“…In other words, the energy balance becomes a specification of the temperature. While most models still treat the membrane in this fashion, some have started to include nonisothermal effects and behavior [46,47,65,71,73,79,89,102,105,111,[123][124][125]. Those models that are nonisothermal along the gas channel but assume that the fuel-cell sandwich remains isothermal are not discussed in this section since the membrane is essentially taken to be isothermal [9,66,67,76].…”