Influence of crack formation at the catalyst layer and membrane interface on the performance of PEMFC

Temperature and humidity cycling during frequent startup-shutdown of proton exchange membrane (PEM) fuel cell (PEMFC) can lead to crack formation in the catalyst layer (CL) or even at the interface between the CL and PEM, decreasing the effective activation area and degrading the fuel cell performance. This study develops a two-dimensional PEMFC model using COMSOL software which is well validated, and investigates the effect of different lengths and positions of CL/PEM interface crack (delamination) on the mass transport and performance of PEMFC. The results show that both the crack length and position have significant influence on the cell performance, especially at high current density. The presence of crack leads to an uneven distribution of cell current density, and the performance of the cell decreases with the increase of the crack length due to decreased activation area. The crack near the inlet has the greatest adverse impact on the cell performance, compared to other positions near the outlet or in the middle of the rib. Compared to the cell without cracks, the decrement in current density is 5.05%, 9.55% and 15.52%, respectively, for the crack in the middle of the rib, near the outlet and near the inlet.