质子交换膜燃料电池“微电流恢复性能”的机理与激发条件的研究

It is already discovered and confirmed that the performance of proton exchange membrane fuel cell recovered after operating on the micro-current condition between ready mode to idle condition by our project team. In order to reveal the recovery mechanism, to master and use of its excitation condition, we will focus on the research of the fuel cell membrane electrode assenbly (MEA) that affect directly its performance. .This paper focuses on the rules of changes in active area of catalyst, impedance, hydrogen crossover and double layer capacitance of the MEA, and the changes in performance uniformity of the MEAs before and after the long-operating of the micro-current condition, and focuses on the mechanism of combining voltage and current, and the influence of humidity and presure of the intake gas. This study emphasized the scientific issue of the influencing factors, the mechanism of action and the applicable range of conditions about the fuel cell "recovery". It is innovative that using our group's new research results about fule cell MEA status measurement method（constant current charge test method） to this program of the mechanism of fuel cell "recovery" phenomenon. .The achievements of this program will reveal clearly the fuel cell recovery mechanism and the scientific conditions of the "recovery" occured, and then make a contribution to the fuel cell theory and technology, and supply method to prolong lifretime of automotive fuel cells. It's predicted that the research will product no less than 4 papers indexed by SCI and EI.

前期发现和证实在燃料电池系统从待机到怠速的工况盲区存在微电流运行使性能回升的现象，为揭示这种性能恢复现象的发生机理，掌握和利用其激发条件，将围绕燃料电池膜电极组件开展研究。 .重点研究微电流工况长时间运行前后，燃料电池膜电极的催化剂活性面积、阻抗、氢渗透率、双电层电容、各片膜电极一致性等的变化规律，研究操作电流和端电压的耦合机制，研究进气湿度和压力的影响规律。拟解决的科学问题是燃料电池性能恢复的激发因素、作用机制和条件范围。主要创新点是利用本团队新研究完成的燃料电池堆多片膜电极多参数同步检测方法（恒流充电测试法），首次对燃料电池性能恢复现象开展机理研究。.本项目的研究，将揭示出燃料电池性能恢复的内在机理，准确把握实现性能恢复的科学条件，从而丰富燃料电池理论、发展燃料电池技术，为解决汽车燃料电池寿命不足的重大问题做出贡献。预期可发表至少4篇被SCI、EI双收录论文。

在本项目研究中，我们讨论了微电流活化对燃料电池性能恢复的影响。在第一部分中，单体电池在微电流工况下活化20小时。不同活化阶段的膜电极参数通过恒电流法测量，包括电化学活性面积，氢渗透电流，欧姆电阻和双电层电容。从机理上解释了这些参数对燃料电池性能恢复的影响。第二部分中，构建燃料电池模型，研究膜内平均水含量的分布和质子传导率来分析燃料电池性能恢复的关键因素。结果表明，较大的催化剂活性面积和较低的氢渗透电流会导致较大的开路电压；欧姆电阻的降低是燃料电池性能改善的重要原因；在微电流工况条件下，膜内水含量和质子传导率较大，膜内水分布更均匀;质子交换膜在微电流条件中表现出较小的降解。本研究解释了一种新的燃料电池恢复机理；分析了此机理的原因。揭示了膜电极参数和膜内水含量对燃料电池性能的显著影响，为延长燃料电池的使用寿命提供了新的途径。