Reinforcement of proton‐exchange membrane fuel cell performance through a novel flow field design with auxiliary channels and a hole array

Abstract

A novel flow field was designed by deploying auxiliary channels inside the partially hollow ribs and drilling a series of arrayed holes on the auxiliary channels. This novel design rationally utilizes the ribs of the current collector and improves the volumetric efficiency of the parallel channels, leading to improved cell performance and homogeneity of current distribution. A three‐dimensional, two‐phase flow model was developed to analyze the influence of a variety of parameters on the oxygen and water saturation profiles, cell performance, and current uniformity. It was found that the combination of auxiliary channels and hole array provides an extra pathway for reactant transport and water removal. A reasonable optimization of the flow field geometry, for example, the hole size, the area ratio of arrayed holes and auxiliary channels, nonuniform distribution of arrayed holes, could further improve the cell performance and current uniformity at an extremely low pressure drop.

Improvement of under‐the‐rib oxygen concentration and water removal in proton exchange membrane fuel cells through three‐dimensional metal printed novel flow fields

“…27 In other words, the arrayed holes mitigate the water flooding under the Experimental condition: flow field area 8 cm 2 , RH of anode 50% and cathode 100%, temperature 70 C, pressure 1 atm rib while increase the ohmic resistance for electron transport. 28 The optimal length ratio of the auxiliary and main channels is a trade-off between the raise of ohmic resistance and the improvement of local oxygen concentration and water removal, which could be supported and explained by the modeling results of our recently published paper. 28 Since the numerical analysis of novel parallel flow fields have been performed in our last paper, in the following section, only the numerical results of novel serpentine flow fields are shown to avoid repetition.…”

“…28 The optimal length ratio of the auxiliary and main channels is a trade-off between the raise of ohmic resistance and the improvement of local oxygen concentration and water removal, which could be supported and explained by the modeling results of our recently published paper. 28 Since the numerical analysis of novel parallel flow fields have been performed in our last paper, in the following section, only the numerical results of novel serpentine flow fields are shown to avoid repetition. 28 The profiles of liquid water saturation inside the cathode GDLs field is approximately 0.62 A cm À2 , which is improved to 0.64, 0.74, and 0.73 A cm À2 when 2, 4, and 6 auxiliary channels are implemented.…”

“…In other words, the arrayed holes mitigate the water flooding under the rib while increase the ohmic resistance for electron transport 28 . The optimal length ratio of the auxiliary and main channels is a trade‐off between the raise of ohmic resistance and the improvement of local oxygen concentration and water removal, which could be supported and explained by the modeling results of our recently published paper 28 …”

“…The increase in interfacial electrical resistance (few orders of magnitude higher than the resistance of the plates) may lead to the electron transport through the contact area of GDL and ribs as the rate limiting process 27 . In other words, the arrayed holes mitigate the water flooding under the rib while increase the ohmic resistance for electron transport 28 . The optimal length ratio of the auxiliary and main channels is a trade‐off between the raise of ohmic resistance and the improvement of local oxygen concentration and water removal, which could be supported and explained by the modeling results of our recently published paper 28 …”

“…Since the numerical analysis of novel parallel flow fields have been performed in our last paper, in the following section, only the numerical results of novel serpentine flow fields are shown to avoid repetition 28 …”