Proposing a Steady Heat Transfer Model to Predict the Temperature Rise of the Cathode’s Gas Diffusion Layer Induced by Catalytic Combustion in the PEMFCs

In this paper, a steady one-dimensional heat transfer model is proposed to predict the rise in the gas diffusion layer (GDL) of the cathode caused by the catalytic combustion of a mixture of hydrogen and air in a polymer electrolyte membrane fuel cell (PEMFC). Relative humidity (RH) cycling tests using hydrogen gas and air were conducted on a PEMFC embedded membrane NRE211 at the current density of 0 (i.e. open circuit voltage (OCV)), 0.05, and 0.3 Acm−2. After every 200 RH cycles, catalytic combustion was analyzed during OCV measurement using the thermal imaging method, employing a high-transmittance glass on the cathode side. Hotspots created due to combustion were successfully captured, with a maximum temperature rise of approximately 16 °C compared to the operating temperature of 80 °C. The heat transfer model predicts the GDL’s temperature rise fairly well and indicates that the combustion heat is predominantly transferred to the hydrogen stream due to the high convective heat transfer coefficient. During OCV measurements, the membrane temperature is increased but remains well below its auto-ignition temperature of 300 °C. However, the formation of pinholes in the scanning electron microscope images at the current density of 0 Acm−2 revealed the instant occurrence of accidental combustion during the RH cycling test when the infrared camera was not employed.