Introduction to the production process of lithium-ion battery pole pieces

1. The meaning of coating Slurry coating is the next process after the preparation of the slurry. The important goal of this process is to evenly coat the positive and negative electrode sets with the slurry with good stability, good viscosity and good mobility. Fluidly. Pole piece coating is of great significance to lithium-ion battery packs, and the following points are important at this moment: 1. It is of great significance to the product battery capacity. In the coating process, if the pole piece is in the front, middle and back three positions, the positive and negative If the thickness of the slurry coating is different, it is easy to cause the battery capacity to be too low or too high, and it is easier to form lithium in the battery cycle process, which affects the battery life. 2. It is of great significance to the safety and performance of the battery. Before coating, do 5S things to ensure that no particles, debris, dust, etc. are mixed into the pole pieces during the coating process. If mixed with debris, it will cause a short circuit inside the battery. In severe cases, the battery will catch fire and explode. What the battery factory concealed in the contest is that the capacity difference and cycle life of a batch of batteries are quite different, so in the pole piece coating process, it is necessary to ensure that the parameters before and after the pole piece are consistent. 3. It is of great significance to the battery life. The big difference before and after the slurry coating, the mixing of dust in the pole piece, the uneven thickness of the pole piece, etc., are all related to the black and white of the electrochemical function of the battery. 2. Coating method According to acquaintance, the coating equipment is mainly composed of winding and unwinding unit, feeding unit, tension control system, coating head, oven and other departments. Coating can be divided into transfer coating and extrusion coating. 1. The transfer type coating roller moves the slurry, adjusts the blade gap to adjust the amount of slurry transfer, and operates the back roller or coating roller to transfer the slurry to the substrate, and control the coating layer according to the process requirements. The thickness can reach the weight requirement. At the same time, the solvent in the slurry spread on the substrate is removed by drying and heating, so that the solid matter is well bonded to the substrate. The benefit is that the slurry viscosity is not high, it is easy to adjust the coating parameters, and there is no blockage, etc. The disadvantage is that the coating accuracy is poor for the power lithium battery, and the consistency of the pole piece cannot be guaranteed. The slurry is exposed to the atmosphere between the rolls, which has a partial effect on the properties of the slurry. 2. The extrusion coating and feeding system delivers the paint to the screw pump, and then the slurry is powered to the extrusion surface. The slurry is made into a liquid film by extrusion and then coated on the moving current collector. After drying, a uniform coating is formed. The advantage is that the pole piece after coating is very symmetrical and high precision, the coating edge is flat, the closed operating system is not affected by foreign matter, and it is suitable for mass production. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Clarification of the important identity of lithium-ion battery electrolyte