The Electric Vehicle Battery Management System Based On PIC24HJ256GP610

Electric Vehicles is a kind of new type automobiles by battery pack with lower emission and lower fuel consumption. It has bright prospects. During recent years, governments and research institutions are increasing investment into the electric vehicle industry, which has brought its rapid development. Experts predict that electric vehicles will replace traditional fuel vehicles in the near future. At present, the electric vehicle mainly has the problems of poor endurance ability, short battery life and poor operational reliability. All-electric vehicle was equipped with batteries as power source, so the battery performance of the merits direc tly determines the level of performance of electric vehicles. Battery management system is the key to the safe operation of battery and car.(BMS) Battery management system is not only an important part of electric vehicle, but also is very important to electric vehicles.This paper analyzed the BMS based on PIC24HJ256GP610. It included three part those are hardware design, software design and communication module. This paper gave detailed introduction to the design of hardware circuit and software of collection of voltage, current and temperature, battery protection, balance control and estimation of state of charge.First, the paper discussed advantages and disadvantages of lithium iron phosphate battery and the charge and discharge characteristics of the battery. And then, based on analyzing the research create equivalent model to estimate state of charge(SoC) by using Extended Kalman Filter(EKF)combine with OCV(open-circuit voltage). Experimental validation of the SoC assessment of the deviation is not more than 5%.Second,using the PIC24HJ256GP610 and LTC6802 as main chip, the electric vehicle battery management system platform structures was completed. the system was designed in modularization, including power module, monitoring module and communication module. In addition, the system software mainly completed the transfer and exchange of battery status information in the system. The date from the voltage, current and temperature were monitored communicate with PC and main controller by SPI bus and CAN bus. It was in order to complete the balance control and safety protection of batteries.The last,it had proved the system designed in this paper which realized the system's hardware and software. The safe operation of battery was protected well through the BMS. The system was reliable and meets the design requirements.