Research On Lithium Iron Phosphate Battery Management System Of Electric Vehicle

The energy crisis of modern society made people realize that the traditional internal combustion engine needs to take advantage of new energy. Energy consumption in the cars of all the major industrial countries in the proportion of energy consumption to 24%, which prompted the world's major industrial enterprises and automobile production countries speeding up its development of the automotive battery in the application. Electric Vehicle Battery Management System (BMS) is an increasingly important part of the key to the electric car.China has just started the research in this area; the auto industry developed countries such as Germany and the United States, whose development work also is not yet perfect.In this paper, a new type of electric vehicle battery management system is designed in the actual electric vehicle application of Chang'an "Ben Ben". The design had been tested the reliability of the system and practicality through the theoretical derivation, Saber simulation and hardware experiment. The main research results are as follows:Firstly, the driving force for all existing energy batteries, Panasonic EV Energy Management System for a more detailed comparative study, a comparative analysis of various parameters of the merits of system performance. At the same time, the system currently used by the latest version of dynamic energy batteries - lithium iron phosphate battery( LiTePO4 ), a more detailed analysis of the experimental study, obtained the experimental data at different temperatures, different discharge current, and phosphoric acid application of lithium iron battery to a new view;Secondly, in view of lithium iron phosphate unique battery charge and discharge characteristics of existing power battery SOC (battery state-of-charge) algorithm characteristics, as well as traditional methods in the lithium iron phosphate is not on the applicability of battery; use Neural Network and the battery SOC Kalman filtering method were exploratory study. At the same time,the paper proposes a suitable lithium iron phosphate unique battery charge and discharge curve of the new algorithm, the algorithm in the new algorithm to compensate for the existing temperature impact of the lack of consideration;Thirdly, according to the system as a whole, as well as the specific requirements of the electric car project design goals, determine the hardware circuit design and components of the selection. Acquisition of the differential voltage circuit to the linear thermistor temperature measurement circuit, A / D sampling circuit filter circuit, CAN communications circuits and power modules, a comprehensive comparison of the demonstration programme, a very good solution, such as how to achieve high total Die-voltage operational amplifier input, and other issues.This paper is mainly to solve problems such as the difficulty of the existing low-cost measurement series battery high common-mode voltages, have not been raised specifically for lithium iron phosphate battery SOC estimated online algorithm, the impact of temperature to the battery discharge are not fully considered.