Electrochemical Impedance Spectroscopy Setup based on Standard Measurement Equipment

Abstract

The approach of electrochemical impedance spectroscopy is widely used to analyze electrochemical systems such as batteries and fuel cells. The majority of commercial spectroscopes is however limited to the investigation of devices under test at laboratory scale. In this paper the development of a setup performing impedance spectroscopy of commercial lithium-ion battery cells and complete packs up to 42 V and 10S4P configuration is demonstrated which is entirely based on standard measurement equipment. Galvanostatic AC excitation of up to 5A peak-to-peak can be reached. The obtained impedance spectra qualitatively match the theoretical expectations and reference results from literature. Acquired results can be successfully fitted to a second-order Thevenin equivalent circuit model without requirement of specialized analysis software. OriginPro is used as an example for the presented setup. A similar sensitivity towards external factors such as temperature and probe contacting as it applies for commercial devices is observed. The described setup can be reproduced in most electrical laboratories with similar equipment and the application scenario is not limited to batteries. This gives access to a powerful analysis tool complementing commercial impedance spectroscopy devices by extending measurement ranges towards higher voltage and excitation current as well as lower impedance.