Dynamic Characteristic Of Cathode Oxygen Transport Of PEMFC

Proton Exchange Membrane Fuel Cell has a wide range of applications including small and medium-sized electronics products and automobile. Science researchers and merchants regard PEMFC as one of the most potential clean energy and will be huge promising. Predecessors have make lots of work about model and numerical simulation in PEMFC, while most of them still focus on the characteristics of steady state and the study of dynamic performance is in an extreme early development at present.This paper builds a2-D isothermal and uniform mathematical model in double phase flow which based on continuity equation, ideal gas and Fick’s laws to describe the dynamic characteristic of oxygen transport in cathode of PEMFC. The instantaneous simulating results make clear that oxygen distribution has related to saturation in gas diffusion layer and catalyst layer of cathode. Saturation is large corresponding to oxygen mole fraction is small. Controllable factors including inlet relative humidity of cathode, current density and operating temperature have obvious influences on oxygen distribution in cathode.Simulating results of dynamic model show that when current density changes, oxygen mole fraction has an obvious modification. And activation over-potential is relative to oxygen mole fraction in gas diffusion layer and catalyst layer. The work finds activation over-potential increases with improvement of current density and the cell voltage drops. The oxygen dynamic behavior is seriously affected by step current density, inlet relative humidity and air stoichiometry. In this paper, the last chapter simulates the performance of booting in PEMFC and describes the influences from inlet relative humidity and load current density. Moreover, it discusses the capability of booting under three operating temperature respectively with saturated humidifying in cathode.This work only researches dynamic transportation of oxygen and the effects on the performance of cell, but operating pressure and temperature impacts unobvious on cell performance. It can be seen that simulating results are highly fitted to experimental data under same operating conditions.