Characteristics of lithium battery separator

　　The main performance requirements of lithium-ion battery diaphragm include: thickness uniformity, mechanical properties (including tensile strength and puncture resistance), air permeability, physical and chemical properties (including wettability, chemical stability, thermal stability, and safety).

　　1. It has electronic insulation to ensure the mechanical isolation of positive and negative electrodes.

　　2. It has a certain aperture and porosity to ensure low resistance and high ionic conductivity, and has good permeability to lithium ions.

　　3. Since the electrolyte solvent is a strong polar organic compound, the diaphragm must be resistant to electrolyte corrosion and have sufficient chemical and electrochemical stability.

　　4. It has good wettability to electrolyte and sufficient water absorption and moisturizing capacity.

　　5. It shall have sufficient mechanical properties, including puncture strength, tensile strength, etc., but the thickness shall be as small as possible.

　　6. Space stability and flatness are good.

　　7. Good thermal stability and automatic shutdown protection performance. The power battery has higher requirements for the diaphragm, and usually uses a composite membrane.