Modelling electrolyte-immersed tensile property of polypropylene separator for lithium-ion battery

摘要

Lithium-ion batteries have grown into remarkable energy resource thanks to the superior power and specific energy densities, astounding cycling performance, green sustainability, and extensive applicability. As an important component, the mechanical properties of separator notably affect the assembly quality and working safety of the battery. In this paper, aiming at the electrolyte-immersed and rate-dependent tensile properties of Polypropylene (PP) separators, comprehensive tensile tests concerning different circumstances are conducted. And more significantly, a representative volumetric element (RVE) modelling method is proposed, which is based on image reconstruction technique and realized through inp-launched finite element simulation. The essence of RVE modelling is straightly converting image pixels to finite elements with patterned nodes. The electrolyte immersion effect on PP material is explored through molecular simulation. The experimental results indicate that tensile behaviors are rate dependent and electrolyte immersion would lead to considerable weakening to PP separators. Therefore, mechanical properties of "wet" separators should be seriously considered in future designing. The simulation has successfully calculated the Young's modulus of the PP separators, which inspiringly agrees to that of the experimental. The modelling precision is reliable and the simulating errors are relatively small, revealing worthy applicability and promising outlook of the modelling method.