锂离子电池用ETFE/PE共混微孔隔膜的可控制备研究

With the advantages of thermal stability, chemical resistance, good mechanical properties and flame retardant, ethylene-tetrafluoroethylene copolymer (ETFE) is a promising material for lithium ion batteries (LIBs) separators. Giving consideration to both thermal shrinkage shortcoming and shutdown merit of commercial polyolefin microporous LIBs separators, ETFE is introduced to prepare LIBs separators. In this project, ETFE/PE/diluent/addition multi-component mixed thermodynamic equilibrium system will be established firstly. Then, the phase separation process of the ETFE/PE/diluents/addition system induced under different conditions and the microstructure of ETFE/PE blend membrane will be observed to investigate the mechanism of microporous membrane formation. And the influence of TIPS process conditions on the final microstructure of ETFE/PE blend membrane will be analyzed to study the microstructure controlling method. Finally, by a comprehensive analysis of factors affecting the ETFE/PE membrane performance as LIBs separators, a theoretical model will be established to describe the quantitative relationship between the separator performance and temperature, operation time, and the microstructure parameters of ETFE/PE blend membrane. So the key scientific problem about the quantification of relationship between the thermal stability and electrochemical performance of ETFE/PE separator and its microstructure parameters will be solved, which guides the optimization of LIBs separator microstructure. Through the study of this subject, ETFE/PE microporous separators with ensuring safety and excellent performance can be prepared as designed, which promotes the market of new energy vehicles powered by LIBs.

本课题针对锂离子电池隔膜高温闭孔与热收缩难以兼顾的难题，提出以耐热、耐有机溶剂、机械性能良好且阻燃的乙烯-四氟乙烯共聚高分子(ETFE)作为新型锂离子电池隔膜材料。通过建立ETFE/聚乙烯PE/稀释剂/添加剂多组分共混热力学平衡体系，观察不同条件下诱导产生的多组分共混体系相分离过程及ETFE/PE共混隔膜结构，进行成膜机理研究；分析制膜条件对终态膜微观结构的影响规律，研究ETFE/PE共混微孔隔膜的微观结构控制方法。全面分析隔膜性能，建立描述隔膜性能与温度、操作时间以及隔膜微观结构参数之间定量关系的理论模型，解决ETFE/PE共混隔膜的热稳定性及电化学性能与隔膜微观结构参数之间关系量化的关键科学问题，指导ETFE/PE共混隔膜微观结构调优。通过本课题的研究，设计并制备出安全可靠、性能优异的锂离子电池隔膜，推进动力型锂离子电池在新能源汽车中的应用。

本课题针对锂离子电池隔膜高温闭孔与热收缩难以兼顾的难题，提出以耐热、耐有机溶剂、机械性能良好且阻燃的乙烯-四氟乙烯共聚高分子(ETFE)作为新型锂离子电池隔膜材料。通过建立ETFE /稀释剂/添加剂多组分共混热力学平衡体系，观察不同条件下诱导产生的多组分共混体系相分离过程及ETFE隔膜结构以进行成膜机理研究；以提高锂离子电池隔膜热稳定性为目的，进行PTFE/PE复合膜以及UHMPE隔膜的制备及成膜机理研究；以及ETFE膜材料在电池行业的应用开发研究。