Research On Battery Management System For Extended-range Electric Car

Due to environment problem and energy crisis becoming increasinglyprominent, electric-vehicle technologies gain much more focus. In respect of lifecycle analysis, electric vehicle’s influence to environment decreases with theproportion of clean energy in the grid increasing. Meanwhile, EV has the functionof peak shaving and valley filling in power grid. Pure electric vehicle is short ofdriving mileage and Hybrid Electric Vehicle’s structure is complex, extended-rangeelectric car solves these problems. Battery management system is necessary toextending life of secondary battery that be power source of electric vehicle, in caseof secondary battery is easy to damage.Firstly, this paper analyses the characteristics of accumulator battery cell.Based on the structure of extended-range electric car, this paper comparescentralized BMS with decentralized BMS. Considering their merits and demerits,this paper adopts the decentralized structure finally and confirms the system’sfunctions. Secondly, this paper introduces the hardware design of cell voltageacquisition module, current measurement module, temperature measurementmodule, output and input of switching value module, CAN field-bus and so on.Thirdly, this paper introduces how to transplant μC/OS-II operating system onMC9S12XEP100and achieve J1939protocol on LabVIEW and Freescalemicrocontroller, then illustrates the way to insure high stability of system.Finally, this paper introduces battery management system test platform whichis developed by my Mentor’s research group. Then BMS is tested in differenttemperature. And this paper processes experimental data to achieve measuring errorof state parameters. Experimental result shows that the BMS can insuremeasurement accuracy in wide temperature range in this paper, and it has reliablefunction of fault diagnosis.