What Is Aluminum Plastic Film for Lithium Battery?

The aluminum-plastic film is the necessary packaging material for flexible packaging lithium batteries, which mainly plays the role of protecting the internal cell. Due to the advantages of flexible shape and size, light design, and large specific capacity, the soft-pack lithium battery encapsulated by the aluminum-plastic film is widely used in the field of consumer electronics and new energy vehicles.

Introduction to aluminum-Plastic film

Aluminum-plastic composite film (hereinafter referred to as "aluminum-plastic film") is a composite material composed of an outer nylon layer (ON layer), an intermediate aluminum foil layer (AL layer), and an inner thermal seal layer (CPP or PP), which is bonded by an adhesive between layers. The aluminum-plastic film is the key material for packaging the battery core of flexible packaging lithium batteries. After the single battery is assembled, it is sealed with aluminum-plastic film to form the battery. Compared with steel case, aluminum case or plastic case and other packaging materials, the aluminum-plastic film has the advantages of light quality, thin thickness and flexible appearance design, and has been widely used in 3C consumer electronics, power batteries, energy storage and many other fields.

Polymer soft pack lithium battery is made of aluminum-plastic film wrapped by gel polymer electrolyte, with ultra-thin, high safety characteristics, can be made into any shape and capacity of the battery, the main downstream is notebook, mobile phone, smart wear, power tools, unmanned aerial vehicle and other consumer electronics products. Apple is the largest purchaser of lithium polymer batteries. Its iPhone, iPad, MacBook and other mobile electronic products all adopt lithium polymer batteries, taking a dominant position. Lithium-polymer batteries are already being used in consumer electronics.

New energy vehicle batteries can be divided into square, round and soft-wrapped lithium batteries according to their shapes. Square and circular batteries are mostly encapsulated by steel shell and aluminum shell. Aluminum-plastic composite film is the packaging material of soft-wrapped lithium batteries. As the soft-pack lithium battery saves the volume and weight of the system, is higher than other types of batteries in terms of specific capacity, and has the advantages of good safety performance, small internal resistance and flexible appearance design, many automobile enterprises begin to adopt the soft-pack battery technology route.

Due to the presence of electrolyte inside the battery, the soft packaging material is required to resist the swelling, dissolution and absorption of organic solvents, while ensuring the strict barrier of oxygen and water. Therefore, the aluminum-plastic film is not only the simple outer packing of flexible battery but also one of the important components of a flexible lithium battery. If the package is damaged, it is likely to bulge or even leak, and the battery will not be usable.

Therefore, the design, manufacture and application technology of aluminum-plastic film materials are qualitatively different from ordinary composite packaging materials. The technical difficulty exceeds that of the diaphragm, the positive electrode, negative electrode, electrolyte and aluminum-plastic film, which is also a relatively difficult link in the field of lithium-ion battery materials.

The above information is provided by an aluminum-plastic film factory.