The Study On The Optimization Of Structure And Operational Condition Of Small Hydrogen-Air Fuel Cell

Fuel cell is an equipment of power generation, which has high power density andenergy conversion efficiency and produces no pollution to the environment. Protonexchange membrane fuel cell(PEMFC) has the advantage of low working temperature,fast startup and variable scale, the research of fuel cell, especially PEMFC, is rapidlydeveloping around the world. In terms of small hydrogen-air PEMFC, it has been onthe eve of commercialization.In this paper, we introduce the working principle of PEMFC, and summarize itsresearch actuality in the past years. Using small hydrogen-air PEMFC as our object ofstudy, in the basic of designing a simply structure of small hydrogen-air PEMFC, westudy the influence in the performance of fuel cell stack of optimization of operationalcondition and innovation in the structure of fuel cell stack.First of all, we have studied the affection on the output performance of fuel cellstack of these three factors: the addition of dispersion plates, the way of fuel gasintake and the way of fuel gas outtake. The main component are: testing the effect ofgas intake with single hole,double holes and three holes; adding different dispersionplates on the both sides of fuel gas intake and outtake and testing the performance;bleeding the end gas intermittently with a valve in the exit and testing the effect ofdifferent outtake frequency. The result shows that intake with double holes,addingdispersion plates and 10s as the outtake frequency is benefit to improve theperformance of small Hydrogen-air PEMFC stack.Secondly, this paper researches the impact of the activation procedure to theperformance of the MEA. We have designed a new method of circular activation byourselves. To do the research of activating the MEA, we use the new method andnatural activation method with constant current in two same fuel cell stack,respectively. The result shows that with the new method the fuel cell stack can reachto its optimal performance in a shorter time.Finally, we test the optimum performance of the cell stack based on the optimaloperational conditions and activation method. The result shows that, by forcedactivation at varied current and working at optimal operational conditions, the singlecell voltages can be uniformly distributed, and the influence on the performance of cell stack is small when we reduce the H2 flow at a big range. This illustrates that theeffect of activation on MEAis good, and the use factor of H2 has also been improvedgreatly. The highest power density is up to 48W when the current is 6A; and the cellstack can work steadilyat long time.