Abstract:

High-temperature proton exchange membrane fuel cells (HT-PEMFC) operate at about 160℃ and have the advantages of better electrochemical reaction kinetics, simpler hydrothermal management and higher CO tolerance than conventional low-temperature cells. However, upon the increase of operating temperature, the fast start-up of HT-PEMFC becomes one of the important challenges that restrict its application promotion. In current work, a preheat start-up method using a flat plate heat pipe (FHP) for a HT-PEMFC reactor with a rated power of 500W was attempted. An experimental system was designed and built to evaluate this method in terms of preheating time, temperature distribution, and heat transfer distribution. The experimental results showed that increasing the heating power significantly reduced the preheating time from 3000s at 500W to 980s at 1500W. However, it also caused a deterioration of the temperature uniformity, with a maximum temperature difference of about 28℃ in the vertical direction at 500W increased to 80℃ at 1500W. In addition, the temperature difference in the horizontal direction increased with the heating power, especially in the area close to the heat source, up to 15.7℃, which would undoubtedly accelerate the mechanical failure of the proton exchange membrane. In practice, a higher heating power should be selected to reduce the start-up time but not affecting the cell operating life too much.

Key words: fuel cells, heat transfer, hydrogen, measurement, thermal management, flat heat pipe

摘要：

高温质子交换膜燃料电池（HT-PEMFC）运行温度约160℃，较传统低温电池具有更佳的电化学反应动力学、更简单的水热管理和更高的CO耐受性等优势。但运行温度提高，如何实现HT-PEMFC的快速预热启动成为制约其应用推广的重要挑战之一。当前工作中，针对一个额定功率为500W的HT-PEMFC电堆，尝试利用一种平板热管（FHP）对该电堆进行预热启动。设计搭建了实验装置，从预热时间、温度分布、传热量分布等方面对这一方法进行评估。实验结果表明，提高加热功率可以显著缩短预热时间，500W时预热耗时3000s，1500W时则仅需980s；但同时也造成温度均匀性出现恶化，500W时竖直方向最大温差约28℃，1500W时该温差则达到了80℃。此外，水平方向的温差也随加热功率的提高而增加，且越靠近热源的区域越明显，最高达15.7℃，这无疑会加速质子交换膜的机械失效。实际中，应在不过多影响电池运行寿命的前提下，提高加热功率以缩短启动时间。

关键词: 燃料电池, 传热, 氢, 测量, 热管理, 平板热管