In situ measurement of temperature distribution across a proton exchange membrane fuel cell

The temperature distribution across a proton exchange membrane fuel cell was measured by inserting micro-thermocouples between layers such as a gas diffusion layer and membrane electrode assembly. Under steady-state operation, the cathode catalyst layer had the maximum temperature. The activation overpotential at the cathode catalyst layer served as the main heat source, resulting in the maximum temperature at the cathode catalyst layer. The temperature at the cathode catalyst layer just after the load current was interrupted had the minimum temperature. This is thought to be caused by water evaporation from the cathode catalyst layer, where liquid water accumulates during operation.