Guidelines for Evaluation of Error Structure for Impedance Response of Polymer Electrolyte Membrane (PEM) Fuel Cells

Abstract

Impedance spectroscopy provides the opportunity for in-situ identification and quantification of physical processes in any electrochemical system. However, the impedance response is influenced by instrumental artifacts and non-stationary behavior. General guidelines, based on use of a measurement model, are outlined for estimation of an error structure of impedance measurements. The methodology is applied to estimate error in the impedance response of a Polymer Electrolyte Membrane (PEM) fuel cell. The analysis was used to show that low-frequency inductive loops in impedance response of the fuel cell were, in some cases, fully self consistent, and could therefore be attributed to processes occurring in the fuel cell. The error analysis was also used to improve the sensitivity of the impedance to onset of flooding in the fuel cell.