Derivation of an equivalent electrical circuit model for degradation mechanisms in high temperature pem fuel cells in performance estimation

This paper presents the development of an equivalent electrical circuit model that represents the characteristics of a high temperature PEM fuel cell under various fault mechanisms. The three main degradation mechanisms that can reduce long term and short term performance are investigated and the specific electrochemical parameters that are affected are identified. A semi-empirical modelling approach based on captured experimental data is used to model the degradation mechanisms in order to reduce complexity. In particular, the effect of ripple current from the power electronics that accelerates degradation of the specific model parameters is discussed. The mechanism is also included in the model in order to increase functionality. Each voltage loss component and the associated degradation phenomena are equated to a circuit element and the final circuit model is presented. The simulated results are compared to experimental data to determine accuracy. The model is able to estimate performance loss based on operating time and conditions allowing for life cycle estimation and system optimization.