Optimization of assembly clamping pressure on performance of proton-exchange membrane fuel cells

The compression induced by the assembly of proton-exchange membrane (PEM) fuel cells causes partial deformation of the gas-diffusion layers (GDLs) and affects the characteristics of the porous media and, consequently, influences the performance of PEM fuel cells. The objective of the present study is: (1) to develop a three-dimensional model to investigate the effect of assembly clamping pressure on the GDL properties and thus on the performance of PEM fuel cells, and (2) to determine the optimum clamping pressures when the cell is operated under different operating voltages. The optimum clamping pressures under different operating voltages are explored by using a global searching method, namely, the simultaneous perturbation stochastic algorithm (SPSA) method. The simulation results indicate that a clamping pressure of 1 or 1.5 MPa improves the fuel cell performance when the cell is operated under high operating voltages, and causes the cell performance to decrease when it is operated under low-voltage conditions. The optimum clamping pressures increase when the operating voltage increases.