气体扩散层内部交叉流动对PEMFC水跨膜输运影响分析  

Influence of cross-flow within the gas diffusion layer on transmembrane water transport in proton exchange membrane fuel cell

作　　者：范馨远 刘永峰 裴普成[2] 张璐 FAN Xinyuan;LIU Yongfeng;PEI Pucheng;ZHANG Lu(School of Mechanical-Electronic and Vehicle Engineering,Beijing University of Civil Engineering and Architecture,Beijing Engineering Research Center of Monitoring for Construction Safety,Beijing 102627,China;Tsinghua University,State Key Laboratory of Intelligent Green Vehicle and Mobility,Beijing 100084,China)

机构地区：[1]北京建筑大学机电与车辆工程学院,北京市建筑安全监测工程技术研究中心,北京102627 [2]清华大学,智能绿色车辆与交通全国重点实验室,北京100084

出　　处：《储能科学与技术》2024年第11期3772-3783,共12页Energy Storage Science and Technology

基　　金：国家自然科学基金(52376091);汽车安全与节能国家重点实验室开放基金(KFY2218);北京市建筑安全监测工程技术研究中心研究基金(BJC2020K005);北京建筑大学培育项目专项资金(X24030)。

摘　　要：质子交换膜燃料电池(PEMFC)内部相邻流道间的压差产生了交叉流动,其作用于气体扩散层(GDL)内部,有利于改善传质,增强液态水的排出,对反应物供给有着至关重要的影响。为理解交叉流动对反应物分布及水的跨膜输运过程的影响,本文建立了一个耦合交叉流动与水跨膜输运过程的三维两相模型,并通过搭建的测试系统对单电池进行测试以验证模型,分析了影响交叉流动的因素、路径和对水跨膜输运的影响。结果表明,交叉流动迫使气体从高压流道角落进入GDL流向相邻低压流道,并在下一流道的角落处流出。交叉流动速度随相邻流道间压差增大而增大,与阳极相比,阴极的压降更高,导致阴极的交叉流动速度高于阳极。阴极最大交叉流动速度(0.13 m/s)靠近流道出口,而阳极最大交叉流动速度(0.05 m/s)靠近流道入口。交叉流动使流道拐角处具有更大的以电渗拖拽为主的跨膜水通量,还促进了脊下聚集的水的清除从而影响了以浓差扩散为主的跨膜水通量。气流对入口区域的吹扫降低了入口区域的膜态水含量,出口区域的高浓差扩散提高了出口区域的膜态水含量。The pressure difference between adjacent channels in a proton exchange membrane fuel cell(PEMFC)induces cross-flow within the gas diffusion layer(GDL),which enhances mass transport,improves liquid water removal,and supports reactant supply.To investigate the effect of cross-flow on reactant distribution and transmembrane water transport,this study developed a three-dimensional two-phase model that incorporates cross-flow dynamics with water transport processes.The model was validated through single-cell testing using a purpose-built experimental setup.The analysis focused on cross-flow pathways and their impact on water transmembrane transport.Results indicate that cross-flow drives gas entry into the GDL from the high-pressure channel corners,directs it toward adjacent low-pressure channels,and exits at the subsequent channel corners.Cross-flow velocity increases with the pressure difference between neighboring channels,with the cathode exhibiting higher cross-flow velocities due to greater pressure drops compared to the anode.The highest cathode cross-flow velocity(0.13 m/s)was recorded near the channel outlet,whereas the anode's peak velocity(0.05 m/s)occurred near the channel inlet.Cross-flow enhances the electro-osmotic drag water flux at channel corners and aids in removing water accumulated beneath the ribs,thereby affecting the concentration-driven transmembrane water flux.Airflow at the inlet reduces membrane water content,while elevated concentration gradients at the outlet increase membrane water content in that region.

关 键 词：质子交换膜燃料电池 气体扩散层 交叉流动 跨膜水通量 

分 类 号：TM911[电气工程—电力电子与电力传动]