聚乙烯/聚丙烯双层微孔膜制备的热处理工艺研究

Study on Heat Treatment Proc ess of Polyethylene/Polypropylene Double-layer Microporous Membrane

隔膜是影响电池安全性能和保证电池稳定运行和循环安全的关键材料之一,隔膜技术发展和产品质量成为电动汽车发展和推广的最主要瓶颈。本文通过研究热处理温度和时间对流延膜性能的影响,为三层微孔膜的制备提供可参考的实验数据。实验结果显示初始流延膜具有一定的硬弹性,已形成一定的有序平行排列片晶。随着热处理时间增加,PP、PE层的分子取向都得到了提升,片晶规整度得到提高;在热处理2 h时,两层热处理膜的综合性能达到最佳。进一步增加热处理时间,PE层的片晶规整度下降,导致两层热处理的弹性回复率轻微下降,对应的拉伸后微孔膜性能也有所下降。

The separator is one of the key materials that affect the safety performance of the battery and ensure the stable operation and cycle safety of the battery.The development of separator product quality have become the most important bottlenecks in the development and promotion of electric vehicles.This paper provides reference experimental data for the preparation of three-layer microporous membranes by studying the effects of heat treatment temperature and time on the properties of cast membranes.The experimental results show that the initial cast film has a certain hard elastic recovery ratio,and has formed a certain orderly parallel arrangement of lamellae.With the increase of heat treatment time,the molecular orientation of PP and PE layers has been improved,and the lamellar regularity has been improved;when the heat treatment is 2 h,the comprehensive performance of the two heat-treated films reaches the best.Further increasing the heat treatment time,the lamellar regularity of the PE layer decreases,resulting in a slight decrease in the elastic recovery rate of the two layers of heat treatment,and the corresponding decrease in the performance of the microporous membrane after stretching.