Power Battery Model Analysis And Its Fast Charge And Discharge Strategy Study

Due to the fog haze weather occurs frequently recently throughout China, whichseriously affect the People’s Daily lives and also take people’s attention to motor vehicleemissions again, and the auto industry has to take the responsibility for the energyconservation and emission reduction. As an economic and feasible abatement options,the production and development of electric vehicles has aroused people’s attention，therefore, the research of power battery is great significance which is one of the corecomponents for electric vehicles.The paper enumerates the existing battery models, and then expounds thecharacteristics of various models and their advantages and disadvantages; finally selecta first order RC battery model as the research object. The author uses the data fromcharging and discharging experiments to identify the battery model parameters; the ohminternal resistance of battery is analyzed and lists the curve that the ohm internalresistance changes with SOC (State of Charge), then gives the curves of the modelparameters changes with the battery SOC. Then using least square method for thepolarization resistance and capacitance of the battery model for nonlinear curve fitting,get the model parameters with the battery SOC change curve. The author puts forwardan improved mathematical model based on the existing relationship of the open circuitvoltage and the battery SOC, and uses the nonlinear curve fitting method to get itsparameters, and compares the effect with other models is feasible. The paper uses theextended kalman filter method to estimate the SOC of the battery by using the modelparameters and the method of parameter online identification.According to the theory of fast charging of the battery on the basis of the researchmodel of battery charge and discharge characteristics and the comparison of several fastcharging method, put forward an integrated charging method on the basis of thethree-stage charging method, combined with the constant current charging and pulsecharging method. This approach to trickle charge the battery first, and big currentconstant current fast charge, then the battery terminal voltage pulse fast charging afterreach a certain stage, and finally to float charge battery. Paper combines battery model parameters and their characteristics analysis results, mainly analysis the fast chargephase pulse whose self-learning correction based on the charging parameters and thecombination of battery performance model and experimental data to analyze theself-learning module’s prior knowledge and rule base. Finally the three stage charging,pulse charging and an integrated charging method in charging and discharging platformwhich built in MATLAB based on xPCTarget system’s data real-time acquisition andanalysis, through the comparison of experimental results obtained in this papercomprehensive charging method is better than the other two kinds of charging method.