Numerical analysis on water transport in alkaline anion exchange membrane fuel cells

Abstract

We present an isothermal, one-dimensional, steady-state model for an alkaline anion exchange membrane fuel cell (AAEMFC), in which the conducting ions (OH-) move from the cathode to the anode. While water is produced at the anode, it is consumed at the cathode along with oxygen. The water transport in the membrane comprises water flux by the electro-osmotic drag and the diffusive water flux because of the gradient of water concentration across the membrane. The present model is validated with the experimental data in the literature and the water transport in AAEMFC is discussed. By performing numerical simulations of four cases of humidity conditions (dry or fully humidified conditions for each anode and cathode), it is reconfirmed theoretically that anode humidification is more essential to secure good AAEMFC performance. In addition, water transport through the gas diffusion layers of anode and cathode as well as the membrane is examined to provide fundamental information about water management in the AAEMFC operations.