加长加宽的PEMFC电堆应力分布一致性仿真与优化

Simulation and Optimization of Stress Distribution Uniformity for Enlarged PEMFC Stacks

质子交换膜燃料电池可以通过扩大电堆的活性区域反应面积来获得更高的功率,但电堆反应面积扩大后,容易导致膜电极应力分布的不均匀性增加,从而引起燃料电池电化学性能的下降.为此,本研究设计了4种不同结构尺寸的燃料电池电堆,结合等效刚度模型法和有限元软件,分析了扩大反应面积的电堆结构对膜电极应力分布均匀性的影响,并进一步优化电堆内钢带的安装位置,以提升电堆内部接触压力分布均匀性.研究结果表明,膜电极接触压力分布的均匀性对反应区域宽度的变化较为敏感,当活性区域尺寸加宽,电堆内部活性区域的平均应力标准差增加了23.2%.而当活性区域加长,或同时加长和加宽时,相应增加一根捆扎钢带使电堆内部活性区域的平均应力标准差分别减小了8.6%和8.7%,表明适当增加捆扎钢带的数量可以提高电堆内部接触压力分布的均匀性.此外,钢带位置优化结果显示,电堆外侧钢带越靠近端板侧面时,电堆内部活性区域的应力分布越均匀.

Proton exchange membrane fuel cells(PEMFCs) can achieve higher power by expanding the reaction area of the stack active area.However,for stacks with enlarged reaction areas,there is a tendency for increased nonuniformity in the distribution of membrane electrode assembly(MEA) stress,leading to a decline in the electrochemical performance of fuel cells.In this study,four different structural sizes of PEMFC stacks were designed.Using a combination of the equivalent stiffness model and finite element software,the impact of stack structures with expanded reaction areas on the uniformity of stress distribution of the MEA was analyzed.Furthermore,the installation position of steel belts within the stack was optimized to enhance the uniformity of internal contact pressure distribution.The research results indicate that the uniformity of MEA contact pressure distribution is particularly sensitive to changes in the reaction area width.When the size of the active area is widened,the standard deviation of the average stress within the stack's internal active region increases by 23.2%.Conversely,when the active area is lengthened,or both lengthened and widened simultaneously,adding a corresponding bundled steel belt reduces the standard deviation of the average stress within the stack's internal active area by 8.6% and 8.7%,respectively.This suggests that appropriately increasing the number of bundled steel belts can improve the uniformity of contact pressure distribution within the stack.Additionally,optimization results for belt positioning show that the more the outer steel belt is positioned closer to the end plate side,the more uniform the stress distribution within the stack's internal active region.