A new equivalent circuit model of Ni-MH battery pack based on the subspace identification method

Battery model is the foundation for estimating the state of the battery energy, and it is also an important basis for the simulation of the electric vehicle´s dynamic performance. Therefore, an accurate and suitable battery model is of important practical significance on the development of electric vehicles. In this paper, according to the dynamic characteristics of Ni-MH battery during the charge and discharge process, subspace identification method was adopted to set up a state-space model of the battery. Through the analysis of the model output voltage, a battery equivalent circuit model was built, and the model parameters could be identified by the least square method. Finally, the accuracy of the battery model was verified by the experiment.