity threshold are identified as second target cells.

9. An energy storage control system, characterized in that, It includes a load, a frequency converter connected to the load, and an energy storage control device as described in any one of claims 1-8.

10. An energy storage control method, characterized in that, The method, applied to the energy storage control device according to any one of claims 1-8, comprises: During the charging phase of the energy storage module, the first target battery cell is acquired; During the discharge phase of the energy storage module, a second target battery cell is acquired; Based on the status information of each battery cell, determine the first priority of the first target battery cell and the second priority of the second target battery cell; Based on the first priority of the first target battery cell and the second priority of the second target battery cell, a balancing process is performed on the first target battery cell and the second target battery cell. The cell capacity of the first target cell is higher than that of the second target cell.

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