Effect of cathode flow field configuration on air-breathing proton exchange membrane fuel cell

Air-breathing proton exchange membrane fuel cells (AB-PEMFCs) have been known to reduce the cost, complexity, noise, volume, and weight of fuel cells and can enhance their reliability. However, AB-PEMFCs still have some crucial issues such as the depletion of local oxygen concentration adjacent to the cathode in the absence of convection and hydrogen starvation at the anode side caused by the improper mass and water management in the dead-end mode. To manage mass and water efficiently, the effect of the opening ratio of the cathode opening geometry was investigated by considering the effects of the reaction area and contact resistance. When the opening ratio of the air flow field increased, the cell performance improved. However, at the high opening ratio of 72%, even though the voltage did not drop as quickly at high current densities as that at a low opening ratio, the cell performance was lower than that at the low opening ratio. And the slit-type fuel cells showed better performance by comparing the performances of the slit and square types of the cathode opening geometry. By introducing mesoscale channels on the flow field surface of the cathode, the formation of water droplets on the gas diffusion layer was minimized considerably.