New energy batteries have become the core pillar of the country's new energy industry. With the exponential growth of new energy vehicles in 2021, the demand for lithium-ion batteries has risen sharply, further driving the market demand for battery aluminum foil. China's battery aluminum foil industry has experienced rapid development from research and development, trial production to production and export, and has gradually transformed from dependence on imports to independent production and batch exports. This development process is an important milestone in the development of China's new energy industry.
1. Lithium battery aluminum foil: positive current collector, key battery material
(1) Aluminum foil: Battery aluminum foil has become the fastest growing aluminum foil variety
Aluminum foil is a kind of aluminum rolled material. Aluminum foil is mainly about thickness. In the industry, aluminum products with a thickness less than 0.2mm are usually called aluminum foil. The edges are usually cut vertically and delivered in rolls. Aluminum foil can be divided into packaging foil and container foil, air-conditioning foil, electronic foil, battery aluminum foil, etc. according to downstream application fields. Among them, packaging and container foil and air-conditioning foil occupy the main market of aluminum foil, while battery aluminum foil accounts for a relatively small market share, only 5%. about. In 2020, domestic battery aluminum foil production will be approximately 70,000 tons, in 2021 it will be 140,000 tons, and in 2022 it will be 280,000 tons, with year-on-year growth of up to 100%, making it the fastest growing variety among aluminum foil products.
(2) Battery aluminum foil: Aluminum foil is used as a positive electrode current collector and has both performance and cost advantages.
In lithium batteries, aluminum foil materials are used in current collectors, tabs, and outer packaging aluminum-plastic films. What is usually called aluminum foil for batteries actually refers to aluminum foil for the positive electrode current collector of lithium-ion batteries. The current collector refers to the structural part that collects current. Its main function is to collect the current generated by the active material of the battery in order to form a larger current for external output. It needs to be in full contact with the active material. Therefore, the current collector needs to meet performance requirements such as high conductivity, strong corrosion resistance, good toughness, certain stiffness, and easy processing and molding. The chemical and physical properties of aluminum foil and copper foil just meet the above requirements, so the lithium battery industry usually uses aluminum foil as the positive electrode current collector and copper foil as the negative electrode current collector.
