Balanced charging and discharging management method for different battery pack combinations

Abstract

The invention discloses a balanced charging and discharging management method for different battery pack combinations. The balanced charging and discharging management method comprises the following steps that the battery pack combinations and a discharging part are specially designed; acquiring various parameter data of the target battery pack combination, and judging an equalization condition; determining equalization selection, and monitoring an equalization effect in real time; compared with the prior art, the system has the beneficial effects that through accurate monitoring of the MCU main control module, intelligent switching of the charging and discharging balance module and multifunctional multiplexing of the DC-DC module, the charging and discharging process can be effectively managed, unnecessary loss and risk of a battery pack combination are avoided, and the reliability of the system is improved. The combination of the DC-AC inverter output module and the straight-through interface enables the system to provide high-efficiency AC and DC power supply output, and at the same time, the USB interface provides the charging and discharging function of low-power equipment to meet the power demands of different scenes, and the modular design and diversified charging and discharging strategies enable the system to have extremely high expansibility, safety and adaptability.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a balanced charge and discharge management method for different battery group combinations. Background Art

[0002] In the traditional BMS (battery management system) design, the BMS is mainly responsible for monitoring the status of each battery cell in a single battery pack, especially the battery voltage, temperature, and charge and discharge conditions, and ensuring the consistency of each battery cell voltage through active or passive balancing functions. However, the BMS is usually limited to the management of batteries in a single battery pack and cannot effectively handle the balancing problem when multiple battery packs are used in parallel. Therefore, when multiple battery packs with BMS are connected in parallel, the voltage difference between different battery packs may cause a large current shock, which in turn causes damage to the battery or circuit.

[0003] The most common BMS systems on the market are usually limited to the management of cells in a single battery pack, with a balancing function between cells, but the balancing circuit design for multiple battery packs in parallel is relatively rare. There are some equalizers on the market for multiple battery packs in parallel, but these products are usually simple protection circuits designed to prevent excessive current, with relatively simple functions and lack of multi-purpose charge and discharge management functions.

[0004] Some advanced BMS systems also include some balancing functions, but in most cases they do not have the modular and flexible secondary balancing function of this design. Therefore, this balanced charging and discharging invention method has made significant improvements and expansions on the basis of existing products, especially in terms of safety, efficiency and functionality when multiple battery packs are connected in parallel, and has great market potential, especially in scenarios where multiple battery packs need to be used in parallel, it will have a strong competitive advantage. Summary of the invention

[0005] The object of the present invention is to provide a balanced charge and discharge management method for different battery pack combinations to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for managing balanced charge and discharge of different battery pack combinations, comprising the following contents:

[0007] S1: Special design for battery pack and discharge part;

[0008] S2: Obtain various parameter data of the target battery group and determine the balancing condition;

[0009] S3: Determine the balancing option and monitor the balancing effect in real time;

[0010] S4: Balanced charging and discharging of multiple battery packs, detection and control of voltage and current, and safety management and protection mechanisms for input and output;

[0011] S5: After completing the safety protection of the battery pack, solve the problem of the battery pack and then continue the charging and discharging work.

[0012] Preferably, S6: the battery pack is designed as a modular combination of energy storage battery boxes, each battery box can accommodate a battery capacity of about 1-10 kWh, supports the use of common energy storage battery packs such as lead-acid, lithium iron phosphate, and ternary lithium, and can flexibly provide greater output capacity and power by connecting multiple battery boxes in parallel. In order to ensure the safety and reliability when multiple battery boxes are connected in parallel, especially to avoid the generation of large currents between battery packs with different voltages, the intelligent charge and discharge management circuit is designed to use a single-chip microcomputer to monitor the voltage and current in real time, and realize voltage balancing management of the battery pack through relays and DC-DC buck-boost modules.

[0013] Preferably, S7: wherein the discharge part is designed to integrate a DC-AC inverter output module, which can convert the DC provided by the battery pack combination into a 220V sinusoidal AC output, which is suitable for various household or industrial equipment. At the same time, by reusing the aforementioned DC-DC module, the system can also provide DC outputs of different voltages to accurately meet the needs of different electrical appliances;

[0014] S8: In addition, the design also includes an independent low-power DC-DC module, which charges and discharges low-power devices such as mobile phones and tablets through a USB interface. In order to meet the needs of higher power output, the system is designed with a pass-through interface that can directly use the power of the battery pack for discharge without going through a conversion circuit, thereby providing stronger output capacity. When the battery pack is low on power, the relay will automatically disconnect the load to ensure that the battery pack will not be over-discharged, thereby extending the service life of the battery pack and improving the safety of the system.

[0015] Preferably, S9: the DC-DC module is not only used for balanced charging and discharging of the battery group combination, but can also continue to be used for photovoltaic input charging and discharging or DC power input charging and discharging after the battery groups are connected in parallel after the balancing is completed. In addition, the DC-DC module can also provide other voltage outputs higher or lower than the battery group voltage to meet different power requirements. The specific charging and discharging or output power depends on the power upper limit of the DC-DC module, which makes the system have a wider range of application scenarios and flexibility.

[0016] Preferably, S10: firstly, the BMS is used to monitor each battery cell in the battery pack to obtain key parameters such as the voltage, temperature, and remaining capacity of the battery pack. The MCU main control module is designed with multiple ADC sampling channels, which can monitor the voltage and current of each battery pack in real time;

[0017] S11: When a large voltage difference is detected between the two battery packs, the MCU determines whether the difference is beyond the acceptable range. If the voltage difference is too large, direct parallel connection may cause instantaneous large current and damage the battery or circuit. At this time, the MCU controls the charge and discharge balance module to output the battery pack to the DC-DC buck-boost module through relay switching to ensure that the high-voltage battery pack gradually charges and discharges to the low-voltage battery pack until the voltage difference and current drop below the safe value. The main control module will then control the charge and discharge balance module to switch back to the direct parallel mode.

[0018] Preferably, S12: monitor the voltage difference and temperature difference of the single battery pack, and determine whether balancing management is required through the BMS according to the monitoring result of the battery pack status.

[0019] S13: If balancing management is required, dynamic balancing or static balancing is selected according to the specific situation through BMS, and balancing is achieved by controlling the balancing circuit, including controlling the on and off of the switch, adjusting the balancing current, and other options;

[0020] S14: Dynamic balancing is selected to achieve balancing by discharging batteries with more charge in the battery pack to batteries with less charge during the charging and discharging process. This is usually achieved through a control algorithm in the BMS, which makes judgments and controls based on the status of each battery cell.

[0021] S15: If static balancing is selected, when the battery pack is fully charged, the balancing circuit is used to disperse the charge from the battery pack with higher charge to other battery packs to maintain the charge balance between the battery packs. Static balancing is generally performed when the battery pack stops charging or discharging for a long time.

[0022] Preferably, S16: when charging and discharging multiple battery packs in a balanced manner, and when there are more than two connected battery packs, the system will first start from the battery pack with the highest voltage, and gradually charge and discharge to the battery pack with the second highest voltage. After each balancing is completed, the main control module will control the charge and discharge balancing module to switch the parallel circuit, and continue to charge and discharge the battery pack with a lower voltage in a balanced manner. This process will be repeated until the voltages of all battery packs reach a balanced state and are safely connected in parallel.

[0023] S17: If balancing management is required, the BMS will select dynamic balancing or static balancing according to the specific situation, and achieve balancing by controlling the balancing circuit, which includes controlling the on and off of the switch, adjusting the balancing current, etc.

[0024] S18: During the balancing process, the BMS will continuously monitor the voltage, temperature and other parameter status changes of each battery cell in the battery pack to ensure that the balancing effect reaches the expected result;

[0025] S19: During the balanced charge and discharge process, the main control module will control the relay to disconnect the external input and output lines of the system to ensure that there will be no interference from external loads during balancing and no power will be supplied to external devices to avoid unexpected situations. After the balancing is completed, the relay will reconnect the input and output lines to ensure the normal operation of the system.

[0026] Preferably, S20: once the balance reaches the expected level, the BMS stops the balance management and waits for the next balance condition to be met before performing balance again.

[0027] Preferably, S21: in addition to utilizing the system to handle the charge and discharge balance problem, an impedance adjustment method, a voltage limiting method, and a current adjustment method may also be utilized for adjustment processing.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention uses precise monitoring of the MCU main control module, intelligent switching of the charge and discharge balance module, and multifunctional multiplexing of the DC-DC module, and the present invention can effectively manage the charge and discharge process to avoid unnecessary losses and risks. The combination of the DC-AC inverter output module and the pass-through interface enables the system to provide efficient AC and DC power outputs, while providing charging and discharging functions for low-power devices through the USB interface to meet the power requirements of different scenarios. The modular design and diversified charging and discharging strategies make the system highly scalable, safe, and adaptable. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The overall block diagram of the system of the present invention is as follows;

[0031] Figure 2 This is a schematic diagram of voltage and current detection of the present invention;

[0032] Figure 3 A schematic diagram of battery balancing according to the present invention;

[0033] Figure 4 This is a schematic diagram of input and output disconnection of the present invention;

[0034] Figure 5 The present invention is a flow chart of the method. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] See also Figures 1 to 5 The present invention provides a technical solution: a balanced charge and discharge management method for different battery pack combinations, including the following contents:

[0037] S1: Special design is adopted for battery pack combination and charging and discharging parts;

[0038] S2: Obtain various parameter data of the target battery group and determine the balancing condition;

[0039] S3: Determine the balancing option and monitor the balancing effect in real time;

[0040] S4: Balanced charging and discharging of multiple battery groups, detection and control of voltage and current, and safety management and protection mechanism for input and output;

[0041] S5: After completing the safety protection of the battery pack combination, the battery pack combination is troubleshooted and then the charging and discharging work is continued;

[0042] Among them, S6: the battery pack is designed as a modular energy storage battery box, each battery box can accommodate a battery capacity of about 1-10 kWh, and supports the use of common energy storage battery packs such as lead-acid, lithium iron phosphate, and ternary lithium. By connecting multiple battery boxes in parallel, it can flexibly provide greater output capacity and power. In order to ensure the safety and reliability of multiple battery boxes in parallel, especially to avoid the generation of large currents between battery packs with different voltages, the intelligent charge and discharge management circuit is designed as (such as Figure 1 ), using a single-chip microcomputer to monitor voltage and current in real time, and realizing battery voltage balancing management through relays and DC-DC buck-boost modules;

[0043] Among them, S7: The discharge part is designed with an integrated DC-AC inverter output module, which can convert the DC provided by the battery pack combination into a 220V sinusoidal AC output, which is suitable for various household or industrial equipment. At the same time, by reusing the aforementioned DC-DC module, the system can also provide DC outputs of different voltages to accurately meet the needs of different electrical appliances;

[0044] S8: In addition, the design also includes an independent low-power DC-DC module, which charges and discharges low-power devices such as mobile phones and tablets through the USB interface. In order to meet the demand for higher power output, the system is designed with a direct interface, which can directly use the power of the battery pack for discharge without going through a conversion circuit, thereby providing stronger output capacity. When the battery pack is low on power, the relay will automatically disconnect the load to ensure that the battery pack will not be over-discharged, extending the battery life and improving the safety of the system;

[0045] Among them, S9: The DC-DC module is not only used for balanced charging and discharging of the battery pack, but can also be used for photovoltaic input charging or DC power input charging after the battery pack is balanced and connected in parallel. In addition, the DC-DC module can also provide other voltage outputs that are higher or lower than the combined voltage of the battery pack to meet different power requirements. The specific charging and discharging or output power depends on the power upper limit of the DC-DC module, which makes the system have a wider range of application scenarios and flexibility.

[0046] Among them, S10: First, use the BMS to monitor each battery cell in the battery pack to obtain key parameters such as battery voltage, temperature, remaining capacity (SOC), etc. The MCU main control module is designed with multiple ADC sampling channels, which can monitor the voltage and current of each battery pack in real time (such as Figure 2 );

[0047] S11: When a large voltage difference is detected between the two battery packs, the MCU determines whether the difference is beyond the acceptable range. If the voltage difference is too large, direct parallel connection may cause instantaneous large current and damage the battery or circuit. At this time, the MCU controls the charge and discharge balance module to output the battery to the DC-DC buck-boost module through relay switching to ensure that the high-voltage battery pack gradually charges and discharges to the low-voltage battery pack until the voltage difference and current drop below the safe value. The main control module will then control the charge and discharge balance module to switch back to the direct parallel mode.

[0048] Among them, S12: monitoring the voltage difference and temperature difference of the single battery group, and judging whether equalization management is needed through the BMS according to the monitoring result of the battery group status;

[0049] S13: If balancing management is required, dynamic balancing or static balancing is selected according to the specific situation through BMS, and balancing is achieved by controlling the balancing circuit, including controlling the on and off of the switch, adjusting the balancing current, and other options;

[0050] S14: Dynamic balancing is selected to achieve balancing by discharging the battery pack with more charge to the battery pack with less charge during the charging and discharging process. This is usually achieved through a control algorithm in the BMS, which makes judgments and controls based on the status of each battery pack.

[0051] S15: If static balancing is selected, when the battery pack is fully charged, the balancing circuit is used to disperse the charge from the battery pack with higher charge to other battery packs to maintain the charge balance between the battery packs. Static balancing is generally performed when the battery pack stops charging or discharging for a long time.

[0052] Among them, S16: when charging and discharging multiple battery groups in a balanced manner, and when there are more than two battery groups connected, the system will first start from the battery group with the highest voltage, and gradually charge and discharge to the battery group with the second highest voltage (such as Figure 3 ), after each balancing is completed, the main control module will control the charge and discharge balancing module to switch the parallel circuit and continue to balance the charge and discharge of the battery pack with lower voltage. This process will be repeated until the voltage of all battery packs reaches a balanced state and is safely connected in parallel;

[0053] S17: If balancing management is required, the BMS will select dynamic balancing or static balancing according to the specific situation, and achieve balancing by controlling the balancing circuit, which includes controlling the on and off of the switch, adjusting the balancing current, etc.

[0054] S18: During the balancing process, the BMS will continuously monitor the voltage, temperature and other parameter status changes of the battery cells in each battery pack to ensure that the balancing effect reaches the expected result;

[0055] S19: During the balanced charge and discharge process, the main control module will control the relay to disconnect the external input and output lines of the system (such as Figure 4 ) to ensure that there will be no interference from external loads during balancing and no power will be supplied to external devices to avoid unexpected situations. After balancing is completed, the relay will reconnect the input and output lines to ensure normal operation of the system.

[0056] Among them, S20: once the balance reaches the expected level, the BMS will stop the balance management and wait for the next balance condition to be met before performing balance again.

[0057] Among them, S21: in addition to using the system to handle the balance problem of charging and discharging, the impedance adjustment method, the voltage limiting method and the current adjustment method can also be used for adjustment processing.

[0058] Specifically, when using the present invention, the battery pack is designed as a modular energy storage battery box, each battery box can accommodate a battery capacity of about 1-10 kWh, and supports the use of common energy storage battery packs such as lead-acid, lithium iron phosphate, and ternary lithium. By connecting multiple battery boxes in parallel, it is possible to flexibly provide a greater output capacity and power. In order to ensure the safety and reliability of multiple battery boxes when connected in parallel, especially to avoid the generation of large currents between battery packs with different voltages, the intelligent charge and discharge management circuit is designed as (such as Figure 1 ), a single-chip microcomputer is used to monitor the voltage and current in real time, and the voltage balancing management between battery packs is realized through relays and DC-DC buck-boost modules. The discharge part is designed with an integrated DC-AC inverter output module, which can convert the DC provided by the battery pack combination into a 220V sinusoidal AC output, which is suitable for various household or industrial equipment. At the same time, by reusing the aforementioned DC-DC modules, the system can also provide DC outputs of different voltages to accurately meet the needs of different electrical appliances. In addition, the design also includes an independent low-power DC-DC module, which charges low-power devices such as mobile phones and tablets through a USB interface. In order to meet the needs of higher power output, the system is designed with a pass-through interface, which can directly use the power of the battery pack combination for discharge without going through a conversion circuit, thereby providing a stronger output capacity. When the battery pack is charged When the battery power is insufficient, the relay will automatically disconnect the load to ensure that the battery pack will not be over-discharged, extend the battery life and improve the safety of the system. The DC-DC module is not only used for balanced charging and discharging of the battery pack, but can also be used for photovoltaic input charging or DC power input charging after the battery pack is paralleled after the balancing is completed. In addition, the DC-DC module can also provide other voltage outputs higher or lower than the combined voltage of the battery pack to meet different power requirements. The specific charging and discharging or output power depends on the power upper limit of the DC-DC module, which makes the system have a wider range of application scenarios and flexibility. First, the BMS is used to monitor each battery cell in the battery pack to obtain key parameters such as battery voltage, temperature, remaining capacity (SOC), etc. The MCU main control module is designed with multiple ADC sampling channels, which can monitor the voltage and current of each battery pack in real time (such as Figure 2), when a large voltage difference is detected between the two battery packs, the single chip will determine whether the difference is beyond the acceptable range. If the voltage difference is too large, direct parallel connection may cause instantaneous large current and damage the battery or circuit. At this time, the single chip will control the charge and discharge balance module, and output the battery to the DC-DC buck-boost module through relay switching to ensure that the high-voltage battery pack gradually charges and discharges to the low-voltage battery pack until the voltage difference and current drop below the safe value. The main control module will control the charge and discharge balance module to switch back to the direct parallel mode, monitor the voltage difference and temperature difference of the single battery pack, and determine whether balancing management is required through the BMS according to the monitoring results of the battery pack status. If balancing management is required, the BMS selects dynamic balancing or static balancing according to the specific situation, and controls the balancing circuit to To achieve balancing, there are many options, including controlling the on and off of switches, adjusting balancing current, etc. Among them, dynamic balancing means that during the charging and discharging process, the battery with more charge in the battery pack is discharged to the battery with less charge to achieve balancing. This is usually achieved through the control algorithm in the BMS, which will judge and control according to the status of each battery cell. If static balancing is selected, when the battery pack is fully charged, the balancing circuit is used to disperse the charge from the battery pack with higher charge to other battery packs to maintain the charge balance between the batteries. Static balancing is generally performed when the battery pack stops charging or discharging for a long time. When charging and discharging multiple groups of batteries, and when more than two battery packs are connected, the system will start with the battery pack with the highest voltage and gradually charge and discharge to the battery pack with the second highest voltage (such as Figure 3 ), after each balancing is completed, the main control module will control the charge and discharge balancing module to switch the parallel circuit, and continue to balance the charge and discharge of the battery pack with lower voltage. This process will be repeated until the voltage of all battery packs reaches a balanced state and is safely connected in parallel. If balancing management is required, the BMS will select dynamic balancing or static balancing according to the specific situation, and achieve balancing by controlling the balancing circuit, which includes controlling the on and off of the switch, adjusting the balancing current, etc. During the balancing process, the BMS will continuously monitor the changes in the parameters such as the voltage and temperature of each battery cell to ensure that the balancing effect is as expected. During the balancing charge and discharge process, the main control module will control the relay to disconnect the external input and output lines of the system (such as Figure 4 ) to ensure that there will be no interference from external loads during balancing, and no power will be supplied to external devices to avoid unexpected situations. After balancing is completed, the relay will reconnect the input and output lines to ensure the normal operation of the system. Once the balancing reaches the expected level, the BMS will stop balancing management and wait for the next balancing condition to be met before balancing again. In addition to using the system to handle the balancing problem of charge and discharge, it can also use impedance adjustment method, voltage limiting method and current adjustment method for adjustment.

[0059] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A balanced charge and discharge management method for different battery pack combinations, characterized in that: Includes the following: S1: Special design for battery pack combination and discharge part; S2: Obtain various parameter data of the target battery and determine the balancing condition; S3: Determine the balancing option and monitor the balancing effect in real time; S4: Balanced charging and discharging of multiple battery packs, detection and control of voltage and current, and safety management and protection mechanisms for input and output; S5: After completing the safety protection of the battery pack combination, the problem of the battery pack combination is solved, and then the charging and discharging work is continued.

2. A balanced charge and discharge management method for different battery pack combinations according to claim 1, characterized in that: It also includes S6: the battery pack combination is designed as a modular energy storage battery box. Each battery box can accommodate a battery capacity of about 1-10 kWh. It supports the use of common energy storage battery packs such as lead-acid, lithium iron phosphate, and ternary lithium. By connecting multiple battery boxes in parallel, it can flexibly provide greater output capacity and power. In order to ensure the safety and reliability when multiple battery boxes are connected in parallel, especially to avoid the generation of large currents between battery packs of different voltages, the intelligent charge and discharge management circuit is designed to use a single-chip microcomputer to monitor the voltage and current in real time, and realize battery voltage balancing management through relays and DC-DC buck-boost modules.

3. A balanced charge and discharge management method for different battery pack combinations according to claim 2, characterized in that: S7: The discharge part is designed with an integrated DC-AC inverter output module, which can convert the DC provided by the battery pack into a 220V sinusoidal AC output, suitable for various household or industrial equipment. At the same time, by reusing the aforementioned DC-DC modules, the system can also provide DC outputs of different voltages to accurately meet the needs of different electrical appliances. S8: In addition, the design also includes an independent low-power DC-DC module, which charges and discharges low-power devices such as mobile phones and tablets through the USB interface. In order to meet the needs of higher power output, the system is designed with a pass-through interface that can directly use the battery's power for discharge without going through a conversion circuit, thereby providing stronger output capacity. When the battery is low on power, the relay will automatically disconnect the load to ensure that the battery is not over-discharged, extending the battery life and improving the safety of the system.

4. A balanced charge and discharge management method for different battery pack combinations according to claim 3, characterized in that: S9: The DC-DC module is not only used for balanced charging and discharging of battery pack combinations, but can also be used for photovoltaic input charging and discharging or DC power input charging and discharging after the battery packs are connected in parallel after balancing. In addition, the DC-DC module can also provide other voltage outputs higher or lower than the battery pack voltage to meet different power requirements. The specific charging and discharging or output power depends on the power upper limit of the DC-DC module, which makes the system have a wider range of application scenarios and flexibility.

5. A balanced charge and discharge management method for different battery pack combinations according to claim 4, characterized in that In: S10: First, use the BMS to monitor each battery cell in the battery pack to obtain key parameters such as battery voltage, temperature, and remaining capacity. The MCU main control module is designed with multiple ADC sampling channels to monitor the voltage and current of each battery pack in real time; S11: When a large voltage difference is detected between the two battery packs, the MCU determines whether the difference is beyond the acceptable range. If the voltage difference is too large, direct parallel connection may cause instantaneous large current and damage the battery or circuit. At this time, the MCU controls the charge and discharge balance module to output the battery pack to the DC-DC buck-boost module through relay switching to ensure that the high-voltage battery pack gradually charges and discharges to the low-voltage battery pack until the voltage difference and current drop below the safe value. The main control module will then control the charge and discharge balance module to switch back to the direct parallel mode.

6. A balanced charge and discharge management method for different battery pack combinations according to claim 5, characterized in that In: S12: Monitor the voltage difference and temperature difference of the single battery pack, and determine whether balancing management is required through the BMS according to the monitoring results of the battery pack status; S13: If balancing management is required, dynamic balancing or static balancing is selected according to the specific situation through BMS, and balancing is achieved by controlling the balancing circuit, including controlling the on and off of the switch, adjusting the balancing current, and other options; S14: Dynamic balancing is selected to achieve balancing by discharging the battery pack with more charge to the battery pack with less charge during the charging and discharging process. This is usually achieved through a control algorithm in the BMS, which makes judgments and controls based on the status of each battery pack. S15: If static balancing is selected, when the battery pack is fully charged, the balancing circuit is used to disperse the charge from the battery pack with higher charge to other battery packs to maintain the charge balance between the battery packs. Static balancing is generally performed when the battery pack stops charging or discharging for a long time.

7. A balanced charge and discharge management method for different battery pack combinations according to claim 6, characterized in that: S16: When charging and discharging multiple battery packs in a balanced manner, and when there are more than two battery packs connected, the system will start from the battery pack with the highest voltage and gradually charge and discharge the battery pack with the second highest voltage. After each balancing is completed, the main control module will control the charge and discharge balancing module to switch the parallel circuit and continue to charge and discharge the battery pack with lower voltage in a balanced manner. This process will be repeated until the voltages of all battery packs reach a balanced state and are safely connected in parallel. S17: If balancing management is required, the BMS will select dynamic balancing or static balancing according to the specific situation, and achieve balancing by controlling the balancing circuit, which includes controlling the on and off of the switch, adjusting the balancing current, etc. S18: During the balancing process, the BMS will continuously monitor the voltage, temperature and other parameter status changes of each battery pack to ensure that the balancing effect reaches the expected result; S19: During the balanced charge and discharge process, the main control module will control the relay to disconnect the external input and output lines of the system to ensure that there will be no interference from external loads during balancing and no power will be supplied to external devices to avoid unexpected situations. After the balancing is completed, the relay will reconnect the input and output lines to ensure the normal operation of the system.

8. A balanced charge and discharge management method for different battery pack combinations according to claim 7, characterized in that: S20: Once the balance reaches the expected level, the BMS will stop the balance management and wait for the next balance condition to be met before performing the balance again.

9. A balanced charge and discharge management method for different battery pack combinations according to claim 8, characterized in that: S21: In addition to using the system to handle the balance problem of charge and discharge, it is also possible to use impedance adjustment method, voltage limiting method and current adjustment method for adjustment processing.

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