Q&A on the main situation of coating abnormalities

Question1: During the coating process, the areal density is always transversely distributed, light on both sides and heavy in the middle. What is the reason for the serious warping on both sides after one-sided baking?

Answer: The weight of the coating process is uneven, often related to the scraper, generally due to long-term use and wear, it is lighter on both sides and heavier in the middle. As for baking on one side and rolling on both sides, in general, it is still due to the low solid content of the slurry?and the large shrinkage during the baking process. In addition, too fast baking speed can also affect.

Question2: What is the rate of baking heating? Can it be left overnight without baking?

Answer: In the industry, the oven is set to the temperature first, and the whole oven has been said before, first heating up, then heat preservation, and finally cooling. After coating, it is recommended to bake first, not overnight. For laboratory baking, can put the separator?directly in the oven, need to be careful not to vacuum, and the temperature should not be too high. The electrode after coated, try not to leave it overnight and dry it directly. For example, oily cathodes are easy to absorb water and need to be dried as soon as possible.

Question3: Will there be craters in both the?cathode?and anode?electrodes?

Answer: In principle, there will be shrinkage porosity in foreign bodies, so both cathode?and anode?electrodes will have them, but generally the anode electrode coating has many more problems than the cathode?electrode.

Question4: Why can soft particles pass through the screen?

Answer: Soft particles are generally understood to be soft agglomeration, which can be squeezed through the screen under pressure.

Question5: If the particle size of the same material becomes smaller, how to deal with slurry sedimentation?

Answer: The reason should be that the particle size becomes smaller, the more glue is needed to bond the particles, so the amount of glue needs to be increased.

Question6: Soft particles can also cause discontinuous scratches, right?

Answer: Yes, soft and hard particles can easily clog the coating port and cause streaks in the coating.

Question7: Does thickening after grinding have an impact on material properties?

Answer: Grinding destroys the structure of the active material particles, which can be fatal for many coating materials. Therefore, for the surface coating material, it is basically not recommended to disperse by grinding.

Question8: Conductive agents tend to agglomerate?

Answer: Generally speaking, the active materials in the industry are relatively easy to disperse, mainly conductive carbon, or some adhesives are not effectively dissolved, resulting in poor dispersion.

Question9: How should the rheology of slurry be analyzed?

Answer: It can be tested with a rheometer. For enterprises, the easiest way is to use a slurry that is normally used in mass production as a control group, and then analyze it with a rheometer to see the relationship between the viscosity and time of the slurry, because the stability of the slurry is relative.

Question10: How to effectively improve the excessive coating stress? Add alcoholic solvents?

Answer； Adding alcohols is also a method, such as adding NMP to the anode slurry.