Introduction: Aluminum plastic composite film (hereinafter referred to as "aluminum plastic film") is mainly composed of on / Al / CPP (outer nylon layer / middle aluminum foil layer / inner heat seal layer) composite material, and the layers are bonded by adhesive. Aluminum plastic film is one of the key materials for flexible packaging of lithium battery, which can protect the inner cell material. It has strict requirements in barrier, cold stamping formability, puncture resistance, chemical stability and insulation. Compared with cylindrical and square aluminum shell, flexible battery has obvious advantages in energy density, safety and flexibility, and has been widely used in 3C consumer, new energy vehicles and energy storage fields. Aluminum plastic film has an important impact on the performance of the battery. The materials used for lithium battery cell packaging should have the following characteristics: 1; 2. It has good heat sealing performance; 3. The inner material is resistant to electrolyte and strong acid corrosion; 4. It has good ductility, flexibility and mechanical strength. use: The aluminum plastic film is cut into the required shape and heat sealed. The recommended temperature is 180-205 ℃ and the time is about 10-20s