Analysis of lithium-ion battery coating technology

It is well known that the anode substrate of lithium-ion battery is aluminum foil, and the cathode one is copper foil, which is made as anode and cathode pole piece after coating and continue to process next steps. The pole piece quality basically decides some performances of lithium-ion battery. So, the substrate coating is a very important part of the whole battery manufacturing process.

Coating method by the original dip coating, extrusion development up to now the most advanced double-sided coated at the same time, they are in order to improve the coating quality and performance of plate, some economic strength of the domestic units, in order to produce reliable performance of lithium ion battery, spend large sums of money to introduce foreign expensive piece of coating machine.

Apply the general technological process: coating substrate rolling device (foil) by let out into the coating machine. The beginning and the end of the substrate in sheet connected into continuous bands by pulling the device into the tensioning device and automatic correction device, after adjust the slice of tension and slice road location into the coating device. Sheet size in the coating at predetermined blank length segments coating and quantity of the coating. When double coating, automatic tracking positive coating and coated blank length. Coating is into the dry way to dry the wet sheet, drying temperature set according to the speed of coating and coating thickness. After drying of the pole piece by tension adjustment and automatic correction after winding, processing for the next process.

Pole piece thick slurry coating, coating weight, large load of drying. Current impact hot air-drying technology is widely accepted. The anode substrate for aluminum foil, aluminum foil of the chemical nature very lively, very easy to oxidation. In the process of manufacturing aluminum foil in a dense layer of oxide film, to prevent further oxidation of aluminum foil, because with thin oxide film and porous, soft, has good adsorption, but high temperature and high humidity can damage the layer of oxide film, accelerate the oxidation reaction. Now, most of all is to use single coating method, when the first side coating on the other side is completely exposed to the air in the air, and the coating (oil), dry hot air to about 130 ℃, such as hot air moisture content has not been effective control will add great the oxidation of aluminum foil and affect the anode material and aluminum foil adhesive, serious and even cause loss.

Against the function of single-layer coating and aluminum foil oxidation problem, coating machinery manufacturer in the U.S. and Japan developed double-side coated technology, completely solved the problem of oxidation of aluminum foil during coating, but at the same time, double-side coating machine is not affordable for general battery manufacturers.

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