Multicomponent Transport in Porous Electrodes of Proton Exchange Membrane Fuel Cells Using the Interdigitated Gas Distributors

Abstract

Hydrodynamics of gases in the cathode of a proton exchange membrane fuel cell that is contacted to an interdigitated gas distributor are investigated using a steady-state multicomponent transport model. The model describes the two-dimensional flow patterns and the distributions of the gaseous species in the porous electrode and predicts the current density generated at the electrode and membrane interface as a function of various operating conditions and design parameters. Results from the model show that, with the forced flow-through condition created by the interdigitated gas distributor design, the diffusion layer is greatly reduced. However, even with a much thinner diffusion layer, diffusion still plays a significant role in the transport of oxygen to the reaction surface. The results also show that the average current density generated at an air cathode increases with higher gas flow-through rates, thinner electrodes, and narrower shoulder widths between the inlet and outlet channels of the interdigitated gas distributor.

A review of performance degradation and failure modes for hydrogen-fuelled polymer electrolyte fuel cells

“…Interdigitated flow fields could be used over conventional gas distributors to improve oxygen distribution to the cathode catalyst layer and water removal by adding forced convection to gas diffusion to drive transport in the porous layers [55]. Forced convection is induced by decoupling the direct path between inlet and exit flow fields on both sides of the BPP design.…”

A polymer electrolyte membrane fuel cell model with multi-species input

“…This limitation extends to other 2D computational models where multi-component transport is included but restricted to the inclusion of oxygen, nitrogen, and water in the inlet cathode feed after humidification [6,7]. This reflects only the ideal case.…”

Gas-Phase Mass-Transfer Resistances at Polymeric Electrolyte Membrane Fuel Cells Electrodes: Theoretical Analysis on the Effectiveness of Interdigitated and Serpentine Flow Arrangements

“…The specific scopes and usefulness of this approach need a little discussion. On the one hand, specific and detailed simulation approaches of local kinetics and flow fields in PEMFC electrodes can be found in the literature [25]; our approach aims to achieve a mean kinetic expression in order to avoid the repetition of a cumbersome and time consuming calculation load for each point (or finite element) of the electrode. Therefore, the ultimate goal is to provide simple correlations to estimate Sherwood numbers (that is, mass transfer effects and limit currents) and their combination with electrochemical kinetics.…”