| Since problems of air pollution, global warming and depletion of the Earth’s petroleum resources are becoming more serious, the development and application of new energy have been emphasized around the world. On utilization of the new energy, the development of electric vehicle is paid more and more attention. Batteries are the main power unit or auxiliary power unit of electric vehicles. However during the use of the battery there exist problems of safety and reliability issues, so we need to close monitoring and management of the battery.This thesis did research on the remaining capacity calculation method and management system of power battery on the basis of understanding and analyzing the characteristics of lithium iron phosphate battery through experiments. First, the second order equivalent circuit model of the power battery was established. The pulse charge and discharge experiments to a lithium iron phosphate battery cell were accomplished to acquire the parameters of the battery model built in discuss. Current impact factors were taken into account in determining the model parameters in order to improve the accuracy of the model of the power battery. Based on the established power battery model, the Extended Kalman Filter (EKF) algorithm was applied to estimate the State of Charge (SOC) of the power battery, we also compared the estimation results to the experimental values for more analyze.Then theory analysis to driving range of electric vehicles was carried out, and we put the EKF-based algorithm SOC estimation into the calculation of the driving range of electric vehicles. Taking a pure electric vehicle as an example, the established vehicle simulation model based on MATLAB/Simulink was used to simulate its remaining driving range, and the calculated values are compared with the actual values.Finally, hardware and software design of the battery management system were carried out. A testing bench based on the dSPACE, programmable power supply and electronic load was built to verify the data measurement accuracy and CAN bus communication function of the battery management system.The experiment results show that the designed management system here can collect the status information of battery including battery pack voltage, current and cell voltage in high precision. It can also send battery status information through the CAN bus to meet the requirements of the battery management system. |
