The Research And Design Of Power Li-ion Battery Management System

Energy shortages and environmental pollution are two major challenges the automobile industry faced, so that it is very urgent to research and develop the new engery-saving and environemently-friendly energy vehicles. Pure electric vehicle is following increased emphasis by the world, for that it is zero emissions and low noise advantages. Battery management system, as one of the key technologies for the development of electric vehicles, is the key of electric vehicles industrialization.This thesis is devoted to design a management system for36V,80Ah lithium batterie group. This thesis introduces and analyzis some existing battery model, and chooses the popular thevenin model and identify the system for charge and discharge direction by HPPC circulation experiment. State space model for extended Kalman filter algorithm is proposed based on Ampere-hour method. The accuracy and convergence of the algorithm is verified by using Matlab software.According to the requirements of the battery management system, this thesis designs the system hardware and software. This system uses two control structures, and uses RS-485bus for communication. The main chip of central electric control unit is C8051F410MCU, and the local electric control unit is TMS320F2812DSP. The main functions are: to collect the real-time datas of the battery group, including the single voltage, current, temperature, total voltage and total current; to estimate the state of charge of the battery group, using open-circuit voltage method and extended Kalman filter algorithm based on the collected datas; to diagnosis and balance the single battery voltage inconsistencies in the battery charge process; to diagnosis and alarm the battery failures.Finally, this thesis berifis the voltage and current acquisition accuracy by the data acquisition accuracy test and verify the equilibrium effects of this system by cell balancing test.