As we all know, the positive substrate of lithium-ion battery is aluminum foil, and the negative substrate is copper foil, which is coated and made into positive and negative electrode rolls for the next step of processing. The quality of the substrate has basically predetermined the performance of the battery, and the coating of the substrate is a very important part of the whole battery manufacturing process!

Coating methods from the original dip coating, extrusion development to the current state-of-the-art double-sided coating at the same time, are to improve the coating quality and performance of the pole piece, some domestic units with strong economic strength, in order to manufacture reliable performance of lithium-ion batteries, the cost of large sums of money to introduce expensive foreign pole piece coating machine.

Coating of the general process: coating substrate (foil) by the uncoiling device for release into the coating machine. The head and tail of the substrate are connected into a continuous belt in the splicing table, and then sent into the tension adjusting device and automatic deviation correcting device by the pulling device, and then enter into the coating device after adjusting the tension and position of the sheet path. Pole piece slurry is coated in the coating device according to the predetermined coating amount and blank length. In the case of double-sided coating, the front coating and blank length are automatically tracked for coating. After coating, the wet pole piece is sent to the drying channel for drying, and the drying temperature is set according to the coating speed and coating thickness. After drying, the pole piece is rewound after tension adjustment and automatic deviation correction for processing in the next step of the process.

The slurry coating of the pole piece is relatively thick, the coating volume is large, and the drying load is large. At present, hot air impact drying technology is commonly used. The positive electrode substrate is aluminum foil, which is chemically active and easily oxidized. In the manufacturing process of aluminum foil, a layer of dense oxide film is formed, which prevents the further oxidation of aluminum foil. As the oxide film is thin and porous, soft and has good adsorption, but high temperature and high humidity can destroy the oxide film and accelerate the oxidation reaction. At present, most of them are using single-sided coating, when the first side of the coating when the other side is completely exposed to the hot air in the air, and precisely coated (oil system) drying hot air to be in the 130 ℃ or so, such as the hot air in the water content is not effectively controlled will intensify the oxidation of the aluminum foil and affect the bonding of anode materials and aluminum foil, and even serious and even caused by the shedding.

The United States, Japan coating machine manufacturers for single-layer coating machine energy efficiency and aluminum foil oxidation problems, the development of the development of double-sided simultaneous coating technology, a complete solution to the coating of aluminum foil oxidation problems, but double-sided simultaneous coating machine price is not the general battery manufacturers can afford.