Droplets dynamics theory and micro-flow field experiments of improving self-humidifying feature and maximum power density in fuel cells

Abstract Micro-flow field is a preeminent stratagem for improving Proton exchange membrane fuel cells (PEMFC) output performance. Elucidating the droplet dynamics behavior in the micro-channel and its impact on water management is essential. This work has investigated that, for the same radius droplets, the maximum driving pressure difference of droplets will increase by 560% approximately in micro-channel due to the matched characteristic dimension through theoretical analysis based on the fluid mechanics model. The micro-flow field ( 0.5 m m × 0.5 m m channel) in PEMFC can promote the maximum power density by about 48% compared to the normal-flow field ( 1 m m × 1 m m channel) in PEMFC by experiments under the same operating conditions and membrane electrode assembly. Simultaneously, PEMFC with the micro-flow field can obtain the most excellent performance without humidifying the air. Its self-humidification characteristic makes it possible to cancel the humidification equipment in the auxiliary system in the future.