Design and optimization of bilayer structure in metal foam flow field for proton exchange membrane fuel cell

The balance between water discharge and mass transfer within metal foam flow field is vital for elevating the performance of proton exchange membrane fuel cell (PEMFC). To obtain an improved balance, this work designs a novel bilayer structure with two types of PPI (pore per inch) for metal foam flow field. Experimental and numerical results confirmed that arranging a metal foam featuring a smaller PPI in the layer 1 near the membrane electrode assembly (MEA) and a larger PPI in the layer 2 away from the MEA is beneficial to enhance the output performance. The excellent PPI combination for balancing mass transfer and water discharge involves utilizing a 50 PPI metal foam for the layer 1 and 110 PPI metal foam for the layer 2. Compared to conventional metal foam with 50 PPI, metal foam flow field with excellent PPI combination showcases a 11.2 % increase in water discharge and a 13.2 % boost in mass transfer, leading to a notable 23.5 % performance enhancement. Similarly, compared to conventional metal foam with 110 PPI, there is a 7.3 % decrease in mass transfer but a significant 29.5 % increases in water discharge, leading to a 15.2 % performance improvement.