锂离子电池隔膜物化性能变化趋势研究

Study on changing trend of separators physicochemical performance in Li-ion battery

选用干法单向拉伸PP隔膜和湿法双向拉伸PE隔膜,研究了两款隔膜在不同温度环境(常温、-20℃、55℃)电解液中浸泡一周后,隔膜物化性能变化规律。研究发现,隔膜的穿刺强度和拉伸强度大小顺序为:未浸泡>常温>-20℃>55℃。另外,单向拉伸的隔膜的力学性能呈现各项异性,隔膜纵向(MD)的力学性能优于横向(TD),这与单向拉伸工艺所形成的特定孔隙结构相关。

The dry uniaxial tensile PP separators and wet biaxial tensile PE separators were selected to study the changing regulation of the separators physicochemical performance when they were immersed in electrolyte for a week under different environmental temperatures （room temperature, -20℃, 55℃. The results show that the order of the puncture and tensile strength of the separators is as follows： un-immersed separators〉room temperature〉 -20℃ 〉55℃. In addition, the mechanical properties of the uniaxial tensile separators are anisotropic. The mechanical properties of the separator in machine direction are better than the transverse direction, which is associated with the specific pore structure formed by the uniaxial tensile process.