Review of electrochemical impedance spectroscopy in fault diagnosis for proton exchange membrane fuel cells

Timely and efficient fault diagnosis is crucial for improving the performance, durability, and lifespan of onboard proton exchange membrane fuel cell (PEMFC) systems. Electrochemical impedance spectroscopy (EIS) provides effective information about the dynamic reaction processes, which has been widely used for fault diagnosis of electrochemical systems. However, no reviews have comprehensively summarized the recent advances of EIS in fault diagnosis for PEMFCs from the perspectives of system and onboard. Motivated by the literature gap, this review provides a state-of-the-art understanding of EIS in onboard fault diagnosis for PEMFC systems, consisting of five main parts: powerful tool, calculation methods, measurement systems, diagnosis applications, and in-depth outlook. Innovative methods for utilizing EIS in fault diagnosis for onboard PEMFC systems include fast impedance acquisition, applications of nonlinear EIS, stack-single-partitioned impedance measurement, and development of fault diagnosis algorithms. The challenges related to the fast impedance acquisition as well as fault diagnosis challenges associated with nonlinear, partitioned, and coupled characteristics of PEMFCs need to be further addressed. The aim of this review is to fill the gap, to provide a comprehensive review and fresh perspectives, and to contribute to the studies which are focus on EIS in onboard fault diagnosis for PEMFC systems.