Since the electrochemical impedance spectroscopy (EIS) is a powerful tool to estimate the state of a lithium-ion battery cell, its implementation in electric vehicles is driven forward in many research activities.

Within this context, we present results on a distributed system for single cell impedance measurements within a larger battery unit. The system is characterized by a centralized current excitation and decentralized measurements of cell voltages and current, which have to be precisely synchronized. The decentralized measurement controllers at each cell are based on a low-cost microcontroller and integrable electronic.

The decentralized impedance measurement system is designed to be used in automotive battery cells with large capacities (> 100 Ah) and very small internal resistances (<1 mOhm).