Some issues on performance analysis of fuel cells in thermodynamic point of view

In order to develop a new fuel cell and/or to enhance fuel cell performance, it is very important to understand clearly what the real performance of a fuel cell is. However, some important issues for the assessment of a fuel cell performance still require additional considerations. For example, the performance of a fuel cell is generally described based on an isothermal condition in spite of the non-uniform cell temperature distributions under real operating conditions. For this purpose, a formulation for the performance of a fuel cell operating at an isentropic condition (e.g., non-uniform cell temperature) is introduced in this study and compared with a reversible isothermal case (e.g., uniform cell temperature). Also, it is necessary to reveal the real difference in the performance of a fuel cell and a heat engine. Understanding of the purpose of the hybridization of a fuel cell with a heat engine is another important issue. In the present study, issues related to the performance of a fuel cell are considered from a thermodynamic point of view.