A physics-based 1-D PEMFC model for simulating two-phase water transport in the electrode and gas diffusion media

Abstract

While significant progress in PEMFC research has been achieved in recent years, simulation of liquid water formation and transport accurately still remains a significant challenge. Under wet operating conditions, liquid water may condense in the channel, gas diffusion layer, or electrode, which introduces complicated transport phenomena. In this work, we present a physics-based, steady-state, 1-D, non-isothermal, and two-phase PEMFC model that captures the interactive nature of gas and liquid transports to simulate fuel cell performance. Limiting current experiments are employed to study both dry and wet oxygen transport resistances of Toray-H-060 carbon fiber paper with PTFE impregnation and a microporous layer. A two-phase model based on limiting current diagnostics is proposed to simulate water transport in the gas diffusion layer using tendril length to represent liquid water penetration. This newly constructed model is capable of predicting the total transport resistance under dry, transition, and wet regions. In addition, an empirical catalyst utilization model is proposed to correlate the electrode water activity with catalyst utilization. The two-phase electrode model provides key insights into the relationship between catalyst utilization and electrode flooding. The newly developed 1-D two-phase model is highly efficient in predicting PEMFC performance under a wide range of operating conditions and the empirical approach can be applied and adopted to studies with novel materials and designs.