After the electrodes are rolled and slit into smaller electrode bands, these coils need to be dried. For a high-quality battery, it is essential to remove all humidity and solvent residues. The drying process uses heat and vacuum to remove all residues which weaken the battery capabilities. Vacuum plays an essential role during the drying process because it enables a much lower residual humidity of the electrodes.
This step requires a robust and reliable vacuum system. The vacuum pumps need to withstand humidity and solvent traces. Furthermore, purity in process is a must, so dry compressing pumps become relevant to avoid backstreaming of oil particles towards the coils. The vacuum drying can either take place in a batch dryer or an in-line dryer.