作　　者： ; ; ; ;

机构地区： 清华大学机械工程学院汽车安全与节能国家重点实验室

出　　处： 《农业机械学报》 2014年第7期340-346,共7页

摘　　要： 通过观察阳极气体压力降对一个两片的质子交换膜燃料电池堆进行水淹预警的研究发现,其在水淹过程中阳极气体压力降具有'两级台阶'的变化特征。结合流道内水积聚过程的研究成果以及电压的变化特点,可以将水淹过程分为良好期、湿润期、过渡期和水淹期4个阶段。对比实验表明电流和温度对于两级台阶的相对幅度影响不大,气体压力和阳极过量系数对台阶相对幅度有较显著的影响。提高气体压力和增大阳极过量系数可以提高PEMFC抵抗水淹的能力,但增大阳极过量系数则会造成氢气浪费。调整电池堆工作温度是一种有效的水淹自愈手段,通过调整温度可以使PEMFC工作在'微湿未淹'的状态下。阳极脉冲排气或增大阳极气体过量系数则可作为PEMFC严重水淹时的辅助处理措施。 Flooding diagnosis is the key issue of PEM fuel cell. Flooding prediction through hydrogen pressure drop is investigated in this study on a two-piece PEMFC stack. Pressure drop is a key parameter to diagnose water content of PEM fuel cell. The hydrogen pressure drop is more suitable for flooding prediction because it can reflect not only the content but also the water harm on PEM fuel cell. Furthermore, the ideal hydrogen pressure drop is calculated through the operation conditions. Flooding experiments are organized and a two-level characteristic on hydrogen pressure drop is observed. At first, the actual hydrogen pressure drop keeps steady nearly the same as the ideal value, and the voltage is pretty high and constant. Next, the hydrogen pressure drop rises gradually because of the appearance of water droplets. Then, the hydrogen pressure drop performs the second steady level because the water droplets form a liquid film. Finally, the hydrogen pressure drop rises quickly and the voltage drops rapidly as the formation of slug flow. Combining with the visualization results of water droplet accumulation in channels and the tendency of hydrogen pressure drop and voltage, the flooding process can be divided into four continuous periods, which are proper period, humid period, transitional period and flooding period. The growth rate of the hydrogen pressure drop is defined and four groups of flooding experiments are completed, in which the effects of current, temperature, pressure and hydrogen stoichiometry can be discussed. Experiment results show that current and temperature influence little on the growth rate of two levels, while the effect of pressure and hydrogen stoiehiometry is remarkable. Increasing the gas pressure can improve the ability for anti-flooding in PEMFC, increasing the hydrogen stoichiometry will waste hydrogen as consideration. The hydrogen purge can take a part for a while in the flooding period to prevent the fuel cell from falling into total flooding, while it does not change the operation con

关 键 词： 质子交换膜燃料电池 水淹预警 阳极气体压力降

领　　域： [电气工程]