Research on dynamic impedance characteristics of hybrid vehicle battery

Traction batteries have been widely applied as the main powerplant for hybrid vehicles running in high power fluctuations. Based on the hybrid vehicle traction batteries, this paper described the batteries´ dynamic impedance characteristics and the influencing factors in a wide frequency range by piecewise time-frequency analysis. Some of the effects are related to the operation regime of the battery, such as battery aging, cycling current size and state of charge etc. Others are related to the structure of the battery and the rection internal the battery, such as the effect of diffusion and polarization effect at low frequency, the skin effect at high frequency. This paper analyzed the role each factor played for the battery impedance and the frequency bond that they make function. It can be helpful to battery state evaluation by analysis the dynamic characteristics. Moreover, EMI responses of power battery were predicted as spreading path for EMI in electric vehicles.