The Simulation of Ni-MH Battery Based on Optimized Thevenin Model

摘要

Ni-MH battery modeling and simulation is an important prerequisite for the study of battery characteristics and SOC estimation, so the establishment of accurate models on the battery itself and electric vehicle has important significance. The open circuit voltage is an important parameter of the battery modeling, which directly affects the accuracy of the battery model. Battery in the charge and discharge, the open circuit voltage is not the same, which is unfavorable to the modeling of the battery. So, based on the dynamic hysteresis characteristic of the open-circuit voltage of Ni-MH battery, the selection of Open-circuit voltage is optimized on the basis of the Thevenin simulation model, and the simulation model mainly optimizes the relationship between the open circuit voltage and the historical charge-discharge current direction. This paper using Hybrid Pulse Power Characterization(HPPC) test on Ni-MH power battery and Recursive Least Square method(RLS) for model parameter identification. Using Simulink to build classical Thevenin model and the optimized Thevenin model and then simulate with the input of variable current on the model. The simulation results show that the optimization model can better reflect the battery characteristics for the actual working condition of the electric vehicle and it has higher precision.