가스확산층의 다공도 분포 변화와 비균일 촉매 공급이 PEM 연료전지 성능에 미치는 영향

Abstract

Gas diffusion layer (GDL) is an important component of a PEM fuel cell to take part in the interplay of the transport of different species. It has been found that GDL contains different porosity under land and under channel areas because of compression pressure during the assembly. The liquid water generated at the cathode side increases this reduction of porosity by blocking the pores. This variation in porosity reduces the reactants consumption at the catalyst layer especially under land area of bipolar plate and is a major cause of non-uniform current density in the catalyst layer. In order to implement such kind of phenomenon numerically, positional variation in porosity has been used by dividing the whole GDL into small number of volumes using commercial code CFD-ACE+. Catalyst layer has also been divided both horizontally and vertically to implement non-uniform catalyst loading. The results show the phenomenon in the right way but do not exactly match the reference results.