Optimization Of PEMFC Performance Considering Water Transport

The PEMFC is one kind of appliance that makes hydrogen and oxygen reaction converts chemical energy into electrical energy. This paper firstly introduces the cell’s working principles, advantages and disadvantages, categories, development and application, and the important components. The effect of operating conditions on the fuel cell performance is introduced, and the cell performance is optimized considering water transfer.The effect of operating conditions on gas-liquid two-phase water transfer and the cell performance is studied. The results show that when the temperature raises, the activity of the catalyst increases, the battery of the reaction rate is accelerated, gas mass transfer rate also increases, but too much water is took away from cell because of high temperature. Higher operating pressure increase the gas inlet concentration and the reaction’s rate of PEMFC, and it can increase the amount of water, but it also could lead to water flooding; Higher stoichiometry increases the flow rate of gas inlet, but it will take away a lot of water; Higher relative humidity increases the amount of water and the proton conduction rate, but too much water can block the catalytic channel, catalytic activity is also reduced, the performance of cell will be lowered.This study deeply analyzes the optimization of the fuel cell parameters considering water transport. The results show that the optimized temperature have little effect on the cell performance with the increase of film thickness. At larger film thickness(Hm = 125 mm), the optimized pressure is bigger(about 0.72), and the optimized stoichiometry increases at low current density(about 4.3) and decreases at large current density(about 2.2).The reaction rate increases and the activation polarization reduces with the increase of exchange current density. The results show that the optimized temperature and pressure have little influence on the cell’s performance with the increase of exchange current density, at the same time the smaller stoichiometry can meet the needs of the reaction(about 3).The concentration polarization decreases and cell performance improves with the increase of limiting current density. The results show that the optimized temperature and pressure changes little with the increase of limiting current density, but stoichiometry can be reduced appropriately. When the limiting current density is larger(iL=2.02 A/cm2), a smaller stoichiometry(about 2.5)can be chosen.