Lithium ion battery system for in-situ replacement of armored vehicle parallel lead acid batteries

Abstract

The application relates to the technical field of battery management, and discloses a lithium ion battery system for in-situ replacement of armored vehicle parallel lead-acid storage batteries, which comprises a first lithium ion battery module, a second lithium ion battery module, a master control management unit, a slave control management unit and a system total switch contactor. The two lithium ion battery modules are connected in parallel, and the master control management unit and the slave control management unit are integrated in the two lithium ion battery modules respectively; the slave control management unit reports voltage, current and temperature data to the master control management unit through an isolation communication bus; the master control management unit controls the on-off of the system total switch contactor; the lithium ion battery module is identical with the original lead-acid storage battery in appearance size, installation mode and electrode pile head, and in-situ replacement is realized. The application realizes unified management and protection of the two battery modules and realizes in-situ replacement of the lithium ion battery system under the premise that the lithium ion battery system is completely identical with the original lead-acid storage battery in external size, installation mode and electrode pile head.

Description

Technical Field

[0001] This invention relates to the field of battery management technology, and in particular to a lithium-ion battery system for in-situ replacement of parallel lead-acid batteries in armored vehicles. Background Technology

[0002] Lead-acid batteries have long been the standard onboard power source for armored vehicles, supplied in parallel pairs to power the vehicle's starting system, control system, and onboard equipment. While lead-acid batteries are technologically mature and inexpensive, their inherent drawbacks—low energy density, heavy weight, poor low-temperature performance, and short cycle life—are becoming increasingly apparent in the actual service environment of armored vehicles, making them unsuitable for the high power density, wide temperature range adaptability, and long lifespan requirements of modern armored vehicles. Lithium-ion batteries, with their high energy density, long cycle life, and excellent charge-discharge characteristics, are considered the ideal solution to replace lead-acid batteries in armored vehicles.

[0003] Current armored vehicle power upgrade solutions typically involve replacing the entire vehicle's power system, meaning that the vehicle's electrical wiring, battery compartment structure, and charging system are modified simultaneously while the battery is being replaced. However, this approach requires extensive disassembly and reassembly of the vehicle's electrical system, resulting in a long modification cycle, high construction complexity, and poor compatibility between the modified system and the original vehicle's electrical architecture, posing a significant modification risk. Currently, there is no in-situ replacement solution that can completely integrate the lithium-ion battery system with the original parallel lead-acid battery in terms of installation location, method, and electrical interface without altering any of the vehicle's electrical wiring or structure, while simultaneously achieving status monitoring, coordinated control, and energy balancing between the two battery modules. Summary of the Invention

[0004] In view of this, the present invention proposes a lithium-ion battery system for in-situ replacement of parallel lead-acid batteries in armored vehicles. This solves the problem in the prior art that when upgrading and replacing parallel lead-acid batteries in armored vehicles with lithium-ion batteries, large-scale modifications to the vehicle's electrical wiring and installation structure are required, resulting in long modification cycles, poor compatibility, and the inability to achieve in-situ replacement of two parallel battery modules for coordinated status monitoring and control without altering any electrical interfaces or mechanical structures of the vehicle.

[0005] The technical solution of this invention is implemented as follows: This invention provides a lithium-ion battery system for in-situ replacement of parallel lead-acid batteries in armored vehicles. The system includes a first lithium-ion battery module, a second lithium-ion battery module, a main control management unit, a slave control management unit, and a system master switch contactor. The first lithium-ion battery module and the second lithium-ion battery module are connected in parallel. The main control management unit is integrated into the first lithium-ion battery module, and the slave control management unit is integrated into the second lithium-ion battery module. The slave control management unit is connected to the master control management unit through an isolated communication bus, and reports the voltage, current and temperature data of the second lithium-ion battery module to the master control management unit; The system master switch contactor is connected in series in the charging and discharging circuits of the first lithium-ion battery module and the second lithium-ion battery module. The control terminal of the system master switch contactor is connected to the main control management unit. The main control management unit controls the on / off state of the system master switch contactor according to the voltage, current and temperature data reported by the slave control management unit. Each lithium-ion battery module has the same external dimensions, installation method, and electrode terminals as the lead-acid battery it is replacing.

[0006] In some embodiments, the system further includes a bidirectional active balancing circuit and an independent balancing bus. The bidirectional active balancing circuit is respectively disposed in the first lithium-ion battery module and the second lithium-ion battery module, and the independent balancing bus is used to connect the first lithium-ion battery module and the second lithium-ion battery module. The data reported by the slave control management unit to the master control management unit also includes the state of charge (SOC) data of the second lithium-ion battery module. The master control management unit compares the SOC data of the second lithium-ion battery module with the SOC data of the first lithium-ion battery module. When there is a difference, the master control management unit controls the bidirectional active balancing circuit to perform energy scheduling between the first and second lithium-ion battery modules through the independent balancing bus. The master control management unit prioritizes energy scheduling between the first and second lithium-ion battery modules and then performs energy scheduling between the cells within each lithium-ion battery module.

[0007] In some embodiments, the main control management unit also collects charging and discharging current data of the first lithium-ion battery module and the second lithium-ion battery module, and calculates the charging and discharging current mutation amount based on the charging and discharging current data. The main control management unit calculates the state of charge difference between the state of charge data of the first lithium-ion battery module and the state of charge data of the second lithium-ion battery module, compares the state of charge difference with a preset difference threshold, and compares the charge and discharge current mutation with a preset disturbance threshold. When the state of charge difference exceeds the preset difference threshold and the sudden change in charge / discharge current does not exceed the preset disturbance threshold, the main control management unit sends an equalization trigger command to the bidirectional active equalization circuit through the independent equalization bus; when the sudden change in charge / discharge current exceeds the preset disturbance threshold, the main control management unit does not send an equalization trigger command to the bidirectional active equalization circuit.

[0008] In some embodiments, after the equalization trigger command is issued, the main control management unit continuously collects the charging and discharging current data of the first lithium-ion battery module and the second lithium-ion battery module and updates the charging and discharging current mutation amount. When the sudden change in the charging and discharging current exceeds the preset disturbance threshold, the main control management unit sends a pause command to the bidirectional active balancing circuit through the independent balancing bus. After issuing the pause command, the main control management unit continuously monitors the charge and discharge current fluctuation. When the charge and discharge current fluctuation drops below the preset disturbance threshold and lasts for more than the preset stable duration, the main control management unit re-collects the state of charge data of the first lithium-ion battery module and the state of charge data of the second lithium-ion battery module and recalculates the state of charge difference. When the recalculated state of charge difference exceeds the preset difference threshold, the main control management unit sends a recovery equalization command to the bidirectional active equalization circuit through the independent equalization bus. When the recalculated state of charge difference does not exceed the preset difference threshold, the main control management unit ends the current balance scheduling.

[0009] In some embodiments, the system further includes a first DC-DC conversion circuit and a second DC-DC conversion circuit, wherein the first DC-DC conversion circuit is integrated within a first lithium-ion battery module and the second DC-DC conversion circuit is integrated within a second lithium-ion battery module. The input terminal of the first DC-DC converter is connected to the vehicle's main power supply, and the output terminal of the first DC-DC converter is connected to the main control management unit to provide operating power to the main control management unit. The input terminal of the second DC-DC converter is connected to the vehicle's main power supply, and the output terminal of the second DC-DC converter is connected to the slave control management unit to provide operating power to the slave control management unit.

[0010] In some embodiments, a first reverse polarity protection diode is connected in series at the input terminal of the first DC-DC converter circuit, and a second reverse polarity protection diode is connected in series at the input terminal of the second DC-DC converter circuit. The system also includes a main power switch, which is connected in series between the vehicle's main power supply and the control coil of the system's main switch contactor. When the main power switch is turned on, the vehicle's main power supply supplies power to the control coil of the system's main switch contactor through the main power switch.

[0011] In some embodiments, the system further includes a first heating device and a second heating device, the first heating device being disposed on the surface of a first lithium-ion battery module and the second heating device being disposed on the surface of a second lithium-ion battery module; The output of the first DC-DC converter is also connected to the first heating device to provide power to the first heating device. The output of the second DC-DC converter is also connected to the second heating device to provide power to the second heating device. The control terminal of the master control management unit is connected to the first heating device, and the control terminal of the slave control management unit is connected to the second heating device.

[0012] In some embodiments, the master control management unit collects temperature data of the first lithium-ion battery module, and the slave control management unit collects temperature data of the second lithium-ion battery module; when the temperature data is lower than a first preset threshold and the vehicle generator is in operation, the corresponding management unit activates the corresponding heating device; when the temperature data is lower than a second preset threshold, the corresponding management unit controls the corresponding heating device to enter an emergency heating mode; when the temperature data rises to a third preset threshold, the corresponding management unit shuts down the corresponding heating device; wherein the second preset threshold is lower than the first preset threshold, and the third preset threshold is higher than the first preset threshold.

[0013] In some embodiments, the slave control management unit also collects the cell voltage, module current and temperature in the second lithium-ion battery module, and independently performs overcharge protection, over-discharge protection, overcurrent protection and short circuit protection on the charging and discharging circuit of the second lithium-ion battery module based on the cell voltage, module current and temperature.

[0014] In some embodiments, both the first lithium-ion battery module and the second lithium-ion battery module are composed of multiple lithium iron phosphate cells, which are connected in series in groups of eight and in parallel in multiple groups to form the first lithium-ion battery module and the second lithium-ion battery module.

[0015] The lithium-ion battery system of the present invention for in-situ replacement of parallel lead-acid batteries in armored vehicles has the following advantages over the prior art: (1) This application establishes an information transmission channel between two parallel lithium-ion battery modules by inputting the voltage, current and temperature data of the second lithium-ion battery module collected by the slave control management unit to the master control management unit; then, the reported data and the status information of the first lithium-ion battery module are input into the control logic of the master control management unit, and the electrical isolation characteristics of the isolated communication bus are used to model the coordination control relationship between the modules, extract key status parameters to complete the on / off control of the system master switch contactor, generate a unified charging and discharging management strategy, thereby capturing the status differences and coordination needs between the parallel lithium-ion battery modules through the master-slave distributed control architecture, realizing the unified management and protection of the two battery modules, and realizing the in-situ replacement of the lithium-ion battery system while maintaining the same external size, installation method and electrode terminals as the original lead-acid battery; (2) This application realizes energy scheduling between the first lithium-ion battery module and the second lithium-ion battery module through the coordinated cooperation of bidirectional active balancing circuit and independent balancing bus; by introducing a charging and discharging current change detection mechanism, a joint trigger judgment condition of charge state difference and current disturbance state is established, which effectively avoids the erroneous balancing caused by voltage drop under the transient high current condition of armored vehicle; through dynamic disturbance perception, automatic pause and intelligent recovery strategy in the balancing process, the accuracy and reliability of balancing scheduling between modules in complex electromagnetic environment are ensured, and high-precision and adaptive energy balancing management of parallel lithium-ion battery system of armored vehicle is realized. (3) This application generates a stable power supply for the management unit by inputting the vehicle host power supply into the first DC-DC conversion circuit and the second DC-DC conversion circuit; then, the temperature data collected by the management unit and the preset three-level temperature threshold are input into the temperature control logic. The three-stage temperature control strategy is used to model the heating requirements of the lithium-ion battery module in the low-temperature environment of the armored vehicle, extract the temperature state characteristics to complete the start-up, emergency heating and shutdown control of the heating device, and generate a hierarchical heating management strategy. Thus, the individual temperature changes and heating requirements of each lithium-ion battery module are captured through independent DC-DC conversion circuits and distributed heating devices, realizing reliable power supply and precise control of the low-temperature protection function of the lithium-ion battery module from the vehicle host power supply, and realizing adaptive temperature management and safety protection of the lithium-ion battery system in the wide temperature range working environment of the armored vehicle. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the 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.

[0017] Figure 1This is a structural diagram of a lithium-ion battery system for in-situ replacement of parallel lead-acid batteries in armored vehicles according to the present invention. Figure 2 This is a block diagram illustrating the principle of a BMS according to an embodiment of the present invention. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] Please see Figure 1 The present invention provides a lithium-ion battery system for in-situ replacement of parallel lead-acid batteries in armored vehicles. The system includes a first lithium-ion battery module, a second lithium-ion battery module, a master control management unit, a slave control management unit, and a system master switch contactor.

[0020] In this embodiment, the first and second lithium-ion battery modules are connected in parallel, achieving the same electrical topology as the original armored vehicle's lead-acid battery. The main control management unit is integrated inside the first lithium-ion battery module, avoiding the complexity of external wiring; correspondingly, the slave control management unit is integrated inside the second lithium-ion battery module, forming a distributed control architecture. This integrated design ensures complete independence of each module in terms of physical size and installation interface.

[0021] The slave control unit establishes a data transmission channel with the master control unit via an isolated communication bus. The isolated communication bus employs an electrical isolation design, effectively preventing electrical interference between the two modules while ensuring communication reliability. The slave control unit monitors key operating parameters of the second lithium-ion battery module in real time, including voltage, current, and temperature data, and periodically reports these parameters to the master control unit using a preset communication protocol.

[0022] The system master switch contactor, serving as the main control switch for the entire system, is connected in series in the charging and discharging main circuit of the first and second lithium-ion battery modules. The control terminal of the system master switch contactor is directly connected to the main control management unit. Based on the voltage, current, and temperature data reported by the slave control management unit, and combined with the local monitoring data of the first lithium-ion battery module, the main control management unit executes comprehensive safety judgment logic to achieve intelligent control of the on / off state of the system master switch contactor.

[0023] Specifically, the external dimensions, installation method, and terminal terminals of each lithium-ion battery module are strictly designed according to the specifications of the lead-acid battery being replaced, ensuring a perfect match with the original vehicle's battery compartment, mounting bracket, and cable connectors. The external dimensions precisely replicate the length, width, and height of the original lead-acid battery. The installation method retains the bottom mounting holes and side snap-fit ​​structure. The terminal terminals use the same material, size, and thread specifications as the original lead-acid battery.

[0024] This embodiment constructs a lithium-ion battery system with distributed monitoring, centralized management, and in-situ compatibility. Without altering any electrical wiring or mechanical structure of the armored vehicle, the system seamlessly replaces the original parallel lead-acid battery. Simultaneously, through a master-slave control architecture, it provides precise status monitoring, intelligent protection, and coordinated management functions that traditional lead-acid batteries cannot offer. The lithium-ion battery system not only significantly improves the energy density and reliability of the armored vehicle's power system but also provides a complete data support foundation for battery maintenance and performance optimization.

[0025] In some embodiments, the system further includes a bidirectional active balancing circuit and an independent balancing bus. The bidirectional active balancing circuit is respectively disposed in the first lithium-ion battery module and the second lithium-ion battery module. The independent balancing bus is used to connect the first lithium-ion battery module and the second lithium-ion battery module. The data reported by the slave control management unit to the master control management unit also includes the state of charge (SOC) data of the second lithium-ion battery module. The master control management unit compares the SOC data of the second lithium-ion battery module with the SOC data of the first lithium-ion battery module. When there is a difference between the two, the master control management unit controls the bidirectional active balancing circuit to perform energy scheduling between the first lithium-ion battery module and the second lithium-ion battery module through the independent balancing bus. The master control management unit prioritizes energy scheduling between the first lithium-ion battery module and the second lithium-ion battery module, and then performs energy scheduling between the cells within each lithium-ion battery module.

[0026] In practical implementation, the bidirectional active balancing circuit adopts a transformer-based inductive balancing topology, featuring bidirectional energy transfer capability and high conversion efficiency (>95%). The bidirectional active balancing circuit within the first lithium-ion battery module is located at the bottom of the battery pack, achieving miniaturization through an integrated circuit board. The bidirectional active balancing circuit within the second lithium-ion battery module uses the same design architecture as the first module, ensuring system consistency and reliability.

[0027] It is understandable that the independent equalization bus uses differential signal transmission, providing electrical isolation and anti-interference capabilities, with a transmission rate of 1Mbps, enabling real-time transmission of equalization control commands and status feedback information. The equalization bus uses a 4-core shielded cable to connect the two battery modules, with a cable length of 1.5 meters, meeting the wiring requirements inside armored vehicles.

[0028] The state of charge (SOC) data reported by the slave control unit to the master control unit is calculated using the ampere-hour integration method combined with the open-circuit voltage method, achieving an accuracy of ±2%. After receiving the SOC data from the second lithium-ion battery module, the master control unit compares it with the SOC data from the local first lithium-ion battery module in real time, with a comparison period of 1 second, to ensure timely detection of SOC differences.

[0029] In the application, when the SOC difference between two battery modules is detected to be ≥5%, the main control management unit initiates the inter-module energy scheduling function. The energy scheduling process adopts a hierarchical control strategy: priority is given to energy scheduling between the first and second lithium-ion battery modules to reduce the SOC difference between the two modules to within 3%; subsequently, fine energy scheduling is performed between the eight series-connected cells within each lithium-ion battery module to ensure that the voltage difference between individual cells is ≤50mV.

[0030] For example, the formula for calculating the hierarchical bidirectional active equalization power allocation in energy scheduling is: ; in, The power to be allocated by the bidirectional active equalization circuit; To achieve the equilibrium efficiency coefficient; To effectively balance capacity; This represents the difference in the state of charge between the two modules. and These are the voltages of the two modules, respectively. The expected equilibrium time; This is a nonlinear adjustment factor. The hierarchical bidirectional active equalization power allocation calculation formula uses an exponential function term. To achieve nonlinear power regulation, when When the difference is small, the equalization power gradually decreases to avoid over-equalization; when The rapid response when the difference is large reflects an intelligent hierarchical balancing strategy.

[0031] In this embodiment, by introducing a bidirectional active balancing circuit and a hierarchical balancing control strategy, safe parallel operation between battery modules in different SOC states is achieved. This design not only improves the system's energy utilization efficiency but also extends the battery system's lifespan, providing a more stable and reliable power supply for armored vehicles.

[0032] In some embodiments, the main control management unit further collects charging and discharging current data of the first lithium-ion battery module and the second lithium-ion battery module, and calculates the charge and discharge current mutation amount based on the charging and discharging current data; the main control management unit calculates the state of charge difference between the state of charge data of the first lithium-ion battery module and the state of charge data of the second lithium-ion battery module, compares the state of charge difference with a preset difference threshold, and compares the charge and discharge current mutation amount with a preset disturbance threshold; when the state of charge difference exceeds the preset difference threshold and the charge and discharge current mutation amount does not exceed the preset disturbance threshold, the main control management unit sends an equalization trigger command to the bidirectional active equalization circuit through the independent equalization bus; when the charge and discharge current mutation amount exceeds the preset disturbance threshold, the main control management unit does not send an equalization trigger command to the bidirectional active equalization circuit.

[0033] Specifically, the main control management unit collects charging and discharging current data of the first and second lithium-ion battery modules through a high-precision Hall current sensor. The sampling frequency is 100Hz, the current measurement range is -300A to +300A, and the accuracy is ±0.5%. After digital filtering, the current data is used to calculate the sudden change in charging and discharging current. The filter cutoff frequency is set to 10Hz to effectively filter out high-frequency noise interference.

[0034] It is understandable that the calculation of the state of charge difference uses a real-time comparison method, and the calculation formula is as follows: The preset difference threshold is set to 8%. This preset difference threshold fully considers the actual working conditions of armored vehicles and the battery performance requirements, ensuring both stable system operation and effective triggering of necessary equalization operations. The preset disturbance threshold is set to 15A. When the current fluctuation exceeds this value, the system is determined to be in a high-load operating state, and the equalization operation is suspended to avoid system conflicts.

[0035] In practical applications, the main control management unit continuously monitors the difference in state of charge and the sudden changes in charging and discharging current between the two modules. When both conditions are met... and Under both conditions, the main control management unit sends an equalization trigger command to the bidirectional active equalization circuit via an independent equalization bus. This equalization trigger command uses the CAN protocol format and includes parameter information such as target scheduling power, scheduling direction, and expected scheduling time.

[0036] For example, the formula for calculating the sudden change in charging and discharging current is: ; in, This refers to the sudden change in charging and discharging current. The time-weighted coefficient, It is a time constant; The current value is predicted based on historical data; This is the weighting coefficient for the rate of change of current; The maximum rate of change of current within the sampling window. The sudden change in charging and discharging current combines the weighted standard deviation and the rate of change of current as dual criteria, taking into account not only the amplitude of current fluctuations but also the trend of current changes, thus achieving accurate identification of current disturbances and avoiding misjudgments by traditional methods under complex operating conditions.

[0037] It should be noted that when the detected change in charging and discharging current exceeds the preset disturbance threshold, the main control management unit does not send an equalization trigger command to the bidirectional active equalization circuit, and records the "Equalization pause - large current disturbance" flag in the system status register. At the same time, it sends system status information to the vehicle host via the CAN bus.

[0038] In this embodiment, by introducing a charge / discharge current surge detection and dual-criteria control mechanism, intelligent coordination between the balancing system and the vehicle load is achieved, avoiding system instability that may be caused by balancing operations under heavy load conditions, and significantly improving the reliability and safety of the lithium-ion battery system under complex operating conditions.

[0039] In some embodiments, after the equalization trigger command is issued, the main control management unit continuously collects the charging and discharging current data of the first lithium-ion battery module and the second lithium-ion battery module and updates the charging and discharging current mutation amount; when the charging and discharging current mutation amount exceeds the preset disturbance threshold, the main control management unit sends a pause command to the bidirectional active equalization circuit through the independent equalization bus; after issuing the pause command, the main control management unit continuously monitors the charging and discharging current mutation amount; when the charging and discharging current mutation amount decreases to below the preset disturbance threshold and the duration exceeds the preset stability time, the main control management unit re-collects the state of charge data of the first lithium-ion battery module and the second lithium-ion battery module and recalculates the state of charge difference; when the recalculated state of charge difference exceeds the preset difference threshold, the main control management unit sends a restore equalization command to the bidirectional active equalization circuit through the independent equalization bus; when the recalculated state of charge difference does not exceed the preset difference threshold, the main control management unit ends the current equalization scheduling.

[0040] In practice, after the equalization trigger command is issued, the main control management unit continues to collect charging and discharging current data at a frequency of 100Hz, and updates the charging and discharging current fluctuation every 200ms. This high-frequency monitoring mechanism ensures that the system can respond to current changes in a timely manner, and quickly suspends the equalization operation when a high-load working state is detected, thus avoiding system conflicts.

[0041] Understandably, when a sudden change in charging / discharging current is detected to exceed the preset disturbance threshold (15A), the main control management unit immediately sends a pause command to the bidirectional active balancing circuit via the independent balancing bus. The pause command uses a high-priority CAN message format with a response time ≤50ms, ensuring that the balancing circuit can quickly stop energy scheduling operations. Simultaneously, the main control management unit records the pause timestamp and trigger reason in the system log for easy fault analysis.

[0042] After the pause command is issued, the main control management unit continuously monitors the sudden changes in charging and discharging current, with a monitoring period of 100ms. The preset stabilization time is set to 5 seconds. This time setting fully considers the time characteristics of armored vehicle load switching, ensuring system stability while avoiding excessive waiting time from affecting balancing efficiency. When the sudden changes in charging and discharging current remain below the preset disturbance threshold for 5 consecutive seconds, the system determines that the current state has stabilized.

[0043] In the application, once the current stabilization condition is met, the main control management unit re-acquires the state of charge (SOC) data of the first and second lithium-ion battery modules. The recalculated SOC difference is compared with a preset difference threshold: if... This indicates that balanced scheduling is still required, and the main control management unit sends a restore balanced scheduling command; if This indicates that the equilibrium objective has been achieved or the difference is acceptable, and the main control management unit ends this equilibrium scheduling.

[0044] For example, the calculation formula for the dynamic equilibrium recovery judgment of the preset difference threshold is: ; in, The preset difference threshold is dynamically adjusted; The preset difference threshold is used; This is the time adjustment factor; The duration of the pause; The system's operating cycle is defined by the dynamic equilibrium recovery judgment formula, which dynamically adjusts the threshold: as the pause time increases, the SOC difference threshold required for equilibrium recovery gradually increases, avoiding frequent start-stop cycles caused by brief disturbances and improving system stability.

[0045] It should be noted that the recovery equalization command includes updated scheduling parameters, including the current SOC difference, suggested scheduling power, and expected scheduling time. Upon receiving the recovery command, the bidirectional active equalization circuit restarts the energy scheduling process and continues executing any unfinished equalization tasks.

[0046] In this embodiment, by introducing dynamic monitoring and intelligent recovery mechanisms, adaptive control of the balancing system under complex operating conditions is achieved. This design not only improves the robustness and stability of the system but also optimizes balancing efficiency, ensuring that the lithium-ion battery system can maintain optimal performance under various operating conditions, providing a strong guarantee for the reliable operation of armored vehicles.

[0047] In some embodiments, the system further includes a first DC-DC converter circuit and a second DC-DC converter circuit. The first DC-DC converter circuit is integrated within a first lithium-ion battery module, and the second DC-DC converter circuit is integrated within a second lithium-ion battery module. The input terminal of the first DC-DC converter circuit is connected to the vehicle's main power supply, and the output terminal of the first DC-DC converter circuit is connected to the main control management unit to provide operating power to the main control management unit. The input terminal of the second DC-DC converter circuit is connected to the vehicle's main power supply, and the output terminal of the second DC-DC converter circuit is connected to the slave control management unit to provide operating power to the slave control management unit.

[0048] Specifically, the vehicle's main power supply is a 28V DC power supply. Both the first DC-DC conversion circuit and the second DC-DC conversion circuit are DC-DC conversion circuits, which can convert the input 28V voltage into stable power supplies of different voltage levels such as +5V, +12V, and ±15V to meet the power requirements of different devices such as microcontrollers, sensors, communication modules, and operational amplifiers in the main control management unit and the slave control management unit.

[0049] It is understood that the first and second DC-DC conversion circuits adopt a switching-mode power supply topology, featuring a wide input voltage range (18V-36V), stable output voltage (ripple <100mV), and high conversion efficiency (>85%). The circuit integrates overvoltage protection, undervoltage protection, overcurrent protection, and short-circuit protection functions to effectively protect the downstream management unit circuitry in the event of vehicle power system malfunctions. By integrating an independent DC-DC conversion circuit within each battery module, a distributed power supply architecture is achieved, improving system redundancy and reliability.

[0050] In one specific implementation, the first DC-DC converter circuit has multiple regulated outputs, including a +5V / 2A output for microcontroller power supply, a +12V / 1A output for sensor power supply, and a ±15V / 0.5A output for analog circuit power supply. The second DC-DC converter circuit adopts the same design architecture as the first DC-DC converter circuit, but its power level is optimized to meet the power consumption requirements of the slave control management unit. This distributed power supply design avoids the single point of failure risk that may occur in traditional centralized power supply, significantly improving the safety and stability of the system.

[0051] In some embodiments, based on the above embodiments, a first reverse connection protection diode is connected in series at the input terminal of the first DC-DC conversion circuit, and a second reverse connection protection diode is connected in series at the input terminal of the second DC-DC conversion circuit; the system also includes a main power switch, which is connected in series between the vehicle host power supply and the control coil of the system main switch contactor. After the main power switch is turned on, the vehicle host power supply supplies power to the control coil of the system main switch contactor through the main power switch.

[0052] In practice, both the first and second reverse polarity protection diodes are Schottky diodes, which have the advantages of low forward voltage drop (approximately 0.4V), fast response speed, and stable temperature characteristics. When the polarity of the vehicle's main power supply is reversed, the reverse polarity protection diodes can effectively block the reverse current, preventing damage to the DC-DC conversion circuit and downstream management unit.

[0053] It is understandable that the main power switch uses an industrial-grade rocker switch with IP67 protection rating, a rated current of 15A, and a contact resistance of less than 5 ohms. It can operate reliably in harsh environments. The switch integrates an LED indicator, which can intuitively display the on / off status of the system, making it easy for operators to judge the system's operating status.

[0054] During system operation, the operator first closes the main power switch. The vehicle's 28V power supply, after passing through the main power switch, simultaneously supplies power to the first reverse connection protection diode, the second reverse connection protection diode, and the control coil of the system's main switch contactor. The power supply protected by the reverse connection protection diodes provides input power to the first and second DC-DC conversion circuits, respectively. This design ensures coordinated startup of all parts of the system, avoids system malfunctions caused by timing discrepancies, and effectively prevents equipment damage due to wiring errors through reverse connection protection.

[0055] In this embodiment, by introducing reverse connection protection and centralized power switch control, the safe management and unified control of the system power supply are achieved. The reverse connection protection diode provides the first layer of protection for the system, and the main power switch enables unified power-on control of the system, significantly improving the system's safety and ease of operation.

[0056] In some embodiments, based on the above embodiments, the system further includes a first heating device and a second heating device. The first heating device is disposed on the surface of a first lithium-ion battery module, and the second heating device is disposed on the surface of a second lithium-ion battery module. The output terminal of the first DC-DC converter is also connected to the first heating device to provide operating power to the first heating device. The output terminal of the second DC-DC converter is also connected to the second heating device to provide operating power to the second heating device. The control terminal of the master control management unit is connected to the first heating device, and the control terminal of the slave control management unit is connected to the second heating device.

[0057] In practical implementation, both the first and second heating devices employ flexible silicone heating films with a thickness of 1.5mm. These films utilize uniformly distributed resistance wires, resulting in uniform heating, rapid response, and precise temperature control. Each heating device has a rated power of 100W and an operating voltage of 24V, enabling it to raise the battery temperature from -40℃ to above 0℃, meeting the normal operating requirements of lithium iron phosphate batteries in low-temperature environments.

[0058] It is understandable that the heating film is adhered to the surface of the battery module casing using high thermal conductivity double-sided adhesive to ensure maximum heat transfer efficiency. An NTC temperature sensor is placed between the heating film and the battery casing to achieve closed-loop temperature control. The main control unit and the slave control unit control the power output of the heating device through a PWM pulse width modulation signal, dynamically adjusting the heating power based on real-time temperature feedback. The PWM frequency is set to 1kHz, and the duty cycle adjustment range is 0-100%.

[0059] The first and second DC-DC converters each have independent 24V / 5A output channels dedicated to powering their respective heating devices. These output channels are equipped with independent overcurrent and short-circuit protection, with a protection threshold set at 6A and a response time of less than 100μs. This design ensures the independence of the heating function; even if one DC-DC converter fails, it will not affect the heating function of the battery module on the other side, improving the system's reliability in extreme environments.

[0060] In this embodiment, precise temperature control of the lithium-ion battery module is achieved through an integrated heating device and distributed power management. The close fit between the heating device and the battery module ensures heating efficiency, while the independent power supply and intelligent control system ensure the reliability and accuracy of the heating function, significantly improving the system's ability to operate in low-temperature environments.

[0061] In some embodiments, based on the above embodiments, the master control management unit collects temperature data of the first lithium-ion battery module, and the slave control management unit collects temperature data of the second lithium-ion battery module; when the temperature data is lower than a first preset threshold and the vehicle generator is in operation, the corresponding management unit starts the corresponding heating device; when the temperature data is lower than a second preset threshold, the corresponding management unit controls the corresponding heating device to enter an emergency heating mode; when the temperature data rises to a third preset threshold, the corresponding management unit shuts down the corresponding heating device; wherein, the second preset threshold is lower than the first preset threshold, and the third preset threshold is higher than the first preset threshold.

[0062] In practice, the temperature thresholds are set as follows: the first preset threshold is 5℃, the second preset threshold is -15℃, and the third preset threshold is 15℃. These threshold settings fully consider the operating characteristics of lithium iron phosphate batteries and the actual operating environment of armored vehicles, ensuring optimal battery performance under different temperature conditions.

[0063] It is understandable that the main control unit and the slave control unit are each configured with 4 temperature acquisition channels, and each battery module is equipped with 4 temperature sensors, distributed in the four corners of the battery module, to ensure comprehensive and accurate temperature monitoring. The temperature sensors use high-precision NTC thermistors, with a temperature measurement range of -40℃ to +85℃, an accuracy of ±0.5℃, and a response time of less than 5 seconds.

[0064] The intelligent temperature control logic in this embodiment includes: (1) Normal heating mode: When any temperature sensor detects that the temperature is below 5°C and the vehicle generator is detected to be in working state via the CAN bus, the corresponding management unit starts the heating device, and the initial power is set to 30% of the rated power. The management unit collects temperature data every 10 seconds and dynamically adjusts the heating power according to the temperature change trend.

[0065] (2) Emergency heating mode: When the temperature is below -15℃, regardless of whether the generator is working, the management unit immediately controls the heating device to work at 100% rated power and sends a low temperature alarm signal to the vehicle host. In emergency heating mode, the temperature acquisition frequency is increased to once every 5 seconds to ensure rapid response.

[0066] (3) Heating stop: When all temperature sensors detect that the temperature has risen above 15°C, the management unit shuts down the corresponding heating device to avoid energy waste and battery performance impact caused by overheating.

[0067] (4) Temperature equalization control: During the heating process, the management unit monitors the data of each temperature sensor in real time and achieves precise temperature control by adjusting the PWM duty cycle. When the internal temperature difference of the battery module exceeds 3°C, the system automatically adjusts the heating power distribution to ensure that the temperature of each part of the battery module rises evenly.

[0068] In the application, generator status is acquired in real time via the CAN bus, and the detected parameters include generator speed, output voltage, and charging current. When the generator speed is greater than 800 rpm and the output voltage is greater than 26V, the generator is determined to be in normal operating condition.

[0069] In this embodiment, the temperature control strategy not only ensures the normal operation of the battery in low-temperature environments but also optimizes energy utilization and extends the system's range through intelligent power regulation and generator status detection. Distributed temperature monitoring and graded heating control enable precise temperature management of the lithium-ion battery module, significantly improving the system's reliability and practicality in extreme low-temperature environments, and providing strong support for the combat capabilities of armored vehicles in frigid regions.

[0070] In some embodiments, the slave control management unit also collects the cell voltage, module current and temperature in the second lithium-ion battery module, and independently performs overcharge protection, over-discharge protection, overcurrent protection and short circuit protection on the charging and discharging circuit of the second lithium-ion battery module based on the cell voltage, module current and temperature.

[0071] Specifically, the control and management unit integrates high-precision voltage detection circuits, current detection circuits, and temperature monitoring circuits to monitor multiple cells within the second lithium-ion battery module in real time. The voltage detection circuit uses a high-precision ADC, achieving a voltage measurement accuracy of ±5mV, accurately detecting the terminal voltage of each cell. The current detection circuit uses a Hall effect current sensor, with a current measurement range of -200A to +200A and an accuracy of ±1%, enabling real-time monitoring of the module's charging and discharging current. The temperature monitoring circuit is equipped with multiple NTC temperature sensors distributed at different locations within the battery module, achieving a temperature measurement accuracy of ±1℃.

[0072] It is understandable that the slave control unit possesses independent protection decision-making capabilities, independently executing corresponding protection operations based on the collected cell voltage, module current, and temperature data. The overcharge protection threshold is set at a single cell voltage ≥ 3.65V; upon triggering, the slave control unit immediately disconnects the charging circuit to prevent safety risks caused by overcharging. The over-discharge protection threshold is set at a single cell voltage ≤ 2.5V; upon triggering, the slave control unit cuts off the discharge circuit to avoid irreversible damage caused by over-discharge.

[0073] Overcurrent protection is divided into two modes: charging overcurrent protection and discharging overcurrent protection. The charging overcurrent protection threshold is set to ≥50A and the duration is ≥200ms, while the discharging overcurrent protection threshold is set to ≥150A and the duration is ≥100ms. Short circuit protection adopts a fast response mechanism. When a short circuit is detected at the module output, the slave control unit cuts off the discharge circuit within 50μs and sends a fault alarm message to the master control unit.

[0074] Through the aforementioned independent protection mechanism, the slave control management unit can provide comprehensive safety protection for the second lithium-ion battery module without relying on the master control management unit, significantly improving the safety and reliability of the system.

[0075] In some embodiments, both the first lithium-ion battery module and the second lithium-ion battery module are composed of multiple lithium iron phosphate cells, which are connected in series in groups of eight and in parallel in multiple groups to form the first lithium-ion battery module and the second lithium-ion battery module.

[0076] In practical implementation, both the first and second lithium-ion battery modules use lithium iron phosphate (LiFePO4) cells as the basic energy storage unit. Lithium iron phosphate cells have the characteristics of stable operating voltage (nominal voltage 3.2V), excellent safety performance, long cycle life (>2000 cycles), and good temperature characteristics, making them particularly suitable for use in the harsh environment of armored vehicles.

[0077] It is understandable that the lithium iron phosphate cells within each battery module are connected in an 8-series, multi-parallel configuration. This means eight cells are connected in series to form a basic battery string, and multiple basic battery strings are connected in parallel to form a complete battery module. The 8-series connection allows the module's nominal voltage to reach 25.6V (8 × 3.2V), matching the 24V power system of armored vehicles. The multi-parallel connection can be flexibly configured according to the power requirements of the armored vehicle; a typical configuration is 8 series and 4 parallel, with a single module capacity reaching 200Ah, capable of meeting the dual requirements of high-power starting and long-term standby in armored vehicles.

[0078] In this application, square hard-shell lithium iron phosphate cells are used, with a single cell capacity of 50Ah, a maximum continuous discharge current of 2C (100A), and a maximum pulse discharge current of 5C (250A), which can provide the high power output required for starting the engine of armored vehicles. The cell operating temperature range is -20℃ to +60℃, and with the addition of a heating device, the system operating temperature range can be extended to -40℃ to +60℃.

[0079] For example, the internal cell connections of the module are made using laser-welded nickel sheets to ensure connection reliability and conductivity. Insulating partitions and shock-absorbing materials are placed between the cells to effectively prevent damage from vibration and impact. Through this design, each lithium-ion battery module achieves high energy density while possessing excellent mechanical strength and environmental adaptability, meeting the demanding operating conditions of armored vehicles.

[0080] In some embodiments, the isolated communication bus is an electrically isolated controller area network (Controller Area Network) bus. The slave management unit sends voltage, current, and temperature data of the second lithium-ion battery module to the master management unit through the electrically isolated Controller Area Network bus, and the master management unit receives the voltage, current, and temperature data through the electrically isolated Controller Area Network bus.

[0081] In its implementation, the isolated communication bus adopts a Controller Area Network (CAN) bus based on the ISO11898 standard, which has high anti-interference capability and strong real-time performance, enabling it to operate stably in the complex electromagnetic environment of armored vehicles. The CAN bus operating rate is set to 250kbps, ensuring both real-time data transmission and communication stability.

[0082] It is understandable that the isolated communication bus employs magnetic isolation technology at the physical layer, achieving an isolation voltage of 2500VDC, effectively blocking the electrical connection between the two battery modules and preventing fault current from propagating between modules. The magnetic isolation devices utilize an industrial-grade design, operating within a temperature range of -40℃ to +85℃, meeting the full-temperature requirements of armored vehicles. The isolated communication bus is equipped with an independent power module, providing a stable power supply to the isolation devices and ensuring the reliability of the communication link.

[0083] During data transmission, the slave control unit encapsulates the voltage, current, and temperature data of the second lithium-ion battery module into standard CAN data frames according to a predetermined CAN message format. The data frame uses a 29-bit extended identifier, containing information such as module identifier, data type, and timestamp. The voltage data accuracy is 1mV, the current data accuracy is 0.1A, and the temperature data accuracy is 0.1℃. The data transmission cycle is 100ms, ensuring that the master control unit can obtain the real-time status of the second lithium-ion battery module in a timely manner.

[0084] After receiving data, the main control unit performs CRC checks and data validity verification to ensure the accuracy of the received data. This electrically isolated CAN bus communication method enables safe and reliable data exchange between the two battery modules, providing a fundamental guarantee for the coordinated control of the system.

[0085] In some embodiments, the data reported by the slave control management unit to the master control management unit may also include the state of charge data and fault codes of the second lithium-ion battery module. The master control management unit controls the on / off state of charge of the system main switch contactor based on the state of charge data and fault codes reported by the slave control management unit, combined with the state of charge data and fault codes of the first lithium-ion battery module.

[0086] In practice, the slave control unit uses the ampere-hour integration method combined with the open-circuit voltage method to calculate the state of charge (SOC) of the second lithium-ion battery module, achieving a calculation accuracy of ±3%. The SOC data is expressed as a percentage, ranging from 0% to 100%, with a resolution of 0.1%. The slave control unit updates the SOC data once per second and transmits it to the master control unit via an isolated communication bus.

[0087] It is understandable that the fault codes adopt a standardized encoding format, covering various fault types such as cell overvoltage, undervoltage, overtemperature, overcurrent, and communication abnormalities. The fault code is 16 bits long, with the high 8 bits indicating the fault type and the low 8 bits indicating the specific fault location. When a fault is detected, the slave control unit immediately generates the corresponding fault code and sends it to the master control unit via the CAN bus in the form of a high-priority message.

[0088] After receiving the state-of-charge data and fault codes reported by the slave control unit, the master control unit, in conjunction with the status information of the local first lithium-ion battery module, executes system-level decisions. The control logic of the system's main switch contactor is as follows:

[0089] (1) Normal working conditions: When the SOC of both modules is ≥20% and there is no serious fault, the main control management unit keeps the system main switch contactor closed and the system supplies power to the vehicle normally.

[0090] (2) Low battery protection: When any module's SOC is less than 10%, the main control management unit disconnects the system's main switch contactor to prevent irreversible damage caused by deep battery discharge.

[0091] (3) Fault protection: When a serious fault code (such as short circuit, over-temperature, insulation failure, etc.) is received, the main control management unit immediately disconnects the system main switch contactor and sends a fault alarm signal to the vehicle host.

[0092] (4) SOC imbalance handling: When the SOC difference between two modules is ≥15%, the main control management unit starts the bidirectional active balancing circuit to achieve SOC balance between modules through energy transfer.

[0093] In application, the main control management unit also has fault recording and diagnostic functions, capable of storing historical fault information and system operating parameters, providing data support for system maintenance and fault analysis. Through comprehensive control strategies, the safe and reliable operation of the lithium-ion battery system under various working conditions is ensured, significantly improving the intelligence level of the armored vehicle power system.

[0094] In this embodiment, comprehensive status monitoring of the lithium-ion battery system is achieved by integrating state-of-charge monitoring and fault diagnosis functions. The main control management unit, based on multi-source data fusion, intelligently controls the system's main switch contactor, effectively protecting the battery system's safety, extending its service life, and providing reliable power supply for armored vehicles.

[0095] In some embodiments, please refer to Figure 2 This is a block diagram of the BMS in this embodiment, illustrating the core architecture and functional modules of the battery management system. The BMS uses the MCU minimum system as the core control unit and achieves comprehensive monitoring and management of the battery system through multiple functional modules.

[0096] Specifically, the telecommunications module and the total power signal conditioning module are responsible for collecting eight analog signals of cell voltage and total voltage to ensure accurate monitoring of the voltage of each individual cell and the overall battery pack. The power module converts the +28V vehicle power supply to stable +5V and ±15V power supplies, providing reliable operating power for the various functional modules of the BMS. The charge / discharge current sampling module monitors the battery's charge / discharge current in real time using a high-precision current sensor, providing fundamental data for SOC calculation and power management.

[0097] The equalization management module integrates an active equalization circuit, enabling energy transfer between cells and eliminating voltage differences between individual cells. The temperature control module performs three functions: temperature acquisition and analog signal processing, heating power management, and over-temperature protection (including both hardware and software protection mechanisms) to ensure safe battery operation under various temperature conditions. The communication interface module achieves data exchange with external systems via UART and level conversion, supporting the CAN bus communication protocol. An external EEPROM stores system configuration parameters and historical data, while a watchdog reset circuit provides hardware-level security for the system.

[0098] Figure 2 It embodies the design concept of a distributed battery management system, and through modular functional division and multi-level protection mechanisms, it achieves intelligent management and all-round protection of lithium-ion battery systems.

[0099] In some embodiments, the performance parameters of the original lead-acid battery and the battery module of the present invention are compared, and the comparison results in Table 1 are obtained. Table 1 Comparison of performance parameters between the original lead-acid battery and the battery module of this invention ; As shown in Table 1, by comparing and analyzing the key performance parameters of the original lead-acid battery and the battery module of the present invention, the significant advantages of the lithium-ion battery system of the present invention can be clearly seen.

[0100] Specifically, while maintaining the same single-cell battery capacity (130Ah), the nominal voltage of the battery module of this invention is increased from 24V to 25.6V, better matching the operating requirements of the vehicle's 24V electrical system. The most significant improvement is in energy density: the battery module of this invention achieves 74.0Wh / kg, a 61.6% increase compared to the original lead-acid battery's 45.8Wh / kg, achieving a significant weight reduction effect.

[0101] Understandably, the battery module of this invention exhibits superior power characteristics in terms of charge and discharge performance. The continuous charging rate is significantly increased from 0.5Cs to 3Cs, with a 6-fold improvement in charge acceptance and a substantial reduction in charging time. The continuous discharging rate jumps from 3Cs to 10Cs, increasing discharge capacity by 233%, providing stronger starting power. The weight of a single battery pack is reduced from 68kg to 45kg, a weight reduction of 33.8%, significantly reducing the vehicle's burden and improving equipment mobility and fuel economy.

[0102] As can be seen from Table 1, the lithium-ion battery system of the present invention achieves multiple optimizations such as weight reduction, power increase and charging acceleration while maintaining the same capacity, providing an ideal solution for the modernization and upgrading of the power system of armored vehicles, and fully verifying the advanced nature and practicality of the technical solution.

[0103] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lithium-ion battery system for in-situ replacement of parallel lead-acid batteries in armored vehicles, characterized in that, The system includes a first lithium-ion battery module, a second lithium-ion battery module, a main control management unit, a slave control management unit, and a system main switch contactor. The first lithium-ion battery module and the second lithium-ion battery module are connected in parallel. The main control management unit is integrated into the first lithium-ion battery module, and the slave control management unit is integrated into the second lithium-ion battery module. The slave control management unit is connected to the master control management unit through an isolated communication bus, and reports the voltage, current and temperature data of the second lithium-ion battery module to the master control management unit; The system master switch contactor is connected in series in the charging and discharging circuits of the first lithium-ion battery module and the second lithium-ion battery module. The control terminal of the system master switch contactor is connected to the main control management unit. The main control management unit controls the on / off state of the system master switch contactor according to the voltage, current and temperature data reported by the slave control management unit. Each lithium-ion battery module has the same external dimensions, installation method, and electrode terminals as the lead-acid battery it is replacing.

2. A lithium-ion battery system for in-situ replacement of parallel lead-acid batteries in armored vehicles as described in claim 1, characterized in that, The system also includes a bidirectional active balancing circuit and an independent balancing bus. The bidirectional active balancing circuit is respectively disposed in the first lithium-ion battery module and the second lithium-ion battery module. The independent balancing bus is used to connect the first lithium-ion battery module and the second lithium-ion battery module. The data reported by the slave control management unit to the master control management unit also includes the state of charge (SOC) data of the second lithium-ion battery module. The master control management unit compares the SOC data of the second lithium-ion battery module with the SOC data of the first lithium-ion battery module. When there is a difference, the master control management unit controls the bidirectional active balancing circuit to perform energy scheduling between the first and second lithium-ion battery modules through the independent balancing bus. The master control management unit prioritizes energy scheduling between the first and second lithium-ion battery modules and then performs energy scheduling between the cells within each lithium-ion battery module.

3. A lithium-ion battery system for in-situ replacement of parallel lead-acid batteries in armored vehicles as described in claim 2, characterized in that, The main control management unit also collects charging and discharging current data of the first lithium-ion battery module and the second lithium-ion battery module, and calculates the charging and discharging current mutation amount based on the charging and discharging current data. The main control management unit calculates the state of charge difference between the state of charge data of the first lithium-ion battery module and the state of charge data of the second lithium-ion battery module, compares the state of charge difference with a preset difference threshold, and compares the charge and discharge current mutation with a preset disturbance threshold. When the state of charge difference exceeds the preset difference threshold and the sudden change in charge / discharge current does not exceed the preset disturbance threshold, the main control management unit sends an equalization trigger command to the bidirectional active equalization circuit through the independent equalization bus; when the sudden change in charge / discharge current exceeds the preset disturbance threshold, the main control management unit does not send an equalization trigger command to the bidirectional active equalization circuit.

4. A lithium-ion battery system for in-situ replacement of parallel lead-acid batteries in armored vehicles as described in claim 3, characterized in that, After the equalization trigger command is issued, the main control management unit continuously collects the charging and discharging current data of the first lithium-ion battery module and the second lithium-ion battery module and updates the charging and discharging current mutation amount. When the sudden change in the charging and discharging current exceeds the preset disturbance threshold, the main control management unit sends a pause command to the bidirectional active balancing circuit through the independent balancing bus. After issuing the pause command, the main control management unit continuously monitors the charge and discharge current fluctuation. When the charge and discharge current fluctuation drops below the preset disturbance threshold and lasts for more than the preset stable duration, the main control management unit re-collects the state of charge data of the first lithium-ion battery module and the state of charge data of the second lithium-ion battery module and recalculates the state of charge difference. When the recalculated state of charge difference exceeds the preset difference threshold, the main control management unit sends a recovery equalization command to the bidirectional active equalization circuit through the independent equalization bus. When the recalculated state of charge difference does not exceed the preset difference threshold, the main control management unit ends the current balance scheduling.

5. A lithium-ion battery system for in-situ replacement of parallel lead-acid batteries in armored vehicles as described in claim 1, characterized in that, The system also includes a first DC-DC conversion circuit and a second DC-DC conversion circuit, wherein the first DC-DC conversion circuit is integrated into the first lithium-ion battery module and the second DC-DC conversion circuit is integrated into the second lithium-ion battery module. The input terminal of the first DC-DC converter is connected to the vehicle's main power supply, and the output terminal of the first DC-DC converter is connected to the main control management unit to provide operating power to the main control management unit. The input terminal of the second DC-DC converter is connected to the vehicle's main power supply, and the output terminal of the second DC-DC converter is connected to the slave control management unit to provide operating power to the slave control management unit.

6. A lithium-ion battery system for in-situ replacement of parallel lead-acid batteries in armored vehicles as described in claim 5, characterized in that, The input terminal of the first DC-DC converter circuit is connected in series with a first reverse polarity protection diode, and the input terminal of the second DC-DC converter circuit is connected in series with a second reverse polarity protection diode. The system also includes a main power switch, which is connected in series between the vehicle's main power supply and the control coil of the system's main switch contactor. When the main power switch is turned on, the vehicle's main power supply supplies power to the control coil of the system's main switch contactor through the main power switch.

7. A lithium-ion battery system for in-situ replacement of parallel lead-acid batteries in armored vehicles as described in claim 5, characterized in that, The system also includes a first heating device and a second heating device, wherein the first heating device is disposed on the surface of the first lithium-ion battery module and the second heating device is disposed on the surface of the second lithium-ion battery module; The output of the first DC-DC converter is also connected to the first heating device to provide power to the first heating device. The output of the second DC-DC converter is also connected to the second heating device to provide power to the second heating device. The control terminal of the master control management unit is connected to the first heating device, and the control terminal of the slave control management unit is connected to the second heating device.

8. A lithium-ion battery system for in-situ replacement of parallel lead-acid batteries in armored vehicles as described in claim 7, characterized in that, The main control management unit collects temperature data from the first lithium-ion battery module, and the slave control management unit collects temperature data from the second lithium-ion battery module. When the temperature data is lower than a first preset threshold and the vehicle generator is in operation, the corresponding management unit activates the corresponding heating device. When the temperature data is lower than a second preset threshold, the corresponding management unit controls the corresponding heating device to enter an emergency heating mode. When the temperature data rises to a third preset threshold, the corresponding management unit shuts down the corresponding heating device. The second preset threshold is lower than the first preset threshold, and the third preset threshold is higher than the first preset threshold.

9. A lithium-ion battery system for in-situ replacement of parallel lead-acid batteries in armored vehicles as described in claim 1, characterized in that, The slave control management unit also collects the cell voltage, module current, and temperature in the second lithium-ion battery module, and independently performs overcharge protection, over-discharge protection, overcurrent protection, and short-circuit protection on the charging and discharging circuit of the second lithium-ion battery module based on the cell voltage, module current, and temperature.

10. A lithium-ion battery system for in-situ replacement of parallel lead-acid batteries in armored vehicles as described in claim 1, characterized in that, Both the first lithium-ion battery module and the second lithium-ion battery module are composed of multiple lithium iron phosphate cells. The multiple lithium iron phosphate cells are connected in series in groups of eight and in parallel in multiple groups to form the first lithium-ion battery module and the second lithium-ion battery module.

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