Study On Powertrain Control Strategy Of Battery Electric Vehicle Based On The Cycle Life Of Power Battery

As it has the advantages of zero emissions and zero pollution,battery electric vehicle?BEV?is currently one of the main development direction of new energy vehicles.However,the problem that the cycle life of the power battery is short restricts the running performance and the popularization and application of electric vehicles.Therefore,in order to improve the cycle life of power battery,in this paper,a typical BEV is taken as the research object and the control strategy of its power system based on the cycle life of power battery is studied.Firstly,in this paper,the working principle of the lithium iron phosphate power batter y?LiFePO₄ Power Battery?and the factors affecting the cycle life are analyzed,and then the cycle performance of a LiFePO₄ Power Battery under different operating conditions is studied via the electrochemical performance experiment.Afterwards,a multi factor prediction model for the cycle life of LiFePO₄ Power Battery?multi factor prediction model for short?is established by means of multiple nonlinear regression,and in order to study the effects of different factors on the battery cycle life,the sensitivity of the model is discussed.O n this basis,the cycle life of battery pack of BEV is predicted and analyzed using the multi factor prediction model,according to the principle of electric vehicle.Then,with a typical BEV as the object,experiments of BEV under different driving cycles is carried out.The demand output power of BEV and the relationship between discharge rate and cycle life of lithium iron phosphate battery is obtained.On this basis,an optimal design method of the acceleration curve based on the cycle life of the battery of electric vehicle and the control strategy of the electric vehicle power system based on the optimal acceleration curve are developed.Afterwards,in the reference of NEDC driving cycle,the optimal acceleration curves based on the cycle life of the battery of electric vehicle are designed and the control strategy of electric vehicle power system based on optimal acceleration curve are established.Then,the control and simulation model of power system of electric vehicle based on the cycle life of its battery are established via using the vehicle simulation and analysis software i.e.AVL Cruise and matrix analysis software i.e.MATLAB/Simulink,and the control strategy of power system of electric vehicle based on the cycle life of battery is simulated and analyzedFinally,in order to verify the feasibility of the control strategy proposed in this paper,a real vehicle experiment of a typical BEV was carried out by using the dynamometer,and the relationship between the different control strategies under driving conditions and the cycle life of iron phosphate lithium battery is analyzed.