A review on flow field design for proton exchange membrane fuel cells: Challenges to increase the active area for MW applications

As a reaction to climate change, several countries have set decarbonization plans, in which hydrogen and fuel cells play a central role. Due to its distinctive features, PEMFC is considered a promising technology to decarbonise heavy-duty transport including applications requiring MW-power. Hence, development of high-power stacks, i.e., stacks with significantly increased flow field area is required. This implies possible issues such as uneven distribution of reactants, heat and water management. Consequently, adequate flow field designs are crucial to tackle these issues and ensure stable PEMFC operation at high power. Flow fields have been investigated across PEMFC literature. However, considerations how to develop an effective flow field with a large active area are missing. This work aims to fill this gap by, (i) listing challenges to develop a flow field with an active area >1000 cm2 (ii) analysing most powerful PEMFC stacks on the market and (iii) reviewing the literature regarding flow field, while providing a critical analysis of the information gathered and identifying promising patterns and optimization routes. The aim is to encourage further investigation on scalable flow field designs and push PEMFC closer towards MW-applications. It was found that, despite the unprecedented scale of the active area, most of the issues identified can be addressed through adequate flow field design. Moreover, PEMFC stacks available on the marked still fall short of the MW-range, delivering typically around 100 kW. Based on literature several factors affecting flow field design are identified. Eventually, a specific flow field for MW-applications was proposed.