Broadband identification of battery electrical impedance for HEV

In recent years, Li-ion batteries have been proposed as an essential element for hybrid electrical vehicles (HEV) and electrical vehicles (EV). In such applications, the most possible accurate estimation of the battery states is needed to optimize its operation. Accordingly, battery electrical impedance is known to be able to provide useful states information. Though that electrical impedance spectroscopy has firmly established itself as one of the most informative investigation method especially because of its accuracy, it cannot be easily implemented in embedded systems. In this paper, broadband excitation signals, frequently used in system identification applications, are proposed to perform impedance measurements on a battery cell. Moreover, spectral coherence is an advanced parameter estimated in order to determine the frequency bands where the transfer function of the system is accurately identified. We propose in this study to test and compare the identification performances of such signals for the broadband monitoring of a battery.