Optimisation of air cooled, open-cathode fuel cells: Current of lowest resistance and electro-thermal performance mapping

The Hydro-electro-thermal Performance of Air-cooled, Open-cathode Polymer Electrolyte Fuel Cells: Combined Localised Current Density, Temperature and Water Mapping

“…These results confirm the conclusions from previous work based on electro-thermal profiles alone [88], which showed that the purely ohmic resistance (proxy for membrane hydration) initially drops (during self-hydration), reaches a plateau, and then increases above 60°C during the dehydration. This hydration / dehydration process has been experimentally reported for self-breathing, open-cathode fuel cells [46], and modelled [89]; but only now can the role of water be confirmed.…”

“…This corresponds to the centre of the ohmic region on the electrothermal map. It overlaps with the optimum operating zone, determined using the current of lowest resistance, introduced in previous work [88]. Gradual dehydration starts above 45 °C, with a 'dry' state reached above 60°C.…”

“…For further analysis, the localised distributions are investigated via current, temperature and water mapping as a single dataset in the hydro-electro-thermal analysis. Electro-thermal performance maps have been introduced in previous work as a novel way to display the influence of the air flow rate and current density on the voltage and temperature of fuel cell operation [88]. Including the water content provides another dimension in understanding the coupled nature of processes occurring in operational fuel cells.…”

Paradox phenomena of proton exchange membrane fuel cells operating under dead-end anode mode

“…In support of the latter, the performance of a DEA-mode fuel cell mode yielded a constant cell performance for 3  longer periods of time when supplied with pure H 2 and O 2 compared to when H 2 and air supplies were used [8]. Meyer et al [13] claimed that 50 ppm N 2 in the grade of H 2 used (BOC "zero grade" H 2 -likely to be widely used in such research work) leads to accumulation of N 2 at levels up to 2.3% in the anode of DEA PEMFCs (i.e. contributes to most of the N 2 observed in the anode).…”

“…Fuel cells operating under dead-end anode (DEA) mode is of increasing interest [2][3][4][5][6][7][8][9][10][11][12][13][14] as control systems can be significantly simplified. However, water accumulation and the N 2 crossover (cathode  anode) are issues of concern [2][3][4][5][6][7][8][9][10].…”