Inconsistent responses of cells on operating conditions in a 5 kW proton exchange membrane fuel cell stack

The cell inconsistency investigation for large-scale proton exchange membrane fuel (PEMFC) stacks is significant. In this paper, the between fault cells and normal ones investigated in a 5 kW stack with 30 of active area 312 cm2. Considering typical operating conditions, temperature hydrogen/air stoichiometry are to discuss effects on inconsistency. As comprehensive indexes, voltage performance, polarization curve, electrochemical impedance spectrum (EIS) presented evaluate above experiments. To enhance EIS resolution, distribution relaxation times (DRT) applied extract characteristic frequency points from ranged 0.5 Hz 10 kHz. conclusion, sensitive conditions poor performance larger resistance compared cells. Furthermore, DRT can well quantify impedances produced by oxygen diffusion (fault ~ 4.0 m? 0.3 1.0 m?) reduction reaction 0.7 1.5 0.6 m?), respectively. Meanwhile, strongly relates conditions. Moreover, damaged structure electrode assemblies further validates scanning electron microscopy.