Investigation of stress and water distribution in Membrane Electrode Assembly (MEA) during fuel cell operation

摘要

Investigation into the durability of fuel cells is a challenging issue due to the large number of parameters affecting membrane electrode assembly (MEA) integrity. The mechanical stresses induced in the membrane due to swelling associated with water absorption play an important role in the long-term failure of the MEA. Thus, the stresses and the water distribution in the MEA are coupled. To better understand the relationship between mechanical stresses and water absorption, we introduce a numerical model to simultaneously determine the swelling-induced stresses and the water distribution in the MEA under various cell operating conditions. Preliminary results suggest that open-circuit voltage (OCV) operations lead to the most severe environment for the mechanical response, whereas under current load, the stresses and the permanent deformation are on average lower and localized at the cathode side of the MEA. The results suggest that the mechanical behavior of the MEA must be taken into account in the investigations of MEA degradation to establish a complete understanding on the failure mechanisms and durability.