封装力对PEM燃料电池气体扩散层孔隙率的影响

Influence of assembly force on porosity of GDL in PEM fuel cell

质子交换膜(PEM)燃料电池中气体扩散层(GDL)的孔隙率对整个燃料电池的性能有着重要影响,而封装力是影响燃料电池GDL孔隙率的关键因素之一。采用实验和有限元模拟相结合的方法研究封装力对气体扩散层孔隙率的影响。利用压汞仪测试气体扩散层的平均孔隙率,基于有限元方法建立质子交换膜燃料电池的双极板和气体扩散层的接触模型,研究质子交换膜燃料电池中不同的封装力下气体扩散层的孔隙率变化情况。结果表明:气体扩散层孔隙率的变化沿接触中心线左右对称,接触区域孔隙率分布较为均匀,随着封装力的增加,气体扩散层孔隙率逐渐降低;而未接触区域孔隙率变化不明显。气体扩散层孔隙率有限元模拟结果与实验测试结果相吻合。

The porosity of the gas diffusion layer （GDL） in proton exchange membrane （PEM） fuel cellhas a significant effect on PEM fuel cellperformance. Assembly force was critical to the porosity of the GDL. Based on both experimental and finite element methods, the influence of assembly force on porosity of the GDL was studied. The mercury porosimeter was employed to measure the average porosity of the GDL. The contact model between bipolar plate （BPP） and GDL of the PEM fuel cellwas established, and finite element method （FEM） was used to study the variation of porosity of the GDL applied with various assembly forces. The simulated results show that the variation of porosity of the GDL was symmetrical along with the center line of the contact area. The porosity distribution in GDL was uniform at the area where GDL contacted with BPP under the applied assembly force. And the porosity of the GDL was decreased gradual y with the increase of the assembly force. However, the porosity was not change significantly at the area where GDL did not contact with BPP. The finite element analysis results were in good agreement with the experimental results in average porosity.