Mass transfer and water management in proton exchange membrane fuel cells with a composite foam-rib flow field

TL;DR

This paper introduces a composite foam-rib flow field for proton exchange membrane fuel cells, enhancing oxygen transfer and water removal, leading to improved power density and current capacity without extra energy costs.

Contribution

It proposes and simulates a novel composite foam-rib flow field, optimizing key parameters to significantly boost fuel cell performance over conventional designs.

Findings

Peak power density increased by 5.20%.

Limiting current density increased by 22.68%.

Improved oxygen transfer and water management capabilities.

Abstract

Mass transfer capability of reactants and hydrothermal management is important for the performance and durability of proton exchange membrane fuel cells. In the conventional rib flow field, the oxygen transport is affected by the accumulation of under-rib liquid water which causes excessive concentration loss and limits cell performance. To improve the cell performance, a composite foam-rib flow field structure is proposed by combining the metal foam flow field and the conventional rib flow field. The proposed design is simulated by using a three-dimensional homogeneous non-isothermal numerical model. The results show that the composite foam-rib flow field, by improving the oxygen transfer and water removal capabilities under the ribs, can improve the oxygen concentration and current density without increasing the pumping power, thus improving the cell performance under different conditions. The key parameters of the composite foam-rib flow field are optimized. With the optimal metal foam filling ratio of 0.75 and porosity of 0.85, the peak power density and the limiting current density for the composite foam-rib flow field are higher than the conventional rib flow field by 5.20% and 22.68%.