薄型流场对燃料电池性能影响的交流阻抗谱法研究

Study on Effects of Flow Field Depth on Performance of PEMFC by AC Impedance Spectroscopy

利用交流阻抗测试法对采用薄型流场板的氢气/空气质子交换膜燃料电池单电池进行了表征。实验结果表明,阴极侧流场深度的减小对燃料电池性能的影响几乎可以忽略,而阳极侧流场深度对燃料电池性能的影响则相对较大。对具备不同形式与深度的阳极流场的单电池进行交流阻抗测试和分析,并辅以极化曲线测试,发现阳极侧流场深度从1.0mm的单路蛇形流场降低至0.4mm后,燃料电池在大电流密度下的性能受到影响;当电流密度大于1200mA/cm2时,电池的浓差极化进一步加剧,导致电池的最大输出功率略有下降。尽管如此,由于极板总体厚度的减小,电池的体积比功率密度仍得到很大程度的提高。

AC impedance spectroscopy was adopted to characterize the H2/Air PEMFC with thin polar plates. The results show that the influences of the cathode flow field depth are minor and can be ignored meanwhile the performances of PEMFCs decreases with the thinning of the anode flow fields. AC impedance spectroscopy testing of five single cells with different thin anode polar plates were then conducted, as well as polarization curve tested. Apparent performance dropping can be found at higher current density when the anode flow field depth decreases from lmm to 0.4ram. At the current density of 1200mA/cm2, the concentration polarization is further exacerbated,which results in the decrease of maximum output power. The volumetric specific power of the fuel cell is still promoted greatly due to the thinning of the polar plate.