How do you prevent lithium-ion batteries from coating darkness?

　　Author ：Iflowpower – Portable Power Station Supplier

1. To ensure the consistency of coating, it should be paid to the change in the viscosity of the slurry, the change in the height of the hopper, changes in the coating speed; 2, the thin layer of the slurry on the aluminum foil into the oven dry, remove NMP Solvent (NMP boiling point 202 ¡ã C, flash point 95 ¡ã C). Drying is too slow, the surface of the coating is fluidity, the thickness is unstable, the drying is too fast, the surface forms a PVDF film layer, and the internal NMP solvent volatilizes can cause the surface layer to wrinkle, in order to ensure the average evaporation of NMP, usually use segmented drying, The highest temperature in the middle section.

The positive electrode is generally 100-130 ¡ã C, if the aqueous system is used, the drying temperature is generally 75-90 ¡ã C; and the drying process NMP volatilizes, the composition of the coating paste is constantly changing, so the amount of NMP solvent of the slurry, temperature rise The mode and heating time have an effect on this; The active substance will be peeled off, thereby causing short circuit in the battery. In addition, the drying temperature and drying time are not appropriately caused by aluminum foil oxidation and polarity polarity; 4, coating and drying should be the first three inspection - thickness, quality, size meet the requirements, and test the corresponding pulp on time Speed, baking time, gap, etc. Explanation of dark laces of coating strips: Darkness is due to coating, the surface portion of the polar surface is uneven, the color difference occurs, and the appearance is dark.

The difference in thickness is might be (1) due to the blade of foreign matter or the surface of the knife in the slurry (have a gap), causing a phenomenon that the surface thickness of the pole surface is uneven; (2) after the roller pressure or the roller pressure Linear traces. Due to the particles that are not open due to the knife, or a small dry slurry card is caused on the kn.