In situ EIS as a Diagnostic Tool for Performance Analysis of Fuel Cells and Batteries in Automotive Applications

This article analyzes the main issues of the hydrogen fuel cell performance in relation to a possible application in the transportation sector. The hybridization concept between fuel cell generator and electric energy storage systems to be applied in fuel cell power train design is discussed evidencing the role of the different sub-systems in dynamic conditions typical of automotive applications. Cell durability is individuated as a critical issue limiting the practical application of fuel cell technology in the transportation sector. A literature review about the various degradation mechanisms of fuel cell electrochemical interfaces is presented, and the EIS technique is described as an useful tool to investigate these deactivation causes. Electrochemical impedance spectroscopy results, related to the analysis of a hydrogen fuel cell stack used as a generator in a fuel cell power train, are discussed with the aim to evidence the main degradation causes of a fuel cell operating in dynamic conditions.