Multi-physics model for regenerative PEM fuel cell energy storage

Electrochemical storage (ECES) systems are expected to become increasingly important and widespread in the coming years, with the expansion of renewable energy sources, smart grids and electrical vehicles. Special advantages can be provided by those ECESs which can be independently sized in power and stored energy. Some of the most promising technologies of this type are redox flow batteries and fuel cells combined to electrolyzers. Both these technologies are under extensive R&D programs, aimed at improving their performance. As regards the latter, regenerative fuel cells (R-FCs) provide both charge and discharge functions in the same device. This paper presents a unified model able to describe both these operation modes of R-FCs of the PEM (polymer electrolyte membrane) type (R-PEMFC). The model takes into account the dependence of the electrical quantities and parameters on the major physical-chemical variables and can be used to address structural and operational optimizations.