Aluminium foil surface passivation treatment process and aluminium plastic film

Abstract

The invention belongs to the technical field of lithium batteries, and particularly relates to an aluminium foil surface passivation treatment process and an aluminium plastic film. The aluminium foil surface passivation treatment process comprises the following steps: (1) carrying out alkali washing and oil removal on the surface of an aluminium foil, carrying out roll coating and impregnation double-sided passivation treatment in sequence, and uniformly coating two sides of the aluminium foil with a chromium-free passivation agent through a non-contact trowelling air knife; and (2) baking the aluminium foil through a non-contact air flotation oven. The aluminium plastic film comprises a nylon layer, an aluminium foil layer and a CPP layer. The aluminium plastic film comprises a nylon layer, a CPP layer and an aluminium foil layer prepared through the passivation treatment process in the invention. According to the invention, the two surfaces of the aluminium foil can be passivated at the same time; the aluminium foil surface passivation efficiency is greatly improved; meanwhile, the contact area between the aluminium foil and an equipment roller is greatly reduced; the equipment corrosion probability is reduced; and the aluminium foil passivation treatment yield is increased.

Description

technical field [0001] The invention belongs to the technical field of lithium batteries, and in particular relates to an aluminum foil surface passivation treatment process and an aluminum-plastic film. Background technique [0002] Lithium-ion batteries are one of the greatest inventions of the 21st century. Its appearance has greatly changed people's production and lifestyle. Lithium-ion batteries are widely used in electronic products, such as notebook computers, new energy vehicles, smart phones, electric toys and other products. Lithium-ion batteries are mainly composed of outer film, glue, aluminum foil treatment layer, aluminum foil layer, glue and heat-sealing layer. The aluminum-plastic film is in direct contact with the inside of the lithium battery, and mainly plays the role of wrapping the entire battery and blocking water vapor and electrolyte. [0003] Over time, a series of chemical reactions will occur inside the lithium battery, resulting in the formation...

AI Technical Summary

Problems solved by technology

However, hexavalent chromium is toxic and carcinogenic, and trivalent chromium also pollutes the environment to a certain extent

As time goes by, the country pays more and more attention to environmental protection. Therefore, the traditional chromium-based conversion coating will inevitably be gradually replaced. Moreover, the traditional chromium-based roller coating process has relatively large defects. On the one hand, chromium-based passivation The acidity of the solution is extremely strong (pH < 1), which will seriously corrode the roller coating equipment. On the other hand, the traditional roller coating is a single-sided coating process, while the aluminum foil in the aluminum-plastic film needs double-sided passivation treatment, so the aluminum foil needs to pass through two The anti-corrosion effect can only be achieved by the first roller coating. The more times the aluminum foil passes through the roller, the greater the loss of the aluminum foil. The two roller coatings will cause a significant drop in the yield of the aluminum foil, and the increase in energy consumption will eventually lead to the production cost of the product. rise

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