Generalized scaling-up approach based on Buckingham theorem for Polymer Electrolyte Membrane Fuel Cells impedance simulation

The present paper describes a generalized scaling-up methodology applied to Polymer Electrolyte Membrane Fuel Cells. The use of proper scaling-up algorithms can reduce testing costs within fuel cell manufacturing process by evaluating full stack performance (i.e., impedance behavior) from a single cell/short stack measurement. The algorithm here described relies on a former approach developed by the authors and consists in a generalized methodology combining information measured on single cell and simple physical models (e.g., charge transfer resistance expressed through Tafel equation). A robust technique for the identification of cell reference operational state, such as membrane hydration, from non-scaled data is also introduced. Connection between charge transfer resistance and limiting current is established through diffusion losses modelling. Single cell internal states are estimated by means of inverse models function of numerical intercepts of measured cell spectrum. Stack impedance estimation is then performed through stack internal states assumptions. To prove the consistency and robustness of the proposed methodology, literature data used to design and test the former algorithm version are here considered for algorithm testing and verification.