1. It serves as electronic insulation between the positive and negative electrodes: the separator with good insulation provides a good safety guarantee for the battery, and the good puncture strength and tensile strength can prevent the separator from being broken by burrs and dendrites. cause a short circuit inside the battery. In addition, the thickness and thermal stability of the separator are also important factors affecting the safety of lithium-ion batteries.

2. Supply migrating microporous channels for lithium ions, which determines the charge-discharge and cycle performance of the battery. Therefore, the separator must have a high porosity and a uniform distribution of micropores.