Effect of Operating Conditions on the Water Transport Phenomena at the Cathode of Polymer Electrolyte Membrane Fuel Cell

Water management is very important for polymer electrolyte membrane fuel cell because the fuel cell performance is decreased by flooding phenomena generated by liquid water in the cathode channels. In addition, the proton conductivity and water transport of membrane could become different by hydration contents of membrane. This study is observed water transport phenomena of cathode channels with a polymer electrolyte membrane fuel cell according to various operating conditions. In order to obtain the water images, the transparent fuel cell consists of polycarbonate window of the cathode end plate and gold coated stainless steel as the flow field and current collector of the cathode. To investigate the effects of operating conditions on the water transport, experiments were conducted under various operating conditions such as cell temperature, cathode flow rate and cathode backpressure. As operating time elapsed, it is observed that the water droplet formation, growth, coalescence and removal occurred in the cathode channel. It can be known that the high cathode flow rate prevents water flooding by removal of water in the cathode flow channel. Also, the quantity of water droplet was increased by the high cathode backpressure.