Pre-bent Flow-Field Plates for Enhanced Performance in Flexible Polymer Electrolyte Membrane Fuel Cells in Curved Shape

This article reports on a flexible polymer electrolyte membrane fuel cell (PEMFC) with a pre-bent flow field. The performances in the flat and bent positions were lower and higher, respectively than that of the traditional flexible fuel cells. The low performance in the flat position was attributed to the void space induced incomplete contact at the interface of the membrane electrode assembly (MEA) and flow-field plates, which resulted in poor performance due to the high ohmic resistance (5.85 Ω cm2) and faradaic resistance (4.17 Ω cm2). However, when bending stress was applied to the MEA, a decreased ohmic resistance (0.954 Ω cm2), faradaic resistance (0.737 Ω cm2), and an enhanced power density (88.7 mW/cm2) were observed because of the improved interfacial contact property between the MEA and the flow-field plates from the increased compressive stress. These experimental results were further analyzed and visualized with aid of the finite element analysis. Despite the relatively low performance in the flat shape, the proposed pre-bent design of the flexible PEMFC possesses promising applicability especially in flexible electronics where the curved shapes are highly required.