Abstract Flow fields play an important role in performance enhancement of a Proton Exchange Membrane Fuel Cells (PEMFCs). However, the weak mass transport ability of the conventional parallel flow field seriously affects the cell performance, especially at high current density. In this work, a series of S-shaped flow fields are designed and experimentally verified. The effects of key design parameters, such as the S radius (R) and the S length (H), on the cell performance are investigated in detail by recording the polarization curves under different cathode relative humidity (RH) levels and stoichiometric ratios. The results indicate that the small R and large H are beneficial to the promotion of cell performance owing to the increased turbulence and decreased liquid water content in the cell, which is also proved by the electrochemical impedance spectroscopy (EIS). However, the pressure drop significantly increases at the same time, which affects the output ability of the cell. Considering the net output capacity and the processing processing possibility, the cell with the S radius of 17.4 mm and the S length of 40 mm exhibited the peak power density of 1.02 W cm−2, with 15% higher than the CPFF (870 W cm−2).

中文翻译：

---

质子交换膜燃料电池中S形流场的实验研究

摘要 流场在质子交换膜燃料电池 (PEMFC) 的性能增强中起着重要作用。然而，传统平行流场较弱的传质能力严重影响了电池性能，尤其是在高电流密度下。在这项工作中，设计了一系列 S 形流场并进行了实验验证。通过记录不同阴极相对湿度 (RH) 水平和化学计量比下的极化曲线，详细研究了关键设计参数，如 S 半径 (R) 和 S 长度 (H) 对电池性能的影响。结果表明，小 R 和大 H 有利于提高电池性能，因为增加了湍流，降低了电池中的液态水含量，电化学阻抗谱（EIS）也证明了这一点。但同时压降明显增大，影响电池的输出能力。考虑到净输出容量和加工处理的可能性，S半径为17.4 mm和S长度为40 mm的电池表现出1.02 W cm-2的峰值功率密度，比CPFF（870 W cm-2）高15% −2)。