Operation characteristics of air-cooled proton exchange membrane fuel cell stacks under ambient pressure

Air-cooled proton exchange membrane fuel cells (PEMFC) simplify the traditional cooling and air supply system. Three air-cooled stacks are assembled with different cells to investigate the effect of the polytetrafluoroethylene (PTFE) content in the gas diffusion layer (GDL), air flow rate, as well as the stack temperature on the stack performance. The results show that GDL with appropriate thickness and PTFE content can optimize the stack operation performance. The effect of the cell order on its performance can be neglected. A thermal equilibrium resulting from the heat generation and loss in the stack is achieved near the ambient temperature at low current density of 150 mA cm−2. The output power increases with the increase of air flow rate. However, when the air flow rate exceed 44.7 L min−1 or the stack temperature is higher than 65 °C, the stack performance decreases.