Abstract: In order to effectively implement the energy management strategy of the whole vehicle and achieve safe and optimal battery management system,a battery management system is designed according to the structural characteristics of electric vehicles,and the response principle of control nodes of the whole vehicle during the highvoltage power on and off is analyzed.Then,a control strategy of the normal power on and off as well as of the emergency power off is proposed for the whole vehicle,and the fault level of the proposed battery management system is defined.Moreover,fault threshold tables are designed to realize the control strategy under fault condition.Finally,the Stateflow /Simulink software is adopted to perform the control logic modeling and simulation of power on and off for the whole vehicle as well as of the fault of battery management system,and the proposed control strategy is verified by the actual vehicle tests under static and NEDC conditions.The simulation and experimental results show that dealing with high-voltage power on in insulation error and high-voltage power off in HVIL error accords well with the control logic and dealing with high-voltage power off in insulation error ensures the safety of high-voltage,so that the control logic of power on and power off is more conducive to the energy control of the whole vehicle.

Key words: electric vehicle, power on and power off, battery management system, fault, control strategy, simulation and experiment