Water Transport in Ionomer and Ice Formation during Cold Startup with Supercooled State in PEFC
Water Transport in Ionomer and Ice Formation during Cold Startup with Supercooled State in PEFC
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PEFC 过冷状态冷启动过程中离聚物的水传输和冰的形成
DOI：
10.1149/07514.0623ecst
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
and T. Chikahisa
中科院分区：
文献类型：
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作者：
N. Wakatake;Y. Tabe;and T. Chikahisa
聚合物电解质燃料电池在接近0 ℃（如-10 ℃）的冷启动时，产生的水在冻结之前保持过冷状态，然后发生关闭，在阴极催化剂层（CL）和微孔层（MPL）之间形成冰层。据我们以前的研究估计，CL中的水传输发生在离聚物中的浓度梯度。本文通过冷启动特性测试和膜电极横截面的低温扫描电镜观察，研究了离子聚合物中水分的迁移和结冰行为。为了评估水的传输，我们测量了在过冷释放期间对应于水含量的聚合物膜电阻的变化。此外，为了改善冷启动特性，我们引入了亲水性MPL，并确认亲水性MPL使启动时间更长，直到停机，并改善冰分布。
At cold startup of polymer electrolyte fuel cells near 0 C like–10 C, the produced water remains as supercooled state before it freezes, and then the shutdown occurs with ice layer formation between the cathode catalyst layer (CL) and micro-porous layer (MPL). It was estimated from our previous study that water transport in CL occurs by concentration gradient in ionomer. This study investigated the water transport in ionomer and the ice formation behavior by measurement of cold start characteristic and observation of cross-section of membrane electrode assembly by a cryo-SEM. To evaluate the water transport, we measured change in polymer membrane resistance corresponding to water content during the supercooling release. Further, to improve the cold start characteristic, we introduced a hydrophilic MPL and confirmed that the hydrophilic MPL makes the startup period until the shutdown longer, and improves the ice distribution.