Title : Mass transfer in porous media and the technique of water-heat management for proton exchange membrane fuel cells
Abstract:
The proton exchange membrane fuel cell plays a significant role in energy conservation and emission reduction. Towards the commercialization, this fuel cell still faces the difficulties on low-temperature stat-up and shunt-down, long-time operation without any flooding or drying-out, etc, which should be solved through the investigation on water-heat management and especially the refined mass transfer in porous media. In this speech, the gas and liquid water transportation through gas channel, gas diffusion layer (GDL), especially the catalyst layer will be introduced, which features the catalyst modelling using meso-scale structure meshing and the key finding that the two-phase flow pressure drop of the channel/ GDL experiences two ramp-ups where the one related to the well operation phase that no flooding or drying-out occurs. Then, the liquid water amount at gas channel, GDL and CL is estimated respectively and the strategy for operation management through regulating fuel cell temperature, air flow rate, air inlet pressure is proposed to obtain the best performance based on the above-mentioned water estimation method. Finally, the thermal management and fuel cell control methods are presented featuring the leading parameter estimation for the dynamic system for a more accurate model and resulting the better proof at the whole power-range. The results could be a better guidance for the -30 ℃ start-up without external heating and shunt-down strategy making. Meanwhile, the catalyst layer modelling is beneficial to the application of online and real-time estimation for water amount estimation, secondary reaction assessment.
