An Adaptive Input Voltage Current-Balanced Analog Frontend System for Multiple Cell Li-ion Battery Electrochemical Impedance Monitoring

This paper proposes a dual-mode AFE system that supports both voltage and electrochemical impedance spectroscopy (EIS) monitoring for multiple cell Li-ion batteries. The proposed current-balanced IA adapts the common mode voltage of the selected cell by taking the same voltage from the same cell, enabling multiple cell monitoring with minimum current. The system also includes a DC-servo loop cancelling the DC component from the AC voltage excited by a current generator. To the best of the author’s knowledge, it is the first BMS AFE system supporting multiple cell EIS monitoring, providing better SoC/SoH estimation and safety for Li-ion batteries.