Transforming adverse effect into beneficial outcome: A design strategy leveraging non-uniform flow for enhanced performance of PEM fuel cells

Non-uniform flow in Proton Exchange Membrane (PEM) fuel cells with parallel flow fields can enhance performance, whereas a targeted regulation strategy has not been established. Hence, a systematic numerical investigation is conducted in this work. First, the impacts of channel dimensions on flow uniformity and cell performance are examined, accompanied by a sensitivity analysis. The core lies in the transverse cross-rib flow in the porous medium induced by non-uniform flow distribution. Building on this, a design strategy combining channel refinement and active area scale-up is proposed to facilitate the capability accumulation and release of this flow pattern, with the expectation of mitigating the inherently restricted reactant transport beneath ribs and thereby strengthening the electrochemical reaction. Second, this strategy is applied in the Manifold configuration. The current density improves from 1.49 % below to 13.49 % above that in the Uniform configuration. Flow non-uniformity rises, and the transverse cross-rib flow intensity increases markedly from 1.99 to 1078.85. The adverse effect of non-uniform flow is successfully transformed into a beneficial outcome. Third, the applicability of the proposed strategy is validated under different operational and geometric conditions, with the Manifold configuration consistently outperforming the Uniform configuration by more than 10 %. Furthermore, system efficiency and SWOT analyses are conducted to assess its prospects.