Fuel cell parameter analysis and constraint optimization based on Nelder-Mead simplex algorithm considering performance degradation.

An important breakthrough in improving the efficiency of fuel cell systems is the utilization of optimization algorithms to search for operational parameters. In this process, it is crucial to conduct a rational analysis of optimization variables and parameter constraints, along with the use of precision and fast-converging optimization algorithms. In this study, a detailed lumped-parameter fuel cell air supply subsystem model is established and the polarization curve of the fuel cell stack is verified experimentally. Based on which, the coupling relationships among the operational parameters are analyzed and the coupling constraints are derived through simulations. Subsequently, the constrained Nelder–Mead simplex algorithm is used to maximize the system efficiency. Finally, the changes in fuel cell operational parameter after various degrees of degradation are studied. Results show that as the current increases, the optimal oxygen excess ratio decreases, and the optimal cathode inlet pressure increases. Furthermore, the optimization results show that the optimal stack temperature is the lowest constrained temperature that satisfies humidity requirements, which further shrinks the search space of optimization algorithm and transforms a 4-variable optimization problem into a 2-variable optimization problem. Additionally, both the optimal oxygen excess ratio and optimal cathode inlet pressure increase with the increase of degradation time, with the trend becoming more pronounced. The conclusions drawn in this study can serve as guidance for subsequent fuel cell parameters optimization and the selection of operational parameters. • A lumped-parameter model for fuel cell air supply subsystem was established. • The fuel cell operating parameters' constraints were determined. • The constrained simplex method was employed to search for the optimal parameters. • Changes in the optimal parameters were analyzed at different level of degradation. [ABSTRACT FROM AUTHOR]