Lithium Battery Management System Of Portable Backup Power

Portable backup power has many characteristics, such as flexible, portable, and it is used in the field of communication, travel and adventure, medical aid and other power shortage scenario. With the rapid development of lithium battery technology, long working life have been increasingly used in portable backup power supply because of its high energy ratio. Portable backup power makes the lithium battery series-parallel to obtain higher output voltage and power. However, the poor consistency of the battery parameters between the initial capacity, the voltage and the resistance, resulting in the lower utilization of battery energy, shortened life expectancy and other problems which may lead to serious accidents.In this paper, lithium battery pack of the Portable backup power has been researched and analyzed. Through the comparing of current implementations and methods, also considering the power efficiency and designed cost, the proactive balanced lithium battery management system was implemented based on Android system.The main tasks are:(1) System architecture Modular design, using the bus to expand and dismantle lithium batteries module, and managing multiple sets of lithium batteries.(2) Hardware design of the battery management system, it is divided into BMS control module, battery equalization module and data acquisition processing module. BMS control module which uses Tiny210 as the main control center, based on the Android platform to display and management the battery pack running parameter, record the charge and discharge parameter and safety tips, Battery equalization module using BQ78PL116 and BQ78PL102 as battery pack monitoring chip; battery data acquisition processing module using STM8 S microcontroller as the processor, combined with battery parameters to judge and control working status, complete the converter of communication signals between BMS control module and Battery equalization module.(3) SOC estimation method uses a hardware combination with software, BMS control module auxiliary Battery equalization module to get accurate SOC estimates; Considering heat balance and equilibrium rate, the battery pack use different balancing strategy in different working state, such as discharge state using the maximum and minimum method, idle state using the average value method, charge state using the improved average method, then using inductive active equalization scheme to balance battery pack.(4) Complete the software design of lithium batteries balancing strategy, parameter measurement, communication protocols, and communication flow.(5) To achieve each module system testing, and then test the entire system, verify that the system meet the requirement and work normally and run stably.This lithium batteries management system achieves the centralized management of multiple sets of lithium batteries, ensures the safe of lithium batteries, and improves the life of lithium batteries. The system has been tested and verified that the portable backup power lithium battery pack management system can be operated safe, convenient, and efficient.