Flow-field design for commercial size PEFC with high plate area utilization

A 200 cm2 flow field for 1 kW stack with a flow field area/plate area ratio of about 0.8 was designed using a proprietary methodology based on a software for dimensioning and coupled to CFD analysis. A mass flow rate ( . passing through the backing of the electrode of about 0.4 for the reference 50 cm2 Jab cell was determined, and assuming that closer values ensure a comparable performance, anode and cathode flow fields of 200 cm2 with the same . value of 0.4 were designed and realized . Home made multi-layers electrodes with a total Pt loading of 0.5 mg cm-2 in the catalyst layer, 4.5 mg cm-2 of SAB carbon supported on carbon cloth for diffusion layer were used for tests. Same electrodes were used for anode and cathode side and the final MEA was realized by hot pressing, at 20 kg cm-2 and 130°C for 3 min. , the electrodes with a Nation® 115 membrane. To verify the influence of cell design on the cell performance the polarization curves have been recorded and a comparison with the 50cm2 single-cell reference was performed. Working at 80°C, 1.5 bar of absolute pressure and a stoichiometric ratio of 1.5/2 for H2 and air respectively at 1A cm-2 , with a 50cm2 single-cell reference a maximum power density of 345 mW cm-2 was obtained in comparison with a power density of 326 mW cm-2 with 200cm2 single-cell. The results have shown that the used methodology for the cell area scale-up is adequate to obtain commercial size cells without considerable performance losses.