Study on Transient Response of a Unit Proton Exchange Membrane Fuel Cell with an Aged Gas Diffusion Layer

내구성능저하된 기체확산층이 고분자전해질 연료전지의 과도응답성능에 미치는 영향 연구

The gas diffusion layer is the key component of the proton exchange membrane fuel cell because it directly affect to the mass transport mechanism and dynamic behavior of the cell. In this study, the effects of GDL aging on the transient response of the PEM fuel cell is systematically investigated using current step transient response analysis under different stoichiometric ratios and humidity conditions. With GDLs aged by the accelerated stress test, the effects of hydrophobicity and structural changes due to carbon loss in the GDL on the transient response of PEM fuel cells are determined. The degraded GDLs that had uneven hydrophobicity distributions cause local water flooding inside the GDL and induce lower and unstable voltage responses after load changes.