Rib-Channel Optimization for Flowfield Design of PEM Fuel Cells

Channel design affects ohmic losses, pressure drop and transport losses associated with PEM fuel cells. The objective of this work is to optimally design flow-fields using a combination of modeling tools and limited experiments to improve performance. More specifically, we focus on optimizing rib-channel dimensions and for this purpose we have developed a detailed and distributed steady-state model of a small section of a PEM fuel cell. Two-Dimensional gas and charge transport equations are solved simultaneously, while water transport is modeled using a response-surface obtained from higher fidelity simulations. Limited experimental data are used to tune the model. The model is then employed to determine optimal-rib channel dimensions subject to machining constraints. We present results for different gas-diffusion layer thicknesses and properties. We also demonstrate that it is possible to obtain improvements in power density by optimizing rib-channel dimensions.