In Situ Temperature Distribution Measurement in an Operating Polymer Electrolyte Fuel Cell

Abstract

The temperature distribution in a polymer electrolyte fuel cell (PEFC) is of critical importance to the water balance, as well as to other kinetic and transport phenomena that are known to be functionally dependent on temperature. However, direct measurement of localized temperature is difficult, due to the two-phase nature of flow in the gas channels and the small through-plane dimensions of a typical electrolyte. To circumvent these difficulties, an array of microthermocouples was embedded directly between two 25 μm thick Nation™ electrolyte sheets of a membrane electrode assembly. The embedded array was used to measure electrolyte temperature as a function of current and fuel cell flow channel location. For the fuel cell tested with natural convective cooling, a temperature increase in the electrolyte of as much as 15°C is observed for current densities of 1 A/cm2.