Low-Complexity Electrochemical-Impedance Spectroscopy for Battery Monitoring

This article shows how to realize a low-complexity system for electrochemical impedance spectroscopy aimed at monitoring the state of charge and state-of-health of a rechargeable battery. In particular, it is shown how to acquire the current and voltage signals used for estimating the battery impedance by means of simple one-bit analog-to-digital converters, e.g., comparators. Architectural and system-level requirements are considered. A detailed procedure is presented that describes how to process one-bit data to recover the full-resolution signals needed to estimate the battery impedance. Theoretical and experimental results are presented to illustrate and validate the one-bit electrochemical impedance spectroscopy framework. Experimental results using a 3.7 V, 2600 mAh lithium-ion cell rechargeable battery show that its impedance is estimated using one-bit data, with a maximum magnitude error less than 3%, and a phase error of 2.4 degrees.