Study On Software Design Of Lithium-ion Battery Management System And Strategy Of The SOC Estimation

The car is necessary vehicle in human life, but its emissions and energy consumption has become a problem. Electric car has become one of the best solution to this problem. The advantages of electric car is zero emissions, low consumption, highly intelligent etc, and it has become the future development of the car industry. However, storage and management technology of power battery restricts the development of electric car. How to improve the efficiency of battery, how to lengthen the life of battery and how to enhance the safety of battery has become the main research area. So, the battery management system emerges at the right moment.Battery management system is used to monitor the battery, improve the efficiency and safety, and reduce the cost. In this paper, the design of battery management system is for lithium-ion battery. According to the analysis on the operating characteristics of the battery, Thevenins Model is chosen to be the battery model of lithium-ion battery, and on that basis the estimation of battery charge state (SOC) is given. On the acknowledgement of the shortage of traditional methods to estimate SOC, the extended Kalman Filter is adopted in this paper. Ah counting method and voltage method are combined, and the closed loop estimation of lithium ion battery SOC is realized, which is accurate and meets the programming design requirement.The hardware platform of system is also described in this paper, using module design. To different function module, the software design of the system is also described, including the main program and its relevant program, the data acquisition module program, the control part program and CAN communication module program. The program flow chart is shown in details.System test and car experiment prove that the design of battery management system proposed in this paper has the high data acquisition accuracy, and can estimate SOC accurately. And the balance between the battery is realized, which ensures the consistency of battery, efficiency of battery is improved and the service life of battery is lengthened.