A novel flow reversal concept for improved thermal management in polymer electrolyte fuel cell stacks

In a polymer electrolyte fuel cell (PEFC) stack equipped with a forced-convection open-cathode manifold, significant temperature gradients can develop from the inlet to the outlet due to the incoming cool air heating up as it passes through the cathode flow fields. In this study, we propose a new conceptual design for effective cooling of a PEFC stack by periodically reversing the flow direction of the air used for convective cooling. The impact of the flow reversal scheme is studied via mathematical model of the three-dimensional two-phase flow and associated conservation equations of mass, species, momentum, charge, and energy. The model includes both the stack and the fans used for cooling air supply. The model results indicate that the temperature, water and current density distributions become more uniform and produce reduction in the highest temperature reached in the stack which also enhances stack performance relative to the unidirectional coolant flow case.

► We propose a novel flow reversal concept for improved thermal management in an open-cathode fuel cell.
► Flow reversal results in a more uniform temperature, membrane water content and current density distribution.
► It is beneficial to avoid thermal degradation of the membrane and avoid localized bending stresses.