A Novel Design of Wave-Like PEMFC Stack with Undulate MEAs and Perforated Bipolar Plates

Fuel cells are being pursued for a wide variety of applications due to their high theoretical efficiency and environmental friendliness [1, 2]. In particular, proton exchange membrane fuel cells (PEMFCs), because of the advantages of low temperature operation, fast start-up, system robustness and low emissions, are attractive for automotive and portable applications [3]. However, commercialisation of PEMFC technology depends on achieving high volumetric power density and specific power for a given cost, so that its characteristics compete cost-effectively with traditionally used energy conversion devices [4]. The US Department of Energy’s (DOE) 2010 technical target for automotive fuel cell power systems operating on direct hydrogen is that volumetric power density is 2,000 W L and specific power is 2,000 W kg for stack [5]. Optimisation the stack architecture and usage of low-cost lightweight material for bipolar plates are two efficient ways to improve the fuel cell power density and lower its cost simultaneously. As shown in Figure 1, conventional PEMFC stack designs have been based on planar, repetitively stacked structure that use milled or pressure-moulded plates to deliver fuel and oxidant gases to the reaction sites. Nevertheless, some new structural designs for PEMFCs have been proposed for higher power density by modifying the geometries of membrane electrode assembles (MEAs) or bipolar plates in recent years. A micro-tubular fuel cell was developed by NASA to improve the volumetric power density for portable electronic equipments [6]. The MEAs were tubular in shape which could be packed into a small case with oxygen/hydrogen cross flow. This design increased the power density because