Online Condition Monitoring of Sealed Lead Acid & Lithium Nickel-Cobalt-Manganese Oxide Batteries using Broadband Impedance Spectroscopy

Electrochemical Impedance Spectroscopy (EIS) has been widely utilized for the study of the dynamics and condition monitoring of batteries. EIS plots are fitted to an equivalent circuit that models the physicochemical processes of the batteries. Moreover, to accurately estimate the state of the batteries, Kramers-Kronig relation of linearity, stability and causality is to be adhered to. The drawbacks of EIS measurements are that it is applied offline, requires very expensive Frequency Response Analyzers (FRA) and suffers from lengthy measurement time. In this study, different broadband signals that shorten measurement time are compared for online condition monitoring of lead acid and lithium-ion batteries. The adoption of a novel technique - Chirp Broadband Signal Excitation (CBSE) is proposed for online condition monitoring purposes, as it has the advantage of being faster and precise at the most important frequency decade of the impedance spectrum of batteries.