Semi-Empirical Equation of PEMFC Considering Operation Temperature

Abstract

The characteristic of a proton exchange membrane fuel cell is shown by the relationship between its output voltage and current. The output cell voltage determines the activation loss, ohmic loss, and concentration loss. Studying these losses is important to understand their effect of the reduction factor of the output of the fuel cell. One method of calculating these losses is by the curve-fitting using a semi-empirical equation. This method is useful for quickly predicting the performance. In previous studies, the fuel cell temperature has been assumed to be steady. However, the operation temperature of the fuel cell is not constant in the real fuel cell systems, such as residential and vehicular fuel-cell stacks. Therefore, it is difficult to separate the different types of losses on a polarization curve. In this study, we propose a new semi-empirical equation considering the fuel cell's operation temperature. Through thermodynamic, mechanistic, and electrochemical modeling, we express the initial voltage, activation loss, ohmic loss, and the concentration loss. We compare the fitting parameters of the proposed equation with those of equations proposed in previous studies. We also study the effects of operating temperature and cathode gas on the parameters that influence the performance.