Study on Thermo-mechanical Coupling Characteristics of Hot Pressing on Surface Microstructures of Proton Exchange Membrane for Fuel Cells
Proton exchange membrane(PEM)is the core functional component of H+transportation at the anode and cathode of fuel cells.The traditional smooth membrane surface has issues such as poor proton transportation and small three-phase reaction interface.Constructing functional microstructures on the membrane surface is a promising strategy to develop high-performance fuel cells.To explore the thermo-mechanical coupling mechanism during the manufacturing process of micro hot embossing,the elastic-plastic and viscoelastic mechanical properties of proton exchange membranes(PEMs)under different temperatures and stresses are investigated in this study.Based on these experimental data,a viscoelastic constitutive model of PEM is constructed and demonstrated.The manufacturing mechanism and rheological behavior of PEMs during the micro hot pressing is revealed.The results show that the elastic deformation range of a PEM decreases,and the plastic deformation range extends with the increase in temperature under the same force.Meanwhile,as temperature increases,the fraction of elastic strain decreases and the fraction of viscous strain increases.Additionally,the viscoelastic mechanics of the PEMs is elucidated by varying the temperature and force.Finally,the weighting factor of compressive stress,temperature and time are obtained by multi-factor dominance analysis.This work shows that choosing the appropriate manufacturing temperature and stress is helpful to realize high-performance manufacturing of the PEM surface structures.
fuel cellsproton exchange membranemicro hot embossingthermo-mechanical couplingconstitutive model
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