What kind of aluminum plastic film is needed for domestic lithium batteries

Aluminum plastic film is one of the five major materials for lithium ion batteries and is a flexible lithium battery packaging material. The aluminum plastic film consists of an outer nylon layer / binder / middle layer aluminum foil / binder / inner layer hot seal layer, a total of five layers, each layer of functional requirements are relatively high.

1, the role of lithium-ion battery aluminum plastic film

Aluminum plastic film is one of the five major materials for lithium ion batteries and is a flexible lithium battery packaging material. The aluminum plastic film consists of an outer nylon layer / binder / middle layer aluminum foil / binder / inner layer hot seal layer, a total of five layers, each layer of functional requirements are relatively high.

2, Lithium-ion battery on aluminum plastic film requirements

The barrier, puncture resistance, electrolyte stability, high temperature resistance and insulation of aluminum plastic film affect the performance of lithium-ion batteries. Any loss in any aspect may lead to a reduction in battery performance and direct scrapping. Aluminum plastic film is produced by precision coating technology. At present, Japanese companies have the most advanced precision coating technology in the world.

3, lithium ion battery aluminum plastic film process

Dry and hot process is the main production process of aluminum plastic film. The dry process is made by directly pressing aluminum and polypropylene with an adhesive bond, and the hot process is made by using MPP between aluminum and polypropylene and then slowly heating up.

The aluminum plastic film produced by dry method is thin, has a good appearance, has excellent deep flushing performance and anti-short circuit performance, and the process is simple and low in cost. However, compared with the heat method, the electrolytic liquid and water resistance are poor. The advantages of the heat method are good in electrolytic fluid resistance and water resistance, but the deep flush molding performance and short-circuit protection performance are not as good as the dry method, and the appearance and cutting property are poor.

4, the global lithium-ion battery aluminum plastic film enterprises

Aluminum plastic film plays a key role in the flexible lithium battery, generally accounting for about 15-20 % of the core cost. However, due to the lack of technology in China, the aluminum plastic film market accounts for very little, accounting for less than 5 %. At present, 90 % of the domestic aluminum plastic film market is monopolized by Japanese manufacturers, mainly DNP(Greater Japan Printing), Showa Electric and T& T occupied.

Aluminum plastic film as a domestic lithium electric material has not yet been realized, and its gross profit rate is as high as 60-80 %. It is estimated that the current global market space for aluminum plastic film is only a few billion yuan. With the downstream demand release, the industry is expected to grow by more than 40 %, and the potential market size will reach 10 billion.

5, China's lithium ion battery aluminum plastic film gap

As the core material of the flexible battery, the production technology of aluminum plastic film is much more difficult than that of diaphragm, positive electrode, negative electrode, and electrolyte. It is one of the three high technologies in the lithium battery industry. From the point of view of product performance, there is a large gap between Chinese aluminum plastic film products and foreign products, mainly manifested in: aluminum foil surface treatment technology backward, pollution; The water treatment of aluminum foil will produce "hydrogen embrittlement", resulting in poor tear resistance of aluminum plastic film; The surface of aluminum foil is not enough, and the yield is poor; Polypropylene and high thermal conductivity aluminum foil surface composite easy to curl, produce layered crystals; Domestic adhesive formulation technology is poor, easy to appear the problem of delamination.

Due to the lack of these production technology, the maximum depth of aluminum plastic film produced in China is about 5mm, and it can not achieve good performance requirements. Foreign countries can reach 8mm, and some even reach 12mm. There is still a certain gap between the total and foreign products. In terms of thickness, the thinnest aluminum plastic film in China can only achieve 70 μm, and 112, 88, and 72 μm are mass-produced. The thinnest aluminum plastic film in Japan can achieve 40 μm, and 65 and 48 μm can also be mass-produced.

Why the manufacturing technology of aluminum plastic film is difficult to break through, in general, there are deficiencies in materials, equipment, and processes. The technical difficulty lies mainly in the control of the process-the precise control of the reaction conditions.

The page contains the contents of the machine translation.