Yang Liu, Sun Z Y, Zhang Guang-Meng, Li Zeng-Shan, Ren Ke-Xuan
Hydrogen Energy and Space Propulsion Laboratory (HESPL), School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing, 100044, China.
Beijing Long March Tianmin High-Tech Co., Ltd., Beijing, 100076, China.
Heliyon. 2024 Jun 6;10(12):e32501. doi: 10.1016/j.heliyon.2024.e32501. eCollection 2024 Jun 30.
The gas diffusion layer (GDL), as the bridge to reactants and electrons in PEMFC, is a carbon-based porous component and would be deformed under compression to induce changes in the distributions of reactants and the corresponding performances of PEMFC; therefore, unmasking the impacts of assembly pressure on the distribution of the reactants in GDL is significant to improve the performance of PEMFC. In the present article, the structural response of GDL to assembly pressure was first studied; the variations in transport properties of GDL and the reactant distributions induced by assembly pressure were then discussed; the impacts on the dynamic performances of PEMFC were finally investigated. From the results, assembly pressure was found to have different effects on the regions of GDL under the rib and channel, significant gaps in GDL porosity and/or GDL permeability existed near the rib/channel transition region to worsen the inhomogeneity of reactants. Suffering assembly pressure, the distribution of current density became uneven, and the current density near the rib-channel border seriously rose to the aggravated risk of MEA thermal damage. Furthermore, the power density at specific efficiencies was raised under certain assembly pressures, which meant suitable assembly pressure(s) existed for better output performances of PEMFC.
气体扩散层（GDL）作为质子交换膜燃料电池（PEMFC）中反应物与电子的传导桥梁，是一种碳基多孔组件，在压缩状态下会发生变形，进而导致反应物分布以及PEMFC相应性能的变化；因此，揭示装配压力对GDL中反应物分布的影响，对于提升PEMFC的性能具有重要意义。在本文中，首先研究了GDL对装配压力的结构响应；接着探讨了装配压力引起的GDL传输特性变化以及反应物分布情况；最后研究了其对PEMFC动态性能的影响。结果表明，装配压力对肋条和流道下方的GDL区域有不同影响，在肋条/流道过渡区域附近，GDL孔隙率和/或GDL渗透率存在显著差异，加剧了反应物分布的不均匀性。在装配压力作用下，电流密度分布变得不均匀，肋条 - 流道边界附近的电流密度严重升高，增加了膜电极组件（MEA）热损伤的风险。此外，在一定装配压力下，特定效率下的功率密度有所提高，这意味着存在合适的装配压力可使PEMFC获得更好的输出性能。
