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Electrochemical Impedance Spectroscopy (EIS) has
gained traction as a technique apt for condition monitoring of batteries. The
drawback of EIS is that it is only applicable when the system is offline (i.e.
it must be disconnected from the load), takes a long time to complete and
requires an expensive equipment for measurement. This work aims to adapt the
EIS to serve as an in-situ measurement technique, that can be utilized for
online condition monitoring of two unique battery chemistries – lead acid and
lithium NCM. This work develops in twofold – firstly, the Chirp broadband
signal is proposed amongst a variety of other broadband signals to
significantly shorten the time required for EIS measurement. Subsequently, a power
converter that is typically used to interface a battery with the load for
current and voltage regulation functions, is utilized for online condition
monitoring of both batteries through closed loop control of the power converter
and duty-cycle perturbation. This combined approach presents a novel low-cost technique
for online condition monitoring of batteries, with the ability to complete battery
characterization in a very short time. In this regard, EIS measurement is
completed for a lead acid battery (with lowest EIS characterization frequency
of 0.1Hz) in 5 seconds and lithium NCM battery (with lowest EIS
characterization frequency of 20mHz) in 25 seconds.