Method and device for balancing control of direct current storage battery during on-line charging and discharging process

Abstract

The application discloses a DC storage battery online charging and discharging process balancing control method and equipment, relates to the battery balancing control technical field.The method comprises the following steps: real-time monitoring of the voltage, current and temperature parameters of each single battery in the DC storage battery, generating each single monitoring data set; each single monitoring data set is sent to the master control unit to calculate the state of charge and health state of each single battery, and the unbalanced single distribution is identified; the SEPIC converter connected with the battery management system of the DC storage battery and each single battery is determined, if the SEPIC converter and the single battery are in a one-to-many adjustment relationship, the priority analysis of energy transfer is carried out according to the unbalanced single distribution and the health state, and the step-by-step balancing control is carried out. The technical problems of the prior art that the DC storage battery is not balanced and regulated in time and is unreliable in the charging and discharging process are solved, and the technical effects of improving the balancing efficiency and operation safety of the storage battery are achieved.

Description

Technical Field

[0001] This invention relates to the field of battery equalization control technology, specifically to equalization control methods and equipment for the online charging and discharging process of DC batteries. Background Technology

[0002] DC battery packs consist of numerous individual cells connected in series and parallel. During long-term charging and discharging, variations in manufacturing processes, environmental conditions, and usage can easily lead to inconsistencies in the performance of individual cells. Without effective equalization control, these differences will accumulate, causing some cells to overcharge or over-discharge, thus reducing the overall usable capacity of the battery pack, shortening battery life, and increasing safety hazards. Existing equalization control methods often suffer from slow response times, low energy transfer efficiency, and simplistic equalization strategies, making them ill-suited for complex charging and discharging conditions. Summary of the Invention

[0003] This application provides a method and equipment for equalization control during the online charging and discharging process of DC batteries, which solves the technical problems of untimely and unreliable equalization control of DC batteries during charging and discharging in the prior art.

[0004] The first aspect of this application provides a method for equalization control during the online charging and discharging process of a DC battery, the method comprising:

[0005] The voltage, current, and temperature parameters of each individual cell in a DC storage battery are monitored in real time using multi-source sensors to generate individual cell monitoring datasets. These datasets are then sent to the main control unit to calculate the state of charge and health status of each individual cell, identifying unbalanced cell distribution. The battery management system connected to the DC storage battery and the SEPIC converters connected to each individual cell are determined. If the SEPIC converters and individual cells have a one-to-many regulation relationship, priority analysis of energy transfer is performed based on the unbalanced cell distribution and health status, and phased equalization control is implemented.

[0006] A second aspect of this application provides an equalization control device for the online charging and discharging process of a DC battery, the device comprising:

[0007] Monitoring module: Utilizes multi-source sensors to monitor the voltage, current, and temperature parameters of each individual cell within the DC battery in real time, generating individual cell monitoring datasets; Identification module: Sends the individual cell monitoring datasets to the main control unit to calculate the state of charge and health status of each individual cell, identifying unbalanced cell distribution; Control module: Determines the battery management system connected to the DC battery and the SEPIC converter connected to each individual cell. If the SEPIC converter and the individual cell have a one-to-many regulation relationship, it performs priority analysis of energy transfer based on the unbalanced cell distribution and health status, and performs phased equalization control.

[0008] One or more technical solutions provided in this application have at least the following technical effects or advantages:

[0009] This system utilizes multi-source sensors to monitor the voltage, current, and temperature parameters of each individual cell within a DC storage battery in real time, generating individual cell monitoring datasets. These datasets are then sent to the main control unit to calculate the state of charge (SOC) and health status of each cell, identifying imbalanced cell distribution. The system determines the battery management system (BMS) connected to the DC storage battery and the SEPIC converters connected to each cell. If the SEPIC converters have a one-to-many regulation relationship with the cells, energy transfer priority analysis is performed based on the imbalanced cell distribution and health status, resulting in phased equalization control. This solves the technical problems of untimely and unreliable equalization control during the charging and discharging process of DC storage batteries in existing technologies, achieving improved battery equalization efficiency and operational safety. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 A schematic flowchart of the equalization control method for online charging and discharging of a DC battery provided in an embodiment of this application;

[0012] Figure 2 This is a schematic diagram of the equalization control device for the online charging and discharging process of a DC battery provided in an embodiment of this application.

[0013] Explanation of reference numerals in the attached diagram: Monitoring module 11, Identification module 12, Control module 13. Detailed Implementation

[0014] This application provides a method and equipment for equalization control during the online charging and discharging process of DC batteries, which solves the technical problem of untimely and unreliable equalization control of DC batteries during the charging and discharging process in the prior art.

[0015] 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 a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0016] It should be noted that the terms "comprising" and "having" are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or server that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or modules that are not explicitly listed or that are inherent to these processes, methods, products, or devices.

[0017] Example 1, as Figure 1 As shown, this application provides a method for equalization control during the online charging and discharging process of a DC battery, wherein the method includes:

[0018] Multi-source sensors are used to monitor the voltage, current, and temperature parameters of each individual cell in a DC battery in real time, generating individual cell monitoring datasets.

[0019] Voltage sensors, current sensors, and temperature sensors are installed on each individual cell of the DC battery pack. The voltage sensors are used to collect the voltage value across the individual cell in real time, the current sensors are used to collect the charging and discharging current value flowing through the individual cell in real time, and the temperature sensors are used to collect the temperature data of the individual cell casing or tabs in real time. Based on the above sensors, the voltage, current, and temperature parameters of each individual cell in the DC battery pack are monitored in real time, and individual cell monitoring datasets are generated.

[0020] The individual cell monitoring datasets are sent to the main control unit to calculate the state of charge and health of each individual cell and identify unbalanced cell distribution.

[0021] After the voltage, current, and temperature parameters of each individual battery cell are collected, they are sequentially transmitted to the main control unit. The main control unit filters and removes anomalies from the collected data to ensure the reliability of the monitoring results. Based on this, the main control unit uses a state of charge estimation algorithm to estimate the remaining capacity of each individual battery cell, and simultaneously assesses the health status of each individual battery cell based on the internal resistance change law and capacity decay law. The main control unit further statistically analyzes the state of charge of all individual batteries cells, calculates the overall average state of charge, and identifies individual batteries cells with a value higher than the average and a deviation exceeding a preset threshold as source individual battery cells, and individual batteries cells with a value lower than the average and a deviation exceeding the preset threshold as target individual battery cells. This generates an unbalanced distribution of individual cells, providing a basis for subsequent energy transfer.

[0022] Furthermore, the individual cell monitoring datasets are sent to the main control unit to calculate the state of charge and health of each individual cell, and to identify uneven cell distribution, including:

[0023] A state of charge (SCC) estimation sample set and a state of health (SHC) estimation sample set are collected to train the SCC estimator and the SHC estimator, respectively, and embedded in the main control unit. The monitoring datasets of each individual cell are sent to the main control unit, and the SCC and SHC of each individual cell are estimated using the SCC estimator and the SHC estimator. The mean SCC is calculated based on the SCC of each individual cell, and unbalanced cells are identified, specifically including source cell groups and target cell groups, to generate the unbalanced cell distribution.

[0024] Specifically, a large amount of sample data containing voltage, current, temperature, and capacity changes is collected and used as the state of charge (SCC) estimation sample set and the state of health (SHC) estimation sample set, respectively. The corresponding estimation algorithms are trained to form the SCC estimator and the SHC estimator, which are pre-embedded in the main control unit. The monitoring dataset of each individual cell is transmitted to the main control unit in real time. The main control unit calls the above estimators to estimate the SCC and SHC of each individual cell. The main control unit calculates the overall SCC mean based on the SCC of all individual cells and identifies individual cells with a value higher than the mean and a deviation exceeding a preset threshold as source individual cell groups, and identifies individual cells with a value lower than the mean and a deviation exceeding the preset threshold as target individual cell groups, thereby generating an unbalanced individual cell distribution.

[0025] Furthermore, the source cell battery pack includes cell units with a state of charge higher than the average state of charge and a difference greater than a preset significant judgment value; the target cell battery pack includes cell units with a state of charge lower than the average state of charge and a difference greater than a preset significant judgment value.

[0026] After obtaining the state of charge (SOC) of all individual cells, the overall SOC mean is calculated. Individual cells with an SOC higher than the mean and a difference from the mean exceeding a preset significant threshold are classified as source cell groups. The target cell group is determined as follows: under the same calculation results, individual cells with an SOC lower than the mean and a difference from the mean exceeding the preset significant threshold are classified as target cell groups.

[0027] Determine the battery management system connected to the DC battery and the SEPIC converter connected to each individual cell. If the SEPIC converter and the individual cell have a one-to-many regulation relationship, perform priority analysis of energy transfer based on the unbalanced cell distribution and health status, and perform phased equalization control.

[0028] The system identifies the battery management system (BMS) of the DC battery and the SEPIC converters connected to each individual cell. When the SEPIC converters and individual cells form a one-to-many regulation relationship, the main control unit first performs a priority analysis of the energy transfer demand between the source and target cell battery packs based on the uneven cell distribution and the health status of each cell. Specifically, the unbalanced cells are sorted according to the magnitude of their state-of-charge deviation and their health status level, generating a source cell priority sequence and a target cell priority sequence. Based on this, the main control unit controls the combination of the SEPIC converters and the input / output switch matrix to perform energy transfer operations one by one according to the priority sequence. This ensures that energy flows first between cells with significant differences and good health status. After one energy transfer is completed, the next pairing is performed, thereby achieving phased equalization control.

[0029] Furthermore, if the SEPIC converter and the individual battery have a one-to-many regulation relationship, with each individual battery connected to both the input and output terminals of the SEPIC converter, there are two independent switch matrices between the SEPIC converter and each individual battery. The input switch matrix is ​​used to connect the individual battery to the input terminal of the SEPIC converter, and the output switch matrix is ​​used to connect the individual battery to the output terminal of the SEPIC converter.

[0030] When the SEPIC converter and individual cells have a one-to-many regulation relationship, each individual cell is connected to both the input and output terminals of the SEPIC converter. Two independent switch matrices are set between the SEPIC converter and each individual cell. The input switch matrix selectively connects a specific individual cell to the input terminal of the SEPIC converter, allowing energy from that cell to be input into the converter. The output switch matrix selectively connects another individual cell to the output terminal of the SEPIC converter, transferring energy from the converter to that cell. Through the combined control of the input and output switch matrices, a flexible energy transfer channel can be established between the source and target individual cells, enabling phased equalization control of multiple individual cells. This avoids the limitations of fixed pairing methods and improves overall energy utilization efficiency.

[0031] Furthermore, any switch matrix includes multiple MOSFET switches corresponding to a single cell. By switching the MOSFET switches on and off, the SEPIC circuit is selected to control the energy transfer of the single cell.

[0032] Each switch matrix consists of multiple MOSFET switches corresponding to individual battery cells, with one MOSFET switch for each individual cell. By controlling the on / off state of the MOSFET switches, a specific battery cell can be flexibly selected for connection to the input or output of the SEPIC converter. When the MOSFET switch of a particular battery cell is in the on state, that battery cell can establish an energy transfer path with the SEPIC circuit, thereby enabling the source battery cell to input energy to the SEPIC converter, or the SEPIC converter to output energy to the target battery cell. Through combined control of the input and output MOSFET switches, multiple energy transfer paths can be established between multiple battery cells, achieving phased and controllable equalization adjustment, ensuring the flexibility and efficiency of the energy transfer process.

[0033] Furthermore, based on the uneven distribution of individual cells and their health status, priority analysis of energy transfer is conducted, and phased equilibrium control is implemented, including:

[0034] In both the source and target battery packs, the degree of imbalance is calculated and assigned to the corresponding individual cells. Based on the imbalance labels, individual cells with the same degree of imbalance are identified, and their imbalance is adjusted according to their health status. The source and target battery packs are then prioritized based on the adjusted imbalance, generating a source battery priority sequence and a target battery priority sequence. Energy transfer is paired based on these priority sequences, and energy transfer control is performed in stages via a SEPIC converter, using an input and output switch matrix.

[0035] First, the difference between the state of charge (SOC) of each individual cell in the source and target battery packs and the overall SOC mean is calculated. This difference is used as an indicator of the degree of imbalance and stored in the corresponding cell's labeling information. During this process, multiple imbalance level ranges can be set, such as mild, moderate, and severe, to classify batteries with different deviation ranges. Then, for cells with the same degree of imbalance, their health status is corrected: if a cell's health status is below a set threshold (i.e., significant capacity decay or a marked increase in internal resistance), its energy transfer priority is reduced during sorting to avoid overcharging and discharging of the degraded cell; if its health status is good, its original imbalance level label is maintained. Based on the corrected imbalance level, the main control unit performs a comprehensive priority sorting of the source and target battery packs, generating a source cell priority sequence and a target cell priority sequence, where the sequence order reflects the execution order of the individual cells in the energy transfer process. Based on this, the main control unit performs energy transfer pairing according to a priority sequence, pairing the highest-priority source cell with the highest-priority target cell to form a balanced battery pair. The main control unit controls the MOSFET switch of the corresponding source cell in the input switch matrix to turn on, and simultaneously controls the MOSFET switch of the corresponding target cell in the output switch matrix to turn on, thus establishing an energy transfer path; then, an energy transfer is performed between the source and target cells via the SEPIC converter. After one energy transfer is completed, the main control unit turns off the corresponding MOSFET switch, releases the SEPIC converter, and then selects the next pair of source and target cells according to the balanced battery pair sequence, repeating the above energy transfer process.

[0036] Furthermore, energy transfer is paired based on the source cell priority sequence and the target cell priority sequence. Combined with the input and output switching matrices, energy transfer control is performed in stages via a SEPIC converter, including:

[0037] Using the mean state of charge as the balancing target, individual cells in the source cell priority sequence and the target cell priority sequence are paired according to priority to determine the balancing cell pair sequence, where each cell pair is marked with energy transfer parameters. The source cell and the target cell in the first cell pair in the balancing cell pair sequence are extracted, the MOSFET switch corresponding to the source cell in the input switch matrix is ​​closed, and the MOSFET switch corresponding to the target cell in the output switch matrix is ​​closed. Energy transfer control is performed according to the corresponding first energy transfer parameters. After the first control is completed, the energy transfer control of the cell pair is performed again according to the balancing cell pair sequence.

[0038] Specifically, using the average state of charge (SOC) as the balancing target, batteries in the source cell priority sequence are paired one-to-one with batteries in the target cell priority sequence according to their priority order, forming a balanced battery pair sequence. Each balanced battery pair is assigned an energy transfer parameter, which is determined by the SOC difference and health status of the source and target cells, and is used to indicate the amount of energy or transfer time required between the battery pairs.

[0039] During execution, the main control unit first extracts the first battery pair from the equalization battery pair sequence, controls the MOSFET switch corresponding to the source battery in the input switch matrix to turn on, connecting the source battery to the input terminal of the SEPIC converter. Simultaneously, it controls the MOSFET switch corresponding to the target battery in the output switch matrix to turn on, connecting the target battery to the output terminal of the SEPIC converter. Then, based on the energy transfer parameters marked on the first battery pair, it drives the SEPIC converter to operate, realizing energy transfer from the source battery to the target battery, until the energy transfer reaches the set transfer amount or transfer time. After the first energy transfer is completed, the main control unit turns off the relevant MOSFET switch, disconnecting the energy transfer path of the battery pair, and automatically extracts the next battery pair from the equalization battery pair sequence, repeating the above switching control and energy transfer process.

[0040] Furthermore, if the SEPIC converter and the individual battery cells have a one-to-one regulation relationship, the energy transfer is synchronously controlled based on the uneven distribution of individual cells.

[0041] When the SEPIC converter and individual battery cells have a one-to-one regulation relationship, each individual battery cell is connected to an independent SEPIC converter. The main control unit can directly issue control commands to all individual batteries requiring energy transfer based on the uneven distribution of individual cells. Specifically, after identifying the source and target battery cell packs, the main control unit determines the corresponding energy transfer parameters based on the degree of imbalance and health status, and simultaneously drives the SEPIC converter corresponding to the source battery cell to perform energy output control and the SEPIC converter corresponding to the target battery cell to perform energy input control.

[0042] Furthermore, if the SEPIC converter and the individual battery have a one-to-one regulation relationship, each individual battery is connected to the input terminal of its corresponding SEPIC converter, and the output terminals of each SEPIC converter are connected in parallel to a common global energy bus.

[0043] When the SEPIC converter and individual battery cells have a one-to-one regulation relationship, each individual battery cell is connected to the input of an independently configured SEPIC converter through its positive and negative terminals. This allows each individual battery cell to independently supply energy to or receive energy from its corresponding SEPIC converter. The outputs of all the SEPIC converters are connected in parallel to form a common global energy bus. This energy bus serves as a unified channel for energy exchange, enabling centralized energy transfer and distribution between different individual batteries. With this structure, when a battery cell is identified as a source battery, its corresponding SEPIC converter can output energy to the global energy bus, while when another battery cell is identified as a target battery, its corresponding SEPIC converter can obtain energy from the global energy bus.

[0044] In summary, the embodiments of this application have at least the following technical effects:

[0045] This system utilizes multi-source sensors to monitor the voltage, current, and temperature parameters of each individual cell within a DC storage battery in real time, generating individual cell monitoring datasets. These datasets are then sent to the main control unit to calculate the state of charge (SOC) and health status of each cell, identifying imbalanced cell distribution. The system determines the battery management system (BMS) connected to the DC storage battery and the SEPIC converters connected to each cell. If the SEPIC converters have a one-to-many regulation relationship with the cells, energy transfer priority analysis is performed based on the imbalanced cell distribution and health status, resulting in phased equalization control. This solves the technical problems of untimely and unreliable equalization control during the charging and discharging process of DC storage batteries in existing technologies, achieving improved battery equalization efficiency and operational safety.

[0046] Example 2, based on the same inventive concept as the equalization control method in the online charging and discharging process of the DC battery in the previous examples, such as... Figure 2 As shown, this application provides an equalization control device for the online charging and discharging process of a DC battery, wherein the device includes:

[0047] Monitoring module 11: Utilizes multi-source sensors to monitor the voltage, current, and temperature parameters of each individual cell in the DC battery in real time, generating individual cell monitoring datasets; Identification module 12: Sends the individual cell monitoring datasets to the main control unit to calculate the state of charge and health status of each individual cell, identifying unbalanced cell distribution; Control module 13: Determines the battery management system connected to the DC battery and the SEPIC converter connected to each individual cell. If the SEPIC converter and the individual cell have a one-to-many regulation relationship, it performs priority analysis of energy transfer based on the unbalanced cell distribution and health status, and performs phased equalization control.

[0048] Furthermore, the control module 13 is used to perform the following methods:

[0049] If the SEPIC converter and the individual battery have a one-to-many regulation relationship, each individual battery is connected to the input and output terminals of the SEPIC converter. There are two independent switch matrices between the SEPIC converter and each individual battery. The input switch matrix is ​​used to connect the individual battery to the input terminal of the SEPIC converter, and the output switch matrix is ​​used to connect the individual battery to the output terminal of the SEPIC converter.

[0050] Furthermore, the control module 13 is used to perform the following methods:

[0051] Any switch matrix includes multiple MOSFET switches corresponding to a single cell. By switching the MOSFET switches on and off, the SEPIC circuit controls the energy transfer of the single cell.

[0052] Furthermore, the identification module 12 is used to perform the following method:

[0053] A state of charge (SCC) estimation sample set and a state of health (SHC) estimation sample set are collected to train the SCC estimator and the SHC estimator, respectively, and embedded in the main control unit. The monitoring datasets of each individual cell are sent to the main control unit, and the SCC and SHC of each individual cell are estimated using the SCC estimator and the SHC estimator. The mean SCC is calculated based on the SCC of each individual cell, and unbalanced cells are identified, specifically including source cell groups and target cell groups, to generate the unbalanced cell distribution.

[0054] Furthermore, the identification module 12 is used to perform the following method:

[0055] The source cell battery pack includes cell units with a state of charge (SOC) higher than the average SOC, and the difference is greater than a preset significant judgment value; the target cell battery pack includes cell units with a SOC lower than the average SOC, and the difference is greater than a preset significant judgment value.

[0056] Furthermore, the control module 13 is used to perform the following methods:

[0057] In both the source and target battery packs, the degree of imbalance is calculated and assigned to the corresponding individual cells. Based on the imbalance labels, individual cells with the same degree of imbalance are identified, and their imbalance is adjusted according to their health status. The source and target battery packs are then prioritized based on the adjusted imbalance, generating a source battery priority sequence and a target battery priority sequence. Energy transfer is paired based on these priority sequences, and energy transfer control is performed in stages via a SEPIC converter, using an input and output switch matrix.

[0058] Furthermore, the control module 13 is used to perform the following methods:

[0059] Using the mean state of charge as the balancing target, individual cells in the source cell priority sequence and the target cell priority sequence are paired according to priority to determine the balancing cell pair sequence, where each cell pair is marked with energy transfer parameters. The source cell and the target cell in the first cell pair in the balancing cell pair sequence are extracted, the MOSFET switch corresponding to the source cell in the input switch matrix is ​​closed, and the MOSFET switch corresponding to the target cell in the output switch matrix is ​​closed. Energy transfer control is performed according to the corresponding first energy transfer parameters. After the first control is completed, the energy transfer control of the cell pair is performed again according to the balancing cell pair sequence.

[0060] Furthermore, the control module 13 is used to perform the following methods:

[0061] If the SEPIC converter and the individual battery cells have a one-to-one regulation relationship, the energy transfer is synchronously controlled according to the uneven distribution of individual cells.

[0062] Furthermore, the optimization module 13 is used to perform the following method:

[0063] If the SEPIC converter and the individual battery have a one-to-one regulation relationship, each individual battery is connected to the input terminal of its corresponding SEPIC converter, and the output terminals of each SEPIC converter are connected in parallel to a common global energy bus.

[0064] It should be noted that the order of the embodiments described above is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, the above description focuses on specific embodiments of this specification. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired results. In some implementations, multitasking and parallel processing are possible or may be advantageous.

[0065] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

[0066] This specification and accompanying drawings are merely illustrative examples of this application and are intended to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Therefore, if such modifications and modifications fall within the scope of this application and its equivalents, this application intends to include such modifications and modifications.

Claims

1. A method for equalization control during the online charging and discharging process of a DC battery, characterized in that, The method includes: The voltage, current and temperature parameters of each cell in a DC battery are monitored in real time using multi-source sensors, and a monitoring dataset for each cell is generated. The individual cell monitoring datasets are sent to the main control unit to calculate the state of charge and health of each individual cell and identify unbalanced cell distribution. Determine the battery management system connected to the DC battery and the SEPIC converter connected to each individual cell. If the SEPIC converter and the individual cell have a one-to-many regulation relationship, perform priority analysis of energy transfer based on the unbalanced cell distribution and health status, and perform phased equalization control. This includes sending the individual cell monitoring datasets to the main control unit to calculate the state of charge and health status of each individual cell, and identifying uneven cell distributions, including: The state of charge estimation sample set and the state of health estimation sample set are collected to train the state of charge estimator and the state of health estimator respectively, and then embedded into the main control unit; The individual cell monitoring datasets are sent to the main control unit, and the state of charge and health of each individual cell are estimated by the state of charge estimator and the health state estimator. The average state of charge (SOC) is calculated based on the SOC of each individual cell, and unbalanced cells are identified, including source cell groups and target cell groups, to generate the unbalanced cell distribution. Among these measures, priority analysis of energy transfer based on the uneven distribution of individual cells and their health status is used to implement phased equilibrium control, including: The degree of imbalance is calculated for both the source and target cell packs and then marked to the corresponding cell. Based on the imbalance degree marker, identify individual cells with the same imbalance degree, adjust the imbalance degree in combination with the health status, and sort the source cell battery pack and the target cell battery pack according to the adjusted imbalance degree to generate the source cell battery priority sequence and the target cell battery priority sequence. Energy transfer is paired based on the priority sequence of the source cell and the priority sequence of the target cell, and energy transfer is controlled in stages by the SEPIC converter in combination with the input switch matrix and the output switch matrix.

2. The equalization control method for the online charging and discharging process of a DC battery as described in claim 1, characterized in that, If the SEPIC converter and the individual battery have a one-to-many regulation relationship, each individual battery is connected to the input and output terminals of the SEPIC converter. There are two independent switch matrices between the SEPIC converter and each individual battery. The input switch matrix is ​​used to connect the individual battery to the input terminal of the SEPIC converter, and the output switch matrix is ​​used to connect the individual battery to the output terminal of the SEPIC converter.

3. The equalization control method for the online charging and discharging process of a DC battery as described in claim 2, characterized in that, Any switch matrix includes multiple MOSFET switches corresponding to a single cell. By switching the MOSFET switches on and off, the SEPIC circuit controls the energy transfer of the single cell.

4. The equalization control method for the online charging and discharging process of a DC battery as described in claim 1, characterized in that, The source cell battery pack includes cell units with a state of charge (SOC) higher than the average SOC, and the difference is greater than a preset significant judgment value; the target cell battery pack includes cell units with a SOC lower than the average SOC, and the difference is greater than a preset significant judgment value.

5. The equalization control method for the online charging and discharging process of a DC battery as described in claim 1, characterized in that, Energy transfer is paired based on the priority sequences of source and target cells. Combined with input and output switching matrices, energy transfer is controlled in stages via a SEPIC converter, including: Using the mean state of charge as the balancing target, individual cells in the source cell priority sequence and the target cell priority sequence are paired according to priority to determine the balancing cell pair sequence, where each cell pair is marked with energy transfer parameters; Extract the source cell and target cell from the first cell pair in the balanced cell pair sequence, close the MOSFET switch corresponding to the source cell in the input switch matrix, close the MOSFET switch corresponding to the target cell in the output switch matrix, and perform energy transfer control according to the corresponding first energy transfer parameters; After the first control is completed, the energy transfer control of the battery pair continues according to the balanced battery pair sequence.

6. The equalization control method for the online charging and discharging process of a DC battery as described in claim 1, characterized in that, If the SEPIC converter and the individual battery cells have a one-to-one regulation relationship, the energy transfer is synchronously controlled according to the uneven distribution of individual cells.

7. The equalization control method for the online charging and discharging process of a DC battery as described in claim 6, characterized in that, If the SEPIC converter and the individual battery have a one-to-one regulation relationship, each individual battery is connected to the input terminal of its corresponding SEPIC converter, and the output terminals of each SEPIC converter are connected in parallel to a common global energy bus.

8. A balancing control device for the online charging and discharging process of a DC battery, characterized in that, For implementing the equalization control method during the online charging and discharging process of a DC battery according to any one of claims 1-7, the device comprises: Monitoring module: Utilizes multi-source sensors to monitor the voltage, current, and temperature parameters of each individual cell in the DC battery in real time, generating monitoring datasets for each individual cell; Identification module: Sends the monitoring datasets of each individual cell to the main control unit to calculate the state of charge and health of each individual cell, and identifies unbalanced cell distribution; Control module: Determines the battery management system connected to the DC battery and the SEPIC converter connected to each individual cell. If the SEPIC converter and the individual cell have a one-to-many regulation relationship, it performs priority analysis of energy transfer based on the unbalanced distribution of cells and their health status, and performs equalization control in stages.

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