质子交换膜燃料电池多物理场耦合跨尺度数值建模及水气管理研究

Polymer electrolyte membrane (PEM) fuel cells are highly promising clean energy devices as power sources of new energy vehicles. The inaccurate modeling of two-phase flow of PEM fuel cells due to the insufficient understanding of the multi-phase and multi-physics-coupled transfer mechanism in the porous electrodes and the significant decrement in the fuel cell performance caused by the electrode water flooding under high current density are two prominent problems in PEM fuel cell community. To solve these problems, the following aspects about PEM fuel cells are studied: 1) By using the galvanic cell apparatus, microfluidic approach, electrochemical impedance spectroscopy and lattice boltzmann method, the mechanism of gas diffusion, liquid water transfer, proton conductivity and electrochemical reaction in the porous electrodes are investigated and the influence factors are revealed, and then the modified and general models of the mentioned transport diffusivity can be established; 2) A 3D two-phase fuel cell numerical model based on the actual transport diffusivity in the porous mediums of PEM fuel cells is developed, which can be used in accurate prediction of the transfer properties in porous electrodes; 3) The traditional flow-field configurations are numerically and experimentally optimized with sub-channels to improve uniform distribution of the liquid water and gas in fuel cells, and then the fuel cell performance and lifetime can be effectively enhanced. Through the above studies, we hope to enrich the basic theory and provide direction for the design of actual PEM fuel cells.

质子交换膜燃料电池作为最具发展潜力的清洁能源技术之一，被视为新能源汽车的最终动力装置。针对燃料电池多孔电极内多相和多物理场耦合传输机理认识不够清楚造成的电池数值模型可靠性不足及高电流密度下电极水淹导致电池性能骤降两方面问题，本项目开展如下研究：1）利用宏观原电池原理测量法、微流控技术和电化学阻抗法与介观格子玻尔兹曼方法跨尺度研究并揭示电池多孔电极内气体扩散、液态水渗透传输、质子传导及电化学反应等耦合传输机理，获得多孔电极关键传输参数真实和普适数学描述；2）基于上述关键参数建立的本构关系，构建可精确预测多孔电极传输特性的燃料电池三维两相全电池数值模型；3）开展电池双极板流场分流设计的数值与实验研究，获得改善电池内水气分布均衡性的最佳流场设计与操作参数方案，有效提升电池性能并延长其使用寿命。通过上述研究，期望推动燃料电池基础理论的发展，并为实际电池的开发设计提供坚实的理论参考依据。

质子交换膜燃料电池被认为是第三次能源革命的核心驱动力之一。针对燃料电池多孔电极内多相和多物理场耦合传输机理认识不够清楚和高电流密度下电极水淹问题；本项目采用多尺度数值模拟方法和微流控技术等实验手段揭示了燃料电池多孔膜电极内气液两相扩散传输机理，完善和发展了三维两相全电池多场耦合输运模型，实现了电流、反应气体、温度和液态水等多物理量迁移和分布的同时准确预测，为燃料电池多场输运迁移分布及电池整体性能预测提供了更准确的模拟仿真工具；探明了燃料电池双极板肋下“水淹”、传质恶化及水气失衡机制，开发出了多种新型流场形式强化肋下排水和传质的水气管理新理念，实现了燃料电池的水管理，为燃料电池低高性能运行提供了理论设计指导；此外，构建了流道和扩散层表面液滴动力学行为的动态润湿模型，丰富和发展了液滴在固体表面的输运机理，为大电流燃料电池高效除水、传质强化和功率密度提升提供了解决方案。发表期刊论文 8 篇，其中第一作者及第一标注SCI 收录论文7篇，申请国家发明专利2项并获得授权；发表国内外学术会议论文7篇。完成了任务书的既定目标。