Study On The Lithium Battery Management System Based On Ternary Lithium Battery

Due to energy shortage and environmental pollution,electric vehicles have become an inevitable trend to replace fuel vehicles.Lithium battery is more and more widely used in new energy vehicle because of its many advantages compared with other energy storage batteries.Compared with other kinds of lithium batteries,ternary lithium batteries have many advantages,such as high specific energy,good low temperature characteristics and low cost.However,the safety and service life of ternary lithium batteries are limited because of their own material characteristics.Therefore,a battery management system is designed based on ternary lithium battery.Firstly,the characteristics of the ternary lithium battery and other common power batteries are compared,and it is concluded that the ternary lithium battery has the advantages of high specific energy and long cycle life.The composition and chemical characteristics of the ternary lithium battery are described,and the group mode of the ternary lithium battery is selected.The typical equivalent circuit model of lithium battery is analyzed and the Thevenin model is used as the equivalent circuit model of ternary lithium battery.The extended Kalman filter algorithm is used to estimate the SOC.The iterative process of the extended Kalman filter algorithm is deduced in detail,and the simulation is carried out by MATLAB software.The simulation curve and estimation error are obtained by analysis.The hardware design of the monitoring module of the battery management system is carried out,and the voltage,current and temperature monitoring circuits are designed.The measuring accuracy of the monitoring module and the precision of SOC estimation by amperage method are tested and verified.The simulation results of SOC estimation using extended Kalman filter algorithm show that the extended Kalman filter algorithm can accurately estimate the battery SOC,and the estimation error is within the allowable range.The test results of the monitoring module show that the precision of the voltage,circuit and temperature monitoring module is in line with the requirements of the battery management system.The estimation accuracy of extended Kalman filter is higher than that of SOC.