To clarify the mechanism of coupling phenomena such as heat, mass and electric charge transfer in a single-cell polymer electrolyte fuel cell (PEFC), we have measured in-plane temperature distribution in a single-cell PEFC by thermograph under power generation. We have investigated the influence of gas flow rate at inlet and gas channel pitch of separator on in-plane temperature distribution and power generation performance. As a result, the higher temperature region is observed near the outlet of cell when the stoichiometric ratio of gas flow rate is set over 1.00 due to the convection heat transfer by excess oxygen flow in gas channel at the cathode. When the stoichiometric ratio of gas flow rate is set at 1.00, in-plane temperature distribution becomes uniform and high power generation performance is obtained. Total voltage is increased and temperature in observation area is decreased with decreasing the gas channel pitch of separator irrespective of gas flow rate.
