Development Of Battery Management System Experiment Platform

As the dual advantages of energy saving and environmental protection, electric vehicles are developing rapidly worldwide in recent years. However, battery management system is a bottleneck restriction to electric vehicles development. Electric vehicle battery management system necessarily solves problems on State of Charge (SOC) estimation, balanced charge and discharge achievement and prolonging battery life span. The effective monitoring and management of battery pack for solving problems forenamed have important theoretical significance and practical value, which can effectively promote the practicality and commercialization of electric vehicles.According to characteristics of the lithium iron phosphate battery, a battery management system testing platform is designed to detect and process the battery performance parameters, including the module voltage, temperature, the pack voltage and current. In addition, the battery management system testing platform has more perfect functions, realization of battery charger and temperature controlling and status signals receiving by relay controlling and digital input signal conditioning.The function and reliability of the testing platform are validated. Charge and discharge experiments are conducted at different current using charger and discharge instrument, the real-time monitoring of module voltage and the pack voltage is carried on and the effect of current to the battery voltage in the same SOC is analyzed. The current integration method is to estimate the SOC variable, for calculation accuracy of SOC with different sampling frequency and accuracy to the current experimental curves collected is studied to provide the basis for practical application of the battery management system SOC estimation. Project also analyzed the inconsistencies in the single cell battery pack could be released on the impact of electricity.The imbalance of battery packs in series using exists, which is validated with the inconsistencies of module voltage monitored by the testing platform during the battery charge or discharge process. Battery imbalance is harmful to the battery pack, which not only reduces the battery pack efficiency, but also will shorten its life cycle. To solve the imbalance of the battery pack, various methods of balanced charge and discharge are carried out, but mostly in the theoretical analysis phase. By model building of battery and balanced model using MATLAB/Simulink, the charge and discharge is simulated. Varieties of charge and discharge simulation results are compared and the advantages and disadvantages are analyzed to provide theoretical basis for practical application.