The production process of lithium batteries is relatively complex. The main production processes include the stirring and coating stage of electrode production (front stage), the winding and injection stage of battery synthesis (middle stage), and the packaging inspection stage of formation packaging (back stage).

The front-end production process of lithium batteries is related to the core performance of the battery in the manufacturing of pole pieces. The corresponding lithium battery equipment mainly includes vacuum mixers, coating machines, roller presses, etc.

The result of the front-end process of lithium batteries is the preparation of positive and negative electrodes of lithium batteries. The first process is stirring, that is, mixing the positive and negative materials of solid-state batteries evenly, and then adding solvents and stirring them into slurry through a vacuum mixer. The mixing of components is the basis of the subsequent process of lithium batteries, and stirring is the basis for completing the subsequent coating and rolling processes.

The coating and rolling process is followed by slitting, that is, the coating undergoes a slitting process. If burrs appear during the slitting process, potential accidents will occur in subsequent assembly, electrolyte injection and other processes, and even during the use of the battery. Therefore, the front-end equipment in the lithium battery production process, such as mixers, coaters, roller presses, slitting machines, etc., are all core machines for battery manufacturing and are related to the quality of the entire production line.

Vacuum application description in lithium battery production

Electrode material slurry mixing, material transportation and storage vacuum degassing

1. In the early slurrying process of lithium battery production, the electrode slurry needs to be vacuum degassed to achieve pole roller coating;

2. The pumping gas is a mixed gas containing a certain amount of water vapor and organic solvent NMP volatiles (corrosion of copper) and residual material dust. Therefore, the screw dry vacuum pump is required to have a strong special medium processing ability;

3. The diameter of general dust particles is 0.1~10 microns, and the current good vacuum pump filter can only capture particles larger than about 2 microns , so the filter cannot effectively filter and intercept dust (using a 2-micron filter will affect the pumping speed of the vacuum pump). For example, using an oil-sealed vacuum pump will cause frequent oil changes and fail; the vacuum degree of the liquid ring vacuum pump is not enough, and it can only maintain a vacuum degree of -85KPa for a long time. The degassing cannot meet the needs of the process, but the actual application process generally requires about -95Kpa;

4. Screw dry vacuum pumps are often used to deal with this process. Their performance is far superior to claw dry vacuum pumps and multi-stage Roots vacuum pumps. Only one screw vacuum pump is needed for equipment vacuuming, and there is no need to configure a Roots pump to increase pressure and speed. However, the positive and negative electrodes should be equipped with vacuum pumps separately. If the same vacuum system needs to be combined for vacuuming, a vacuum valve must be configured when using it, and a single vacuum pump must be strictly controlled;

5. Comparison of dry vacuum pump characteristics